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By Jack G. Gill, Richard A. Dick

Blasting safety is a subject that cannot be overemphasized. Two years ago, a study was published describing g a series of fatal blasting accidents which took the lives of ten metal and nonmetal miners during the period of May 1973 to August 1974.1 Each accident was described, and the direct causes were delineated. In each instance, specific MESA safety regulations were violated. Four of the victims were killed by drilling into explosives; two were killed by lingering too long in the vicinity of fuse rounds; two fatalities resulted from improper guarding of shots; one blaster did not retreat far enough to avoid the blast concussion; and another used an improper tester for checking an electric blasting cap. All of these fatalities could have been avoided by adhering to the MESA blasting regulations contained in 30 CFR Part 55 (Health and Safety Standards-Metal and Nonmetallic Open-Pit Mines), Part 56 (Health and Safety Standards-Sand, Gravel and Crushed Stone Operations), and Part 57 (Health and Safety Standards-Metal and Nonmetallic Underground Mines).

Jan 11, 1977

By Rana P. Singh

Electrolytic metal reduction operatios in both aqueous and molten salt electrolytes are being studied by digital signal analysis. The purpose is to determine the relationship between the physical processes occurring in the cell and the frequency spectrum of the cell's fluctuating electrical parameters. The fast Fourier transform of cell voltage (in galvanostatic operations) or cell current (in potentiostatic operations) is computed on-line in real time for the electrorefining of zinc in aqueous acid chloride solutions.

Jan 1, 1984

By F. Keller, E. H. Dix, L. A. Willey

The consideration of alloying elements for aluminum has led to a series of investigations of the equilibrium relations between aluminum and those alloying elements. Therefore, the aluminum end of the aluminum-antimony diagram has been studied. The general form of the aluminum-antimony equilibrium diagram has been worked out by Campbell and Mathewsi and by Tammann.2 Canlpbell and mathews described principally the beginning of solidification. They found the curve of beginning of solidification rising gradually from the melting point of pure alunlinum to a maximum at about 67 per cent. aluminum. After a slight lowering of the curve at a little greater antimony concentration the curve again rises to a maximum at 18.4 per cent. aluminum, which corresponds to the compound AISb. The curve then drops to the melting point of pure antimony. Tamrriarln explained the maximum occurring at about 67 per cent. aluminum as the result of the slow formation of the single compound AISb. The space lattice of the compound AISb, according to Owen and Preaton,³ is face-centered cubic, the antimony atoms being intermeshed with an identical aluminum lattice. Very little, if any, work has been done on aluminum alloys containing small amounts of antimony. The Present Investigation It has been the purpose of this investigation to determine the solid solubility of antimony in aluminum and also to investigate the eutectic temperature and concentration. The experimental work has been carried out in a manner similar to that described in a previous paper4 from this laboratory.

Jan 1, 1931

By Ray W. Ballmer

"For his leadership in developing and managing large, complex, and technically innovative mines, particularly the outstanding and successful Bougainville mine and for his lecture, 'The Moving Targets of Mine Development '. " Recipient of the 1981 D. C. Jackling Award

Jan 1, 1982

By W. W. Wen, S. C. Sun

The objective of this investigation was to study the electrokinetic behavior of oxidized coals to indicate the feasibility of separating oxidized coals from ash materials and pyrite by an amine flotation process. The effects of soluble inorganic electrolyte products from coal oxidation were also examined. The electro-kinetic behavior of coals of different rank and degree of oxidation were studied by an electro-phoreses technique. Generally, increasing the oxidation increases the negative value of the zeta-potential and decreases the isoelectric point (IEP). Flotation results indicate that the flotation recovery increases with decreasing pH values, and that with ferrous sulfate at pH 6.5 the flotation recovery is optimum while the pyrite is depressed. Comparing the flotation results with the electokinetic results verified that in the presence of ferrous sulfate, the maximum hydro-phobicity of oxidized coal with dodecylamine and frother is near its IEP, which is around pH 6.5 to 7.0.

Jan 1, 1978

By Nicholas J. Grant, W. Michael Yim

The creep-rupture properties of nickel, in as-prestrained or prestrain-polygonized condition, were studied at 1300°F and 4000 psi, and also at 700°F and 26,000 psi. An improvement of strength was noted in both the as -prestrained and the prestrain-polygonized tests at each temperature. The as-prestrained tests, however, showed superior creep resistance to the prestrain-polygonized ones. From the results of X-ray and etch-pit studies, the strengthc gain was interpreted in terms of dislocation density and the stability of preformed substructures. COLD work is known to improve the strength properties of metals at low temperatures. At high temperatures, however, the strength improvement is often lost if gross structural changes, such as re-crystallization, take place prior to or during the test. Even in the absence of recrystallization, a prestrained metal may undergo structural changes— polygonization and the formation of well-defined subgrains—which importantly effect the resultant properties. The relationship between substructure and creep properties has received considerable attention in recent years. The work of wood1 indicated that the creep strength of aluminum and its alloys was closely related to the subgrain size. Hazlett and Hansen,2 and Ancker, Hazlett, and parker,3 working with nickel and nickel alloys, had shown that small amounts of prestrain at room temperature followed by a recovery anneal at 800°C (1470°F) improved the strength at both low and high temperatures. The strength gain was attributed to an increase in the number of subgrain boundaries as a result of the prestrain-polygonization treatment. More recently Coldren and Freeman4 studied the effect of substructures on the creep rate of nickel at 1550°F. Their conclusions indicated that the substructure size as measured by the number of boundaries was the factor that controlled the creep rate. In addition, the perfection of the subgrain boundary has been indicated to have an important role on the strength.' On the other hand, there are data which disagree with the above observations. Grant, Chaudhuri, Silver, and Ganow6 found no creep strength improvement by a prestraining treatment. In reviewing the role of subgrains on high-temperature creep, Shepard and Dorn7 concluded that the contribution of the subgrains to high-temperature creep strength was a minor one. Guard,8 in a recent study on poly-gonized nickel, has cast doubt on the validity of the postulate that subgrain size controls the creep rate. In the majority of the previous studies, the subgrain boundaries have been singled out as the most important factor in determining creep strength; however, there is no firm theoretical ground for the postulate that the subgrain boundaries act as effective barriers to dislocation motion.B910 Little effort has been directed toward the study of the relationship between creep strength and other structural variables, such as dislocation density, lattice strain,

Jan 1, 1963

By Claus Goetzel

THE object of this investigation was to determine whether silver alloys could be used instead of the currently employed insert of high-expansion AVERAGE COEFFICIENT PER DE G. C. OVEN RANGE 20° To 200° C. Pure aluminum '31.6 X 10-6 Cast low-expansion Si-Cu-Ni-Al piston alloy 20.0 X 10-6 High-expansion austenitic Cu-Ni cast iron 19.3 X 10-6 Cast steel (0.25-0.35 C, 0.10-1.0 Mn) 12.6 X 10-6 Cast iron (3.15 total C, 2.16 Si) 12.8 X 10-6 Pure silver 18.9 X 10-6 austenitic ferronickel alloy, to reduce the wear of ring grooves in light metal pistons. A typical example of a piston containing a ferronickel insert is shown in Fig. 1. The high coefficient of expansion of silver made it worthy of consideration, while the small size of the insert would render it use feasible in Germany as an emergency in is- tire. The coefficients of linear expansion of several metals and alloys are as shown in the table above. Obviously the melting point of the insert must be high enough to prevent it from melting when the light alloy is cast around it. This imposes a lower limit of about 850° C. for the solidus of the silver alloy. Pure silver melts at about 961° C., so that the Fin. 1.-PISTON CONTAINING tolerable depression in the solidus is rather FERRONICKEL INSERT. small. To avoid deformation of the insert during use a Brinell hardness number of at least 60 appears necessary.

Jan 1, 1937

September 1 to 6, 1918 COMMITTEE IN CHARGE Spencer Penrose, Chairman. George M. Taylor, Vice-Chairman. A. E. Carlton, Chairman. Finance Committee J. Dawson Hawkins, Secretary DENVER COLORADO SPRINGS CRIPPLE CREEK Finance Finance Thomas B. Crowe T. B. Stearns A. E. Canton , E. P. Arthur, Jr. Richard A. Parker Spencer Penrose N. S. Greensfelder T. B. Burbridge George M. Taylor A. E. Carlton. A. L. Blomfield, Treasurer B. F. Hill Arrangement I F. G. Willis Dave G. Miller Registration Norris E. Eads Frank Bulkley Loren C. Lennox 1V. E. Ryan Geo. E. Collins Horace F. Lunt Fred Jones .1. M. Tippett F. D. Smale Entertainment J. H. Haynes F. H. Bostwick Arrangement and Entertainment L. W. Lennox F. E. Shepard George M. Taylor A. L. Blomfield M. R.. Valentine Howland Bancroft J. D. Hawkins Thomas B. Crowe B. P. Morse A. E. Carlton E. P. Arthur J. G. Perry G. H. Clevenger Etienne A. Ritter Ladies Ladies , PUEBLO Mrs. T. B. Stearns, Mrs. C. M. Taylor, Mrs. C. H. Clevenger J. F. Welborn Chairman. Chairman H. B. Carpenter Mrs. C. Loughridge Mrs. S.-Penrose Mrs. A. E. Carlton L. B. Eames Mrs. H. Bancroft Mrs. J. D. Hawkins Mrs. A. L. Blomfield F. Robinson Mrs. G. Bancroft Mrs. L. C. Lennox Mrs. J. M. Tippett . Mrs. W. D. Leonard Mrs. H. F. Lunt -Mrs. E. C. van Diest Mrs. C. Chase Mrs. E. A. Ritter Mrs. AV. Strieby Mrs. F. H. Bostwick Mrs. L. S. Harner Mrs. C. L. Bailey Mrs. F. Bulkley Miss F. Dickerman Mrs. E. P. Shove Mrs. C. L. Tutt Mrs. F. C. Peck Mrs. F. D. Pastorius

Jan 10, 1918

"With a total value to date of well over $200,000,000.00 for its ore production, the Tintic mining district, which is about 100 miles southwest of Salt Lake City, ranks as one of the three main ore producing areas of Utah. In it are located the biggest silver mines of the country, silver having been the chief metal produced in the camp since its start. Tintic's silver production to date has a total value of over $ 100,000,000, approximately half of the value of the camp's ore production, the balance being roughly divided among lead, gold and copper.Discovery of the camp was made in the late sixties. Lack of transportation and ore reduction facilities delayed extensive development of the area for nearly a decade.In recent years Tintic's ore production has ranged from 350,000 to 400,000 tons annually. In 1 924 the camp produced one-eighth of the silver produced in the nation with an output of 7,729,700 ounces. Its lead production was 77,765,000 pounds and its gold production 26,285 ounces.The known mineralized area of the district is found in a broad syncline striking north and south. The west limb plunges sharply and extends for a distance on its dip of approximately one and a half miles to the trough. The east limb raises gently through a distance of about two miles to the east limit of known mineralization. This general structure is broken by local faulting throughout the district, the local structural conditions playing an important part in the ore deposition. The north end of the fold is obscured by a rhyolite flow and the south end stops against a monzonite stock."

Jan 1, 1925

By Eugene Stephenson

CRITICAL analyses of the work expended in producing oil by the utilization of gas energy have appeared in the publications of Shaw,1 Pierce and Lewis,2 and Herold,3 authors who have ably discussed the factors which must be taken into consideration in comparing energy consumed per barrel in various wells which are flowed by means of gas-lift. However, two distinct phases of oil production are concerned with the ratio of gas energy consumed to oil produced. One of these phases is the gas-lift, which utilizes the differential gas pressures for the purpose of flowing oil, whether these pressures be natural reservoir pressures or be induced by artificial compression of gas or air. The other phase has to do with prorating oil production in pools which are operated either as units, or are subject to such restrictions as those imposed at Oklahoma City by the Corporation Commission, or, by similar controlling groups in other fields. An abundance of literature is available relative to the problems of flowing wells by gas-lift, but the first suggestion that the energy of the gas within the oil and gas pool might serve as a basis for proration, appeared in the timely article by McWilliams.4 Much of the. dissatisfaction with proration in certain fields is because some operators feel that besides the hazard to the wells which accompanies the test, the method of allocating production on the basis of the "potential" gage is inequitable and gives some operators a distinct advantage over others.5 The most severe penalty may be exacted from the most progressive operators or those who attempt to produce their oil with a minimum quantity of reservoir gas. If :no difficulties ever

Jan 1, 1931

Fred. T. Greene, Rossland, B. C. (communication to the Secretary): At the beginning of his gaper, Mr. Herzig refers to an article of mine in the Engineering and Mining Journal of January 27, 1900. I would like to add that the method de-

Jan 1, 1901

In the four articles presented on the following pages, a panel of comminution experts offer readers the benefit of their experience with autogenous grinding and forecast some of the future developments to be expected in this fast-growing field. The articles are based on an AIME panel discussion in which the authors participated.

Jan 1, 1970

By G. R. Love, M. L. Picklesirner

THE use of color adds a new beauty, power, and versatility to metallography. This has been amply demonstrated in a number of public exhibits and on the walls of corporate, government, and university metallographic laboratories around the world. Indeed, in a number of cases, the color not only is of esthetic value but is scientifically essential to the competent examination of particular samples and systems. Optical strain analysis,' determination of true grain size in U-A1 alloys: phase identification in Nb-base alloys,3 analysis of transformation rates in heat-treated Nb-Zr alloys,4 measurement of solidification segregation in cast Nb-Zr alloys,' study of the intermediate phases in Nb/Sn diffusion couples,6 investigation of the oxidation kinetics at various surface orientations in single crystals,7'8 and a number of other research efforts9'10 would have been vastly more difficult without the extra clarity and distinction introduced by color—either the colors resulting from particular polarized light techniques or the interference colors obtained by oxidation. It is unfortunate that the beauty of colored micro-structures cannot be shared more widely, but the economics of publishing a technical magazine apparently prohibits color plates except under extraordinary circumstances. It is doubly unfortunate that no convenient, general method exists for communicating the information available in colored microstructures to the scientific community. True, in some instances the color changes observed are dramatic enough that direct black and white photography is adequate. In photoelastic stress analysis, several orders of interference fringes may be produced and it is frequently desirable to suppress the color effects (use monochromatic light) to simplify interpretation. On the other hand, relatively minute color variations may be readily detectable by eye, be of considerable assistance in interpreting a structure, and yet be enormously difficult to reduce to an unambiguous black and white print. In order to illustrate a possible compromise or solution to the above problems, we wish to show three black and white photographs of the same region of an Nb/Sn diffusion couple whose interpretation depends heavily upon use of color techniques. These micro-structures were obtained from a section through a rod consisting of commercial-purity niobium tubing filled with 99.995 pct Sn (melt-filled in 10"6 Torr vacuum). The composite rod, measuring 500 mm long, was bent into a hairpin shape and inserted into water-cooled copper grips in a vacuum high-temperature furnace. The rod was outgassed for 2 hr at a furnace temperature of 800°C and was further heated by self-resistance using a 2.2-kva ac power supply. The rod was raised to 1910°C over a 4+-hr period, held for 15 min, slow-cooled to 1500°C over a -hr period, and free-cooled to room temperature (all temperatures were measured with W5Re/W26Re thermocouple). Throughout the heat treatment the ambient pressure was kept below 8 x lo-' Torr. Metallographic preparation of the sample was completely conventional except that it was necessary to extend the grinding steps to remove damage in the brittle NbsSn phase introduced by sectioning. No satisfactory chemical or electrochemical etch has been found for these diffusion couples; of those which have been tried, any that attack the niobium-rich phases at all attack the tin-rich phases disastrously. However, the final polishing steps did produce a slight relief effect and this, coupled with anodizing, yielded excellent clarity in the microstructures for direct observation. The anodizing voltage was chosen to give maximum change in color per unit change in composition. In this case, indeed normally, this maximum sensitivity occurred in the blue-to-red color range. The pure niobium tube wall anodized to a relatively bright blue

Jan 1, 1967

By Steve H. Carpenter, Henry E. Otto

The explosive welding of metals is dependent upon the production of a jetting action caused by the collapsing of one metal plate against another. Successful welds are generally accomplished if the yield strength of the metals is in the range of 10,000 to 90,000 psi and the sonic velocity of the metal is greater than the detonation velocity of the explosive if direct contact explosive is being used.' Should the detonation velocity exceed the velocity of sound in the metal it may still be possible to obtain the jetting action and a good weld. However, in most cases where a high detonation velocity is used complications arise because of reflected shock waves which tear the bond apart as fast as it is put together.' Explosive welding of lead presents several problems since its yield strength and sound velocity are very low. Various values have been published3-5 for the velocity of sound in lead ranging from 2000~ to 23004 m per sec. Most of the high-order explosives have detonation velocities on the order of 6000 to 8000 m per sec, which precludes their use. The dynamites have a lower detonation velocity of around 2800 m per sec which is still somewhat too high. Lower-order explosives such as ammonium nitrate (1070 m per sec) must be used to weld lead in the as-received condition if the explosives are used in direct contact. Rather than use low-order explo'sives it was decided to alter the sonic velocity of the lead. The sonic velocity is directly related to the modulus of the material according to the following expression: Fig 1—Interface of explosive weld of lead to steel. Lead is on top As-polished Magnification 75 times as well as the yield strength. Bolling et al. 6 show that the shear modulus of lead single crystals increases from about 0.72 X1011 dynes per sq cm at 300°K to about 0.98 X1011 dynes per sq cm at 0°K, an increase of approximately 3 5 pct. This gives an increase in the sonic velocity of around 700 m per sec. Hence, the sonic velocity of lead at cryogenic temperatures is approximately equivalent to the detonation velocity of the low-order dynamites. We have obtained high-quality lead to steel explosive welds using a 40 pct dynamite in direct contact with the lead. Prior to detonation the lead was chilled with liquid nitrogen (78°K) to increase the strength and sonic velocity. Welds were made while the lead was cold. Specimen sizes were 3 by 6 in. A preset angle of 5 deg with a 0.10-in. standoff at the base was the geometrical setup used. The amount of explosive used for optimum welding of an 1/8 -in. -thick lead sheet to a steel plate was found to be 7 g per sq in. A PETN sheet explosive line wave generator was used to insure a linear detonation front through the dynamite. A photomicrograph of a lead-steel weld is shown in Fig. 1. The typical wave effect that constitutes a good explosive weld is present. When tested in shear, the weld failed in the lead, indicating that the bond is stronger than the lead base metal. Higher-order explosives were also tried without success. We believe this indicates the importance of matching the detonation velocity and the sonic velocity for successful explosive welding. Note Added in Proof. High quality explosive welds of lead to steel have recently been obtained at ambient temperature using a low velocity (1000 M per sec) free running dynamite. The weld interface obtained is comparable to Fig. 1. 'S. H. Carpenter, R. H. Wittman, and R. J. Carlson: Proceedings of the First International Conference of the Center for High Energy Forming, Syracuse University Press, syracu.se, N. Y., in press. 'A. HI Holtzman and G. R. Cowan: Welding Risearch. Council Bull., No. 104, April, 1965. 'Metals Handbook, 8 ed., p. 1062, Metals Park, Ohlo. 'J. M. Walsh, M. H. Rice, R. G. McQueen, and F. L. Yarger: Phys. Rev., 1957, vol. 108, pp. 196-216; 'L. V. Al'tshuler, K. K. Krupnikov, B. N. Ledener, V. I. Zuchikhin,

Jan 1, 1968

By F. W. Schroeder

AT the annual meeting of the Institute 2 years ago, a paper,1 " Requirements of Refractories for Open Hearths," was presented by F. W. Davis and G. A. Bole of the U. S. Bureau of Mines. In a brief foreword, D. A. Lyon stated that the paper was not to report the results obtained but rather to present an outline to serve as a basis for discussion. The essential parts of an open-hearth furnace were described and the conditions under which they operate. Some constructive discussion followed the reading of the paper. One of the first fellowship investigations undertaken by the Bureau of Mines in 1924 under the cooperative agreement with Carnegie Institute of Technology, through the Metallurgical Advisory Board, was to determine service conditions of open-hearth refractories. The present paper gives the results of this work which was done in the Pittsburgh district and was in charge of the authors. Material contributions in the form of data were contributed by E. N. Bauer, J. W. Campbell, G. H. Pfeiffer and A. Grodner, Carnegie Institute of Technology research fellows. The study covered 18 mos.

Jan 7, 1926

NORTH AMERICA Number Members Alaska 31 Canada 302 Mexico 175 Newfoundland 3 United States Alabama 52 Arizona 131 Arkansas 9 California 723 Colorado 184 Connecticut 98 Delaware 19 District of Columbia 133 Florida 16 Georgia 6 Idaho 61 Illinois 241 Indiana 57 Iowa 7 Kansas 32 Kentucky 33

Jan 1, 1932

By HOMER L. WILLIAMS

WHILE some of the mining companies have been pumping a small amount of water for some time, it is only in recent years that large quantities of water have been encountered in the Tonopah district. The water appears to be in different zones or belts so that the draining of one property does not necessarily affect the one adjoining. Consequently, each company has its own pumping plant and its own conditions. The companies panes handling the largest amount of water are the Tonopah Extension Mining Co., Halifax Tonopah Mining Co., West Tonopah Consolidated Mining Co., and Great Western Consolidated Mining Co. The Halifax shaft is on the eastern end of the district and the other three properties on the western. The ore-bearing formation occurs at greater depth on -the eastern and western ends, hence the water problem in these properties.

Jan 1, 1921

By B. D. Saklatwalla

FOR the proper understanding of the inclusion of certain elements in this review it seems necessary to state the meaning of "rare metals." Certain elements occur in deposits limited in extent or concentration, so that the extraction of the element in relation to market conditions becomes uneconomical. Others may occur in extensive and rich deposits but the reduction of the metal may be difficult and costly. Both these conditions effect the same result, namely, make the metal rare and costly. As an example of the first kind may be mentioned radium and of the second, calcium.

Jan 1, 1939

By Harry H. Power

INDUSTRY has the right to expect the petroleum engineering schools to supply more than the minimum technical qualifications necessary to obtain or discharge the responsibilities of a particular job. The basic training, social and economic orientation, should go far beyond these minimum requirements. Petroleum engineering students should also be well grounded in the history of the oil business so that they may understand the industry's progress since the advent of the Drake well. Furthermore, according to P. H. Bohart, the schools "have a definite duty to help the students form a workable philosophy of life, which includes an appreciation of the service of science to mankind, and a belief in the obligation of the individual who enters a profession to exalt himself by continuing his studies and growth so that he may never cease making contributions to the advancement of science and industry."

Jan 1, 1948

By C. O. Tarr, G. V. Smith, R. F. Miller

METALLURGISTS have long recognized that the Fe3C type of carbide is not a stable phase in steel and that, given sufficient time, it will decompose with formation of graphite, at least at temperatures below about 2050°F.1 This slow graphitization has never been of much concern to users of hypoeutectoid steels, for in such steels it occurs only during prolonged exposure at elevated temperature. In 1935, Kinzel and Moore2 reported complete graphitization of the carbide of a 0.1 5 per cent carbon steel that had been in senrice for about 26,000 hr. at a temperature of about 1100° to 1200°F. In discussing this paper, both Mathews and Sauveur reported graphitization of slightly hypereutectoid steels. In an extensive investigation of graphitization of high-purity iron-carbon alloys, Wells1 produced graphite at 7o0°C. (1290°F.) in an alloy containing as little as 0.13 per cent carbon, and showed that graphite may precipitate either directly from austenite or from decomposition of Fe3C, also that the rate of graphitization tends to increase with increase of temperature, at least up to a certain point, and with the presence of graphite nuclei. Jenkins, Mellor and Jenkinson,3 studying the structural changes in carbon steels ranging from 0.17 to 1.14 per cent carbon during stress-rupture tests at elevated temperature, obsenred graphite in an aluminum-killed 0.40 per cent carbon steel after fracture in 4340 hr. under a stress of 17,900 lb. per sq. in. at 840°F. and in many of the steels after stress-rupture test at 1200°F. Unstressed samples of 0.60, 0.86 and 1.14 per cent carbon steels graphitized almost completely in 360 hr. at 1200°F., while samples of 0.90 and 1.10 per cent carbon steels were somewhat graphitized, and steels containing 0.24, 0.40 and 0.57 per cent carbon showed no sign of graphite. Their results indicate that graphite precipitates the more readily the higher the carbon content, though this tendency is influenced to some extent by deoxidation practice, and that graphitization is accelerated by plastic deformation. In a recent study of the graphitization of 0.4 and 0.6 per cent carbon steel strip, made by M. A. Hughes,4 it was found that at 1200°F. graphite appeared after 72 hr. in aluminum-killed but not in silicon-killed steel, and that the rate of graphitization was increased by slow cooling from 1600°F. and by cold-working prior to annealing. In creep tests of normalized o. I 5 per cent carbon steel killed with 2.5 lb. of aluminum per ton, at the U. S. Steel Corporation laboratory at Kearny, spheroidization and some graphitization were found after 3000 hr. at 1000°F. under a stress as low as 15m lb. per sq. inch.

Jan 1, 1944