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By M. H. Sommer

MANY attempts have been made to develop a relation between the tensile properties and the deep-stamping qualities of metals com-monly used in deep drawing. These operations are generally performed cold and the metal is always stressed beyond the elastic limit. However, the problem cannot be readily solved without a proper investigation of (1) the relation between actual stress and actual strain in the plastic range and (2) the stresses that are set up in the metal during the process of deep stamping. Much work has been done in recent years to add to our knowledge on plastic deformation of metals and the shortcomings of the ordinary tensile test, particularly in the plastic range, have been sufficiently recognized. It has been widely acknowledged that the local contraction, which appears in a tensile test after the maximum load is reached, is not a general characteristic of the material but is peculiar to this form of testing. The plastic deformation of materials is explained by the slip of their crystals along certain planes and this rearrangement should be similar whether observed in a tensile, compression or torsion test, and if the results of any of these forms of testing show deviations, it must be due to other influences, as for example the local contraction in a tensile test. For this reason the tensile-test curve as obtained from the measurements taken on a tensile-test machine or registered by an autographic device has been supplemented by the so-called "actual stress-strain curve," which is constructed from the observed tensile-test data by eliminating the effect of local contraction and is in complete alignment with the stress-strain values obtained in a compression or torsion test. The actual stress-strain curve shows the increase of actual unit stress in relation to unit elongation beyond the yield point and

Jan 1, 1934

By Arthur F. Colombo, Donald W. Frommer

With the opening of the Tilden mine near Ishpeming, MI, a new era in iron ore beneficiation was begun. A description of a U. S. Bureau of Mines investigation is summarized to illustrate the selective flocculation-deslime-flotation process developed by the Bureau and used at the Tilden concentrator, which is also briefly described. The operating parameters for the selective flocculation-cationic flotation of an oxidized taconite from the Mesabi range are discussed. A water reclamation system using lime and a cationic flocculant was applied to reclaim the effluents from a 900-pound-per-hour flotation pilot plant. About 80 percent of water requirements were recovered, and the calcium content of the reclaimed water was found to be more important than clarity in influencing the selective flocculation and flotation processes. Although reclaimed waters with about 10 ppm calcium registered turbidities of approximately 5,000 ppm SiO2 equivalents, the concentrates produced using these waters contained 64 percent Fe and 55.0 percent SiO2 and had accompanying iron recoveries of 75 percent. Lower grade concentrates resulted from using reclaimed water with higher calcium contents and lower turbidities.

Jan 1, 1976

By H. C. Heard

The review by Professor J. C. Jaeger (Chapter 1) briefly summarizes and discusses a select group of papers by various workers dealing primarily with aspects of fracture in brittle rock materials. Professor Jaeger's treatment is primarily concerned with the correlation of phenomenological and theoretical failure criteria with empirical results from short duration tests at ambient temperatures and generally at low lithostatic and interstitial fluid pressures. As engineering rock mechanics becomes more concerned with new techniques of mineral exploration and production at increasingly greater depths in the crust, it is well to be aware of the effect of the environment -that of the superposed stress field upon the lithostatic and interstitial fluid pressure, the temperature and the duration of the loading upon the failure of rocks either by fracture or flow. All results to be discussed here are from laboratory tests on small homogeneous samples, thus caution should be used in the direct extrapolation of these results to large inhomogeneous rock masses having quite different boundary conditions in the earth. The purpose of this supplement is to briefly point out the major effects of these parameters as examined singly, with all others held constant, and to cite some recent results which apply to the main theme on the brittle failure of rocks. The total stress field imposed upon a small volume of porous and permeable rock in the earth's crust may be thought of as the sum of an applied differential stress, plus a lithostatic pressure, plus an interstitial fluid pressure. The differential stress portion may be completely specified by nine components, six shear and three normal. If the small volume element is in rotational equilibrium, by suitably choosing our coordinate axes we may resolve these nine components into the three principal com-

Jan 1, 1967

By J. P. Zannaras

Referring to the article by R. J. Charles and P. L. de Bruyn, let us assume that W = weight of glass bar; P = weight of hammer; e = total deformation; E = unit of deformation; K = potential stress energy; E = modulus of elasticity; L = length of the bar; 7, = coefficient of inertia; h = height, ft; V = velocity, fps; and a = cross section area. The portion of kinetic energy which is effective in producing stress energy in a fixed bar struck horizontally is given by the formula [ ]

Nov 1, 1956

By Otis M. Clarke

The Eufaula bauxite-kaolin district in southeastern Alabama is an important source of raw material for the refractory industries in the United States. At the present time, five companies are mining and processing bauxite and kaolin from this district and a sixth company is holding substantial reserves. Mining operations are expanding, but finding new ore reserves is a major problem. The Geological Survey of Alabama sponsored geologic research in the Eufaula district to: (1) investigate the

Jan 1, 1973

By E. A. G. Colls

IN all branches of the chemical industry, corrosion plays a very costly part unless it is suitably com-batted, and as a result it is probably correct that chemical and design engineers are more corrosion conscious in the field of chemical industry than in others. Most metals occur in nature in combination with other elements. The refined or reduced state to which man converts them for his use, by removing the combining elements, leaves them in an unstable condition. Therefore in most of the media to which the metals are exposed they are constantly combining with the constituents of their environment, or in other words they are continually being corroded. Similarly, nonmetallic materials are corroded by undergoing chemical change. The rate at which corrosion takes place varies widely from metal to metal and medium to medium. In practically all cases the corrosion of metals in solutions (electrolytes) is electrolytic in nature and the rate of corrosion is dependent on many factors such as temperature, pressure, internal stresses, galvanic action, metal-ion concentration, and so on. In the chemical industry substances must be handled which are particularly corrosive to materials of construction. At the chemical plants of The Consolidated Mining and Smelting Co. of Canada, Ltd. (otherwise known as Cominco), situated at Trail, B. C., Canada, the following are some of the materials that have to be handled: Gases. Sulphur dioxide, sulphur trioxide, carbon dioxide, carbon monoxide, oxygen, hydrogen fluoride, ammonia, hydrogen sulphide, and oxides of nitrogen. Liquids. Solutions of ammonium sulphate, ammonium sulphite, ammonium nitrate, caustic soda and potash, sulphuric acid, nitric acid, hydrofluo-silicic acid, hydrofluoric acid, phosphoric acid, aqua ammonia, and formic acid. Solids. Gypsum (containing phosphoric acid), ammonium sulphate, ammonium nitrate, phosphate rock, caustic soda, potash, and phosphate fertilizers.

Jan 1, 1951

By E. A. G. Colls

IN all branches of the chemical industry, corrosion plays a very costly part unless it is suitably com-batted, and as a result it is probably correct that chemical and design engineers are more corrosion conscious in the field of chemical industry than in others. Most metals occur in nature in combination with other elements. The refined or reduced state to which man converts them for his use, by removing the combining elements, leaves them in an unstable condition. Therefore in most of the media to which the metals are exposed they are constantly combining with the constituents of their environment, or in other words they are continually being corroded. Similarly, nonmetallic materials are corroded by undergoing chemical change. The rate at which corrosion takes place varies widely from metal to metal and medium to medium. In practically all cases the corrosion of metals in solutions (electrolytes) is electrolytic in nature and the rate of corrosion is dependent on many factors such as temperature, pressure, internal stresses, galvanic action, metal-ion concentration, and so on. In the chemical industry substances must be handled which are particularly corrosive to materials of construction. At the chemical plants of The Consolidated Mining and Smelting Co. of Canada, Ltd. (otherwise known as Cominco), situated at Trail, B. C., Canada, the following are some of the materials that have to be handled: Gases. Sulphur dioxide, sulphur trioxide, carbon dioxide, carbon monoxide, oxygen, hydrogen fluoride, ammonia, hydrogen sulphide, and oxides of nitrogen. Liquids. Solutions of ammonium sulphate, ammonium sulphite, ammonium nitrate, caustic soda and potash, sulphuric acid, nitric acid, hydrofluo-silicic acid, hydrofluoric acid, phosphoric acid, aqua ammonia, and formic acid. Solids. Gypsum (containing phosphoric acid), ammonium sulphate, ammonium nitrate, phosphate rock, caustic soda, potash, and phosphate fertilizers.

Jan 1, 1951

[Trans. No. Place Date Vol. Page 1. Wilkes-Barre, Pa May, '71.. 1 3 2. Bethlehem, I's Aug., '71.. 110 3. Troy, N. Y Nov., '71.. 113 4. Philadelphia, PaFeb., '72.. 117 5. New York, N. YMay, '72120 6. Pittsburgh, Pa Oct., '72.. 125 7. Boston, MassFeb., '73.. 128 8. Philadelphia, Pa.*May, '73.. 23 9. Easton, PaOct., '73.. 27 10. New York, N. Y Feb., '74211] [ ]

Jan 1, 1925

By N. F. Fiore, M. F. McGuire

THIS communication describes a series of experiments in which dislocation etch pitting was used to ascertain the depth of damage in crystals which were mechanically polished or which were cut with either a commercial metallographic cut-off wheel,* a com- All specimens were cut from single crystals of American Smelting and Refining Co. 99.999+ pct pure copper which were grown from the melt by the Bridge-man technique. The test specimens were disks, with faces being (111) planes and the disk axis a (111) direction. The disks were annealed in a vacuum of 10-5 Torr for 24 hr at 950°C prior to cutting or polishing and were given a light electropolishing in an ortho-phosphoric acid bath before etch pitting. Both Youngs1 and Livingston's2 reagents were used for etch pitting and the reagents gave identical quantitative results; however Livingston's reagent produced less staining and so all photomicrographs shown are of {111) surfaces etched with this solution. The surface of the annealed crystals showed well-defined subboundaries and a density of dislocations of about 1 X 106 per sq cm excluding those present in subboundaries, Fig. 1. The depth of cold work produced during mechanical polishing was determined after an annealed specimen was mounted in a paraffin holding block to protect it from extraneous damage. The exposed (111) surface was ground on metallographic papers and then polished on billiard cloth through 0.05-p alumina abrasive. It was necessary to remove about 0.3 mm (-0.01 in.) to obtain a structure representative of the annealed sur- face, indicating that the crystal was damaged to this depth during mechanical polishing. The cold work caused by standard cutting methods was measured in another series of tests in which cuts

Jan 1, 1967

By E. T. Turkdogan

The activities of SiO2, FeO, and Fe2O3 are calculated from previous experimental data on the activity of oxygen in Fe-Si-O melts at 1550°C. Using the oxide-activity data, the free energy of formation of fayalite from its oxides is evaluated for 1550°C. A number of investigators1-4 contributed to the study of the state of oxidation of iron in SiO,-FeO-Fe,O3 melts and the phase equilibria in the system Fe-Si-O. In a more detailed study, Schuhmann and Ensio5 and Michal and Schuhmann% easured the state of equilibrium in the SiO,-FeO-Fe,O3 melts saturated with y-iron or silica or both under low-oxygen potentials and within the temperature range 1250" to 1350°C. Similar measurements were also made by Turkdogan and Bills7,' over wide ranges of composition and oxygen potentials at 1550"C. Using the experimental data on the oxygen activities in the ternary system, Schuhmann' calculated the activities of silica and ferrous oxide in Si0,-FeO-Fe2O3 melts for 1350°C. Adequate knowledge on the activities of the constituent oxides of melts is essential in the study of reaction-equilibria and reaction-kinetics in oxide-melts. With this in view, the activities of oxides in SiO2-FeO-Fe2O3 melts at 1550°C are computed using the experimental data of Turkdogan and Bills7'8 on the oxygen activities in these melts.

Jan 1, 1962

By Charles Catlett

My attention having been called several years ago to the possibility of increasing the yield of coke per ton of coal, as obtained in certain bee-hive ovens, I called the attention of the Institute to the matter at the New York meeting in 1899. I have had occasion since to witness the indifference with which this matter is ordinarily considered, and, on the other hand, the marked improvement which comes from even a most perfunctory effort in that direction; and I am almost tempted to say that nothing in connection with the coking of coal is at present so important. There are other factors, which are fundamental and necessary; but they have been considered already ; while the question of yield is, as a rule, absolutely ignored, or some figure is taken as the result of a special burning of one or two ovens, and the assumption is made that the whole battery is yielding at that rate. The uncertainty of this assumption I may illustrate by saying that, in my own observation, the burning of a single oven in a battery frequently gives, by actual weight, as much as 69 or 70 per cent. of merchantable coke, while the battery as a whole was yielding only an average of 63 per cent. Only from careful records, checked at least once a month, of the weight of the coal going to the ovens and the weight of coke produced, can any correct idea of the actual yield be gained, or methods be modified so as to produce good results; yet, as a rule, the crudest estimates are usually the only available data. In many cases there are reasons for this loose practice. The coal is mined by measurement; the payment for drawing the ovens is in proportion to the amount of cod which goes to them; and, not uncommonly, the royalty is so much a ton of coke, not of coal. The mine-manager is tempted to increase the volume of coal mined which is paid for as a ton, and to do the same thing in charging the ovens. Nor does he

Jan 1, 1903

By LESTER H. WOOLSEY

IT IS doubtful whether anything new can be said upon this subject and, therefore, it is with considerable hesitation that l prepare this paper. On account of my recent connection with the Department of State as its law- officer, perhaps I will be pardoned if I discuss this subject briefly from the point of view of that branch of the Government. , I cannot, of course, speak for that department, since I have-no connection with it at-present, but it may be helpful if I set down certain* of the factors which in my opinion and from my experience have a bearing on this international problem. With oil-burning ships, motor vessels, motor vehicles, airplanes-all consuming, astonishing quantities of petroleum or petroleum products; with the United States having within its borders only 12 per cent. of the petroleum resources of the world, and consuming about 70 per cent. of the world's output; with the more enterprising nations wide awake to the necessity ; of obtaining and preserving as large a share as possible of the oil resources extant ; the 'problem is peculiarly and in a, very practical sense an international one.

Jan 1, 1921

Jan 1, 1892

By H. A. Davies

DURING a current program of research on the structure and properties of liquid sodium alloys, the need arose for information on the solubilities as a function of temperature of several B subgroup metals in liquid sodium. In the absence of reliable information in the literature for several of these systems, par- ticularly at temperatures in the range 100° to 300°C, an apparatus was constructed to determine solubilities by a direct melt-sampling technique, followed by wet-chemical analysis for both sodium and the solute metal. The details of the technique have been described previously.' The solubility of indium in liquid sodium was determined at eight temperatures in the range 100° to 270°C. The solubility as a function of temperature is shown on Fig. 1; this represents the liquidus line over this composition range. A cooling curve was plotted after the completion of the sampling and an arrest was observed at 94.9°C which must be interpreted as being the result of a eutectic reaction. By extrapolation of the liquidus to this temperature, the eutectic composition was estimated to be about 0.25 at. pct In. The present estimate of the eutectic temperature and composition are in good agreement with the values of 96.0° to 96.2°C and between 0.28 and 0.45 at. pct In, respectively, which were reported by Heycock and Neville.2 However, no further information on the liquidus of this system at the sodium-rich end could be found in the literature for comparison. One compound: NaIn, has been reported in this sys-

Jan 1, 1968

By M. E. Straumanis, R. P. Shodhan

LATTICE parameters of molybdenum of various purities are summarized in Table I. The latter shows that the parameter fluctuates between 3.1467 and 3.1475A. The room-temperature expansion coefficient a is also not well-known as values from 4.90 to 5.20 x 10-6 can be found in the literature.=-' It, therefore, seemed appropriate to repeat the measurements under exactly controlled conditions, using high-purity Hilger molybdenum powder (containing 0.0015 wt pct of Fe, 0.005 of Si and traces of other elements) and a 99.95 pct pure Sylvania Electric preparation (containing Cr, Fe, Ni, Si, Sn, and C in amounts of 50 ppm of each and in still smaller amounts Cu, Pb, Mg, and Mn). Of course, both samples could have contained at least 0.01 pct of oxygen in form of a surface oxide. However, oxygen, because of its small solubility in molybdenum, does not influence its lattice constant.g The determinations were made in a cylindrical precision X-ray camera, 64 mm in diam, the temperature of which was controlled within *0.05"C, by inserting it into a special thermostat." To exclude the film shrinkage effect (after the development of the film), the asymmetric film placement method was used." Absorption corrections (e.g., by extrapolation)" were unnecessary because of the use of a thin Li-B-glass fiber (about 0.08 mm in diam) which was fastened to the sample holder of the camera and dusted with the fine molybdenum powder. Cum radiation of the wavelength 1.389350 kX was applied because it produced in 30 min the line (420) having a high Bragg angle of about 81.6 deg. The conversion factor of 1.00202 gave the results in angstroms. To obtain the expansion coefficient a, exposures were made at various temperatures t, see Fig. 1, on at least two films at each temperature. The films were measured with a componator and the lattice constants a were calculated. The expansion coefficient was found from: where a2s is the constant at 25°C and A is the change in a and t. The same equation (knowing a) was used to reduce all the constants obtained at various temperatures to that of 25"C, Table 11. The probable error S507p (at a 50 pct confidence limit) was calculated from the reduced constants:

Jan 1, 1969

By A. A. Blow

The productive area of the Leadville mining district immediately adjoining the city of Leadville, which, by its wonderful richness, has attracted the attention of the mining world for the past twelve years, may, with a few exceptions, he considered as divided into seven local mining centers, separated one from another by the topographical features of the country, and designated by common consent as Fryer Hill, Yankee Hill, Breece Hill, Rock Mill, Printer-Boy Hill, Iron Hill, and Carbonate Hill. Of these seven distinot mining localities, or groups of mines, the central one, Iron Hill, is the one of greatest importance and interest. It was the scene of the earliest discovery of carbonates, as far back as 1875, and since that time has always maintained its position

Jan 1, 1890

Photographs of Officers

Jan 1, 1923

By Edward Keller

In a paper, " A Study of the Elimination of Impurities from Copper-Mattes, etc.," presented to the Institute at the Atlantic City meeting, February, 1898, I gave certain figures which I called the relative slaggability in refining copper. In that paper* will be found the following pertaining to this subject: Relative Slaggability in Refining Converter-Copper. Cu. Pb. Bi. Sb. As. Se, Te. 1 129.5 1.13 7.30 5.22 0.81 and Relative Slaggability in Refining Electrolytic Copper. Cu. Pb. Sb. As. 1 41 9.97 7.13 Since there is a, possibility of misinterpretation of the above values, the following supplementary information may seem justified in explanation. As the contents of impurities in the unrefined or crude copper were unknown, the contents of the refined copper were substituted therefor, merely in order to obtain the two series of figures for comparison. These figures are higher than they would be had I been able to take the correct ones for the unrefined copper. The high figure, 129.5, for lead, in the case of converter-copper, means simply that more lead was slagged from the crude copper than remained in the refined copper; or, in definite values, that to 1 per cent. of copper slagged, the ratio of the lead gone into the slag and the lead remaining in the refined copper is 129.5 : 100. It is possible to approximate the true slaggability much more closely by adding the quantities of impurities in the refined copper to those in the slag, thus obtaining values for the crude copper in which the amounts volatilized are ignored (the latter

Jan 1, 1901

By G. Willard Quick, John R. Freeman

Jan 1, 1930

By F. Rosenblum, P. Spira, F. Kitzinger

The possibility of increasing the efficiency of mineral processing plants by means of computer control has prompted metallurgists to examine their flowsheets more critically in order to develop practical control strategies. Control schemes in use to date generally rely on the automation of traditional and previously manually regulated control loops, e.g., the addition of reagents to maintain a constant assay or a constant pH. This approach is predicated on the availability of well established primary sensors such as pH electrodes or on-stream analyzers. Noranda Research Center, in cooperation with Noranda Group concentrators, has developed a froth level monitor and a pulp density meter adaptable to this type of control. Although some of the basic principles on which they are based have been known for some time, their incorporation into the design of reliable, direct-reading instruments which can be interfaced with a computer is believed to be novel.

Jan 4, 1979