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By Arthur C. Forsyth, R. L. Dowdell

A search through the available literature shows that the cobalt-nickel-silicon system has not been systematically studied. This seems rather odd because all three elements are fairly abundant and have better than average corrosion resistance; however, they have high melting points, which makes experimental work difficult. Cobalt and nickel form a continuous series of solid solutions and each metal dissolves about 7.5 per cent silicon. Many ternary alloys have been studied and the results have been published in a great many different ways, but to present such data in a short but clear and understandable manner is still a problem. The following pages describe the results of the study of 76 alloys from which the partial ternary diagram (Fig. 1) of the cobalt-nickel-silicon system has been drawn. The alloys were chosen according to the plan in Fig. la by taking definite ratios of cobalt and nickel, such as 70 Ni, 30 Co or 40 Ni, 60 Co, and adding silicon in various percentages. Each section was studied in detail by means of thermal analysis and microscopic examination, but only two of these detailed sections were thought necessary in the point perspective drawing to give a comprehensive picture of the liquidus, solidus and solid transformations that take place over the temperature ranges studied. Complete thermal analyses and microscopic data are given in Table 1. Experimental Procedure The alloys were prepared from metals of commercial purity, as follows: electrolytic nickel 99.60 + 0.35 Co; chemically purified silicon 99.79 per cent plus impurities of Fe 0.027, A1 0.008, Ca 0.014, C 0.004, N² 0.10; and cobalt 98.82 per cent plus impurities of Ni 0.42, Fe 0.12, CaO 0.27, S 0.012, Mn 0.10 and SiO² 0.15. It should be noted that the largest impurity in cobalt is nickel, one of the alloying elements. The alloys were melted in a small Ajax induction furnace, the nickel and cobalt being melted first because of their better ferromagnetic

Jan 1, 1940

By Harry L. Washburn, Robert L. Llewellyn, W. J. Halvorsen

Many of the problems that occur in the preparation plant originate from practices in the mine. Impurities in raw coal can be in the seam itself or from extraneous material taken in mining from the roof or bottom. In the case of underground mines, the choice of mining equipment will affect the size consist and the amount of extraneous material included with the coal. Also, governmental regulations concerning the degree of rock dusting, gobbing underground, and cleanup have increased the dirt in raw coal. Sulfur dioxide emission standards, on the other hand, are pressuring the coal industry to clean coal more thoroughly. Coal supplied for coking purposes is nearly all upgraded by washing, while for the largest market, electric power generation, a high proportion is shipped as a raw product with processing, in whole or in part, only necessary when excess impurities are mined with the coal. This chapter will deal primarily with plants that process or wash coal to some extent (Fig. 1) and only incidentally with mines shipping raw run-of-mine coal crushed to a top size of, usually, 51 to 102 mm (2 to 4 in.), with little, if any, other treatment. JUSTIFICATION FOR COAL PREPARATION During the past decade, major changes have occurred affecting the market, profit, and long-range planning of the coal industry. Mining companies have become "partners" with consumers at many new and some old mines, both for steam and metallurgical coals. Coal properties have become "assigned" tonnages at mutually agreed upon conditions and prices. Lower unit-train tariffs have been instrumental in helping coal markets to compete against oil and nuclear energy. Coal prices for power plants are still on a Btu (British thermal unit)

Jan 1, 1981

By W. C. Ellis

NONFERROUS alloys upon which desirable properties can be conferred by heat treatment are becoming of increasing industrial importance. The alloys of copper with a constituent which has a solubility varying with temperature are materials of this character. Some of the constituents which are effective in producing a change in the mechanical properties of these alloys upon heat treatment are, according to Corson,1 nickel and silicon, iron and silicon, cobalt and silicon, and chromium and silicon. In addition to these elements, Gregg2 states that the combination of beryllium and silicon is effective in producing age-hardening characteristics in copper. The effect of these elements, however, as dispersion-hardening constituents in the copper alpha solid solutions does not seem to have been studied in any considerable detail. This paper deals with the heat treatment and properties of three alpha brasses containing 3 per cent. of nickel plus silicon in the proportion necessary to form the compound nickel silicide, Ni2Si. Some information of a preliminary nature in regard to the hardening by heat treatment of phosphor bronze containing the same percentages of nickel and silicon is included. The method of hardening the alloys, which is effective in increasing the tensile strength and proportional limit, is similar to that used in, the case of duralumin type aluminum alloys. It consists of a quench from a temperature at which the hardening constituent is in solid solution, followed by an aging at a lower temperature to precipitate the dissolved constituent in a dispersed condition. This results in an increased resistance of the alloy to deformation with an attendant improvement in the tensile properties.

Jan 1, 1929

By L. H. JEFFRIES

In the mining operations of The Canyon Corp., Deadwood. S. D., the use of mucking machines has been of definite advantage. The type used is that which depends upon the traction of the motor-driven wheels to crowd the dipper into the muck pile, while the car in which the muck is received is coupled to the mucker and moves forward or back with it. This general arrangement is entirely satisfactory on a substantially level track. The ores which occur in this district are a replacement of dolomite and the beds are now tilted to an inclination of about 7-1/20. In our operations it is necessary to drive inclines down-hill on this slope, which makes a difficult hand-mucking job even if water were not present. With these facts in mind, an attempt was made to use the mucking machine for driving down the in- cline, but as expected, the traction was insufficient to handle the machine and the necessary car. The means used to correct this condition will perhaps impress most readers as too complicated and cumbersome to effect any economy, but the idea may be of service to some who have a similar condition. After considering several s

Jan 1, 1940

THE slag performs two useful functions. in open-hearth steel-making. First, it is the means of disposal of all the impurities, save carbon, which are removed from the charge materials in refining the steel, so it must be suited to receiving and retaining as much as possible of undesirable elements with minimum loss of iron and useful alloying elements. Second, the slag serves as a buffer between the flame and the bath and transfers oxygen to the metal at a measured pace contrasted with the violent and difficultly controlled oxidation of the bessemer process. At the same time, the slag is a thermal insulator that limits the rate at which heat can be delivered to the metal from the flame, and a heavy slag blanket thereby serves as a brake on production rates. It has been said with justification that the secret of good steel- making is to make a good slag and the steel will take care of itself. In a broad sense, the subject of slag control includes not only the adjustment of the composition of the slag but also of its relative weight in terms of percentage of the metal-bath weight. The slag is made up essentially of: (1) oxides formed by oxidation of silicon, manganese, phosphorus, and iron in the charge, (2) SO2, MnO, MgO, and other oxides charged as such or introduced incidentally with ores or fluxes or by refractory erosion, and (3) lime charged or fed to the heat to neutralize the "acidic" oxides present (SiO2 and P2O5). Obviously, if practically perfect control were possible over the composition of the charge as well as over the oxidation process during the melting period, both slag weight and composition would be very nearly predetermined, and the control problem would be solved. Unfortunately, only a somewhat imperfect control over these factors is possible, so the operator must begin during the lime boil and continue through the refining period to discover and correct departures from the normal pattern of slag development. To do this as the heat progresses, the first helper must be able to make quick estimates of the composition and physical state of develop-

Jan 1, 1951

By Jose Luis de Valle Alonso

Although present electrolytic zinc manufacturing processes are aimed at the direct wet process recovery of the metal, and, with this end in view, several industrial scale patents have been applied for during the last few years, the object of this paper is to enhance the possible metallurgical interest in the conventional recovery of zinc and other metals from leaching residues. Therefore, its main end is the description and discussion of the recovery process of zinc, lead and cadmium from leaching residues. Fundamentally, the process consists of the following: Flotation processing to recover the non-roasted blende still contained in the residues. Pyrometallurgical processing of flotation tails in low-shaft furnaces (kilns) and open-flame rotating furnaces and the ensuing recovery of zinc, lead and cadmium as a mixture of their oxides through volatilization.

Jan 1, 1970

By John Griffen

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

Jan 1, 1943

By D. B. Rushmore, K. A. Pauly

Of primary importance in mine-installations is the hoist, which has a very direct bearing on the successful operation of a mine. Conditions vary greatly with different mines, and especially in different localities. Such factors as depth, incline, the number of levels, permissible or desirable speeds, conditions of ore, etc., are always more or less special in each case. Veins of ore are never exactly duplicated, and the nature of the ground through which shafts are sunk may considerably modify permissible values. As mining-laws are made by the different States, they necessarily vary somewhat, and, even when not fully observed, they introduce factors which qualify the conditions of hoisting men and ore. The amount of timbering required is often of importance as relating to hoisting-conditions. Methods of loading ore affect the time required, as also does the question of the use of cars or skips. Safety-precautions must be very carefully considered, and the number of men in each mine, the number of compartments, and often the method of removing water from the mine, must have careful consideration. While a general discussion of the subject of hoisting is possible, most cases are entirely special, and can be considered only in connection with the peculiar conditions pertaining to that particular installation. The cost of installation of the hoisting-plant may be an appreciable amount, while the cost of raising the ore may be but a small part of the total operating-charge. In many cases, however, the output of the mine is limited by the capacity or the hoist, and the latter thus becomes of the first importance.

Jan 1, 1911

A. Blainey (Ministry of Supply, Atomic Energy Research Establishment. Hnrtoell. England)—With ref- erence to the published work of Hausner et al. on the powder metallurgy of zirconium, it will be of interest to summarize briefly the results of preliminary work we have carried out on this subject at A.E.R.E., Harwell. For the early experiments we used zirconium

Jan 1, 1953

By AIME AIME

NAPOLEON'S dictum that an Army travels on its stomach has not changed in this present war, but the things an Army's stomach calls for would be more than strange to Napoleon. Today one of the main articles of diet for the mechanized army is oil and gasoline, and the chief and most efficient source of 'apply overland is the pipe line. It was a flexible 4-in. pipe line that supplied the voracious appetite of tanks, trucks, jeeps, and planes across the North African desert. and it is the 1800-mile pipe line from Calcutta to Kunming, Yunnan Province in China, the longest in the world, that supplied oil and 100-octane gas for the trucks, tanks, Jeeps, and planes fighting on the Assam-Burma-China front in recent months. Completion of this approximately 1800-mile pipe line to China over rivers that had never been bridged, over hill that towered 9000 ft., and over swamps

Jan 1, 1945

By N. B. Davis

I. Introduction. II. Definition of Plasticity. III. Theories of Plasticity. A. Structure of the clay particles. (1) Fineness of grain. (2) Plate structure. (3) Interlocking particles. (4) Sponge structure of particles. B. Presence of hydrous aluminum silicates. C. Molecular attraction between particles. D. Presence of colloidal gelatinous matter. (1) Review of theory of colloids. (a) Suspension colloids. (b) Emulsion colloids. (2) Experiments. IV. The Formation of Clays. A. Residual clays. B. Transported clays. V. Summary. VI. Conclusion. I. IntRodUction While working with a number of very sticky cracking clays from western Canada the writer became interested in a study of the cause of the excessive plasticity. This led to a review of the rather bulky literature on the subject and the finding that plasticity still remains to be satisfactorily explained. Most of these investigations seem to have been carried on solely from the chemical viewpoint, the geologic aspects having been ignored. In nearly every case, the investigators have worked with the higher-grade clays of low to medium plasticity, such as the kaolins, the excessively plastic ones having generally been neglected, partly because of their limited application, yet the author believes that these are

Jan 1, 1915

By C. A. Zapffe, C.E. Sims

Many hundreds of publications have appeared during the past 78 years that treat the subject of hydrogen in iron and steel.l05 but conclusions regarding the functions of hydrogen in causing some important defects in steel are still unsatisfactory to many; and other hydrogen-caused phenomena yet remain to be identified with this gas. The most widely discussed of these defects is hydrogen embrittlement, but the conception, perhaps the popular one, that embrittlelnent is due to hydride formation aoes not conform to the known facts.l04 The true identity of hydrogen embrittlement seems instead to lie in a mosaic nature of metal crystals, which is a concept not Yet accepted by most metallurgists. A study of hydrogen embrittlement therefore provides new viewpoints in regard to the crystalline substructure of steel.

Jan 1, 1941

By C. E. Sims, C. A. Zapffe

Many hundreds of publications have appeared during the past 78 years that treat the subject of hydrogen in iron and steel.l05 but conclusions regarding the functions of hydrogen in causing some important defects in steel are still unsatisfactory to many; and other hydrogen-caused phenomena yet remain to be identified with this gas. The most widely discussed of these defects is hydrogen embrittlement, but the conception, perhaps the popular one, that embrittlelnent is due to hydride formation aoes not conform to the known facts.l04 The true identity of hydrogen embrittlement seems instead to lie in a mosaic nature of metal crystals, which is a concept not Yet accepted by most metallurgists. A study of hydrogen embrittlement therefore provides new viewpoints in regard to the crystalline substructure of steel.

Jan 1, 1941

By H. G. Moulton

The increasing scale of mining operations over the past decade, particularly in connection with the exploitation of large bodies of comparatively low-grade copper ores, has made necessary the study of the behavior of rock under failure. When extractions of as high as 40,000 tons a day are reached in steam-shovel operations and as high as 20,000 tons per day in underground mining operations, it is evident that excavations soon become of such size that the behavior of the rock will often be dependent on fundamental principles applicable to more or less homogeneous materials under stress, rather than on weathering or local planes of weakness. In the ordinary rock excavations encountered in civil-engineering practice, such as excavations for subways, highways, railroads, etc., rock faces are not carried to depths sufficient to develop any pressures, or consequently any failures, except those due to loose masses resulting from local planes of weakness. When, however, orebodies whose tonnage is measured by hundreds of thousands are to be extracted by steam-shovel operations in open pits, it is necessary to determine if possible in advance the slopes that the sides of the pits will assume, for these slopes influence the shape of the excavations and thereby the amount of ore that may be extracted by the open-pit method. When large orebodies are mined underground at depths of 300 to 500 ft. (91 to 152 m.) by caving methods, the surface subsiding as the ore is withdrawn, it is necessary to determine in advance the outermost limits of fracture in the subsiding surface, for on the delineation of these limits depends the location of surface improvements, mills, smelters, etc. and also the location of development work, such as hoisting shafts, main haulage levels, and all other underground openings that must remain undisturbed during the period of ore extraction. Heretofore, in civil-engineering practice, it has been assumed that earth and rock behave differently in failure. For the calculation of earth pressures, formulas are used in which the assumption is made that earth banks fail by sliding along the slope determined by the frictional resistance of the material. The line of failure and the resulting pressure is held to be dependent on the angle of repose, which is different for varying

Jan 1, 1920

By W. H. Bassett

W H. BASSETT was elected first vice-president at . the executive session of the new Board on Tues- day afternoon. Karl Eilers, H. Foster Bain, Thomas T. Read, and H. A. Maloney were respectively re-elected as treasurer, secretary, assistant secretary and assistant treasurer. The new Executive Committee will consist of W. H. Bassett, Chairman, and Richard Peters, Jr., H. C. Bellinger, E. De Golyer, Edgar Rickard. The Finance Committee will be J. V. W. Reynders, Chair- man, Henry Krumb and H. G. Moulton. George D. Barron was reappointed Chairman of the Admissions Committee, and F. Julius Fohs put in charge of the Papers and Publications Committee.

Jan 1, 1929

By R. L. Templin

THE increasing use of aluminum and its alloys in commercial fields has demanded a better understanding of their machining properties. This fact is exemplified by problems that have arisen in the automotive and airplane industries, but many in other fields might be cited. As pure aluminum and its alloys in their various commercial conditions show appreciable differences in their machining properties, it is not surprising that quite divergent solutions have been offered for the machining problems encountered. However, if the fundamental requirements of the most suitable cutting tools for these metals are understood, these machining problems lend themselves more readily to satisfactory solutions. Since the machining of free cutting brass and mild steel is understood by most persons accustomed to working these metals, it may serve our purpose better to first make a general comparison of the tools more commonly used in machining these metals with the tools most suitable for machining aluminum, then proceed to a more specific discussion of the individual stools.

Jan 1, 1927

Jan 1, 1951

By Marcus Grossmann

THIS paper offers for consideration certain somewhat radical modifications in the iron-carbon diagram, these modifications being the result of the presence of notable amounts of alloying elements. When only small amounts of alloys are present, 'the standard iron-carbon diagram (Fig. 1) can be used with but insignificant changes; when larger amounts of Chromium, Per Cent FIG. 1.-IRON-CARBON DIAGRAM. FIG. 2.-IRON-CHROMIUM DIAGRAM. alloys are present, however, it assumes a distinctly altered appearance. No comment is offered for the present except to call attention to the delta area, A4BM, which represents a region of mixtures of austenite and delta iron, just as area A3SP represents mixtures of austenite and alpha iron.

Jan 12, 1926

By R. G. Bowman

DISCUSSIONS of processes for the manufacture of white lead generally open with the statement that white lead is the oldest chemical pigment known to man. This fact is of more than historical interest; in the light of the present extensive use of white lead, ii indicates that the .compound possesses characteristics that make it unique among white pigments, and superior to all ;in its particular field. A greater variety of processes have been proposed for manufacturing white lead than for any other one chemical compound. Only a few of these processes have come into commercial use, however, and a large part of the present production here and abroad is made by the process used in ancient times. The outstanding disadvantages of the old process are that it is slow and laborious, affords no control of the product, and yields at best an impure material lacking in uniformity. Improved processes, sometimes classed all together as "quick processes," have had as their main object the shortening of the time required. Most of them accomplish this and some have yielded a superior product as well, but only two or three are now in use commercially. For centuries the manufacture and mixing of paints has been treated as an art, and the practice has been much influenced by tradition and precedent. There is a reluctance to abandon old materials for this purpose, and as few new uses for white lead have been developed, the adoption of the quick processes has been slow. The electrolytic production of white lead is not-new, a large number of processes and forms of apparatus have been proposed and patented within the past 25 years, all directed toward the, production of white lead, wholly or in part, by electrolysis. One or two of these processes were tried commercially but proved unsuccessful.

Jan 9, 1925

Nationalization of the coal mining industry in Great Britain was one of the first pieces of major legislation enacted by the post-war Labor Government in 1964. It followed a long period of economic depression with high unemployment and bad industrial relations in the coal mining industry during the 1930's, and shortages of coal during the last war. Upon nationalization, the National Coal Board took over control of the industry in 1947 and so became the biggest single employer of labor in the western world. As well as the coal mines themselves, it assumed responsibility for a great variety of other assets including coke ovens, byproduct plants, land, houses, railways and shipping wharves.

Jan 6, 1964