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By Valentin R. Garfias

The world's production of petroleum during 1926 is estimated at 1,096,000,000 bbl., an increase of about 29,000,000 from that of 1925 and somewhat larger than the average during the last 4 years, which is about 1,049,000,000 bbl. The daily average during the year may be estimated at 3,000,000 bbl. of which the United States produced 2,123,000 and other countries 877,000. The outstanding developments during the year have been the decline of the Mexican fields, the counterbalancing of this decline by the increase in Venezuelan and Russian production, and increases in Roumania and Colombia. During 1926 the United States, Mexico and Russia retained their relative positions as the three leading producers, while Venezuela probably outranked Persia for fourth place, Roumania passed Dutch East Indies for sixth, and Colombia moved from sixteenth to the eleventh position. It further appears that should present conditions develop normally throughout 1927, it is not improbable that Mexico will be outranked by Russia as the second oil-producing country and that the increased yield of Colombia will place this country in the eighth or ninth position, and ahead of India. The United States and Mexico should produce in 1926 about 79 per cent. of the world's total and the aggregate of the seven leading countries should be close to 95 per cent. of the total. It is interesting to note that about 85 per cent. of the total comes from fields on the American continent, the United States accounting for about 71 per cent., and Spanish-American countries and Trinidad for 13 per cent. Production of countries other than the United States and Mexico has gradually increased during the last four years and now represents about 21 per cent. of the total. The United States easily retains its long standing leadership with a total yield of 775,000,000 bbl., or an average daily yield of 2,123,000, representing about 71 per cent. of the total, which is about equal to that of the previous year. An increase in production of about 11,000,000 bbl. is indicated by the statistics so far available. It will be noted that the American production in the last 4 years has averaged about 746,000,000 bbl. yearly and that this uniformity, as well as the marked increases

Jan 1, 1927

By AIME AIME

ON Thursday a most interesting symposium on "Gases in Metals" was held, with both morning and afternoon sessions. The morning was devoted principally to the considerations of the steel maker, the nonferrous field being taken up in the afternoon period. Dr. John Johnston, as chairman, introduced the subject with "A Short Analysis of the Gas-metal Problem and Its Practical Importance." He then introduced P. H. Brace who explained in considerable detail the various vacuum fusion and other methods in use at present, both here and abroad, in the study of "gases" in metals. He was fol¬lowed immediately by H. W. Graham on "The Effect of Oxygen in Steel." The papers elicited considerable discussion, the point being particularly noted by both Dr. Rawdon and Dr. Sauveur that a knowledge of "total oxygen" alone is not sufficient information for the metallurgist, distribution of oxygen being probably the more important. Dr. Johnston, in commenting on the lack of agreement among many of the methods now in use, such as the Ledebur and vacuum fusion, spoke of the contemplated plan of the Iron and Steel Division to have a number of standard samples analyzed by many laboratories by the various methods, the Bureau of Standards acting as a clearing house, so that more definite information may be obtained on the comparative accuracy of the method.

Jan 1, 1933

By J. D. Livingston

THE hardening of alloys by the precipitation of a second phase has long been an important technological process. One approach towards improving our understanding of this phenomenon has been a correlation of mechanical properties with such parameters as particle size and inter par ticle spacing.' Several reviews of such data have appeared.2-4 A major limitation to this approach has been that for most alloys the particles are submicroscopic in size in the range of optimum hardness. Precipitation-hardening copper-cobalt alloys, therefore, are of interest, because the ferromagnetic properties of the precipitate make it possible to measure particle size, number of particles, and so forth, from magnetic measurements alone.5, 6 Livingston and Becker7 have applied these techniques to a study of precipitation hardening in an alloy of 2 pct Co in copper. It was found from magnetic measurements that nearly all the cobalt to be precipitated was out of solution within a few minutes at 600°C, whereas the peak in tensile yield stress was not attained until a much longer aging time. Thus during the first 1000 min of aging time at 600°C the Yield stress was increasing while a constant volume of precipitate was coarsening, i.e., while particle size and interparticle spacing were increasing. Peak yield stress was reached at an average particle radius of about 70A. The earlier study was confined to one alloy at one aging temperature, so that the volume fraction of precipitate was fixed and, therefore, particle size and interparticle spacing could not be independently varied. The work has now been extended to several alloys of varying percentage cobalt in copper, and to aging at various temperatures. It was hoped that such a study might clarify the relative importance to precipitation hardening of particle size, interparticle spacing, and volume fraction of precipitate. EXPERIMENT The alloys studied contained 0.7, 1.3, 2.0, and 3.2 wt pct Co in copper. They were prepared from electrolytic copper and electrolytic cobalt in a vacuum -induction furnace, worked to 3/8-in.-diam rod, and machined into tensile specimens with a gage section 1 1/2 in. long and 3/16 in. in diam. All specimens were given a solution treatment consisting of a 30-min anneal in nitrogen at 1000° C followed by a quench into iced brine. Subsequent aging was done in nitrogen and followed by a water quench. Average grain diameter was approximately 0.01 in.

Jan 1, 1960

Discussion of the paper of HOWLAND BANCROFT, presented at the Salt Lake meeting, August, 1914, and printed in Bulletin No. 91, July, 1914, pp. 1767 to 1769. THEODORE SIMONS, Butte, Mont. (communication to the Secretary*). -While preparing maps and models for use in mining litigations the writer was frequently confronted with the problem referred to in Mr. Bancroft's paper. His chart gives the apparent angle of dip with which a vein should be plotted on a vertical section not at right angles to the strike of the vein. For a quick determination of this apparent angle the writer has used an exceedingly simple graphical method, which he believes may prove helpful to engineers engaged in practical work. It is submitted, not as a criticism of Mr. Bancroft's paper, but as a means of solving the same problem when no chart is available and when calculations would consume too much time. The writer's method requires merely a few lines marked off on a piece of tracing cloth, as shown in Fig. 1: Draw line be on any convenient scale. At b erect a perpendicular, ba. By means of a protractor cut off on ba a number of angles within the probable range of variation of dip, so that a line connecting a and c, for instance, forms an angle of 60° with be, etc. With b as a center and be as a radius, draw a circle through c. This completes the tool for solving the problem. Fig. 2 represents the line of strike of the vein and db the trace of the vertical plane on which the vein is to be plotted with the apparent angle of dip. A° is the angle which this plane makes with the strike. Fig. 3 shows the application of the method: Place line cb of tracing over line db of Fig. 2 and move fore and back until line of strike becomes tangent to the circle. Connect d with the point (a) that marks the true angle of dip as found by measurement in the mine (60° in the case illustrated). The angle adb is the apparent angle of dip (C°) to be used in the vertical section. Proof.-As stated in Mr. Bancroft's paper, the apparent angle of dip is: tan C° = sin A° tan B° (1)

Jan 12, 1914

By Blamey Stevens

(San Francisco Meeting, October, 1911.) My previous paper is entitled, The Laws of Igneous Emanation Pressure. The present paper lays no claim to the exactitude and completeness of a law, since it is of a provisional nature and may be disregarded when experiments have established a basis for more exact reasoning. The general physical states in which aqueous emanations may occur are first considered. The possible physical conditions under which the mineral elements may occur in emanations are then discussed, and a classification of deposits, dependent on emanation, is proposed. A system of scientific experimental investigation is outlined, and it is shown that the physical and chemical properties of emanation may be exactly determined thereby. The investigation is urged as feasible and simple, and not necessarily requiring large and costly apparatus. It is the only step necessary to make possible the formulation of a complete set of laws of igneous emanation. Process of Emanation. In a rising column, magma ranges in temperature from 900° to 1,200°C. Exhalation must begin at some fairly great depth. What this depth may be we can only surmise, since no experimental evidence is available. Exhalation, however, continues as the magma flows upward, until at another level the occluded gases have all escaped. This depth is probably upward of 5,000 ft. (See Fig. 1.) All exhalations must come from between these two levels. As the whole emanation is the sum of the exhalations and residues, the residues must come from below the uppermost level. They will be most abundant when coming, from those parts of the intrusion which have solidified below the lower level.

Apr 1, 1912

By J. E. Neal, C. T. Naber, O&apos

Silicon thin films were deposited by electron beam evaporation in an ultrahigh vacuum onto (0001) and (1102) sapphire substrates. Attempts were made to correlate the structural properties of the deposited silicon films with the following: 1) substrate orientation, 2) substrate surface condition, 3) substrate temperature, and 4) deposition rate. The substrate temperatures were varied between 500° and 1000°C and the deposition rates were varied between approximately 50 and 700A per min. The following sapphire surface treatments were investigated: 1) annealing in the ultrahigh vacuum at 1200° C; 2) heating in a hydrogen atmosphere at about 1350°C; and 3) etching with silicon by evaporating silicon onto sapphire substrates heated to 1200° or 1300°C. Twinned silicon films were occasionally formed at substrate temperatures between the 800° and 1000°C on unprocessed mechanically polished substrates; however, the reproducibility and crystallinity of these films were generally poor. Single-crystal and twinned silicon films were formed at substrate temperatures between 700° and 1000°C on substrates which were silicon-etched at 1300°C prior to deposition. Fiber texture films were formed at substrate temperatures between 500° and 700°C. The (111) lattice plane of the silicon single-crystal films was parallel to the (0001) sapphire plane and the (100) silicon plane was parallel to the (1102) sapphire plane. TECHNIQUES are well-established for growing single-crystal silicon thin films on sapphire by chemical methods.'-* Vacuum epitaxial techniques have a number of advantages over chemical epitaxial techniques in the fabrication of thin film microcircuits.5 One of the most significant is that vacuum techniques are compatible with well-established procedures for forming vacuum-deposited thin-film resistors, capacitors, and interconnections. Salatna, Tucker, and young6 recently reported the formation of relatively poor crystalline-quality silicon films on sapphire by electron beam evaporation in a vacuum of about 7 x 10-7 Torr. The purpose of the investigation described here is to determine the relationships between the structural properties of silicon thin films deposited on sapphire substrates by electron beam evaporation in an ultra-high vacuum and the following: 1) substrate orientation; 2) substrate surface condition; 3) substrate temperature; and 4) deposition rate. The substrate temperatures were varied between 500° and 1000° C and the deposition rates were varied between approximately 50 and 700A per min. Two orientations of sapphire were used: (0001) and (1102). The thick-nesses of the films were between 8000 and 16,000A. The morphology and crystallinity of the deposited films and substrate surfaces were investigated by optical microscopy, electron microscopy, and electron diffraction. APPARATUS AND PROCEDURE A cross section of the ultrahigh-vacuum thin-film evaporator is shown in Fig. 1. The bell jar is stainless steel and copper gaskets are utilized at all seals. High vacuum is attained by a 6001iter per sec ion pump and a titanium sublimation pump. Sorption pumps are used to rough the system to a pressure of about 10 µ prior to starting the ion pump. Vacuums in the 10- 10 Torr range were attained after baking the system at about 250°C for 8 hr. Vacuums in the 10-8 to 10-9 Torr range were maintained during silicon evaporation. The silicon charges, which were cut from p-type single-crystal boules which had resistivities between 2000 and 4500 ohm-cm, were placed in the water-cooled copper crucible of a 180 deg bent-beam 5-kw electron beam evaporator. During evaporation, a molten zone was formed in the top center of the silicon charge, and the portion of the silicon charge in contact with the water-cooled crucible remained solid. The substrate heater, which has been described

Jan 1, 1969

By H. A. Guess

AT the outset, said Mr. Guess, I may say that although I believe the present engineering courses in the various colleges and universities could be arranged to give the student within the same time limit a broader general education of un- doubted value, still I do not agree with the view held by many that engineers in comparison with those of other occupations-let us say doctors, lawyers, bankers, and so-called business men-seldom arrive at high executive positions. After all, we must remember that engineers are not very numerous as compared with the occupations just mentioned and therefore a lesser number reaching high executive positions stated numerically might be a larger number stated as a percentage. We all know there must be throughout the United States say three doctors to one engineer, but I don't think that even numerically there are as many doctors in high executive positions as engineers, and it is a fortunate thing for the country that doctors as a class are so busily engaged in alleviating sickness and suffering and in the advancement of medical science that they do not aim particularly for high executive positions.

Jan 1, 1926

By E. W. Johnson, M. L. Hill

Cold working of iron-carbon alloys was found to increase greatly the hydrogen solubility and to decrease the diffusivity at temperatures up to 400° C. These effects are increasing functions of both the carbon content and the degree of deformation. The hydrogen behavior is consistent with the idea that cotd working creates "traps", which are concluded to be microcracks in which the hydrogen is chemisorbed. Hydrogen embrittlement is explained by the Petch theory of metal crack surface energy loss due to hydrogen adsorption. HYDROGEN embrittlement of steel has been studied for many years and has been the subject of an extensive literature, but the mechanism of the effect has not been completely understood. The embrittlement is unusual in that the ductility loss is not accompanied by an increase of the yield strength, being primarily a decrease of the fracture strength alone. The loss of fracture strength is usually most severe in the temperature range between 0°and 100°C. Here the solubility of hydrogen in the iron lattice at ordinary H2 pressures is extremely low while the diffusivity is still quite high. From the relationships between the ductility and the hydrogen content, test temperature and strain rate, it is apparent that the hydrogen atoms causing the ductility loss difbse to and concentrate in small regions of the metal which are especially susceptible to the initiation and propagation of fracture. This hydrogen segregation apparently occurs after plastic straining has begun. Below 0°C the ductility loss persists only at low strain rates in confirmation of the view that the embrittlement is diffusion .controlled. The tendency of the embrittlement to disappear above 100°C can be explained by the increasing lattice solubility of hydrogen with rising temperature. A common view of hydrogen embrittlement of steel is that the hydrogen initially dissolved in the metal lattice diffuses to structural discontinuities and there precipitates as H2 gas at very high pressures which assist the external stress in causing premature failure.1,2 The idea of a high H2 pressure in equilibrium with ordinary amounts of hydrogen in steel at room temperature is due to observations of hydrogen behavior in fully annealed material, for which the Sieverts' law constant relating solute concentration to H2 pressure is extremely small. Hydrogen-embrittled steel, however, is always plastically deformed to some extent, and therefore it is important that hydrogen embrittlement be explained primarily in terms of hydrogen behavior in plastically deformed material. Such an explanation is attempted in this paper. Previous studies of hydrogen in cold-worked steel have shown that both the solubility and the diffusion rate are significantly chaned when the steel is cold worked. Darken and Smith discovered that the amount of hydrogen absorbed from acid by cold-rolled steel at 35°C is many times greater than that absorbed by hot-rolled steel. They found also that the hydrogen permeability of the steel is unaffected by cold working. Keeler and Davis4 confirmed the high apparent solubility of hydrogen in cold-worked iron-carbon alloys at temperatures up to and even beyond the recrystallization temperature. They also found that this solubility increase accompanying cold work is a sensitive function of the carbon content, being absent when no carbon is present. The present experimental study was undertaken primarily to obtain an improved understanding of the behavior of hydrogen in cold-worked steel. Data were obtained on the effects of temperature, H, pressure, carbon content, and degree of cold work on the hydrogen solubility and diffusivity in iron-carbon alloys. These data have been helpful in elucidating the nature of the cold-worked steel structure as well as in providing information on the mechanism of hydrogen embrittlement of steel. EXPERIMENTAL Cylindrical specimens for hydrogen absorption and diffusion rate measurements were prepared from three iron-carbon binary alloys and a commercial SAE 1010 steel. The iron-carbon alloys were prepared by vacuum melting electrolytic iron with graphite in a magnesia crucible. The alloys were cast in vacuum as 2 1/2-in. sq ingots weighing about 20 lb each. The ingots were hot rolled (above 1900°F) to 5/8-in.-diam round bars and then cooled in air to room temperature. The resulting metallographic structure consisted of islands of fine pearlite surrounded by free ferrite. Chemical analyses of the materials are given in Table I. The 5/8-in. diam bars were turned to diameters such that cold reduction to the desired final specimen diameters would result in either 30 or 60 pct reduction in area (RA). The machined bars were then cold worked by swaging at room temperature

Jan 1, 1960

By Donald L. Colwell

THIS is a metallurgical war. More than ever before, the mechanized forces and the air-borne warfare are deciding campaigns. Both of these are primarily dependent upon metals. There are two ways of increasing the effective supply of these metals when the demand is greater than the total over-all supply. The American custom, when a shortage of anything develops, is to get more. In the case of some nonferrous metals this has been done. For example, our potential peak output of magnesium will be almost one hundred times the prewar production. Output of aluminun has also been tremendously increased, and production of other metals is being stimulated by every possible means. Our enemies, however, have another successful method of increasing the effective supply of a material, and that is, to eliminate entirely all nonessential uses, and also to use, in essential applications, alternate materials wherever possible. Sometimes, ersatz material is inferior to the original, and consequently does not do the job as well. Often, however, it has been found superior, and many substitute items are now being used both by industry and by the military which will continue even when the original material again becomes available.

Jan 1, 1943

The following list comprises the names of those persons who became. members during the period Oct. 10, 1919, to Nov. 10, 1919. ABELL, 0. J., Pres. & Treas., Abell-Howe Co., 332 South Michigan Ave.; Chicago, Ill. ADAMI, ARTHUR E., Asst. Prof. of Min. Engrg., Montana State School of Mines,Butte, Mont. BASSETT, R. H Chief Engr., Hanna Ore Min. Co., Hibbing, Minn. BOZA, HECTOR J., Cons. Engr., Boza Aizcorbe Hermanos, Box 106, Lima, Peru. BROWN, HAROLD P., Cons. Concrete Engr 120 Liberty St., New York, N. Y. BUCHANAN, W. A Mgr., Meteor Mine, Slocan City, B. C., Canada. CAMERON, JAMES A Supt., Ellsworth Collieries Co., Ellsworth Pa. CARPENTER, CRANSTON HOWE, Electro-Met. Engr., General Engrg. Division, Westinghouse Electric & Mfg. Co., East Pittsburgh, Pa. CASTLETON, GEORGE T Assayer, Custom Office, Box 122, Eureka, Utah. CHAFFIN, C. E., Eastern Mgr., General Engineering Co., 120 Broadway, New York-, N. Y. CLARK, WALTER R., Wks. Mgr., Bridgeport Brass Co., 1875 Park Ave., Bridgeport, Conn. CLARKE, ERNEST E., Min. Engr., Vinegar Hill Zinc Co., 419 S. Court St., Platteville, Wis. COOLIDGE, E. B., Mgr., Spotted Horse Mine, St. Paul Montana Min. Co., Maiden, Mont. CORTELYOU, ARTHUR P., Resident Mgr., Potrero Min Co. Mocorito, Sinaloa, Mexico. COTTINGHAM, KENNETH, Pet. Engr., Halter & Robitaille Delmonico Bldg.,Fifth Ave. & 44th St., New York, N. Y. CREW, J. A Mgr., Research Dept., Pittsburgh Steel Co., Monessen, Pa. CUMMINGS, LISTER M., Efficiency Engr., Copper Queen Branch, Phelps-Dodge Corpn., Box 1539, Bisbee, Ariz. DANFORTH, GEORGE L., JR., Asst. Gen'l Supt., Illinois Steel Co., South Works, South Chicago, Ill.

Jan 12, 1919

By N. A. MacLeod

Ball wear in wet grinding mills has been the subject of considerable discussion in the last few years. Its importance to millmen is obvious in view of the fact that ball wear may cost from 2 to 4 per ton of ore for the more fortunate operators and many times this cost when a refractory ore must be reduced to a fine state of comminution. Consequently, any factual information that may be obtained on the nature of ball wear may be applied to introduce changes leading to lower ball consumption and therefore also to lower costs. In 1940, while employed with the Britannia Mining and Smelting Co., Britannia Beach, B.C., I had occasion to investigate factors that might affect ball consumption. We performed a number of tests, which will be briefly described. These tests originated as a result of changing from a 3½-in. ball to a 2-in. ball of different type of manufacture and were motivated by the desire to obtain the best possible type of 2-in. ball. Our testing was helped by the fact that the company operated a one-ton electric furnace, so that it was quite easy to make steel changes. It should be emphasized at the beginning that these tests produced results that in their general application to milling should be interpreted qualitatively rather than quantitatively. As will be evident in the description of the method used in testing, the balls were subjected to an intermittent batch grinding treatment, which may have produced results in rate of steel wear that may not have an accurate correlation with steel consumption in full scale mill operation. However, with this bed and rather arbitrary method of testing, results were obtained that may be of some interest and may stimulate further work on this subject. Unfortunately, owing to pressure of war work, our tests, which we had intended to repeat on a continuous grinding operation, had to be discontinued. Method of Testing Tests Were made in a Small cylindrical mill, rotating at 72 r.P.m. Internal dimensions of the mill were 10½-in. dia. by 9 in. The cylindrical inner surface was lined with rubber and the two ends were formed by steel plates. A charge of 2000 grams dry feed and 2000 C.C. of water was added evev 2 hr., the mill being drained of pulp before the addition of each charge, by tilting and sluicing with water. The mill was run On afternoon and night shift for daily periods of about 15 hr. total grinding time, and each test lasted from 60 to 150 hr. This batch method of testing involved a higher average pulp temperature in the mill, which undoubtedly affected comparative results in Some of the tests. Hardness oF Ball vs. Wear In these tests, special "eutectoid" steel balls were used, some of which were chill-Cut and quenched, some sand-cast and quenched, and some sand-cast and annealed to a dead soft condition. The results obtained, using as mill feed an ore containing considerable free quartz and

Jan 1, 1947

By N. A. MacLeod

Ball wear in wet grinding mills has been the subject of considerable discussion in the last few years. Its importance to millmen is obvious in view of the fact that ball wear may cost from 2 to 4 per ton of ore for the more fortunate operators and many times this cost when a refractory ore must be reduced to a fine state of comminution. Consequently, any factual information that may be obtained on the nature of ball wear may be applied to introduce changes leading to lower ball consumption and therefore also to lower costs. In 1940, while employed with the Britannia Mining and Smelting Co., Britannia Beach, B.C., I had occasion to investigate factors that might affect ball consumption. We performed a number of tests, which will be briefly described. These tests originated as a result of changing from a 3½-in. ball to a 2-in. ball of different type of manufacture and were motivated by the desire to obtain the best possible type of 2-in. ball. Our testing was helped by the fact that the company operated a one-ton electric furnace, so that it was quite easy to make steel changes. It should be emphasized at the beginning that these tests produced results that in their general application to milling should be interpreted qualitatively rather than quantitatively. As will be evident in the description of the method used in testing, the balls were subjected to an intermittent batch grinding treatment, which may have produced results in rate of steel wear that may not have an accurate correlation with steel consumption in full scale mill operation. However, with this bed and rather arbitrary method of testing, results were obtained that may be of some interest and may stimulate further work on this subject. Unfortunately, owing to pressure of war work, our tests, which we had intended to repeat on a continuous grinding operation, had to be discontinued. Method of Testing Tests Were made in a Small cylindrical mill, rotating at 72 r.P.m. Internal dimensions of the mill were 10½-in. dia. by 9 in. The cylindrical inner surface was lined with rubber and the two ends were formed by steel plates. A charge of 2000 grams dry feed and 2000 C.C. of water was added evev 2 hr., the mill being drained of pulp before the addition of each charge, by tilting and sluicing with water. The mill was run On afternoon and night shift for daily periods of about 15 hr. total grinding time, and each test lasted from 60 to 150 hr. This batch method of testing involved a higher average pulp temperature in the mill, which undoubtedly affected comparative results in Some of the tests. Hardness oF Ball vs. Wear In these tests, special "eutectoid" steel balls were used, some of which were chill-Cut and quenched, some sand-cast and quenched, and some sand-cast and annealed to a dead soft condition. The results obtained, using as mill feed an ore containing considerable free quartz and

Jan 1, 1947

By Edward W. Parker

IF one is to place any credence at all in the reports published in the daily press, the subject of conservation has been a very lively topic of conversation during the past 60 days, and it does not appear that the temperature of the summer months has been in any way moderated by the discussion. It is a subject in which we are all vitally interested and to which, so far as our mineral resources are concerned, both the Institute and the Geological Survey have liberally contributed. The report of the National Conservation Commission, appointed by President Roosevelt, contains a series of papers on the conservation of mineral resources, all of which were prepared by members of the Geological Survey and were compiled largely from information previously collected by that Federal bureau in the performance of its regular duties. It is not the purpose of this paper to reiterate in extenso any of the material already published. The contributions of the Survey officials to the Commission's report have been published in a separate document as Bulletin No. 394. This docunient is for free distribution and may be obtained upon application to the Director of the Survey. In the preparation of this paper I desire merely to make a few suggestions regarding the possible necessity of some restraint upon or control of one branch of the mining industry with which I have been somewhat closely associated for the past 20 years-that of coal. Most of the members of the Institute are cognizant of the suits brought by the government against the anthracite-operators in Pennsylvania, or the combination of interests commonly known as the ? hard-coal trust." No defense of any illegal combination in restraint of trade is intended, but there are some facts which should not be lost sight of, and unfortu-\

Nov 1, 1909

By J. Washburn, R. Drouard, E. R. Parker

Temperature dependence of the rate of recovery in zinc single crystals after a simple shear deformation at low temperature was investigated. Some tentative suggestions regarding the annealed and strain-hardened states of a crystal are discussed. RECOVERY may be defined as the gradual return of the mechanical and physical properties of strain-hardened metal to those characteristic of the annealed material; an increase in temperature increases the rate of recovery. The annealing process in strain-hardened polycrystalline metals is complicated by the inhomogeneity of strain which always exists in aggregates. Polygonization in bent regions of the crystals and growth of new almost strain-free grains starting at points of severe local distortion1-:' make it almost impossible to isolate and study the recovery process. Homogeneously strained single crystals, however, do not polygonize or re-crystallize and hence they can be used advantageously to study recovery. In such crystals strain hardening is completely removed by recovery alone. Since recovery is a process whereby certain lattice disturbances introduced by plastic flow are gradually reduced, a knowledge of the rate and temperature dependence of this process for various conditions of prestrain might be helpful in formulating a model of the strain-hardened state. For simplicity it seemed desirable to limit the type of prestrain to the simplest obtainable, i.e., simple shear strain. In the experiments to be described, recovery was studied by observing changes in the stress-strain curve of prestrained zinc single crystals held for various times at temperatures above that employed for straining. Single crystals were grown from the melt by a modified Bridgeman technique from Horse Head Special zinc 99.99 pct pure, and from spectrographically pure zinc 99.999 pct pure. They were grown as 1 in. diameter spheres and acid-machined' to the final specimen contour. The test section was a cylinder about 1/8 in. high and 3/4 in. in diameter. The conical sections adjacent to the test section were cemented into the grips so the load could be transmitted to the crystal as uniformly as possible. The specimens were oriented so that in testing the maximum shear stress was applied along one of the slip directions, [2110], in the (0001) plane. Details of the production and testing of such specimens have been presented.' Each test was carried out according to the following schedule: 1—The crystal was strained at — 50°C until it reached a maximum shear stress, ,,,. The strain rate was approximately 5 pct per min in all cases. 2—After straining, the crystal was unloaded before the temperature was changed. Unloading required about 3 min. 3—The temperature of the specimen was then increased from — 50°C to the temperature, T, of recovery. This change in temperature was completed in a time of less than 2 min. The specimen remained at temperature, T, for a time, t, which differed for the various specimens. 4—Thereafter the temperature was again reduced to — 50 °C in approximately 3 min. 5—While at —50°C, the stress-strain curve after recovery was obtained. 6—The specimen was then unloaded and annealed for 1 hr at 375 °C in a helium atmosphere to bring about complete recovery. Cooling to room temperature after anneal required 90 min. 7—The same crystal could be re-used for another test because the plastic properties after annealing closely duplicated those of the original crystal. The specimen was immersed during the test in a bath of methyl alcohol which, through a system of tubes, could be pumped through either of two heat exchangers to regulate the temperature; this was accomplished by circulating the liquid through coils immersed in a bath of acetone and dry ice for cooling or in a bath of warm water for heating. Test temperatures were thus maintained constant within ±1°C. The — 50°C temperature was low enough so that no measurable recovery occurred during unloading and reloading. The stress-strain curve continued after recovery along a path below, but approximately parallel to, the path of a curve obtained in an uninterrupted test. Fig. 1 shows some of the results from a specimen of 99.999 pct Zn. The amount of downward displacement of the curve due to recovery was a

Jan 1, 1954

By Dozier Fircley

SOME nonmetallic minerals and their products, such as portland cement, common brick and hollow tile, sand, gravel, crushed rock, vitrified salt-glaze clay pipe, and the like, are a necessity in every community. They are mineral in nature but the establishment of plants for their production is usually a local and elementary problem. Yet it is probable that an economic study of the problem in every locality will show that such nonmetallic mineral commodities are not always obtained in the most economical way, or in the best quality. Other nonmetallic minerals are of such value that they may be shipped for long distances and sold in sufficient quantities to establish prosperous commercial ventures. Among these are phosphates, barium compounds, borates, nitrogen compounds, magnesium compounds, sulfur, asbestos, and potash. Success in marketing such products depends on quality, production cost, transportation, and similar conditions.

Jan 1, 1932

By Edward P. Barrett

DURING the past few years numerous references have been made in the technical press and Bureau of Mines Bulletin 270 to sponge iron' and so-called "direct metal" processes. The idea has been prevalent that sponge iron and "direct metals" are cheap commodities. In many instances it has been proposed that these processes be used to treat low-grade ores, utilizing low-grade coals as reducing agents. It is questionable whether or not high-grade sponge iron can be made from low-grade materials. Particles contain¬ing iron oxide and gangue become, upon almost complete deoxidation, particles containing metallic' iron and gangue. The possibility of mechanically separating the metallic iron from the gangue in these particles depends . on the physical characteristics of the particular ore under treatment. Some ores, in which the minerals constituting the gangue break free from the iron oxide upon crushing, may be concentrated magnetically after the iron oxides have been reduced to metal. The finely disseminated ores are least amenable to concentration. In general, high-grade sponge iron can only be made from high-grade raw materials. Sponge iron containing small amounts of sulfur can only be made from raw materials containing small amounts of sulfur or by

Jan 1, 1930

By L. R. Jackson, W. T. Lankford, K. F. Smith

ComMercial steel sheet is prepared by a combination of hot and cold rolling and annealing. This treatment usually results in more or less pronounced anisotropy. The anisotropy may manifest itself both as preferred orientation and in the manner in which impurities, segregations, and the like, are aligned in the sheet. The type of preferred orientation and the organization of impurities or segregations may affect the elastic moduli, the yield strength, the tensile strength, and almost always the amount of ductility in different directions. In any case, the most important directions concerned in the anisotropy are along the rolling direction, along the width direction, and along the thickness direction. Considerable data exist on the anisot-ropy of sheet steel as demonstrated by conventional tensile tests; however, few attempts have been made to measure the constants of plastic anisotropy and use them to describe the flow of anisotropic sheet under combined stresses. In this paper, evidence is presented indicating that plastic flow in anisotropic sheet can be described by the shear-strain energy flow theory provided that the anisotropy is properly taken into account. Materials Used in the Investigation Table I lists the sheet materials used in this investigation and describes the condition in which materials were tested. Direction, of Tests and Test Methods Two types of tests were run—tensile tests and hydraulic-bulge tests. Characteristic parameters of anisotropy were determined from the tension tests by methods which will be described later. In all cases, the tensile test pieces were cut from the same quarter line and adjacent to the bulge test pieces in the sheet in order to minimize

Jan 1, 1949

By Charles Prasky

ABOUT five years ago the Bureau of Mines began a study, at Minneapolis, of the various methods for beneficiating the low-grade manganese deposits of the Cuyuna range. Several samples of green carbonate slate from the Cuyuna range, containing about 7 pct Mn and about 28 pct Fe, were obtained for this study. The component minerals in the carbonate slate formation were so intimately associated that mineral dressing methods were not suitable for concentrating manganese to a ferrograde product. Although upgrading of manganese and iron minerals has been effected by flotation methods, it appears that manganese cannot be separated from iron except by chemical means. Because the flotation studies at Minneapolis were carried out simultaneously with the hydrometallurgical studies, only crude slate was available for process testing. An important economic consideration in selecting any one of the several chemical methods proposed for recovering ferrograde manganese is the availability of the chemical reagent. Fortunately, large tonnages of sulfur are available on the Cuyuna range in low-grade pyrite and pyrrhotite deposits that are readily concentrated by flotation to a suitable feed for a sulfide roasting furnace as indicated by a Bureau of Mines investigation in 195 0-1951.1 The roasted residue from the sulfide concentrates is a potential source of marketable iron oxide. Therefore, if these sulfide deposits were employed in recovering manganese, utilization of two heretofore unused mineral deposits would be accomplished. Laboratory investigations of several proposed leaching processes were made as a preliminary step in the investigation of hydrometallurgical methods for the treatment of Cuyuna carbonate slate using sulfur as a chemical reagent. From results obtained in the laboratory tests, these leaching processes did not appear entirely suitable for treating Cuyuna carbonate slate. The method developed at the North Central Experiment Station and selected for a more intensive pilot-plant investigation has been termed the differential high-temperature sulfatizing process. Essentially, this sulfatizing process consists of the following steps, described in the order in which the small-scale pilot-plant investigations were made. The first and perhaps most significant step in the process consists of a sulfate roast. Carbonate slate is roasted in an atmosphere of sulfur dioxide gas and air. The overall chemical reaction for converting manganese carbonate to a sulfate at a high temperature in a sulfur dioxide atmosphere follows MnCO8 + SO2 + 1/2 0, = MnSO4 + CO2 (H077°O = —64,180 cal per g mol) .' The need for concentrated sulfuric acid is avoided. Fine grinding is not essential. Removal of carbon dioxide from the slate during roasting produces a more porous structure and permits easier permeation by the sulfatizing gas mixture. The temperature limits for this conversion of manganese have been established as 600" and 850°C. Iron sulfate is unstable and is not formed at these temperatures; phosphorus is not converted to a water-soluble form; and polythionates are not formed. The second step in the process consists simply of a water leach of the sulfatized product. Manganese sulfate in the sulfatized product is dissolved in water. Iron, phosphorus, and calcium remain in the leach residue as water-insoluble products. The third and final step consists of the recovery of ferrograde manganese oxide from manganese sulfate leach solution. Water is evaporated from the leach solution, and impure monohydrate crystals of manganese sulfate are recovered. The moist crystals are formed into pellets or extrusions and thermally decomposed to produce a ferrograde manganese

Jan 1, 1958

By J. M. Eldridge, P. Balk

Phosphosilicate glass films were formed, by reacting gaseous P2O5 with SiO2, over a large range of temperature (800° to 1200°C) and gas phase composition (nearly two orders of magnitude of effective P2Ospressure). The film compositions generally corresponded with the liquidus curve, delineating the maximum solubility of the tridymite Phase of SiO 2 in phosphosilicate liquid solution at the temperature of film formation. It is shown that the P2O5 concentration of the phosphosilicate liquid film tends to decrease by reaction with the underlying SiO 2 layer until the liquidus curve is reached. The validity of the thermodynamic argument used in this explanation is supported by the results of a determination of the composition of borosili-cute films, prepared by reacting gaseous B2O3 with SiO2 at different temperatures. The kinetics of phosphosilicate film formation were described by a model predicated on a steady-state diffusion of P2O5 through the film. UNDERSTANDING of the processes leading to formation of phosphosilicate and borosilicate glasses is of great importance for producing passivating layers on FET devices. Passivating films with optimum characteristics are preferably formed in a separate step, independent of the doping of the semiconductor.' The results of an investigation carried out to gain improved insight into the mechanism of glass formation are presented in this paper. It would be expected that application of the known Pz05-Si02 and B 2 O 3-SiO2 phase diagrams should be useful in extending understanding of the glass-forming processes. However, the question of the propriety of treating thermally grown SiO2 in these binary oxide systems by the methods of equilibrium thermodynamics must be considered when this application is attempted. Although Sah et a1.' and Allen et al. 3 investigated the kinetics of formation of phosphosilicate glass (PSG), they failed to adequately relate their diffusion models to the occurrence of experimentally observed phases in the PSG/SiO 2/Si system. Horuichi and yamaguchi4 investigated the diffusion of boron through an oxide layer and described their results in terms of a model similar to that of Sah and coworkers. More recently, Kooi 5 and Snow and Deal6 reported the compositions of PSG films formed by depositing P2 O 5 onto SiO2. These compositions apparently coincide with those at the liquidus curve delineating the maximum solubility of crystalline SiO2 in phosphosilicate liquid solutions. These authors did not discuss the thermodynamic implications of their results on the structure of thermally grown SiO2 films. The structure of thermally grown Sio2 films and that of vitreous silica are generally thought to be quite similar. Since the solubility of a substance depends on its structure, it is relevant that the solubility of vitreous silica in water7 is highly reproducible, like the solubility of thermally grown SiOz in phosphosilicate liquid. Furthermore, the vitreous silica-water system appears to be in true thermodynamic equilibrium (viz., the same solubility value can be approached from both supersaturated and under-saturated solutions). Sosman7 suggested that a type of two-dimensional lattice may form at the silica/solution interface, resulting in the observed solubility behavior that is characteristic of a crystalline solid. An alternative explanation may be that vitreous silica has a microcrystalline grain structure. Other investigators have suggested that vitreous silica has essentially the structure of B cristobalite,' or is composed of microcrystals of p tridymite or cristobalite, or a mixture of both. Presumably the grain size would be sufficiently large to minimize any appreciable contribution of the grain boundaries to the solubility of the crystalline matrix. The present investigation was carried out to clarify the significance of the boundaries in the Pa,-SiO, and B2O3-SiO2 Systems in determining PSG and BSG (borosilicate) film compositions. Furthermore, the kinetic data for PSG film formation were extended, using a wider range of formation parameters than were previously reported. One model describing the kinetics of film formation will be presented that is compatible with the thermodynamics of the Pa5-Si02 system. EXPERIMENTAL PROCEDURE Glass Film Preparation. SiO2 films (1000 to 8000A thick) were obtained by oxidation of silicon substrates in dry O2 at 1100°C. PSG and BSG films were prepared by exposing these layers to gaseous oxides obtained by reacting high-purity POC13 and BBr3, respectively, with O2. A double-columned saturator was used to ensure complete saturation of the N 2 carrier

Jan 1, 1969

By Alexandre Pourcel

The phenomena of liquation in steel or iron ingots of all sizes, but naturally to greatest extent in the heaviest ingots, have been noticed ever since the commencement on a large scale of the Besse mer and open-hearth manufactures; but they have been studied with care during the last few years only. The English and the Ameri cans were the first to publish the results of investigation upon phe nomena of this clam, to which they have given the name of segregation. Historical. Passing by that which has been written concerning the segregation observed in gray pig-iron, of which instances were given by Karsten, we shall confine ourselves here to that which is known of this subject with exclusive reference to ingot steel and iron. Mr. H. M. Howe, of Boston, in his Metallurgy of Steel, the most complete and well-arranged treatise upon steel, gives a resume of observations, with the results of numerous analyses, bearing upon the phenomena of segregation. According to Tchernoff (with whom we discussed this question at length in 1878, in connection with the cast-steel plates of large dimensions designed for the Italian fleet, which we showed him at Terre-Noire), Kalakoutsky called attention in 1866 to the lack of homogeneity in Bessemer ingots, especially when cast in sand. Our own attention had been called to the phenomena of liquation in 1868 by a somewhat surprising fact which appeared in almost every one of a number of steel-rail ingots coming from the works of Messrs. Pierre and Emile Martin at Sireuil, to be rolled at TerreNoire. In the heating or in the first groove of the rolls, a slice of from 6 to 10 centimeters (2.4 to 3.9 inches) separated itself from the head of each ingot. As a general consequence, the section of

Jan 1, 1894