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By James A. Barr

When phosphate mining operations first commenced in Tennessee the loss of both high- and low-grade material was large, because of the crude hand methods employed. Practically all rock smaller than 2 in. was thrown back into the pits and covered with the overburden of subsequent openings. With the advent of mechanical washers and other mining machinery, together with the abolishing of the contract system, the waste has been steadily diminished, until at present only the finest sand is being rejected; and even this is not lost, for in the majority of cases the water, slime, and sand from the washers are run into large settling ponds where practically all of the phosphate-bearing material is caught and stored for future use, or until it is profitable to ship lower grades. The latest equipment used to recover the fine and lower-grade phosphate sand includes Dorr thickeners, settling tanks, Dorr classifiers and settling ponds served by locomotive cranes with clam-shell buckets, making it possible to save material averaging as fine as 200 mesh. TO attempt saving finer material would necessitate a different type of drier, which might be patterned after the multiple-deck roasters. The present tailing runs from 15 to 25 per ccnt. of available phosphate, which, howrever, as mentioned before, does not represent a total loss to possible future operations. The demand of the consumer is the greatest factor in regulating the recovery at present. In the mining of blue rock, which does not require washing treatment, the main waste material is the capping of low-grade kidney formation, generally used for backfilling of the rooms. By reason of the introduction of improved methods in the early stages and the re-mining of territory skimmed over at the start, at the present time the net result of all operations is a comparatively small loss. One of the largest temporary losses in the industry occurs in the Florida pebble district where the recovery of phosphate runs about 25 per cent. The loss is classed as temporary because most of the tailing has been collected in ponds and piles, where it may be reclaimed in the future should developments or improved processes warrant. In cleaning the Florida pebble phosphate, aside from the elutriatisn

Jan 1, 1916

By R. C. de Lange

An improved replica technique is developed for a nondestructive study of the nucleation and growth of fatigue cracks. Three different growth stages of a fatigue crack were observed. An initial stage of high growth rate is followed by a long period of very slow growth, until finally a third period of high growth rate leads to fracture. THE metal-fatigue process is of a very complex nature. The experimental approach towards fatigue is susceptible to many minor influences which, together with the unavoidable scatter in testing results, makes the interpretation a matter of extreme care. The generally accepted fact that, in a homogeneous material, the fatigue cracks start at a free surface indicates that surface studies may contri-but in an essential way to a better understanding of the fatigue mechanisms. Indeed metallographic observations of the fatigue phenomena have been very fruitful in the last decade. The study of extrusions, intrusions, and persistent slip bands has contributed much to the present knowledge of the early processes in fatigue.' The drawback of the current metallographic techniques lies in the fact, however, that either observations of fatigue phenomena had to be made in a destructive way after an only partly executed test or a sequence of observations on the same test bar was only possible on notched specimens.2 4 In both cases an uncertainty exists as to the nucleation and growth of the fatigue crack in an unnotched test bar, where the crack can start at any place of a large area and develops in a test bar, which is macroscopically

Jan 1, 1964

By Joseph Pogue

THE writer visited the Muzo emerald mines in July, 1915, and spent six days in their study. This paper embodies the results of his observations, plus information personally communicated by Robert Scheibe, FIG. 1.-SKETCH MAP SHOWING APPROXIMATE LOCATIONS OF ALL IMPORTANT EMERALD MINES AND PROSPECTS IN COLOMBIA. (Data in part supplied by Robert Scheibe, July, 1915.) Professor of Geology in the Mining Academy of Berlin, who at the time of the visit was completing a detailed field investigation of nearly a year's duration of the emerald deposits of Colombia. An elaborate account of this valuable work may be expected at a future date from the pen of Professor Scheibe.

Jan 5, 1916

By Alistair Frame

INTRODUCTION In April 1988 discussions were about to start with BP on the possibility of buying their- mineral interests, and it took a long time to arrange a deal. I will talk about RTZ without BP Minerals, look at the new RTZ with BP Minerals, discuss the outlook for metal prices, and review the problems in South Africa and develop the case against sanctions on that country. RTZAT THE END OF 1988 Late in 1987, after completing a worldwide review of our strategic thrust, we decided: 1. That the business focus would be to remain a major diversified natural resource group with interests in related industries. 2. To divest non-core and low growth businesses. 3. To develop a logical acquisition plan. 4. To emphasise organic growth and, most importantly, to enhance shareholders' wealth by capital increase and a progressive dividend policy. Subsequently, we concluded that we should sell our oil and gas business and dispose of several assets for which we saw little growth potential. The disposal programme raised some U.S.$ 1,600 million, representing a significant capital gain on our various investments. All transactions were carried out by our small Head Office staff in London, without the help of merchant banks and lawyers, and we were able to safeguard the employment of our staff in all these operations. The most interesting disposal was of our oil and gas interests. Before the 1987 strategic review, we had ambitions to develop our oil and gas interests and to become the leader in the second division of European oil companies. Our interests, which were purely in exploration and production of oil and gas, consisted of the 100% owned RTZ Oil and Gas company, and 29% of LASMO, a publicly quoted U.K. oil and gas company with extensive worldwide interests. LASMO, in turn, owned 25% of Enterprise Oil, one of the more successful of the North Sea oil exploration and production companies. Prior to the end of 1987, our intention was to acquire control of both LASMO and Enterprise. However, when we evaluated the net asset value of these two companies based on our oil price assumptions, which were pessimistic for the next five years or so, we concluded that they were both trading in the market at significant premiums. This, taken with the additional premium required for acquisition and the high cost of exploration, led us to conclude that, since funds could undoubtedly be used to better effect, we should sell our interests. Turning to the other major achievements in 1988, we commissioned, and built up to design levels in a very short period of time, the Morro do Ouro gold mine in Brazil. This mine reached its design output of 100,000 ounces of gold per year within three months of start-up, which was on time and under budget. We are now considering a possible expansion of this property. In South America, Utah International, Mitsubishi and RTZ arranged non-recourse finance, with post completion guarantees, for the giant Escondida Project in Northern Chile. Financing came from a group of banks in Japan, Germany and Finland -- the countries to which most of the concentrates will be sold -- and from the LEC. The average output of the mine for the

Jan 1, 1990

By C. F. Park

Hog Mountain is in the north central part of Tallapoosa County, Alabama, about 13 miles northeast from Alexander City. The Hog Mountain Mining and Milling Co. controls 1658 acres of land and is the only company operating in the district. The principal mine workings are in sections 10 and 15, T.24N., R.22E. The region has been visited by geologists many times, has been briefly described in several papers,' and mentioned in many others. No detailed map of the mine or vicinity has been published. The field work for this report was started in March, 1934, as part of the Public Works reemployment program. About a month and a half was spent mapping both the surface and underground geology. The mine owners and operators have cooperated in every way possible to facilitate the work. N. 0. Johnson, the mine engineer, E. W. Ellsworth, J. E. McCoy and J. G. Englebert have acted as assistants for part of the work. The University of Alabama and the State Geologist's office have aided materially by permitting free use of their libraries and laboratory equipment. Geography Hog Mountain forms a conspicuous ridge that rises to a height of a little more than 1000 ft. above sea level, and about 400 to 500 ft. above the adjacent country. The ridge is composed of granitoid intrusive rock and silicified schist that are more resistant to erosion than the surrounding softer schist. The topography of the area around the ridge is gently rolling and is typical of the subdued forms of the deeply eroded Southern

Jan 1, 1935

By C. F. Park

Hog Mountain is in the north central part of Tallapoosa County, Alabama, about 13 miles northeast from Alexander City. The Hog Mountain Mining and Milling Co. controls 1658 acres of land and is the only company operating in the district. The principal mine workings are in sections 10 and 15, T.24N., R.22E. The region has been visited by geologists many times, has been briefly described in several papers,' and mentioned in many others. No detailed map of the mine or vicinity has been published. The field work for this report was started in March, 1934, as part of the Public Works reemployment program. About a month and a half was spent mapping both the surface and underground geology. The mine owners and operators have cooperated in every way possible to facilitate the work. N. 0. Johnson, the mine engineer, E. W. Ellsworth, J. E. McCoy and J. G. Englebert have acted as assistants for part of the work. The University of Alabama and the State Geologist's office have aided materially by permitting free use of their libraries and laboratory equipment. Geography Hog Mountain forms a conspicuous ridge that rises to a height of a little more than 1000 ft. above sea level, and about 400 to 500 ft. above the adjacent country. The ridge is composed of granitoid intrusive rock and silicified schist that are more resistant to erosion than the surrounding softer schist. The topography of the area around the ridge is gently rolling and is typical of the subdued forms of the deeply eroded Southern

Jan 1, 1935

Hog Mountain is in the north central part of Tallapoosa County, Alabama, about 13 miles northeast from Alexander City. The Hog Mountain Mining and Milling Co. controls 1658 acres of land and is the only company operating in the district. The principal mine workings are in sections 10 and 15, T.24N., R.22E. The region has been visited by geologists many times, has been briefly described in several papers,' and mentioned in many others. No detailed map of the mine or vicinity has been published. The field work for this report was started in March, 1934, as part of the Public Works reemployment program. About a month and a half was spent mapping both the surface and underground geology. The mine owners and operators have cooperated in every way possible to facilitate the work. N. 0. Johnson, the mine engineer, E. W. Ellsworth, J. E. McCoy and J. G. Englebert have acted as assistants for part of the work. The University of Alabama and the State Geologist's office have aided materially by permitting free use of their libraries and laboratory equipment. Geography Hog Mountain forms a conspicuous ridge that rises to a height of a little more than 1000 ft. above sea level, and about 400 to 500 ft. above the adjacent country. The ridge is composed of granitoid intrusive rock and silicified schist that are more resistant to erosion than the surrounding softer schist. The topography of the area around the ridge is gently rolling and is typical of the subdued forms of the deeply eroded Southern

Jan 1, 1935

By C. F. Park

Hog Mountain is in the north central part of Tallapoosa County, Alabama, about 13 miles northeast from Alexander City. The Hog Mountain Mining and Milling Co. controls 1658 acres of land and is the only company operating in the district. The principal mine workings are in sections 10 and 15, T.24N., R.22E. The region has been visited by geologists many times, has been briefly described in several papers,' and mentioned in many others. No detailed map of the mine or vicinity has been published. The field work for this report was started in March, 1934, as part of the Public Works reemployment program. About a month and a half was spent mapping both the surface and underground geology. The mine owners and operators have cooperated in every way possible to facilitate the work. N. 0. Johnson, the mine engineer, E. W. Ellsworth, J. E. McCoy and J. G. Englebert have acted as assistants for part of the work. The University of Alabama and the State Geologist's office have aided materially by permitting free use of their libraries and laboratory equipment. Geography Hog Mountain forms a conspicuous ridge that rises to a height of a little more than 1000 ft. above sea level, and about 400 to 500 ft. above the adjacent country. The ridge is composed of granitoid intrusive rock and silicified schist that are more resistant to erosion than the surrounding softer schist. The topography of the area around the ridge is gently rolling and is typical of the subdued forms of the deeply eroded Southern

Jan 1, 1935

By Frederick Prime

IN this second supplementary list no titles to which an * is. Pre-fixed have been seen by the compiler; and he will be most thankful to have, any omissions or inaccuracies in the list sent to him to be published as a third supplement in the next volume of- the Trans-actions. The author is indebted to Prof. J. J. Stevenson, of New York, Prof. P. R. Uhler and John W. M. Lee, Esq., of Baltimore, and Lloyd P. Smith, Esq., of Philadelphia, for valuable assistance. OFFICE, ALLENTOWN IRON COMPANY, 230 SOUTH THIRD STREET, PHILADELPHIA, September 5th, 1881. ALABAMA. Geological Survey of Alabama. Report of Progress for 1879 and 1880, by Eugene A. Smith, State Geologist. Montgomery, 1881. 8vo., 158 pp., and 2 maps. CALIFORNIA. Omit Report of Hon. T. Butler King, in Supplement 1. For Trash's Geology and Industrial Resources, etc., in Supplement I., read Tyson's, etc: Fremont's Memoir on Upper California, is also published as XXXth Congress, 1st Session. Senate Mis. Doe., No 148, and has a map. For Randall's Report in Supplement I, read Report of the Special Committee in favor of a Geological Survey, submitted by Mr. Randall, April 24th, 1851. a.d., 1851. 8vo., 1.9 pp. XXXIst Congress, 1st Session, Sea. Ex. Doc., No. 47, Part 2 [Part 1 is Tyson's Report.] Report of the Secretary of War in further compliance with the Resolution of the Senate, calling for Copies of

Jan 1, 1881

Albin, B. R Billings, Mont. '28 Amster, Nathan L 25 Broad St., New York, N. Y. '28 Bache, Jules S 42 Broadway, New York, N. Y. '28 Barrett, C. P 5338 Harper Ave., Chicago, 111. '28 Bayless, William S Russ Bldg., San Francisco, Cal. '28 Bean, Louis, H 60 E. 42nd St., New York, N. Y. '28 Beatty, Ross J Room 604, 6 N. Clark St., Chicago, III. '28 Benwell, Oswald F Hold Mags. '28 Beymer, Albert S., V.P., Keystone National Bank Pittsburgh, Pa. '28 Blumenthal, Hugo 44 Pine St., New York, N. Y. '28 Boettcher. Charles Ideal Cement Bldg., Denver, Colo. '28 Bowlus, Thomas H., Banker, Pres., Allen County State Bank Iola, Ran. '28 Brown, Colvin B Chamber of Commerce, Washington, D. C. '28 Burt, Maxwell Struthers Southern Pines, N. C. '28

Jan 1, 1934

By AIME AIME

A. A. Holland, Consulting Engineer, Toronto, Ont.-I noticed in this discussion of locations in which radium is found, no mention is made of the recent deposits discovered in Ontario. While radium is not a subject with which I am very familiar, I took an interest in this deposit on account of its novel occurrence. It is found in Haliburton County, near Wilberforce, Ontario, associated with a quartz free pegmatite, in a "break" that I understand can be traced for two miles. This "break" marks the contact between the limestone and syenite and contains numerous cavities or vugs. The gangue, on account of its deep purple, appears to :be amethyst.

Jan 1, 1930

By A. W. Schlechten, W. J. Kroll

As this paper is written, the only method for the commercial production of lithium metal is by the fusion electrolysis of LiCl-KCl mixtures, as first proposed by Guntz.2 The details of the industrial process have not been made public but Osborg8 stated that an efficiency of more than go pct is obtained with a lithium metal recovery above 95 pct and that the metal is 99.5 pct pure. Pletenev9 gave a power consumption of 66 kw-hr per kilogram of lithium metal produced with a salt consumption of 9 kg of LiCl and 0.4 kg of KCI. Pletenev's figures indicate a somewhat lower recovery than that given by Osborg. In a recent report on German lithium plants, Motock7 gives figures that are also less favorable than those reported by Osborg. At the German plants the lithium recovery in electrolysis was only 83.4 pct, with a power consumption of too kw-hr per kilogram of lithium. The metal averaged only 97 pct pure, with sodium and potassium as the chief impurities. The presence of SO2, SO3, Si02, Ba, Ca, and appreciable amounts of Na and Fe2O3 were especially disturbing in the electrolysis, and it was necessary to run the cell for some time to eliminate most of these impurities and condition the bath. It may be noted here that most of these impurities do not interfere with a thermal reduction process. These facts show that the present method of producing lithium is fairly efficient and would suggest that other methods could not compete. However, fusion electrolysis has certain drawbacks, such as the necessity of supplying costly, low-voltage direct current and of collecting and processing the anodic chlorine if it is not to be wasted. An even greater disadvantage is that lithium chloride must be used for an electrolyte. It is one of the most expensive salts of lithium, since it cannot be produced in anhydrous form by precipitation from aqueous solution, as is done with LiF or Li2CO3. The reduction of lithium by a vacuum process similar to the ferrosilicon method for the production of magnesium would have certain advantages. Small units, such as Pidgeon retorts, would give flexibility of production to meet demand, and a small plant would require moderate capital outlay. There is a possibility of using idle Government-owned magnesium plants for such purposes. The raw materials needed for vacuum thermal reduction would not have to be extremely pure, especially with respect to the iron and calcium content. This paper describes a series of experiments to determine the effectiveness of various agents for the reduction of lithium compounds. The investigation is part of a program of vacuum metallurgy con-

Jan 1, 1947

By W. Gundaker, F. C. Schwerer

Natural chromium-bearing spinels (chromites), which are used as refractory materials in basic steelmaking, are the only commercially important chromium ore and are also encountered as difficult-to-separate contaminants in ore deposits of potential economic value. Techniques for characterization and separation of ore materials frequently are dependent on the magnetic properties of the constituent minerals. An experimental program was initiated to explore the effects of temperature and of simple mechanical and thermal treatments on the static magnetic properties of several ore-grade natural chromites. Studies of the temperature dependence of the magnetic properties showed that the natural chromites, which are dilute in the magnetic ions Fe and Cr, order magnetically only at cryogenic temperatures. However, mechanical treatment in the form of crushing produces a magnetic component that is ordered at room temperature and that is of sufficient strength to alter magnetic-separation characteristics. The additional magnetic component apparently is associated with surface structures which develop during crushing and disappear after heating to above about 500°C. Preliminary studies indicate that this surface structure enhances the susceptibility of the chromite grain surfaces to gas reactions at moderate temperatures.

Jan 1, 1976

By H. C. George

As the basis for a round table discussion of Petroleum Engineering Education for the February, 1930, meeting of the Petroleum Division, A. I. M. E., the following questions were sent to about 60 of the leading engineers and educators in the petroleum industry: 1. Should there be any changes in the curricula of our courses in petroleum engineering to meet the changing demands of the Industry? If so, what changes?] 2. Should courses in petroleum engineering be offered through university extension? 3. Should the universities offer correspondence courses in petroleum engineering? 4. What should be the character of the graduate work offered in petroleum production engineering? 5. Should summer work in the oil fields, on pipe lines, or in oil refineries be required of undergraduates? If so, how much and of what character? The following men replied to the questions: G. B. Corless, Humble Oil & Refining Co., Houston, Texas. J. R. McWilliams, Skelly Oil Co., Tulsa, Okla. W. W. Scott, Humble Oil & Refining Co., Houston, Texas. H. H. Power, Gypsy Oil Co., Tulsa, Okla. L. G. E. Bignell, Oil K. Gas Journal, Tulsa, Okla. E. L. Estabrook, Pan American Petroleum & Transport Co., New York, N. Y. F. P. Donohue, Pan American Petroleum & Transport Co., New York, N. Y. C. 0. Rison, lndian Territory Illuminating Oil Co., Bartlesville, Okla. L. B. Holland, Phillips Petroleum Co., Bartlesville, Okla. H. J. Kemler, Shell Petroleum Corpn., St. Louis, Mo. C. A. Bonine, Pennsylvania State College, State College, Pa. J. 0. Lewis, Dunn & Lewis, Tulsa, Okla. A. G. Heggem, Tulsa, Okla. J. M. Lovejoy, Petroleum Bond & Share Corpn., New York, N. Y. B. B. Boatright, Colorado School of Mines, Golden, Colo. A. C. Ruble, Union Oil Co. of California, Los Angeles, Calif. J. B. Umpleby, Goldelline Oil Corpn., Oklahoma City, Okla. R. S. Knappen, Gypsy Oil Co., Tulsa, Okla. K. C. Heald, Gulf Companies, Pittsburgh, Pa. K. C. Sclater, Exchange National Bank Bldg., Tulsa, Okla. F. G. Tickell, Stanford University, Stanford University, Calif.

Jan 1, 1930

THE Institute assembled in Packer Hall of the Lehigh University, the President, Mr. David Thomas, of Catasauqua in the chair. Professor Henry Coppée, President of the Lehigh University, made an address of welcome to the Institute, and placed at its disposal a convenient hall for purposes of meeting. Mr. Thomas tendered his resignation as President of the Institute, as advancing years prevented him from actively participating in its meetings. The Institute declined to accept the resignation, and, on the assurance that active duties would not be expected of him, Mr. Thomas was induced to withdraw it. Invitations were received from Mr. B. C. Webster, President of the Lehigh Zinc Company, to visit the mines and works of the company; from Mr. Charles Brodhead, to visit the Chapman Slate Quarries; and from the Lehigh Coal and Navigation Company, to visit their works at Summit Hill and Mauch Chunk and the Nesquehoning Tunnel. The Council reported the names of persons already elected in the two classes of members and associates. The following resolutions were passed : Resolved, That a committee of three be appointed, who shall take into consideration the printing and publishing of papers originating with the Institute, and that a uniform system as regards size and execution be adopted. The committee appointed consisted of Messrs. R. W. Raymond, E. B. Coxe, and the Secretary. Resolved, That the Council design and prepare a seal for the Institute at the earliest practicable time. Resolved, That a committee of six, with power to add to its numbers, be appointed to examine into the question of the more economical production of iron in this country. The committee appointed consisted of Messrs. G. W. Maynard,

By C. F. Riisness, E. R. Parker

THAT grain size has a great effect on the mechanical properties of metals has been recognized for a long time. Bassett and Davis1 in 1919 did excellent work in [ ] determining the effect of grain size on the hardness of brass. About the same time Jeffries2 and Sykes3 ascertained the effect of grain size on the strength and ductility of several metals at temperatures ranging from 80°K. to their melting points. When creep was recognized as an important property of metals, those engaged in the study of this property tried to determine the effect of grain size 4-9 on creep rates. Unfortunately, most of the investigations were conducted on only two grain sizes, often designated simply as "fine" and "coarse." It is well known that at high temperatures coarse-grained test bars creep less than fine-grained bars. The relation between grain size and size of test bar, [ ] however, has been frequently overlooked. In his early work, Jeffries2 showed that the number of grains in the cross section has a more important influence on the properties of the material than the actual grain size. More recently Hanson and Sandford10 and Pell-Walpole,11 in their measurements of the creep and tensile properties of tin, tested a wide range of grain sizes and correlated the grain size with the strength. Hanson9 later established the relation between the number of grains in the cross section and the. creep rate: At high temperatures, generally a coarse-grained structure is considered superior in creep to a fine-grained structure, but it is evident that for a given bar size continuously increasing the grain size will

Jan 1, 1944

Page McGREGOR, A. G.-Features of the New Copper Smelting Plants in Arizona. Discussed by L. D. Ricketts, E. P. Mathewson 2145 HOWARD, L. O.-The Basic-Lined Converter in the Southwest. Discussed by Walter Douglas, E. P. Mathewson, Kuno Doerr 2145 SAMUEL, J. MOORE-Determination of Dust Losses at the Copper Queen Reduction Works. Discussed by Walter Douglas, E. P. Mathewson, S. J. Jennings, C. E. Arnold, A. G. McGregor, L. D. Ricketts 2148 MORSE, H. W., AND TOBELMANN, H. A.-Leaching Tests at New Cornelia. Discussed by H. W. Morse, Lawrence Addicks, G. D. Van Arsdale, S. J. Jennings, F. S. Schimerka, C. G. Grabill, F. N. Flynn, Stuart Croasdale 2151 LAIST, FREDERICK, AND ALDRICH, HAROLD W.-The 2,000-Ton Leaching Plant at Anaconda. Discussed by F. N. Flynn, E. P. Mathewson 2159 ADDICKS, LAWRENCE-Possibilities in the Wet. Treatment of Copper Concentrates. Discussed by F. N. Flynn 2160

Jan 12, 1916

By Harvey Cline, Donald P. Ferriss

THE violent outgassing of commercial tungsten and other refractory metals when melted in an electron beam zone refining apparatus1"3 is dealt with experimentally by one or both of two approaches. One is to provide a suitable emission current control1,2 the other is to purify the metal in the solid state before melting.4 The first of these is usually sufficient, but the authors chose also to investigate the source of the troublesome gases and to devise means of solid-state purification. Some further insights into the use of tungsten as a structural material at temperatures near its melting point were also revealed in the course of the work. One may speculate on the causes of gas formation in tungsten at high temperature by inferences from the literature and an examination of the impurities in commercial wire. Davenport5 observed microporosity in both tungsten and molybdenum filaments heated to several hundred degrees below their melting points. Studying the function of oxygen in molybdenum welds, Perry, Spacil, and wulff8 attributed similar porosity to the disproportionation of Moo2 to molybdenum metal and Moo3. Tungsten dioxide also disproportionates7 above 2000oC to yield WO3 vapor at considerable pressure. Commercial tungsten contains some 5 to 20 wt ppm O and a similar concentration of carbon depending on the details and precautions of processing. Therefore, evolution of CO is also a strong possibility as a source of gas at high temperatures. Furthermore, even for activities in the order of 0.01, it may be calculated that the pressure of CO at 3000°C would be over 4000 psi, which is in excess of the tensile strength of tungsten at this temperature.9,10 Powder metallurgy tungsten contains some 0.02 pet Fe and 0.002 to 0.005 pet of the elements Ni, Si, Al, Ca, Mn, Mg, and Mo; at temperatures over 2800°c, therefore, these elements will exhibit appreciable vapor pressure, though small compared to that of WO3 and CO. Some of these impurities may react to form high-pressure monoxides such as SiO and A10. Finally, dissolved and occluded nitrogen is an ever-present source of high-pressure gas. Commercial Type 218, General Electric filament wires, 0.025 in. diam, were heated by resistance in 10 -4 mm of Hg and in argon or hydrogen at pressures from 50 µ to atmospheric. For temperature determinations in vacuo, the Jones - Langmuir8 current-temperature relationship was employed. For gaseous atmospheres, the burn-out temperature was assumed to be the same as in vacuo so that a small, constant correction could be made for temperatures below burn-out conditions (i.e., local heating to failure). Several dozen experiments may be summarized by pointing out some structural observations. At 3050oC in 1 atm of A, porosity is very evident after 30 min, as shown in Fig. 1. For the section in Fig. 2, failure occurred 200°C below the melting point and many voids have grown in the grain bound-

Jan 1, 1962

By E. S. Rowland, J. Welchner, R. H Marshall

This paper presents results on an extension into the realm of high-carbon steels of some work recently published1 on the effects of time at temperature, quenching temperature and prior structure on the hardenability of one 0.20 and four 0.40 per cent carbon alloy steels. It was shown at that time that unless the conditions of time, temperature and prior structure are substantially the same in performing the hardenability test as in conducting hardening of parts in production, the correlation of hardenability information with the hardness and properties of production parts is often not of satisfactory accuracy. The general effects of these variables on the austenitic grain size, distribution of excess carbides and critical cooling rate have been known for many years and one or more have been investigated by Shepherd,2,3 Davenport and Bain,4 Digges,5,6 Digges and Jordan,' Post and associates8 and Roberts and Mehl,9 to mention only a few. There has been no systematic investigation, however, into the quantitative variations produced on the hardenability of commercial high-carbon steels by changes in these factors of time, temperature and prior structure. Procedure A plain carbon hypereutectoid steel, S.A.E. 52100 and Graph-Mo, a molybdenum-bearing high-carbon steel containing some graphite, were chosen for this investigation. The chemical analyses of these electric-furnace steels are given in Table I. The procedure used was exactly that reported previously,' hence the details will not be repeated here. Normalized (165o°F.) and spheroidized prior structures were utilized on all steels with hot-rolled and quenched (I600°F. oil) prior conditions added for the plain carbon steel. The end-quench test developed by Jominy10 was sclected for use in this investigation and, with the noted exceptions, the American Society for Testing Materials standard procedure was followed. The effect of time at temperature was examined at intervals of o, 10 and 40 min. and 4 hr., and a few 16-hr. tests were run. Salt-bath heating of the specimens was employed to control and minimize the

Jan 1, 1944

By R. H. Marshall, J. Welchner, E. S. Rowland

This paper presents results on an extension into the realm of high-carbon steels of some work recently published1 on the effects of time at temperature, quenching temperature and prior structure on the hardenability of one 0.20 and four 0.40 per cent carbon alloy steels. It was shown at that time that unless the conditions of time, temperature and prior structure are substantially the same in performing the hardenability test as in conducting hardening of parts in production, the correlation of hardenability information with the hardness and properties of production parts is often not of satisfactory accuracy. The general effects of these variables on the austenitic grain size, distribution of excess carbides and critical cooling rate have been known for many years and one or more have been investigated by Shepherd,2,3 Davenport and Bain,4 Digges,5,6 Digges and Jordan,' Post and associates8 and Roberts and Mehl,9 to mention only a few. There has been no systematic investigation, however, into the quantitative variations produced on the hardenability of commercial high-carbon steels by changes in these factors of time, temperature and prior structure. Procedure A plain carbon hypereutectoid steel, S.A.E. 52100 and Graph-Mo, a molybdenum-bearing high-carbon steel containing some graphite, were chosen for this investigation. The chemical analyses of these electric-furnace steels are given in Table I. The procedure used was exactly that reported previously,' hence the details will not be repeated here. Normalized (165o°F.) and spheroidized prior structures were utilized on all steels with hot-rolled and quenched (I600°F. oil) prior conditions added for the plain carbon steel. The end-quench test developed by Jominy10 was sclected for use in this investigation and, with the noted exceptions, the American Society for Testing Materials standard procedure was followed. The effect of time at temperature was examined at intervals of o, 10 and 40 min. and 4 hr., and a few 16-hr. tests were run. Salt-bath heating of the specimens was employed to control and minimize the

Jan 1, 1944