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By Gordon MacVean

THE adoption of rock dusting, as a safety measure, has made notable progress in the West Virginia coal mines since May, 1925. At that time there were but two mines in the State that were thoroughly rock dusted, mines No. 2 and No. 12 of the Boone County Coal Corp., at Sharpless. Since then it is probable that 75 per cent of the coal operators in the State have given consideration at one time or another to rock dusting. This growth of interest followed the meetings of the various mining institutes all over the country, during the summer of 1925, at which papers were presented, drawing the attention of the coal mining operators to the merits of this safety measure. Yet outside of the experience with rock dusting at the Old Ben Coal Corp., of Southern Illinois, and the Carbon Fuel Co., of Rains, Utah, there had been no actual occurrence in the coal mines of the United States, which could be taken as positive evidence of the efficacy of rock dusting in the prevention of the propagation of coal dust explosions. The U. S. Bureau of Mines, however, had run innumerable tests under conditions which closely approximated actual coal mining conditions and had clearly shown that rock dusting was effective.

Jan 1, 1926

By Michael J. Messel

OF the various minerals that occur in fibrous form known as asbestos, chrysotile is the variety most in demand for commercial uses, and, last year, over 683,000 tons of the various grades were produced in Canada and United States, exclusive of African and Russian production, which figures are uncertain. Production has not been able to keep up with the increased demand, and an acute shortage exists. Canada, Russia, and Africa are still the most important producers. However, Russia consumes most of its production at home and exports very little. The United States consumes over 60 pct of the total production and produces only about 4 pct of the total from deposits in Vermont and small quantities from Arizona. This paper will review mainly, some of the more recent developments concerned with the extraction and processing of this fibrous mineral for various industrial uses, such as textiles, insulation, building materials and brake linings.

Jan 1, 1949

Jan 1, 1902

Page Laboratory Methods...........................127 Special Analytical Methods.......................127 Improvements in the Accuracy of the Vacuum-fusion Method for the Determination of Oxygen in Steel....................127 Quantitative Spectrochemical Analysis of Mixtures of Gases.......131 Oxygen Samples from Open-hearth Bath...............133 Rapid Analysis of Sample for Alumina.................139 Accurate Carbon Analyses in Low-carbon Steel.............139 Laboratory Technique for Study of Reactions Involving Liquid Metal. . . . 142 Rotating Liquid Crucibles......................143 Stationary Crucibles.........................145 Jones and Laughlin Experimental Furnace...............148 Vacuum Melting..........................149 Measurement of Temperature of Liquid Iron and Steel;..........149 Pouring and Teeming Temperatures..................149 Bath Temperatures.........................151 Plant Methods.............................154 Methods of Studying Slags.......................154 Sampling Slag in the Open Hearth..................155 Viscosity of Open-hearth Slags....................155 Petrographic Examination of Slag...................156 Statistical Methods Applied to Study and Control of Chemical Relations in Bath...............................166 Rapid Method of -Correlation Applicable to Study of Steelmaking Reactions............................166 INTRODUCTION On Thursday morning, Feb. 16, 1939, a round table discussion was held on the subject of Experimental Methods in the Study of Steelmaking. Dr. John Chipman, Professor of Metallurgy at the Massachusetts Institute of Technology, and chairman of the A.I.M.E. Committee on Physical Chemistry of Steelmaking, presided. In opening the meeting, the chairman said: "The purpose of this round table is to discuss methods of study by which more and better information on the fundamentals of steelmaking can be obtained. It was thought that a round table discussion rather than a symposium would furnish the best opportunity for those actually using various methods of study to get together and discuss their common problems. For this reason attention will be focused upon methods of study rather than upon their results. We want new and current and up-to-date discussion.

Jan 1, 1940

Page Laboratory Methods...........................127 Special Analytical Methods.......................127 Improvements in the Accuracy of the Vacuum-fusion Method for the Determination of Oxygen in Steel....................127 Quantitative Spectrochemical Analysis of Mixtures of Gases.......131 Oxygen Samples from Open-hearth Bath...............133 Rapid Analysis of Sample for Alumina.................139 Accurate Carbon Analyses in Low-carbon Steel.............139 Laboratory Technique for Study of Reactions Involving Liquid Metal. . . . 142 Rotating Liquid Crucibles......................143 Stationary Crucibles.........................145 Jones and Laughlin Experimental Furnace...............148 Vacuum Melting..........................149 Measurement of Temperature of Liquid Iron and Steel;..........149 Pouring and Teeming Temperatures..................149 Bath Temperatures.........................151 Plant Methods.............................154 Methods of Studying Slags.......................154 Sampling Slag in the Open Hearth..................155 Viscosity of Open-hearth Slags....................155 Petrographic Examination of Slag...................156 Statistical Methods Applied to Study and Control of Chemical Relations in Bath...............................166 Rapid Method of -Correlation Applicable to Study of Steelmaking Reactions............................166 INTRODUCTION On Thursday morning, Feb. 16, 1939, a round table discussion was held on the subject of Experimental Methods in the Study of Steelmaking. Dr. John Chipman, Professor of Metallurgy at the Massachusetts Institute of Technology, and chairman of the A.I.M.E. Committee on Physical Chemistry of Steelmaking, presided. In opening the meeting, the chairman said: "The purpose of this round table is to discuss methods of study by which more and better information on the fundamentals of steelmaking can be obtained. It was thought that a round table discussion rather than a symposium would furnish the best opportunity for those actually using various methods of study to get together and discuss their common problems. For this reason attention will be focused upon methods of study rather than upon their results. We want new and current and up-to-date discussion.

Jan 1, 1940

By J. C. Bradley

THE relation of annealing temperature to conductivity of copper wire has been determined.1 Conductivity hard was 98.26 per cent. After a 10-min. heating at 200° C. it was 98.69. By annealing 10 min. at 300° C. a large increase, to 100.93, occurred. Maximum conductivity, 101.15, was attained after a 500° C. anneal; thereafter it decreased to 100.53 after a 950° C. anneal. If copper is gassed the decrease is much more than this. MATERIAL AND METHOD The work was done on high grade electrolytic copper, 99.942 per cent. copper-plus silver, silver 0.0008 per cent. It was hot-rolled to 3 in., then cold drawn to 0.080 in. The wire was cut into 25 5-ft. lengths and numbered 1 to 25 as cut. Four samples were tested hard. The others were wound into 5-in. diameter coils. For the 100° C. heating a coil was put into water, the water brought to boiling, and the wire kept at this temperature for 10 min. For the higher temperatures the coils were placed in envelopes of sheet copper, a little water added, and the envelopes sealed by folding over the edges twice, and hammering them together. This kept the air out very well. The envelope and wire were brought to the desired temperature; this was maintained for 10 min., then the whole was water-quenched.

Jan 1, 1927

By F. W. Bradley

MY first Nevada City mining reminiscence is one of seeing Capt. Thomas Mein, over 52 years ago, in the old Wyoming mill on Deer Creek about a mile below the town of Nevada City. Captain Mein was then superintendent of the Wyoming mine, where the old fashioned Cornish pump was used, as well as hurdy-gurdy water wheels for power. This mill was one of the typical, up-to-date mills of that time and consisted of stamps, fed by Chinese hand feeders, who also cobbed the ore down to a small enough size to be fed into the mortars. Stamps at that time were of light weight and crushed about one ton to one and a half tons to the stamp, the pulp going over plates, then into sluices with self-raising gates. When a sluice became full the pulp was shut off and directed into the parallel sluice, also with a self-raising gate. The concentrate thus collected in the sluice was shoveled out and carried to Cornish buddles and there cleaned up, preparatory to being sent to a local custom chlorination works.

Jan 1, 1929

By John A. E. M. Church

THE prospector's pan was the first implement used for saving gold, and its action is so effective that it has never been equalled for thorough work. Copper plates, blankets, sluices, and amalgamators of several patented designs have thrust it aside, but in spite of all the advances made there is no dispute among experienced men as to the comparative thoroughness of the work done by it and its rivals. When its rivals are doing their best, the pan can take their discarded refuse and prove their inefficiency by producing from it not only gold, but even the mercury which has been lost from the machines themselves. The trouble with the pan has always been that it was only a tool. Man was the machine that moved it. His work was high-priced, the quantity treated small, and it was impossible to use the pan for any but the richest sands. As a consequence the best gold-saving appliance known has been discarded for years and replaced by machines of inferior excellence, but which could more than make up for their limited ability in saving gold by their capacity for treating great quantities of ore. Mr. Peck is one of the old-time amalgamators of the Comstock district, and the first idea of the new machine came to him as he used to pan below the tailrace of his mill. No matter how fine the work of the mill was, the pan invariably proved that better could be done. The tailings always contained gold, silver, and mercury. This state of things is just as true to-day, after all the improvements that have been made, as it was then, and the much-vaunted method of the " Washoe process" consists in extracting 72 per cent. of the gold and silver by one operation, and then repeating this operation half a dozen times to get out about one-third of the remainder. With all the advances of twenty years in milling, there is nothing more crude in metallurgy than the treatment of tailings in many of the large mills of the West.

Jan 1, 1880

By Norman P. Goss

The Chairman.—Thank YOU, Mr. Goss Gentlemen, I believe we have heard one of the finest papers, especially since Mr. Goss has been very generous in his frank discussion of continuous casting. One point he has brought out which 1 think some of us have not thought through to the same extent that he has—that the continuous casting process offers the small producer an opportunity to compete with the larger, more conventional and presumably better established industries. The meeting is now open for discussion. Are there any questions concerning the first two papers? J. A. Malone.*—I should like to ask Mr. Goss whether there is any special problem involved in the first part, the upper part of the mold before he gets to the first graphite lubricant area. N. P. Goss.—You mean in the forming chamber where chilling first takes place? J. A. Malone.—Yes. N. P. Goss.—So far I have not had any trouble in this part of the setup. My only

Jan 1, 1945

By J. G. Giddings, R. Kobayashi

Residual viscosity, the ViSCOSitY at a given pressure and temperature minus the dilute gas viscosity at the same temperature, has been found to be independent of temperature for pure components and mixtures for simple molecules and light hydrocarbons. The residual viscosities for methane, ethane, propane and four mixtures were correlated as a function of reduced density and molecular weight. INTRODUCTION Earlier efforts in correlating the viscosity of light hydrocarbons and associated gases under pressure, primarily by some form of the corresponding states principle, have been reported elsewhere.7 The formal theory of corresponding states principle for viscosity from non-equilibrium statistical mechanical arguments for simple molecules has been developed by Helfand and Rice.13 The most serious obstacle to the development of a generalized corresponding states representation of viscosity data, even for simple molecules, has been the limited quantity of precise viscosity data of pure components and mixtures over a wide range of pressure and temperature conditions. Viscosity data on light hydrocarbons have recently been contributed by several laboratories.2,6,8,23,25,26 In the study of the viscosity of nitrogen, Michels and Gibson" observed that the viscosities of nitrogen as a function of density gave parallel isotherms. The same behavior has since been reported for other gases.".= The observed behavior indicates that the residual viscosity or the viscosity at a given pressure and temperature minus the dilute gas viscosity at the same temperature is a unique function of the density. Abas-Zade,1 Michels and Botzen,18 and Michels, Bot-Zen, Friedman and Sengers,19 observed similar behavior for thermal conductivity, the residual thermal conductivity being defined in a manner parallel to that of residual viscosity. Thodos and co-workers 4,15,24 applied the residual viscosity concept to the viscosity of pure monatomic and diatomic gases. Ellington and co-workers10,25 made the residual viscosity vs density plots for ethane and propane, but omitted the region below a residual viscosity of 15 micropoise and showed a systematic separation of the ethane isotherms in the low density region. Eakin correlated the residual viscosity of methane, ethane, propane and n-butane empirically as a function of density and molecular weight: Carmichael and Sage6 recently presented ethane residual viscosity vs density values in the gaseous liquid, and near critical regions as a single univariant function of density. Flynn, Hanks, Lemaire and ROSS" have contributed extremely accurate viscosity data to confirm that the residual viscosity concept is essentially correct, but may not be accurate within 0.1 per cent of the viscosity value for the gaseous state- The recent studies by Giddings12 indicate that the residual viscosity of methane, propane and each of four methane-propane mixtures are unique functions of density Over the temperature and the density ranges studied.

Jan 1, 1965

By Odmund Ljone

FAR north of the Arctic Circle is a totally industrial community which until 1945 could not boast a single specimen of the rat family, and where today you will be awarded a bottle of fine cognac for every rat-dead or alive. Amazing but true, the spot is Longyear City, the Norwegian mining town on the arctic island of Spitzbergen. Perhaps you have also heard of the town built on soil that never thaws, where huge blocks of ice must be melted to fill the city's fresh water reservoirs, and where the Far North dictates a way of life all its own. Here, coal is king and men must work hard for their "black gold." Spitzbergen is a rough, tough piece of Norway, made up of a half dozen isolated islands between 74 and 81 degrees north latitude. Covering twice the area of Belgium, they are home to

Jan 1, 1948

By M. C. Dow

INTRODUCTION BELT conveyors generally are conceded to be the most economical method yet devised for the transportation of large quantities of bulk materials within plants. Belts are coming into greater use for transportation over long distances and are replacing other forms of long-haul conveyance. It is not the intent of the writer to comment on the design of belt conveyors, but to offer some suggestions for improvement in the operation of conveying belts, based on many years experience with belts in several stonecrushing plants. It is the contention of this writer that opportunities for improvement not fully realized by most operators exist in many plants and that a study of the individual conveyors can result in lower unit belt costs. GENERAL RELIABILITY It is the fool-proof nature and general reliability of the belt conveyor that is responsible for its neglect. Even when abused, a belt will carry large tonnages and last a long time, often outlasting the personnel responsible for its care. Some operators look upon the purchase of a new belt as an expensive outlay every so many years, rather than a constant and steady cost amounting in belt wear alone to several dollars every operating day. This belt wear for all conveyors in one stone-crushing plant known by the writer costs 1 1/2 cents per ton or $12 to $15 per hour, based on the present cost of belt replacements. The fact that these replacement costs are double those of prewar quality emphasizes the necessity of improving the conditions that make belts wear out. Some of those conditions are the responsibility of the conveyor designer, and if a serious original error has been made, this handicap cannot be overcome by the operator. If the belt is too narrow, too steep, or too fast for good loading, the operator finds that he has an inherently expensive belt. The other factors that decrease the life of a belt are more or less under his control. The two factors of most importance are the loading conditions and the alignment. Most of the cover wear and carcass cutting occurs at the loading point and if the alignment is not good under all conditions, edge wear or damage may result, Fig I. LOADING THE BELT It is difficult to load a belt in an ideal manner; that is, to flow the material on the moving belt at a steady rate, without impact, without turbulence, and with a velocity equal to and in the same direction as the belt. An inclined belt is especially difficult to load and particularly when its speed is over 300 or 350 fpm. Inclined conveyors require longer skirt plates to prevent spillage until the load settles. It does not seem reasonable to expect an inclined conveyor to carry the same load as a horizontal belt of the same width and speed, because of the difficulty in loading

Jan 1, 1947

By R. Ruka, E. A. Gulbransen

ONE of the interesting questions in the understanding of the reaction of iron with oxygen is the kinetics and the mechanism of the crystal structure changes occurring in the formation and breakdown of the oxide film. In a recent work' the electron diffraction method was applied to the study of the solid phase reactions occurring internally in the oxide film on iron above 570°C and under vacuum conditions. The higher oxides which form under oxidizing conditions are reduced internally by the diffusion of iron into the oxide leaving the bulk of the oxide FeO (wüstite). This paper will ask and consider three questions. These are: (1) What is the nature of the depressed transformation temperature for the Fe3O4 + Fe ? 4Fe0 reaction in very thin oxide films?; (2) What is the mechanism of the forward transformation of Fe3O4 to FeO at or near 570°C?; and (3) What is the nature and mechanism of the slow reverse transformation of FeO to Fe3O4 and Fe below 570°C?. The composition of the oxide as well as its electrical, magnetic, mechanical, and chemical properties depends upon the kinetics of these reactions. Literature Survey The composition of the oxide film on pure iron at temperatures up to 570°C has been studied extensively by the electron diffraction method. Nelson,' Jackson and Quarrell,3 and Gulbransen and Hick-man4 have shown that Fe3O4 and a-Fe2O8 are formed in the temperature range of 225" to 570°C, while y-Fe,O, is most likely formed below 225°C for long oxidation times. In very thin films FeO (wüstite) is found to form at temperatures as low as 400°C, and its existence depends essentially upon the extent of initial oxidation. FeO is not found in the formation of thick films below 570°C. On the other hand X-ray5 and micrographic8 studies show that Fe3O4 may exist as the main com-ponent in thick films up to 650°C, well above the equilibrium temperature for the reaction Fe3O4 + Fe ? 4FeO. The kinetics of the forward and reverse trans-formations of the reaction Fe3O4 + Fe ? 4FeO have not been studied in oxide films. However, analysis of the data of Gulbransen and Hickman4 on the heat-ing and cooling of iron oxide films of known thick-nesses in high vacua shows that the forward reac-tion proceeds rapidly even for a 4000 A film at temperatures of 575" to 600°C. The reverse reaction or decomposition of wüstite (FeO) occurs at tem-peratures below 450°C. Thus, there appears to be a slow process in the decomposition which is in marked contrast to the rapid forward reaction. The decomposition of a bulk sample of FeO free from the metal has been studied extensively by Chaudron, Benard and coworkers using the micro-graphic, X-ray diffraction, and thermomagnetic methods. Chaudron7,8 first observed that the de-composition of FeO (wüstite) below 570°C occurs by the reaction 4FeO ? Fe3O4 + Fe. Later work by Chaudron and Forestier5 showed that the rate of de-

Jan 1, 1951

By Homer Turner

THE nature and comparative features of anthracite and bituminous coals have been discussed by the writer in two previous papers.1 Although this paper is offered as a further contribution to the subject, it seems desirable at the outset to repeat some of the descriptive matter of the early works in order to show the actual connection between various constituents of both coals and the new photomicrographs and other physical and chemical properties.

Jan 1, 1929

By Earnest R. Woakes

Those engaged in pumping from shafts, or other mining works, may be intereited in the following suggestion of what is believed to be a novel method of raising moderate quantities of water against a considerable head. It is admitted that the ordinary Cornish pump, as generally used in mines, is hard to beat, on account of both its extreme simplicity and its easy adaptation to the requirements of mining; its great drawback, however, being the enormous weight of heavy rods and successive plungers that have to be kept in motion, not to mention the necessary " balance-" and " angle-bobs," with all their accompanying friction and wear and tear. It is contended that the following method would, to a great extent, overcome these drawbacks ; though, no doubt, many old miners may say it would also introduce new ones. Possibly, this may be the case. It is only desired that this pump may be judged upon its merits. The chief novelty of the method consists in employing the almost unlimited pressure obtainable from a high column of water, augmented, if necessary, by a hydraulic ram or press at the top, to work a small-diameter piston or plunger at the bottom of a shaft or well. This high-pressure plunger, indicated at E, in Fig. 1, transmits power direct to a larger-diameter plunger, F, constituting, together with the ordinary H-piece, valves, and wind-bore, the actual pump, which raises the water, by column C, to the adit-level or other discharge, placed as far as possible below the head of the high-pressure column A and ram W. It will thus be seen, that it is only necessary to maintain a prmsnre on the small piston, E, equal to that on the larger one, F, by means of the small but high column of water, A, in order to cause F to descend, and thus force the water up through C. The up-stroke is accomplished by a small water-wheel, or other engine, connected to the light rod or wire rope B, this having only to raise the weight of the actual plungers and fill the H-piece with water from the tank or

Jan 1, 1892

By M. J. Saarivirta

A high-purity copper-zirconium alloy system was imesti-gated. The zirconium content of the alloys studied varied from 0.003 to 0.23 pet. The solid solubility of zirconium in copper and some physical and mechanical properties of the alloys have been determined. By proper heat treatment, Cu-Zr alloy can develop a high electrical conductivity and resistance to softening at temperatures up to 500°C (930°F). This combination of desirable properties makes this alloy superior, to other com-merzcrrl copper base alloys for- use in the electrical conductor field. DEMAND for high conductivity copper alloys that retain their mechanical properties at elevated temperatures is growing rapidly. At present, copper-base alloys such as copper-silver and copper-chromium are used where these characteristics are required. As an example, commutators in electric motors are often made of these alloys. However, the life at elevated temperature of commutators made of copper-silver alloys is much shorter than the life of the same part made of copper-chromium and copper-zirconium alloys. Copper-silver alloys are subject to creep and subsequent failure when the service temperature exceeds several hundred degrees centigrade. Use of copper-chromium alloys has been known for the past several years, but little information is available in the literature concerning the properties of alloys in the copper-zirconium alloy system. Some work had been directed toward determining the solubility of zirconium in copper as well as determining properties of the Cu-Zr alloys. These investigations have revealed the superior high-temperature and electrical conductivity properties of copper-zirconium alloys over copper-chromium alloys. The United States Metals Refining Co., Carteret, N. J. has recently produced OFHC R copper-zirconium alloys for experimentation and evaluation. Because OFHC R copper contains no appreciable oxygen, no harmful oxides are formed and the full benefit of Zr as an alloying addition is obtained. This paper describes the results of this work. It contains room-temperature and some high-temperature data which have been obtained after various processing techniaues. Actual elevated temperature properties are being determined and will be reported in a separate paper. Preliminary results obtained at elevated temperatures suggest that the Cu-Zr alloy is superior to other high conductivity copper-base alloys. WORK PROCEDURE The high-purity oxygen free (OFHC R) copper-zirconium alloys with zirconium content ranging from 0.003 to 0.23 pct were cast into 4-by 4-in. wirebars by both continuous casting and conventional casting methods. Zr was added in the form of a master alloy containing 30 pct Zr and 70 pct Cu. Castings were analyzed for zirconium and nine bars containing various amounts of zirconium were selected for this study. The results of analyses and the sample numbers are given in Table I. Typical analyses of OFHC R copper are also shown. The following properties were studied: A) Solid solubility of zirconium in copper. B) Effect of zirconium on properties of copper. C) Effect of combined working and heat treating on properties of Cu-Zr alloys. The solid solubility of zirconium in copper was determined by metallographic techniques. Specimens for this phase of the investigation were hot rolled at 900oC (1650oF) to 0.250-in. rod. The rolled rods were cut into 2/3-in. long specimens and solution annealed at 950 °C (1740°F), 980°C (1795 °F). and 1020 °C (1870 °F) for 6 hr and quenched in water. In order to find the solid solubility limits at lower temperatures, the homogenized specimens were reheated at various temperatures for 1 hr and quenched. The physical and mechanical properties were determined on 0.250 in. rod, 0.132- and 0.081-in. wires. The wires were cold drawn from the 0.250-in. rods after they were solution annealed at 980 °C (1795°F) and quenched in cold water. Mechanical and electrical properties were determined on cold drawn and

Jan 1, 1961

By John A. Church

Jan 1, 1880

By L. H. Schwartz, S. K. Lahiri, M. E. Fine, D. Chandra

WHILE the yield stress of solution treated Fe-Cu alloys increases rapidly with aging, a precipitate has only been directly observed in overaged samples.'-" This precipitate is essentially pure fcc copper, the E phase. Hornbogen2 suggested that the initial hardening is due to clustering of copper atoms in a bcc iron matrix. Hornbogen was not able to obtain direct confirmation for such bcc clusters by either X-ray diffraction or electron microscopy; however, he did observe analogous clustering in Fe-Au alloys7 where the scattering factor difference between iron and gold is more favorable than that for iron and copper. Fujii, Nemoto, Suto, and Monma4 recently observed diffuse electron diffraction scattering in a 2.5 pct Cu alloy aged at 500°C: for 30 hr. They suggested that part of the diffuse SCattering was due to a modulated structure of 26 to 42 wavelength parallel to the (110) matrix plane. This disappeared with further aging. However, 30 hr at 500°C is well beyond the peak strengthening in this alloy which occurred at less than I hr at 500oc.4 By transmission electron microscopy they could not distinguish between quenched samples and samples aged to maximum strength. The purpose of the present investigation was to try to obtain further confirming evidence for a precipitation stage preceding the formation of the fcc E phase. Change in Young's modulus was selected for study be- EXPERIMENTAL PROCEDURE The Fe-1.67 at. pct Cu alloy was supplied by the U.S. Steel Corporation in the form of a hot forged rectangular bar. The carbon and nitrogen contents of this alloy were 70 ppm and less than 10 ppm, respectively. The samples for Young's modulus measurements were made by cold swaging to & in. diam and cutting to 2 in. lengths. Tensile test samples 1 in. long were prepared by cold rolling to a thickness of 0.012 in. and then machining to gage dimensions of 0.5 by 0.012 in. For Mijssbauer studies, foils 1 mil thick were prepared by cold rolling. During fabrication the alloy was given intermediate anneals at 845OC followed by quenching. The specimens after preparation were solution treated at 1000°C (y field) or 845°C (a field) for 1 to 2 and 5 to 6 hr, respectively, in a dynamic vacuum of about 2 x lom6 torr. The tensile and modulus specimens were drop-quenched into iced brine through an aluminum foil which vacuum-sealed the bottom of the furnace tube. The MOssbauer foils were drop-quenched into helium gas cooled by passing through N2 (liq) in a copper coil. The grain diameter of the modulus and tensile specimens was between 0.025 and 0.035 mm. The samples were aged from 400" to 500°C in a dynamic vacuum of 2 x 10-6 torr and cooled by pulling into a water-cooled portion of the vacuum system. The dynamic Young's modulus was measured at room temperature using electrostatic excitation and detection of longitudinal vibrations.' Neglecting any length change during the aging, (this is expected to be comparatively small), the fractional change of Young's modulus (?Et)/Eav, is equal to twice the fractional change of the resonant frequency (?ft)/fav . ?ft =ft —fo where fo and ft are the resonant frequencies of a specimen before aging and after aging to time t. The measured f's, approximately 51,000 cps, were corrected to 25°C for any variation in the ambient temperature. The tensile tests reported were carried out at room temperature in an Instron with a 1000 lb full scale load cell. The flow stress reported herein corresponds to a strain of 0.002. The Massbauer spectra were taken in a constant acceleration model AM-1 NSEC spectrometer. The

Jan 1, 1970

[A Aall, Christian H., M49 D Mgr, American Metal Climax, Inc., 61 Broadway, New York 6, N.Y. Aaroe, S. L., A54 B Sales Mgr, The W. S. Tyler Co. of Can. Ltd., St. Catharines, Ont., Canada Abalos, Teodulo Q., J57 A Foreman, Lepanto Cons. Ming. Co., Mt. Province, Philippines Abbass, G., M55 P. O. Box 680, Hong Kong, China . Abbitt, James M., A54 770 Sole Blvd., Bartow, Fla. Abdullah, M. Y., J53 Dept. of Mines Res. Div., P. O. Box 1016, Tiger Lane, Ipoh Perak, Malaya Able, John F., Jr., J53 A Ming Engr, USA SIPRE 1215 Washington Ave., Wilmette, Ill. Abell, Leo M., M31 B Conct Supt, Phelps Dodge Corp., Morenci, Ariz. Abenius, Hakan Wilhelm, M52 A Mng Dir, Stora Kopparbergs Bergslags AB, Falun, Sweden Abenoroth, Harry F., A57 Natl. Carbon India Ltd., 18A Brabourne Rd., Box 217, Calcutta, India Abercrombie, Harry W., J56 1645 Camphor Dr., Lakeland, Fla.]

Jan 1, 1961

By V. N. Krivobok

THE study and use of low-carbon manganese steels have been curiously neglected in the general history of developments in alloy steels. Hadfield1 made an extensive study of manganese-iron-carbon alloys about 1886, which culminated in the wide application and use of Hadfield austenitic manganese steel. His alloys were nearly all high in carbon, as compared with the steels discussed in this paper, and he found a marked tendency towards brittleness in the alloys of medium and low manganese content, that is, below 7 per cent. manganese. As a result, there has been a widespread prejudice against the use of manganese steels containing between 1.0 to 3.5 per cent. manganese with comparatively low carbon. Steels of this composition have never been studied adequately in comparison with other alloy steels, and have had little use in practice. In a very recent paper by Sir Robert Hadfield2 the following statement appears: ?. . . manganese-iron alloys with little or no carbon do not seem to offer any practical employment; they only become valuable in the presence of quite high percentages of carbon, 0.90 to 1.50 per cent." The results of the present investigation are so contrary to the findings of Hadfield that the writers feel fully justified in presenting the preliminary report incorporated in this paper.

Jan 1, 1927