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PENNSYLVANIA ANTHRACITE LOCAL SECTION On Saturday evening, Jan. 31, 1914, about 40 members of the Institute met at the Hotel Sterling, Wilkes Barre, Pa., for the purpose of discussing plans for the formation of a local section in the Pennsylvania anthracite region. President Rand; Prof. Joseph W. Richards, of the Board of Directors; Dr. H. M. Chance, Chairman of the Committee on Coal and Coke, and Secretary Stoughton were among the guests present. R. V. Norris acted as Master of Ceremonies, and the arrangements were all made in advance by a Committee under the leadership of Charles Enzian, to whom an enthusiastic vote of thanks was accorded at the dinner. An address was made by President Rand, followed by .Professor Richards, who outlined the procedure necessary for the formation of a Local Section. Addresses were then made by W. J. Richards, F. W. Chase,. C. F. Huber, R. J. Foster, F. A. Hill, H. M. Chance, Bradley Stoughton, and others, after which a rising vote was taken, and it was unanimously decided to petition the Board of. Directors for the establishment of the Pennsylvania -Anthracite Local Section. More than the required number of members then signed -the petition, and President Rand announced the appointment of a Committee to organize the Section and arrange for a meeting in accordance with their By-Laws, consisting of R. V. Norris, W. J. Richards, R. J. Foster, Edwin Ludlow, C. F. Huber, Charles Enzian, Douglas Bunting, F. A. Hill, and J. M. Humphrey.

Jan 2, 1914

By T. M. Morris

R. T. Hukki (Finland Institute of Technology, Helsinki, Finland)—Two schools of thought are developing concerning the order of the rate of flotation. The paper by Morris is intended to show experimental evidence in favor of the first order rate. Arbiter, on the other hand, has presented an earlier paper" to demonstrate the validity of the second order rate equation. Unfortunately his method of plotting is open to criticism, as pointed out by Morris." A more sensitive method of plotting has been described by the writer,= whereby the data presented by Arbiter demonstrate the superiority of the second order plot. The general rate equation may be written in the following forms for the integrated first and second order equations: (A) t = -1/k In Co-R/Co (first order) [4] 1 (B) 1/t = - kCo + kCo2 1/R (second order) As a first approximation the value of Co may be taken as a unity, 100 pct or 1. Whether or not this is the case in all tests performed by Morris is impossible to judge, owing to the fact that the flotation times are extremely short, e.g. 150 sec in tests A. It would, indeed, be very interesting to know what the total recovery R would be after 1 hr of flotation, for example, instead of after 150 sec. Certainly there are circumstances when C, approaches unity within a very small margin of error. Morris has used the same approximation in his example D "since the feed to this cleaner

Jan 1, 1954

By L. G. Austin, R. R. Klimpel

This communication points out that serious errors exist in some current treatments of the random fracture of solids, including the prior treatments by Klimpel and Austin, Gilvarry, and Gaudin and Meloy. The problem considered in all of these papers is: what cumulative weight versus size distribution is expected for the fragments produced by fracture of a particle? The basic assumption made is that fracture surfaces propagate in random directions from weak flaws in the solid (these weak flaws being activated to fracture by applied stress), with the activated weak flaws distributed at random spatially within the solid. The previous treatments considered fracture in three dimensions, and all use similar physical models, although the mathematical techniques were somewhat different. We first noticed that these treatments were in error when we attempted to reduce the equations developed to the simple case of fracture of a one-dimensional particle, e.g. a long, thin fiber which breaks along its length. For this simple case, it is readily shown that the assumption of random fracture leads to the expression P(V) = (r/Vo) (1-V/Vo) r-1 dV (1) is the probability of occurrence of a fragment of length within the range V to V + dV; V being length dimension, from r random fractures passing through an original size of Vo to produce r + 1 fragments. This equation agreed with the one-dimensional form of an equivalent equation in the original Klimpel-Austin treatment. However, in this treatment it was then stated that, "The fractional weight below size V is [ ]

Jan 8, 1968

By Gordon S. Duncan

(New York Meeting, February, 1912 THE U. S. Geological Survey, I believe, has almost completed a study of the Harney Peak quadrangle, preliminary to the publication of a report on that, district. As I was engaged for some months on an investigation of the mode of occurrence of the ore-bearing formation in this area, it has seemed to me timely to make public the results of my study, as a contribution to the consideration of this subject. It seems scarcely necessary to describe the locality and general geology of the Black hills of South Dakota, for since 1846 many have contributed information concerning this region, some of the reports bearing such well-known names as those of Walter P. Jenney, Henry Newton, S. F. Emmons, and C. R. Van Hise, while we have only to glance at Bulletin No. 4 of the South Dakota School of Mines, in which Prof. C. C. O'Harra, of that institution, has given us a bibliography of contributions to the geography and geology of the section, to find that other well-known men have studied the district, and have given us the benefit of their researches. The U. S. Geological Survey has made geological maps of nearly the whole of the Black hills, the only quadrangle yet to be completed being, as stated, the Harney Peak district. During the late summer and autnmn of 1910, it was my lot to examine and report. on a considerable area in this neighborhood, which once had been prospected, and in some cases exploited, for tin. This paper gives an account of certain geological phenomena, noted at that time, which greatly influenced my conclnsions. The predominating formation of the district is pre-Cambrian, represented by a highly-cleaved mica-schist, usually very garnetiferous, and sometimes hornblendic. Rising like an island from the surrounding schist is a large mass of granite, known as

Jul 1, 1912

By Frank C. Greene

The wildcatting in northern and northwestern Missouri, which started in 1939, was continued in 1940. Two new gas fields were found and one discovered in 1939 was further extended. The total number of completions was 94, of which 5 were oil wells with about 48 bbl. initial production, 30 were gas wells with an initial open-flow capacity of 37,655,000 cu. ft., and 59 were dry holes. The outstanding discovery was the Polo gas field, T. 55 N., R. 28 and 29 W., in Caldwell County. A sand now believed to be a lens in the Bandera shale at a depth of 400 ft. yielded flows of more than 12,000,-000 cu. ft. In all, I0 wells with 31,490,000 cu. ft. of gas, were drilled. The rock pres-sure is 80 lb. At present no arrangements for an outlet have been made. In Platte County, the Prairie Point gas pool in sec. 7, T. 51 N., R. 33 W., and sec. 12, T. 51 N., R. 34 W., and the Lake-side pool in sees. 5 and 6, T. 50 N., R. 33 W., were further developed, and in the latter both oil and gas have been found, but data are not available for publication at this time. Drilling for gas continued in proven areas in Clay County, and for both oil and gas in proven areas in Jackson and Cass Counties. Table 1 summarizes the results of drilling in Missouri in 1940.

Jan 1, 1941

By Frank C. Greene

The wildcatting in northern and northwestern Missouri, which started in 1939, was continued in 1940. Two new gas fields were found and one discovered in 1939 was further extended. The total number of completions was 94, of which 5 were oil wells with about 48 bbl. initial production, 30 were gas wells with an initial open-flow capacity of 37,655,000 cu. ft., and 59 were dry holes. The outstanding discovery was the Polo gas field, T. 55 N., R. 28 and 29 W., in Caldwell County. A sand now believed to be a lens in the Bandera shale at a depth of 400 ft. yielded flows of more than 12,000,-000 cu. ft. In all, I0 wells with 31,490,000 cu. ft. of gas, were drilled. The rock pres-sure is 80 lb. At present no arrangements for an outlet have been made. In Platte County, the Prairie Point gas pool in sec. 7, T. 51 N., R. 33 W., and sec. 12, T. 51 N., R. 34 W., and the Lake-side pool in sees. 5 and 6, T. 50 N., R. 33 W., were further developed, and in the latter both oil and gas have been found, but data are not available for publication at this time. Drilling for gas continued in proven areas in Clay County, and for both oil and gas in proven areas in Jackson and Cass Counties. Table 1 summarizes the results of drilling in Missouri in 1940.

Jan 1, 1941

By H. H. Campbell

The following paper deals almost exclusively with the results of practice at the works of the Pennsylvania Steel Company at Steelton, Pa. From the records of the furnaces at this plant, both acid and basic, large and small, are drawn the data for the various demon strations, and on a long and intimate experience with their opera tions are founded many theories and generalizations. It may seem that universal laws should not be built upon a basis so restricted ; but in reality the condition is the strongest guarantee of validity. Each table investigates some- certain variable, and by virtue of the common origin of the factors, we have good ground for assuming the corresponding agents to be equal. The examples may or may not be instances of good practice, and may be open to criticism if regarded solely as exponents of • metallurgical success. But it must be remembered that the lists are not made up of selected specimens, nor are they chosen to show su perior results; they are gathered to investigate, by strict scientific methods, the formula? of the operation. In such work no untoward results should be eliminated, save those which bear upon their face the stamp of experimental error. If the worst members be omitted, then the best must also be omitted. Only by using every available case can an honest attempt be made to deduce a true average. It is recog nized, however, that with the most careful selection it is difficult, if not impossible, to collect data representing universal conditions. In each table the records tell of a special practice, and all conclusions drawn from them are true only within the limits between which the equations have been integrated. Not assuming the prerogative of speaking for American melters in all the opinions herein expressed, nor acting as a camera in por traying an ephemeral state of national metallurgical development,

Jan 1, 1894

By Albert Sauveur

As THE years go by, names of distinguished metallurgists will be added to the list of Henry Marion Howe lecturers, and now and then an illustrious one, for to be chosen to deliver the Howe lecture will be, I do not hesitate to predict, a highly coveted honor. I pray, therefore, your indulgence, if I confess to a feeling of gratification in having been appointed the first of these lecturers. It does not follow, however, that I am losing all sense of proportion and that I have an exaggerated idea of the little I have been able to contribute to our knowledge of iron and steel. Indeed, I fully realize how small were my claims to so great a distinction. I realize, also, that those entrusted with the task of selecting a lecturer were actuated, in coming to a decision, by their knowledge of the long and intimate friendship that had existed between the leader we have lost and myself. For their generous impulse, I thank them from the bottom of my heart; and with becoming modesty, I take up my task as the first Henry Marion Howe lecturer. It would be pleasant and indeed most appropriate to devote this entire lecture to a eulogy of Henry Marion Howe and his work, but how short the time for so large an undertaking and how inadequate my qualifications! On Aug. 28, Sept. 4, 11, and 18, 1875, a series of articles appeared in the Engineering & Mining Journal entitled "What is Steel?" With one exception, these constitute the first professional paper of Henry Marion Howe. That was nearly fifty years ago, three years after graduating from Harvard University. He was then but twenty-seven years old and already his keenly inquisitive mind was actively at work. There is a touch of romance in this young metallurgist who, on entering his. scientific career, destined to be so brilliant and so fruitful, on the very threshold of it, seems to have selected as his motto "What is Steel?" Like a knight-errant of science, he started on his quest for an answer to that question, a quest which was to last forty-seven years and which death only brought to an end. And while thus engaged how many wonderful messages we received from him, each one bringing us nearer to the goal! How illuminating, inspiring and encouraging were those messages! How well-equipped he was to wrench from nature some of the secrets she so jealously guards! How broad his learning and how clear his

Jan 5, 1924

By S. Warren Hobbs

The section of the Northwestern United States that includes the northern Rocky Mountains and adjacent areas to the west and east is one of large mineral production and important mineral potential. The metallic ore deposits vary widely in age and type and their geologic settings are similarly diverse. A brief resume of the region's physiographic characteristics and geology sets the framework for the selected ore districts that are described in following papers and makes it possible to place these ore deposits in their proper reference to space and time.

Jan 1, 1968

ROBERT PEELE, * New York, N. Y.-I should like to ask Mr. Neale how the members of the production committees at the individual mines, who came from the mine workers themselves, were chosen or appointed; also from what classes of employees they usually came? J. B. NEALE.-In the union fields, they were chosen by a local. In the non-union fields, they were chosen either by the men in mass meeting or by the company officials. The last way was very unsatisfactory because it gave the men an opportunity to say that they were going to be passed upon as to whether they were slackers or not, by men chosen by the company. When they were chosen by the locals or at mass meetings of the workers, the appointments have been very much more satisfactory. R. D. HALL, ? New York, N. Y.-The matter of inefficiency on the part of the operator is one that I think we may well take into account, because there is a very large inefficiency on the part of the coal operator; it has arisen from reasons almost beyond his control and will continue for these same reasons. It is no use arguing a moral responsibility on the part of the operator, when you make efficiency very largely a loss to the operator who puts it in force. If you ask a man working on a clay wage to work with more efficiency. he says, "Well, I may do it or I may not," it all depends how he feels, but he does not lose anything financially by not working hard. If you ask the man who is working by the ton to put out more tons, he makes a profit by putting out more tons. How is it with the operator? If he gives a man all the cars he needs and all the power he needs, if he runs after his working men and waits on them, he does not get his coal out any cheaper than before.. He gives the man a better chance and there is more efficiency, but at the same time he has increased his expenses all along the line. At the end of the year he finds that his profits have been less than if he had had less efficiency. The efficiency is really against him in many ways. Because he gets a larger tonnage, he reduces the overhead to a certain extent; but hiss tonnage may not be any greater because he may work fewer days. As Mr. Taylor remarked some tine ago, supposing he puts in a machine that is very much more effective than any he had before, he has the same scale; the miner gets out more coal, but he himself does not get any benefit out of it because he has a scale fixed, so much per ton.

Jan 4, 1919

By Eugene McAuliffe

THE last obtainable figures of the value of the coal mining investment are those contained in the U. S. Census Reports, from data gathered in 1919. The values shown therein and set forth below cover lands and equipment and do not include distribution and marketing facilities. The working capital necessary to meet pay rolls to purchase material and supplies and workmen's compensation insurance are likewise excluded.

Jan 1, 1926

By F. G. Smith

A few years ago, the writer encountered a problem that, at first, seemed to be due to peculiar conditions affecting grain growth. Large cups made from heavy metal failed in the first drawing operation in the process of making seamless tubes. The metal, as cast, appeared to be sound and strong; it rolled successfully and withstood the first cupping operation, but on the first draw it failed, with a crystalline fracture. The failure appeared in the slightly worked part of the bottom of the cup, and microscopic examination revealed exceptionally large grains. Knowing the general conditions governing recrystallization of brass, which were later published by Mathewson and Phillipsll an investigation was outlined with the idea of including various conditions under which new grains might form, and which would include the effect that a previous anneal might have upon the anneal following. These conditions were produced by annealing specimens of brass at five different temperatures, indenting them with a 10-mm. ball under four different pressures, and then reannealing at each of the five temperatures five specimens each of which had been annealed at one of the five temperatures. Preparation of Specimens The material used was cartridge brass 0.400 in. thick, having the following composition: Copper 66.60 per. cent., zinc 33.35 per cent., lead 0.02 per cent., iron 0.03 per cent. This was rolled with 35 per cent. reduction after a 700" C. anneal. Fig. 1 shows the structure of this original bar on which all subsequent anneals were made. Pieces 1 in. (2.5 cm.) wide and 3 in. long were prepared and annealed for 1/2 hr. at 450°, 550°, 650°, '750°, and 850" C. Each of these pieces are indented under the Brinell test with a 10-mm. ball at 500, 1000, 2000, and 3000 kg. pressure. Then, sets of five pieces from each of the original anneals were reannealed at 450°, 550°, 650°, 750°, and 850" C.

Jan 1, 1921

By AIME AIME

THE Engineering Education Committee of the Institute convened at the Engineering Societies Building on Feb. 18, .1929, with. E. A. Holbrook, dean of the Schools of Mines and Engineering, University of Pittsburgh, in the chair. STATISTICAL' STUDY OF STUDENTS IN MINING The first paper, a statistical study of the students enrolled in courses leading to a mining degree in 40 institutions, was presented by H. D. Keiser,, assistant editor of the Engineering and Mining Journal; who gave a brief outline of an article he was about to publish in ?that journal?. The complete article appears in the issue for March 30; 1929: To avoid repetition the results are summarized as follows: A request was sent to 42 institutions which give courses in mining' for the number of students enrolled as freshmen; sophomores; juniors, seniors and special students in mining for the years 1925-26, 1926-27, 1927-28, 1928-29. Two of these colleges replied that there were no students in mining. Students' enrolled in courses in metallurgy, geology and engineering, other than mining, were excluded from the statistics:. The statistics received were arranged in, four groups, according to the completeness of the information. One complete group of 25 institutions 'shows as follows:

Jan 1, 1929

By G. W. Healy, L. F. Sander

was investigated by reacting thin discs of calcium oxide with gas mixtures of CO2, CO, and Son. Its value was 19,300 * 300 cal independent of temperature in this range. No solid solubility of sulfur in calcium oxide was detected within the limits of the experimental method and it is estimated to be below 0.025 pct by weight. The importance of lime in desulfurization is well-established but complete information on the pure phase equilibrium: CaO + 1/2 s2 = CaS + +02 [11 is not yet available. The goal of this work was to evaluate solid solubility of CaS in CaO and to determine the free-energy change associated with Reaction [I] at temperatures of 1400" to 1650°C. The equilibrium constant for Reaction [1] can be written: It is convenient to rewrite Eq. [2] in the form: where A = {Ps /PqJ1'2 has been referred to' as the "sulfurizing power' of a gas mixture. In this work, thin discs of CaO were suspended in a vertical tube furnace and exposed to CO + CO2 + SOz gas mixtures having known values of A. The samples were then analyzed for sulfur. As expected, X-ray diffraction confirmed that CaS was the only sulfur-bearing phase formed at the relatively low oxygen pressures used. EXPERIMENTAL PROCEDURE Reagent-grade CaCO3 was pressed in a 3/8-in.-diam pill die and prefired in air to produce CaO discs weighing between 0.004 and 0.01 g. Several discs were used to provide a suitable weight for chemical analysis while maintaining a large surface area to react with gas mixtures. These were placed in a platinum mesh basket and suspended in the gas stream in the hot zone of a vertical tube furnace. Desired gas mixtures were prepared from cp grade CO and CO2 and anhydrous grade SO2. The method of soap bubble displacement was used to calibrate capillary flow meters. While this gave excellent results with CO and Con, some problems with bubble insta- bility and soap film "drag" arose with the use of SO2 at low flow rates. Hence, frequent sampling and analysis of gas mixtures was carried out to insure proper control of the ingoing SOZ. The furnace used for gas:solid equilibration was a vertical mullite tube externally wound with 60 pct Pt-40 pct Rh wire having a diameter of 0.028 in. An inner tube of $ in. ID served as the reaction chamber having Pyrex ground joints sealed to the mullite to provide gas-tight connections at top and bottom. A Pt-Pt 10 pct Rh thermocouple was inserted into a protection tube adjacent to the sample basket to measure sample temperature during a run. Constant-temperature control to 2C was observed at any desired set point within the range of this investigation. This was accomplished by a control thermocouple imbedded in the furnace windings which served to actuate an electronic controller wired for high-low operation. The sulfur analyses of the solid samples were carried out using a stoichiometric combustion technique based on the method of Fincham and Richardson. Some analyses were done using a modified evolution method3 but these were used primarily to check the results of the combustion method. The results were in good agreement but the combustion technique of-ferred an advantage in economy of time and material. CALCULATION OF GAS EQUILIBRIA Heating a given mixture of CO + CO + SO2 to high temperatures gives rise to a large number of product species. The details of calculating the partial pressures of these products of interaction and dissociation can be found in several references4,5 and need not be repeated here. The thermodynamic data selected for the major species in the gas mixtures are shown in Table I. Equilibrium constants from these reactions were combined with oxygen, carbon, and sulfur balances and a computer program written to facilitate the calculations. Some early difficulties in reproducing experimental results were finally traced to the effect of atmospheric pressure changes. No reference to consideration of this question had been found in the

Jan 1, 1969

By N. A. Gjostein

The real and apparent dependence of the surface self-diffusion coefficient, Ds, of gold on crystallo-graphic orientation has been investigated by isolated scratch smoothing and grain boundary grooving experiments. No systematic variation of Ds with orientation was found along the [100] zone. In view of the experimental scatter in these results, however, only aniso-tropy ratios, p, greater than -1.3 would be detectable. Anomalously low values of Ds were found on the [0ll] and [110] zones when the diffusion direction lies along (the scratch or grain boundary groove is perpendicular to) these zones. By comparing these results with a previous y plot study of gold, it is hypothesized that this is not an intrinsic diffusivity effect, but rather it results from a decreased driving force for mass transfer at orientations where the y-plot curvature is negative and appreciable in magnitude relative to y. The characteristics of this type of anisotropy do not appear sEVERAL investigations1-7 have dealt with the anisotropy of the surface self-diffusion coefficient, Ds, of metals as measured by the decay of single or multiple to be in agreement with the hypothesis of fast diffusion along ledges in the surface structure. In certain cases the Fourier method of determining Ds, described in Paper I of this series9 was compared with the second moment analysis in order to determine whether or not the method of analysis affects the anisotropy ratio. While the type of analysis does influence the magnitude of the anisotropy ratio, this effect is not associated with the shape of the profile, but rather is connected with the iterative volume diffusion correction used in conjunction with the second moment analysis. It is further demonstrated that the volume diffusion correction can be too large by either method when the y-plot curvature effect is large. Certain orientations exhibit an unusual temperature dependence of Ds ; this is discussed in terms of the y-plot curvature effect and/or the influence of impurities on Ds . scratches in the surface. Depending on the system investigated, both large1"3'6'7 and small4'5 anisotropies in Ds have been found. Although adsorbed impurities undoubtedly play an important role in determining the magnitude of the anisotropy,8 there are other factors that can give rise to an apparent anisotropy in Ds, thus obscuring the true nature of an intrinsic anisotropy in

Jan 1, 1968

By Charles Bohdanowicz

As in preceding years, the most intensive drilling activity during 1934 took place in the old fields of the western part of the Polish Carpathian petroleum province (district of Jaslo). The number of wells completed to the end of 1934, expressed in percentages, is as follows: Jaslo district, 57 per cent; oil fields outside Boryslaw-Tustanowice-Mraznica, 27; Stanislawow district 8 and Boryslaw fields only 7 per cent. The number of meters drilled (Table 2), expressed in percentages, for the same fields are as follows: Jaslo district, 51 per cent; oil fields outside Boryslaw-Tustanowice-Mraznica, 26; Stanislawow district, 12, and Boryslaw oil fields, 11 per cent. This comparison shows that most of the new

Jan 1, 1935

By George Espey, George Sachs, G. B. Kasik

IT has been reported frequently that the hardness and strength vary over the cross section of cold-worked, particularly cold-drawn, material. Brass rod and wire usually have been found to possess a maximum strength and hardness near the surface.1,2 According to Sachs,' the center fiber has about the same strength as a wire stretched by the same amount in a tensile-test machine, the strength increasing toward the surface (Fig. I). These differences are particularly large for wire given a small reduction on drawing through a die with a wide opening. However, with increasing reduction and hardness, a tendency to form a thin soft surface skin becomes apparent. On the contrary, copper wire has usually been found to possess a soft surface skin3-5 and it has been reported by Harris3 that during the cold-drawing of hot-rolled wire the surface layer becomes increasingly softer than the core, while the layer of maximum strength moves toward the core, it being found near the surface at first. The increase of strength and hardness from the core to the skin is readily explained by the observation that, in addition to the stretching, the layers of a rod or wire are sheared more the closer they are to the surface.1,6-8 However, the presence of a soft surface layer can be attributed only to an annealing effect. The source of such a softening might be the extremely high temperature that originates from the friction between

Jan 1, 1942

By G. B. Kasik, George Sachs, George Espey

IT has been reported frequently that the hardness and strength vary over the cross section of cold-worked, particularly cold-drawn, material. Brass rod and wire usually have been found to possess a maximum strength and hardness near the surface.1,2 According to Sachs,' the center fiber has about the same strength as a wire stretched by the same amount in a tensile-test machine, the strength increasing toward the surface (Fig. I). These differences are particularly large for wire given a small reduction on drawing through a die with a wide opening. However, with increasing reduction and hardness, a tendency to form a thin soft surface skin becomes apparent. On the contrary, copper wire has usually been found to possess a soft surface skin3-5 and it has been reported by Harris3 that during the cold-drawing of hot-rolled wire the surface layer becomes increasingly softer than the core, while the layer of maximum strength moves toward the core, it being found near the surface at first. The increase of strength and hardness from the core to the skin is readily explained by the observation that, in addition to the stretching, the layers of a rod or wire are sheared more the closer they are to the surface.1,6-8 However, the presence of a soft surface layer can be attributed only to an annealing effect. The source of such a softening might be the extremely high temperature that originates from the friction between

Jan 1, 1942

By W. A. Backofen, D. H. Avery, W. F. Hosford

Sheets of the magnesium alloys AZ31B, HK31A, and ZE10A in several different tempers were tested in tension and determinations were made of the ratio of width-to-thickness strain. A marked increase in the ratio with tensile straining and a dependence upon alloy and test direction are rationalized in terms of a balance between the amounts of basal and prism-plane slip. All such variations are related, in turn, to the prevailing crystallographic texture. Fracture appearance is explained on the basis of anisotropy in plastic flow, and implications for developing texture -hardening effects in these alloys are discussed. ThE crystallographic texture or preferred orientation of a given material is determined by details of processing history. Such texture is known to influence many aspects of material behavior, in particular both the yielding and strain-hardening characteristics which are of special interest in the present work. Traditionally, the resulting plastic anisotropy has not been regarded as especially desirable. Earing in drawn sheet is perhaps the most common example of an unwanted effect of texture. However, it has also been recognized that suitable textures may be usefully employed to improve drawability,1,2 as a specific example, and generally to control yielding resistance under combined-stress loading.374 Texture would seem to be a detail of structure not yet exploited to nearly the fullest extent. A convenient basis for characterizing anisotropy in plastic behavior is the ratio of width-to-thickness strains obtained in a tension test;5&apos;6 the parameter is frequently labeled "R" and its value is revealing with respect to the nature of the prevailing texture. R gives a useful measure of a material&apos;s "thinning resistance". For an isotropic material, R = 1. With R > 1 the increased through-thickness strength in a sheet means greater resistance to yielding under biaxial tension, or "texture hardening";3&apos;4 if R < 1 the result may be a "texture softening" under the same loading conditions.4 Most R data relate to steel sheets for deep-drawing applications. Values for steel and other materials of cubic structures are not often much greater than 1 and nearly constant with strain in testing.1,2,7,8 To explore the implications of plastic anisotropy further, it was felt that experiments with much more strongly textured materials would be useful, and this led to the choice of magnesium alloys. The "ideal" sheet texture for magnesium contains the (0001) plane in the rolling plane, which ought to lead to R values approaching infinity. However, departures from the ideal texture, the possibility of slip in non-close-packed directions, and deformation by twinning would all be expected to introduce some range of R. Accordingly, studies on these materials were undertaken. EXPERIMENTAL Alloys in sheet form, Table I, were selected to obtain a variation in crystallographic texture, in the expectation that this would be reflected in differences in plastic anisotropy. Pole figures constructed by the Schulz surface-reflection technique9 were provided with the experimental materials by the Dow Metal Products Co. Profiles of pole density along great circles through the rolling (0 deg) and transverse (90 deg) directions were prepared from the pole figures and are collected in Figs. 1 and 2; considerable departure from the "ideal" (0001) alignment in the rolling plane is evident, with the largest angular spread in both directions being found in the ZEl0 alloy. Results of tensile tests on full-thickness specimens of 6-in. gage length by 1/2-in. width are given in Fig. 3 as engineering stress-strain curves* in rolling and transverse directions. All tests but one were made at a constant drive rate of 0.02 in. per min, and the final values of percent elongation at fracture, over the initial 6-in. gage length, are noted at the ends of the curves; one test on ZE10A-

Jan 1, 1965

By Victor Rakowsky

A CLEAR understanding of the factors that deter-mine the consumption of zinc metal is essential to a proper survey of the future of the industry and the relation of the several producing districts. With a view of explaining a sound basis for the consider-ation of some of the problems facing the zinc-mining industry of the Oklahoma-Kansas and Missouri district some of these factors are here set out. The zinc industry of the United States furnishes metal for three major uses, viz.: (1) zinking iron and steel (galvanizing); (2) brass making; (3) sheet rolling. Other important uses are for lead desilverization, the manufacture of castings, including die castings, and the manufacture of zinc oxide by the French process, which consists in burning spelter. The use of zinc for galvanizing comprises the coating of sheets, tubes, wire and shaped products, the latter ranging from chains to buckets. The brass-making industry may be sub-divided into manufacture of red brass, yellow brass and white brass, the percentage of zinc in these products being roughly 30, 40 and 80 respectively. The use of white brass is relatively a new thing and it may attain considerable proportions as a substitute for yellow brass. Ingalls estimated the percentage of total metal consumed for the above purposes in pre-war times as follows: HIGH PRODUCTION RECORD, SHORT TONS USES PERCENTAGE OF METAL Galvanizing 60-65 210,000 in 1912 Brass making 17-20 175,000 in 1916 Rolled sheets 10-12 57,000 in 1917 Other uses 5- 7

Jan 3, 1923