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By J. W. Cunningham, M. J. Stultzman

THE demand for improved materials for high-temperature service has increased during the last few years. Iron,- nickel,- and cobalt-base alloys have been investigated extensively and many alloys with outs'tanding high-temperature strength have been developed. Considerable research has been directed toward improved methods of processing these alloys. The vacuum furnace as a tool for the purification and improved control of high-temperature alloys has been studied extensively and production units are in operation. The research covered by this paper studied the effects of casting in air, vacuum, or argon upon the elevated-temperature properties of two nickel- and two cobalt-base alloys. The alloys investigated were Stellite 31, He 1049, Udimet 500, and Guy Alloy. MELTING AND CASTING PROCEDURES Two heats of each of the four alloys under investigation were melted and investment cast under the following conditions: 1) Stellite 31 was melted and investment cast in air and in vacuum, with an argon atmosphere for pouring. 2) He 1049 was melted and investment cast in air and in vacuum, with an argon atmosphere for pouring. 3) Udimet 500 was melted and investment cast in vacuum with and without additions of zirconium and boron. 4) Guy Alloy was melted and investment cast in vacuum and in argon. The heats were all melted in induction furnaces equipped with preformed magnesia crucibles of 50-lb capacity. The air-melting furnace was powered by a spark-gap converter of 40 kw capacity. The vacuum-melting furnace was powered by a motor-generator set of 100 kw capacity. The argon heat of Guy alloy was melted in the vacuum melting furnace under an argon atmosphere. Virgin materials were used for preparing all heats except the air heats of Stellite 31 and He 1049. The charge for the air heat of Stellite 31 was a commercial blend of shot. The charge for the air heat of He 1049 was Stellite 6 shot plus those virgin materials necessary to give the desired composition. All of the materials used were of the same grade used com-

Jan 1, 1960

AALL, Christian H.,(M'49), Asst Res Dir Monsanto Chemical Co Anniston, Ala AALSETH, Earl P ,(J,51), Amerada Petr Corp Geological Dept Williston N Dak AAMOT, Olav Crone, (M'29), Met Pacific N W Alloys, Inc , Box 6215, Hillyard P 0 Spokane 14, Wash AARING, Floyd D ,(J'48), Petr Engr P 0 Box 130, Calgary, Alta Canada AARCNSON, Hubert Irving, (S'47), Carnegie Inst of Tech., Pittsburgh, Pa ABADIE, Henry G ,(M'43), Asst to the Sup- of Operations, Long Beach Oil Development Co ,255 So Santa Clara Ave Long Beach, Calif ABBISS, H. J., (A'50), Min. Engr., Buchans Mining Co., Ltd.. Buchans, Newfoundland ABBOTT, Clarence Eugene, (M'04), 901 Insurance Bldg , Raleigh, N C ABBOTT, George, (S'52), Mass Inst of Tech Cambridge, Mass

Jan 1, 1952

By Edward H. Robie

Jan 1, 1971

By James T. Wood

Stratigraphy, structure and closure of the Paloma field are discussed, with some details regarding the present state of development. The Paloma anticline, a large dome modified by faults, is the largest single closed dome in the southern San Joaquin valley without surface outcrop or topographic expression. It owes its discovery to geophysics. Of nine wells drilled to the Stevens sand, seven are productive. The ultimate productive area may approximate 3000 acres when the limits of the field are determined. Introduction The Paloma field derives its name from the Paloma school, ½ mile north of what is now the center of the field. The field is 17 miles southwest of Bakers-field, in the south central part of the San Joaquin Valley (Fig. I). The present developed area and its expected extensions are in townships 31 and 32S., R.26E. It is the most southerly of several fields that produce from the Stevens sand zone. The first well to produce condensate was a joint test drilled by the Western Gulf Oil Co. and The Texas Co. near the center of sec. 3, T.32S., R.26E., well No. 54-3. This well was completed on Aug. 31, 1939, at a depth of 10,178 ft. The initial production was 2280 bbl. a day of condensate and 14,750,000 cu. ft. of gas (½-hr. gauge) through a ?-in. bean. Prior to the drilling of this well, the Ohio Oil Co. discovered and developed a small gas field, which embraces a part of three townships about their common corner but lies chiefly in secs. 31 and 32, T.31S., R.26E. The first well was completed on July I, 1934, at a plugged depth of 5239 ft. after having been drilled to 7957 ft, production was found in a 59-ft. zone IIO ft. below the Fourth Mya bed, within the Sari Joaquin clays. Until recently this field was known as the Buena Vista gas field. It is now carried by the Division of Oil and Gas as the Paloma gas field. Production within the Paloma gas field is derived from six wells, producing from several different zones in the interval from 4177 to 5548 feet. Geology Stratigraphy The sediments penetrated by wells in the Paloma held range in age from Recent to Upper Miocene. The entire section, which exceeds 10,000 ft. in thickness, conforms generally to the standard section of the south central San Joaquin Valley. The producing zone, sometimes called the Paloma sand, is the approximate equivalent of the Stevens sand zone of the Ten Section, Canal, Coles Levee and other fields. The stratigraphic section is shown in Table I. Paloma Producing Zone* (Stevens Sand Zone, Upper Miocene) .-The Paloma producing zone (Fig. 2), frequently referred to as the Paloma sand, is encountered at depths ranging from 9950 to 10,300 ft. In general, it is a massive, firm to hard, not too well sorted, fine to medium fine sand. It is interbedded with thin, hard, calcareous sand shells of similar texture and cherty

Jan 1, 1942

By James T. Wood

Stratigraphy, structure and closure of the Paloma field are discussed, with some details regarding the present state of development. The Paloma anticline, a large dome modified by faults, is the largest single closed dome in the southern San Joaquin valley without surface outcrop or topographic expression. It owes its discovery to geophysics. Of nine wells drilled to the Stevens sand, seven are productive. The ultimate productive area may approximate 3000 acres when the limits of the field are determined. Introduction The Paloma field derives its name from the Paloma school, ½ mile north of what is now the center of the field. The field is 17 miles southwest of Bakers-field, in the south central part of the San Joaquin Valley (Fig. I). The present developed area and its expected extensions are in townships 31 and 32S., R.26E. It is the most southerly of several fields that produce from the Stevens sand zone. The first well to produce condensate was a joint test drilled by the Western Gulf Oil Co. and The Texas Co. near the center of sec. 3, T.32S., R.26E., well No. 54-3. This well was completed on Aug. 31, 1939, at a depth of 10,178 ft. The initial production was 2280 bbl. a day of condensate and 14,750,000 cu. ft. of gas (½-hr. gauge) through a ?-in. bean. Prior to the drilling of this well, the Ohio Oil Co. discovered and developed a small gas field, which embraces a part of three townships about their common corner but lies chiefly in secs. 31 and 32, T.31S., R.26E. The first well was completed on July I, 1934, at a plugged depth of 5239 ft. after having been drilled to 7957 ft, production was found in a 59-ft. zone IIO ft. below the Fourth Mya bed, within the Sari Joaquin clays. Until recently this field was known as the Buena Vista gas field. It is now carried by the Division of Oil and Gas as the Paloma gas field. Production within the Paloma gas field is derived from six wells, producing from several different zones in the interval from 4177 to 5548 feet. Geology Stratigraphy The sediments penetrated by wells in the Paloma held range in age from Recent to Upper Miocene. The entire section, which exceeds 10,000 ft. in thickness, conforms generally to the standard section of the south central San Joaquin Valley. The producing zone, sometimes called the Paloma sand, is the approximate equivalent of the Stevens sand zone of the Ten Section, Canal, Coles Levee and other fields. The stratigraphic section is shown in Table I. Paloma Producing Zone* (Stevens Sand Zone, Upper Miocene) .-The Paloma producing zone (Fig. 2), frequently referred to as the Paloma sand, is encountered at depths ranging from 9950 to 10,300 ft. In general, it is a massive, firm to hard, not too well sorted, fine to medium fine sand. It is interbedded with thin, hard, calcareous sand shells of similar texture and cherty

Jan 1, 1942

By Charles Dorrance

Culm is a general term used in the anthracite regions for many years to denote a mixture of coal, bony coal and impurities which is sent to the refuse-banks. Thus, 35 years ago culm contained the pea and buckwheat sizes of anthracite; but to-day, and as mentioned in this paper, culm is used specifically to denote the material which passes through the smallest screen in the anthracite-breaker. The smallest size of commercial anthracite is known as No. 3 buckwheat, barley, or bird's-eye coal, and is ordinarily made through a round-punched plate having openings & in. in diameter, and over a round-punched plate with openings 3/32 in. or 1/16 in. in diameter. Thus culm will consist of coal, bony coal, slate, gravel, iron pyrite, etc., ranging in size from 3/32 in. down to dust. Other local terms for culm are " slush," " silt," and " dirt." The first experiments towards the utilization of anthracite culm by briquetting, and the first briquetting-work done in this country, were in 1872 at Port Richmond Piers, Philadelphia, Pa., by E. F. Loiseau.1 Clay was used as a binder and the finished briquette was water-proofed with shellac, etc. Excessive cost was given as the reason for discontinuing work at this plant.

Jan 1, 1912

By William L. Fink, Dana W. Smith

In parts I1 and II2 of this series, there were presented results of investigations on the age-hardening of an aluminum-copper and an aluminum-magnesium alloy. It was shown that the simple precipitation theory of hardening3 adequately explained the aging phenomena, including certain so-called "anomalous" behaviors which had caused other investigators to reject or modify the precipitation theory. However, these papers did not discuss the double aging peaks, which have been stressed in recent articles by Dr. M. Cohen4 and Dr. M. L. V. Gayler.6 The present paper is devoted to an explanation of this "anomaly." Fig. 1 is a generalized schematic representation of aging curves at different temperatures. Curve A corresponds to the aging at the lowest temperature, and D at the highest temperature. Certain previous investigators have explained curve A and the initial peaks

Jan 1, 1938

By William L. Fink, Dana W. Smith

In parts I1 and II2 of this series, there were presented results of investigations on the age-hardening of an aluminum-copper and an aluminum-magnesium alloy. It was shown that the simple precipitation theory of hardening3 adequately explained the aging phenomena, including certain so-called "anomalous" behaviors which had caused other investigators to reject or modify the precipitation theory. However, these papers did not discuss the double aging peaks, which have been stressed in recent articles by Dr. M. Cohen4 and Dr. M. L. V. Gayler.6 The present paper is devoted to an explanation of this "anomaly." Fig. 1 is a generalized schematic representation of aging curves at different temperatures. Curve A corresponds to the aging at the lowest temperature, and D at the highest temperature. Certain previous investigators have explained curve A and the initial peaks

Jan 1, 1938

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 H. P. Croft

[ ] Professor Hibbard's paper presents a very interesting theory concerning the influence of texture on the tendency of brass tube to stress-corrosion crack. I should like to present the result of some work done in 1941 which may throw further light on the subject. In the first place, in regard to his review of the influences of grain boundaries, we not only confirmed the findings which he quoted, but also were unable to crack single crystals of beta brass in the standard mercurous nitrate test in 50 hr under loads up to 18,500 psi. Samples containing two or more crystals of beta brass always cracked at grain boundaries and generally followed the same pattern as for alpha brass, although cracking occurred sooner than in alpha brass under the same conditions. Such a specimen is shown in Fig 4. Second, at the possible risk of repetition, we should like to call attention to the reported role of grain size as influencing the tendency to stress-corrosion crack. This phenomenon, originally mentioned by Dr. Allan Morris in the Transactions, AIME, 1931, is illustrated in Fig 5, showing the effect of variations in grain size on the tendency of drawn brass wires to crack under load in the mercurous nitrate solution. This was taken from my work published in Proceedings A.S.T.M. 41, (1941), 905.

Jan 1, 1948

By John Griffen

HYDRAULIC classification as explained by Rittinger and others was largely restricted to conditions wherein the free-falling velocities of the particles were conceived as governing the separations effected (see chapter 9). The laws governing classification under free-falling conditions have been summarized by Chapman and Mott as follows:

Jan 1, 1943

By S. S. PRENZ

Discussion held at the sessions of the Canal Zone meeting, November, 1910. [SECRETARY'S NOTE.-As a result of this discussion, an expression of opinion covering all points of unanimous agreement was adopted and signed by members of the Institute party as individuals. This statement, which was printed in the Bulletin of December, 1910, is reprinted below, as an introduction to ,the detailed report of the discussion. It should be clearly understood that it does not constitute an official declaration by the Institute, the rules of which forbid any such action. At the New Haven meeting of February, 1909, a free discussion of the plan of the canal took place, in which the critics of the present scheme had full opportunity to state their views. That discussion was continued at considerable length in the newspapers ; but the Institute was never committed to either side. In this latter instance, the situation is precisely similar. Certain members and guests of the Institute, having had the advantage of later developments and of personal inspection, have expressed the conclusions at which they have arrived on their own responsibility ; and these conclusions are published by the Institute, subject to further discussion, like any other part of its proceedings. The general statement referred to contained a promise that the full discussion, of which it was a result, would be subsequently printed ; and this promise is fulfilled, so far as practicable, in the subjoined report, concerning which I beg to offer the following explanations: 1. It is made up of the remarks of the members of our party, as subsequently written out and mailed to the Secretary. 2. In editing these contributions, I have condensed the material considerably by cutting out much repetition of opinions and phrases ; and in such excision, I, frankly confess, the authors whose communications were delayed, have been the sufferers. Nevertheless, there is a good deal of repetition left, as there must be, when so many persons had talked so much, and come to agreement upon so many points. 3. It has been found impossible to preserve in this report the actual order of the free and informal oral discussion represented. Consequently the several contributions have been arranged in alphabetical order under the names of their authors. References to "preceding speakers," etc., must therefore be construed as referring to other speakers, preceding or following.-R. W. R.] S. S. PRINZ AUGUST WILHELM, AT SEA, November 14, 1910. We, the undersigned, members and guests of the American Institute of Mining Engineers, after a visit to the Isthmus of Panama, and inspection of the work of the United States Isthmian Canal Commission, and after full discussion of our individual impressions, find ourselves in unanimous agreement as to the following conclusions:

Jan 1, 1911

Aamot, Olav Crone, Chem. Engr., Norsk Elektrokemisk, Kongensgt. 18, Oslo, Norway. '29 Abbott, Clarence E., V.P., Charge of Raw Materials, Tennessee Coal, Iron & R. R. Co., 1242 Brown-Marx Bldg., Birmingham, Ala. '04 Abel, Raymond L., Prof., Dept. of Pet. Refin., Univ. of Pittsburgh ..Pittsburgh, Pa. '28 Abel, Walter D., Cons. Engr 364 S. Cloverdale Ave., Los Angeles, Calif. '32 Abele, Louis T R.F.D. 1, Adamsville, Ohio. '31 Abell, Leo M., Ore Dressing Investigator, School of Mines Adelaide, S. Australia. '31 Abenius, Hakan V., Mine Supt., Bolidens Gruvaktiebolag Boliden, Sweden. '37 Aborn, Robert H., Asst. Met., Research Lab., U. S. Steel Corp., Lincoln Highway, Kearny, N. J. '19 Abraham, W. E. V., East India United Service Club, 16 St. James' Sq., London, S.W. 1,, England. '28

Jan 1, 1937

By K. H. Heino

Two 200 T/da Lurgi Turbulent Layer fluid-bed roasters have been in operation at Canadian Electrolytic Zinc Limited since 1966. Zinc concentrate containing 52-54% Zn, 9-11% Fe,31-33% S is treated to produce calcine containing 60-62% Zn,10-12% Fe, .l-.3% S as sulphide and .8-1.2% S as sulphate. Each roaster train comprises a waste heat boiler, two cyclones in parallel and a two-field electrostatic precipitator. Distribution of calcine collected is 10-15 percent from bed overflow, 55-65 percent from boilers, 20-25 percent from cyclones and 2-6 percent from precipitators. A Monsanto designed contact plant produces acid at a rated capacity of 365 T/da (100% H2304 basis) from roaster gases diluted to 7.0-7.5% S02. The process steps are gas cleaning and cooling by weak acid scrubbing, acid mist removal in electrostatic precipitators, gas drying in 93.5-96.5% H2304, conversion of sulphur dioxide to sulphur trioxide in a four-pass converter containing vanadium pentoxide catalyst, and absorption of the sulphur trioxide in 98.1-98.3% H2S04. Product acid is 93.2% H2S04. Conversion efficiency is 97-98 percent and overall sulphur recovery from concentrate is 87-90 percent. The adjacent fertilizer plant has a capacity of 135 T/da of P205. The products are 54 percent phosphoric acid, run-of-pile triple superphosphate, and diammonium phosphate. The plant is of Ugine-Kuhlman design and consists of an air-cooled multiple tank reactor, a tilting pan filter, and a forced circultation vacuum evaporator. Triple superphosphate is made on a continuous belt and partially cured in a rotary dryer. Diammonium phosphate is produced by ammoniating phosphoric acid in a single stage reactor. The slurry of ammonium phosphate is granulated in a blunger and dried.

Jan 1, 1970

By Edward C. Jeffrey

The use of coke in metallurgy, to any important degree, dates from the middle of the 18th century. Its utilization came most opportunely for European civilization. The forests of Europe, except in the most remote and inaccessible regions, had been largely fed, in the form of charcoal, into the smelting furnaces. For a hundred years—the middle of the 17th to the middle of the 18th century—there .was a stationary condition of population corresponding to the exhaustion of European forests. This situation, which was particularly evident in Great Britain, was due to the fact that the forests had been depleted and the practical utilization of coke had not begun. The coking industry is essential for our metallurgical industries, which in turn are basal to healthy economic progress. But coke is of great importance, not only on its own account, but for its byproducts, which enter fundamentally into all the arts of peace and war. The dyestuff industry and the manufacture of explosives are intimately connected with one another, as was shown by the recent war. The subject of coking coal, therefore, is well worthy the serious attention both of practical industry and the scientific investigator. The most valuable coking coals, from the metallurgical standpoint, are derived from the coals of highest ranks. Coals, for example, that have a carbon ratio of from 70 to 80 per cent. yield the most valuable coke for the blast furnace. The difficulty of investigating these coals, however, is great, for they are rather friable and delicate and possess a high carbon content, which makes them difficult to manipulate. They present, on account of their high carbon content, a considerable degree of opacity when examined, in thin sections, under the microscope. The tenderness of structure and blackness of such high-grade coking coals as those of Connellsville and the Pocahontas region make them extremely difficult to investigate. Two of my colleagues, who are taking part in this discussion, will describe the valuable results that have been reached by studying coal by the methods of the mineralogist. Doctor White and Doctor Thiessen have studied the structure of coal as determined from thin sections that

Jan 1, 1925

By W. R. Crane

DRAINAGE in these mines has been discussed in papers, on mining practice,1 but the fact that water, varying from 0.16 to 3.46 and averaging 1.43 times the amount of ore mined, has to be pumped from the mines daily, indicates the importance of the problem and the advisability of making a thorough investigation of the source of mine water, its mode of entry into the mines, its effect upon mining conditions; and consideration of means of improving the conditions. While conditions are not serious, yet there is danger that they may become worse if present mining practice is continued, owing to the presence of formations, known to carry large quantities of water, that overlie the ore bed worked. Much detailed information has been collected regarding: rainfall, and run-off in streams draining the district; the effect of different kinds of formations, porous and non-porous; the inclination of the surface; the condition of the surface above the mines, i. e., whether or not disturbed by ground movement; the occurrence of the ore and character of associated formations, particularly with respect to presence of jointing or slip planes, faults, etc.; failure of top rock in the old stopes; and the conditions under which water effects entrance into the mines, i. e., whether as a natural or forced flow. The study furnished fundamental data on the source of waters now entering the mines and that which may later enter due to collapse of top formations in. abandoned workings. The presence of jointing, or slip planes, has a pronounced influence upon the whole drainage problem. These present lines of least resistance to the water and, by weakening the top formations, cause fracturing of the overlying rock, allowing both surface and deep-seated waters to enter the mines.

Jan 1, 1927

By K. A. Grange, W. S. Holt, E. T. Tkac

Quantitative knowledge of the time clement involved in austenite transformation in a particular steel provides a sound basis for understanding and planning heat-treatment. Such knowledge is conveniently obtained by measurement of austenite transformation as it occurs at each of a series of temperature levels. The results of these measurements usually are summarized in the form of the now familiar isothermal transformation diagram (I-T diagram, TTT diagram, or S-curve). Although a considerable number of such diagrams already have appeared in the literature, there remain many compositions of commercial importance for which no I-T diagram is available. The diagram for many such steels may be predicted from published data with sufficient accuracy for most practical purposes, but for others no satisfactory prediction can be made because the effect on austenite transformation of one or more of the important alloying elements present is not well enough known. Such a steel is Nitralloy, Type 13s-Modified, which, containing about 1.25 per cent aluminum, differs from any whose I-T diagram has been published. This paper presents results of a study of the isothermal transformation behavior of a sample from a commercial heat of this aluminum-chromium-molybdenum steel, together with pertinent supplementary data including the equilibrium transformation temperatures (Aeaand Ae,), the temperature range of martensite formation, and the end-quench harden-ability. These data are directly applicable to the hcat-treatment of this type of steel and are of interest in revealing some of the fundamental effects of aluminum as an alloying element in steel. Material All specimens were prepared from a 1 1/4 i-in. diam bar forged from a 5 by 5-in. billet from a commercial heat made in an electric arc furnace. The composition of the bar was; C, 0.41 per cent: AIn, 0.57: P, 0.016: S, 0.005: Si, 0.24: Ni, 0.17: Cr, I.j7: Mo, 0.36: All 1.26. The forged bar was normalized from r750°F (95s°C) and then tempered for one hour at rzoo°F (650°C), this tempering treatment having been given to facilitate the machining of specimens. Equilibrium Transformation Temperatures In hypoeutectoid steel the minimum temperature at which austenite is completely stable, Aep, and the maximum temperature at which austenite is completely unstable, Ael, are of great significance in heat-treatment. Since these temperatures are dependent upon com-

Jan 1, 1948

By W. S. Holt, K. A. Grange, E. T. Tkac

Quantitative knowledge of the time clement involved in austenite transformation in a particular steel provides a sound basis for understanding and planning heat-treatment. Such knowledge is conveniently obtained by measurement of austenite transformation as it occurs at each of a series of temperature levels. The results of these measurements usually are summarized in the form of the now familiar isothermal transformation diagram (I-T diagram, TTT diagram, or S-curve). Although a considerable number of such diagrams already have appeared in the literature, there remain many compositions of commercial importance for which no I-T diagram is available. The diagram for many such steels may be predicted from published data with sufficient accuracy for most practical purposes, but for others no satisfactory prediction can be made because the effect on austenite transformation of one or more of the important alloying elements present is not well enough known. Such a steel is Nitralloy, Type 13s-Modified, which, containing about 1.25 per cent aluminum, differs from any whose I-T diagram has been published. This paper presents results of a study of the isothermal transformation behavior of a sample from a commercial heat of this aluminum-chromium-molybdenum steel, together with pertinent supplementary data including the equilibrium transformation temperatures (Aeaand Ae,), the temperature range of martensite formation, and the end-quench harden-ability. These data are directly applicable to the hcat-treatment of this type of steel and are of interest in revealing some of the fundamental effects of aluminum as an alloying element in steel. Material All specimens were prepared from a 1 1/4 i-in. diam bar forged from a 5 by 5-in. billet from a commercial heat made in an electric arc furnace. The composition of the bar was; C, 0.41 per cent: AIn, 0.57: P, 0.016: S, 0.005: Si, 0.24: Ni, 0.17: Cr, I.j7: Mo, 0.36: All 1.26. The forged bar was normalized from r750°F (95s°C) and then tempered for one hour at rzoo°F (650°C), this tempering treatment having been given to facilitate the machining of specimens. Equilibrium Transformation Temperatures In hypoeutectoid steel the minimum temperature at which austenite is completely stable, Aep, and the maximum temperature at which austenite is completely unstable, Ael, are of great significance in heat-treatment. Since these temperatures are dependent upon com-

Jan 1, 1948

By AIME

IN the parlance of Hollywood, it was a super-colossal meeting. In the more restrained language of engineers, the Institute's 75th Anniversary Celebration attracted the largest crowd ever; was the longest Annual Meeting ever held, occupying a full week; had more important papers, more important people, more of an international flavor, and more glamour than ever before. And in the minds of those who came to the big city from the wide open spaces, one other record should be mentioned: for those not on an expense account, it was the most expensive affair ever staged by the Institute! To state the attendance down to the last digit for a meeting such as this is impossible. The total names registered on cards, plus those who attended the Annual Banquet but were not otherwise registered, came to 3149. But a few were registered twice, and probably a still larger few did not register at all, but just dropped in for a session or two in which they were interested. It would appear that 3200 would be about as close an estimate of attendance as could be made, and that is some 300 more than came to the biggest Annual Meeting of the past-in 1944. A considerable number of members brought their wives, but most were delegates at large.

Jan 1, 1947

By M. J. Pool, with Appendix by Larry Kaufman, R. W. Krenzer

Thermodynmic properties of the Cu-Mn system have been deterrrzined in the temperature range 973" to 1273°K by measuring the vapor pressure of manganese in equilibrium with alloys of compositions varying from 0.13 to 0.91 rnole fraction manganese using the Knudsen effusion technique. Activities of manganese calculated from the measured vapor pressures show large positive deviations. Calculated heats and entropies of mixing are positive with a maximum occurring at approximately 0. 7 mole fraction manganese. ThE investigation of thermodynamic properties of binary systems involving transition metals is of considerable interest at the present time. The incomplete subvalency electron levels of transition metals lead to unusual behavior in some alloys, and considerable information can be obtained by determining the thermodynamic characteristics of these systems and relating the thermodynamic behavior to observed physical properties. The Cu-Mn system, shown in Fig. 1,' provides an example of an alloy system in which the determination of the equilibrium phase diagram and various physical properties has received considerable attention, but very little work has been done on measurement of the thermodynamic properties. Elemental copper and manganese have comparable electronegatives, atomic sizes, and cohesive energies, but differ in crystal structure. They form a continuous series of solid solutions only at high temperatures and the structure varies in a continuous manner from fcc at the copper-rich end to fct at the manganese-rich end.' The purpose of this investigation was to measure the vapor pressure of manganese over a series of Cu-Mn alloys and from these values determine the thermodynamic properties of the binary system. Vapor pressure measurements were made in the temperature range 973" to 1273"K, remaining within the solid-solution region for each alloy studied. EXPERIMENTAL PROCEDURE The relative thermodynamic properties of solid Cu-Mn alloys were determined from vapor pressure measurements by means of the Knudsen effusion tech- nique. Several discussions of the theory can be found in the literature. In the case of copper and manganese, it is assumed that manganese is the only component subliming, so the vapor pressure of manganese over the various alloys can be determined directly by measuring the weight loss of the effusion cell. This is a valid assumption since the vapor pressure of manganese is about four orders of magnitude higher than the vapor pressure of copper in the temperature region of interest. The vapor pressure of manganese over the alloys at any given temperature is then related to the weight loss of the effusion cell per unit area per unit time. An upper limit of 1.5 x 10"s has been measured for the ratio of polyatomic to monoatomic molecules for manganese vapor in equilibrium with solid manganese at 1180°K, so it was assumed that manganese vapor is monoatomic. The effusion cells, fabricated from high-purity alumina, are 26 mm high, 18 mm OD, and have a wall thickness of 1 mm. Three different sized holes of 2.03, 2.54, and 3.18 mm diam were drilled in the lids from the inside face to minimize chipping, and the lids were then slip-cast onto the cells to provide a gas-tight seal. Alumina was selected for this particular application both because of its resistance to thermal shock and reaction with manganese vapor. In the ideal case, the orifice of the effusion cell should have a knife edge so that effusion through the orifice

Jan 1, 1970