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By A. Szirmae, Hsun Hu

The early stages of recrystallization in a 70 pct cold-rolled Si-Fe crystal of the (110) (0011) orientation were studied with a Siemens electron microscope. Orientation studies based on electron-diffractzotz. patterns confirm the results of previous texture analysis. The driving energy for recrystallizatior and the critical radius for growth were calculated from the dislocation energy and the energy of the subgrain bourzdaries, and it was found consistent with the observed size of the recrystallized grains. The recrystallization characteristics of crystals with different initial orientations are discussed. The recrystallization of cold-rolled (110)[001] crystals of Si-Fe has been widely studied by various investigators.1-4 Their results on both deformation and annealing textures are in good agreement. The rolling texture after 70 pct reduction consists mainly of two crystallographically equivalent (111) [112] type textures and a minor component of the (100) [011] type. The latter is derived from the deformation twins, or Neumann bands, which are formed during the early stages of deformation and later rotate to the (100) [011] orientation upon further rolling reduction. Between the two main (111) [112] type textures, there is some orientation spread, because of which very low intensity areas appear in the pole figure. If these very low intensity areas are considered to be a very weak component in the texture, then a (110) [ 001 ] orientation may be assigned to them. When this rolled crystal is annealed at a sufficiently high temperature for recrystallization, the texture returns to a simple (110) [001]. The purpose of the present investigation was primarily to seek a better understanding of the recrystallization process by using the electron transmission technique. The (110) [0011 type of crystal was selected because orientation data for it are well known from previous studies with conventional techniques. Direct observations on the recrystallization of such a crystal have also been made by using a hot-stage inside the electron microscope, and the results will be reported in another paper. MATERIAL AND METHOD A single-crystal strip of the (110) [001] orientation was prepared from a commercial grade 3 pct Si-Fe alloy by the strain-anneal technique.= The strip was approximately 0.014 in. thick, and was rolled 70 pct at room temperature to a thickness of 0.004 in. Specimens were cut from the rolled strip and were annealed in a purified hydrogen or argon atmosphere. They were then electrolytically polished in a chromic-acetic acid solution to very thin foils. Best results were found by polishing first between two narrowly spaced flat cathodes with the specimen edges coated with acid-resisting paint, followed by polishing between two pointed electrodes until a hole appeared in the center as described by Bollmann.6 It was found that a thin transparent film always formed along the thin edges of the polished specimen. This film was then removed by rinsing the specimen very briefly in a solution of alcohol with a few drops of HF or HCl. RESULTS AND DISCUSSION 1) The Deformed Crystal. From the electron-diffraction patterns taken at various areas of an as-rolled specimen, the texture components as deduced - from ordinary pole-figure analysis were confirmed. Over most of the areas where orientation was examined, a (111) pattern with a [112] direction parallel to the rolling direction was obtained. This corresponds to the main deformation texture of the (111) [112] type. In a few areas the diffraction pattern was (100) [Oil], corresponding to the minor-texture component derived from the Neumann bands. The (110) [001] orientation, which corresponds to the very weak intensity area in the pole figure, was found infrequently. A typical example of the deformed matrix having the (111) type main texture is shown in Fig. 1, where (a) is the microstructure and (b) is the diffraction pattern taken from that area. It was also frequently observed that in other areas more or less continuous rings of weaker intensity were superimposed on the simple (111) diffraction pattern, suggesting the presence of a wide range of additional orientations. Other evidence indicated that the recrystallization characteristics are different in these two different types of areas. The hot-stage observations which provide this evidence will be discussed in another paper. AS shown in Fig. l(a), numerous dislocation-free areas of very small size are embedded in the "clouds" of high-dislocation density. This indicates that the deformation of a single crystal, even after a rolling reduction of 70 pct, is far from uniform on a micro-

Jan 1, 1962

By R. K. Dann, L. W. Roberts, R. B. Benson

The mechanical properties of 300-series stainless steels were investigated in both high-pressure hydrogen and helium environments at ambient temperatures. An auslenitic steel which is unstable with respect to formation of strain-induced a (bee) and € (hcp) mar-tensile is embrittled when plastically strained in a hydrogen environment. A stable austenitic steel is not embriltled when tested under the same conditions. The presence of hydrogen causes embrittlement at the mar-lensitic structure and a definite change in the general fracture mode from a ductile to a quasicleavage type. The embrittled martensitic facets are surrounded by a more ductile type fracture which suggests that the presence of hydrogen initiates microcracks at the martensitic structure. If a steel is unstable with respecl to fortnation of strain induced martensile, plastic deformation in a hydrogen environment will produce rapid embrittlement of a notched specimen in comparison to an unnotched one. FERRITIC and martensitic steels can be embrittled by hydrogen that has been introduced into the alloys, either by thermal or cathodic charging prior to testing.1-5 However, conflicting reports exist as to whether austenitic steels that are stable or unstable with respect to formation of strain-induced martensite can be embrittled by hydrogen.8-12 A recent investigation has shown that cathodically-charged thin foils of a stable austenitic steel can be embrittled.13 An earlier investigation of a thermally charged 18-10 stainless steel revealed a significant decrease in the ductility only at the lowest test temperature of -78°C, although strain-induced bee martensite was shown to be present in one specimen tested at ambient temperatures.' When martensitic steels are tested in a hydrogen atmosphere, they are embrittled.'4-'7 It has been observed in this Laboratory that 304L steel, which is unstable with respect to formation of strain induced martensite, forms surface cracks when plastically strained in a high-pressure hydrogen environment. Work in progress elsewhere concurrent with this investigation has also established that 304L is embrittled when tested in a high-pressure hydrogen atmosphere." The objective of this investigation was to study the effect of a high-pressure hydrogen environment on the tensile properties of a stainless steel that contained strain-induced martensite (304L) and one that did not (310). EXPERIMENTAL TECHNIQUES Notched and unnotched cylindrical specimens were machined from 304L* and 310 rods that were heat- treated at 1000°C in argon for 1 hr followed by a water quench. The chemical analyses of these steels are given in Table I. The unnotched specimens had a reduced section diameter of 0.184 & 0.001 in., a gage length of 0.7 in., and were threaded with a 0.5-in.-diam. thread on each end. The notched specimens had a reduced section diameter of 0.260 * 0.001 in. and a 0.75-in. gage length, with a 30 pct 60 deg v-notch at the center. The notch had a maximum root radius of 0.002 in. The tensile bars were fractured in a hydrogen or helium atmosphere of 104 psi at ambient temperatures. The system used for mechanically testing the specimens is to be described in detail elsewhere.19 Several specimens of each type were tested in air using an Instron testing machine. The same yield strength and ultimate tensile strength were obtained in 104 psi helium with the above system as with the conventional testing machine. Magnetic analysis was employed to determine that there was a (bee) martensite in plastically deformed 304L and that it was not present in plastically deformed 310. The magnetic technique depended on allowing the material being studied to serve as the core between a primary and secondary coil. Thus, any change in the amount of magnetic material present between the annealed and plastically deformed steels will be indicated by corresponding changes in the induced voltage in the secondary circuit." The ratio of the output signal of a nonmagnetic stainless steel to a completely magnetic maraging steel was 2000 to I. Several unnotched 304L bars tested in hydrogen were analyzed for hydrogen by vacuum fusion analysis. There was an increase in the hydrogen content to approximately 2 ppm for the specimens tested in hydrogen, as compared to less than 1 ppm for the as-received material. Several thin sections cut from notched areas of 304L specimens tested in hydrogen and containing the fracture surface contained approximately 1.5 ppm H. The accuracy of these determinations was estimated to be ± 50 pct.

Jan 1, 1969

By G. R. Pickett

Examples are presented which show that the velocity~ amplitude, attenuation and apparent frequency of several acoustic waves can be recorded in the borehole. Examination of such recordings, termed "character" logs, indicates that the wave types observed include a refracted compressional wave and a wave which travels with formation shear velocity. Laboratory data are used to show that compressional and shear wave velocities are dependent on porosity, effective stress and lithology; but that the change in reciprocal velocity per unit change in porosity is larger for shear waves than for compressional waves. We, therefore, conclude that. the accuracy of porosity determinations can sometimes be improved by use of shear wave velocities, provided that the shear wave amplitudes are large enough to delineate the shear arrival from the preceding compressional arrival on the character log. Borehole data are presented which show that the difference between shear wave and compressional wave reciprocal velocities can be used to predict porosities. This is a refinement which may allow the prediction of porosities from single-receiver acoustic logs without introduction of errors from borehole fluid traveltimes. Laboratory and field data are presented to show that the relationship between compressional and shear wave velocities can be used to indicate lithology. An example is presented to show that fractures usually cause a greater reduction in borehole shear wave amplitudes than in compressional wave amplitudes, an effect which may offer a more reliable means of detecting fractures. The complexity of the borehole acoustic wave train can rake presently available cement bond logs highly sensitive to the gate and bias settings used. The character log offers a means to circumvent possible misinterpretations by recording all amplitudes, from which the interpreter can select the appropriate data for evaluating the cement bond. Character logs may also be used as a quality control for open-hole transit-time logs when existence of small compressional wave amplitudes interferes with the proper functioning of bias-controlled timing devices. Evaluation of the potential uses of character log data is not complete; but a character log presented in a form convenient for routine use would be a desirable addition to currently available logs. To summarize, possible applications for such a log in formation evaluation include the following (1) quality control of transit-time logs, (2) refinement of porosity predictions, (3) determination of lithology, (4) improvement of fracture detection and (5) improvement of cement bond evaluation. Suggestions are made regarding the requirements for a suficient but practical character log for routine use. INTRODUCTION Acoustic logs have become a widely used porosity tool in formation evaluation. In addition, there is a growing application of acoustic logs in cement bond evaluation and fracture detection. These applications have mainly involved the use of logs of first-arrival transit times and amplitudes and have not included detailed studies of the complete signal. The purpose of this paper is to show that significant benefits in formation evaluation can be gained by a more complete use of the acoustic wave train generated in the borehole by an acoustic logging tool. We hope that this discussion will also stimulate further development of logs suitable for routine use so that these benefits may be realized. Examples of acoustic wave train logs, termed "character" logs, are presented to show that several identifiable acoustic waves are present in the borehole. The measurable characteristics of these acoustic waves and some of their relations to formation properties of interest are also discussed. The more obvious potential uses of character logs are listed, and some suggestions are made regarding the requirements for a sufficient but practical character log for routine use. CHARACTER LOGS Some 10 years ago, Vogel' and Summers and Broding' noted that the signals received uphole from an acoustic logging tool located in a borehole had a number of interesting characteristics. The logging tool consisted of two or more pressure transducers spaced on an acoustically insulated body (Fig. la). One of the pressure transducers was used as a transmitter to generate pressure waves in the borehole fluid. The other transducer served as a receiver to detect any pressure waves reaching it in the borehole. The receiver then converted these pressure waves to electrical signals which were transmitted to the surface and displayed on an oscilloscope as a record of time vs receiver-signal amplitude. Fig. lb is a schematic representation of a typical record. The interesting characteristics seen in the earlier' and subsequent experiments were (1)

By A. E. Blakeslee

Morphological and electrical properties of GaAs epitaxial layers are influenced not only by changes in the nominal substrate orientation but also by small amounts of misorientation from the exact crystal planes. Deviations up to 5 deg from {11IA}, {11IB}, and (100) planes were investigated. Growth rates increase progressively with angle, approximately I u per hr per deg. Size and density of growth pyramids fall off with increasing angle, but other effects that are deleterious to the surface may occur which are heightened by increased misorientation. Carrier concentration decreases and electron mobility consequently increases as the angular offset increases, except in the case of strong compensation, where the mobility trend is reversed. It has long been known that changes in the crystallo-graphic orientation of the substrate may cause pronounced effects on the morphological properties of vapor grown semiconductor films. Reports of orienta-tion-dependent growth rates and surface characteristics are as old as the literature on epitaxy itself. shawl has recently published a comprehensive study of the dependence of growth rate on substrate temperature and orientation in epitaxial GaAs. It is also well-known that misorienting the substrate surface a few degrees away from the nominal low-index crystal-lographic plane often produces a much smoother epitaxial surface. This was reported by Tung2 for silicon, Reisman and Berkenblit3 for germanium, and by Kontrimas and Blakeslee4 for GaAs, and use is commonly made of this fact in the semiconductor industry to help guarantee smooth vapor deposits. The effects of substrate orientation on the carrier concentration and mobility of vapor grown GaAs were first documented by williams5 in 1964 and have been observed by several other authors since then,6,7 but no one has yet reported a careful study of how small changes influence these properties. We have made such a study and have found that sizable differences in growth rate, morphology, carrier concentration, and mobility can indeed be observed for epitaxial films grown on substrates that are oriented by progressive small increments away from the exact crystal plane. EXPERIMENTAL Early in the investigation an arsine synthesis system of conventional design8 was employed to produce growths on {111A}-oriented GaAs substrate crystals. In that early work, pronounced effects on carrier concentration and electron mobility were observed as a function of slight misorientation from this low index plane. That observation led to the more careful study that is reported here. An AsC13 system, differing in major aspect from those commonly in use today9 only in that the reactor is vertical rather than horizontal, was used for the detailed study. The gallium source was at 900°C and the substrates were at 750°C. The flow rate of pal-ladium-diffused H2 through the AsCl3 bubbler was 200 cu cm per min, and the flow rate of bypass H2 was also 200 cu cm per min. The substrates consisted of chro-mium-doped semiinsulating GaAs to facilitate elec-trical evaluation of the overgrowth by means of Hall and conductivity measurements on conventional eight-legged Hall bridges. They were misoriented by 0 to 5 deg from the {111A}, {111B}, and (100) planes, toward the (100) from the {111A} and {111B} and randomly toward the <111A> or <111B> from the {loo). The crystals were oriented for sawing by the Laue back-re-flection technique, which is good only to about ±1/2 deg; but after polishing or sometimes after epitaxial growth the wafers were checked by a diffractometer technique which is accurate to about * 0.1 deg. After lapping, the wafers were polished with NaOCl after the technique of Reisman and Rohr,10 and just before use they were cleaned in NaOC1, thoroughly rinsed with de-ionized water, and blown dry with nitrogen. Each run employed four wafers, each misoriented by differing amounts from one of the three major faces, and at least two runs were made for each orientation. The runs were continued long enough to provide at least a 15-µ or thicker layer. SURFACE MORPHOLOGY The appearance of all the films that were grown in a given run always changed from wafer to wafer as a function of increasing misorientation, but not always in the same regular fashion. At least three different trends were observed. These are more easily seen than described, and reference to the series of photo-

Jan 1, 1970

By Chas. A. R. Lambly

In the extreme northeast corner of the State of Washington, on the Canadian border, lies the Metaline mining district. This district is old in history, but young in production. Geology The Metaline district is a zinc-lead area of the replacement type in dolomite and limestone. The ore bodies of the Josephine horizon are in many ways similar to the ore bodies of the famous Tri-State zinc fields. The beds are faulted and folded and have varying low dips in varying directions, and underlie large areas of the district. History Production started in 1927 on a very limited basis. The property is now mining and milling 700 tons per day. The mine is opened by adit tunnels and a vertical shaft. As the ore horizons gained depth, it was necessary to sink inclines to follow the ore horizon (see Fig 1). From 1927 to date, approximately 600,000 ft of diamond drill was put down This work indicated that suficient tonnage existed to justify a redesigning of the whole operation, surface and underground. After four years of general study, the following program was planned: 1. A new mine entrance, which would be an incline, that could follow the ore body down at whatever pitch was necessary. The incline will be equipped with conveyors for the moving of ore and waste to the surface and with tractor-type locomotives for man and supply transportation. 2. The new incline also required a new type of mining which was developed and is now in use. It is called contour mining and will be described in a future paper. 3. The new incline exit would necessitate the moving of the mill and mine shops across the Pend Oreille River. This part of the program is now underway. The Incline The sinking of the incline was to start as soon as World War II ended and was as follows: The first leg of the incline was to be sunk from the surface 1600 ft on a 17" slope. The collar and first level at elevation 2180 ft, the second level at elevation 2000 ft, the third level at elevation 1875 ft, and the fourth level at elevation 1700 feet. From the 1700 ft elevation the incline was to flatten out to 12" for 400 ft to give the necessary depth for the ore pockets below the 1700 ft level and the necessary clearance for future sinking (see Fig 1 and 2). Due to lack of manpower in 1946, the program was changed and was as follows: A drift was driven from the old mine workings on the 1700 ft elevation in an easterly direction. At 1300 ft the drift was turned N 50" E and at this point a raise was driven 180 ft on a 50" slope. This raise intersected the Josephine horizon and commercial ore was encountered. At the 2000 ft mark, a main raise was driven, 245 ft on a 50" slope, and the 1875 ft elevation was cut. Exploration drifts were started on this level and production followed on a limited basis. The main drift at the 2500 ft point was turned N 35" E and ran parallel to and 10 ft east of and under the proposed incline line. At the proposed intersection of the drift and incline on the 1700 ft elevation, it was planned to raise the incline to intersect the 245 ft raise and to continue on to the surface, a distance of 1600 ft. When this proposed intersection point was reached, a heavy flow of water, approximately 800 gpm, was encountered and all work on the main drift face was stopped. This water flow flooded the main pump station in the old mine and the two lower levels with approximately 20,000,000 gal of water. The water was controlled and finally drained from the cave areas and lower levels after six months of pumping. After the heavy flow of water was encountered in the main heading, it was decided that the incline would have to be started from the surface, as originally planned, so that too much time would not be lost. The surface overburden had to be removed, a total of 6000 yards. A temporary dry house for 6 men was built. An 8 in. churn drill hole was intersected in the first raise driven from the 1700 foot elevation tunnel. Air and water lines were placed in this hole, and air and water were delivered to the collar of the incline from the mine working. The incline started down at 15 ft wide and 7 ft high through the Leadbetter slates. After sinking 4 sets, it was

Jan 1, 1950

By J. J. Gilman

The data presented indicate that the critical shear stress and strain-hardening Thedatapresentedrate of a zinc monocrystal depend on the orientation of its slip direction with respect to its external boundaries. The tendency of a crystal to form deformation bands also depends on its shape. THE plastic behavior of pairs of zinc monocrystals in which both members of the respective pairs had the same orientation with respect to the longitudinal axis, but each had different orientations with respect to their rectangular external shapes, were compared in this investigation. The purpose of the investigation was to see what influence the shape or surface of a zinc crystal has on its mechanical properties. In a previous investigation of triangular zinc monocrystals,1 anomalous axial twisting was observed which seemed to be related to the triangular shape of the crystals. Wolff,&apos; in 400°C tensile tests of rectangular rock-salt crystals bounded by cubic cleavage planes, found that, of the four equivalent slip systems, the two with the "shorter" slip directions yielded and produced slip lines at lower stresses than the other two. This observation and the work of Dommerich³ as formulated by Smekal4 as a "new slip condition" for rock-salt: "among two or more slip systems permitted by the shear stress law, with reference to the formation of visible slip lines by large individual glides, that slip system is preferred which has the shortest effective slip direction." More recently, Wu and Smoluchowski5 reported essentially the same effect for ribbon-like (20x2x0.2 mm) aluminum crystals at room temperature. Experimental Chemically pure zinc (99.999 pct Zn), purchased from the New Jersey Zinc Co., was the raw material. Glass envelopes, containing graphite molds and zinc, were evacuated while hot enough to outgas the graphite but not melt the zinc. At a vacuum of about 0.2 micron the envelopes were sealed off and then lowered through a furnace at 1 in. per hr so as to melt and resolidify the zinc and produce mono-crystals. One-half of one of the molds is shown in Fig. la. Each mold consisted of four pieces from a cylindrical graphite rod that was split longitudinally and transversely at its midpoints. Rectangular milled grooves 0.050 in. deep and % in. wide formed the mold cavity when the split halves were assembled with twisted wires. Fig. lb shows the specimen shape obtained when the top and bottom mold-halves were rotated 90" with respect to each other. Good fits prevented leakage and excess zinc was necessary to provide enough liquid head to fill the mold completely. In removing soft crystals from the molds it was impossible to avoid small amounts of bending. However, manipulations were carried out whenever possible with the crystals protected by grooved brass blocks. All specimens were annealed prior to testing. From the top and bottom sections of each crystal, X-ray specimens and tensile specimens 7 to 8 cm long were sawed. The tensile specimens were annealed inside evacuated tubes for 1 hr at 375°C. Next the crystals were cleaned and polished by 2-min dips in a solution of 22 pct chromic acid, 74 pct water, 2.5 pct sulphuric acid, and 1.5 pct glacial acetic acid.&apos; Cleaning was followed by a 10-sec dip in a 10 pct caustic solution, then washed in water and alcohol, and dried. This treatment results in a bright surface covered by an invisible oxide film. The testing grips were a slotted type with set screws and were supported in a V-block during the mounting operations in order to avoid bending the crystals. A schematic diagram of the recording tensile-testing machine is shown in Fig. 2. The machine has been described elsewhere.&apos; The head speed was 0.3 mm per sec for all tests. The crystal orientations were determined by the Greninger X-ray back-reflection method with an estimated accuracy of 1. Description of Crystal Geometry A schematic picture of a rectangular zinc mono-crystal is shown in Fig. 3. ABD designates the front edge of a basal plane (0001) of the crystal, the only active slip plane for zinc at room temperature. Of the three possible (2110) slip directions, the active one is indicated by an arrow. Cartesian coordinates are taken parallel to the specimen edges. The normal, n, to the basal plane (n is parallel to the hexagonal axis) has the direction cosines a, ß and ?. X0 = 90 — y is the angle between the longitudinal axis and

Jan 1, 1954

By Irving B. Cadoff, Alvin A. Machonis

The resistivity, Hall coefficient, Seebeck coefficient, and thermal conductivity were measured as a function of temperature for cation-rich alloy single crystals covering the composition range across the PbTe-SnTe system. Alloying of PbTe with up to 20 pct SnTe was found to have little effect on the energy gap. Above 20 pct SnTe the alloys were "p" type but below this range the sign could be varied by heat treatment. The lattice thermal resistivity of the compounds SnTe and PbTe is raised by alloying one with the other. Z values in the order the interesting values obtained. THE PbTe-SnTe system has several interesting features. For one, PbTe is a useful thermoelectric material and the possibility of improving its figure of merit by alloying with SnTe, an isomorphous compound, has been suggested since these pseudo-binary solid solutions generally have a more favorable ratio of electrical conductivity to thermal conductivity than either of the components.&apos; Other interesting features relate to the conductivity mechanism, band structure, and stoichiometry of the compounds and their alloys. PbTe is a semiconductor with an energy gap of about 0.29 ev2 at room temperature whose conductivity sign and magnitude can be varied from "n" to "p" by controlling the proportion of lead and tellurium with respect to the stoichiometric ratio.3 Excess lead results in "n"-type conduction. SnTe is found to exist only as a "p"-type material of relatively high conductivity. This behavior is attributed to stoichiometric deviation by Brebrick4 but Sagar and Miller proposed that the behavior of SnTe must be due in part to the presence of an overlapped band. An investigation of alloys of this system, therefore, might give additional information which would permit one to evaluate which of the two proposals is the more appropriate one. Abrikosov et al.&apos; studied the room-temperature electrical properties of these alloys and reported data for Seebeck coefficient and resistivity on poly-crystalline alloys. The present work is a more exhaustive survey of the PbTe-SnTe system. Re- sistivity, Hall coefficient, Seebeck coefficient, and thermal conductivity were measured over a wide temperature range for single crystals at 10-pct intervals of lead/tin ratio across the pseudobinary system. The relative concentration of tellurium was controlled so as to obtain metal-ion excesses in all cases. SAMPLE PREPARATION The crystals were prepared by melting elemental lead, tin, and tellurium in weighed proportions in evacuated Vycor capsules. The lead and tellurium were high-purity grades obtained from American Smelting & Refining Co. The tin was supplied by Comico. The proper calculated proportions of lead, tin, and tellurium were weighed and charged into prepared Vycor capsules prior to evacuation. The capsules were prepared from 15-mm Vycor tubing. A sharp point was worked on one end of the tube. A pyrolytic graphite coating was deposited on the Vycor walls by heating the tip to 800°C in an atmosphere of acetone-saturated argon. An additional coating of graphite was deposited on the pyrolytic coating from an Aquadag suspension. Above the coated tip the tube was reduced in diameter to form a constrictive neck. To avoid scratching the graphite coatings the charge was placed in the tube above the constriction. After a low-temperature bake, the evacuated capsule was sealed. On subsequent heating the charge melted down into the lower portion of the capsule. The crystals were grown by lowering the capsule through a Bridgman-Stockbarger furnace. The lowering rate was 1 in. per 8 hr. The upper portion of the furnace was set for 950°C and the lower portion for 800°C. In general the yield of single crystals was about 25 pct. The mixed compositions were, as expected, the most difficult to grow. The finished crystals were sectioned into 5/8-in. slices. The tip, end, and middle slices from each crystal were analyzed by X-ray fluorescence to determine the lead-to-tin ratio. The resulting values were used to plot a composition vs distance plot for each crystal. Slices were selected from each crystal, with the aid of the composition plots, to cover the complete range of compositions at 10-pct intervals. In general, the slices selected were taken from the seed end of the crystal where the longitudinal segregation (as determined from the X-ray fluorescence analysis) was a minimum. Laue single-crystal analysis and metallographic analysis was used to verify if a slice was single or polycrystal. Any grain boundaries were clearly visible in the as-cut and polished condition. In ad-

Jan 1, 1964

By S. J. Sindeband

Prior to discussing the metallurgy of sintered chromium borides, it is pertinent to outline some of the reasoning behind this investigation and the purposes underlying the work. This study was initiated as an aproach to the ubiquitous problem of a material for service at high temperatures under oxidizing atmospheres, and it was undertaken with a view to raising the 1500°F (816°C) ceiling to 2000°F (1093°C) or better. For the reason that no small, but rather a major, lifting of the high temperature working limit was being attempted, it was felt appropriate that a completely new approach be taken to this problem. A summary of the thinking behind this approach was published recently by Schwarzkopf.&apos; In briefest terms, it was postulated that the following requirements could be set up for a material which would have high strength at high temperatures. 1. The individual crystals of the material must exhibit high strength interatomic bonds. This automatically leads to consideration of highly refractory materials, since their high energy requirements for melting are related to the strength of their atom-to-atom bonds. 2. On the polycrystalline basis, high boundary strength, superimposed on the above consideration, would also be a necessity. Since this implies control of boundary conditions, the powder metallurgy approach would hold considerable promise. Such materials actually had been fabricated for a number of years, and the cemented carbide is the best example of these. Here a highly refractory crystal was carefully bonded and resulted in a material of extremely high strength. That this strength was maintained at high temperature is exhibited by the ability of the cemented carbide tool to hold an edge for extended periods of heavy service. Nowick and Machlin2,3 have analytically approached the problem of creep and stress-rupture properties at high temperature and developed procedures whereby these properties can be approximately predicted from the room temperature physical constants of a material. The most important single constant in the provision of high temperature strength and creep resistance is shown to be the Modulus of Rigidity. On this basis, they proposed that a fertile field for investigation would be that of materials similar to cemented carbides, which have Moduli of Rigidity that are among the highest recorded. The cemented carbide, however, does not have good corrosion resistance in oxidizing atmospheres and without protection could not be used in gas turbines and similar pieces of equipment. It would be necessary then to attempt the fabrication of an allied material based upon a hard crystal which had good corrosion resistance as well. It was upon these premises that the subject study was undertaken and at an early stage it was sponsored by the U.S. Navy, Office of Naval Research. Since then, it has been carried on under contract with this agency. Chromium boride provided a logical starting point for such research, since it was relatively hard, exhibited good corrosion resistance, and, in addition, was commercially available, since it had found application in hard-surfacing alloys with iron and nickel. That chromium boride did not provide a material that met the ultimate aim of the study results from factors which are subsequently discussed. This, however, does not detract from the basis on which the study was conceived, nor from the value of reporting the results which follow. Chromium Boride While work on chromium boride proper dates back to Moissan,4 there has been a dearth of literature on borides since 1906. Subsequent to Moissan, principal investigators of chromium boride were Tucker and Moody,5 Wede-kind and Fetzer,6 du Jassoneix,7,8,9 and Andrieux." These investigators were generally limited to studies of methods of producing chromium boride and detennining its properties. Some study, however, was devoted to the chromium-boron system by du Jassoneix,7 who did this chemically and metal-lographically. This system is not amenable to normal methods of analysis by virtue of the refractory nature of the alloys involved, and the difficulties of measurement and control of temperature conditions in their range. Dilatometric apparatus is nonexistent for operation at these temperatures. Du Jassoneix made use of apparent chemical differences between two phases observed under the microscope and reported the existence of two definite compounds, namely: Cr3B2 and CrB. These two compounds, he reported, had quite similar chemical characteristics, but were sufficiently different to enable him to separate them. The easiest method for producing chromium boride is apparently the thermite process, first applied by Wede-

Jan 1, 1950

By A. K. Csazar, L. W. Holm

This paper describes our investigation of a post-water-flood, oil recovery process which consists of injecting a slug of propane followed by water. Also described are the results obtained by applying a modification of the process in which gas was injected ahead of the water. Under the conditions of the latter experiments, misci-bility was not achieved between the propane and gas. Preliminary experiments or) uniform, watered-out sandstone cores showed that an oil bank could be formed and produced by applying this recovery process. However, since reservoirs are not uniform in structure, the process also was applied to porous media containing irregular porosity and to stratified sand systems. As a supplenzerrt to the experinlental work, a mathernatical procedure was developed for calculating the performance of the recovery process in a bounded, layered, porous system with crossflow between layers. As a specific example, the method was applied to predict the perforrnance of the recovery process in a 6-ft long, two-layer, stratified, unconsolidated sand model for comparison with experinlental data. The calculations were programed for the ZBM 704 computer. The equations and calcula-tional procedure presented can be extended to systems containing any number of randomly distributed permeability variations or any number of parallel layers. INTRODUCTION The problem of recovering the oil that remains in a reservoir which has been waterflooded is receiving considerable attention now as an increasing number of water floods reach an economic limit. A large number of the waterflood projects are in shallow reservoirs which are at pressures below 1,000 psi. It has been demonstrated in the laboratory that post-waterflood oil can be recover-ered by miscible displacement, but the LPG-gas, miscible flood and the enriched gas drive cannot be applied effectively at pressures below 1,000 psi. Only a few reports have appeared in the literature2-4 on low pressure, partially miscible recovery methods. However, it is possible to use LPG in a partially miscible displacement process in a reservoir where pressures of 200 to 1,000 psi can be achieved. Under these Pressures and at normal reservoir temperatures, propane is miscible with the oil; but, of course, gas or water used to drive the propane slug would not be miscible with the propane. Because of the lack of complete miscibility, it has generally been concluded that excessive amounts of propane would be required to recover oil and that such a recovery method would not be economical; however, we have found that under conditions present in certain reservoirs, an imrniscible recovery process can be applied effectively. The oil saturation in reservoirs at the economic limit of waterflood projects is usually in the range of 20 to 35 per cent of the pore space." A certain portion of this oil is left trapped by water in various size pores of the rock, but a good part of this so-called "residual" oil can be present in the less permeable lenses or layers of the reservoir rock which were by-passed to some degree by the water. The oil in these permeability traps can be produced only if favorable pressure gradients are formed in the reservoirs between adjacent zones of high and low permeabilities. A low viscosity liquid, miscible with the oil in place, which is driven by water through a stratified or heterogeneous porous system can aid in the development of these favorable pressure gradients. The oil that is released thereby from the permeability traps can be recovered by the subsequent water flood. Studies were made to determine how much oil could be recovered from homogeneous and stratified cores and models, which had been water flooded, by injecting a slug of propane and driving it with water. The effect of injecting a slug of gas ahead of the water was also determined. Most of the work described herein was done with the propane-water combination; unless otherwise specified, no gas was injected. The principal objectives of the investigation were to determine (1) if an oil bank could be formed and (2) what ratio of oil recovered to propane injected would be obtained. A further objective was to develop a method for calculating fluid-flow performance in stratified systems which would account for fluid transfer between zones in hydrodynamic communication but of different permeabilities. THEORETICAL ANALYSIS In a theoretical study of the recovery process, analytical expressions were derived to calculate the pressure distribution, the fluid flux in longitudinal (parallel to layers) and transversal (across the layers) directions, and the fluid distribution at any point in the system. The equations were developed for a two-layer porous system in which it was assumed that the fluids in the system were incompressible and that capillary and gravity effects were

By B. G. Matson, M. A. Whitfield, G. R. Dysart

This paper describes the development of u computer program to calculate changes that occur in the length of tubular goods due to temperature and pressure changes during stimulation operations. Due to the numerous variables involved and the uncertainty of all static and dynamic conditions that could exist, it becomes a staggering task for individuals charged with completions to perform the necessary mathematical calculations. The computer program permits advance calculations for several sets of conditions. INTRODUCTION In the Delaware basin of West Texas alone, 50 wells were contracted or drilled to 15,000 ft or deeper in 1965. Deep well activity is continuing in this and other areas on an expanding scale. Many of these deep wells require extensive stimulation for successful commercial production, and during these operations, pressures and temperatures are encountered that have a pronounced effect on the length of tubular goods. This length change during a large-volume, high-pressure stimulation treatment utilizing fluids considerably cooler than bottom-hole temperature can be of such a magnitude that permanent damage to casing and tubing will result unless mechanical design, pressures and fluid temperatures are evaluated and controlled. These pressure and temperature effects can be calculated. However, the process lends itself well to computer solutions because of the mathematical nature of the problem and the calculating hours involved in arriving at an answer. The engineering-hour demand becomes more severe as tapered strings are involved. On initial treatments on a given well, surface pressure and injection rate conditions are unknown, and offset well conditions have not proven to be a reliable method for making predictions. For these reasons, it has become rather standard procedure for operators to compensate for these uncertainties by placing unnecessary pressure and fluid temperature restrictions on stimulation design. On a number of occasions treating fluids have been preheated to as much as 160F as a means of compensating for thermal contmction resulting from pumping cool fluids. The maintenance of packer seals has been treated by Lubinski, Althouse and Logan&apos;,&apos; and the problem of therma1 effects on pipe has been explored by Ramey." These works were expanded and the results made applicable to everyday oilfield terminology before submitting them to computer programming. The pressure and temperature effects on tubing movement previously mentioned occur simultaneously as fluid moves through the pipe. The pressure changes, for purposes of explanation, are categorized here as to the various effects these pressures have on a tubing string. These divisions are (1) the piston-like results of forces acting on horizontal surfaces exposed to pressure, (2) swelling or ballooning of the tubing along its entire length due to the forces of pressure acting against the tubing walls, (3) the elongation of tubing due to frictional drag and (4) corkscrewing of the pipe due to internal pressure. Thermal changes are also of great importance, as their results may be more significant than any of the pressure effects. Steel is an excellent conductor of heat and the earth is a relatively poor conductor. It has been calculated that pipe temperatures at depths of more than 20,000 ft approach within as little as 25" the temperfature of the surface fluid after pumping for 2 hours, or a drop in temperature in some treatments of more than 220F. The equations presented in this paper were developed for computer programming and simplicity of input information; therefore, numerical constants such as Young&apos;s modulus for steel (28 X 10\ si), the coefficient of thermal expansion of steel (6.9 X 10."IF) and Poisson&apos;s ratio for steel (0.3) are included with unit conversion factors. The moment of inertia of tubing cross-sectional area with respect to its diameter was changed to a constant times (D&apos; — d&apos;) where D is outer diameter and d is inner diameter. Units in the equations are length in feet, diameter in inches, density in pounds per gallon, pressure in psi, rate in barrels per minute and time in hours. PISTON-LIKE REACTIONS A change in tubing internal dimensions and the exposure of other horizontal surfaces to different pressures on the inside and outside of the tubing result in a reaction much like a piston under pressure. Such is the case when the internal diameter changes in a combination string of pipe, when seals of a slick joint assembly are subject to pressure and in the end effects of a tubing string. The change in tubing length due to the piston effects of a slick joint packer is affected by the various diameters involved, the tubing pressure Ap,, the casing pressure ,Ap,, length of pipe L, densities of fluid in the tubing before and during pump-

By C. Gatlin, F. Armstrong, K. E. Gray

This paper presents some preliminary results of two-dimensional cutting tests of dry limestone samples at utmospheric pressure. Cutting tips having rake angles of + 30°, + 15", 0°, - 15" and - 30" were used to make cuts on Leuders limestone samples at six depths of cut ranging from .005 to ,060 in. at cutting speeds of 15, 50, 109 and 150 ft/min. The vertical and horizontal force components on the cutting tips were recorded with an oscilloscope equipped with a polaroid camera. Motion pictures of the cutting process at camera speeds of 5,000 to 8,000 frames/sec were taken at strategic points in the variable ranges. The movies provide considerable insight into the brittle failure mechanism in rocks. It appears that chip-generating cracks usually have an initial orientation which is related to the resultant of the externally applied forces. The latter part of the crack curves upward toward the free surface being cut, this part being governed by some type of cantilever bending or prying. The linear and angular motion of the loosened chips also indicate the tensile nature of brittle failure. Analyses of the forces on the cutting tips indicate that: (I) relatively small increases in vertical loading result in large cut-depth increases for sharp tips (rake angles 2 0"); (2) tool forces increase at an increasing rate as the rake angle decreases, particularly for rake angles < 0"; and (3), for the range of this study, rate of loading had little effect on the maximum forces. Both the movies and visual inspection of the cuttings indicated that the volume of rock removed by chipping was much larger than that by any grinding mechanism, even for tips having negative rake angles. Cutting size increases with increased cut depth and rake angles, and decreases slightly at high cutting speeds, the depth of cut having by far the most influence. The amount of contact between the rock and the cutting tip was always less than the depth of cut and rarely exceeded 0.010 in. even for cuts of 0.060 in. INTRODUCTION The planing (or slicing) of various materials with a fixed blade has long been practiced by workers in many industries. For example, the farmer&apos;s plow, the carpenter&apos;s plane and the housewife&apos;s paring knife all employ this basic action. The casual observer might suspect that something so common must be quite simple; however, as in all problems involving the failure of materials, such is not the case. Industries concerned with the machining of metals have long studied these problems, and their literature on the subject is voluminous. Despite these efforts, basic knowledge is not very advanced, as may be noted from recent and comprehensive analyses of their literature.12 Metals are more subject to analysis by classical theories of elasticity and/or plasticity than are rocks, since their elastic constants and strengths are reasonably well established in many cases. In spite of this relative "simplicity", Hill9 refaces his discussion with an admission that the mathematical solution to the machining problem is not known. Photoelastic studies of both machining and milling have been performed and are discussed thoroughly by Coker and Filon.4 Rotary drilling of rocks with fixed blade or drag bits has long been practiced by the mining and petroleum industries, and considerable study has been given to defining their cutting action in terms of the pertinent variables. Essentially all the published mechanistic research on drag-bit drilling has been performed by mining engineers and has been concerned only with rocks in the brittle state. Fairhurst5-7 has worked extensively in this area and employed photographic techniques quite similar to those reported here, except at much lower speeds. His studies showed the periodic or cyclical nature of the brittle failure mechanism, in which instantaneous loads on the bit varied from some maximum value to near zero. Goodrichs has presented further data on the subject as well as a qualitative description of the process. Again the postulated mechanism is cyclical, with alternate chipping and grinding periods. The ploughing of coal is a practiced method and has been studied in some detail by English mining engineers."" Their findings have considerable general application to drag-bit drilling. Evans," in particular, has extended Merchant&apos;s metal-cutting theory" to brittle materials with some success, although certain aspects of his theory are open to question. Fish13 has recently summarized nearly all the published works concern-

By D. Kunstelj, M. Stubicar, A. Tonejc, A. Bonefacic

A. Bonefafcic, D. Kunsfeli, M. Stubicar, and A. Tonejc The present communication is concerned with the variation of the texture in aluminum wires with die angle and temperature, at constant speed of extrusion. Experiments were carried out concurrently on refined samples, with a stated purity of 99.997 pct pure A1 and commercial samples of 99.5 pct Al. Ingots of refined aluminum samples were machined to 30-mm-diam by 150-mm-long billets. These billets were transformed to 5-mm-diam wires by drawing. The final form, suitable for examination, was obtained by extrusion through conical-face dies with a 1-mm hole diam and extrusion ratio 5:l in diam. The initial form of the commercial aluminum samples was drawn wire 5 mm in diam. These samples showed a poorly defined texture with (111) as a major and (001) as a minor component. A similar defined texture appeared in the refined aluminum samples after drawing to 5 mm diam. Conical-face dies with different angles (defined by the axis and the generating line of the cone) were used in our experiments. The values of the angles were 27, 35, 45, 57, 63, and 90 deg. The extrusion container was fitted with a heating element and controller permitting temperatures up to 600°C to be maintained within i5"C. Extrusion was performed at 250°, 300°, 350°, 400°, and 500°C at constant speed (approximately 1 mm per sec) and constant die reduction. The extrusion product was a wire 1 mm in diam and approximately 20 cm long. In order to remove the surface layer with the "conical" texture and to reduce the absorption by the X-ray examination of the samples, the extruded wire was etched to 0.22 mm in diam. Experiments were performed in the middle sections of the 20-cm-long wires. In addition to the die of l-mm hole diam, dies with a 1.5-, 0.7-, 0.6-, 0.5-, and 0.4-mm hole diam and 63-deg die angle were constructed. In our experiments we did not find in these ranges any important difference concerning the texture of the extruded wires and we continued our work solely on the 1.0-mm die. The diffracted X-rays (Cu K radiation) were recorded photographically. Diffracted intensities were measured on the (111) reflection with a microphotometer. The relative amounts of texture components were determined from the areas under the diffracted maxima. We found the texture of extruded aluminum wires to be strongly influenced not only by the temperature of extrusion and the purity of the sample but also by the form of the die. It is generally admitted that cold-drawn aluminum wires have mainly a (111) texture with a small amount of (001) component, Table I of Ref. 1. In our experiments with wires extruded in conditions represented by Fig. 1, in some cases a single (001) texture was obtained. If these wires were drawn repeatedly at room temperature, X-ray measurements revealed a duplex (001)-(111) fiber texture. Further drawings increased the (111) and decreased the (001) texture component. In Fig. 1 the percentage of material oriented with (001) parallel to the extrusion direction is represented as a function of the temperature and the die angle (a), for commercial and refined aluminum samples, respectively. From these diagrams we may draw the following conclusions. The slope of the die (a) influenced more strongly the texture at the lower rather than the higher temperatures. Again, a stronger influence was found in the case of the commercial in comparison with refined aluminum samples. In the case of the commercial aluminum samples the amount of material with (001) texture increases with increasing wire temperature in an approximately linear manner. This effect is less pronounced in the pure aluminum samples, with the exception of the die with a = 45 deg. In this case the (001) texture decreases with increasing temperature, as shown in Fig. 1. Component (001) is more pronounced in higher-purity aluminum samples. Our experiments led to the conclusion that both (001) and (111) components are essentially stable in extruded aluminum wires. As we obtained a single (001) texture starting with a sample of drawn wire in which the (001) component was very weak, our experiments revealed that the (001) component is not a remnant of the initial texture; this is in disagreement with the findings of Vandermeer and McHargue.1 We gratefully acknowledge discussions with Professor M. Paic. 1 R. A. Vandermeer and C. J. McHargue: Trans. 7MS-AME, 1964, vol. 230, p. 667.

Jan 1, 1969

By E. W. Filer, L. S. Darker

ONE of the primary purposes of this investigation was to determine how far blast-furnace metal and slag depart from equilibrium, particularly with respect to sulphur distribution. In studying the equilibrium between blast-furnace metal and slag, there are two approaches that can be used. One method is to use synthetic slags, as was done by Hatch and Chipman;&apos; the other is to equilibrate the metal and slag from the blast furnace by remelting in the laboratory. In the set of experiments here reported, metal and slag tapped simultaneously from the same blast furnace were used for all the runs. The experiments were divided into two groups: 1—a time series at each of three different temperatures to determine the t.ime required for metal and slag to equilibrate in various respects under the experimental conditions of remelting, and 2—an addition series to determine the effect of additions to the slag on the equilibrium between the metal and slag. An atmosphere of carbon monoxide was used to simulate blastfurnace conditions. The furnace used for this investigation was a vertically mounted tubular Globar type with two concentric porcelain tubes inside the heating element. The control couple was located between the two porcelain tubes. The carbon monoxide atmosphere was introduced through a mercury seal at the bottom of the inner tube. On top, a glass head (with ground joint) provided access for samples and a long outlet tube prevented air from sucking back into the furnace. The charge used was iron 6 g, slag 5 g for the time series, or iron 9 g, slag 7 % g for the addition series. This slag-to-metal ratio of 0.83 approximates the average for blast-furnace practice, which commonly ranges from about 0.6 to 1.1. A crucible of AUC graphite containing the above charge was suspended by a molybdenum wire in the head and, after flush, was lowered to the center of the furnace as shown in Fig. 1. The cylindrical crucible was 2 in. long x % in. OD. The furnace was held within &3"C of the desired temperature for all the runs. The temperature was checked after the end of each run by flushing the inner tube with air and placing a platinum-platinum-10 pct rhodium thermocouple in the position previously occupied by the crucible; the temperature of the majority of the runs was much closer than the deviation specified above. The couple was checked against a standard couple which had been calibrated at the gold and palladium points, and against a Bureau of Standards couple. The carbon monoxide atmosphere was prepared by passing COz over granular graphite at about 1200°C. It was purified by bubbling through a 30 pct aqueous solution of potassium hydroxide and passing through ascarite and phosphorus pentoxide. The train and connections were all glass except for a few butt joints where rubber tubing was used for flexibility. The rate of gas flow was 25 to 40 cc per min. As atmospheric pressure prevailed in the furnace, the pressure of carbon monoxide was only slightly higher than the partial pressure thereof in the bosh and hearth zones of a blast furnace—by virtue of the elevated total pressure therein. Simultaneous samples of blast-furnace metal and slag were taken for these remelting experiments. The composition of each is given in the first line of Table I. There is considerable uncertainty as to the significant temperature in a blast furnace at which to compare experimental results. This uncertainty arises not only from lack of temperature measurements in the furnace, but also from lack of knowledge of the zone where the slag-metal reactions occur. (Do they occur principally at the slag-metal interface in the crucible, or as the metal is descending through the slag, or even higher as slag and metal are splashing over the coke?) The known temperatures are those of the metal at cast, which averages about 2600°F, and of the cast or flush slag, which is usually about 100°F hotter. To bridge this uncertainty, remelting temperatures were chosen as 1400°, 1500" (2732°F), and 1600°C. For the time series the duration of remelt was 1, 2, 4, 8, 17, or 66 hr; crucible and contents were quenched in brine. The addition series were quenched by rapidly transferring the crucible and contents from the furnace to a close-fitting copper "mold." Of incidental interest here is the fact that the slag wet the crucible

Jan 1, 1953

By C. W. Sherman, N. J. Grant

The correlation of the high temperature chemical properties of slag-metal systems with some easily measured property of either slag or metal at room temperature has been the goal of both process metallurgists and melting operators for many years. There are several rapid methods for estimating various constituents in steel in addition to the conventional chemical methods which are quite fast, but these do not reveal the nature of the slag as a refining agent, which is of primary interest to the steelmaker. Furthermore, there are several methods for examining slag, the three principal ones being slag pancake, petrographic examination, and the previously mentioned chemical analysis. The main objection to the last two is the lime required to make a satisfactory estimate of the mineralogical or chemical components. The objection to the first is the inadequacy of the information obtained. A new technique has been developed by Philbrook, Jolly and Henry1 whereby the properties of slags are evaluated from an aqueous solution leached from a finely divided sample of slag. It is known that the pH or hydrogen ion concentration (of saturated solutions that have dissolved certain basic oxides, notably calcium oxide) will indicate a pronounced basicity. Philbrook, Jolly and Henry devised the pH measurement technique in order to supply open hearth operators with a fast, reasonably accurate method of estimating slag basicity. They offered the method as an empirical observation and made no claims as to its theoretical justification. The results were presented as an experi-metally observed relationship which applied over an important range of basic open hearth slags. They found that, in plotting the measured pH against the basicity, the best relationship existed between the pH and the log of the simple V ratio, CaO/SiO2. Extensive investigation also showed that there were several variables in the experimental technique that influenced the results and necessitated following a standard procedure to obtain reproducible pH readings. These variables were: 1. Particle size of the slag powder used. 2. Weight of sample used per given volume of water. 3. Time of shaking and standing allowed before the pH was measured. 4. Exclusion of free access of atmospheric carbon dioxide to the suspension. 5. Temperature of the extract at the time the pH was measured. In subsequent investigations of the pH method by Tenenbaum and Brown2 and by Smith, Monaghan and Hay3 the general conclusions of Philbrook&apos;s work were reaffirmed. It was the object of the present investigation to extend the technique to a point where it could be used to evaluate slags of all types. Experimental Results PARTICLE SIZK OF SLAG POWDER A large sample of commercial blast furnace slag of intermediate basicity (V-ratio 1.15) was selected for the study. The slag had been put through a jaw crusher until all of it passed through a 20 mesh screen. Five fractions of this crushed material were separated, -20 to +40, -40 to +60, -60 to +100, -100 to +200, and -200 mesh. A representative sample of 0.5 g was removed from each fraction and the pH determined using the method of Philbrook. Check pH analyses on the sample fractions varied due to the different amounts of shaking. To eliminate this variable, a mechanical shaker was employed. In order to know the exact time of contact between the slag and water, it was found necessary to filter the extract at the end of the shaking period. Using the mechanical shaker and a filtering apparatus, similar runs were made on the five fractions for contact times of 5, 10, 20, and 40 min. Random checks gave reproducible results within 0.02 pH. The data are plotted in Fig 1. It can be seen from the plot that each slag fraction is hydrolyzed to an extent that is roughly proportional to the surface area exposed to the water. The (—100 to +200) mesh material changed very little in pH after 10 min. shaking time. The curves are symmetrical and lie in proper relation to one another. The —200 mesh curve appears to be somewhat flatter than the others, but this can be attributed to the portion of very fine material that is not present in the other fractions. The closeness of the (-100 to +200) mesh curve to the —200 mesh curve and the fact that a —100 mesh sample would contain amounts of slag down to 1 or 2 microns in diam were considered sufficient reasons for selecting a —100 mesh sample as representative of the whole sample of slag for the purposes of this investigation.

Jan 1, 1950

By D. J. McAdam

In a series of papers the author and associates have discussed the influence of temperature on the tensile properties of metals.11-18 These papers present much information about the influence of temperature and the stress system on the conventional indices of mechanical properties, with special attention to the fracture stress. A recent study of the data, however, has revealed much additional information about the influence of temperature on the fundamental factors involved in the flow of metals. The present paper presents results of this study. Attention will be confined almost entirely to results derived from tension tests of unnotched cylindrical specimens at strain rates a little slower than those used in ordinary tension tests. According to a concept first presented by Ludwik and elaborated in recent papers by others,8,9,22,23 the mechanical state of a metal depends on the total plastic strain, but not on the temperature during straining, provided that the only structural changes are those essential to plastic deformation. In the summer of 1948, however, the author made the previously mentioned study of results of a general investigation by the author and associates and reached the conclusion that the mechanical state depends not only on the total strain, but also on the temperature during the straining. A number of diagrams were then prepared. These conclusions were presented without diagrams in a discussion last October of a paper by Dorn, Goldberg and Tietz.2 The metals used in the investigation on which this paper is based were Monel and oxygen-free copper. The Monel was supplied by the International Nickel Co. through the courtesy of Dr. W. A. Mudge. The copper was supplied by the Scomet Engineering Co. through the courtesy of Dr. Sidney Rolle. The data to be presented are based on results of tests at temperatures ranging between 165 and — 188°C. Description of the apparatus and methods of test are given in previous papers.1011&apos;1"2 The present paper is the first part of the general discussion of the influence to temperature on the stress-strain-energy relationship for metals. The next paper will deal with metals that are subject to structural changes other than those induced solely by plastic deformation. Influence of Temperature and Plastic Strain on the Flow Stress of Monel and Copper For a study of the influence of temperature on the stress-strain relationship, flow-stress curves obtained with annealed metals at various temperatures will be compared with curves obtained with the same metals after cold drawing or cold rolling at room temperature. Diagrams thus obtained with Monel and copper are shown in Fig 1 to 8. Fig 1 to 7 show the variation of the flow stress with temperature and plastic strain; Fig 8 is a diagram of a different type, derived from Fig 4 to 7. In Fig 1 to 7 strain is expressed in terms of A0/A, in which A0, and A represent the initial and current areas of cross-section. Since values of Ao/A are represented on a logarithmic scale, abscissas are proportional to true strains; moreover, the true strains representing prior plastic deformation and those representing subsequent strain during a tension test are directly additive. Fig 1 shows flow-stress curves obtained with annealed Monel. Five of the curves are based on results of tension tests. Between yield and the maximum load, the flow was under longitudinal tensile stress; between the maximum load and fracture, the local contraction induced transverse radial tensile stress. The portions of curves designated F, therefore, represent flow with increasing radial stress ratio, the ratio of the transverse stress S3 to the longitudinal stress Si. Curve Fo is based on the ultimate stresses of specimens taken from bars that had been cold drawn various amounts.17 Since the tensile stress at the maximum load is unidirectional, curve Fo represents the course that a flow-stress curve would take if the stress during an entire tension test could be kept unidirectional. The flow-stress curve F obtained at room temperature (Fig 1) has been established accurately by numerous measurements of the diameter of the specimen during the extension from yield to fracture.17 At the time of the experiments, however, no apparatus was available for measuring the diameter during tension tests at low temperatures. Nevertheless, curves have been established to represent with sufficient accuracy the flow at low temperatures. Each flow-stress curve must be tangent to a curve U, which starts at a point representing the ultimate stress of annealed metal. Since the ultimate stress is based on the area of

Jan 1, 1950

By Lee Hillard Meltzer, Ralph E. Davis

INTRODUCTION During the past few years emphasis has been placed upon methods of estimating the future expectancy of gas production from natural gas fields. Before technical methods were applied, the production expectancy over future years was based upon the knowledge of gas well behavior, learned through long experience and embedded in the "know-how" of men long in the gas producing business. It is doubtful that a technical study of future expectancy of a gas field or a group of fields was ever prepared for the preliminary planning of a natural gas pipe line system built prior to about five years ago. The decline in well production capacity was naturally recognized by all familiar with the business since its earliest beginnings more than 75 years ago. In 1953, the Bureau of Mines published Monograph Number 7, "Back-Pressure Data on Natural Gas Wells and Their Application to Production Practices," which gave to the industry the first technical analysis of the decline in production of individual gas wells. This method affords a means of estimating the future production in relation to decline in reservoir pressure. The demand for technical determination of expectancy of future gas productivity from fields or a group of fields led technical men to the application of the knowledge of well behavior to the problems. The decline in a well&apos;s ability to produce as pressures declined could be estimated by the use of the curve known as the "back-pressure potential curve" as developed by the Bureau of Mines. A field containing few, or even numerous, wells could be analyzed on the basis of the sum of potentials of all wells. In most studies of this nature, the problem is to estimate the rate of production that can be expected, not only from present wells but also, from wells that will in the future have to be drilled into the reservoir being studied. The "back-pressure potential" method requires that the following data be known or estimated: (1) Proved gas reserves. (2) Current shut-in pressures and rate at which shut-in pressures change with production. (3) Back pressure potential data on wells in the source of supply. (4) Ultimate number of wells which will supply gas, and their potential. (5) Limitations on productivity such as line pressures against which the wells will produce, friction drop in the producing string, and so forth. It is evident that the resulting estimate of gas available in each year for a future of say, 20 years, contains many uncertainties. While the method may have considerable merit for a field that is fully developed, it cannot be completely dependable in fields that are only partially developed. In such cases, some of the data upon which it is based can only be estimated or assumed. In the study of this problem during the past few years, a method has been developed which we believe has great merit, especially when applied to fields subject to substantial future drilling, and when applied to the study of fields which, on the average, appear to have characteristics similar, in general, to the average of the fields used in the development of the "yardstick" outlined herein. From an analysis of the production history of 49 reservoirs which are depleted, or nearly depleted, a curve has been constructed which shows the average performance of the reservoirs during the declining stages of production. When properly applied, this "average performance curve" can be used to determine the stage of depletion at which a reservoir or group of reservoirs will no longer be able to yield a given percentage of the original reserves. "AVAILABILITY" AND "AVAILABILITY STUDIES" The rate at which. a reservoir will yield its gas depends basically upon physical factors, such as the thickness and permeability of the sand, the effect of water drive, if any, and other conditions, and upon economic factors, such as the number of wells drilled. Within the ranges set by the physical conditions, a rate of delivery tends finally to become established. The rate (or range of rates) represents a balance between the interests of the operator, who desires the maximum return from his property and of the pipe line owner, who desires to maintain a firm supply for his market. This balance, which is influenced by the terms of the contract, determines the capacity which will be developed by the operator, and the time and rate at which the decline in production is permitted to occur. Thus the "availability" of gas

Jan 1, 1953

By J. F. Myers, F. M. Lewis

DISCUSSION L. E. Djingheuzian (Canadian Dept. of Mines and Technical Surveys, Ottawa)—In their Summary the authors say: "Reconciling the grinding efficiency with good metallurgy is still a problem." In the discussion of the first paper8 in his reply to W. I. Garms, Mr. Myers states: "Our grinding process with smooth I-in. balls has reduced by nearly one half the metallic losses in the fine micron sizes of the tailing. This is simply because less of the fine micron sizes are produced. Since the + 65 mesh size is the same as formerly, a higher percentage of the intermediate sizes are developed. These sizes have the highest floatability, require the least reagents, and use less floating time. "These factors contribute so heavily to the overall economies that dropping our power grinding gain from 28 pct back to 19 pct is a small detail. However, we feel that this is only a momentary situation and that eventually the best features of the grinding and flotation processes can be brought together, which is as it should be." Italics are mine. The above statements, to me, appear to be the answer to the opening statement in the Summary. Denoting the costs at different power grinding gains as: Power Grinding Power Grinding Gain, 28 Pct Gala, 19 Pct Cost of grinding G G1 Cost of flotation F F1 Value of metallic losses T T1 where G1 > G2 F3 < F, and T1 < T, we have: G1+Fl+T1<G +F+T. Since the authors accept the idea that "grinding in flotation plants becomes part of the &apos;conditioning&apos; of the feed to flotation",4 i.e., that in flotation the ball mill is primarily a conditioning machine, it can be postulated that Tennessee Copper grinding at cost G1 is more efficient than grinding at lower cost G. This can be directly inferred from the Conclusion of the paper. Mr. Myers also emphasizes this at the end of his reply to Mr. Garms: "that grinding is for the purpose of preparing flotation feed and not grinding per se." This, to me, in the final analysis means that when the efficiency of grinding is weighted against the conditioning factor, the former becomes a function of efficient conditioning, hence, within the system in which proper conditioning is the dominant factor, the best grinding efficiency is provided by grinding which will contribute towards the optimum conditioning. This brings us again to the statement: "that if every grinding unit were considered as a conditioner for each following step, efficient grinding plants would become much easier to design."&apos; In other words, grinding equipment should be balanced against the flotation equipment and against chemical reactions taking place in the system. F. C. Bond (Allis-Chalmers Mfg. Co., Milwaukee)— The authors&apos; discussion of the probable ball motion in a slow speed high dilution mill is very interesting. When the 1-in. balls have worn down to about one fourth of their original weight they apparently first develop a flat surface; as wear progresses this flat face becomes concave, and other concave faces appear. It seems more probable that the first flat face may form at the softest part of the ball surface, and that each succeeding contact tends to force this flat face into sliding contact with a larger round ball; than that the flat faced ball tends to pair off with a particular round ball and to travel with it continuously. When the small worn ball has a flat face and is in sliding contact with a large round ball, the surrounding large balls will assume a more or less definite pattern, and slide against the worn ball, thus producing secondary concave faces. The primary concave face seems to be larger and better developed than the secondary faces. The ball charge can be divided into "concaves" which show at least one concave surface, "intermediates" which have developed flats or incipient concaves, and "rounds." Ball slippage is always present in a tumbling mill, and the mutual ball movement is necessarily a combination of rolling and sliding. The sliding motion is apparently concentrated upon the smaller worn balls which nest between the surrounding larger round balls. When each worn ball starts its upward path in the mill its primary flat or concave surface fits against a larger round ball, and the round ball slides upon it. The action may be something like that of the ball separator in a ball bearing, except that the worn sliding balls are always under considerable pressure. The material is ground under the combined influence of breakage 1—by impacts between falling balls and between falling and supported balls, 2—by being nipped between rolling balls, and 3—by being rubbed between the sliding balls. The rubbing action will be increased in the presence of worn balls with concave surfaces. The rubbing action probably produces a considerable portion of the finely ground slimes in the product. The worn balls commonly approach tetrahedrons in shape, and are very different from concavex, each of which has two equal opposed concave surfaces. Concavex were designed only to grind upon themselves, and not for use in combination with grinding balls. Their action in a grinding charge is very different from

Jan 1, 1952

By T. F. McCormick

THIS year, 1950, is the golden anniversary of the construction and operation in this country of a tube mill for the sole purpose of fabricating aluminum alloy tubing. For a short period prior to the beginning of this mill, aluminum alloy tubing was obtained from foreign sources or produced in mills fabricating other metals. Indeed, it was a very short period because aluminum itself was a newcomer in the field of metals. The first sheet rolling mill had been in operation just eight years and a rod rolling mill for the production of wire and cable had been functioning one year. The first tube mill for aluminum was built by the Aluminum Co. of America in May 1900 and started production with four draw benches and five men, including the mill superintendent. The building itself was a lean-to attached to a sheet-rolling mill at New Kensington, Pa. The cost of equipment, including the draw benches, dies, mandrels, and other tools, was about $5000. This figure seems absurd in the present day but nevertheless it was questioned at that time whether or not such a large sum should be spent to embark on a new and uncertain venture. The initial production system for the new mill consisted of casting round hollow ingots in a tilting-type iron mold, reducing the ingots to bloom size outside the plant, and finally drawing to size on the draw benches. This method of producing aluminum alloy tubing survived just two years, as blooms of satisfactory quality were not obtained consistently. It was superseded by the cupping method in which a 24-in. diam circle cut from a rolled plate was formed into a tube bloom using first a small cupping press and then a push bench. It was stated that tubing so produced was limited to a maximum diameter of 2 3/4 in. and to wall thicknesses varying from 12 to 24 gage. However, for the first time all the operations were performed at one plant and the result was a quality product. Later larger cupping presses and push benches were obtained and the method continued to be the principal one for aluminum alloy tubing for almost a quarter of a century. During the interim the use of a Alan Mannesmann -type billet piercer was explored and it was used to some extent, but failed to produce consistently a smooth inside surface suitable for drawing with aluminum alloys. Experiments started during the latter stages of World War I in the production of tube blooms with a hydraulic extrusion press, led to the use of this type of equipment to make tube blooms for further drawing during a change-over period extending from 1925 until 1930. At this time the cupping method was discarded completely. From these humble beginnings, the aluminum alloy tubing business expanded until well over six million pounds were produced in a single month in the United States during World War II. The major portion of this production was in strong alloys which did not appear in the tubing picture until 1022, when 17S alloy tubing was introduced for aircraft construction.

Jan 1, 1951

By C. J. Sparks, J. C. Ogle, E. A. Starke

DEFORMATION of cold-rolled fcc metals and alloys produces one or the other of two types of rolling textures, usually referred to as the copper type or the brass type. The pure fcc metals, with the exception of silver, develop the copper-type texture when rolled at room temperature. Silver, brass, and many other alloys develop the brass-type texture. Transition from one texture type to another can also occur. Solute additions to pure copper cause a transition from the copper-type to the brass-type texture.&apos; Varying the deformation temperature also produces texture transitions. Copper rolled at -196°C developed the brass-type texture2 and silver rolled at elevated temperatures, 200°C, developed the copper-type texture.374 The work of Haessner,&apos; Smallman and Green,6 and Hu and coworkers3&apos;4 seems to have established an apparent correlation between the type of rolling texture (and the texture transition) and the stacking-fault probability. Thus materials with low stacking-fault energies are thought to develop the brass-type texture while high stacking-fault energy materials develop the copper-type texture. Mikkola and cohen7 measured by X-ray diffraction techniques the stacking-fault probability, a, in the ordered and disordered fcc alloy Cu3Au. Unexpectedly, ordered specimens showed about twice the stacking-fault probability as the disordered ones. Marcinkowski and Zwe118 also found stacking faults in ordered Cu,Au, but not in the disordered CusAu. More recently, Camanzi and coworkers9 have shown that the intrinsic stacking-fault energy of Cu3Au undergoes a considerable decrease (approximately 100 ergs per sq cm) when passing from the disordered to the ordered phase. In general, deformation reduces order&apos;&apos; but some of our measurements showed that some long-range order still remains in Cu3Au after cold reduction by rolling 80 pct. From the above considerations Cu3Au offers the possibility of studying the texture transition in fcc alloys without varying either the temperature or the composition. If the stacking-fault energy correlation is correct, an initially ordered alloy should develop the brass-type texture during rolling while a disordered alloy should develop the copper-type texture. The present communication describes some initial results of experiments designed to investigate this possibility. The rolling textures of ordered and disordered Cu3Au samples were determined after various amounts of deformation. The ordered sample had an initial long-range-order parameter of S = 1, determined from X-ray diffraction. The grain size of both the ordered and disordered samples was the same, and the initial textures of both were also identical and approximately random. No obvious differences in the deformation textures of the ordered and disordered materials were detected up to 35 pct reduction and the (111) pole figures of Fig. 1 resemble that of pure copper. However, with reduction larger than 35 pct and less than 50 pct, a marked deviation from the copper texture was noted in the ordered material. The newly developed orientation was close to the (110)[i12] ideal orientations re-

Jan 1, 1970

By S. S. Clarke

Late in 1942, the increasing demand for zinc, coupled with the growing shortage of miners and the knowledge that some abandoned mines would have to be reopened for prospecting and development, led to considerable thought as to the possibilities of further mechanization in order to conserve man power. The ore bodies, locally termed "sheet ground," are an important ore bed in some mines and are in the lower part of Boone formation of the Mississippian Series. Some mines contain interbedded layers of nearly pure galena and sphalerite in horizontal sheets ranging in thickness from a thin seam to several inches and is persistent over large areas. This type of ore body offered the best opportunity for study and experiments. The use of Jumbo drill carriers was advanced but some doubt was expressed as to the adaptability of Jumbos as then in use to mine headings as compared to post and arm mounting (Fig I). Another consideration was the introduction of truck haulage when several mines were trackless. A drill frame, built to carry 2 4-in. drifters, was mounted on a truck chassis. This design proved a failure as it was not rigid and the resiliency of the tires and springs allowed too much play. Long screw jacks were then used to hold the truck firmly in place, but placing the jacks and securing the truck required more effort and time than setting up post drills, so the truck carrier was abandoned. The use of a bull dozer underground had been under consideration for some time to be used in "brunoing" the broken dirt from behind pillars and other inaccessable places so the slusher drags could load without double dragging the dirt. A dozer with hydraulic blade lift was purchased and R. I. Tuthill, Superintendent of Section 30 Mines, suggested that a long drill arm be substituted for the blade, and the drills mounted on the cross member. The hydraulic lift would permit drilling holes at any required spacing. The "cat" was very mobile and answered the problem of a trackless mine. The initial tests showed that the "cat" would make a good carrier, but the hydraulic controls were not positive enough to keep the drills in alignment while drilling. The next step was to build a small hoist. This hoist was attached to the power take-off on the "cat" and by means of sheaves and a double line of 3/8-in. hoist cable, a positive control for raising and lowering the boom was obtained. To avoid serious injuries to the drillers should the cable break, a safety chain was fastened to the drill boom and hooked into a slot in the back of the "cat" frame. A different power unit was obtained for the "cat," as a state law prohibited the use of internal combustion engines in mines. A custom machine shop had just placed on the market a small hoist powered by a Model A Ford engine that had been very ingeniously converted to a slide valve engine using compressed air. To use this unit on a "cat," our master mechanic de-

Jan 1, 1949