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By W. M. Corse

W. M. CORSE,?Mansfield, Ohio.-The conservation of tin, in view of the shipping situation; is one of great importance. Several methods of conservation can be employed: 1. Reduction of the amount of tin in an alloy or compound. 2. Substitution of an entirely different metal or compound for tin. 3. A combination of the first and second methods. The second method is the one that I wish to discuss. Metallic aluminum has been known for a long time, and its use in copper alloys was discovered about 1855 by Lord Percy. The high cost of production of metallic aluminum retarded its commercial development, and it was not until the discovery of the electrochemical processes for its production that it came to be known as a common metal. I have been particularly interested, for the past few years, in working with the alloy known as aluminum bronze, which is usually composed of approximately 90 parts of copper and 10 parts of aluminum, by weight.

Jan 12, 1918

By C. S. Matthews, P. Hazebroek, H. Rainbow

It ha been suggested that lormation fractures created by well stimulation treatments will adversely affect sweep-out efficrency in injection operations. Fluid-flow model studies involving vertical fractures of various lengths and fluid systems of various mobility ratios have been carried out to study this subject. In addition, limited data have been obtained on one model containing a horizontal fracture. It was found that relatively long and highly conductive fractures (not generally obtained fracturing operations) were required to affect the sweep-out efficiency substantially. In a given case in the field an approximate distinction can be made between the presence of long conductive fractures and shorter or less conductive ones. This is done with pressure build-up analyses along with data on the relationship of fracture length and conductivity to well productivity. This type analysis shows that usually the fractures induced are either short or of limited conductivity and therefore do not damage sweep-out efficiency. INTRODUCTION Improved well productivity and in-jectivity can frequently be exploited in injection operations. Higher total throughput can yield improved economics. On occasion, the achievement of an increased productivity or injectivity in specific wells can bring about a more uniform sweep of the reservoir. Higher rates can be exploited particularly in water floods of "depleted" reservoirs where a rapid "fill-up" is desired and where low pressures contribute to low well productivity. The creation of fractures local to the wellbore is an excellent means for achieving these objectives. Even though fracturing has been employed in some floods with success,1"3 there still seems to be some reluctance to employ this tool for fear of undue damage to the flood pattern and ultimate recovery. We therefore need to examine the influence which fractures of varying length may have on flood performance and then determine the length of fractures which obtain in the field with conventional fracture treatments. A substantial influence of fractures on the recovery obtained at breakthrough of the injected fluid has been presented by Crawford and Collins for equal fluid mobilities for the line-drive pattern.4,5 In addition, the influence which a fracture has on the production performance after breakthrough and on the ultimate recovery warrants consideration in reaching a conclusion concerning the use of induced fractures in flooding operations. This report presents this type of data for the five-spot injection pattern for several fluid mobilities. In arriving at some conclusion concerning the fracture lengths obtained in field operations we must examine the performance characteristic most affected by the fracture. This is the change in the flow system as reflected in the change in productivity and pressure build-up behavior. A study of these changes is also presented in this report. RESERVOIR ANALOGS The X-ray shadowgraph technique, employing miscible displacement in porous models, has been used in the study of the influence of fractures on pattern sweep-out efficiency. The X-ray shadowgraph procedure is described in detail in an earlier report8. Fractures were represented by leaving the proper portion of the model surface exposed to either injection or production. This assumes the fracture resistance to be negligible compared to that of the formation. Actually the flow resistance in propped fractures obtained in the field is sometimes not negligible so that the results with this model indicate the maximum influence of the fracture. Two types of models were necessary to represent vertical fractures in a five-spot flood. These pattern elements are illustrated in Fig. 1. In studying the influence of the horizontal fracture, only one well spacing length to thickness ratio of 50 was used. The pool unit of a Carter Electric Analyzer was used in studying the influence of fractures on productivity and build-up behavior. The square drainage system of a well was represented by a network of 576 elements of equal volume and resistance. One-fourth of this drainage area was studied as a model unit using a network of 144 condensers and resistors. Vertical fractures were represented by a shunt directed from the well perpendicular to the drainage boundary. Horizontal fractures were represented by a circular shunt. Resistance of a shunt was varied in representing different conductivities for the fractures. FRACTURE DIRECTION AND LENGTH The direction at which a vertical fracture extends into the formation and its length and conductivity influence the sweep behavior. The two

By Thomas G. Murdock

EthIopia, the first country to be liberated from Axis domination, has recovered remarkably from the ravages of occupation and war. Mineral production has contributed significantly towards this recovery, as it has provided a means of obtaining foreign exchange and has given employment to hundreds of workmen whose maintenance otherwise would have presented a problem. Although primarily an agricultural country, never with a large mineral production, Ethiopia has within its borders a variety of minerals, both precious metals and nonmetallics. Some of these are important to the country as a national asset and others contribute greatly to local economy and can be expected to do so even to a greater extent in the future1 (Fig I). Physiography and Geology The Empire of Ethiopia is essentially a mountainous and volcanic country, in northeast Africa, situated principally between latitude 4° and 15°N and longitude 34° and 44°E. It is bounded on the north by Eritrea, on the northeast by French Somaliland, on the southeast by Italian Somaliland, on the south by Kenya Colony, and on the west by Anglo-Egyptian Sudan. These European possessions thus completely surround the country. Its access to the Red Sea is through Eritrea; to the Gulf of Aden, through French or British Somali- land ; and, to the Indian Ocean, via Italian Somaliland. These routes range in length from 40 to 250 miles. Ethiopia has an area of approximately 350,000 square miles, with a width from north to south of 625 miles, and a maximum length from east to west, along latitude 8°N, of about 875 miles. Physiographically the country is characterized by two very extensive sub-tabular plateaus: the Ethiopian Plateau to the northwest and the Somaliland Plateau to the southeast, separated by a long tectonic graben—the Rift Valley of the Galla Lakes and Danakil. The Ethiopian Plateau, deeply cut and notched by the drainage, slopes in a general northwest direction toward the Sudanese Plains and the valley of the Nile; the Somaliland Plateau slopes to the southeast, toward the Indian Ocean. The valley of the Galla Lakes and its extension to the northeast—the Awash River Valley, separates the plateaus, from Lake Rudolph to Danakil. This depression which constitutes a continuation or ramification of the Great Rift Valley of Central Africa joins in turn the trough of the Gulf of Aden and the Danakil-Eritrean Rift, continuations of the Red Sea and the Jordan Valley. The general basement of Ethiopia is made up of very old rocks, usually considered as Archaen.2 These rocks are represented by the metamorphic crystallines, such as gneisses, different kinds of schists, included lenses of crystalline limestone, and massive intrusives such as granites, diorites, and syenites, all cut by

Jan 1, 1949

By Michael Tenenbaum, C. C. Brown

Numerous investigatiolls have been carried out to determine the total oxygen present in the basic open-hearth bath and the results of these studies have clearly defined the factors controlling the bath oxidation during the period prior to deoxidation. On the other hand, very little is known concerning any changes in total oxygen content that may occur during deoxidation, tapping and teeming. The need for such additional data is continually becoming more apparent, since there is no strict technical basis for selecting any particular deoxidation practice. Many steels are made for the same purposes and to the same chemical analyses by widely differing practices. Apparently, each practice is satisfactory. However, it would be desirable to establish more definitely the effects and relative merits of the individual practices. Such information could be used to give a definite foundation for evaluating various types of deoxidation. In order to approach this problem, a study was made of the changes effected in the total oxygen content of several grades of steel by representative open-hearth deoxidation practices. To carry out such studies, it was necessary that a reliable testing procedure for determining the oxygen content of the steel bath and the ingot mold be established. Before entering on any extensive testing program, consideration was given to the available methods of obtaining steel samples and analyzing for oxygen. Testing Procedures It has been shown5-9 that in solidified steel oxygen may ekist in combination with iron, manganese, silicon, aluminum, titanium, chromium and carbon, depending upon the amount of these elements in the sample. In molten steel, however, there has been no direct distinction of the various oxides. Accordingly, the total active oxygen in the molten steel bath is designated by the symbol 0. During deoxidation, various oxides may be present either in solution in the molten steel or as solid or liquid inclusions. Any sample taken from the molten steel for oxygen analysis will include both the dissolved and the mechanically included oxygen. Similarly, samples of the solid steel product will also include the two forms of Oxygen' Methods of Samplirzg the Molten Steel Bath In order to obtain a true oxygen analysis from liquid steel, this element must be completely retained in the solidified sample. Several methods have been proposed whereby this stabilization can be effected. As early as 1915, Kichlinelo proposed a method for testing molten steel, in which the oxygen combined with some added aluminum. The concentration of the resultant aluminum oxide was determined by chemical analysis. This method was

Jan 1, 1945

By AIME AIME

THE STANDARD herewith submitted is the result of several years of research and consideration by the A.I.M.E. Technical Committee on Milling Methods. In the early work of this committee it was found necessary to undertake the development of a standard laboratory method for screen testing of ores. During the research stages the desirability of having this standard, when completed, approved as American Standard was brought out. In accordance with this idea, its initiation as a project of the American Standards Association (then the American Engineering Standards Committee) was approved by the latter body and the A.I.M.E. designated as sponsor. In 1929, the A.S.A., on recommendations of its advisory committee, the Mining Standardization Correlating Committee), authorized the A.I.M.E. to be sole sponsor for this project. The personnel of the Institute's Committee on Milling Methods was then increased to make it thoroughly representative of all diversified interests in the mining field. Two years ago the standard was circulated and has been given wide distribution. Early in 1932 the committee voted unanimously, with 38 affirmative votes, that the standard be recommended to the Board of Directors of the Institute for submission to the American Standards Association for approval as American Recommended Practice. This was accordingly done, at the Feb. 1.6, 1932, meeting of the directors, and the American Standards Association approved the standard on July 6; 1.932, designating it as ASA M5-1932.

Jan 1, 1932

The key-note of good writing, as of good manners, is B natural. Sincerity is the first requisite for effective writing. When a man says what he knows or believes, he is likely to be interesting, because each human being possesses an individuality, a point of view, or a range of sympathy that makes him different from his fellows. To say or to write what you do not think, for the mere sake of talking or writing, is a verbal exercise that must be performed with extraordinary skill if it is to be attractive. Affectations are rarely attractive, rarely effective. To be natural is to be yourself, not a poseur; to give the reader the best of yourself, instead of re-warming the baked meats of yesterday. Quotations-which are second-hand thoughts-will serve occasionally when the thing you want to say has been said so well by another that it would be waste of energy to try to say it better; gut, as a rule, the utterance of the writer himself is more interesting than the quotation, because the writer brings something of himself to bear on the subject, and for the moment is more in touch with the reader than any dear departed author. Therefore, say things as best you can in your own way, neither in borrowed words nor in the phraseology that mimics another. Write as if you were speaking to a person whom you desire to persuade or convince. You will then write better than you speak, because, in the first place, you can be more deliberate, and, secondly, you can revise what you have written. Speaking and writing are similar mental acts, with a difference: the difference between eating food raw and eating it cooked. Some kinds of food gain nothing by being cooked; likewise some kinds of utterance are not bettered by being written down first; but most expressions of thought, especially

Jan 1, 1931

By R. C. Ku, A. J. McEvily, T. L. Johnston

The microplastic response of a series ofas-quenched Fe-Ni-C martensites has been measured at 77°K. At strains less than JO'3 the flow stress is governed primarily by the transformation-induced dislocation structure of the martensite. Only at strains in excess of 10-3 is the influence of carbon manifested in the flow stress. At these macroscopic strains, typically 10-2, the solid-solution hardening is proportional to (wt pct C)1/3, and, in an alloy containing 0.39 wt pct C, amounts to 50 pct of the flow stress. THE technological significance of high-strength ferrous martensite has stimulated many investigations of its structure and properties. Although our knowledge of the characteristics of martensite has increased immensely, especially with the advent of high-resolution techniques, an understanding of the basic strengthening mechanism still remains elusive. The purpose of the present paper is to consider certain aspects of micro-plastic behavior of Fe-Ni-C martensite which we feel can help to resolve this important problem. Such alloys are particularly suitable for experimental investigation because their compositions can be adjusted to reduce the M, to a temperature low enough essentially to eliminate the diffusion of carbon in the freshly formed martensite.1 The mechanical properties in this condition are of interest inasmuch as they reflect a state that is free of the important but complicating influence of precipitation processes. In this virgin martensite the carbon is distributed as it was inherited from the parent austenite; i.e., it is present interstitially, and gives rise to tetragonality through strain-induced ordering.' In order to determine the source of strength of such alloys, Winchell and Cohen1 investigated the low-temperature macroscopic stress-strain behavior of a series of virgin martensites of increasing carbon content but of common M, temperature (-35°C). They found that the flow stress increased rapidly with carbon content up to 0.4 wt pct; beyond this point the flow stress increased at a much slower rate. It was concluded that martensite is inherently strong. To account quantitatively for the strength of virgin or as- quenched martensite in terms of the role of carbon, Winchell and cohen3 suggested that the carbon atoms, trapped in their original positions by the diffusionless martensite transformation, interfere with dislocation motion according to a model akin to that of Mott and Nabarro. 4 In this treatment, individual carbon atoms are considered to constitute centers of elastic strain and thereby generate an average stress resisting the motion of dislocations throughout the lattice. The additional stress necessary to move dislocations, over and above that necessary for motion in a carbon-free martensite, is given by where L is an effective length of dislocation capable of motion. L was assumed to be limited to the spacing between the twins that are an essential structural element of Fe-Ni-C martensites. They assumtd the spacing to be invariant and of the order of 100A. However, recent work5 has shown that L is variable and can be in excess of 1000Å, so that the assignment of an appropriate value of L is not straightforward. In contrast to the above conclusion that there is an intrinsically high resistance to plastic flow, it has been suggested by Polakowski6 that freshly quenched martensite is in fact "soft" in the sense that dislocations are initially free to move upon application of stress. The high indentation hardness and macroscopic yield stress of ferrous martensites are then a consequence of rapid strain hardening that depends upon carbon in solution. Consistent with this point of view are the results of Beau lieu and Dubé who measured the rate of recovery of internal friction as a function of aging (tempering) temperature in a freshly quenched steel containing 0.90 wt pct C, 0.37 wt pct Mn, 0.1 wt pct Cr, and 0.07 wt pct Ni. The kinetics were clearly consistent with the idea that many dislocations are unpinned in the as-quenched state and that during aging they become progressively pinned by carbon at a rate controlled by carbon diffusion in the body-centered martensite lattice. In order to provide a basis upon which to distinguish between the "hard" and "soft" interpretations indicated above, we have made studies of the initial stages of plastic deformation in Fe-Ni-C martensites similar to those'used by Winchell and Cohen. It will be shown that the results support the contention that dislocation segments in as-quenched material are indeed

Jan 1, 1967

By Edward D. Peters

IT frequently occurs in the establishment of reduction works, in an entirely new and untried mining district, that the metallurgist in charge finds considerable difficulty in determining the process best adapted to the ores which he receives for treatment. At the first glance it would seem easy enough to decide what style of furnace is best adapted for beneficiating any one class of minerals. If the ore possessed a quartzose gangue and was comparatively free from base metals, while salt could be obtained at a reasonable price, one would naturally resort to a chloridizing roasting, and pan or barrel amalgamation for the extraction of its silver contents. If galena or carbonate of lead was the prevailing mineral, and charcoal could be obtained at moderate figures, the blast-furnace would beneficiate the ores most advantageously. But if, as is usually the case in Colorado, the ores consisted of an intimate mixture of galena, zinc-blende, copper-pyrites, and noble silver minerals, associated with an overwhelming mass of siliceous heavy spar, or limestone gangue, the common reverberatory furnace can be used to the greatest advantage; and, although the product is only a copper matte, I do not hesitate to affirm that it can be treated, and the silver, gold, and copper produced at nearly the same price for which silver and lead can be separated. In Germany, blast-furnaces are frequently used for this same purpose, both for argentiferous and non-argentiferous copper ores ; but any one who will take the trouble to examine the statistics of smelting at Fahlun, the Oberharz, and other Continental works of this description, will see that the expenses are far too great, and the production much too small to think of employing this method in our mining districts, where only the softest and most miserable kind of charcoal is obtainable. I propose in this paper to give an accurate account of the expenses incurred at the Mount Lincoln Smelting Works in treating the same kind of ore, and producing the same end-product in both blast and reverberatory furnaces. I have taken for comparison a favorable campaign of the blast-furnace, and a good average month's running of the reverberatory. In the blast-furnace estimate I have included the calcining and concentration of the matte produced during that campaign, as I always, when possible, concentrated the regulus made

Jan 1, 1874

By J. W. Clark, C. T. Sims

Wrought chromium-base alloys containing yttrium, cubic monocarbides of the Ti(Zr)C type, and similay alloys containing manganese and rhenium have been melted and fabricated. Strength has been studied by hot hardness and elevated-temperature tensile and rupture measurements, low-temperature ductility by tensile testing, and surface stability by oxidation testing. In additiod, studies have been conducted of the carbide stability, and of aging behavior. The carbide dispersion generates effective elevated-temperature strength, which is further enhanced hv strain-induced precipitation. The dispersion exhibits classical dissolution and aging response. The ductile-to-brittle transition temperature of these alloys is above room temperature. The alloys reported show fairly good oxidation resistance, but nitrogen contamination can cause fortnation of a hard Cr2N layer under the oxide scale. Manganese does not appear to be a promising alloying element in chromium. In the years 1945 to 1950, the metal chromium was considered as a possible base for alloy systems due to its considerably higher melting point than superalloys, its low density, its high thermal conductivity, and its apparent capacity for strengthening. However, this interest in chromium was short-lived. It was found difficult to melt and cast, to be exceptionally sensitive to the effect of minor imperfections, to have a lack of ductility at both room and elevated temperatures, and to be subject to a deleterious effect of alloying elements upon the ductile-to-brittle transition temperature.' Since then, chromium, as a practical alloy base, has remained virtually unstudied. Further, purposeful ignoring of chromium has been promoted by statements that its bcc structure would not allow it to be strengthened to useful values, when compared to the "austenitic" alloys.2 Recently, a new look has been taken at chromium-base alloy systems. Study of the literature will show that chromium, providing some of its disadvantages could be eliminated or minimized, actually has a rather attractive potential as an alloy-system base. Analysis of rather scattered data suggests that chromium is quite capable of being strengthened to high levels. Also, significant strengthening of its two sister elements in Group VI-A, molybdenum and tungsten, has been demonstrated in a number of commercial and exploratory alloys. Chromium should be similar. Since chromium does not readily form a volatile oxide like tungsten or molybdenum, it offers a much higher probability of giving birth to alloy systems with useful oxidation resistance. Concerns about possible high elemental vapor pressure have been mitigated by recent data.3 In addition, the physical properties exhibited by chromium are attractive for application as a high-temperature structural material. For instance, its thermal conductivity varies from 49 to 36 Btu-ft/hr-sq ft-°F over its range of usefulness (which is two to four times higher than most superalloys), its density is about 7.2 g per cc (20 pct less than most nickel-base alloys), its coefficient of thermal expansion varies from 4 to 8 x 10-6 per OF, and it has a relatively high modulus of elasticity, approximately 42 x 10' psi.4 Alloying studies on a chromium base in the past have usually encompassed rather sweeping solid-solution alloy additions for strengthening. This is not consistent with contemporary alloying practice in Group VI-A. For instance, molybdenum, also in Group VI-A, is primarily alloyed for strength improvement by use of heat-treatable carbide dispersions.5 Chromium and molybdenum are similar in their chemical activity and other properties. Thus, strengthening of chromium by carbide dispersions was studied. Chromium-base alloys are plagued with room-temperature brittleness, although high-purity unal-loyed chromium can be made ductile.4,8 Use of yttrium as a scavenger has done much to improve ductility and resistance to nitrogen embrittlement in chromium systems,7 so it was utilized in this program. It has also recently been found8 that small rhenium additions (1 to 5 pct) create improvement in the ductility of Type 218 tungsten wire. This is apparently related to the remarkable effect of rhenium additions near its terminal solid solubility in all Group VI-A metals.9'10 Investigation to establish if dilute concentrations of rhenium would also be effective in chromium appeared to be logical for this program. Since rhenium is too expensive to be practical in alloys for application as structural components, ductility improvements through solid-solution alloying were also sought by substitution of manganese for rhenium; manganese, like rhenium, exists in Group VII of the periodic system. The optimum amount of carbide dispersion for chromium-base alloys was obtained by analogy with molybdenum. Strengthening in molybdenum is achieved by use of Ti-Zr carbide dispersions. A

Jan 1, 1964

By K. C. Ten Brink, Allen D. Garrison

A rrevious paper1 reviewed some of the properties of clays and shales and presented some data on the nature of the gelling phenomenon. It included a brief discussion of origin of clays and shales, their composition, structure, retention of water, ionization, base exchange, and the nature of the gelling of water suspensions. Other publications of the Institute2-8 have discussed the properties of clays and their relations to drilling-fluid behavior and control. It is the purpose of this article to present some new data obtained and arranged in a different manner and making possible a better understanding of the chemical reactions involved in the control of drilling-fluid characteristics during the normal drilling operations. Experimental Procedure The difficulties involved in the measurements of the flow characteristics of plastic fluids are too familiar to recite. The possible applications of some of the well-known instruments to this problem have been adequately discussed by Hobson9 and he has given an excellent bibliography. Although there are many viscosimeters of varied design, none of them appear to fulfill the most obvious demands of accuracy in the measurement of clay or shale suspensions. Since the fluid characteristics are dependent on the rate of flow of the fluid, and the viscosity usually falls off very rapidly as the rate is increased, it is clear that the first requirement is that the instrument shall be capable of a wide variety of speeds. The viscosity of the fluid at any fixed and constant rate of flow is also a function of time, so that the second demand is that the instrument shall be capable of a constant and continuous motion for a prolonged period of time.

Jan 1, 1940

By K. C. Ten Brink, Allen D. Garrison

A rrevious paper1 reviewed some of the properties of clays and shales and presented some data on the nature of the gelling phenomenon. It included a brief discussion of origin of clays and shales, their composition, structure, retention of water, ionization, base exchange, and the nature of the gelling of water suspensions. Other publications of the Institute2-8 have discussed the properties of clays and their relations to drilling-fluid behavior and control. It is the purpose of this article to present some new data obtained and arranged in a different manner and making possible a better understanding of the chemical reactions involved in the control of drilling-fluid characteristics during the normal drilling operations. Experimental Procedure The difficulties involved in the measurements of the flow characteristics of plastic fluids are too familiar to recite. The possible applications of some of the well-known instruments to this problem have been adequately discussed by Hobson9 and he has given an excellent bibliography. Although there are many viscosimeters of varied design, none of them appear to fulfill the most obvious demands of accuracy in the measurement of clay or shale suspensions. Since the fluid characteristics are dependent on the rate of flow of the fluid, and the viscosity usually falls off very rapidly as the rate is increased, it is clear that the first requirement is that the instrument shall be capable of a wide variety of speeds. The viscosity of the fluid at any fixed and constant rate of flow is also a function of time, so that the second demand is that the instrument shall be capable of a constant and continuous motion for a prolonged period of time.

Jan 1, 1940

By S. Nakajima, H. Okazaki

Quantitatiue studies of the deformation texture in drawn tungsten wives were made by the X-vay dif-fractottletetr. Experimental results show that the diffraction Intensities are equal to tilose pvedicted from the (1 10). fiber lexlure but the angxla), spreads of. diffraction peaks in the pole distribution curres are different for different diffraction planes and directions. For this reason a modified (110) fiber lextuve model, in which a kind of anisotropy is assumed, is proposed to explain the results. According to this model the poles lying on a line directing front the (110) to the (110) poles in the (1 10) standard stereograpllic projection should show spreads which are different from those lyitlg on a line directing from the (001) to the (001) poles, which is confirmed by the experiments. The anisolvopy and the spveads of the pole positions are large at the outer part of the wires and decrease gradually lowards the inside of the wire. The possibilily of occurrence of such anisolropy in irrelals with fcc stvuctures is discltssed. THE deformation texture of drawn tungsten wires has been assumed by different investigators to be the simple ( 110) fiber texture.' Recently, however, Leber2,3 has shown that a swaged tungsten rod has a cylindrical texture. It changes gradually to the (110) fiber texture by drawing through dies. However, even after drawing to 0.25 mm in diam, the cylindrical texture can still be found in wires together with the (110) fiber texture. This was deduced from the pole figures obtained from the longitudinal section of these wires. Use was made also of quantitative measurements of the pole distribution curves. Leber stated that the angular spread of the pole distribution curves (henceforward called dispersions) are quite different for (400) 45 deg and (400) 90 deg: the former is always larger than the latter. This inequality is accompanied by deviations of the diffraction intensities from the theoretical values for the ( 110) fiber texture. Bhandary and cullity4 have reported similar results on iron wire and explained them by assuming a cylindrical texture. Both Leber3 and Bhandary4 used only the results of the (400) reflection for the determination of the dispersion. The pole figures found by Leber3 and by Rieck5 are largely different. The model given by Leber to explain the effects is in the authors' opinion in some respects unsatisfactory, especially if one looks at other than the (400) reflections. Intensities and dispersions of diffraction peaks are conclusive factors for the determination of the fine structure in wire textures. For this reason we studied them extensively to come to a model which is more suitable to fit the facts. In the following, after giving the experimental set-up, we report about measurements of X-ray diffraction on drawn tungsten wires. Different models to describe the experimental results will be discussed. EXPERIMENTAL GO-SiO2-A12O3 doped tungsten wires drawn to 0.18 mm in diam were used for the measurements. The wires were chemically etched to various diameters down to 0.03 mm. Measurements were carried out for the different wires in order to determine the dependence of the texture on the radius. The wires were cut to pieces of 10 mm length and fixed with paste closely against each other on a flat, polished glass plate. Parallelism of the wires with the surface of the glass plate should be adequate. For the diffraction studies three different X-ray sources were applied, respectively, giving the CuK,, FeK,, and FeKp emission. The measurements were carried out with a diffrac-tometer with a GM counter. The latter was fixed to a certain diffraction angle 20hkl and the diffraction intensity was recorded as a function of the angle of rotation of the specimen around the axis, lying in the specimen surface and perpendicular to the wire axis, as shown in Fig. 1. Measurements were also done with the detector at angles slightly deviating from the diffraction maxima The measured intensities in this case were taken to be equal to the background level. The deviations were chosen as small as possible but large enough to eliminate the influence of the diffraction maxima. The useful range of the rotation angle x of the specimen is generally limited by the wavelength of the X-rays. We have: where and cp is the angle between the wire axis and the normal of the diffraction plane. Intensity measurements were made to find the necessary corrections for counting loss of the GM counter and for distortion resulting from such effects as absorption of X-rays and from inclination of the reflection plane under study with respect to the surface of the specimen. The counting loss was esti-

Jan 1, 1968

By W. S. Hyler, W. L. Bruckart

The powder metallurgy and arc-cast types of wrought molybdenum stock were studied in rotating beam fatigue. Endurance ratios of unnotched specimens after 5x10 cycles were found to be 0.74 and 0.81, respectively. Fatigue notch factors (K,) of 1.36 and 2.05, respectively, were obtained on V-notched specimens having a theoretical stress-concentration factor Kt = 3.1. MOLYBDENUM and its alloys are rapidly gaining importance as engineering materials of construction for high temperature applications. AS a wrought material, molybdenum and its alloys are outstanding above 1800°F. It is necessary, however, with molybdenum to provide elevated temperature oxidation protection. This is currently being studied by a number of investigators. Thus far, there have been no published data on the fatigue behavior of molybdenum either at room temperature or at elevated temperature. The knowledge of fatigue behavior, particularly notched fatigue behavior, becomes increasingly important as the engineering importance of a material increases, especially from the design standpoint. The work described here was directed toward determination of the notched and unnotched rotating beam fatigue characteristics of molybdenum at room temperature. Also, it was desired to learn whether any difference exists between wrought molybdenum of the powder metallurgy and the are-cast types. Fabrication History of Bar Stock For this work, bar stock was procured from Climax Molybdenum Co. (are-cast type) and from Westing-house Electric Corp. (powder metallurgy type). The processing histories of these materials are listed in Table I. The first lot of are-cast molybdenum was deoxidized by aluminum additions. The second lot was deoxidized by carbon." Both lots of the powder Microstructure A microscopic examination of these materials, as received, revealed the powder metallurgy molybdenum to be free of inclusions and to be finely fibered. On the other hand, the are-cast C molybdenum possessed numerous carbide inclusions, and the arc-cast A appeared to have coarse grained fibers. These are shown in Fig. 1. Owing to the large apparent difference in fineness of fiber between the are-cast A and the powder product and are-cast C, a check was made of the recrystallized grain sizes to determine whether these differences persisted. A series of recrystallization anneals revealed mixed grain sizes in both the are-cast A and the powder product. Variations in grain diameter of as much as 50 times were found after full recrystallization at 1200°C for 30 min. There was no distinction between the two. Arc-cast C was not checked. Room Temperature Mechanical Properties Prior to subjecting the materials to fatigue tests, room temperature mechanical properties were determined. These data, together with the tensil: strength of the notched bars, data,togetherare listed in Table tensil: There were no significant differences in the tensile strengths of the two types of molybdenum. However, the powder metallurgy material was generally more ductile and yielded at a somewhat lower stress than the arc-cast material. Tensile strengths of the notched specimens indicated a slightly greater notch strengthening effect in the are-cast C than in the powder product, lot 2. Room Temperature Fatigue Properties Sample Preparation: Specimens were prepared for use in R. R. Moore rotating beam fatigue machines. These specimens had a continuous radius test section with a minimum diameter of 0.260 in. The specimens were prepared by grinding to shape and polishing to produce a smooth unworked surface. Polishing consisted of rotating a disk in the continuous radius section on which were attached, successively, emery belts of 240, 400, and 600 grit. The specimens were slowly rotated during the operation. The belt speed was high, and rotation was such that polishing scratches were longitudinal. Unnotched Fatigue Properties: Unnotched fatigue data were obtained from a number of specimens of each of the four lots of molybdenum. The results of the tests are presented in Fig. 2. From this figure,

Jan 1, 1956

By K. G. Wikle, J. G. Klein, W. W. Beaver

Consolidation of hydride process, electrolytic, calcium reduced, and comminuted thorium powder, as well as saw chips and lathe turnings, by vacuum hot pressing and by cold pressing-vacuum sintering was studied. The mechanical properties of the consolidated material in the extruded form are compared with those of wrought castings. AT present there little little industrial use for thorium metal, although it has some important though small scale applications in electronic equipment. Despite its high inelting point—about 1750°C —a low modulus of elasticity, 11.4xl0 si at 20°C;' relatively low mechanical properties coupled with a high density, 11.7 g per cu cm; and an unusually high chemical activity with normal atmospheres limit any structural applications. The metal is utilized as an alloying element principally in magnesium. Pure thorium finds utility as electrodes in gaseous discharge lamps such as the high intensity mercury lamp' because its low work function and high electron emissivity provide lower starting potentials and more uniform operating characteristics than other available materials. The metal is also found in photoelectric tubes used for the measurement of the ultraviolet spectrum." Thorium metal has been used in germicidal lamps of the cold cathode type as sputtered coatings on nickel in order to provide a low work function surface and a low starting voltage. Other applications have involved the radioactive properties of thorium for the production of ionized particles." The potential value of thorium is much greater than its present use pattern because of possible utility in the field of nuclear power. Th may be converted through nuclear reaction to a fissionable element U which should be capable of acting similarly to U in the g'eneration of atomic power. Thorium has been reported to be about three times as plentiful as uranium in the earth's crust, placing it in the order of abundance of lead and molybdenum." Thus, it is of interest in augmenting the potential supply of fissionable material for nuclear power. Because of its high melting point, thorium is usually produced as a powder through the calcium reduction of its oxide or thermal reduction of halides by sodium, magnesium, and calcium. It may also be produced in flake form by electrolysis of fused alkali or alkaline earth chloricles and fluorides. Therefore, powder metallurgy assumes importance in the fab- rication of thorium metal shapes. Furthermore, it is rather difficult to obtain pure thorium by melting, as the molten metal reacts readily with graphite as well as oxide, carbide, and nitride refractories. These contaminate the melt with oxides, carbides, and metallic impurities." The current investigation was undertaken to examine the fabrication of thorium by powder metallurgy methods which have been used for the commercial production of beryllium and other metals.' A sparcity of data concerning the comparative cold and hot compaction of thorium powders of different derivation existed. Therefore, all commercially available types were examined along with other experimentally produced thorium powders in order to round out the comparison of consolidated thorium powders with melted reguline metal. Review of the Literature By heating a mixture of ThC1, with potassium, Berzelius made the first thorium metal as an impure powder in 1828. Improvements in the basic process, increasing thorium assay to 99 pct, were made by several investigators including Arsem," Lely and Hamberger10 and Von Bolton." Calcium reduction of Tho, to make powders was investigated by Berger," Huppertz,'" Kroll," and Kuzel and Wedekind.'" A thorium powder produced by this method using a CaC1, fluxing agent assayed 99.7 pct, as reported by Marden and Rentschler.'" Compacted and sintered, this product was found to be ductile, and could be fabricated into wire and sheet. Improvements of the calcium reduction process were made later" wherein CaCl, was eliminated from the reaction, producing metal assaying 99.8 pct Th. Further work by Lilliendah118 howed that a coarser metal could be obtained by the substitution of ThC1, or ThOC1, for oxide with consequent advantage of stability to atmospheric reaction. Reports on the technology of thorium developed in Germany during World War II have been made by Espe."' Thorium powder of 99.5 pct Th was obtained by reduction of the oxide by calcium. Screening to —200 mesh, compacting with about 20 tsi, and sintering in vacuo at 1320" to 1360°C for 3 hr resulted in a porous sinter cake. The sinter cake was sufficiently ductile to be worked into bar, wire, and sheet which could be employed as electrode materials.

Jan 1, 1957

By A. S. Richardson

AIR conditioning, or air cooling, for the improvement of ventilation in the Butte mines has come into increasing use during the past 10 years. In part, the methods practiced have been described in previous publications of the Institute, but some improvements on earlier methods have been made and a number of new features have been developed. This paper is presented as a record of progress made, and for the sake of completeness describes all general features of the work. The need for air conditioning in the ventilation of mines in the district arises from the fact that the temperature of the ground and mine water has shown a very great increase with increase in mining depth, and has now reached a maximum of slightly over 130ºF. The most difficult part of the ventilation problem is the maintenance of temperature and humidity of a satisfactory standard in the working places, especially on the lower levels. Although ordinary ventilation is adequate to maintain good conditions in most of the working places it is subject to a number of limitations at great depth. Most important among these limitations is that with increase in depth the air becomes heated before it reaches the working places, both by compression from increase in atmospheric pressure and by heat transferred to it from rock at high temperature, so that its capacity for lowering temperatures is greatly reduced before it reaches the operating zone. Increasing depth of mining also increases the distance traveled by the air in its passage through the mine, and this causes a corresponding increase in resistance to air flow, so that there is greater difficulty in maintaining even the same volume in circulation. Thus, in the face of a demand that the ventilating system have a very much greater capacity to remove heat from the mine, the tendency is for that capacity to diminish. The only evident alternatives were (I) the opening of additional air shafts to increase the volume of air in circulation, (2) an extension of the existing system that would be subject to the same limitations, or (3) the adoption of an entirely different method such as air cooling. Fortunately for an economic solution of the problem, the mean annual temperature of the surface atmosphere at Butte is about 40°F., with very low relative humidity in summer, so that there is unlimited natural cooling power at a temperature range adaptable to air-conditioning methods. METHODS Two similar methods of air conditioning are used, as necessitated by service requirements and dependent upon the equipment available. In one, which is the more important and has the greater cooling capacity, water is circulated in a closed circuit, and, alternately, first absorbs heat from warm mine air and then dissipates it in the surface atmosphere by cooling at a cooling tower. The second

Jan 1, 1941

By F. W. Steadman, Charles S. Barrett

Deformation bands of surprising regularity are found in large-grained poly-crystalline copper after cold-rolling (Fig. I). Individual bands frequently are large enough to permit a determination of their orientation by means of etch pits and an optical goniometer. Measurements have been made on 21 areas in seven different grains, and these, combined with X-ray studies of nine single crystals that had been cold-rolled after mounting in a polycrystal-line block, have contributed to a better understanding of the preferred orientations in rolled copper just as similar studies have for rolled iron1 and brass.2,3 Particular attention was given to determining orientations that are stable during rolling and to the manner of fragmentation and rotation of unstable grains. The possible role of twinning was also carefully investigated. The texture of polycrystalline copper after cold-rolling is well established by the pole figures that have been plotted by Schmid and Staffelbach,4 Iweronowa and Schdanow,6 and Brick and Williamson,8 all of which are in substantial agreement. There has been some divergence in the list of individual "ideal" orientations that have been used to describe the texture by these observers and others," although the orientation (110) [II2]—that is, (110) parallel to the rolling plane and [TIP] parallel to the rolling direction—is generally recognized as the most prominent orientation and (112) [III] one of the lesser orientations. Other orientations have been given by some observers as (236) [535], (100) [00I], and (110) [00I]. The texture of copper has also been described as (I35) [533].6,7 The sum of these orientations provides a reasonable approximation to the complete pole figure, but it does not follow that these specific orientations are necessarily of fundamental significance, for the choice of indices is arbitrary, within limits. Furthermore, a detailed investigation of the ideal orientations in cold-rolled iron discloses continuous ranges of equally favored positions rather than definite positions of high stability,' and similarly Brick's observations in a single crystal of a brass2 suggest that all orientations in the range between (110) [II3] and (110) [II7] are about equally stable. Materials and Methods The material used was vacuum-cast electrolytic copper kindly supplied by L. L. Wyman, of the General Electric Co.* Slicec 1/2 in. thick and 21/2 in. square, cut from the ingot, were rolled with 50 per cent reduction per pass to final thicknesses between 0.02 and 0.04 in., and etched to develop cube-face etch pits suitable for goniometric work.8 The etch was light on some strips and deep in others.

Jan 1, 1942

By Charles S. Barrett, F. W. Steadman

Deformation bands of surprising regularity are found in large-grained poly-crystalline copper after cold-rolling (Fig. I). Individual bands frequently are large enough to permit a determination of their orientation by means of etch pits and an optical goniometer. Measurements have been made on 21 areas in seven different grains, and these, combined with X-ray studies of nine single crystals that had been cold-rolled after mounting in a polycrystal-line block, have contributed to a better understanding of the preferred orientations in rolled copper just as similar studies have for rolled iron1 and brass.2,3 Particular attention was given to determining orientations that are stable during rolling and to the manner of fragmentation and rotation of unstable grains. The possible role of twinning was also carefully investigated. The texture of polycrystalline copper after cold-rolling is well established by the pole figures that have been plotted by Schmid and Staffelbach,4 Iweronowa and Schdanow,6 and Brick and Williamson,8 all of which are in substantial agreement. There has been some divergence in the list of individual "ideal" orientations that have been used to describe the texture by these observers and others," although the orientation (110) [II2]—that is, (110) parallel to the rolling plane and [TIP] parallel to the rolling direction—is generally recognized as the most prominent orientation and (112) [III] one of the lesser orientations. Other orientations have been given by some observers as (236) [535], (100) [00I], and (110) [00I]. The texture of copper has also been described as (I35) [533].6,7 The sum of these orientations provides a reasonable approximation to the complete pole figure, but it does not follow that these specific orientations are necessarily of fundamental significance, for the choice of indices is arbitrary, within limits. Furthermore, a detailed investigation of the ideal orientations in cold-rolled iron discloses continuous ranges of equally favored positions rather than definite positions of high stability,' and similarly Brick's observations in a single crystal of a brass2 suggest that all orientations in the range between (110) [II3] and (110) [II7] are about equally stable. Materials and Methods The material used was vacuum-cast electrolytic copper kindly supplied by L. L. Wyman, of the General Electric Co.* Slicec 1/2 in. thick and 21/2 in. square, cut from the ingot, were rolled with 50 per cent reduction per pass to final thicknesses between 0.02 and 0.04 in., and etched to develop cube-face etch pits suitable for goniometric work.8 The etch was light on some strips and deep in others.

Jan 1, 1942

By Ravindra M. Nadkarni, Milton E. Wadsworth

The kinetics of cetnentation of copper with iron were observed to follow first-order kinetics and increase with speed of agitation to a limiting value. Maximum rates agree closely with theoretical values based upon a model of aqueous solution diffusion through a litniting boundary film. Back reaction kinetics are shown both theoretically and experimentally to be independent of ferrous iron concentration in solution. The inlportance of attnospheres of air, oxygen, nitrogen, and hydrogen was studied and the results have been correlated with several impovtant oxidation processes involving metallic iron and copper. The kinetics of the reaction of ferric ion with metallic iron were found to be slow in the absence of metallic copper and essentially proportional to the surface area of metallic copper present in the system. THE precipitation of copper on iron is classic as an example of a relatively ancient art applied successfully for centuries with little fundamental understanding of the important parameters involved. There is some indication that the process has been a commercial means to produce copper since the sixteenth century.' The amount of fundamental work on the cementation of copper with iron is not great. Wartman and Roberson2 carried out a series of detailed copper cementation experiments using natural and synthetic mine water. The following were presented as the three principal reactions: Reaction [I] is the desired cementation reaction and accordingly 0.88 lb of iron would produce 1 lb of copper. In actual practice iron consumption would more normally fall in the range of 1.5 to 2.5 lb per lb of copper. Wartman and Roberson attributed the excess consumption of iron to Reactions [2] and [3]. They found that Reactions [I] and [2] proceeded at approximately the same velocity while Reaction [3] was much slower and would be diminished by controlling the contact time. It was also pointed out that increased agitation is beneficial in removing hydrogen bubbles and barren layers of solution at the iron surface as well as removing contaminants resulting from the hydrolysis of iron. Episkoposyan3 and Episkoposyan and Kakovskii4 studied copper and silver cementation on rotating iron disks in chloride solutions. The kinetics based upon a diffusion model were first order and varied linearly with surface area and with angular velocity raised to the one-half power according to the Levich equation. The experimental activation energy for both copper and silver was approximately 3 kcal per per mole. Excess iron consumption was found to increase with temperature. The rate of cementation first increased with increasing acidity and then diminished at high acid concentrations. sutolov5 has presented an excellent review of the Leach-Precipitation-Flotation (LPF) process including a discussion of copper cementation from an electrochemical point of view although few experimental results were presented. From voltage considerations he predicted that cementation should not be influenced by the concentration of ferrous iron in solution. He considered several secondary reactions including Reactions [2] and [3] and pointed out the importance of oxidation of ferrous iron to ferric with oxygen. In addition it was suggested that Reaction [2] was enhanced by the dissolution of metallic copper by ferric iron which in turn consumed excess iron by the cementation reaction, Eq.[1]. Cementation of copper on metals other than iron has been studied by several investigators but, as in the case of iron, the amount of fundamental work is not extensive. Bashkova and kovalenko6 and Bashkova7 studied the cementation of copper on indium from copper and indium sulfate solutions. The rate was found to be first order and to increase with acidity. This was associated with a decrease in potential (EIn — ECu) and the simultaneous reduction of hydrogen ions at low pH. The rate of cementation also decreased with increasing indium concentrations which was postulated to be due to the decrease in the rate of diffusion of the ions in solution. Below 97°C the experimental activation energy was found to have the unusually low value of 2 kcal per mole and was attributed to diffusional control. Above 97°C the rate increased suddenly and was explained as a change in the rate-controlling step to a chemical reaction. In Part I of this study Nadkarni et a1 .1 have reported on preliminary results obtained in a laboratory study of the kinetics of the cementation process. The rate was found to be first order, proportional to the surface area of the iron, and to increase with speed of stirring until a maximum rate was observed. At low stirring speeds the deposit was spongy and adherent. At medium speeds the copper peeled off in bright strips and at high speeds finely divided copper was produced and continually removed from the surface. The amount of excess iron consumed increased with speed of stirring and with temperature. The average experimental activation energy combining results from several types of iron was 5.8 + 1.6 kcal per mole suggesting diffusional control through a limiting boundary film. Traditionally copper cementation has been carried out over the centuries in gravity-fed launders of various design containing scrap iron. More recently rotating drum precipitators and activated launders8'10 have been used. In the latter, copper-bearing solutions are

Jan 1, 1968

By Robert R. Brookshire

Brush plating has been thought of by many as black magic bordering on alchemy. Actually it is a science that uses both electro-chemical and mechanical engineering skills and technology. We are not sure when brush plating was first used or by whom. I do know that many times when we would put in for patents on things we thought of as new and innovative, we would find that someone had done it many years before. It took World War I1 to get brush plating off and running. Now at this point, someone may be asking just what is brush plating? And why are we plating brushes? One way of describing what brush plating is, is by telling what it is not such as tankless plating. Brush plating-is an electro deposition of an electro-platable element or alloy onto a conductive surface. To do this a source of direct current is required; this can vary widely. I prefer stepless voltage control from 0-35 volts with a capacity depending on the size job to be done. This can vary up to 500 amps for normal applications. In one case we have used 7500 amps.. In the beginning a brush was actually used with a wire in the middle of the bristles and a jelly-like paste made up from tank plating solutions. The bristles were saturated with the gunk and the spot to be plated was muddled with the concoction at a potential which was the same as the applied tank Voltage. Metal was deposited but only thin coats were achieved. Today we use graphite wrapped or covered with cotton to form a Q-tip type anode. By using graphite rather than a specific metal we are able to either plate, de-plate or strip, electro- mill, electropolish, or anodize--all with the same equipment. Only the electrolyte needs to be changed.

Jan 1, 1984

By L. W. Pommier, F. B. Brien, A. K. Bhasin

The diflerential movement of solid particles through solid-liquid suspensions is very important to many branches of engineering. The flow of suspensions around immersed bodies is mainly of a turbulent nature. Problems are encountered when attempts are made, as is the general practice, to extrapolate the velocity and resistance relationships of Newton, pertaining to Newtonian systems, into non-Newtonian solid-liquid suspensions. The conventional velocity and resistance relationships for turbulent flow in fluids when applied to suspensions, do not take into consideration the two very important variables: suspension particle size and solid volume fraction. A study of the effect of suspension particle size (dgb) on the velocity of falling balls leads to the concept of a critical particle size (dgc) at which the suspensions will be Newtonian. This leads to the classification of static suspensions into two types: suspensions consisting of particle of diameter dgh > dgt, and those with dgh, < dgr. Separate velocity and resistance equations for these two types of suspensions have been proposed, taking into account both the solid particle size and solid volume fraction. The agreement between the velocities predicted from the proposed equations and the measured velocities, confirms their validity. The resistance force offered by suspensions to the movement of immersed bodies has been calculated from the proposed equations, and the effects of suspension particle size and solid volume fraction on the resistance force and velocity have been examined. The movement of immersed bodies in solid-liquid suspensions is of great importance in many areas of engineering such as minerals processing, oil well drilling, suspension flow in pipelines, and hydrometallurgy. A number of mineral dressing processes deal essentially with the movement of solids in suspensions—in particular, classification, thickening, filtration, ore washing, and gravity concentration—thus a study of the fluid characteristics of suspensions is of theoretical and practical interest.&apos; A rigorous analysis of the mechanisms of momentum transport of a solid-liquid system is complex indeed. The rheological properties of the suspensions deviate from those of liquids, varying, for example, with density, solid volume fraction, size and shape of the solid phase of the suspension, and with the density and viscosity of the liquid phase. The flow of suspensions around immersed bodies is mainly of a turbulent nature and hence studies of the turbulent flow characteristics of suspensions are of par- ticular importance. Problems are encountered when attempts are made to extrapolate the velocity and resistance relationships of Newton, pertaining to Newtonian systems, into non-Newtonian solid-liquid suspensions. Due to the numerous variables present in a suspension, certain limitations and assumptions become necessary in order to produce quantitative relationships for predicting their effects. The solid particle size and the solid volume fraction are two of the more important variables. By comparing the measured and calculated Newtonian velocities of falling balls in simple static suspensions, the existing velocity and resistance relationships have been modified to take these variables into account. In order to keep the study less complex, all other variables such as the characteristics of suspending liquid and shape of the particle are maintained constant. Objective The objective of the present investigation is to modify the Newtonian velocity and resistance equations in order to take into account the suspension particle size and solid volume fraction. Theory Liquids are classified on the basis of viscosity, which may be defined as the relationship between applied shear stress and resulting rate of shear.&apos; pure single-phase fluids composed of small light molecules behave as Newtonian liquids, having a single viscosity pa-

Jan 1, 1971