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By C. A. Doh, R. Q. Fields, M. Lebourg

A formation tester run on logging cable is now available to the oil industry. It offers a method of safely and rapidly testing possible producing formations in uncased holes. These tests can be made up the hole after running the electric log. Reservoir pressure data is continuously recorded at the surface as the fluid sample is extracted. The tester may be assembled with a reservoir of 1-, 2.75-, or 5.5-gal capacity. A retaining pad on the body of the tool is expanded against the wall of the hole at the exact depth desired; this depth is determined by electrical log control. Two bullets are then fired through the center of the retaining pad which create a connection between the formation and a flow line to the sample chamber. When the chamber is filled, a valve is closed and the fluid sample sealed at maximum pressure. The tool is retracted to minimum diameter and brought out of the hole. Electrical circuits permit a complete recording at the surface of the mechanical operations of the tool as well as the formation pressure build-up and the hydrostatic mud pressure. The tool was introduced commercially during the latter part of 1955 in the Gulf Coasts of Louisiana and Texas. Over 1,000 operations have been made to date (Sept. 1, 1956); 50 per cent of which resulted in successful tests. Failures have been due mostly to ineffective sealing in unconsolidated sands. One major company had 41 successful tests out of 80 attempts with 23 ineffective pad seals. Results for this company were very gratifying as to pinpointing gas-oil ratios, indicating productive permeabilities and aiding in determination of fluid content where electrical log and side-wall coring information were inconclusive. Eight typical pressure curves are discussed (including misruns). Six types of fluid recoveries are interpreted. Eight actual field examples of electric logs, showing the problems solved by the formation tester, are illustrated. The present applications of the tool are discussed: 1. Determination of productive fluid—varticularlv differentiating between gas and oil. 2. Determination of reservoir pressure as an aid to: (a) safety in completion technique, (b) reduction in drilling costs, and (c) reservoir analysis. 3. Determination of minimum gas-oil ratios. 4. Location of gas-oil or oil-water contacts. 5. Recovery of samples for examination and analysis: oil (gravity); gas (hydrocarbon content); water (salinity). Additional applications envisioned for the future are also given: (I) subsurface exploration based on accurate pressure, (2) recovery of fluid samples from the undisturbed reservoir for PVT work, and (3) possible quantitative study of permeabilities or productivity index. Running the formation tester requires no special pre-cautionary measures. Because full hydrostatic mud pressure is maintained at all times, well depth is no problem. Thus, the method allows safe, economical testing in wells which heretofore could only be tested by setting casing. INTRODUCTION A new method of safely and rapidly testing possible producing formations in uncased holes is achieving considerable success. The method offers promise of further advances in reservoir study. Called the formation tester, the new instrument is unique in that it operates on logging cable. It thus offers all the advantages of wire-line operations and becomes an important adjunct to present logging and side-wall coring services. The tester is operated against the wall of the hole at any depth desired. Zones to be tested are usually determined by a study of the electrical and the micro-caliper surveys. Reservoir data, as well as the operating cycle of the tool in the hole, are continuously recorded at the surface during the operation. The tester, as it was originally designed, was capable of recovering a 1-gal sample of reservoir fluid per trip in the hole. Tools with reservoirs of 2.75- and 5.5-gal capacity are now available. The 5.5-gal reservoir is equipped with a segregating system, set before going in the hole, so that the last portion of the recovery (usually 1 gal) is automatically separated from the first portion. This makes it possible

Jan 1, 1958

By M. Cohen, D. Caplan

The scaling characteristics of three Fe-Cr alloys have been investigated by determining their weight gain vs. time curves at 1600° to 2000° F. The scales formed thereby have been examined using the techniques of X-ray diffraction and spectrographic and metal-lographic analyses in an attempt to explain the discontinuities in the curves and to elucidate the mechanism of scaling. DESPITE the considerable number of investigations that have been carried out on heat resistant alloys, the characteristics of the scales formed at high temperatures are not fully known. The research reported here was undertaken in an attempt to ascertain the mechanism of scaling of the stainless steels. Scaling experiments were carried out first, the weight increase of the specimens being followed continuously with time. It was observed that, as well as showing the expected decrease in oxidation rate with time, the oxidation curves showed breaks corresponding to intermediate periods of accelerated oxidation, after which protectiveness again increased. This phenomenon was observed with austenitic stainless steels (types 302, 309, and 330) and with Fe-Cr alloys (types 410, 430, and 446), but only the latter are treated in this report. An examination of the scales was made using the techniques of X-ray diffraction and spectrographic and metallographic analyses in an attempt to obtain a correlation between the nature of the scales and the oxidation curves. A search through the literature revealed only a very few previous reports of such periods of accelerated oxidation. Dunn' found breaks in the oxidation-time curves of some Cu-Si alloys but saw no rational explanation of the phenomenon. Heindlhofer and Larsen2 attributed a discontinuity in the weight gain-time curve of iron at 1290°F to the formation of blisters, the subsequent cracking of which exposed an unprotected surface and permitted rapid oxidation until a new protective scale had been reestablished. They advanced no explanation, however, for what they termed the peculiar behavior of a 27 pct Fe-Cr alloy at 2000°F which gained weight very rapidly in between two periods of very slow weight gain. Portevin, Pretet, and Jolivet3 in describing breaks in the weight gain-time curves of Fe-A1 alloys suggested that they might be associated with the occurrence of localized and deeply oxidized areas on the specimens. Bandel4 in a general discussion of oxidation curves of heat resistant alloys considered that the discontinuities were due to a local disruption of the protective layer by the growth of iron-rich oxides. Day and Smith" in their report on the scaling of a large number of iron alloys noted but did not explain occasional relatively rapid changes in oxidation rate at higher temperatures. Chevenard and Wache6 found breaks, often two per specimen, in the oxidation curves of an 18-8 type alloy. They suggested that the cause might be a depletion in chromium of the surface layer of metal due to its selective oxidation, the resultant high concentration of iron and nickel in the scale leading to a poorly protective scale. McCullough, Fontana, and Beck' explained the breaks in the oxidation curves of types 304, 430, and 410 alloys as due to mechanical ruptures. Experimental Work Table I lists the chemical compositions of the materials used. Cylindrical specimens 1/4 in. in diam and 11/2 in. long were machined from cold rolled % in. rod. After a fine finish cut with a sharp tool, the specimens were abraded while still mounted on the lathe with Nos. 2, 1, 0, and 00 metallographic grade emery papers. A 3/64 in. hole was drilled at a distance of 1/8 in. from one end to permit suspension in the furnace. Specimen Nos. 1, 2, and 3 were tested with this surface preparation. All others, after being similarly prepared, were electropolished in a perchloric-acetic electrolyte, electrical contact being made by pressing a tapered platinum hook into the drilled hole. The specimens were then washed in hot water, rinsed with distilled water, rinsed with methanol, dried at 120°F, and weighed. Thereafter,

Jan 1, 1953

By Herbert Banks Johnson

DURING the past 10 or 12 years very little information has been made generally available concerning the commercial possibilities of separating materials by means of static electricity; and yet during that same period important improvements have been made in various branches of the science of electricity, which, when taken together, and applied to electrostatic separation, have resulted in important improvements in that art as well. For example, much improvement has been made in high-voltage electrical equipment such as full-wave vacuum-tube rectification and improved mechanical rectification. Great strides have likewise been made in the development of insulators for high-voltage work, not only in the materials used but also in the design of the insulators themselves. Again, in another field, the development of air-conditioning equipment has improved the technique of controlling the surface condition, through drying or humidifying, of the various materials that are passed through the electrostatic separator. In many authoritative publications and textbooks, the electrostatic separation process is declared to require a balance far too sensitive for general commercial application. For example, one publication1 in the past has referred to an unfavorable effect on the process caused by varying atmospheric conditions such as humidity. Some2 have even gone so far as to state that sunlight and shadows may seriously affect the separating efficiency of the process. Such statements may have been true in the early development of the art, when the source of static electricity was derived from a friction disk machine, such as the Wimshurst. The Blake Mosher equipment and the work of Huff in applying motor- generator sets, transformers and mechanical rectification overcame much of this kind of objection to the commercial application of the electrostatic separating process. Another objection made periodically is that it is generally considered necessary to feed the particles into the electrostatic field in a stream that

Jan 1, 1938

By D. O. Hobson, P. L. Rittenhouse

We have recently found that many lots of Zircaloy-2 and -4 tubing tested in tension deform to cross section shapes that are "polyhedral" rather than circular. The noncircular cross sections seem to result from a circumferential variation in plastic proper -ties and, therefore, in texture. We examined the diffracted X-ray intensity from (OOOl), {1010), {ll20}, and {1011} planes parallel to the tubing surface around the entire circumference. Tubing that deformed to a circular cross section showed <5 pct variation in diffraction intensity around the circumference from any of these planes. Greater intensity variations were found for all the tubing materials that developed non-circular cross sections during deformation. In each instance the number of intensity maxima and minima was consistent with the number of sides of the &apos;polyhedral" cross section. THE effects of crystallographic texture on the mechanical properties of zirconium, zirconium alloys, and other anisotropic hexagonal materials such as titanium and hafnium have been intensively studied. If the natural crystallographic anisotropy of these materials could be controlled by selected fabrication operations, a material could be produced with a texture, or preferred orientation, in which the maximum strength directions are in the stress directions of the structure. The permissible stress levels of the structure could then be increased. Rittenhouse and Pickle-simerl have shown that highly textured Zircaloy-2 plate can vary from 52,000 to 70,000 psi in tensile yield and from 62,700 to 122,000 psi in compressive yield strengths as a function of specimen orientation. Similar texture effects have been observed in Zircaloy tubing, whose mechanical properties differ depending upon whether the tubing has basal poles predominantly radial or tangential and upon the mode of testing. These same texture effects might be troublesome if the texture in the tubing is not uniform around the tube walls. This paper is concerned with the effects of nonuniform texture on the strain behavior of commercial Zircaloy tubing. BACKGROUND Previously, various lots of commercial Zircaloy tubing were tested under selected stress conditions as part of a program to determine the four quadrants of the yield locus. One of the testing procedures was uniaxial tension and it is the influence of texture variations on the tensile deformation behavior of the tubing that is of interest here. The effect of texture on the strain behavior in tubing is very apparent from a uni-axial tensile test.2 This behavior is illustrated schematically in Fig. 1 for three different tubing textures: 1) basal poles predominantly in the radial direction; 2) basal poles predominantly in the tangential direction, and 3) basal poles equally distributed between the radial and tangential directions. In the first example most of the grains are oriented for prism slip to operate to allow axial lengthening and diametral reduction of the tube. Reduction in wall thickness requires {1122} twinning, a more difficult operation than slip.* In the second example, the texture is such that *The singleCrystal analogy will be used quite often in this paper when strong texturesare being discussed. The textured material is assumed to react as if it were a single crystal aligned in the same orientation and under the same stress system as the predominant texture._____________________________________________ prism slip operates to give axial lengthening and wall thinning. Diametral reduction requires twinning and again should be more difficult to accomplish. A specimen with basal poles equally distributed between the radial and tangential directions should exhibit about equal diametral and wall strains.* Table I shows the *Diametral strain is accomplished by a combination of circumferential and longitudinal strains. But, for the purposes of this paper, it will be considered as a strain causing a change in the length of a specified diameter.__________ strain behavior of two lots of tubing with different textures. The first tube has a texture with basal poles equally distributed between the radial and the tangential directions. The ratio of true thickness strain to true diametral strain is almost unity. The second tube has a predominantly radial basal pole texture and it is apparent that most of the total strain has occurred by diameter reduction, just as one would predict. There is over three times as much diametral strain as thickness strain. RESULTS We found that specimens from certain lots of commercially fabricated tubing did not retain round cross sections during uniaxial testing. Instead, the speci-

Jan 1, 1970

By H. R. Gardner

The heat treatmmt of plutonium was studied using the Jominy end-quenching technique commonly used for determining the hardenability of steel. Plutonium specimens were end-guenched from temperatures in each of the ß, y, d, d&apos;) and E phases. One series of specimens with a low-iron content, 165 pprn Fe, and another gvoup with a high-iron content, 678 pprn Fe, were used in order to study the effect of a Pu-Pu,Fe eutectic network on the hardness and micro-structure. Hardness traverses indicated no significant variations in hardness with either cooling rate or quench temperature. Metallographic studies indicated major effects on microstructure. Grain size was found to vary markedly with quenching temperature and cooling rate. It was determined that the Pu-PueFe eutectic network could be modified extensively by heat treatment, including spheroi -dization in the y phase and 6 phase below 413°C. An unidentified spheroidal inclusion was observed to go into solution in the delta and higher temperature phases. 1 HE element plutonium is unique among metals in that it has six allotropic forms in the solid state.&apos; These have been designated&apos; as the a, ß, y, d, d&apos;, and phases. The respective phase transformations occur at approximate temperatures of 122", 210°, 319°, 450°, and 480°C with a melting point at 640°C. With this number of phase transformations it becomes pertinent to consider the effect of heat treatment and cooling rate in the various phases on the microstructure and hardness of plutonium. To determine; the effect of a wide range of cooling rates, the Jominy end-quenching technique was applied to cylindrical plutonium specimens. In addition, since the presence of iron in amounts greater than 500 pprn is common in plutonium and results in a network of the Pu-Pu6Fe eutectic, it was decided to study heat treatment effects on two bomb reduced plutonium buttons with different iron contents. A low iron button containing 165 ppm Fe and a high iron button containing 678 ppm Fe were selected for this comparison. EXPERIMENTAL PROCEDURE Experimental Material. The cylindrical bars for Jominy quenching were cast from button stock in vacuo in MgO coated graphite molds. Metal pouring temperature was approximately 950°C and the molds were preheated to 300°C. The castings were machined to 0.5 in. diam. by 2.5 in. long cylinders. Chemical analysis and density data for the two groups of Jominy specimens containing different iron contents are presented in Table I. Except for iron, heats 19-12-1 and 20-2-1 are comparable within the limits of analytical accuracy. Representative specimens from the low-iron and high-iron bars were taken for metallographic examination. The low iron specimen was found to have extensive microcracking, Fig. 1. In addition, numerous unidentified spheroidal inclusions were present, Fig. 17. The average grain size of the low-iron plutonium is 0.068 mm, Fig. 4. In the high-iron plutonium, a Pu-Pu6Fe eutectic network is prominent, Fig. 7. The average size of the network is 0.100 mm. Unidentified spheroidal inclusions were also common in the high-iron plutonium. The average grain size of the high-iron plutonium is 0.036 mm. Experimental Technique. A Jominy end-quenching fixture was fabricated for glove box use. A 2.5 in. water height was used with an orifice of 0.250 in. ID. The orifice to specimen distance was maintained at 0.5 in. Annealing temperatures of 160°, 265°, 400°, 465°, and 535°c were chosen for the study of the effect of quenching from ß, y, d, d&apos;, and e phases on microstructure and hardness. During quenching, cooling curves were obtained from the Jominy specimens at distances from the quenched end of 1/16, 1/8, 3/8, 3/4, 1-1/4, and 2 in. Cooling rate calculations were made from the cooling curves for temperature intervals of 100° to 110° 160" to 170°, 330" to 340°, 420° to 430°, and 490° to 500°c. These temperature intervals were chosen

Jan 1, 1962

By D. M. Schuster, E. Scala

The elastic effects occurring in the matrix of a composite reinforced by discontinuous fibers were studied by means of photoelastic techniques. A hirefringent plastic was employed as the matrix material with high-strength a Al2O3 whiskers as the reinforcing fibers. It was found that for whiskers aligned parallel to the tensile load direction: (I) Matrix reinforcement occurred along the length of the whisker to within about 5 diameters of the whisker tip for a length to diameter ratio, L/D, of 40. (2) Significant stress concentrations were created in regions immediately surrounding the tips; the fine as-formed tapered ends exhibited the minimum stress concentration whereas the square-ended whisker produced relatively high values, K r 2.5 for L/D = 40. (3) The axial and radial stress distributions could he determined quantitatively; the stress distribution at the whisker-matrix interface was in general agreement with theoretical calculations. (4) The highest source of stress concentration occurred at points of fracture in whiskers which had ruptured after incorporation into the composite. Whiskers aligned perpendicular to the load direction neither reinforced nor caused appreciahle stress concentrations in the matrix. ThE properties of composites have generally been formulated empirically on the basis of macroscopic tests. There are still many questions concerning the mechanical and chemical interactions occurring at the interface between the reinforcing fiber and its matrix. Continuously reinforced plastics and dispersion-hardened metals represent the two extremes of composite reinforcement. Whether artificially produced or formed in situ, the whisker composite falls between these two extremes and is an example of discontinuous fiber reinforcement. The effect of fiber shape, size, surface condition, and end configuration on the stress distribution in the matrix is important since the presence of stress concentrations, especially in any high-strength, thin-wall structure, could become the cause of catastrophic failure. DOW,&apos; in his theoretical discussion of discontinuous fiber reinforcement, has pointed out that appreciable stress concentrations occur at the tips or ends of the reinforcing fibers. It is the purpose of this study to examine directly, by means of the photoelastic technique, the stresses which occur in the vicinity of a discontinuity or whisker tip and to measure qualitatively and quantitatively the effects of whisker geometry when embedded in a birefringent matrix material. The use of sapphire (a A1,O3) whiskers was decided upon as the reinforcing agent because of their high elastic modulus (E- 60 X 106 psi) and in some cases strengths in excess of one and a half million psi. Sapphire whiskers are of further practical interest since they retain large fractions of their strength up to temperatures approaching the melting point (3720oF).2 The whiskers were grown, by the vapor-phase reaction commonly employed,3 as part of this study to insure a physically uniform supply. Tensile and bend tests were performed to verify that the whiskers were of the expected ultra-high strength. The high-strength whiskers can be identified and selected from the combustion boats by surface perfection, shape, and size; otherwise, strength values can vary by a factor of ten or more. Macroscopic defects are quite common on the surface of large bladed whiskers and the principal experiments were conducted with hexagonal whiskers of about 0.002 in. diameter and lengths ranging from 0.1 to 0.4 in. Upon completion of these two phases of the experiment, several birefringent resins were evaluated. A plastic, developed by Zandman,4 which is supplied by the Budd Co., was found most suitable and was used as the matrix material for the whisker composite throughout the study. It has a sensitivity of 60.5 lb per in. order, calibrated in tension and cures without introducing residual stresses. Young&apos;s modulus for this matrix material is 430,000 psi in the fully cured condition. Since good wetting and bonding between the sapphire and the matrix material is essential to the interpretation of the results, a wettability test was performed. The contact angle was measured to be 168 deg where perfect wetting is defined as 180 deg; therefore, the Budd Plastic wets the sapphire

Jan 1, 1964

By R. W. Raymond

I HAVE the pleasure of exhibiting samples of the rock in which the South African diamonds are said to occur, for which I am in debted to Mr. Franz Groeger, of Vienna, formerly an assistant of the Royal Imperial Geological Institution, whose account of the general geology of Southern Africa was contained in a recent number of the proceedings of that Institution. The rock is apparently a sort of tufa, evidently of volcanic origin. Mr. Groeger assured me that it could be seen in situ, bounded by uplifted stratified rocks; and that diamonds had been mined from it, by means of shafts, some distance below the surface. Groeger calls it "greenstone-tufa," and says of it, in the proceedings of the Geological Institution, " it breaks through the younger members of Group III [lower Trias and Jura], . . .. and crops out in oval masses, filling fissures . . ..The occurrence of this tufa is not locally limited, but has been traced and proved already over a large territory." DR. HUNT remarked that the material looked like the trass of the Rhine region. He thought it a new occurrence for diamonds. He believed diamonds to belong to ancient crystalline rocks, although these materials might be brought tip by volcanic agency, and the diamonds remain unaltered. In the volcanic rocks of Auvergne, crystals of sapphire, zircon, and spinel are found; and yet no one supposes that these minerals have been generated by volcanic agency. He had had a conversation with Bertrand de Lom on this subject, who agreed with him that these minerals, being hard and resistant,

Jan 1, 1874

E. A. Loria (Product Metallurgical Engineer, Crucible Steel Co. of America, Pittsburgh)—In this interesting paper, our introductory work was quoted. We would like to call attention to our sequel paper on the experimental determination of oxygen in cupola-melted cast iron,20 which was not mentioned. Vacuum-fusion oxygen values (as well as hydrogen and nitrogen) were reported for nine heats of cast iron melted in the Battelle 10-in. cupola under normal operating practice and under oxidizing conditions. The oxygen analyses ranged from 12 to 68 pprn compared to the author&apos;s computed range of 10 to 80 ppm. The average amount of oxygen found in our irons was about 20 pprn and changes in the silicon content of the iron from 1.32 to 2.35 pct had no consistent effect on the oxygen content of the iron. The gas determination specimens were poured in split steel molds that produced a clean pin, 3/8 in. diam and 2 in. long. Because freezing was almost instantaneous, the pins were entirely white iron (nongraphitic). In the early stages of the investigation, the pins were transferred to a mercury-filled trap system immediately after pouring. This was done to collect gas evolved between pouring and analysis. However, it was found that during storage for 4 weeks gas evolution was negligible. Because the vacuum-fusion analysis was usually completed within 4 days of pouring, pins from later heats were not stored in the mercury-trap system. We found some evidence that cast iron picks up oxygen during long storage, because of rusting. Earlier work by the British Cast Iron Research Association has shown that cast irons may be stored for a long time without significant change in their oxygen content. The practical significance of this study (and our own) would be in the improvement of cast-iron quality. Has the author investigated this aspect and reached any conclusions on the effect of oxygen on the mechanical properties of cast iron? The second phase of our study was to determine the properties of the test bars poured simultaneously with the gas analysis specimens. We realize that there may be complicating factors attendant in this procedure.21 Results from many test specimens measuring chill depth, transverse flexure and deflection strength, spiral fluidity, and sensitivity to hardness of gray irons ranging from 12 to 68 pprn oxygen showed that the lowering of transverse strength was the only significant undesirable effect of high oxygen content. A statistical study of the chill test results21 showed that the iron containing 22 to 46 pprn oxygen had forced chill depths that were 2/32 in. below the expected value from their composition, and irons containing less than 16 ppm oxygen had forced chill depths averaging 1/32 in. greater than the expected chill depth. Higher oxygen contents, within the range of 12 to 68 pprn did not increase forced chill depth. With the wedge tests, there was a good linear relationship between carbon equivalent of the irons and their chill depth. The results indicated that oxygen contents below 50 ppm in the iron did not affect chill depth. With 50 to 70 ppm oxygen in the iron, oxygen appeared to have a slight graphitizing tendency. These results are in disagreement with the common belief in gray iron foundries that "oxidized irons" produce high chill depths. It would be appreciated if the author would comment on this subject. Gustaf Ostberg (author&apos;s reply)—In Fig. 1 the legend of line I should read 2 pct C, 1 pct Si. The author wishes to thank Mr. Loria for calling attention to his later work, which was published after the present paper was concluded. The range of oxygen contents quoted seems to agree well with the author&apos;s values. The lack of response to variations in silicon content is probably due to the fact that the oxygen content in most cases was below the saturation level. The absence of temperature dependence, even in the case of saturation, is understandable if the difficulty in formation and escape of the deoxidation products is taken into account.

Jan 1, 1960

By C. D. Ramsden

DURING the war years of 1941 to 1945, maintenance of mine locomotives and other mine equipment took the form of rebuilding rather than of renewing. Pur¬chase of new parts became increasingly difficult and mine operators found it necessary to maintain equipment by sal¬vaging old parts. Mine-locomotive wheels, although not representing a high cost per pound of material, contain a con¬siderable amount of steel and without rebuilding would have to be scrapped long before even a moderate percentage of the steel in the wheel is actually consumed. Many mine operators have been re¬building locomotive wheels for several years with automatic open arc-welding equipment. In 1927, the Pittsburgh Coal Co. started such a program, using a single Westinghouse automatic welding head. Since that time, many refinements have been added, until in 1944 the setup was operating very efficiently. A desire to increase wheel life and to hold down rising costs led the company in 1944 to investigate the possibilities of the under¬flux arc-welding process for wheel rebuild¬ing, although at that time, little or no work had been done on multiple pass or "build-up" welding with the underflux arc. Work with this process had been confined largely to welding together flat plates in a "down hand" position. Possibilities for savings were intensified by the fact that the company has 300 locomotives in operation, using actively or as spares 1200 sets of wheels. During 1942 and 1943, about 500 sets of wheels were sent each year to the company&apos;s maintenance shop at Library, Pa., for rebuilding. Based on having 800 sets in service (many of the company&apos;s heavy locomotives have three- sets of trucks), the average life of a set of wheels was approximately 19 months. Anything that could be done to increase wheel life promised sizable annual savings. OPEN ARC WELDING With the open arc process, a set of wheels could be rebuilt for about 40 pct of the cost of new wheels. Underflux arc welding gave promise of greatly increased welding speeds, more homogeneous, dense deposits and the chance for use of a wider range in welding-wire compositions. Against this was ranged the higher cost of materials and the cost of developing the process from the theory to a practical reality. Since 1927, when a single open arc head was placed in operation, fixed welding procedures had been gradually developed, a positioner for handling a set of wheels was built, and a second head was placed in operation in order to weld two wheels simultaneously. The fixture, or posi¬tioner, which was built to position and turn the wheels under the two welding heads, included a motor drive, controlled by a rheostat, which rotated the wheels through a double set of speed reducers and a removable jaw coupling attached to one end of the axle of the wheel truck.

Jan 1, 1946

By P. S. Kotva

Dislocation substructures in superalloy matrices of varyzng co)npositions have been studied. In general, it has been found that the alloys can be classified into &apos;&apos;high", &apos;&apos;medium", and "low" stacking fault energy classes based on the type of dislocation substructure observed in the matrix and that the substructure can be correlated to the stacking fault energy. The effect of different types of dislocation substructure and dislocation reactions on the intragranulur precipitation of carbide phases has been studied. In a Ni-Cv-Mo-Fe matrix, precipitation of MC carbides in association with stacking faults has been observed. In most superalloys, solid-solution strengthening and precipitation hardening are the chief mechanisms employed to achieve strength. The latter contribution to strength is usually achieved by the precipitation of / in certain wrought alloys. Insufficient attention has been given to the problem of obtaining strength in su-peralloys by controlling precipitation of carbides on imperfections within the matrix. The present work was undertaken to investigate the dislocation substructure in various superalloy matrices, to study the effect of such substructure on subsequent precipitation of carbides in the matrix, and to investigate whether certain modes of precipitation of carbide phases found in austenitic stainless steels2"4&apos;6 would occur in nickel-base alloy matrices with dislocation substructures of the same type as those found in austenitic steels. 1) EXPERIMENTAL TECHNIQUES Five-pound heats of the various alloy compositions reported here were vacuum-cast. The ingots were given light deformation by rolling to break up the as-cast structure and then homogenized for 24 hr. HASTELLOY alloy X (nominal composition: Ni-2OCr-17Fe-8Mo-0.05C) was homogenized at 2150°F and In-cone1 625 (nominal composition: Ni-20Cr-5Fe-8Mo-3.5Cb-0.05C) was homogenized at 2280°F. Fabrication of 0.004-in. sheet was achieved by cold rolling with intermediate annealing treatments being carried out at the same temperature as those used for homogeniza-tion. Each solution anneal was followed by quenching. The aim of this procedure was to redissolve as much of the primary carbide phase as possible. Samples of the 0.004-in. sheet were cut and encapsulated in quartz capsules and then heat-treated in the tube furnaces. Thin foils were prepared using an ethanol-10 pct perchloric acid bath at 32°F and at a voltage of 22 v. A "window" technique was employed. Observations were made on a JEM-7 electron microscope operating at 100 kv. 2) EXPERIMENTAL RESULTS a) Types of Dislocation Substructure. Fig. 1 shows a schematic correlation between stacking fault energy, SFE, and the type of dislocation substructure observed in various matrices of nickel- and cobalt-base alloys. A precise quantitative determination of stacking fault energy is not implied in the figure but the correlation between stacking fault energy and the type of dislocation substructure obtained allows alloys to be divided into three classes in analogy with the classification employed by Swann and ~uttin~&apos; for binary alloys of copper. Class I alloys are associated with a "high" SFE and show a cellular substructure of dislocations as typified by the micrograph of a thin foil of pure nickel deformed 4 pct at room temperature in Fig. 2. With decreasing SFE the tendency toward cell formation is lessened and dislocations tend to be arranged in coplanar groupings. Examples of this class of alloys with "medium" SFE are provided by the mi-crostructure of solution-heat-treated, quenched, and deformed thin foils of HASTELLOY alloy X, "Waspaloy" (prior to any aging), and Inconel 625. Fig. 3 shows a thin-foil micrograph of an alloy of Inconel 625 composition, solution-heat-treated, quenched, and deformed 5 pct at room temperatures. No evidence of any cell structure can be obtained in materials of "medium" stacking fault energy, Fig. 3, even after severe deformation. The stacking fault energy of the alloy shown in Fig. 3 is, however, not low enough to make the dissociation of dislocations visually obvious. As stacking fault energy decreases further, with successive addition of solute in the matrix, there is an increased tendency toward dissociation of dislocations and cross slip becomes progressively more difficult. Eventually, when the stacking fault energy is "low" enough, complete dissociation of dislocations is seen to occur as shown in Figs.

Jan 1, 1969

Jan 1, 1968

By Roshan B. Bhappu, Ronald J. Roman, Dexter H. Reynolds

The reaction between manganese dioxide and molybdenite in a water- sulfuric acid medium was studied at atmospheric pressure and from 25° to 103°C. Both solids are dissolved to give, as final products in solution, Mo(VI), S(VI), and Mn(II). Stoichiornetric relationshifis are most simply represented by the equation MoSz + YMnO2 + 15H+ - HMoO-4 + 2HSO-4 + 9Mn++ + 6H20 The rate of this reaction was found to be dependent on temperature, manganese sulfate concentration, acid concentration, and, in a complex way, the surface areas of both manganese dioxide and molybdenite. Both the total amount of manganese dioxide and tnolybdenite and the ratio of manganese dioxide to molybdenite played a part in determining the over-all rate of the reaction. The effect of acid concentration on the rate was also dependent on the ratio of manganese dioxide to molybdenite. SEVERAL reports in the literature describe reactions using manganese dioxide in water-sulfuric acid media as an oxidizing agent. Nearly all previous work describes interactions between an ion and manganese dioxide, such as the oxidation of ferrous to ferric iron,&apos; or the interaction between a molecule in solution and manganese dioxide, such as the oxidation of toluene to benzaldehyde.2 Only a few references describe the use of solid manganese dioxide to oxidize another solid in sulfuric acid. One report3 states, "Manganese dioxide in dilute sulfuric acid solutions had no beneficial effect (in leaching copper from chalcopyrite), but in more concentrated acid solutions the rate of solution was about the same as that for permanganate." In 1902 a German patent4 described a process which used manganese dioxide in strong (50°Be&apos;) sulfuric acid for oxidizing chromite ores to soluble iron and chromium salts. The process consisted of mixing the sulfuric acid with the finely ground ore and manganese dioxide. The pulp was then heated to about 120°C and an electric current passed through it. The manganese dioxide apparently dissolved in the strong, hot acid solution, oxidized the iron and chromium and itself was reduced to manganese 11! then was oxidized at the anode back to manganese dioxide, and the cycle repeated. An extensive study5 of the kinetics of the oxidation of pyrite with manganese dioxide indicated that in dilute sulfuric acid solutions (about 0.1 N) and at elevated pressures the dissolution of the pyrite was brought about by air oxidation of the iron to ferrous sulfate, followed by manganese dioxide oxidation of the ferrous sulfate to ferric sulfate. The mechanism proposed by the authors involved the oxidation of the iron at the surface of the manganese dioxide. Also! the oxidation of sulfide sulfur to sulfate was credited to the oxygen in the air, not to the manganese dioxide. Since the metallurgical literature is lacking in information concerning the use of one solid to oxidize another solid. the current investigation was under-

Jan 1, 1965

By Reginald Williams

THE amount or value of the precious metals consumed in dentistry is probably amazing to most people. It falls very little short of that which is consumed in jewelry. Inasmuch as the ultimate destination is in the human mouth, dental alloys enjoy some importance because life and health depend upon restorations made with them. Prosthetic dentistry has made wonderful progress in the last few years. The manufacturers who supply the metals also deserve commendation. This industry which deals with metals to go into people&apos;s mouths is comparatively new. There is no literature on the subject, and little or no precedent by which to be guided. It was only by close cooperation with the dentist or prosthetic technician that desirable physical properties were produced, as nearly as possible, in the metals which were available and permissible. It is true that there were and still are conflicting opinions among the dentists as to the physical properties they require. Sometimes they request the impossible, such as alloys which are exceedingly stiff and springy, yet will bend or adjust easily. Even in this latter instance, progress has been made by supplying methods of heat-treatment whereby metals may be softened or hardened at will. (Figs. 1 and 2.) The demands made upon manufacturers are extremely varied. They must supply metals of tensile strengths ranging from approximately 30,000 to 100,000 lb. per sq. in. and over. The latter metals must be workable and in many instances capable of extreme deformation. They must not be affected by mouth conditions, nor should they oxidize greatly when molten, at red heat, or during a soldering operation. In addition to physical specifications, color demands must also be met. The firm of which I have the most knowledge manufacturers 11,553 standard stock articles of precious metals, taking into consideration formulas, finenesses, grades, colors, gages, lengths, sizes and weights. If special demands are taken into consideration, the number would be in excess of 25,000. Wrought metals are manufactured in a great many alloys of different sizes and shapes, such as plate, bar, rod, wire, sheet, strip, mesh and foil. There are also other products of importance.

Jan 1, 1928

By R. E. McNulty, R. D. Heidenreich, C. H. Gerould

TIIE electron microscope techniques and their application to magnesium alloys that are to be discussed in this paper are the result of research at The Dow Chemical Co. over the past three years. The view- point underlying the work is not wholly metallurgical, but has evolved through a variety of problems related to the physics and chemistry of surfaces. It can be said that the interest and stimulus were closely associated with a desire to employ effectively the electron microscope in research concerning the properties of solids as related to their physical structure. Only a portion of this work will be described here, and, consequently, many points of interest and debate are of necessity either only briefly recognized or are completely omitted. As has been pointed out by Desch,1 a great deal of the knowledge of the structure of metals has been obtained through microscopic studies of the surfaces of metallic specimens prepared in a particular manner. This information, when added to that obtained by means of thermal, electrical, X-ray, dilatometric and other methods, has been of great value both from a theoretical and a practical view- point. With the introduction of new instruments such as the electron diffraction camera and the electron microscope, it would be expected that still more information could be obtained. These two instruments have in many instances been very effective when directed toward the investigation of metallic surfaces, provided the proper methods of surface preparation were employed. Experience shows that the problems of surface preparation greatly limit the general application of these instruments to metallographic studies. It was found necessary to discard the standard metallographic procedures in applying the electron microscope to magnesium alloys and to work out new methods, which were required to satisfy certain conditions. These methods are unique to magnesium only in the specific chemical reactions occurring during etching. The presentation of the methods and results will be ordered as follows: I. Electron Microscopy of Surfaces. 2. Surface Preparation of Magnesium Alloys. 3. Discussion of Microstructures. a. Pure Magnesium and Single-crystal Studies. b. Types of Precipitation. c. Some Common Structures. d. Special Micrographs and Techniques. e. Structure of Mg-A1 Solid Solutions. 4. Correlation of "Fine Structure" with Corrosion Behavior of Magnesium Alloys.

Jan 1, 1946

By Reginald Williams

THE amount or value of the precious metals consumed in dentistry is probably amazing to most people. It falls very little short of that which is consumed in jewelry. Inasmuch as the ultimate destination is in the human mouth, dental alloys enjoy some importance because life and health depend upon restorations made with them. Prosthetic dentistry has made wonderful progress in the last few years. The manufacturers who supply the metals also deserve commendation. This industry which deals with metals to go-into people&apos;s mouths is comparatively new. There is no literature on the subject, and little or no precedent by which to be guided. It was only by close cooperation with the dentist or prosthetic technician that desirable physical properties were produced, as-nearly as possible, in the metals which were available and permissible. It is true that there were and still are conflicting opinions among the dentists as to the physical properties they require. Sometimes they request the impossible, such as alloys which are exceedingly stiff and springy, yet will bend or adjust easily. Even in this latter instance, progress has been made by supplying methods of heat-treatment whereby metals may be softened or hardened at will. (Figs. 1 and 2.) The demands made upon manufacturers are extremely varied. They must supply metals of tensile strengths ranging from approximately 30,000 to 100,000 lb. per sq. in. and over. The latter metals must be workable and in many instances capable of extreme deformation. They must not be affected by mouth conditions, nor should they oxidize greatly when molten, at red heat, or during a soldering operation. In addition to physical, specifications, color demands must also be met. The firm of which I have the most, knowledge manufacturers 11,553 standard stock articles of precious metals, taking into consideration formulas, finenesses, grades, colors, gages, lengths, sizes and weights. If special demands are taken into consideration, the number would be in excess of 25,000. Wrought metals are manufactured in a great many alloys of different sizes and shapes, such as plate, bar, rod, wire, sheet, strip, mesh and foil. There are also other products of importance.

Jan 1, 1928

By R. W. Raymond

I have the pleasure of exhibiting samples of the rock in which the South African diamonds are said to occur, for which I am indebted to Mr. Franz Groeger, of Vienna, formerly an assistant of the Royal Imperial Geological Institution, whose account of the general geology of Southern Africa was contained in a recent number of the proceedings of that Institution. The rock is apparently a sort. of tufa, evidently of volcanic origin. Mr. Groeger assured me that it could be seen in situ, bounded by uplifted stratified rocks; and that diamonds had been mined from it, by means of shafts, some distance below the surface. Groeger calls it " greenstone-tufa," and says of it, in the proceedings of the Geological Institution, " it breaks through the younger members of Group III [lower Trias and Jura], .... and crops out in oval masses, filling fissures.....The occurrence of this tufa is not locally limited, but has been traced and proved already over a large territory." Dr. Hunt remarked that the material looked like the trass of the Rhine region. He thought it a new occurrence for diamonds. He believed diamonds to belong to ancient crystalline rocks, although these materials might be brought up by volcanic agency, and the diamonds remain unaltered. In the volcanic rooks of Auvergne, crystals of sapphire, zircon, and spinel are found; and yet no one supposes that these minerals have been generated by volcanic agency. He had had a conversation with Bertrand de Lorn on this subject, who agreed with him that these minerals, being hard and resistant,

By Frederic P. Dewey

By the old method of determining platinum in ores and bullion, the silver-alloy first obtained in the regular course of assay is parted in strong sulphuric acid and the residual metal weighed. This is re-alloyed with silver by a second cupellation and parted in nitric acid, the residual metal being again weighed. Any difference shown between the two weighings is assumed to be, and is called, platinum. Sometimes it is SO, and if any considerable amount of platinum be present, there will be a decided difference between the two weighings; but a slight difference is no real evidence whatever of the presence of platinum. On the other hand, the second weight may equal or possibly exceed the first, even when traces of platinum are present. Again, other members of the platinum group may go into solution in nitric acid more or less. If present, these would be called platinum and escape detection. The method does not provide any direct tests whatever as to the presence or absence of platinum. It is often indecisive, and sometimes gives erroneous results. It is, therefore, quite unsatisfactory. Being called upon many times to determine platinum in a wide variety of materials, particularly when present in very small amounts, I have realized the disadvantages and defects of this old method. In an article on the solubility of gold in nitric acid,&apos; I have briefly outlined a method of gathering a little gold out of a solution containing much silver, which furnishes the basis of

Jan 1, 1913

By C. W. Mueller, P. H. Robinson

A technique was developed for depositing single -crystal films of silicon on single-crystal sapphire substrates via the pyrolytic decomposition of SiH4/H2 mixtures. Electron diffraction and X-ray Laue reflection examinations of these films revealed single-crystal patterns. These films were characterized by measuring conductivity type, thickness, resistivity, and Hall mobility. Chemical etching, dislocation staining, and electron-microscopy examination have indicated the presence of low-angle grain boundaries and microtwinning in the silicon films. The role of the sapphire substrate with respect to its quality, orientation, surface finish, and thermal and chemical treatment was investigated. Hall mobility as a function of sapphire orientation was measured. A mobility equal to 88 pct of bulk silicon mobility was attained. Insulated-gate field-effect transistors which have a transconductance of 4000 pmho at 6 ma were fabricated using these films. THE technology of the fabrication of microelectronic circuits with active and passive components directly on a single wafer of semiconductor material has attained a high degree of perfection during the last few years. One inherent difficulty with the single-wafer approach has been undesirable coupling between components arising from the common base material. Several techniques have been developed for minimizing this coupling and obtaining good electrical isolation between components; however, these result in extra capacitance being added to the circuit. The extraneous capacitance of the connecting leads, resistors, and capacitors degrade circuit performance and limit the high-frequency operation of these circuits. Recently there has been considerable interestl-3 in the deposition of silicon films upon insulating substrates. The use of silicon as the semiconductor allows the subsequent utilization of the large amount of technology which has been developed for silicon for the fabrication of good active components. A sapphire substrate supplies an excellent insulating material which at the same time gives a thermal-conductivity improvement of an order of magnitude over glass-type substrates. This paper will describe the results obtained for the deposition of single-crystal silicon layers upon single-crystal sapphire substrates as well as the characterization of these films. I) APPARATUS The &apos;system used for the growth of silicon films on sapphire substrates by means of the pyrolysis of SiH4/H2 mixtures is shown in Fig. 1. The all-quartz reaction chamber is water-cooled and includes a quartz optical-flat window for use in conjunction with a 5 kw, 2.5 Mc per sec constant-temperature controlled rf generator. The temperature sensor for the rf generator is a thermopile which is focused through the quartz optical flat onto the susceptor surface. With this system the rf generator will hold the temperature of the susceptor to about +0.3°C at 1200°C. The susceptor is supported on a quartz sled inclined to the gas flow to increase the uniformity of the deposition. The water jacket surrounding the reaction chamber is used to keep the quartz wall temperature low enough to limit the decomposition of the silane to the rf-heated susceptor which contains the sapphire substrates. This eliminates the reaction of silicon with the hot quartz to form SiO which deposits out on the apparatus walls, thus obscuring vision, and interferes with the optical measurements of the temperature as well as with the growth process itself. Provision is also made for "n"- and &apos;p"-type doping by using mixtures of either phosphine or diborane in hydrogen which are added to the silane during the growth process. The hydrogen used is the purest commercially available tank hydrogen further purified by use of a palladium diffuser. The susceptors which were used include 1) spectro-scopically pure graphite, 2) high-purity molybdenum, 3) high-resistivity silicon using a low-resistivity insert to facilitate coupling to the rf generator, 4) silicon carbide-coated graphite. The latter two susceptor materials produced silicon films on sapphire substrates with more reproducible resistivities. Prior to silicon deposition all connecting lines as well as the reaction chamber are thoroughly flushed with argon and then hydrogen. After the hydrogen flow is set, the growth temperature is adjusted to 11009 to 1150°C, and when thermal equilibrium is reached the silane flow is started. The flow rate of the hydrogen must be fast enough so that turbulent flow occurs in the size of reaction tube used, otherwise a streaked nonuniform silicon deposit occurs. After the deposition

Jan 1, 1967

By U. C. Tainton

The paper reviews the evolution of electrolytic zinc, describing some of the major obstacles that have been encountered and overcome. The chief remaining limitations of present-day standard practice are: Difficulty of obtaining high extractions, especially from low-grade and complex ores; filtration troubles, if ores contain much soluble silica; and irregularities in electrolysis, if more than certain limited amounts of antimony, arsenic, cobalt; etc., are present in the ores. These factors dictate a relatively high-grade plant feed, thus subjecting the electroytic-zinc process to the same kind of limitations as the zinc smelter. The "high acid process," in which both acid strength and current density are raised to about four times the usual figures, is described. This system concentrates both plant and operations, allows a simple type of flow sheet, and. minimizes some of the difficulties above mentioned. The large-scale operation of the process is described. SOME time ago, at a meeting of the Institute Prof. J. W. Richards1 said, "I take exception to the statement that all the factors in the production of electrolytic zinc were known long ago. There is possible in my opinion an improvement of perhaps 50 per cent. in the new electrolytic processes." An examination of the literature of the subject will show the justness of Professor Richards&apos; contention. The work of the earlier investigators was carried on in the shadow of difficulties that, today, are hardly more than memories. We seldom hear now of zinc sponge, that bête noir of the electrolytic-zinc pioneers. Zinc sponge, was the name given to a peculiar, soft, black, non-adherent form of zinc deposit that was utterly useless for melting into ingot form. At the big plant at Cockle Creek, New South Wales, in 1897, Edgar Ashcroft2 said that the solution in the plant would suddenly, and without ascertainable cause, go "bad" and begin to deposit spongy zinc. The most delicate, even spectroscopic, methods of analysis were unable to detect any difference between "good solution and "bad" solution; either form might change to the other on being kept for a while. When it is added that an outbreak of this insidious disease (which. appeared to

Jan 2, 1924

By H. E. Searle, Robert J. McKay, O. B. J. Fraser

The practical study of corrosion requires consideration of its economic aspects. It must be based on sound scientific principles, but it should be borne in mind that probably the most important object of a corrosion test is to determine what metal in corrosion-resisting construction will produce the greatest operating profit. Thus the corrosion test must be directly connected with money values or it is not a practical corrosion test. This, perhaps unusual, connection between corrosion and economics is partially due to the fact that corrosion deals only with the time factor or duration of equipment, and it is almost the only test which deals with this feature. In these statements a departure is made from the academic definition of the word corrosion and it is done deliberately. The use of the term corrosion is unusual. It is as though we spoke of a tensile test as a "breaking" test. We are not interested primarily in the break but in the strength of the metal. There is no English word which expresses our main interest in corrosion-testing, but let us have clearly in mind that we make corrosion tests to prevent corrosion. Our real interest is in this corrosion-prevention, not in the corrosion. Previous to 1922, it was common comment that "it is impossible to determine the course of corrosion by laboratory testing.&apos;&apos; This statement was true at that time in that the technique of laboratory testing for corrosion resistance was so vague that tests in the laboratory gave untrue results almost as often as true ones. This was so, even in the simple case of determining which one of two metals better resists a given solution. While this is no longer true the number of misleading "corrosion tests" still being ground out by laboratories is too large in the light of our present knowledge. There are two important features of corrosion testing whose neglect is a large contributing factor to misleading results: (1) The economic relations of the corrosion tests to other tests; (2) testing technique. Regarding economic relations J. F. Thompson l has said: "The use of any particular metal is rarely based upon the sole property of resistance to corrosion. In fact, I should like to venture the assertion

Jan 1, 1929