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By R. W. Moore, A. B. Kinzel

Although the iron-carbon diagram has undergone many changes in the last 20 years, the region below the eutectoid line and up to approximately 1.7 per cent carbon has been little affected. This region is generally considered to consist of cenlentite and ferrite. Graphite has been noted occasionally in the hypereutectoid steel region, and the ready formation of graphite nodules in malleable cast iron is a phenomenon difficult to interpret in the light of cementite, supposedly stable at sub-eutectoid temperatures. In this case the graphite formation has been partly explained by the presence of silicon, and many have believed that silicon acts to change the stable state rather than to accelerate reactions so as to arrive at the stable state in a briefer period of time. Consideration of this phenomenon indicates that cementite is not the stable phase in the temperature composition zone referred to. In the course of examining a low-carbon steel tube taken from a petroleum cracking still, which had been in service for approximately three years at temperatures somewhat below the eutectoid temperature, observations were made that shed light on this entire subject. The tube in question analyzed:' C, 0.15 per cent; Mn, 0.49; Si, 0.02; S, 0.023; P, 0.015. The microstructure of the tube after service is shown In Figs. 1 and 2. From these it is evident that cementite as such is absent, and that in its place nodular graphite has been formed. In order to check this observation further, samples taken from the tube were heated at 850" C. for varying periods of time. The small samples were put into a large hot furnace, and the total time is recorded. The structure of the sample after 5 min. at 850" C. is shown in Figs. 3 and 4, and the nest of pearlite surrounding the graphite nodules is most satisfactory evidence of the character of the nodules. As the length of time of heating at this temperature increases, the pearlitic zone increases, with final restoration

Jan 1, 1935

By R. W. Moore, A. B. Kinzel

Although the iron-carbon diagram has undergone many changes in the last 20 years, the region below the eutectoid line and up to approximately 1.7 per cent carbon has been little affected. This region is generally considered to consist of cenlentite and ferrite. Graphite has been noted occasionally in the hypereutectoid steel region, and the ready formation of graphite nodules in malleable cast iron is a phenomenon difficult to interpret in the light of cementite, supposedly stable at sub-eutectoid temperatures. In this case the graphite formation has been partly explained by the presence of silicon, and many have believed that silicon acts to change the stable state rather than to accelerate reactions so as to arrive at the stable state in a briefer period of time. Consideration of this phenomenon indicates that cementite is not the stable phase in the temperature composition zone referred to. In the course of examining a low-carbon steel tube taken from a petroleum cracking still, which had been in service for approximately three years at temperatures somewhat below the eutectoid temperature, observations were made that shed light on this entire subject. The tube in question analyzed:' C, 0.15 per cent; Mn, 0.49; Si, 0.02; S, 0.023; P, 0.015. The microstructure of the tube after service is shown In Figs. 1 and 2. From these it is evident that cementite as such is absent, and that in its place nodular graphite has been formed. In order to check this observation further, samples taken from the tube were heated at 850" C. for varying periods of time. The small samples were put into a large hot furnace, and the total time is recorded. The structure of the sample after 5 min. at 850" C. is shown in Figs. 3 and 4, and the nest of pearlite surrounding the graphite nodules is most satisfactory evidence of the character of the nodules. As the length of time of heating at this temperature increases, the pearlitic zone increases, with final restoration

Jan 1, 1935

In Bulletin J 1, recently published by the Traylor Engineering and Manufacturing Co., it is stated that the largest jaw crusher ever built has a jaw opening of 66 in. by 86 in. and weighs 680,000 1b. It is said to be in successful operation and has a capacity of 490 tons per hour crushed to 12-in. size; 415 tons per hour crushed to 10-in. size; 330 tons per hour crushed to 8-in. size. The same company, in its Bulletin G 3, gives a diagram showing the percentage of a crushed product which will pass through screens of different sizes of perforation from a machine adjusted to a certain size screen. This diagram is reprinted below for the information of our members and the following notes apply to it. In order to prevent an excessive amount of fines, crushing machines are usually set so that 15 per cent. of the product will be larger than the maximum size desired, and this oversize is then recrushed by smaller

Jan 10, 1916

[NUMERICAL CODE TO MAPS (Region Listed in Roman Numerals after Each Petroleum Section) 1 Alaska 2 Arizona 3 Black Hills 4 Boston 5 Carlsbad Potash 6 Central Appalachia 7 Chicago 8 Cleveland 9 Colorado 10 Columbia 11 Connecticut 12 Delta (VIII) 13 Detroit 14 East Texas (VI) 15 El Paso 16 Gulf Coast (VII) 17 Kansas (IX) 18 Lehigh Volley 19 Mid-Continent (IX) 20 Minnesota 21 Montana 22 Nevada 23 New York]

Jan 1, 1961

By James Douglas

An address before the Meeting of the New York Section, Nov. 4, 1914. As life advances one is inclined to look backward instead of forward, and the vista over which my memory carries me has been filled with such a shifting panorama of changes in metallurgy that the whole practice of the art seems to have been re-created. The first cupola furnace that I saw in operation was at one of the group of mines at Capelton, Quebec, from which the Nichols company still draws some of its sulphur supply. At that time it was operated by a Hartford, Conn., company, under a General Adams. When its small brick furnaces made a campaign of a week and smelted 10 tons a day, the feat redounded to the credit of the operator. The introduction of the water-jacketed cupola dates forward to the next decade. I was using one in Pennsylvania, making copper matte, to the horror of a noted metallurgist, who could not conceive it possible that you. could bring fused sulphides in contact with steel without rapid corrosion. In our ignorance we were doing what seemed to be an impossibility, and it is just that recklessness and disregard for precedent which has characterized so much of the work of American metallurgists, and carried us forward at such headlong speed. Once the water jacket was accepted as the type of the. copper cupola, its almost unlimited expansion in length, but not in width, was a matter of convenience rather than of skill. In Butte the cupolas have been enlarged by adding furnace to furnace. The first reverberatories which I saw in operation were those in Professor Hill's Black Hawk establishment, where the concentrates from the Gilpin County gold mills were run down into matte for separation in England. Sixty dollars per ton was the usual deduction in those days before gold and silver was paid for. Smelting was done with wood as fuel, and the capacity of the furnace was about 10 tons per diem. Shortly after this Professor Hill formed an alliance with Richard Pearce, who was running what, if I recollect aright, was called the Swansea Works, at the bend of the river approaching Georgetown.

Jan 4, 1915

By L. A. Rapoport, W. J. Leas

The original Burkley-Leverett theory has been extended and a more detailed formulation of the waterflood behavior in linear horizontal systems is presented. Particular consideration has been given to the evaluation of capillary pressure effects and differential equations permitting an explicit evaluation of these effects have been derived. On the basis of the developed theory it is recognized that the flooding behavior is dependent upon the length of the system and the rate of injection. At the same time it has been determined that systems of different lengths yield the same flooding behavior if the injection rates and or the fluid viscosities are properly adjrrsted or "scaled." It has also been found that the sensitivity of the flooding behavior with respect to rate and length decreases as any one of these {actors increases in value and that for sufficiently long systems and high rate.; of water injection the flooding behavior becomes independent of rate and length. or "stabilized." To such stabilized conditions the theory formulated by Buckley and Leverett is applicable. A number of laboratory flooding tests have been made and good agreement Iraq been found between theory and experimental observations. The experimental results are discussed and it is shown that under field conditions the flooding behavior is usually stabilized. As a result of these finding; a procedure is indicated for evaluating field performances either on the basis of tests performed with commonly available core samples or by means of calculations using relative permeability data INTRODUCTION In recent years the development of methods for evaluating oil recovery by waterflooding has been the object of considerable research. A theoretical analysis of the mechanisms involved in the displacement of immiscible fluids was originally established by Buckle!- and Leverettl and experimental investipatio~~s have been made by numerons workers." Many of the experimental results are in mutual agreement and bear out several significant features of the flooding mechanism as predicted by theory. Thus it lias been generally recognized that a flood corresponds to the movement of a steep saturation hank or "front" (primary phase), followed by additional gradual oil displacement (subordinate phase). It has also been found that for any porous medium the flooding behavior is largely dependent upon the oil-water viscosity ratio and that for increasing values of this ratio the relative importance of the primary displacement phase decreases while that of the subordinate phase becomes more pronounced. Although the studies to date have clarified certain aspects of the flooding process. they have given rise to observations of a somewhat contradictory nature that cannot he explained in terms of the original theory. These observations pertain mainly to the effect of injection rate or pressure gradient upon recovery. Some investigators report laboratory tests that indicate incresing oil recoverieq with increasing rates of water injectill, others find the flooding behavior to be independent of and other. mention lower oil recoveries with increased injection rates.3 The conflicting evidence indicated above creates considerable uncertainty with respect to laboratory testing procedures and the utilization of the resulting data for field evaluations. The principal purpose of this paper, then, is to resolve these Uncertainties by means of a comprehensive theoretical and experimental investigation of the flooding meanism. THEORETICAL DEVELOPMENT Derivation of Flooding Equations The mathematical description of transient flow phenomena is based upon the consideration of the various processes occurring during an infinitesimal time interval in an infinitesimal volume element and upon the correlation of these processes with those occurring in the adjacent elements. The volume elements are defined as being infinitesimal in comparison to the overall dimensions of the porous system, yet each sufficiently large so aS to encompass the full range of pore openings encountered throughout the system. If a porous system can arbitrarily be subdivided into an infinite number of volume elements all possessing the same distribution of pore openings and if this distribution is unformly continuous. the system may be said to be homogeneous. Such a homogeneous porous medium is considered in the present studivs. It is furthermore postulatecl that only oil and water are present in the pornu wediu. that they act a- totally incompressible and immiscible fluids. and that gravity effects are negligible. In n linear flow system of unit cross sertional area. as treated here. the infinitesimal volume element.; to he considered are cylindrical ".slices" of thickness dx. oriented perpendicularly to the direction of flow. The equations applicable to any such volume element. at my time. describe the movement. of oil and water across the element:

Jan 1, 1953

By E. P: Mathewson

Discussion of the paper of E. P: Mathewson, presented at the Butte Meeting, August, 1913, and printed in Bulletin No. 78, June, 1913, pp. 1033 to 1037. PROF. JOSEPH W. RICHARDS, South Bethlehem, Pa. :-Speaking to the question of the development of the basic lining, and speaking from a somewhat considerable study of the history of the process, ,I think Mr. Mathewson's conclusion (in the last paragraph. of his paper) is perfectly justified and is very fairly stated. Messrs. Smith and Pierce worked at developing their process for many years ; copper men had been trying their level best to get away from the silica lining of the converters and had uniformly failed. On one page of Mr. Mathewson's paper we read that at the old works of the Anaconda Company, at Anaconda, the experiments " were abandoned on the score of cost and lack of advantages." On the next page, after describing the work of Messrs. Smith and Pierce, we have the statement that the Anaconda Company lined a shell with mangnesite brick and the ?results were excellent." I think Mr. Mathewson's statement that to Smith and Pierce belongs the credit of developing a long-discredited idea, is correct. C. D,. DEMOND, Anaconda, Mont. :-It seems to me that the matter of the lining is important; my impression is that they used tar in their basic lining and that did not seem to be at all successful at Anaconda, but silicate of soda was very successful. MR. RICHARDS :-I did not know that they- had abandoned the use of tar. MR. DEMOND :-I said I thought that was the practice. At Anaconda that was not at all satisfactory in the basic linings. Silicate of soda was very satisfactory and is so.

Jan 11, 1913

By S. K. Tarby, W. O. Philbrook

The rate of FeO and MnO reduction from silicate and aluminate slags by carbon-saturated iron is dependent on both slag composition and temperature. Owing to variable stirring rules during- the course of reaction, the reduction processes occur in two stages in stationary graphite crucibles. In the first stage the slirring caused by CO evolution results in forced convection conditions in the slag. As the boiling action subsides during reduction, the flow conditions within the system become those defined by natural convection. Analysis of the data by an unsteady-state penetration model indicates that the rate of reduction is controlled by the rate of cocur-rent flow of' cations and anions from the bulk slag to the interface during both stages of reduction. The hearth reactions of the blast furnace have been extensively investigated from the viewpoint of equilibrium by deductions from controlled laboratory experiments. However, the literature contains relatively few studies that have been directed toward the area of slag-metal reaction kinetics, and the majority of these have been concerned with the rate and mechanism of sulfur transfer between iron and slag. More recently, attention has turned to the kinetic factors in the reduction of oxides from liquid slags. One of the first investigations in this field was conducted by Dancy1 on the reduction of pure liquid FeO and pure liquid Fe3O4 by carbon-saturated iron. The integrated form of the rate equation indicated that the reduction of FeO was of the first order up to 80 pct reduction. Over the initial 30 pct of reduction, the magnetite reaction was also interpreted as a first-order process. The rates of reaction were extremely rapid as indicated by a 30 pct reduction of the liquid magnetite in a time interval of about 1 to 2 sec. Phil-brook and irkbbride' studied the reduction of FeO from a lime-alumina-silica slag by carbon-saturated iron and solid graphite in stationary crucible assemblies. With the use of the differential form of the rate equation, the rate of the reduction reaction was found to be proportional to the second power of the concentration of the reactant FeO for both the slag-metal and slag-graphite reactions. These authors presented a number of comments in an effort to explain the difference between the molecularity of the above reaction and the observed second-order relation. One such argument, recently extended by Wagner,3 was that the rate-limiting step may well be one of transport control. A complete discussion of the proposed mass-transport control mechanism of this reduction reaction will be presented in a later section of this paper. Kinetic studies of the reduction of other oxide species, namely chromous oxide, titania, and silica, have also been reported. McCoy and philbrook4 used rotating crucible assemblies to investigate chromium reduction from Ca0-SiO2-A12O3 slags. First-order kinetic law was obeyed for the slag-metal reduction reaction as determined by the integration method of data analysis. Due to scatter of the data, any dependence of the rate constant on temperature or slag composition was obscured. Concentration-time data for the reduction of titania from blast-furnace type slags under reducing conditions were obtained by Delve, Meyer, and Lander.' The data were too few, however, for a formal kinetic interpretation. Kinetic data for the very slow reaction of silica reduction have been observed by McCoy and Philbrook6 and Fulton and chipman.7 The former experimenters found the reaction-rate constant for silica reduction by carbon-saturated iron to be 20 to 60 times less than the rate constant for chromium reduction. In their work on the reduction of SiO2 in mechanically stirred systems, Fulton and Chipman also found small values for the specific reaction rate and derived a high value for the energy of activation for the reaction. In both of these investigations, the reduction process was assumed to follow first-order behavior. schuhmann8 proposed that the rate-limiting step in this reaction is the diffusion of oxygen from the interface through a boundary-layer film to the bulk metal phase, and Rawling and Elliott9 have reported experimental confirmation of this hypothesis for temperatures below 1600°C. Turkdogan et a1.10 have also concluded that the rate of reduction of silica is a slow process and controlled by the diffusion of oxygen in the metal, but only in the absence of carbon monoxide bubbles at the slag-metal interface. In the presence of bubbles, achieved either by injecting carbon monoxide at the slag-metal interface or by blowing it through the metal and slag, these investigators found a rather rapid reduction of silica which appeared to be controlled by an interfacial reaction involving the de-sorption of silicate ions from the slag-metal interface to the metal phase as silicon and oxygen atoms. In view of the unresolved nature of the kinetics of FeO reduction and the lack of kinetic data for the manganese reaction,

Jan 1, 1968

By Sidney G. Parker, Jack E. Pinnell

Cubic ZnSe crystals have been grown with HCl, HBr, and I, as chemical transport reagents. The growth of large, well faceted crystals is in the order HCl < HBr < I, with some produced by I, transport being 1 cm on an edge. ZnSe:I crystals showed no strain in cross polarized light and were homogeneous as determined by electron microprobe. These ZnSe:I crystals had a mobility at 25°C of about 300 sq cm per v-sec and contained 103 dislocations per sq cm; further, these crystals were pure cubic and showed both photolumi-nescence and photo conductance. Doping was attempted during crystal growth. ZnS and Zn (S,Se) crystals were also grown by I, transport. ZnSe crystals have been grown by most of the common techniques.1"6 Of these, chemical vapor transport as developed by Kaldis2 showed promise of producing high perfection, cubic ZnSe. With chemical transport, crystals can be grown far below the transition temperature for conversion of cubic to hexagonal structure. A small temperature gradient between source and growth region tends to allow near equilibrium growth, which should lead to good crystalline perfection. Because it is necessary to form volatile compounds, halogens or their compounds are extensively used as transport agents. HCl, HBr, and I, were compared as transport agents for growth of ZnSe crystals. Doping during crystal growth was attempted. ZnS and ZnSxSe1-x crystals were also grown by chemical transport. Electrical and optical properties of the crystals were examined. EXPERIMENTAL Fig. 1 is a sketch of the growth apparatus, which was a modification of Kaldis&apos;. A quartz rod which butted against the seed crystal served as a heat sink to promote growth only on the seed. Initially, crystal growth was attempted with ZnSe prepared by wet chemical methods. Because such a material contained oxides and selenates, HC1 reacted with these oxygen compounds to form H2O and no ZnSe transport occurred. Further, this ZnSe contained about 10 ppm Cu plus other impurities. High purity ZnSe, containing small amounts or no oxygen compounds, was prepared by reaction of H2Se with zinc vapors at 600° to 800°C in an atmosphere of palladium diffused H2.7 The ZnSe thus produced was usually copper free and contained only 1 ppm by weight of magnesium as determined by emission spectrographic analysis. G.E.&apos;s electronic grade ZnS, which had about 10 ppm metallic impurities, was used without further treatment. ZnS-ZnSe charges were prepared by mixing the two compounds together, then sintering 24 hr at 1100°C in an H2S ambient. The gases, HBr and HC1, were commercial grade, of 99.9 pct purity, while the I2 was 99.999 pct pure. The single crystal seeds with (111) faces for growth were mechanically held in place by sealing the outer quartz tube to the growth tube. After the charge was introduced, the system was outgassed at l0-5 torr while heated to 500°C. The desired quantities of transport reagents were then sealed off in the system, which had been cooled to 25°C. The growth tubes were inserted into a furnace with the desired temperature and thermal gradient. The system was allowed to cool for 1 to 12 hr from growth temperatures of about 850" to 25°C. The tubes remained stationary during crystal growth. HCl CHEMICAL TRANSPORT GROWTH Preliminary runs with HC1 had a temperature gradient of 100° to 200°C and no seed or heat sink. Only small crystals were obtained in these experiments as

Jan 1, 1970

By M. P. E. Desvaux, P. Charsley

OLIP-line observations on copper alloys, using the electron microscope, have been made by a number of workers,13 but this work has been confined to a brass. In a CuAl alloys Koppenaal4 and Koppenaal and Fine5 have made observations with the optical microscope and by the use of interferometry. They found that the observed slip step heights inside the Liiders bands accounted for only 42 pet of the total macroscopic strain. The suggestion was put forward that optically unresolvable slip in other parts of the specimen accounted for a major part of the macroscopic strain. This is surprising since it is known from other workers that slip in a brass is inhomogeneous; i.e., large amounts of slip occur on individual {lll) closelys paced than being shared by a large number of closely spaced planes. Furthermore, a brass and a CuAl alloys with high concentration of aluminum exhibit similar deformation characteristics and slip-line patterns. Prior to investigations into the behavior of copper and a CuAl alloys under reversed stresses in tension and compression, some preliminary experiments have yielded results which the authors think resolve this discrepancy, and throw some further light on the behavior of a CuAl in tension. An experiment was carried out on a 10 at. pet CuAl single crystal, of gage length 7.5 cm, diameter 3.1 mm, and orientation shown in Fig. 3 (inset), for the purpose of resolving the above discrepancy. The specimen gage length was electropolished for 10 min in a 50:50 orthophosphoric acid (SG=1.75)-distilled water system, with 2 v across the cell and a current density of 0.5 amp per sq cm. The cathode was made of copper. After a tensile strain of 0.067 ± 0.001, intense slip was observed over a length 2 cm of the gage length whilst the rest of the specimen was relatively undeformed. In the lightly deformed region, slip bands of mean width 20 /x were spaced about 1 mm apart on average. The transition from the heavily slipped region (usually called a Liiders band) to the lightly deformed region was gradual, the slip-band density increasing as the "Liiders band" was approached. In the latter, the slip bands became so close together that, to the naked eye, the specimen appeared to be continously slipped, and the typical microtopography of this region is shown in Fig. 1. Twelve electron micrographs were taken at random from replicas of the Liiders-band region, and the widths of the slip lines were measured. The slip lines account for an over-all tensile deformation of 7.0 ± 0.7 pet, after allowing for the lengths of the un-slipped regions, which is in good agreement with the macroscopic strain. The distribution of slip-line widths was also measured and is shown in Fig. 3. Since Koppenaal could not resolve slip lines with height less than 540A (limit of resolution represented by dashed line), then it was deduced that he could have measured only about 50 pet of the deformation within the &apos;Liiders Band&apos;. It is concluded, contrary to the suggestion of Koppenaal,5 that virtually all the macroscopic strain is accommodated within the "Luders band" and that there is no need to invoke fine slip distributed uniformly over the gage length.

Jan 1, 1967

By Kendall Y. Keuhey

The Mercur Mine, developed and operated by Getty Mining Company, is designed to process 3,000 tons/day of gold ore from the historic Mercur Hill mining district. The mill process involves crushing, grinding, and cyanide carbon-in-leach for recovery of gold from ores ranging from 0.08 to 0.10 oz/ton. During the mining of normal grade ore, a substantial tonnage of material containing 0.02 to 0.05 oz/ton is mined and would be available for heap leaching. Also, Getty Mining is developing methods to test and prepare lower grade material for heap leaching by rejecting a coarse rock fraction from the grinding SAG mill circuit. This lower grade fraction is suitable for heap leaching, and its removal will upgrade the regular mill feed. Other test methods are directed toward leaching techniques on some 4.0 million tons of tailings that resulted from roasting and/or cyanide leaching Mercur ores in the early 1900&apos;s. The natural carbons associated with the Mercur deposits require special treatment to reduce their gold adsorption effects when leached with cyanide.

Jan 1, 1984

By E. A. Holbrook

RESEARCH, primarily, is finding out the truth. Research applied to engineering opens the door to new principles and processes, the application of. which benefits mankind in a material way. The engineer believes that investigation instituted with the primary view of making the results directly applicable to the industries is the highest type of research. Coal is essentially the basis of modern industrial civilization; therefore, any, considerable research pertaining to coal must link itself to the industry by, practical application of the results of the research. In other words, all investigational work connected in any way with coal leads to conclusions that permit a better understanding of the origin, nature of occurrence, composition, better and safer mining, more careful preparation, or greater efficiency in utilization of coal. Modern engineering research has been fostered essentially by universities and in the laboratories of institutions of learning. Coal problems that lend themselves to solution in the laboratories have been first attacked and are perhaps the farthest toward solution. For example, a great amount of research work has been carried out with the various phases of chemistry connected with coal. On the other hand, the equally important problems connected with methods of mining have received but little attention, primarily because their solution involves the continued use of a great and expensive laboratory, which is none other than the mine itself. As many of the problems already solved have had chemistry as their background, so many of the problems unsolved have physics as their background; there are also unsolved problems that deal in- coal economics. Even psychology must be called upon in future coal-mining research as a basis for solving those great problems that deal with human relationships. In general, considerable advance has been made in coal research dealing with chemistry, not so much progress has been made with problems having physics and engineering as a background, while there is a tremendous range of untouched problems that deal essentially with business and psychology.

Jan 9, 1919

By M. M. Austin

Pure metallic tantalum, from a practical standpoint, is one of the newer developments in the metal field. Although it was used as filament in incandescent lamps in 1906, only within the last, five years has the metal been available in sufficient quantity and suitable form for more general application. In addition to corrosion-resisting properties and high melting point, the metal has an ability to withstand unusual amounts of cold working. It affords some striking demonstrations of block movement during plastic flow. Strength and Ductility of Tantalum Since there is no good way of defining working properties numerically, illustrations will be used. It is possible to roll a bar of pure tantalum 0.4 in. thick to sheet 0.001 in. thick, without heating or annealing. The sheet produced will be sound and may be bent upon itself at right angles to the direction of rolling. Longitudinally the sheet will be somewhat brittle. A disk of annealed metal may be cupped and drawn to the form of a capsule 3/16 in. dia. by 146 1? in. long. If carefully handled this capsule can be further deformed by drawing to a tube having an outside diameter of 0.050 in. Disks of tantalum may be spun into tubes of 39 in. dia. and 1½ in. long. In the form of rod, reductions may be made from 0.4 in. to 0.001 dia. In the latter process, it is necessary to heat the wire four or five times to 500" C., at intervals between 0.040 and 0.001 in. Although the melting point of tantalum is 2850" C., these heatings at 500" C. are sufficient to distinctly anneal it. Published figures on the strength and ductility of tantalum are not particularly accurate. This is due to the fact that these properties vary widely, depending on the extent to which the metal is contaminated by gas. There are no sharp critical points in these changes with gas content; samples of metal will vary from a springy or actually brittle condition to one of leadlike softness. Samples that have had a prolonged heating at high temperatures in a good vacuum, under conditions such as would be provided in vacuum-tube experimentation, will yield a product of about the hardness of annealed copper. The usual commercial metal will have the hardness of annealed mild steel.

Jan 1, 1930

By R. H. Marshall, J. Welchner, E. S. Rowland

THIS paper presents results on an exten¬sion into the realm of high-carbon steels of some work recently published&apos; on the effects -of time at temperature, quenching temperature and prior structure on the hardenability of one 0.20 and four 0.40 per cent carbon alloy steels. It was shown at that time that unless the conditions of time, temperature and prior structure are substantially the same in performing the hardenability test as in conducting harden¬ing of parts in production, the correlation of hardenability information with the [ ] hardness and properties of production parts is often not of satisfactory accuracy. The general effects of these variables on the austenitic grain size, distribution of excess carbides and critical cooling rate have been known for many years and one or more have been investigated by Shepherd ,2 3 Davenport and Bain,4 Digges,5,6 Digges and Jordan,7 Post and associates&apos; and Roberts and Mehl,9 to mention only a few. There has been no systematic investigation, however,&apos; into the quantitative variations produced on the hardenability of commercial high¬carbon steels by changes in these factors of time, temperature and prior structure. PROCEDURE A plain carbon hypereutectoid steel, S.A.E. 52100 and Graph-Mo, a molyb¬denum-bearing high-carbon steel contain¬ing some graphite, were chosen for this investigation. The chemical analyses of these electric-furnace steels are given in Table I. [ ] The procedure used was exactly that reported previously,&apos; hence the details will not be repeated here. Normalized (1650°F.) and spheroidized prior structures were utilized on all steels with hot-rolled and quenched (1600°F. oil) prior conditions added for the plain carbon steel. The end-quench test developed by Jominy10 was selected for use in this investigation and, with the noted exceptions, the American Society for Testing Materials standard. procedure was followed. The effect of time at temperature was examined at intervals of 0, 10 and 40 min. and 4 hr., and a few i6-hr. tests were run. Salt-bath heating of the specimens was employed to control and minimize the

Jan 1, 1944

By H. V. Fairbanks

This report covers a study of three different methods for drying ultrafine coals by sound waves. Ultrafine material is classified as coal which passes through a 100-mesh sieve. During the investigations, it was found that the addition of acoustic radiation to the drying of ultrafine coal is effective in increasing the rate of drying; the effect of acoustic radiation to improve drying decreases with an increase in the temperature of the system; the drying rate increased 10-40% when acoustic radiation was introduced into a rotary kiln but was dependent upon the environmental conditions; the application of vertical vibrations to multi-tiered drying screens increased the rate of moisture removal ten times over that obtained in the rotary kiln; the formation of coal balls in any of the drier systems retards the rate of drying; the higher the initial moisture content of the coal the greater the amount of coal balls formed.

Jan 1, 1970

By Frederic E. Carter

There have been many attempts to prove that platinum was known to the ancients, but since no traces of the metal have been found in the relics of early times, it must be concluded that it was not known to them. As far as records go, it was actually first discovered in the 16th century in a Spanish mine on the Pinto River in South America; from which source it received its name of Platina del Pinto (little silver from the Pinto). It was more or less of a rarity and was a subject of interest to a few chemists only, until the year 1822 when the metal was first discovered in Russia. In 1819 there were noticed in the washings of the gold sands of the southern part of the Ural Mountains, grains of a heavy white substance, but it was not until three years later that this substance was found to contain platinum. While at first the amounts of platinum brought from the Urals were meager, prospecting soon disclosed rich deposits extending over a considerable area, and nuggets from 10 to 20 lb. were by no means rare. This discovery assured to chemists an ample supply of platinum for their crucibles, etc. The ore is now found in various parts of the world but the richest deposits are still found in the Ural Mountains. The platinum of commerce is obtained entirely from alluvial deposits at depths varying from 6 to 40 ft. The sand and gravel of former river beds are subjected to a series of screenings and washings to effect the separation of the ore. Actually, probably all gold-bearing gravel beds of the world contain platinum, and it is more than likely that large quantities of platinum ore have been thrown away with the black sand washings from gold placer deposits. This is especially true of the alluvial deposits of the Pacific Coast in California and Oregon. Platinum ore is usually found in the form of rounded or flattened grains of "sand," and occasionally in irregular lumps of the size of peas. Large nuggets are very rare. The ore has a metallic luster and is distinguished by its steel gray color, but shows light gray streak when rubbed on a hard white surface; it has a high specific gravity, 16 to 19; is infusible in the hottest blast furnaces, and insoluble in any single acid. Platinum ore is a complex body consisting of the metal in combination with varying proportions of the other members of the platinum group; iridium,

By David R. Poirier

Activity data of carbon as a function of both temperature and composition throughout the stable austenite range is correlated by mearts of an equation derived from a quasi-chemical model. The carbon activity data of austmite for temperatures between 800° and 1200°C are utilized in conjunction with the activity of carbon calculated for the y solidus using the activity of carbon in liquid iron and published austenite-liquid equilibria. The results agree very well with Chip-man&apos;s correlation; however, a small difference in the activity of carbon in the high-temperature range of the austenite field is evident. Excellent agreement is found for the heat of solution of graphite in infinitely dilute austenite; from this study the value is 10,550 cal as compared with Chipman&apos;s value of 10,680 cal. AS part of a program to study microsegregation in dendritic solidification of ternary Fe-C-Cr alloys, it was desirable to be able to describe the equilibria between austenite and liquid iron in Fe-C-Cr alloys. In this regard, it was necessary to correlate existing data on the activity of carbon in Fe-C austenite as a function of both temperature and composition. At that time, Chipman&apos;s analysis1 of the thermodynamics of binary Fe-C austenite was not available. It will be shown that this study and Chipman&apos;s study agree rather well throughout the stable austenite range of temperature and composition; however, some small differences appear at temperatures greater than the eutectic temperature. Benz and Elliott 2 presented isoactivity lines for austenite superimposed on their revised Fe-C phase diagram. Using an expression from Darken and Gury 3 representing Smith&apos;s4 activity data between 800" and 1000°C, they found that the activities extrapolated above 1000°C to the solidus did not agree with the activities determined from the corresponding liquidus compositions. It is the purpose of the following argument to reconcile carbon activity data of austenite with the activity in liquid Fe-C alloys as determined by Rist and Chipman. 5 In addition, a simple analytical expression is sought for computational convenience. ACTIVITY DATA OF CARBON IN ZRON Fig. 1 shows the activity of carbon in Fe-C austenite as determined by Smith, 4 Schenck and Kaiser, 6 Scheil et a1.,7 and Bungardt et al.&apos; The lines are merely drawn to separate the data into the respective isotherms. These data are inadequate to determine the activity of carbon at temperatures greater than 1200°C. The activity coefficient in Fe-C liquid alloys was assumed by Rist and chipmans to obey the following

Jan 1, 1969

By L. W. McKeehan

THE occurrence of twins in large ferrite crystals, made by a new process, was reported in a recent note.1 This paper describes a typical case of such twinning and suggests, on the basis of the observed facts, why smooth slip-planes are rarely observed in this metal. METHOD OF PREPARATION The material in. which the crystals here dealt with were grown was made from 1/8-in. Armco iron welding rod containing C, 0.04; S, 0.037; P, 0.003; Si, 0.008, and Mn, 0.02 per cent. This rod was cold drawn into wire about 1 mm. dia. A piece of this wire was supported vertically and was locally heated in hydrogen at atmospheric pressure to about 1400° C. by an alternating current (60 cycles per sec.) of about 35 amp., passed through it between a pair of traveling contacts about 8 cm. apart. The rate of travel for the case in hand was 12 cm. per hr. After some 30 cm. of the length of the wire had been heated and cooled in this manner the whole wire was immersed for a few seconds in dilute nitric acid, not restrained by alcohol. Etching was continued until, ass nearly as could be judged by eye, the original smooth cylindrical surface of the wire was no longer capable of specular reflection. MEASUREMENTS The wire in the etched state was next mounted in a goniometer of special form which allowed the measurement of the spherical coordinates of the normals to any plane surfaces left by the etching. These coordinates were most conveniently a polar distance, ?, from one direction of the wire axis, and an azimuth or longitude, [ø], from an arbitrary prime meridian. The region to be described more particularly is shown at a low magnification in Fig. 1, which gives two different views, differently illuminated to show the spatial relationship of a crystal occupying most. of the part shown and of an inclusion, or rather a series of three inclusions suspected of being twins based on the principal crystal.

Jan 1, 1928

By William Hurst

Muskat&apos;s depletion performance equation is here derived considering the expansion behavior of the reservoir hydrocarbon system and a simple fractional-flow equation. This nietkod of derivation leads logically to the two extensions that follow. The first of these is concerned with gravity segregation in a depletion-drive reservoir. The second is concerned with including an empirically determined tern? for water influx in the performance equation. The more general equation for gravity segregation when there is a primary gas cap and empirically-determined water influx is stated for completeness. These equations have been found useful in reservoir performance calculations in Eastern Venezuela. A discussion on the methods of solving these equations follows, and considers firstly the effect of taking finite intervals in the numerical integration, and sec-ondly, methods of incorporating the time functions involved in segregation in with the expansion behavior. The paper concludes with a brief general discussion on further extensions to the depletion performance equation. INTRODUCTION The two fundamental sources of energy by which oil is produced from a reservoir result from pressure depletion inside the boundaries of the reservoir and fluid encroachment across the boundaries of the reservoir. The wells in either case form low pressure outlets through which oil and gas may be produced by the expansive force of the reservoir fluids and associated encroaching fluids. When the reservoir pressure is higher than the bubble-point pressure of the oil, so that there is no free gas in the reservoir, these expansive forces are the only ones available for the production of oil. However, when the reservoir pressure is less than the bubble-point pressure of the oil, free gas is vaporized as the pressure falls. With both oil and free-gas phases present, the additional forces of gravity and capillarity may operate on the gas-oil system, as they have previously operated on the oil-interstitial water system. Gravity tends to segregate the free gas from the oil due to their density difference. Capillarity opposes and eventually balances gravity as the more extreme free gas and oil saturations are reached, preventing the independent move- ment of free gas until it is above a certain saturation, and the independent movement of oil when it is below a certain saturation. The type of depletion performance equation chosen for predicting the future performance of a reservoir depends on the amount of past history available. When the reservoir is somewhere past the halfway mark in depletion, some form of decline curve is often used. With less past history, material balance equations which incorporate empirical factors based on the past performance are often used. When, however, the amount of past history is small, the Muskat depletion performance equation will usually be used. The distinguishing feature of this type of equation is that empirical factors based on the over-all or macroscopic reservoir behavior are almost or entirely absent. Each parameter affecting the reservoir performance is ascribed an independent set of values based on measurements made on laboratory samples; that is, incorporating microscopic empirical factors. In establishing Muskat-type depletion performance equations, it is necessary to consider the reservoir as consisting of a number of associated blocks, in each of which the saturations and pressures may be considered uniform, and in each of which all substances have uniform pressure-volume characteristics. Thus, a primary gas cap can usually be considered as one block and an aquifer as another. Gravity segregation may be negligible for practical purposes when the rock and oil properties are adverse and/or the dip or thickness of the reservoir is too small. In this case the whole oil leg may be considered as one block, except in very large reservoirs. In very large reservoirs the fluid and rock properties may vary enough, particularly in the dip direction, for it to be necessary to divide the oil leg into a number of blocks, in each of which the relevant quantities may be considered uniform. When gravity segregation of the oil and free gas is not negligible, it is necessary to consider the space occupied by the initial oil leg as divided into two blocks, a secondary gas cap and an effective oil leg, in each of which saturations may be considered to be uniform. The total volume of these two blocks is thus constant, but the secondary gas cap grows continuously at the expense of the oil leg. Muskat1 derived depletion performance equations for the basic case of an oil reservoir with closed boundaries and without segregation, and for the case of an oil

By M. C. Flemings, F. R. Mollard

Conditions necessary for plane front growth of two-piwse solids from a single-phase melt are discussed. Alloys consideved are those from a simple binary system containing a eutectic, but are not, in general, of eutectic cornposition. It is concluded that: 1) plane front solzdification is favored by low growth rate, steep thermal gradient, and essential absence of convection; and 2) for steady-state solidification, the structure should resemble that of directionally solidified eutectics (lamellar, rodlike). Factors affecting THERE are many materials, including metals, available today with strengths in excess of 10&apos; psi when in whisker or fiber form. The challenge facing those interested in practical application of such materials has been, and remains, the economic production and incorporation of the whiskers or fibers into useful engineering composites. solute redistribution along the growth direction are described quantitatively, by numerical solution of the diffusion equation. Effects of variations in growtlz rate on average composition of the solidifying composite are significant. For alloys not too close to a single-phase region, the initial transient at constant gvowth velocity is the order of D/R where D is diffusion coefficient in the liquid and R is interface velocity. Composites consisting of the reinforcing phase within a metallic matrix have excited particular interest in recent years because of their potential for high strength at elevated temperature and for resistance to brittle fracture. Techniques employed to incorporate the whiskers or fibers in the metallic phase have included 1) liquid metal infiltration, 2) solid or liquid phase sintering, and 3) direct growth of composites from the melt, of rodlike or lamellar morphology, by directional solidification of eutectic alloys. Two recent books"2 have reviewed the status of this growing field. Concerning the last method, growth of eutectics, it has been shown that the reinforcing phase (e.g., rods)

Jan 1, 1968