Search Documents

By W. A. Backofen

THE preferred orientations, or textures, resulting from many of the various methods for testing and forming metals have been the subject of numerous investigations.1,2* Despite this large amount of work, however, only a few limited studies have been made of the texture that is developed by torsional deformation. Ono3 found that in severely twisted wires of copper and aluminum a [Ill] direction lies parallel and a [1101 direction perpendicular to the longitudinal axis of the wire. Sachs and Schiebold4 have reported that a double-fiber texture exists in a twisted aluminum wire with both the [Ill] and [loo] directions parallel to the axis of the wire. Twisted iron wires have also been examined by Ono.8 Both the [1101 and [1121 directions were reported as parallel to the axis of the wire. Goss5 concluded from a study of twisted rods of a low-carbon steel that the preferred orientation existing at fracture is quite complex, but that many grains have a [1101 direction parallel to the axis of the wire. In addition to the earlier experimental work, some suggestions have been made about the possible nature of the torsion texture. These suggestions are based on the results of many experiments which indicate that the cold-working texture of a particular metal is largely determined by the geometrical change in shape that the metal undergoes during plastic deformation.1,6 Hibbard and Yen7 have considered the problem of deformation textures and have presented an analysis which is able to explain why equivalent changes in shape should yield similar textures. Therefore, a knowledge of the principal strains associated with torsional deformation would seem helpful in the interpretation of the torsion texture. The necessary analysis has been made of the state of strain in an element of metal lying in the surface of a cylindrical rod or tube that has been subjected to pure torsion.8,9 This analysis shows that the directions of the principal normal strains rotate continuously within a torsion specimen while it is being twisted. After the first infinitesimal amount of twisting, these directions make angles of 45" with the longitudinal axis of the bar. They rotate from this position as twisting proceeds, and after an infinite amount of twisting, the direction of the principal tensile strain is perpendicular, and the direction

Jan 1, 1951

By John H. Holloman

In recent papers, O'Neill,' Vivian, and Zener and Hollomon3 have reviewed some of the information concerning the relations between stress and strain during plastic deformation. Since further information has been obtained since these reviews were published, this paper attempts to further coordinate and amplify the knowledge concerning the plastic deformation of metals in simple tension. Ordinarily the results of tensile tests of metals are presented as graphs in which the load divided by the original area is plotted as a function of the percentage of elongation measured over some specified gauge length. The interpretation of graphs of this sort is limited, since the stress required to deform the metal at any stage of the deformation is actually the load divided by the instantaneous rather than the original area. Furthermore, each increment of the deformation is performed on metal that has been previously deformed, and, as pointed out by Ludwik,4 the strain could be more effectively defined: where e is the strain and AO and A are, respectively, the original and instantaneous areas. The results of the tensile tests can be more effectively presented and interpreted if the stress* (load divided by actual area) is .lotted as a function of the strain as defined above. A schematic curve of this type is presented as Fig. I. In a previous paper,6 the concept of Ludwik7 concerning the flow and fracture of metals was successfully employed to explain some of the puzzling results of notched-bar impact tests of steel. It appears that the use of this concept ii; very fruitful and should be kept in mind in any study of the deformation charactcristics of metals. Ludwik considered that a flow stress-strain curve of a metal was essentially a locus of points that described the stress required for plastic flow of an infinite numbcr of specimens, each with a different strain history determined by the preceding part of the flow curve Each of these specimens can also be considered to have a fracture strength. Uniortunately (or fortunately depending upon the point of view), all the specimens, except the one deformed to the fracture strain, flow and do not fracture. Even though the metals do not fracture, the concept of a fracture-strength curve seems

Jan 1, 1945

By John H. Hollomon

IN recent papers, O'Neill,1 Vivian,2 and Zener and Hollomon3 have reviewed some of the information concerning the relations between stress and strain during plastic deformation. Since further information has been obtained since these reviews were published, this paper attempts to further coordinate and amplify the knowledge concerning the plastic deformation of metals in simple tension. Ordinarily the results of tensile tests of metals are presented as graphs in which the load divided by the original area is plotted as a function of the percentage of elongation measured over some specified gauge length. The interpretation of graphs of this sort is limited, since the stress required to deform the metal at any stage of the deformation is actually the load divided by the instantaneous rather than the original area. Furthermore, each increment of the deformation is performed on metal that has been previously deformed, and, as pointed out by Ludwik,4 the strain could be more effectively defined: [e = In A t][I] where a is the strain and Ao and A are, respectively, the original and instantaneous areas. The results of the tensile tests can be more effectively presented and interpreted if the stress* (load divided by actual area) is plotted as a function of the strain as defined above. A schematic curve of this type is presented as Fig. I. In a previous paper,6 the concept of Ludwik7 concerning the flow and fracture of metals was successfully employed to explain some of the puzzling results of notched-bar impact tests of steel. It appears that the use of this concept is very fruitful and should be kept in mind in any study of the deformation characteristics of metals. Ludwik considered that a flow stress-strain curve of a metal was essentially a locus of points that described the stress required for plastic flow of an infinite number of specimens, each with a different strain history determined by the preceding part of the flow curve. Each of these specimens can also be considered to have a fracture strength. Unfortunately (or fortunately depending upon the point of view), all the specimens, except the one deformed to the fracture strain, flow and do not fracture. Even though the metals do not fracture, the concept of a fracture-strength curve seems

Jan 1, 1945

By A. M. Gaudin

The flotation process has been applied extensively in the mineral and chemical fields. This paper reveals results obtained by an exploration of an application to the biological field. In many ways this study was indeed an exploration since so many factors are different. In the mineral field, the particles, both those floated and those not floated, cover a wide range of sizes and shapes; in the biological field, the particles of one population are primarily of one or two sizes and one or two shapes. This identity in size and in shape gives biological systems the advantage of homogeneity. In the mineral field the particles may be as coarse as a millimeter; in the biological field the size may be a micron, or less. In the mineral field the particles may have a gravity several times that of water so that their apparent gravity is quite substantial. Microorganisms, on the other hand, may have a gravity so near that of the liquor that their settling velocity in the liquor is vanishingly small. These two facts conspire to make bubble-particle encounter in the pulp-body less likely. Finally, microorganisms are living, reproducing, and dying-all of which does not help the experimenter get a balance of materials. The analytical problems, too, are extraordinarily difficult, for the organisms can contain only elements that occur in their environment, although at a different level of concentration. The chemical composition of the surface of microorganisms is readily altered. In spite of these areas of difficulty, microorganisms can be floated to leave practically water-clear tailing, they can be floated from each other and, in fact, the same organism can be fractionated into a float that differs from the sink. SIZES AND SHAPES OF ORGANISMS Most ore pulps are described with reference to the percentage of the pulp that is fine enough to pass a 200-mesh sieve. Thus a copper-ore pulp may be 80% -200 mesh. Since 200 mesh equals 74 µ, a 2000-mesh particle would be 7.4 µ in diameter, and a 20,000-mesh particle would be 0.74 µ. The microorganisms with which this work is concerned are of the order of magnitude of 20,000 mesh. We have worked with Escherichia coli, the colon bacillus, Bacillus cereus, Bacillus subtilis, Bacillus megaterium, and Serratia marcescens. In some pioneer work, Dognonl,2 reported the use

Jan 1, 1962

By Irving Crosby

ELECTRICAL prospecting by potential methods has been applied to mining problems for some years and determinations of the depth to bed rock have been made, but so far as is known it has not been used previously in the solution of civil engineering problems, such as investigating the foundations of dams. During the past winter and spring the senior author has been engaged as consulting geologist in studying the site of a large darn on the upper Connecticut River and has had the satisfaction of introducing electrical prospecting to foundation problems. The valley across which the dam is to be built is underlaid by a deeply buried preglacial gorge which is filled with glacial deposits. An extensive drilling campaign was in progress, but the work was unusually slow and expensive on account of the number of boulders in the overburden. The necessity of speeding up the work was pressing and it was decided that much of the needed information could be obtained by geophysical methods. After investigating the various methods and conferring with the company engineers and with the consulting engineer, Albert Crane, a contract was made with the Schlumberger Electrical Prospecting Methods, and an observer with apparatus was sent to the dam site the first of April, 1928. The problem was to determine the depth to rock at various points in order to prepare a contour map of the bed-rock surface and outline the buried gorge in the vicinity of the dam site. Over one hundred determinations of depth have been made and the bed-rock topography, is now known in considerable detail. In addition, some information has been obtained about the nature of the overburden. The drilling has been continued; in fact, two additional drills have been put to work, and the electrical determinations have been checked at several points. At one of these the depth to rock given by the electrical work was 142 ft. and the drill found rock at 147 ft., an error of less than 4 per cent. The electrical work has also been checked by the geological study, and it has been found that when the electrical determinations are in agreement with the geological expectations they are probably reasonably accurate. When the electrical interpretation of the sub-surface topography is incon-

Jan 1, 1928

By O. N. Carlson, A. L. Eustice

The tensile properties of iodide vanadium were determined as a function of hydrogen concentration. It was shown that the presence of 10 ppm H is sufficient to cause embrittlement of vanadzum over a limited temperature range. The temperature of the observed ductility mininlum is approximately -l00°C, this being a function of strain rate and hydrogen concentration. The yield stress of hydrogenated vanadium is raised sharply in the brittle temperature range. THE present investigation was initiated to determine the effect of hydrogen on the tensile properties of high-purity vanadium as a function of temperature and the role of hydrogen in the brittle-ductile transition. Loomis and Carlson&apos; reported a change from ductile to brittle behavior in iodide vanadium at -110°C with a return of ductility at temperatures below -140°C. Vanadium wire containing 270 pprn of hydrogen was brittle at room temperature while wire containing 100 ppm was ductile under the same conditions. Roberts and Rogers&apos; reported a ductile-brittle-ductile fracture sequence in vanadium containing 400 to 600 ppm of hydrogen. Their data show that hydrogenated vanadium is ductile at 150"C, brittle at room temperature and ductile again at -196°C. Magnusson and Baldwin found a minimum in ductility in vanadium containing 80 ppm hydrogen from tensile tests performed at several strain rates. Information available on the vanadium-hydrogen equilibrium system4 is somewhat incomplete. The absorption of hydrogen is exothermic in accordance with the decline in solubility with rising temperature. The limit of solid solubility at temperatures below 400°C has not been determined due to the difficulties in obtaining equilibrium at these temperatures. Data on the hydrides of vanadium are rather limited. Roberts6 studied the structure of VD,., by neutron diffraction, and observed the ordering of the deuterium atoms below -65°C into a primitive cubic cell with a lattice constant about twice that of the disordered bcc vanadium solid solution. EXPERIMENTAL PROCEDURE Vanadium of 99.9 pct purity was prepared by the iodide refining process6 for use in this investigation. This vanadium contained the following analyzed impurities; <20 pprn calcium, 150 ppm carbon, 200 ppm chromium, 30 ppm copper, 10 ppm hydrogen, 200 ppm iron, <20 ppm magnesium, <20 ppm nickel, <5 ppm nitrogen, 150 ppm oxygen, <50 ppm silicon, and <20 ppm titanium. specimen Preparation—Tensile specimens were machined from swaged rods of iodide vanadium. The

Jan 1, 1962

By Ralph Hultgren, Louis A. Carapella

When F. Heuslerl found in 1898 that certain alloys containing only copper, manganese, and tin were ferromagnetic, the discovery excited a great deal of interest and led to numerous investigations. It was early found that tin could be replaced by aluminum, arsenic, antimony, bismuth, or boron without destroying the ferromagnetic nature of the alloys.2 Copper may also be replaced by silver.% All these alloys have come to be known as "Heusler alloys." The aluminum alloys apparently were the most magnetic and have been most extensively investigated. However, no agreement has yet been reached as to the source of the ferromagnetism arising from these nonferromagnetic elements. Absence of reliable quantitative data makes speculation hazardous. The value of much of the earlier work was vitiated by lack of necessary precautions against contamination, and by lack of close control of heat-treatment. It was only recently established that in aluminum Heusler alloys4 the ferromagnetism arose from a single phase, an ordered body-centered-cubic structure. With modern methods of preparation, heat-treatment, and X-ray examination, it is possible to prepare these alloys without contamination, to heat-treat them intellgently, and to determine what phase or phases are present in the finished sample. In the present investigation, a series of pure alloys in the comparatively neglected copper-manganese-tin system have been prepared, which consist of a single, body-centered-cubic structure (the beta phase) and whose compositions vary within wide limits. The magnetic saturation values of these single-phase alloys have been quantitatively determined, so that considerable data on the effect of composition on the ferromagnetism have been made available. In the course of the investigation some information on the extent of the stability of the beta phase and the nature of phases in adjacent regions of the ternary diagram has been accumulated. Anomalies in earlier data. have been explained, and alloys have been prepared that are much more strongly magnetic than any previous Heusler alloys. Previous Work In the original work of F. Heuslerl and coworkers,2 a maximum magnetic saturation value of I = 107 was found at the composition Cu6Mn3Sn, while a value for CusMnAl of I = 443 was early measured. Ross and Gray5 found a second maximum at the composition Cu2MnSn, which was much more magnetic than Heusler&apos;s original alloy. F. Heusler6 hen reinvesti-gated the system, confirmed their results,

Jan 1, 1942

By Louis A. Carapella, Ralph Hultgren

When F. Heuslerl found in 1898 that certain alloys containing only copper, manganese, and tin were ferromagnetic, the discovery excited a great deal of interest and led to numerous investigations. It was early found that tin could be replaced by aluminum, arsenic, antimony, bismuth, or boron without destroying the ferromagnetic nature of the alloys.2 Copper may also be replaced by silver.% All these alloys have come to be known as "Heusler alloys." The aluminum alloys apparently were the most magnetic and have been most extensively investigated. However, no agreement has yet been reached as to the source of the ferromagnetism arising from these nonferromagnetic elements. Absence of reliable quantitative data makes speculation hazardous. The value of much of the earlier work was vitiated by lack of necessary precautions against contamination, and by lack of close control of heat-treatment. It was only recently established that in aluminum Heusler alloys4 the ferromagnetism arose from a single phase, an ordered body-centered-cubic structure. With modern methods of preparation, heat-treatment, and X-ray examination, it is possible to prepare these alloys without contamination, to heat-treat them intellgently, and to determine what phase or phases are present in the finished sample. In the present investigation, a series of pure alloys in the comparatively neglected copper-manganese-tin system have been prepared, which consist of a single, body-centered-cubic structure (the beta phase) and whose compositions vary within wide limits. The magnetic saturation values of these single-phase alloys have been quantitatively determined, so that considerable data on the effect of composition on the ferromagnetism have been made available. In the course of the investigation some information on the extent of the stability of the beta phase and the nature of phases in adjacent regions of the ternary diagram has been accumulated. Anomalies in earlier data. have been explained, and alloys have been prepared that are much more strongly magnetic than any previous Heusler alloys. Previous Work In the original work of F. Heuslerl and coworkers,2 a maximum magnetic saturation value of I = 107 was found at the composition Cu6Mn3Sn, while a value for CusMnAl of I = 443 was early measured. Ross and Gray5 found a second maximum at the composition Cu2MnSn, which was much more magnetic than Heusler&apos;s original alloy. F. Heusler6 hen reinvesti-gated the system, confirmed their results,

Jan 1, 1942

By R. R. Wilson, Robert Henderson

The Cassidy Colliery operated by the Granby Consolidated Mining Smelting & Power Co., Ltd., is situated about 9 miles in a southerly direc tion from the city of Nanaimo on Vancouver Island. The coal seam worked, which is called the Douglas bed, outcrops in the western part of the property, dipping easterly, and is opened by a slope 7 by 14 ft. in the clear, and is timbered by 12 to 14-in. framed sets of timber, 4 ft. center to center. A separate manway provides for a traveling road and at the same time forms an intake airway. The general average of the dip of the seam at Cassidy is 18º, and varies in thickness from 1 to 25 ft., averaging about 8 ft. The main slopes follow straight down the dip a distance of 4845 ft. At the bottom of the main slope two rock tunnels were driven a distance of 1500 ft. to the south, cutting through a fault, and opening up an area in the same seam which is known as No. 7 South Section. The coal is found in this section at a vertical depth of 1560 ft., and is very soft and friable. The immediate roof is a strong, sandy. shale overlain by massive sandstone while the floor is a light-colored shale, hard when freshly exposed. It does not soften materially on exposure. In the folding of the coal measures a great thrust caused a movement along the coal seam as indicated by the slickensided nature of the coal. The floor has buckled and this has rolled and squeezed the coal so that with rare exceptions it shows no normal bedding but curved slip planes, which frequently start at right angles to the floor, curving upward and then in the direction of the dip. As such planes are slickensided it is probable that there is a coating of clay which is more or less impervious to gas. Outbursts of Gas and Coal Outbursts of gas and coal have occurred in this mine previous to 1921, but not until June 14 of that year was a complete record kept of them. No outbursts occurred above the fourth levels, or, in other words, until a vertical depth of about 900 ft. was reached. Since that time quite a

Jan 1, 1927

By Carl Zapffe

The object of the Bradley process is to free manganese oxide from its associated gangue and separate the contained iron oxide by dissolving the manganese and precipitating it from the solution. This results in producing two oxides as concentrates, the one to be converted into a manganese sinter and the other into an iron sinter. The manganese sinter may be made to contain as high as 70 per cent. inanganese and as low as 1 per cent. silica, with phos&apos;phorus not to exceed 0.02 per cent, and from that figure downward to about 0.005 per cent., and with sulfur at 0.007 per cent. The iron sinter contains about 2.50 per cent. manganese, making the total recovery of the manganese 98 per cent. The method involves selective roasting, which converts the manganese into a form in which it is soluble in an aqueous solution of ammonium sulfate, then precipitating the manganese as a hydrate by using ammonia gas, then stabilizing and washing the hydrate, followed by sintering; concurrently most of the iron oxide is converted by roasting into an insoluble form and becomes a residue with magnetic qualities, which makes possible the recovery of much of the iron in the ore. Leaching manganese by using sulfur dioxide gas was shown possiblc Inany years ago. Mr. Bradley tried it for a year, working in conjunction with the original experimenters of that method, and found that while relatively pure inanganese oxide could be produced, the likelihood of developing a commercial process along this line was not very encouraging. He also attempted leaching with nitric and sulfur acids, but the cost of recovery mounted and the quality of the product was not as good Mr. Bradley tried nearly every leaching method proposed, and the expen-ments were made on a large scale in the spacious laboratories of John C. Wiarda & Co., in Brooklyn, N. Y. Insufficient encouragement was discernible in the results obtained. Upon the suggestion of N. Arthur Laury, of John C. Wiarda & Co., Bradley undertook using arnrnoniurn sulfate. Because a high rate of recovery appeared feasible, Bradley planned the erection of a 4-ton pilot plant at the State of Minnesota Mines Experiment Station, at Minneapolis. The results of that work are described in this treatise.

Jan 1, 1929

I. PRESIDING OFFICER. At all business meetings of the Institute the President, or, in his absence, the First Vice-President, or, in the absence of both of them, any other Vice-President or Director, chosen by the meeting, shall preside. At all other meetings of the Institute the President, or, in his absence, one of the Vice-Presidents, shall preside. If none of these be present the meeting shall elect a Chairman. II. ORDER OF BUSINESS. At each business meeting of the Institute the order of business shall be as - follows : 1. Reading of minutes-of preceding meeting. 2. Report of the President. 3. Report of the Treasurer. 4. Report of the. Secretary. 5. Election of Directors. 6. Reports of Standing Committees. 7. Reports of Special Committees. 8. Special Orders. 9. Miscellaneous business. This order of business may be changed at any meeting, by a vote of a majority of the Members and Associates present. At all sessions of the Institute, other than business meetings, the order of pro¬ceedings and the time of adjournment shall rest in the discretion of the presiding officer. III. SECRETARY OF THE INSTITUTE. The Secretary shall keep a record of the proceedings of all meetings of the Institute. He shall be custodian of the corporate seal, of the minute books, and of all legal documents belonging to the Institute. He shall have charge, on behalf of the Institute, of all correspondence except such as pertains directly to the office of the Treasurer. He shall notify all Officers and Directors and all members of committees of their election and appointment; shall issue notices of all meetings of the Board, and of the annual and other business meetings of the Institute; and shall; in calling, special meetings of the Directors, specify the objects of such meetings. He shall act as clerk at all the meetings of the Board of Directors and at all meetings of the Institute. The Secretary shall be custodian of all technical or scientific papers submitted to the Institute for its consideration, shall have general charge and supervision of the editing and proof-reading of all material published by the Institute, and of the distribution thereof, and be ex officer Chairman of the Committee on Publications. On the first day of May following the year in which each volume of Transac-

Jan 1, 1925

WILLIAM H. KOBBÉ (communication to the Secretary*).-I have read with much interest the discussion of my paper by Arthur Knapp and I. N. Knapp published in the March Bulletin. These discussions apparently assume that my paper advances a. number of ideas that are not intended: 1. That the total sandbody or pay is to be removed. 2. That upon bringing this sand and oil to the surface 100 per cent., or perfect separation, can take place. 3. That this tremendous quantity of sand is then hauled away in wagons and distributed as road material. The paper raider discussion is not a theoretical treatment of the subject but is the result of actual experience in oil production under the conditions mentioned.. That wells that produce sand produce in ore oil, and the best operating methods to bring this about are fully treated. It is, of course, impossible to remove all the oil sand underlying a property, but the greater the amount removed the greater becomes the production of oil. As stated in my paper, the surface disposal of this large volume of sand is a problem and the only use to which it can be put is road surfacing; but I did not intend to convey the idea that all this sand was thus used. Only a very small quantity was required on the company&apos;s roads, and two wagons only were employed for this purpose. The remaining sand accumulated in the numerous "washes" and sumps. Although this sand contained sufficient oil to stain the hands, it was, surprisingly dry and could be easily shoveled. As stated in the paper, "the piles of sand are gradually freed of their oil content and a crust forms on their surface which will bear the weight of a man." I consider this a high degree of separation. A small amount of oil necessarily remains in the sand and is held there by capillarity. Otherwise it would be useless as a road binder, and, furthermore, to recover such oil special processes of treating are required. Arthur Knapp says, "of the total volume produced by pumping, not more than 4 or 5 per cent. can possibly be sand." I cannot agree with this statement as I have managed many properties where the wells were so operated that the amount of sand produced was five times this figure.

Jan 6, 1917

By E. G. Leonardon, Irving B. Crosby

ElectRical prospecting by potential methods has been applied to mining problems for some years and determinations of the depth to bed rock have been made, but so far as is known it has not been used previously in the solution of civil engineering problems, such as investigating the foundations of dams. During the past winter and spring the senior author has been engaged as consulting geologist in studying the site of a large dam on the upper Connecticut River and has had the satisfaction of introducing electrical prospecting to foundation problems. The valley across which the dam is to be built is underlaid by a deeply buried preglacial gorge which is filled with glacial deposits. An extensive drilling campaign was in progress, but the work was unusually slow and expensive on account of the number of boulders in the overburden. The necessity of speeding up the work was pressing and it was decided that much of the needed information could be obtained by geophysical methods. After investigating the various methods and conferring with the company engineers and with the consulting engineer, Albert Crane, a contract was made with the Schlumberger Electrical Prospecting Methods, and an observer with apparatus was sent to the dam site the first of April, 1928. The problem was to determine the depth to rock at various points in order to prepare a contour map of the bed-rock surface and outline the buried gorge in the vicinity of the dam site. Over one hundred determinations of depth have been made and the bed-rock topography is now known in considerable detail. In addition, some information has been obtained about the nature of the overburden. The drilling has been continued; in fact, two additional drills have been put to work, and the electrical determinations have been checked at several points. At one of these the depth to rock given by the electrical work was 142 ft. and the drill found rock at 147 ft., an error of less than 4 per cent. The electrical work has also been checked by the geological study, and it has been found that when the electrical determinations are in agreement with the geological expectations they are probably reasonably accurate. When the electrical interpretation of the subsurface topography is incon-

Jan 1, 1929

By AIME

Rapid exhaustion of iron ore in Minnesota&apos;s Mesabi range has led the Jones & Laughlin Steel Corp. to develop the world&apos;s largest open quarry mine for magnetite iron ore, at Star Lake, N. Y. Already contributing more than one eighth of the total iron ore used by the Corporation, the expanding Benson mines are destined to become Jones & Laughlin&apos;s important source of ore within the next ten years. In 1947 over 650,000 long tons of high-grade ore was produced. Output this year is expected to reach 800,000 long tons and studies are under way to increase production further. The future of the Benson mines is assured as present indications show large reserves of ore. The property, briefly described in M & M for November 1943, then under

Jan 1, 1948

By A. Sutulov

The segregation process, an alternative to benefi-ciation of oxidized and mixed sulfide-oxide copper ores, is studied here with particular emphasis placed on time, temperature, and coke and salt percentage factors. The results show that in a segregated charge, the copper assay of the coarsest fractions normally is of the same order as the copper assay of the tails obtained from grinding and flotation of the same charge. This observation suggests the possibility of limiting or even eliminating the grinding step from the flowsheet of a segregation plant. The segregation process, which offers an alternative to beneficiation of oxidized and mixed sulfide-oxide copper ores, was discovered in 1923 by Moulden and Taplin1,2 who were attempting to apply the Perkins process3&apos;4 to a Chilean ore from the Sagasca mine. After a number of investigations and pilot plant tests,&apos;-&apos; the segregation process became a successful industrial operation.&apos;r9 The process aroused considerable interest in Chile because of the existance of large reserves of oxidized copper minerals which could not be treated by conventional hydrometallurgical methods because of the high consumption and prohibitive cost of sulfuric acid. During the last two years, the Mineral Dressing Dept. of the Institute de Investigaciones Tecnology cas of University of concepci6n (Chile) has carried out a test program on 23 different ore samples representative of the national territory. These tests were carried out on a semi-continuous and batch scale with a rotary, automatically controlled and gas-fired furnace (supplied by Bartlett and Snow, Fig. 1). The results of these tests indicate that out of the 23 samples 20 can be successfully treated by this process with recoveries of copper ranging from 85 to 95%.10,11 The purpose of this paper is to treat some specific problems related to the segregation process. TIME AND TEMPERATURE FACTORS Time and temperature of calcination play an important role in the segregation process. When moderate salt and coke conditions were maintained (each of reagents was added in the quantity of 1 — % wt), systematic testing easily demonstrated the influence of these two factors on segregation and flotation recovery. The pertinent results are summarized in Fig. 2. To determine what specific changes the segregation process made on the ore, the samples, segregated at 700°C for different periods of time and under standard conditions, were granulometrically analysed and

Jan 1, 1963

By Thomas M. Drown

Remarkable as have been the direct results of Danks&apos;s puddler, there are some indirect and incidental results, which are well worthy of study for their intrinsic value and suggestiveness. The success of Danks&apos;s machine is due mainly to the nature of the lining and the manner in which it is attached to the walls of the revolving chamber. Herein lies Danks&apos;s merit and good fortune. Given such a lining, and the success of the machine, as far as puddling iron is concerned, could easily be predicted. Other important results have, however, been obtained with this machine, which, though clearly explicable, were, nevertheless, unanticipated. These are the increased yield of bar-iron over the pig-iron charged, and the elimination of phosphorus, which, though not absolutely complete, is yet more decided than in the case of hand-puddling. As regards the increased yield, this is merely what we have a right to expect if we consider the puddling process to consist in the oxida tion of the carbon and silicon of the pig by the oxygen of the oxide of iron. That this result is attained, nearly to the extent that the theory requires, in Danks&apos;s puddler, and has never been more than partially attained by the most careful experiments in band-puddling, points clearly to the fact that the contact of the molten pig-iron with the oxide of iron is much more intimate and complete in the one instance than in the other. The action of puddling in Danks&apos;s machine may be considered to be twofold: first, the removal of the carbon, silicon, and phospho rus of the pig, which is the primary object, and, second, the produc tion of wrought iron direct from the ore, which is entirely an inci dental result. Intelligent metallurgists were not long in recognizing in this latter result a fact of deeper import and greater value than the attainment of a perfect puddling process. A new method

By Thomas M. Dr. Drown

REMARKABLE as have been the direct results of Danks&apos;s puddler, there are some indirect and incidental results, which are well worthy of study for their intrinsic value and suggestiveness. The success of Danks&apos;s machine is due mainly to the nature of the lining and the manner in which it is attached to the walls of the revolving chamber. Herein lies Danks&apos;s merit and good fortune. Given such a lining, and the success of the machine, as far as puddling iron is concerned, could easily be predicted. Other important results have, however, been obtained with this machine, which, though clearly explicable, were, nevertheless, unanticipated. These are the increased yield of bar-iron over the pig-iron charged, and the elimination of phosphorus, which, though not absolutely complete, is yet more decided than in the case of hand-puddling. As regards the increased yield, this is merely what we have a right to expect if we consider the puddling process to consist in the oxidation of the carbon and silicon of the pig by the oxygen of the oxide of iron. That this result is attained, nearly to the extent that the theory requires, in Danks&apos;s puddler, and has never been more than partially attained by the most careful experiments in hand-puddling, points clearly to the fact that the contact of the molten pig-iron with the oxide of iron is much more intimate and complete in the one instance than in the other. The action of puddling in Danks&apos;s machine may be considered to be twofold first, the removal of the carbon, silicon, and phosphorus of the pig, which is the primary object, and, second, the production of wrought iron direct from the ore, which is entirely an incidental result. Intelligent metallurgists were not long in recognizing in this latter result a fact of deeper import and greater value than the attainment of a perfect puddling process. A new method

Jan 1, 1874

ASIDE from the John Fritz Medal, in which the Institute participates through its representation on the John Fritz Medal Board, the, Institute itself has five major awards to make annually for excellence in technical papers, as follows The Robert W. Hunt Medal and Prize, The J E Johnson, Jr Award, The Lewisohn Platinum Prize to senior members, and the James Douglas Medal ROBERT W HUNT MEDAL AND PRIZE The partners of Robert W. Hunt established a fund which was presented to the Institute at a fitting ceremony on May 27, 1920, to establish an annual medal and a sum of money to be awarded under the following rules 1 The award shall consist of two prizes, first of a gold medal, second of a sum of money, a certificate to accompany each prize The money prize shall not be awarded to a member over 40 years of age, but under unusual circumstances, both prizes may be allotted to one person provided that he is not over 40 years of age In general it will be understood that the Committee shall award the money prize to the younger men, rather than the medal 2 The awards shall be made not oftener than once a year to that person or persons contributing to the Institute the best original paper or papers on iron and steel The scope of the term "iron and steel" shall be determined by the sub-committee consider¬ing the awards In general, papers dealing with the practical side of the subject have preference over those dealing with the theoretical side in recognition of the fact that Captain Hunt&apos;s main contributions to the industry have been in the improve¬ment of production and quality of material. 3 A sub-committee of three to five, including the Chairman of the Iron and Steel Committee, shall be appointed by the Iron and Steel Committee annually to adjudge the award subject to approval 4 The awarding committee shall submit its report to the Iron and Steel Committee at its October Meeting, and the award be certified to the Secretary of the Institute in time to permit the presentation to be made at the Annual Meeting of the Institute 5 The recipient of the award shall be designated "The Hunt Medallist " This prize is administered by the Iron and Steel Committee

Jan 1, 1923

Page Foreword. By Edmund M. Wise..................... 3 A.I.M.E. Officers and Dircctors...................... 4 Institute of Metals Division Officers and Committees............ 7 Institute of Metals Division Annual Award Certificate............ 8 Institute of Metals Division Lectures and Lecturers............. 9 Photograph of E. H. Dix, Jr., Institute of Metals Division Lecturer...... 10 PAPERS Acceleration of the Rate of Corrosion by High Constant Stresses. By E. H. Dm, JR. (Institute of Metals Division Lecture, T. P. 1204).......... 11 Variation of Internal Friction with Grain Size. By Clarence Zener and R. H. Randall. (T.P. 1146, with discussion) .............41 Changes in Damping Capacity during Annealing of Alpha Brass. By John T. NoRton. (T.P. 1168, with discussion)................49 An Electron Diffraction Study of Anodic Films. By R. A. HarrinQton and H. R. Nelson. (T.P. 1158).....................62 Determination of Orientations by Etch Pits. By Charles S. Barrett .and L. H. Levenson. (T.P. 1171, with discussion).............76 Process of Precipitation from Solid Solution, I—A Crystallographic Mechanism for the Aluminum-copper Alloys. By Carl H. Samans. (T.P. 1186). . . 85 Age-hardening of Aluminum Alloys, IV — Discussion of the Theory. By WilTJam L. Fink and Dana W. Smith. (T.P. 1083, with discussion). . . 95 Structure of Aluminum after Compression. By Charles S. BaRREtt and L. H. evensonON. (T.P. 1104, with discussion)................112 Recrystallization Texture of Aluminum after Compression. By ChaRlEs S. BarRett. (T.P. 1141, with discussion)................128 Plastic Deformation and Recrystallization of Aluminum Single Crystals. By J. A. Collins and C. H. Mathewson. (T.P. 1145, with discussion) . . . 150 Recovery and Recrystailization in Long-time Annealing of 70-30 Brass. By S. E. Maddigan and A. I. Blank. . (T.P, 1166, with disonssion).....170 Correlation of Deformation and Recrystallization Textures of Rolled 70-30 Brass. By R. M. Brick. (T.P. 1144, with discussion).........193 Tensile Deformation of Critically Oriented Brass Crystals. By H. L. Burghoff. (T.P. 1149).............................214 Recrystallization of Lead. By Paul A. Beck. (T.P. 1101, with discussion). . 222 Simple Method of Thermal Analysis Permitting Quantitative Measurements of Specific and Latent Heats. By Cyril Stanley Smith. (T.P. 1100, with discussion).............................236 Metallographic Study of Internal Oxidation in the Alpha Solid Solutions of Copper. By Frederick N. Rhines. (T.P. 1162, with discussion). . . . 246

Jan 1, 1940

By S. F. Reiter, R. W. Guard, J. H. Keeler

DURING the last several years the authors have been conducting tests on a tensile machine that autographically records load-elongation data. In certain tests at elevated temperatures on face-centered cubic, hexagonal close-packed, and body-centered cubic materials (binary alloys of nickel, zirconium, and iron), the load-elongation curve as shown in Fig. 1 reaches a maximum load (Pmax,) at relatively small amounts of strain and a large amount of elongation occurs subsequently with a continuously decreasing load, until finally localized necking and fracture take place. This early maximum load behavior has been found without the accompanying evidence of localized necking as has been assumed by some, or of evidence of cracking as observed by others.&apos; This behavior has also been observed by Nadai and Manjoinez whose results are in good agreement with ours. The prior strain, strain rate, test temperature, and crystal structure affect the observations. The influence of prior strain was observed in tests on unalloyed zirconium at 300°C in which specimens containing large amounts of prior strain (cold work) exhibited the type of curve shown in Fig. 1. No localized necking was observed after strain as much as that of point B. Annealed and recrystallized specimens of the same material showed a load-elongation curve with maximum load occurring after considerable strain hardening and at the beginning of localized necking. Interrupted tests (Fig. 2) show no loss in strength because of recovery or recrys-tallization during an interval at temperature without load. Recovery under stress such as found by Wood and Suiter3 in aluminum is now being investigated as one possible explanation. The strain rate is a contributing variable as shown in Fig. 3, a test on high purity nickel. Here the strain rate was decreased by a factor of ten during a test in which the maximum load was reached at a small strain. The slope of the true stress-true strain curve was positive with the more rapid strain rate and negative with the slower strain rate. In many binary ferrites an added effect of temperature has been observed. Fig. 4 shows the load-elongation plots for a binary ferritic alloy containing 2 pct Mo. The slope of the small portion of the stress-strain curve obtained at a strain rate of 0.01 mhr1 changes sign from negative to positive on going

Jan 1, 1955