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FOLLOWING the presentation of the papers by Messrs. Mahan and Butler, the discussion printed below ensued. A. C. LANE* With particular reference to the New England con-sumer, I entirely agree with Mr. Mahan that intelli-gent marketing methods will do a good deal, but there is more than one way of improving them. For instance, coal can be shipped best to New England about this time of year-after the storms of the winter and before the movement of crops in the summer. For that reason there ought to be seasonal freight rates. This will be agreed to by most coal men if you will ask them, especially those who are connected with large concerns like the Metropolitan Coal Co., and yet they do not get seasonal freight rates partly because the railroads are afraid if they once reduce them they will never have a chance to get them back again. But it would be an improvement to have seasonal freight rates. Another thing: When we are buying in New England we want really a certain amount of heat value in our coal. There is no great advantage in our buying ash, nor is there any particular advantage in the railroad shipping ash and clogging the circulatory system of the body politic any more than clogging the circulatory system of the physical body. It would be desirable if the wholesaler, and to some extent the retailer, could guarantee the amount of ash or sell their coal on heating value. If you are interested in that you will find some interesting charts, in "Anthracite Coal Costs Analyzed," a pamphlet issued by the Anthracite Coal Consumers Association, Inc., New York City, as to rates from various and sundry points for bituminous and anthra-cite coal from the field to New York, Buffalo and Chi-cago. Here in New England they are both up against the competition of oil. About 3 or 3 1/2 bbl. oil will do the work of a ton of coal. One of my millionaire friends who is well posted on the situation is putting oil in his Commonwealth Avenue house because it is the most economical. Moreover, we can get Welsh coal from across the water (and help equalize this matter of exchange with Europe) in close competition with Penn-sylvania coal.

Jan 4, 1928

By W. R. Hansen, F. W. Boulger

Twenty-nine laboratory steels were studied to determine the effects of composition and ferrite grain size on drop-weight and Charpy V-notch transition temperatures. The experimental steels covered the following ranges in composition.. 0.10 to 0.32 pct C, 0.30 to 1.31 pct Mn, 0.02 to 0.43 pct Si, md nil to 0.136 pct acid-soluble Al. Although most of the data were obtained on hot-rolled samples, some plates were heat-treated in order to cover a wider range in ferrite grain size. The experimental data were used for a multiple-correlation analysis conducted with the aid of an electronic computer. The study showed that carbon raises and that manganese, silicon, aluminum, and finer ferrite grains lower both drop-weight and Charpy transition temperatures. Quantitatively, variations in composition and grain size have a more marked effect on V15 Charpy transition temperatures than on the drop-weight transition temperature. Useful correlations were found between transition temperatures in drop-weight tests and those defined by seven different criteria for Charpy tests. Evidence was accumulated that the conditions ordinarily used for drop-weight tests are more severe for 1-1/4-in. -thick plate than for 5/8- to 1-in. -thickplate. PROJECT SR-151, to study quantitatively the effects of metallurgical variables on performance in the drop-weight test, was established by the Ship Structure Committee late in 1958 on recommendation of the National Academy of Sciences, National Research Council. This project was initiated as a result of the increasing use of the drop-weight (nil-ductility) test in predicting the ductile-to-brittle behavior of steel. Qualitative data indicated the drop-weight was not as sensitive to metallurgical variables as the Charpy V-notch test. Furthermore, the available information indicated that the drop-weight test did not show the superiority of killed steels over semikilled steels reflected by Charpy tests. This difference in sensitivity to brittle fracture is considered important because the drop-weight transition temperature has been reported1 to correlate better with service-temperature failures than the V-notch test does at a constant energy level. Therefore, this project was concerned with establishing quantitatively the effects of metallurgical variables in the drop-weight test. For comparison, Charpy V-notch data were obtained for the steels investigated. This paper summarizes the results of the investigation. Most of the steels used for the study were made and processed in the laboratory. However, some tests were also made on commercial killed steels available from Project SR-139 (SSC-141). During the course of the investigation, data were obtained on the effects of carbon, silicon, manganese, and aluminum on transition temperatures of drop-weight and Charpy specimens. In addition, the effects of heat treatment which changed the ferrite grain size and the transition temperatures were also investigated. Finally a few exploratory studies were made on commercial killed steels to evaluate the effects of plate thickness, grain size, and heat treatment on the performance of drop-weight specimens. EXPERIMENTAL PROCEDURES Preparation of Materials. A total of twenty-nine 500-lb induction-furnace heats were made and processed in the laboratory for the investigation. Carbon, manganese, silicon, and aluminum contents were systematically varied. Melting and rolling techniques proven satisfactory in a previous project2 were used as a guide for the current investigation. Composition. The composition of the twenty-nine laboratory heats made for this project are given in Table I. The steels are divided into three groups. The first group consists of ten aluminum-killed steels similar in composition to Class C ship-plate steel. The second group consists of ten semikilled or Class B type steels. In both of these groups the carbon and manganese contents were intentionally varied over a wide range. This wide range in composition was helpful in obtaining quantitative data from a limited number of steels. The primary purposes of these two groups of steels was to determine the effects of carbon, manganese, and deoxidation practice. In addition, one steel in each group (Steels 2-2 and 9-2) were made about 1 year after the start of the program in order to check consistency of melting practice. The third group of nine steels listed in Table I was intended for studies on the effects of silicon and aluminum. In eight of these steels carbon and manganese were held relatively constant at levels of about 0.2 and 0.8 pct, respectively, while silicon and

Jan 1, 1963

By M. B. Bever, A. M. Reti, A. K. Jena

The results of this investigation show that in the system SnTe-PbTe l) the solid solutions have small exothermic heats of formation relative to the binary compounds, 2) solid-solution hardening is almost absent, 3) the tin and lead atoms are .randomly distributed on the sublattice occupied by them and do not undergo an ordering transition during a thermal treatment designed to promote such a transition, and 4) the lattice parameter changes linearly with composition. These findings suggest that the solid solutions of tin telluride and lead telluride approach ideal behavior. THE binary compounds SnTe and PbTe form a continuous series of solid solutions.' Information on several physical properties of these solid-solution alloys has been published.1"3 In the work reported here, the heats of formation, microhardness, and lattice parameters of these alloys have been measured and the possibility of an order-disorder transition has been investigated. Order-disorder transitions occur in some solid solutions of binary compounds. In the system Bi2Te3-BizSes, for example, the electropositive bismuth atoms and the electronegative tellurium and selenium atoms always occupy separate layers. In the disordered alloy Bi2Te2Se, the tellurium and selenium atoms are randomly distributed on the layers occupied by them, while in the ordered alloy they occupy distinct layers.4 The NaC1-type (Bl) structure of SnTe-PbTe alloys consists of two sublattices, one of which is occupied by the electropositive tin and lead atoms and the other by the electronegative tellurium atoms; any ordering would be expected to occur in the sublattice occupied by the tin and lead atoms. PREPARATION OF SPECIMENS Polycrystalline specimens of PbTe and Sn1-xPbxTe (x = 0.25, 0.50, and 0.75) were prepared by melting stoichiometric amounts of lead (99.999 pct), tin (99.98 pct), and tellurium (99.999 pct) in evacuated and sealed Vycor tubes. Because of the deviation of tin telluride from the stoichiometric composition5 this compound was prepared by melting 49.8 at. pct Sn and 50.2 pct Te. The tubes containing the melts were quenched into water; the solidified ingots were removed from the tubes and annealed for 2 weeks in vacuum (PbTe approximately 100°C below its melting point, the three alloys 100°C below their solidus tem-

Jan 1, 1969

By J. G. Paterson, J. A. Meech

Abstract-Activated carbon is a strong adsorbent for amyl xanthate, capable of removing from solution up to a quarter of its own weight in xanthate. In selective flotation systems where depression is unstable, separation efficiency increases with activated carbon additions. The improvements observed are brought about by two mechanisms. First, by removing stripped and residual collector ions from solution, competition between depressant and xanthate is reduced and depression is stabilized. In addition, the texture of the froth phase at high pine oil concentrations is modified by activated carbon such that better drainage between the air bubbles takes place, alleviating the mechanical entrapment of depressed mineral particles. In treating a bulk copper/lead concentrate produced from GECO ore, selectively between galena and chalcopyrite is increased when activated carbon is used. Although the rate of flotation of galena is marginally lowered by activated carbon, a small extension in the duration of flotation allows the lead recovery to increase by 19% at the same recovery of copper. An addition rate of 0.75 kg/ton (1.5 lb/st) of bulk concentrate is suggested as optimum from this testwork. However, the actual level wed in the mill is dependent upon the residual concentrations of collector and frother in the bulk concentrate Pulp.

Jan 11, 1978

By Freeman Bishop

The tight electric power supply is one of the most dramatic problems facing the mining industry in 1971. This is caused by rising demands for energy. Clean-fuel and air-pollution controls have contributed to the problems of producing energy from sulfur oil and coal. Coking coal has become scarce. One stimulating development is that coal is no longer the cinder in the mining industry's eye. In fact, it may be the favorite candidate as a base for fuel within a few years. Synthetic gas from coal is the watchword. In dedicating a multi-million- dollar project aimed at converting coal into oil and gas, Hollis M. Dole, Assistant Secretary of the Interior, recently made it clear that coal, which has been taking a back seat to nuclear fission research and study grants, is now coming into its own. Conversion pilot plants are being activated in all parts of the nation.

Jan 1, 1970

Jan 1, 1947

Jan 1, 1947

By R. C. Buehl, M. B. Royer

High manganese slags of low phosphorus and iron content are produced by air oxidation of high phosphorus spiegeleisen in a basic-lined converter. Control of phosphorus and iron within specification limits for ferromanganese ore feed is obtained by a unique cyclic operating procedure. Various types of slags, or synthetic manganese ore, can be made. AN affiliated paper' describes the production of high phosphorus spiegeleisen containing 14 to 23 pct Mn and up to 4 pct P in an experimental blast furnace from open-hearth slag or manganiferous iron ore. This phosphorus content is too high for use of the spiegel in normal steel-production operations. Consequently, a preferential separation must be effected whereby the manganese is concentrated in a product that is usable in industrial operations. The preferential separation methods being investigated for this phase of the work are confined to pyrometal-lurgical processes for ready incorporation into steel-plant operations. It is fortunate that manganese is more actively oxidizable than iron or phosphorus, and therein lies a preferential separation method for isolating manganese from these two elements. Silicon is more strongly oxidizable than manganese, and its oxidation precedes, or occurs simultaneously, with manganese. Therefore, manganese and silicon are separable into a high manganese oxide slag phase while the phosphorus and iron remain in the molten metallic state. Complete separation of these elements represents an ideal condition which is not generally attainable in actual operations. This pyro-metallurgical method for separating manganese from phosphorus and iron by preferential oxidation was investigated by blowing 500 lb of metal in a basic-lined vessel to obtain preliminary information on the effectiveness of the procedure. Certain conditions of attainment in the separation process are desirable in any method for removing manganese from high phosphorus spiegeleisen, such as: 1—High recovery of manganese in the oxidation product; 2—the product to be of equal or better quality than ferromanganese-grade ore—48 pct Mn minimum, less than 10 pct SiO2, and Mn-P ratio of 300:1; and 3—attainment of the enumerated objectives in a product amenable to industrial handling, such as a slag of high manganese content that will flow from the processing vessel and of sufficient fluidity for ready separation of metallic granules that may have become mixed with the manganese slag phase. Previous Work Recovery of manganese from low grade ores and industrial byproduct slags by smelting to spiegeleisen, with subsequent oxidation to synthetic ferro-manganese-feed ores, has been a subject for periodic investigation during the past four or five decades in the United States and Germany. Joseph' and associates of the Bureau of Mines North Central Experiment Station, Minneapolis, Minn., smelted manganiferous iron ores of the Cuyuna range, Minn., to spiegeleisen and subsequently tried air and ore oxidation procedures for concentrating the manganese into synthetic ferrograde manganese ore. Joseph's results on the operation of a side-blown basic-lined converter for air oxidation of manganese from molten spiegeleisen were so discouraging that the procedure was abandoned after 11 blowing tests. Much slag was thrown from the converter vessel; phosphorus content was four to five times the maximum allowable for ferro ore; and a manganese-iron ratio of only 2 or 3:1 was obtained in the slag instead of the required 8:1. Oxidation of manganese from spiegeleisen with about 0.5 pct P, by adding iron ore to molten spiegel in an experimental open-hearth furnace, proved moderately successful in Joseph's experiments. The main drawback to the operation was the necessity for over-oreing for effective oxidation of the manganese with consequent too high iron oxide residual in the slag. Furthermore, the phosphorus content was proportional to the iron concentration and therefore much too high, so that several hours of reduction by a carbonaceous material were required to adjust the iron and phosphorus to the desired content of high grade ferro feed. A troublesome feature of the slag product of the spiegel oxidation process was its lack of fluidity if the silica content was less than 10 pct, the concentration considered desirable for the synthetic ore. Approximately twice the desired concentration of silica was required to impart enough fluidity for transfer from the vessel by pouring. The acute shortage of manganese in Germany

Jan 1, 1953

By J. Charles Miller

THE expansion of facilities for rapid transportation of perishables by train, truck and airplane has necessitated consideration of refrigerants of a minimum weight and volume per pound of cooling and has stimulated the use of solid carbon dioxide commercially. The gas probably has not had wide application in the past in air-cooling equipment for mines, theaters or buildings, owing to its thermodynamic properties, as will be deduced from examination of Table 2. However, consumption of the liquid in carbonating beverages remains a dominant factor. In addition to these uses, carbon dioxide is employed to a limited degree as an explo-sive in the liquid form, as a freezing agent in plumbing, in laboratories for low-temperature work, and in the manufacture of golf balls.

Jan 1, 1936

By B. Trentini

In the spectacular development of pure oxygen steel-making, the process using the vertical lance converter LD, is at the present time the most widely employed. Proper control of slag composition during the steel-making process appears to be essential in achieving satisfactory blowing from both the metallic yield and metallurgical points of view. The paper illustrates the primary importance of the presence of a large quantity of metal droplets in the slag during the process. In the case of both phosphorus and hematite pig iron, it can be deduced from the phase diagrams and confirmed by experimentation that nonhomogeneous slags are one of the causes of slag overflowing during the blow. The problem is however a complex one and further physicochemical studies appear necessary. Finally, the new continuous steelmakingprocess developed by IRSID is described. PEOPLE who knew Henri Marion Howe have said that he took great pleasure in speculating on the future of metallurgical processes. It is therefore not inappropriate to devote, in his memory, some description and discussion to processes unknown to the world of his time, in particular oxygen steelmaking and continuous steelmaking. The first industrial application to steelmaking of tonnage oxygen produced by air liquefaction was made in Germany just before the war and consisted in enriching the air blown through the bottom of a basic Begsemer converter in order to melt a higher proportion of scrap and to produce steels with lower nitrogen content than is achieved with conventional practice. While this process was being developed after the war, mostly in Western Europe, steelmakers were becoming increasingly familiar with the technique of blowing pure oxygen from the top, first by means of consumable steel pipes, with or without refractory shielding, and later by water-cooled lances, designed for the purpose and affording longer life. The field was then open for the wide use of pure oxygen in steelmaking, either in existing processes such as open-hearth or electric furnace, or in new processes. These new processes can be broadly classified according to the category of furnace employed. In the case of the vertical converter taken as the first category, bottom-blowing of pure oxygen causes extremely rapid wear of the refractory tuyeres, and although various expedients have been tried to overcome this drawback (such as mixing oxygen with CO2 or H2O or using high pressure oxygen), they have had to be abandoned. The solution for vertical converters has been found in top-blowing with a vertical water-cooled lance; this is known as the LD process or basic oxygen converter process.

Jan 1, 1969

GEO. F. COMSTOCK,* Niagara Falls, N. Y. (written discussion?).-In this exposition of experimental data, the author infers, indirectly at least, that by the Charpy test information was obtained that led to the improve-ment of certain ordnance parts and that this improvement could not have been attained without the Charpy test. On examination of the data, however, it appears that the important point of the whole matter was that while the material had been accepted from the results of longitudinal tensile tests, it was really transverse ductility that was desired. The writer has no desire to attempt to detract from the value of the paper or to discredit the Charpy test in any way, but he would like to ask the author if he will not give more clearly his reasons for preferring the Charpy impact test for investigational and control work of this kind, over the more usual tensile test made in a transverse direction. The tensile test pieces are more cheaply made than the square notched impact bars; and from the former the limit of elasticity and the ultimate strength as well as, the ductility are obtained, while in the Charpy test only one property is measured. It does not seem that the author has shown a sufficient reason for favoring the latter test, when both it and the trans-verse tensile test served his purpose equally well in indicating the proper metal and treatment required for his special forging, and it is hoped that this reason will be given more clearly as a matter of useful general information.

Jan 11, 1919

THE fifth annual convention of coal-operating men, with the usual exposition of coal-mine equipment, was held at Cincinnati, May 7 to 11 inclusive, and was fully up to the high standard set by previous years. This spring meeting has come to be one of the most helpful services to industry performed by the Ameri-can Mining Congress and a center at which operators and engineers easily and quickly get into touch with the newest and best things in practice and equipment. Over 200 exhibitors showed this year and very little if anything that is new `failed to be shown. The ex-hibits were well arranged and adequate rather than elaborate. They attracted the careful attention of the members and guests of the Congress, admission being by badge rather than by ticket sold to, the general public. Eight sessions were held for reading and dis-cussion of technical papers, one for Management and

Jan 6, 1928

By John A. Meech, J. G. Paterson

Activated carbon is a strong adsorbent for amyl xanthate, capable of removing from solution up to a quarter of its own weight in xanthate. In selective flotation system where depression is unstable, separation efficiency increases with activated carbon additions. The improvements observed are brought about by two mechanisms. First, by removing stripped and residual collector ions from solution, competition between depressant and xanthate is reduced and depression is stabilized. In addition, the texture of the froth phase at high pine oil concentrations is modified by activated carbon such that better drainage between the air bubbles takes place, alleviating the mechanical entrapment of depressed mineral particles. In treating a bulk copper/lead concentrate produced from GECO ore, selectively between galena and chalcopyrite is increased when activated carbon is used. Although the rate of flotation of galena is marginally lowered by activated carbon, a small extension in the duration of flotation allows the lead recovery to increase by 19% at the same recovery of copper. An addition rate of 0.75 kg/ton (1.5 lb/st) of bulk concentrate is suggested as optimum from this testwork. However, the actual level used in the mill is dependent upon the residual concentrations of collector and frother in the bulk concentrate pulp.

Jan 1, 1979

By J. A. Herrick

Jan 1, 1879

By James E. McNulty

Coal reserve estimates are prepared using a simple equation: the product of area, bed thickness, density and recovery factors. Each of these elements involves a degree of risk based on certain assumptions. Reserve area, thickness and density rely on certain physical data whose accuracy, reliability and sufficiency may be problematical. Estimates of recovery factors for mining and coal preparation are often subjective. Most reserve estimates assume, sometimes incorrectly, that the subject reserves will be completely extracted. The principle that certain coal resources are reserves, if they can be considered economically recoverable at the time of determination, needs to be reexamined in the light of recent market cycles. Reserve estimating requires the exercise of judgments, the validity of which reflect the qualifications, experience and objectivity of the estimator.

Jan 1, 1985

ON July 2 the Krupp plant in Essen was occupied by the French. The City of Frankfurt, on the edge of the Mayence Bridgehead was surrounded by the French. French infantry and cavalry occupied some more towns in the Ruhr. These moves were apparently in the way of reprisals. The Bank of England on July 5 raised its discount rate from three per cent. to four, per, cent., the lower rate having previously prevailed for almost exactly a year.. The advance appears to have been inspired by the reserve ratio, but especially owing to the fact that the low rate in the London market had led to the out-flow of funds from there to other markets. Philip Snowden brought up again in the British .Parliament his motion in favor of the condemnation of the capitalistic system and the substitution of socialism. The motion was put to vote and was defeated by large majority, only the members of the Labor party voting for it. The Allies and the Turks finally came to an agree-ment at Lausanne, the Turks getting about all for which they asked. It would be tiresome to record the details. The main fact is that the Turks, after having been ejected from Europe in 1918, are now going to return. Russia agreed to the settlement respecting the Straits. The Soviet Government of Russia formulated and adopted, subject to ratification, a constitution for the United States of Russia, which appears to be patterned after the constitution of the United States of America and the unwritten constitution of Great Britain. The important thing about this seems to be that it definitely reunites the constituent parts of the old Empire, the semi-independence of the Ukraine being surrendered.

Jan 7, 1923

By Norman P. Goss

It is generally agreed that cold-working mechanically refines the grains into smaller fragments and with continued working these are oriented with certain crystallographic directions bearing a relation to the direction in which the metal is worked. Some of the energy expended on the metal during plastic deformation appears in the form of heat, but a very small portion remains in the metal as stored energy. The entropy, specific heat capacity, temperature at which recrystallization will just begin, density, ductility, elasticity, tensile strength, and resistance to corrosion are affected. These properties have been studied extensively and some of the changes in the physical properties due to cold-working were attributed to lattice distortion.l-8 The broadening of the Ka lines on the X-ray diffraction diagrams of plastically deformed metals is believed to indicate lattice distortion, and consequently the existence of internal stresses. The evidence supporting this theory rests solely upon the observed experimental fact that the diffraction lines are broadened and the Ka doublets are completely diffused. Elam9 has reviewed the matter of lattice distortion in relationship to the hardening of metals by plastic deformation. The X-ray diagrams of plastically deformed metals differ in general from annealed metals. The hardening of a metal was believed due to lattice distortion.9 The resolution of the doublet is lost when a metal is cold-worked and the Laue spots are elongated. At one time this elongation was thought to indicate the elastic bending of the crystal planes. However, more careful work showed that the asterism was due to new orientations developed within the fragmented grains during plastic deformation. Some theories attributed the hardening to fragmentation of the grains into smaller units. Jeffries and Archer,ll after carefully considering the problem of work-hardening from many angles, came to the conclusion that cold-working mechanically refines the grains into smaller crystal fragments, some of which at least differ in orientation from the parent grain. The increase in

Jan 1, 1940

By Norman P. Goss

It is generally agreed that cold-working mechanically refines the grains into smaller fragments and with continued working these are oriented with certain crystallographic directions bearing a relation to the direction in which the metal is worked. Some of the energy expended on the metal during plastic deformation appears in the form of heat, but a very small portion remains in the metal as stored energy. The entropy, specific heat capacity, temperature at which recrystallization will just begin, density, ductility, elasticity, tensile strength, and resistance to corrosion are affected. These properties have been studied extensively and some of the changes in the physical properties due to cold-working were attributed to lattice distortion.l-8 The broadening of the Ka lines on the X-ray diffraction diagrams of plastically deformed metals is believed to indicate lattice distortion, and consequently the existence of internal stresses. The evidence supporting this theory rests solely upon the observed experimental fact that the diffraction lines are broadened and the Ka doublets are completely diffused. Elam9 has reviewed the matter of lattice distortion in relationship to the hardening of metals by plastic deformation. The X-ray diagrams of plastically deformed metals differ in general from annealed metals. The hardening of a metal was believed due to lattice distortion.9 The resolution of the doublet is lost when a metal is cold-worked and the Laue spots are elongated. At one time this elongation was thought to indicate the elastic bending of the crystal planes. However, more careful work showed that the asterism was due to new orientations developed within the fragmented grains during plastic deformation. Some theories attributed the hardening to fragmentation of the grains into smaller units. Jeffries and Archer,ll after carefully considering the problem of work-hardening from many angles, came to the conclusion that cold-working mechanically refines the grains into smaller crystal fragments, some of which at least differ in orientation from the parent grain. The increase in

Jan 1, 1940

Discussion of the paper of W. R. SHIMER, presented at the New York meeting, February, 1915, and printed in Bulletin No. 99, March, 1915, pp. 557 to. 585. WILLIAM R. WEBSTER, Philadelphia, Pa.-I would like to ask Mr. Shimer how the finishing temperature of the H-beams and other beams rolled on the Gray mill at Bethlehem compare with the rolling temperatures of the rails referred to in this paper. Also, how the reductions in the rolling of the beams compare with the reductions in the rolling of the rails. I would also like to know if any drop tests were' made on the rails referred to as having been allowed to cool and then annealed; in other words, what results, if any, were obtained from tests on rails after the internal strains of rolling had been removed; and in the matter of the rail blooms, I would like to ask if they are not often heated to a higher temperature than is desirable on account of the thin flanges in order to carry the heat through to the finishing pass. The tensile strength of the steel in these rails is given as 125,000 lb. per square inch, which is almost as high as tire steel. If some of these blooms were rolled into rounds of about the same section as the head of the rail, would you not get better results from tension tests than those from the head of the rail? In other words, in rolling rounds, whether you would not be able to control the rolling and finishing temperatures better than is possible in the rail, owing to thin section of the rail flanges. Some years ago I had experience with the rolling temperatures of tire steel, running from about 127,000 to 133,000 tensile strength. These tires had the tensile strength and the deflection specified. One of the manufacturers had no trouble whatever, after a little experimenting, in meeting the conditions of the specification. Another manufacturer who made some of these tires came to the office and stated that he had tried tires from three heats of steel and could not meet the specifications and

Jan 5, 1915

By J. H. Westbrook, R. W. Guard

The influence of a number of alloying additions on the structure and hardness of Ni3Al (?') has been studied. Three general effects have been observed.. solid-solution hardening, strain aging, and defect hardening arising from deviations from stoichiometry. The solid-solution hardening phenomena are complicated relative to binary terminal solid solutions due to the possibility of virtually independent substitution for the component elements and to the concomitant effects of strain aging. In many superior nickel-base high-temperature alloys the elevated temperature strength is attributable to the presence of a dispersion of Ni3A1 (?') in a solid-solution matrix. Examples of such alloys are Inconel X-550, Inco 713, Waspalloy, and Nimonic 80. It is, therefore, appropriate to seek a further understanding of the properties and alloying behavior of this compound. Ni3Al, the compound most rich in nickel in the nickel-aluminum binary system, was first detected by litakal but not established with certainty until the much later studies of Bradley and Taylor' and Alexander and Vaughan.3 More recently the mechanism of formation was clarified by Floyd4 who showed that Ni3Al is the product of a peritectic reaction at 1395°C between the melt and the compound NiAl in agreement with the original suggestion of Alexander and Vaughan.3 Ni3Al has the ordered face-centered-cubic or Cu3Au structure in which the nickel atoms occupy the face centers and the aluminum atoms the cube corners, a0 = 3.570A. Despite earlier reports to the contrary. the compound apparently remains ordered at least to 1000oC.5 It exists over a narrow range of compositions (-3 pct wide) whose limits and temperature dependencies thereof have been reviewed recently by Taylor and Floyd.' Most previous workers have found Ni3Al to be both hard and brittle7,8 although Maxwell and Grala8 obtained 2.5 to 6 pct tensile elongation at room temperature and Alexander and vaughan3 described the material as "hard and tough" on the basis of observations made while preparing metallographic specimens. In a recent study one of the present authors found that although considerable intergranu-lar brittleness was evident: individual grains of a coarse-grained inert atmosphere arc-melted specimen were readily deformable.l0 The same study also showed Ni3Al to have an anomalous temperature dependence of hardness in that such a curve exhibits a number of peaks between room temperature and 800°C which could not be associated with any microscopically observable precipitation reactions or polymorphic transformations. It was, therefore, proposed in the present study to elucidate the anomalous high-temperature strength behavior and to examine the solid-solution alloying of this compound and the effects of such alloying on hardness. Sample Preparation and Experimental Procedure-Samples, both of pure Ni,Al and of various alloyed solid solutions based on Ni3Al, were prepared by arc melting 100-g buttons in an inert atmosphere arc furnace. All buttons were heat treated for 4 hr at 1275oC and examined metallographically for homogeneity. Microstructures were typically homogeneous and single phase with ASTM grain size about 1 and unusually clean grain boundaries. Chemical analyses showed good correspondence (within a few tenths of a percent) with intended compositions. Microindentation hardness data were obtained from room temperature to 800°C in vacuo using a balanced-beam type loading system in an instrument to be described in detail elsewhere." In general a 100-g load, a loading rate of 1 mm per min and an indentation time of 15 sec were used. Various indenter materials were used according to the materials bein tested because of specimen-indenter interaction. Fl Measurements of the Vickers-type indentations were made at room temperature. Hardness-temperature curves were run at least twice on each sample to ensure that surface work-hardening effects had been eliminated." Precision lattice-parameter measurements were made on powder samples using a back-reflection

Jan 1, 1960