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By W. C. Ellis, M. E. Fine

INTRODUCTION IN the iron-cobalt system there are several property-composition relationships of theoretical importance. The alloys are ferromagnetic exhibiting a maximum saturation at approximately 33 at. pct cobalt;1 the interatomic distances at room temperature show large positive deviations from Vegard's rule;2 and in the region of 50 at. pct cobalt there is an order-disorder transition which has a large effect on other properties. The thermal expansion data for the system have been reported3,4.5,6 only from room temperature to 100°C, and for this temperature range a minimum in coefficient in the region of 50 at. pct cobalt is well established. 3,4,6 This paper reports the expansion properties in the iron-cobalt system for temperatures from 30 to 850°C, shows the correlation with other physical properties, and proposes an explanation for the interrelation. EXPERIMENTAL PROCEDURE The thermal expansivities of iron-cobalt alloys in 10 pct steps in composition were determined from 30 to about 850°C. The major series of alloys was prepared by induction melting from Armco iron and cobalt rondelles with the addition of about 0.6 wt pct manganese. This series was supplemented by three compositions: high purity electrolytic iron, high purity electrolytic cobalt, and an alloy of 52.1 wt pct cobalt prepared from the high purity electrolytic iron and electrolytic cobalt by vacuum-melting. The compositions of both series of alloys are given in Table I. The specimens for measurement were prepared from the cast ingots by first hot-swaging followed in most instances by cold-swaging to 0.180-in. diam rod. Some alloys in the region of 50 pct cobalt, because of inherent cold-brittleness, were swaged hot to the final diameter. The expansion specimens were approximately 2 ½ in. long with flat-ground and polished ends. Before measurement they were annealed in hydrogen for r hr at 900°C. In the apparatus used for the thermal expansivity measurements (Fig I), a modification of that designed by Hidnert and Sweeney,7 the differential expansion between the specimen and vitreous silica was measured by a dial micrometer reading to 0.001 mm. An invar fixture supported the dial gauge, and this fixture, in turn, was connected to a split invar collar which supported the outer silica tube. A pyrex "T" was placed over the outer silica tube and was sealed to the invar collar by Apiezon Q sealing compound. A movable hollow vitreous silica rod which rested on top of the test specimen slid through a flexible rubber diaphragm cemented to the top of the pyrex "T." The specimen rested on a vitreous silica pedestal fused into the outer tube and was kept centered by a silica sleeve. A non-oxidizing atmosphere was obtained by admitting hydrogen into the

Jan 1, 1948

[United Engineering Society WALTER H. ALDRIDGE J. VIPOND DAVIES J. V. N. DORR Engineering Societies Library Board SYDNEY H. BALL ALEXANDER C. HUMPHREYS GEORGE C. STONE JOHN H. JANEWAY Engineering Foundation Board H. M. BOYLSTOX J. VIPOND DAVIES GALEN H. CLEVENGER]

Jan 1, 1928

By M. B. Truehaft

Expectations for coal in the early to mid-1970s prompted the government and industry to pursue research and development programs to increase underground and surface mining coal Productivity and net coal recovery. Several programs concerned advanced surface mining methods for thin seam coal recovery. Three such programs, along with related areas of interest, presented in this paper are: extended depth augering for trench-strip applications; high recovery auger heads for enhanced recovery; and variable wall mining in low cover longwalls. Conceptual development is examined, prototype testing is discussed, and potential operations are considered.

Jan 1, 1985

By CHARLERS R. FETTEE

A slight decrease in drilling activity occurred in the oil fields of western Pennsylvania during 1945 and a considerable decrease in the shallow-gas territory (Upper Devonian or higher). The number of deep tests (Middle Devonian or deeper) completed was two less than in 1944 and these did not open any new reserves of natural gas. Thus far, no commercial oil has been encountered in sands below the Upper Devonian in Pennsylvania. Oil production declined 8 per cent.

Jan 1, 1946

By Paul C. Merritt

The story now unfolding on the Mesabi Range is more than just another chapter in the continuing history of iron mining. It is an epic of foresight, research and pioneering instinct just now culminating in the rapid growth of a new industry hardly more than ten years old. And that growth has been impressive. In the decade that has passed since Reserve Mining Co. blazed a trail as the first successful large- scale commercial taconite operation, the number of plants now existing or soon to be operating has grown to six. From Reserve's initial capacity of 3 million tons of pellets per year, total production capacity on the Range has surged to 31.5 million tons while capital investment has leaped from $300 million in 1955 to almost $1 billion today. During the past year alone, more than $500 million has been committed to these projects, an amount probably greater than that going into any other single mining area in the world. There is more yet to come.

Jan 10, 1965

Jan 1, 1905

By H. H. Smith, G. J. Danek, M. R. Achter

Nickel, Type 316 stainless steel, and copper show decreases in reversed bending fatigue strength with increases in air and oxygen pressure. The leveling off of the log N us log p curve for nickel at 300" and 816°C is discussed in terms of a model in which surface saturation gives rise to a critical pressure. A metallographic study indicated that the effect of environment on crack initiation and growth rates is a function of temperature. It is shown that small amounts of impurities in inert gases may substantially reduce the fatigue strength of nickel. 1n a previous investigation1 of high-temperature bending fatigue in air and in vacuum, reversals in the effect of environment with changes in test conditions were atrributed to a mechanism consisting of two processes acting in competition. One of them, oxidation strengthening, has been demonstrated in a straightforward manner by measuring the rupture strength of a sintered nickel-oxide bond.' The detailed operation of the other process, facilitation of crack propagation by surface absorption of oxygen, is uncertain. Thompson et UZ advanced the possibility that the formation of an oxide layer prevented rewelding of cracks during the compressive part of the cycle, while Wads worth and Hutchings4 further proposed that the reaction of oxygen with atoms at the tip of the crack helped the metal to break there, a possibility which has also been advanced to explain crack formation in creep.5 A difficulty in arriving at a mechanism for this lowering of fatigue strength in air is the inconsistency of some of the data. For example, Wadsworth and Hutchings4 found an approximately linear decrease of log cycles-to-fracture (N) with an increase of log pressure-of-air (p) for copper and aluminum at room temperature, while snowden,' although finding a similar linear dependence for aluminum, observed a stepped curve for lead. Between l0-' and 10"1 torr there is a sharp decrease in the fatigue life of lead with increasing air pressure, but plateaus, signifying no dependence on pressure, are found at higher and lower pressures. If, as discussed elsewhere: these environmental effects arise from the adsorption of gas on crack surfaces, it would be expected that as the pressure is increased a saturation point would be observed, beyond which there is no further effect. To gain further information about the form of the log N vs logp curve, it was decided in the present investigation to repeat this type of measurement at elevated temperature on nickel, copper, and Type 316 stainless steel. An additional object of this program was

Jan 1, 1963

By G. A. Vissac

In the presentation which follows, wash-ability curves, such as are commonly used in making studies preliminary to the cleaning of any coal or to the concentration of any mineral, have been reduced in each instance to a single straight line; thus all the most important characteristics of the coal or mineral are represented in a form more advantageous than that in which such data usually are shown. To obtain consistent results, float-and-sink data must be based on a single definite narrow size range, which may be designated "a coal unit." It will be shown that such units, each embodying a different size range, can be grouped to form what may be termed "a composite coal." A three-dimensional presentation will emerge, which will closely identify the coal, illustrate its characteristics in a new manner and explain many obscure facts. Float-and-sink Tests For the preliminary study of any cleaning or concentration problem, or in the control of any operation, float-and-sink tests must be made. The results of these tests are grouped in tabular form and then illustrated in various systems of curves; but if such a graphic representation is to have the utmost practical value, it must offer at least the following advantages: (I) It must be easier to read than the tabular results, and (2) it must be easy to plot, check and interpolate. The first requirement will be attained by reducing the number of curves to a minimum, and the second by some system of representation that will use only straight lines. Of the many washing curves now in use, only the "recovery curve," often known as the "composite curve"—a somewhat misleading term—will be considered; Any point on the recovery curve will show what percentage of weight of clean coal can be recovered when the mineral is washed at a certain specific gravity. As an example, the tests listed below Fig. I are illustrated in the drawing by a curve obtained by plotting (I) as abscissas the ash content of the coal recovered and (2) as ordinates the corresponding percentage of refuse discarded; but, in general practice, instead of writing down that weight, it is customary to set down its complement, which is the corresponding weight of coal recovered. From this curve can be deduced the information necessary for the solution of most practical problems. New Form of Graphic Presentation The resemblance of the recovery curve ill Fig. 1, or, for that matter, the recovery curve obtained in common practice! to a Power curve is apparent. The general equation of such a curve is Y = axn, where n is negative. Taking logarithms: log y = a + n log x. Using a logarithmic scale, the equation of the recovery curve will be Y = A + bX. On this logarithmic basis! the recovery graph will be a straight line, using the same variables as in Fig. I; namely, the ash con-

Jan 1, 1942

By G. A. Vissac

In the presentation which follows, wash-ability curves, such as are commonly used in making studies preliminary to the cleaning of any coal or to the concentration of any mineral, have been reduced in each instance to a single straight line; thus all the most important characteristics of the coal or mineral are represented in a form more advantageous than that in which such data usually are shown. To obtain consistent results, float-and-sink data must be based on a single definite narrow size range, which may be designated "a coal unit." It will be shown that such units, each embodying a different size range, can be grouped to form what may be termed "a composite coal." A three-dimensional presentation will emerge, which will closely identify the coal, illustrate its characteristics in a new manner and explain many obscure facts. Float-and-sink Tests For the preliminary study of any cleaning or concentration problem, or in the control of any operation, float-and-sink tests must be made. The results of these tests are grouped in tabular form and then illustrated in various systems of curves; but if such a graphic representation is to have the utmost practical value, it must offer at least the following advantages: (I) It must be easier to read than the tabular results, and (2) it must be easy to plot, check and interpolate. The first requirement will be attained by reducing the number of curves to a minimum, and the second by some system of representation that will use only straight lines. Of the many washing curves now in use, only the "recovery curve," often known as the "composite curve"—a somewhat misleading term—will be considered; Any point on the recovery curve will show what percentage of weight of clean coal can be recovered when the mineral is washed at a certain specific gravity. As an example, the tests listed below Fig. I are illustrated in the drawing by a curve obtained by plotting (I) as abscissas the ash content of the coal recovered and (2) as ordinates the corresponding percentage of refuse discarded; but, in general practice, instead of writing down that weight, it is customary to set down its complement, which is the corresponding weight of coal recovered. From this curve can be deduced the information necessary for the solution of most practical problems. New Form of Graphic Presentation The resemblance of the recovery curve ill Fig. 1, or, for that matter, the recovery curve obtained in common practice! to a Power curve is apparent. The general equation of such a curve is Y = axn, where n is negative. Taking logarithms: log y = a + n log x. Using a logarithmic scale, the equation of the recovery curve will be Y = A + bX. On this logarithmic basis! the recovery graph will be a straight line, using the same variables as in Fig. I; namely, the ash con-

Jan 1, 1942

By G. A. Vissac

IN the presentation which follows, washability curves, such as are commonly used in making studies preliminary to the cleaning of any coal or to the concentration of any mineral, have been reduced in each instance to a single straight line; thus all the most important characteristics of the coal or mineral are represented in a form more advantageous than that in which such data usually are shown. To obtain consistent results, float-and-sink data must be based on a single definite narrow size range, which may be designated "a coal unit." It will be shown that such units, each embodying a different size range, can be grouped to form what may be termed "a composite coal." A three-dimensional presentation will emerge, which will closely identify the coal, illustrate its characteristics in a new manner and explain many obscure facts. FLOAT-AND-SINK TESTS For the preliminary study of any cleaning or concentration problem, or in the control of any operation, float-and-sink tests must be made. The results of these tests are grouped in tabular form and then illustrated in various systems of curves; but if such a graphic representation is to have the utmost practical value, it must offer at least the following advantages: (I) It must be easier to read than the tabular results, and (2) it must be easy to plot, check and interpolate. The first requirement will be attained by reducing the number of curves to a minimum, and the second by some system of representation that will use only straight lines. Of the many washing curves now in use, only the "recovery curve," often known as the "composite curve "-a somewhat misleading term-will be considered. Any point on the recovery curve will show what percentage of weight of clean coal can be recovered when the mineral is washed at a certain specific gravity. As an example, the tests listed below Fig. I are illustrated in the drawing by a curve obtained by plotting (I) as abscissas the ash content of the coal recovered and (2) as ordinates the corresponding percentage of refuse discarded; but, in general practice, instead of writing down that weight, it is customary to set down its complement, which is the corresponding weight of coal recovered. From this curve can be deduced the information necessary for the solution of most practical problems. NEW FORM OF GRAPHIC PRESENTATION The resemblance of the recovery curve in Fig. I, or, for that matter, the recovery curve obtained in common practice, to a power curve is apparent. The general equation of such a curve is y = axn where n is negative. Taking logarithms: log y = a + n log x. Using a logarithmic scale, the equation of the recovery curve will be Y = A + bX. On this logarithmic basis, the recovery graph will be a straight line, using the same variables as in Fig. I ; namely, the ash con-

Jan 1, 1942

By T. A. El-Bassyouni, Paul Gordon

Grain-gvowth data in zone-refined aluminum and in dilute alloys of copper with this aluminum have been obtained. The amounts of copper added were from 4 to 400 at. ppm. It was found that in both the unalloyed aluminum and the alloys grain growth was characterized by a high value of n in the isothermal growth equation 6n = Kt The inadvertent presence of 1 at. ppm Fe in the alloys was found to he more potent in slowing growth than the purposely added copper. Possible rationalizations of these observations and their general relevance to the theoretical use of gvain-grozvth data have been discussed. Grain growth data of Winegard and his co-workers' on zone-refined tin and dilute tin alloys were analyzed with some success2 in terms of approximate theoretical equations for boundary migration.2-4 In view of this success, experiments were carried out in an effort to obtain similar data on zone-refined aluminum and on dilute copper-in-aluminum alloys. The results obtained were anomalous in several respects and could not be used to test theory. A discussion of these anomalies is presented here; they have been attributed to impurity effects and serve to emphasize the sensitivity of grain growth in general—and the particularly high sensitivity in aluminum—to impurities. The resulting difficulties in the theoretical use of grain-growth data are also discussed. EXPERIMENTAL DETAILS An aluminum bar was zone-refined and leveled by methods similar to those described previously.' The degree of purity obtained is indicated in Table The data in Table I were determined by mass-spectrographic methods through the courtesy of Mr. Thomas A. Johnson of AIAG Metals, Inc.* Three dilute copper alloys with this aluminum were prepared also by methods described previously.' The alloys contained nominally 4, 40, and 400 at. ppm of Cu, respectively (0.001, 0.01, and 0.1 wt pct). Each material was fabricated by swaging and rolling into a round bar about 1/4 in. in diameter with an annealed penultimate grain size of approximately 0.003 to 0.007 cm. In order to minimize preferred orientation the fabrication was carried out in several steps, each consisting of a reduction of about 40 pct followed by a recrystallization anneal. Annealing temperatures for the grain-growth studies were attained by the use of boiling liquids up to 213°C and molten metal baths at higher temperatures. Temperatures were controlled to within 1°C. Samples for measurements were cylinders about 3/4 in. long and 1/4 in. in diameter cut from the fabricated rods. In the interests of sample economy a single sample was used for the grain-growth measurements at each temperature. Each sample was, thus, annealed for several successive periods of time, the grain size being measured at each annealing period on a transverse surface exposed by

Jan 1, 1965

By J. C. M. Li

A dislocation model is constructed for a cylindrical tilt boundary of which the axis of tilt is parallel to the axis of the cylinder. The strain energy per unit area calculated from this model agrees with thut of an infinite vertical wall of edge dislocations. Based on this model, a dislocation mechanism for the shrinking of such a cylindrical boundary is proposed. The power relation between the grain boundary velocity and the driving force is accounted fm by the stress dependence of dislocation velocity. The activation area for grain boundary motion is found to correlate with that .for Creep in aluminum. In the preceding paper' the velocity of a curved grain boundary is found to be a power function of the driving force, [1] where M is the velocity at unit driving force, y is the grain boundary energy, and p is the radius of curvature. This finding adds another nonlinear rate equation to metallurgical phenomena. While a macroscopic theory for the steady state as just presented2 can be used to understand the shape of the moving boundary, such theory usually does not provide any information about the atomistics of the process. It is attempted in this paper to discuss the nonlinear rate equation in terms of a dislocation mechanism. A DISLOCATION MODEL FOR A CYLINDRICAL TILT BOUNDARY Before a dislocation mechanism can be proposed for the motion of a cylindrical tilt boundary, it is necessary to construct a dislocation model for the boundary. For simplicity, a tilt boundary in a simple cubic lattice will be examined. Although this does not represent the situation in aluminum, it is expected that the general features will be similar. The details of the model in the fcc lattice can be constructed when a refinement of the simple model is called for. A cylindrical low angle tilt boundary in a simple cubic lattice is shown in Fig. 1. Two sets of edge dislocations are needed as shown. A schematic representation is shown in Fig. 2(a). In terms of a continuous distribution of dislocations, the density of dislocations n, of Burgers vector b, in the small segment ds of the grain boundary is Similarly the density of dislocations n, of Burgers vector bz in the same segment ds is where is the tilt angle of the grain boundary. Based on this continuous distribution of dislocations in the grain boundary, it can be shown that the interaction between a small segment of the boundary and the rest of it is zero. Furthermore, the stress produced at any point inside or outside the cylinder is also zero. This shows that the model is acceptable in the sense that the boundary has no long-range stresses. Since the model of continuous distribution of dislocations in the grain boundary does not reveal the interactions among individual dislocations, a discrete dislocation model has to be used for such purpose. For simplicity, an equivalent model is shown in Fig. 3. This arises because the total Burgers vector is, from

Jan 1, 1970

By J. W. Ristori, V. R. Garfias

ONE of the most serious problems now confronting Gel- many-and one that will affect Italy even more seriously if she goes to war against England and France -is that of supplying her navy, mechanized army, and air force as well as her industrial and other needs with the necessary and related products. This problem, serious even now, will become vital should hostilities on a large scale develop.

Jan 1, 1939

By H. A. Guess

A Discussion of the Paper by Mr. H. A. Guess, read at the Atlantic City meeting, February, 1904. MR. JOSEPH P. GAZZAM, Germiston, Transvaal, So. Africa (communication to the Secretary*) :-About fourteen years ago, in southeastern Missouri, I used a method for the wet determination of lead which closely resembles the modified sulphate-chromate method described by Mr. Guess. The principal difference, however, is, that after dissolving the lead chromate in hydrochloric acid, the chromic acid is determined by means of a standard solution of ferrous sulphate. The method, which I believe is still in use in southeastern Missouri, was found to be convenient and accurate for the determination of lead in the ores and various products of the mills and furnaces in that district, but it was never used for complex ores. A number of determinations of lead in mill-tailings were made in the year 1891; a few of these results are given in Table I.

Mar 1, 1905

By Victor Rudenno

Feasibility studies for mining projects traditionally involve in their final stages a lengthy process of repetitive trial and error discounting, in calculating the discounted cash flow rate of return resulting from the respective yearly after-tax cash flows. Also, probability analysis and sensitivity analysis (in particular) require extensive additional calculations with each change of any project parameter . These inefficient repetitive procedures have two unacceptable results: 1. they are not flexible enough to allow ready analysis of dependent parameters , and 2. they require resort to high-capacity centralised computing facilities with their inherent impersonality, rather than a convenient and available desk calculator - a factor of particular importance to top mining management. Such problems can be overcome if the mining project can be represented by a reasonable straightforward mathematical economic model. The most flexible and appropriate model has been found to be one in which a maximum and minimum value for each of n parameters are supplied to a program which determines a large number of systematic combinations of parameter events and then statistically analyses them to determine the resulting coefficients of the model. In this paper the authors discuss the selection of the most appropriate type of model and outline the steps followed in its development and application.

Jan 1, 1977

By Alan M. Bateman

Before World War II we proudly considered that we were the nation of all the world most richly endowed in mineral resources. We knew it was no accident that those countries abundantly supplied with mineral resources became the great manufacturing nations, and the politically and militarily strong ones; and that our own great industrial cities sprang up where coal and iron met. We all reallized, especially we of the mining profession, that the energy of fuels and the solidity of metals spelled industrial growth and in turn industrial might and that other nations came to regard mineral self-sufficiency as one of the chief goalsof economic nationalism.

Jan 1, 1949

By F. C. Noyes

DAME Nature was in a generous mood when she distributed widely over the face of the globe numerous deposits of phosphate rock from which man can make phosphatic festiIizer to replace the phosphate re- moved from the soil by crops. The principal deposits are readily accessible to the world's greatest consuming areas and most of them are such that mining operations can be carried on at relatively low cost. The world's known reserves shown in Table 1 are sufficient to last well over 2000 gears at the present rate of consumption. Before giving a brief outline of the phosphate rock industry of foreign countries let us try to get a picture of the movement of phosphate rock throughout the world in 1938, the last full normal calendar year where it came from and where it was consumed. Table 2 shows the origin and finial destination of world shipments in 1938 by grand divisions. Table 3 (p. 499) shows shipment9 of phosphte rock to each country in Europe. Europe is seen to be by far the world's greatest market and the French North African mines the world's most important producers outside of the U. S. A.

Jan 1, 1944

By R. HAYDEN, H. B. HALLOWELL, H. O. Hofman

THE object of refining copper in the reverberatory furnace is to obtain a metal which will have the highest attainable degree of malleability, ductility and electric conductivity, and present at the same time a level surface when it solidifies in the mold after casting. These desirable physical properties are governed by the character of the impurities and the forms in which they are present, by the amount of cuprous oxide retained by the copper, by the quantity of gas held in solid solution, by the casting-temperature, and by the thickness of the casting. The effects of impurities, of cuprous oxide and of gases upon the mechanical properties of copper have been studied by Hampe in his classical paper "Contributions to the Metallurgy of Copper." The most recent research into the effect of metals upon the electrical conductivity of copper is that of Addicks.2 The influence of cuprous oxide upon the electrical conductivity has been investigated by Walker' and Addicks.4 The absorption of gases has received' attention by Hampe,5 Stahl 6 and Heyn.7 The effects of casting-temperature have been noted by Stahl.8

Mar 1, 1907

By Carl Samans

THE attention of physicists and metallurgists has been directed toward the study and explanation of the deformation textures in metals for the past 15 years. In 1920 N. Uspenski and S. Konobejewski1 were first able to show that the symmetrical X-ray diffraction effects that had been previously reported by E. Hupka2 and others in metal foils were caused by a directed arrangement of the crystallites. Since then, the systematic study of textures resulting from the application of the pure forces of tension or compression to polycrystalline materials hag been supple-mented by many investigations on deformed single crystals, which have greatly added to our knowledge of deformation. However, despite the valuable information secured from these comparative studies only four investigations upon cold-rolled single crystals of any of the face-centered cubic metals have been reported in the literature. This lack of quantita-tive data is especially unfortunate because of the much greater practical significance of rolling textures and their effects in both cold-rolled and annealed materials. This investigation was undertaken for the purpose of specifying the deformation of rolled single crystals in the hope that such information might later facilitate the explanation of polycrystal-line textures.

Jan 1, 1934

By Henry M. Howe

THIS meeting was held at the home of the Institute in the United Engineering Society Building, 29. West 39th St., New York, N. Y., Feb. 18 to 21, 1908. The first session, held in the large auditorium Tuesday evening, Feb. 18, was called to order at 8 p.m. by Prof. Henry M. Howe, Past-President of the Institute, who welcomed the members and guests in a few cordial and well-chosen remarks. The following papers, accompanied by lantern-illustrations, were presented in oral abstract by their authors Swedenborg and Humboldt, by R. W. Raymond, New York, N. Y. Electric Power in Steel Mills, by David B. Rushmore and Karl A. Pauly, Syracuse, N. Y. At the close of the session, an informal reception in the offices of the Institute was tendered to members and guests. The second session, held in Assembly Room No. 1 in the same building, Wednesday, Feb. 19, was called to order at 10 a.m. by Prof. Robert H. Richards, Past-President of the Institute. Before proceeding with the papers on iron and steel, which were scheduled for presentation at this session, Mr. F. E. Junge, a representative of the gas-engine and electric motor industry of Berlin, Germany, gave a short oral discussion of the paper by Mr. Rushmore and Mr. Pauly, Electric Power in Steel Mills. Printed copies of the paper, Uniform Nomenclature of Iron and Steel, were distributed among the members and guests present, and the request was made for a later discussion of this important subject by letter. This paper constitutes the Report of Committee No. 24, of the International Association for Testing Materials, which was presented at the Brussels Congress in 1906. The following paper was presented in oral abstract by the author

Mar 1, 1908