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By NATHANIEI HERZ

(Cleveland Meeting, October, 1912.) THE formula very frequently used for computing the economical size of pipe to transmit compressed air is that of D'Arcy, as follows: d5(p1-p2)/w1l D-c w11 Where, D = the volume of compressed air delivered in cubic feet per minute,-at the final pressure. c = an experimental coefficient determined for the various sizes of pipe. d = the diameter of the pipe in inches. 1 = the length of the pipe in feet. P1 = the initial gauge-pressure in pounds per square inch. p2= the final gauge-pressure in pounds per square inch. W1 = the density of the air, or the weight in pounds per cubic foot at the initial pressure, p,. The most common case is that in which the given quantities are: the quantity of air required, the length of the pipe, and the initial pressure. The method of solution is to assume a pressure-loss and to compute the remaining factor, c/d5, thus giving the size of pipe corresponding to the assumed loss of pressure. It is always desirable to try two or more pressure-drops, in order to find the combination that is most satisfactory, since often a small change in the size of pipe will reduce or increase the loss of pressure several pounds. An alternative method is to assume a size of pipe and calculate the corresponding pressure-drop. Each method involves a series of tedious calculations to arrive at the most economical solution, and also requires the use of tables giving the constant, c, the actual diameters corresponding to the nominal pipe-sizes, the density of the air, w1, and often, for convenience, a table giving the

Dec 1, 1912

By J. W. R. Rayner

THE conventional method of making water gas involves individual plants for the separate carbonization of coal to coke and the subsequent gasification of coke with steam. The process demands lump coke, preferably made from the best quality of coking coals. The ash in the coke should have a high melting point and the gasification process suffers a loss of efficiency when cokes with low ash-melting points are used. In Britain, these coals are generally the most expensive and they are readily available only in certain localities. The coals not suitable for making lump coke, or yielding only poor quality coke, are much more widely available and are generally cheaper. DEVELOPMENT OF ALTERNATIVE PROCESSES In Germany, processes have been developed and operated commercially for the production of water gas from very low-rank coals such as brown coal and lignites, but much less effort has been spent on processes to use coals of intermediate rank, which are widely available in Britain. The brown-coal processes use coal in the form of either dust or briquettes. The most successful of the dust-gasification methods is the Winkler process, which made a substantial contribution to German oil production during the war. It uses coal in the size range 0 to 8 mm and the fuel bed is blown with a mixture of oxygen and steam at a rate high enough to give it a characteristic boiling motion or, in present-day phraseology, at a rate more than sufficient to fluidize it (Fig. 1). Air cannot be used to provide the heat required for gasification, for vari¬ous reasons. In the first place, to make the process continuous by mixing air and steam would involve the production of a lean gas containing much nitrogen. If a separate blow were used, a large amount of potential heat would be lost because the blow gas in such a process would contain a very high percentage of carbon monoxide. Oxygen is necessary therefore and oxygen remains relatively expensive for use in gasification. In the Winkler generator, formation of clinker caused by local overheating does not occur, because of the mobility and high heat transfer of a fluidized bed. These properties of fluidized dusts have been used most successfully.

Jan 1, 1953

By Paul M. Tyler

MARKETWISE the year 1935 was rather a good one for most of the rare and minor metals; as a class they climbed out of the depression much faster than the common metals. The diamond market, too, was better than it had been for years, attributable only in part to investment buying, as there was a genuine pick-up in consumer demand. Wars and rumors of war tended to speed up purchases of certain metals, but consumption for peaceful purposes was the principal factor. Significant was the important role played by new industrial uses. New discoveries during the year were disappointingly few, considering the broad extent of this research frontier. Scientific developments were far from being at a stand-still, of course, but the dominant note was the cashing in on research consummated in former years. With even a moderate upturn in general business a surprising number of laboratory ideas donned overalls and found jobs in industry.

Jan 1, 1936

By E. T. Knight, John D. Gill

IN ITS capacity for service to the public the oil industry is truly gargantuan. But it is only in this respect that the industry is the voracious, many-headed, many-armed and many-handed creature it has been so often painted by those who know it not too intimately and only from the outside. Contrasted sharply with the immensity of the service rendered is the relatively modest share of the national income which has gone to those who provided the tools and the mental and manual labor with which the service was performed. No doubt the relative meagreness of the re- ward was the result of a combination of fortuitous circumstances respecting the nature and accessibility of the industry's raw material and the extensive development and application of the most advanced technology, spurred by an intense competition.

Jan 1, 1940

The following officers were elected by the Pennsylvania Anthracite Section of the A. I. M. E. on the evening of June 28th. Chairman, R. V. Norris; vice-chairmen, C. F. Huber, W. G. Whildin, W. J. Richards, Eli Conner; executive committee, Douglas Bunting,. W. W. Engle, Chas. Enzian, J. M. Humphrey, A. B. Jessup, R. A. Quinn; secretary and treasurer, Paul Sterling.

Jan 9, 1919

By J. C. Williams, M. J. Blackburn

Several of the decomposition processes that can occur in supersaturated phases in a Ti:11.6 wt pct Mo and a Ti:20 wt pct V alloy have been studied by transmission electron microscopy. The deformation induced "marternsitic phase" in the Ti:Mo alloy has been found to have a bcc or bct structure rather than the previously reported hexagonal structure. The morphology of&apos; the transformed region is a rather complex asserrlblage of twins, twinning occurring in one or more systems; this internal twinning has been found to occur on (112). The w phase is formed in both alloys on aging and is present in the Ti:Mo alloy after quenching. The structure of this phase has been confirmed as hexagonal in both systems, however, differences in morphology and stability are found between the two alloys. Thus in the Ti-Mo alloy the w phase has an ellipsoidal morphology with the major axis lying parallel to <111>ß or [0001]w while in the Ti-V alloy the phase forms as cubes, the cube faces lying parallel to {100}ß or {2021}w Some observations on the particle sizes, volume fraction, and composition of the w phase in the Ti-Mo alloy are listed. The mode of formation of The a phase from the (ß + w) structures is also different in the two alloys. In the Ti-Mo alloy the a phase is formed by either a cellular reaction or by the growth of isolated needles, whereas in the Ti-V alloy the a phase is nucleated at an w:ß interface and grow to consume the w phase. Some of the difjerences in behavior of the w phase are attributed to the mismatch between it and the solute enriched ß matrix in which it forms. MaNY transition elements tend to stabilize the bcc or ß-phase when added to titanium. In general two types of phase diagrams are produced, either a ß-stabilized (ß-isomorphous) system, e.g., Ti:Mo, -Ti:V, Ti:Nb, or a ß-eutectoid system, e.g., Ti:Cr, Ti:Fe, Ti:Mn. In previous papers&apos;-4 the phase transformations in the a-phase and (a + ß)-phase alloys have been described and this work has been extended to ß-stabilized systems. Specifically, transformations in the alloys Ti:20 wt pct V and Ti:11.6 wt pct Mo have been studied; in both of these alloys the ß phase is retained at room temperature when quenched from the ß-phase field. A number of phase transformations can occur in such metastable ß phases and the two alloys were chosen to include most of the transformations reported for ß-stabilized systems. We list these possible phase transformations below. Ti:11.6 Mo quenched from >780°C to retain the ß phase: a) The w phase can form on quenching.5 b) Martensite can be produced by subzero cooling or deformation. Two martensite habit planes have been reported in Ti:Mo alloys; (334)ß and (344)ß=6 c) On aging at temperatures <-550° C the w phase is formed before the a-phase.5,7 d) On aging at temperatures >550°C the a phase is formed.7 e) The martensite can be tempered. It has been reported that the a phase rather than the ß phase is precipitated during tempering.&apos; Ti:20V quenched from >660°C to retain the ß phase:9 a) At aging temperatures <260°C separation into two bcc phases occurs. b) The w-phase is produced prior to the a phase on aging at temperatures <-400°C. c) At temperatures 2400°C the a phase is formed directly. T-T-T diagrams describing the temperature and time regimes for the formation of these phases have been published7,9 for a Ti:12 pct Mo and a Ti:20 pct V alloy. We have attempted to investigate these transformations using transmission electron microscopy, however thin foils undergo a spontaneous transformation in all conditions except the equilibrium (a + ß) structure. This transformation has been reported previ0usly10,11 and we will comment on its morphology and nature in the various sections of experimental results. EXPERIMENTAL The compositions in wt pct of the two alloys investigated were: Ti:11.6 Mo, 0.100 02, 0.006 N2, 0.0015 H2 Ti:20V, 0.0574 O2, 0.0111 N2, 0.005 H2 These alloys were cold-rolled to 0.020 in. thick sheet. Specimens were heat treated in vacuum or in inert gas at temperatures >500°C and in a circulating air furnace at temperatures <500°C. Thin foils were prepared using standard techniques, described in detail previously." Dark field micrographs were obtained using high resolution technique. RESULTS Martensitic Transformation in Ti:11.6 pct Mo. Detailed study of the deformation induced martensite is not possible due to a spontaneous transformation which occurs near the edge of thin foils as shown in Fig. 1. Similar transformations have been observed in iron-" and copper-base13 alloys as well as other titanium alloys, but some observations specific to the Ti:1l.6 Mo alloy are listed below. a) The boundaries of these transformed regions are glissile and move under the influence of the electron beam during examination. b) Selected area diffraction indicates the transformed regions have the same structure as the matrix, being separated by tilt boundaries. The misori-

Jan 1, 1969

THE first session was held in the rooms of the American Philosophical Society, on Tuesday evening, February 26th. The President, Dr. T. Sterry Hunt, called the meeting to order, and after a few introductory remarks concerning the importance of theoretical and speculative science, which often involves principles of the highest economic value, and, more than all that, serves to enlarge our conceptions of the universe, and ennoble us, by the cultivation which it affords to our most exalted faculties, proceeded to discuss some points in the chemistry of the atmosphere. It is known that there is in the crust of the earth a great amount of oxidized carbon, not only in the shape of coal, but also in the graphite or plumbago of the crystalline rocks, in the various bituminous shales or pyroschists, which are found in all succeeding rock-formations, and also in the forms of bitumen and petroleum. All the analogies of nature lead us to conclude that these various carbonaceous substances have had an organic origin, and have been generated by the deoxidation of carbonic acid, a process effected by the growing plant, and attended with the liberation of oxygen. He showed that the carbon of a layer of coal covering the whole earth&apos;s surface to the thickness of one meter, would, in its production from carbonic dioxide, liberate an amount of oxygen equal to that now present in our atmosphere. But bituminous coal contains also a large amount of hydrogen, derived from the deoxidation of water, which implies the liberation of a farther portion of oxygen. The amount from this latter source would equal, for the various coals and asphalts, from one-eighth to one-fourth, and, for the petroleums, one-half of that set free in the deoxidation of the carbon which these hydrocarbonaceous bodies contain. From what we know of the composition of the stratified rocks, it is probable that they include an amount of deoxidized carbon and hydrogen many times greater than that contained in a layer of coal one meter in thickness, and, consequently, that the disengaged oxygen in past ages must have far exceeded that now present in our atmosphere. To this must be added

Jan 1, 1878

The first session was held in the rooms of the American Philosophical Society, on Tuesday evening, February 26th. The President, Dr. T. Sterry Hunt, called the meeting to order, and after a few introductory remarks concerning the importance of theoretical and speculative science, which often involves principles of the highest economic value, and, more than all that, serves to enlarge our conceptions of the universe, and ennoble us, by the cultivation which it affords to our most exalted faculties, proceeded to discuss some points in the chemistry of the atmosphere. It is known that there is in the crust of the earth a great amount of oxidized carbon, not only in the shape of coal, but also in the graphite or plunlbago of the crystalline rocks, in the various bituminous shales or pyroschists, which are found in all succeeding rock-formations, and also in the forms of bitumen and petroleum. All the analogies of nature lead us to conclude that these various carbonaceous substances have had an organic origin, and have been generated by the deoxidation of carbonic acid, a process effected by the growing plant, and attended with the liberation of oxygen. He showed that the carbon of a layer of coal covering the whole earth&apos;s surface to the thickness of one meter, would, in its production from carbonic dioxide, liberate an amount of oxygen equal to that now present in our atmosphere. But bituminous coal contains also a large amount of hydrogen, derived from the deoxidation of water, which implies the liberation of a farther portion of oxygen. The amount from this latter source would equal, for the various coals and asphalts, from one-eighth to one-fourth, and, for the petroleums, onehalf of that set free in the deoxidation of the carbon which these hydrocarbonaceous bodies contain. From what we know of the composition of the stratified rocks, it is probable that they include an amount of deoxidized carbon and hydrogen many times greater than that contained in a layer of coal one meter in thickness, and, consequently, that the disengaged oxygen in past ages must have far exceeded that now present in our atmosphere. To this must be added

Jan 1, 1879

By T. S. Blair

I feel a certain sense of responsibility in bringing before you the subject of the direct process in iron manufacture. I am aware that, in such a body as I have now the honor of addressing, there are few who are not already so well informed upon its past history that it would be a weariness to them to listen to anything else than an account of practical success. Yet, to claim that success involves so much that, if I do not make good my claim, I deservedly expose myself to severe criticism. The whole literature of the art, so far as it relates to the direct process, is, up to this time, but a history of failure. It is safe to say that more money, time, and talent have been fruitlessly spent in the pursuit of this object than in all the other unsuccessful efforts in the whole line of iron metallurgy. A distinguished authority in patent law has remarked that " the invention records of the United States and of foreign countries are filled with the waifs and abandoned relics of these abortive struggles." Dr. Percy, whose great work may be taken as an epitome of all that was worth mention, whether useful or curious, in pig-iron metallurgy, up to the date of its publication (1864), after giving elaborate accounts of various attempts at the direct process, condenses his own opinion of all that had been then effected, into a brief but summary comment upon a pamphlet of one of the sanguine inventors who had said: "It is evident that the present mode of working iron

Thomas Haight Leggett, London, Eng. (communication to the Secretary): Mr. Hammond has given us a concise yet complete description of the Witwatersrand gold-fields, and the character of the operations which have resulted in their remarkable development.

Jan 1, 1902

By Kalervo Rankama

UNTIL a few years ago, geological mapping, the study of ore boulders, and different geophysical methods were the principal means used in the systematic search for mineral deposits covered by a layer of disintegration products or soil. These methods have been developed to a high stage of perfection as far as the geometrical definition of the conductor is considered. Use of geophysical methods in prospecting is based on the fact that an ore body differs from the country rock not only geologically but also in its physical properties. The general drawbacks and complications included in the use of geophysical methods are well known to everyone who has been using them, so need not be entered into here in detail. One of the more important ones is the fact that geophysical methods are unable to furnish information concerning the chemical composition of the ore bodies responsible for the indications. Further, the ores of many metals, such as silver, gold, beryllium, zinc, mercury, tin, lead, vanadium, antimony, chromium. molybdenum, tungsten, manganese, cobalt, nickel, and the platinum metals cannot be directly located by known geophysical methods, owing to lack of physical characteristics suitable for distinguishing them from the country rock. Thus it is quite natural that efforts have been made to develop direct methods for prospecting and locating ore bodies of the elements named. Known as chemical, biogeo-chemical, and geobotanical methods of prospecting, these have been much improved during recent years. A brief review of these methods and of some results obtained with them will be presented in the following, on the basis of available information and my own experience.

Jan 1, 1947

By Paul Sterling

1. INTRODUCTION. THE general impression regarding the preparation of merchantable anthracite is that it is confined to a colossal, grimy structure, called a "coal-breaker." This name is misnomer; for the desired result is not to break the coal, but to prevent its being broken. Preparation may be said to begin at the face of the chamber, with the mining and loading of the coal. Local conditions vary, not only in the same field or basin, but also in the same mine, so that there is no fixed empirical rule governing the method of blasting or cutting coal. Tests should be made, when possible, to determine the explosive, or the mechanical coal-cutter, which will produce the largest percentage of what are locally known as " lump " and " prepared sizes " of anthracite. The prepared sizes are those mostly consumed for domestic purposes. All other sizes might be called by-products of the anthracite industry; for they are not especially desirable, being the degradation resulting from the mining and handling of a brittle or laminated material. Being low in volatile combustible matter, anthracite burns most successfully when nearly of a uniform size, permitting the easy passage of air through the voids. This accounts for the large number of sizes into which the coal is separated. Table I. gives the various sizes, the diameter of ring over and through which each size is made, and the usual purpose for which it is employed.

Oct 1, 1911

By W. A. Backofen, A. T. English

The kinetics of re crystallization were determined metallographically for a 3-1/4 pcl Si-Fe rapidly compressed at temperatures of 710° to 911°C, and held for various times at the working temperature. As in re crystallization following cold wwk, the time for re crystallization was reduced by increased temperature and strain. Nucleation occurred chiefly at grain edges, although other pre-existing interfaces, notably inclusions, also served as nucleation sites. The importance of intragranular nucleation to grain refinement in hot working is pointed out, together with some possible techniques by which nucleation might be induced within the grains. The observed isothermal growth rates are quite accurately described by the equation G = 4 x 10-&apos;/t (cm per sec), independent of temperature and strain at all but the shortest times. Changes in G during recrystalliza-tion can exceed two orders of magnitude. It is argued that release of stored energy associated with lattice defects cannot adequately explain the time dependence. A suggested alternative involves processes of solute segregation and desegregation in the unrecrystallized matrix and at the moving boundary, respectively. EFFORTS to improve hot-working practice are hampered by an incomplete understanding of the fundamental metallurgy involved. Research directed at establishing the required basic foundation falls into two categories, the first concerned with measurement of mechanical properties under the conditions of high temperature and strain rate which characterize such processing, the second focused on structure and its relation to the deformation conditions. Rossard,&apos; Rossard and Blain,2 and Hardwick and Tegart have conducted many high-speed, high-temperature torsion tests on various metals. One of their objectives was interpretation of stress-strain curves in terms of the structures of specimens rapidly quenched following interruption of twisting. They showed that appreciable hardening occurred in the early part of the test, and that this hardening reflected the concurrent development of an increasingly dense substructure within the grains. The detailed nature of this substructure was observed to depend on the ease of polygonization which, at least in fcc metals, varies with the stacking-fault energy.= By holding specimens after interruption but before quenching, the nucleation and growth of new grains could also be studied. Some success has been realized in relating the microstructure of hot-rolled steel to its temperature:strain rate:strain history with such testing.&apos; The same general observations have been made by others investigating rolling4f5 and drop-hammer forging.~-~ Incident to these experiments, some efforts were made to determine the kinetics of re-crystallization as well as the velocity of the migrating boundaries. The results have been largely qualitative, owing to difficulties of interpreting hardness measurements5 and microstructures. The work described here was undertaken to obtain more quantitative information from tests on a material having suitable metallographic properties, and, in this way, to provide further insight into the fundamentals of this practically most important kind of deformation processing. I) MATERIALS AND EXPERIMENTAL TECHNIQUES Materials. Electrolytic etching of a Si-Fe alloy reveals dislocations and substructure in unrecrystallized grains.8&apos;9 This unique characteristic makes possible a precise determination of the extent of recrystallization. For that reason, it was the material selected for all experiments in the present work. The two particular alloys that were used are identified in Table I. A major difference between "A" and "B" is the number of inclusions, as noted in the table. Most of the experiments were made with material "A". It was received as hot-rolled plate 1 in. thick, sawed to 2-in. widths, hot-forged at 1200°C to 5/8-in. rounds, and finally annealed in a mechanical vacuum at 1000°C for 24 hr. The result was substructure-free grains of mean diameter 0.05 cm.*

Jan 1, 1964

By Clarence Zener

Contents Page General Principles................................................................. 551 Equilibrium Diagrams......................................................... 551 Nucleation................................................................... 553 Kinetics of Phase-boundary Propagation......................................... 553 Kinetics of Growth of New Phase............................................... 556 Spheroidization............................................................... 560 Pure Iron-carbon System........................................................... 561 Formation of Pearlite.......................................................... 561 Interlamellar Spacing........................................................ 562 Pearlite C-curve............................................................. 563 Bainite Formation............................................................. 565 Formation of Martensite....................................................... 570 Loss of Tetragonality of Martensite.............................................. 570 Effect of Alloys upon Decomposition of Austenite..................................... 572 Pearlite...................................................................... 572 Bainite and Martensite......................................................... 574 Time-temperature-transformation Curves............................................. 576 Appendix A............................................................. ......... 579 Appendix B....................................................................... 580 Appendix C....................................................................... 580 The present investigation started in an attempt to understand certain details of the decomposition of austenite, and of the effect of alloying elements thereon. As the investigation proceeded it became apparent that not only these details, but all the general features of austenite decomposition, could be understood in terms of fundamental physical principles. Since the direct applicability of these physical principles has not been previously recognized, it was decided to incorporate the original results of the investigation into a review of the general subject of the kinetics of austenite decomposition. This review constitutes the present article. An extended summary of the results is given on pages 576 to 579. This article, which deals with the kinetics of phase transformations, may appropriately be considered as a sequel to two recent articles1,2 from this laboratory on the equilibrium relations in medium alloy steels.

Jan 1, 1947

By Clarence Zener

Contents Page General Principles................................................................. 551 Equilibrium Diagrams......................................................... 551 Nucleation................................................................... 553 Kinetics of Phase-boundary Propagation......................................... 553 Kinetics of Growth of New Phase............................................... 556 Spheroidization............................................................... 560 Pure Iron-carbon System........................................................... 561 Formation of Pearlite.......................................................... 561 Interlamellar Spacing........................................................ 562 Pearlite C-curve............................................................. 563 Bainite Formation............................................................. 565 Formation of Martensite....................................................... 570 Loss of Tetragonality of Martensite.............................................. 570 Effect of Alloys upon Decomposition of Austenite..................................... 572 Pearlite...................................................................... 572 Bainite and Martensite......................................................... 574 Time-temperature-transformation Curves............................................. 576 Appendix A............................................................. ......... 579 Appendix B....................................................................... 580 Appendix C....................................................................... 580 The present investigation started in an attempt to understand certain details of the decomposition of austenite, and of the effect of alloying elements thereon. As the investigation proceeded it became apparent that not only these details, but all the general features of austenite decomposition, could be understood in terms of fundamental physical principles. Since the direct applicability of these physical principles has not been previously recognized, it was decided to incorporate the original results of the investigation into a review of the general subject of the kinetics of austenite decomposition. This review constitutes the present article. An extended summary of the results is given on pages 576 to 579. This article, which deals with the kinetics of phase transformations, may appropriately be considered as a sequel to two recent articles1,2 from this laboratory on the equilibrium relations in medium alloy steels.

Jan 1, 1947

By J. W. Pugh, J. D. Nisbet

THIS study of the ternary has been made as one phase of a metallurgical investigation which began nearly four years ago in the General Electric Company&apos;s Research Laboratory in Schenectady, N. Y. The objective of this program is the discovery of new metallurgical information which will lead to the development of better high-temperature materials. Combinations of the four pure base elements—iron, chromium, nickel, and cobalt—are being studied at the present time. It is essential in an investigation such as this to know as much as possible about the constitutional diagrams involved. The study of the iron-chromium-nickel system has been made to this end. Preliminary Explanation of Experimental Procedure: In all, fifty-five alloys at steps of 10 at. pct were made for the investigation of this ternary. Several ternary alloys in the chromium rich corner had to be omitted because their extreme brittleness made testing impractical. All alloys were vacuum melted with hydrogen reduction and centrifugally cast. The apparatus and technique of this process has been described in detail by Nisbet.1,2 The purity of the alloys prepared in this way is considered to be quite good. Impurities are listed as follows: Pct Carbon.............................0.02 Oxygen................................0.02 Nitrogen.........................0.005 Magnesium..................0.03-0.05 Sulphur...........................trace Hydrogen....................trace Phosphorous..................trace Silicon........................ trace After casting, all samples were given a homo-genization treatment which consisted of holding them for 15 hr at 1150°C (2100°F) and water quenching. Testing was begun with the samples in this condition. The tests employed in the study of this system were (1) dilatometer, (2) hardness versus aging temperature, (3) tensile strength and elongation versus temperature, (4) microstructure analysis, and (5) electrical resistance versus temperature. Dilatometer tests were made at the rather rapid heating rate of 1093°C (2000°F) in one hour on a Bristol-Rockwell type instrument. Hardness data were taken on specimens cooled from 204", 427", 649°, 760°, 871°, 982°, and 1093°C under conditions which are thought sufficient to bring the specimens to equilibrium in all but the cases of the very sluggish transformations. Electrical resistance data for several specimens were taken for both heating and cooling conditions in a vacuum furnace especially designed for this work by D. W. Bainbridge, formerly of this laboratory. Provisions were made for heating and cooling standard specimens at a constant rate, while autographic records of resistance and temperature were made simultaneously. Micrographs of all the alloys were made in the quenched condition. Some question may exist as to how such physical values as hardness, tensile strength, and elongation were interpreted to indicate a change in phase. Original data were recorded on physical property versus temperature graphs, each of which was made from the data of a single alloy (fig. la). From these, another series of graphs were plotted with the physical property as a function of composition for constant temperatures (fig. 1b). Sharp deviations in the slope of these composition versus hardness curves often indicate a change in phase. The example of fig. 1 will serve to describe this experimental technique. The plotting of a single point from graph "a" to graph "b," and finally to the phase diagram "c," is illustrated. The location of the point on graph "b" is indicated as point (1). If all the alloys of the A-B binary system were solid solutions at temperature X, the hardness in this curve would be expected to rise at a fairly even rate as A is diluted with B to a maximum at some intermediate value between A and B, as

Jan 1, 1951

(Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members.) Members and guests who registered at Institute headquarters during the period Mar. 10 to Apr. 10, 1915: Oscar Lachmund, Greenwood, B. C. Harvey B. Small, Mangaugue, Colombia. S. W. Ough, Pachuca, Mexico. M. F. Sayre, Schenectady, N. Y. B. W. Vallat, Detroit, Mich. James W. Hambleton, Parral, Mexico. Charles Mentzel, New York, N. I . Philip L. Gill, Woodmere, L. I., N. 1. M. K. Rodgers, San Francisco, Cal. John T. Fuller is President of the F. Shepherd Mining Co., operating at Rush Mountain, Ark.

Jan 5, 1915

By E. M. Murphy

(Presented by invitation at a meeting of the Spokane Local Section of the Institute, Feb. 17, 1912.) EIGHT years ago the Hecla mine, a lead-silver producer, situated at Burke, Idaho, was producing ore from but two levels, the 300- and the 600-ft. All hoisting was done with a 12- by 16-in. slide-valve, double-reel, hoist. The hoist was being worked to its capacity and was unsuitable for hoisting from greater depths. As the work of opening a new level was about to be started, it became necessary to remodel the then-existing equipment or install a new hoist. The recent advent of electricity from Spokane had made available a cheaper power than steam. By a series of tests conducted throughout the Coeur d&apos;Alène district, it was found that it cost $109 per year to generate a horse-power with steam. Electric power was to be had for $50 a horse-power per year. It was decided to substitute for the engines a motor-drive, of sufficient capacity to operate from the 900-ft. level, and ultimately install an entirely new hoist. After disconnecting the engines, installing a new shaft, and making a few minor changes, a 300-h-p., 2,300-volt, 514-rev. per min., variable-speed motor of the induction type was geared to the reel-shaft. The reels were supplied with 3/8 by 4-in. flat rope, and the duty of the hoist was about as follows: Cage, 1,700; ore, 2,600; car, 1,400; rope, 2,250; total, 7,950 pounds. The Bristol ammeter chart, Fig. 1, shows the combined current-consumption of the hoist- and mine-motors. The large intermittent load is clearly shown ; this produced harmful fluctuations in the voltage of the long, lightly-loaded, 60,000-volt transmission-line from Spokane to the Coeur d&apos;Alènes. The power company received no compensation for the increased cost of producing power for this intermittent or fluctuating load. In order to protect its system from similar excessive

Sep 1, 1912

Note by the Secretary.-—In the preceding communication of Mr. Rickard, in the present discussion, as printed in Trans., xxiii., the loss of quicksilver at Pestarena, reported on p. 569, as 230 and 234 grammes per metric ton, is stated as equivalent to about 74 pounds per short ton avoirdupois—an obvious error, which escaped correction in my reading of the proofs, and was not discovered until after Vol. XXIII. had left the press. The true equivalent is 0.46 pound or about 7 1/2 ounces (instead of pounds) per short ton.— R. w. R. Philip Argall, Denver, Colo. (communication to the Secretary) : Mr. Rickard&apos;s last contribution to this discussion* calls for some reply from me, if only by way of defending myself against the charge (p. 569) that my criticisms of his paper were "unnecessarily hypercritical and occasionally unfair." At the same time I am fully aware that our Transactions are not the place for mere personal controversy, and that the sole object of discussion is to define differences of opinion, and defend opposing views as a means of eliciting the truth. Mr. Rickard disclaims the statement, which he says I attributed to him, that in the slow-crushing Gilpin county mills the pyrites remain longer in the mortar than the other portions of the ore. My understanding of his statement was based on the following passages in his paper: " Particles of ore, which have heen pulverized to a fineness which would permit of their exit through the screen, are enabled to settle towards the bottom of the mortar. It would he expected that the heavy metallic minerals occurring in the ore would, because of their greater specific gravity, be most affected by this feature of the treatment. In practice this is found to be so. The fine slimes contain a large proportion of metallic sulphides, generally valuable on account of their close association with the precious metals, while the coarsest particles to be found in the tailings usually consist of quartz and other minerals forming the less heavy gangue (Trans., xxiii., 139).

Jan 1, 1895

By G. Sachs, A. W. Dana, C. C. Chow

A great number of the investigations on the plastic flow of metals have been concerned with the establishment of a "universal" stress-strain relation. In such a relation some stress function when plotted against a strain function should yield identical curves for the various stress states. In the first investigation of this type, Ludwik and Scheu1 plotted the maximum shearing stress as a function of the maximum principal strain. Later Ros and Eichinger2 introduced two universal stress-strain relations, the one relating the maximum shearing stress to the maximum shearing strain, and the other relating a stress invariant, suggested by von Mises and Haigh, to the corresponding strain invariant. (In more recent investigations the stress and strain invariants are frequently supplemented with some factor to render their meaning more lucid.) A further suggestion which has not attracted appreciable attention is that by Baranski³ who used stress and strain deviators. The most common means of experimentation to determine the relation between stress and strain consists in subjecting thin walled tubes to combined internal pressure and axial tension.4a,4b,4c This method allows the study of plastic flow under stresses which are variable in two directions. However, the plastic flow which can be obtained in this manner is comparatively small, being limited by either tension failure or instability. For copper,&apos;. only the relation between maximum shearing stress and maximum shearing strain yielded good agreement. On the other hand, tests on a stee14b and on an aluminum alloy4c. resulted in systematic deviations if any of the discussed universal stress-strain relations were used. It would seem, therefore, that the agreement mentioned above for copper is only incidental and explained by its high rate of strain hardening compared to that of other metals. Much larger strains than experienced in the tube tests can be obtained by subjecting a thin membrane of a ductile metal, which is restrained at its periphery, to a uniform hydraulic pressure. The thin sheet forms a deep bulge before it fails. The stresses and strains in such a bulge increase with increasing distance from the edge of the clamping "die," the maximum stresses and strains occurring at the pole (crown) of the bulge. While the stress and strain states are determined by the contour of the bulge, the absolute magnitude of the stresses and strains depends upon the hydraulic pressure. The bulge contour is in turn correlated with the geometry of the die opening. The deformation and fracture characteristics of circular bulges, that is, bulges formed with circular clamping dies, have been the subject of numerous experimental and analytical investi-gations.5,6,7 It has been shown that plastically deformed circular bulges develop large and comparatively uniform strains before failure by instability"6b,6c,6d and closely assume a spherical shape.6d Also the distribution of strains across the contour of the bulge is dependent on the metal being investigated and is correlated with, but cannot be predicted from, the metal&apos;s stress-strain characteristics. On the other hand, oblong or elliptical bulges, that is, bulges formed with elliptical clamping dies, are not as susceptible to analytical analysis and have not been investigated to the extent that circular bulges have. The few available data6c,7c indicate that stress states are obtained at the poles of the bulges, varying between plane strain and balanced biaxial tension, depending upon the geometry of the die opening. In this paper, the strain state and curvatures exhibited by three bulge shapes, a circular and two elliptical bulges, Fig 1, are analyzed experimentally using methods described in previous publications.6a,6c An attempt is made to derive the stress-strain relations for these bulges, which represent strain states in which the ratio of the two positive principal strains varied between 1.0 and 0.35. In addition, tension tests yielded data for a value of —0.5 for this strain ratio. Such an analysis should indicate the applicability of the various laws correlating stress with strain to the stress and strain states occurring in bulged shapes. Definitions and Nomenclature The definitions of the major stress and strain quantities used in this paper are as follows: s1, s2, s3 = principal normal stresses Sl > s2 > S3 t = shear stress e = conventional (unit) strain e = In (1 + e) El, E2, E3 = principal natural strains 7 = shear strain The maximum shear stress: , _ S1 — S3 lmax = 2 Frequently, the flow stress, s1 — s3 = 2lmax rather than the maximum shear stress is used.

Jan 1, 1950