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By J. L. Swedlow, M. L. Williams

Two standard techniques for assessing fracture initiatlon in sheet specimens involve measurements of 1) the applied load of fracture which, via linear fuacture mechanics, is used to find the fracture tough/less SC (or SIC), and 2) the velative displacement of fracture of the opposite free faces of the crack (COD). In the past, the quantitative association between these two parameters has not been determined in detail, owing to the mathematical difficulties of computing. the stress and strain fields in the combined elasto-plastic flow near the crack. Using a numerical technique Irecently developed and applied to a 7075- TO' aluminum plane stress specimern, the two parameters noted have been determined and associated quantitatirely. CONSIDERABLE effort has been expended in selecting a rigorous yet practical manner for predicting fracture. The usual point of departure is the modified Griffith criterion in which the mechanism of energy dissipation is reflected in Sc (or SIC), the parameter of "fracture toughness". Sc. differs from the surface energy used by Griffith in perfectly brittle fracture in that it includes the effect of plastic flow in the vicinity of the crack tip. Because plastic flow alters the stresses and displacements predicted from the usual linear theory of fracture mechanics, and because analysis of the nonlinear stress-strain field has presented great obstacles: only estimates of several pertinent quantities have heretofore been available. Nevertheless, two parameters have often been measured experimentally althougll usually just at the point of fracture. These are the energy release rate, or fracture toughness 9, (or I,), and the crack-opening displacement (COD). Such observations have been used in connection with frarture criteria and have been most helpful in design, although their application requires care with respect to changes in geometrical configuration from that upon which the criteria were based 1,2 Recently, however, a reasonably accurate and comprehensive method for analyzing the elasto-plastic flow has been devised and applied to plane stress specimens having arbitrary octahedral stress-strain curves.3 It thus becomes feasible to compute, albeit numerically, both the fracture toughness and crack opening as functions of the applied tensile loading on a typical specimen geometry. As a result, it is now possible to associate these two parameters quantitatively, and thereby to associate data obtained by one method with data pertaining to the other. ELASTIC ANALYSIS For the case of linear elasticity, it is relatively easy to deduce the connection between various measures of crack deformation. Using, for example, the singularity analysis, it is found that the leading term of the Airy stress function x f°r symmetrically applied loadings on an isotropic medium is

Jan 1, 1968

By Henry A. Stiff, J. P. Hammond, A. B. Westerman, H. C. 195-000-000-014 Cross, and Lawrence E. Davis

The phases in Cr-Fe-Mo alloys have been investigated with homo-genization, aging temperature, composition range, and alloy addition as variables. Metallography, three X-ray methods, and hardness were used as methods of study. The behavior of s, M23,C8, and Z phase are reported for cornpasition range 60 pct Cr-15 to 25 pct Fe-15 to 25 pct Mo-<0.005 to 0.36 pct C with aging at 1400º to 2000°F. With 2 pct Ti, Tic and TiC-TiC are formed; with nitrogen Cr2N. THE recently developed class of chromium-base heat-resistant alloys shows appreciably higher strength than commercially used high temperature alloys. However, further developmental work is required to impart needed shock resistance and some degree of room-temperature ductility to these alloys. Extensive exploratory work on chromium-base alloys was begun in a program initiated by the War Metallurgy Committee of the National Defense Research Council at the Climax Molybdenum Co. in the early part of 1942.&apos; Alloys were sought for gas-turbine blades for use at 1600°F. A minimum of 5 pct elongation in the stress-rupture test was a requirement. From the Climax work, ternary alloys of chromium, iron, and molybdenum appeared to show the greatest promise as materials for gas-turbine blades. The composition line in the ternary diagram joining the 60 pct Cr-15 pct Fe-25 pct Mo and 60 pct Cr-25 pct Fe-15 pct Mo alloys was indicated as representing the most useful combination of strength and ductility.&apos; Strength increased while ductility decreased as molybdenum was raised in this composition range.&apos; The 60 pct Cr-15 pct Fe-25 pct Mo type alloy was thought to have the most suitable properties for gas-turbine blades.&apos; Concurrent with the study reported here, other investigations were being made on Cr-Fe-Mo alloys. The liquidus temperatures on a series of low carbon, ternary alloys were being determined, and isothermal sections drawn at 2370°, 2010°, and 1650°F (1300°, 1100°, and 900°C).2 Also, various methods of preparation and some mechanical and physical properties of chromium-base alloys, particularly the 60 pct Cr-15 pct Fe-25 pct Mo type, were being investigated., At the inception of the present program, only a limited study had been made of etchants for developing the microstructures of chromium-base alloys; X-ray analysis of the microconstituents had not been made. A review of the literature revealed that no phase-diagram work had been reported on the Cr-Fe-Mo system. Scope of Work The work on chromium-base alloys includes the following: 1—The development of etching methods for differentiating between the microconstituents; 2—The identification of microconstituents by X-ray diffraction methods; and 3—A comprehensive metallographic and hardness study after various heat treatments. The phases were studied by three standard X-ray techniques: 1—The block-sample focusing-camera method; 2—The powder-diffraction method on elec-trolytically separated residues; and 3—The powder-diffraction method on cold-worked aggregate samples. The results by the first two methods were correlated with the metallographic data. The third method was used largely to study conditions approaching equilibrium, since cold working prior to heat treating accelerated precipitation. Seven types of alloys were investigated: 50 pct Cr-50 pct Fe, 40 pct Cr-40 pct Fe-20 pct Mo, 55 pct

Jan 1, 1953

By G. C. Gould

The nature of freckle segregation is determined by chemical analyses, microradiograplzy, and electron microprobe. In addition, the influence of chemistry variation on freckle formation is studied in laboratory experiments. It is demonstrated that controlled laboratory solidification can produce freckle segregation. "FRECKLE" segregation is a discontinuous, rod-like segregation observed in vacuum consumable -electrode ingots. Figs. 1 and 2 show this segregation as pencil-like, dark etching areas of segregation found in longitudinally and transversely sectioned consumable-electrode ingots. In most cases the segregation is perpendicular with respect to gravity and parallel to the longitudinal axis of the ingot. The segregation is most often encountered at or around midradius in large vacuum consumable-electrode ingots. The austenitic alloys, A-286* and 718, † have shown particular susceptibility to this mode of segregation. The origin of these rodlike pockets of segregation is not well-understood. It has been suggested that the segregation is a result of a portion of the electrode dropping off and passing through the arc un-melted. On the other hand, smeltzer1 has demonstrated the freckle segregation in A-286 to be comprised of low-melting constituents relative to the matrix melting point. The discontinuous nature of the segregation is the most perplexing facet of the freckle-segregation problem. It was to gain some insight into this part of the problem that this work was undertaken. I) PROCEDURE At the outset of the work identification of the phases present and the elements concentrated in the freckle areas was undertaken. The electron micro-probe was used to determine general enrichment as well as -specific phase chemistry. Microradiography using cobalt and chromium radiation was also used on the freckle areas again to determine the elements involved in the segregation. X-ray diffraction patterns were made from portions of these same foil specimens. Optical microscopy and Knoop hardness measurements were also used

Jan 1, 1965

By George W. Doffing

Numerous contradictory statements have been made in the past regarding the importance of the seasonal influence of demand for motor fuel on prices of oil securities. It has often been said that the time to buy oil securities is in the spring, or just prior to the heavy consuming season for gasoline. The fallacy of this argument is brought out in the following paragraphs. Seasonality of Oil-security Prices The indexes used in this paper as indicators of prices of oil securities and general industrials are those compiled by Standard Statistics Co. The oil producing and refining stock index includes 14 representative petroleum companies, while the all-industrials index is made up of 347 issues. All figures are stated as relatives, with 1926 = 100. The primary basis of the index, and one that gives a good weighting of the relative importance of the company within the industry, is the total market value of the stock issue outstanding; i.e., the market price times the number of shares outstanding. Adjustments are made for the addition or elimination of issues from the group index, for stock dividends, split-ups, stock rights, et cetera. At the present time the oil producing and refining index includes the following companies: Atlantic Refining Co., Consolidated Oil Corporation, Continental Oil Co., Gulf Oil Corporation, Humble Oil & Refining Co., Ohio Oil Co., Royal Dutch Co., Shell Union Oil Corporation, Socony-Vacuum Oil Co., Standard Oil Company of California, Standard Oil Co. (Indiana), Standard Oil Co. (New Jersey), Texas Corporation, Union Oil Company of California. In calculating the seasonal for oil-security prices several periods have been selected as indicat,ive of major changes in the industry, as follows: 1. 1918 through 1936. This gives an over-all picture of the industry during the motor-vehicle, motor-fuel era. 2. 1927 through 1936. This period includes the control stages, both voluntary and coercive. 3. 1927 to September, 1933. This is the pre-code period of control.

Jan 1, 1937

E. E. BACH, Ellsworth, Pa.-A personal interview with a man is one factor in reducing labor turnover; his working conditions is another, while the conditions under which lie brings up his family is still another; all have much to do with the reduction of labor turnover. A man well placed, happy in his work and happy in his home, will stay put and incidentally decrease the labor turnover in any industry. C. R. HOOK, Middletown, Ohio.-I am so deeply and sincerely interested in the employment problem, that it is very difficult for me, once I get started, to know when to, stop. In the first place, I want you to understand that I realize that what may be a possible accomplishment in the plant with which I happen to be connected, may not be possible of accomplishment in the same way in your plant. Our problems might be quite different; our location might be quite different, and therefore our employment problem would be very much affected by the community conditions. Two of our plants happen to be located in a town of about

Jan 4, 1918

By John L. Boardman

BECAUSE of the attention that has re¬cently been given to the health and safety of miners by various organizations such as the A.I.M.E., The American Congress, Mining Section, National Safety Council, as well as the Bureau of Mines and various state mining departments, your committee on health and safety deemed it best to call attention this year to the mine-accident cause that is by far the most important; namely, injuries due to falls of ground, rock, roof and coal. Each of several members of the committee contributed a brief outline of the importance of this accident cause in his district. While these papers were brief, it would require too much time and space to give them in full, therefore we present an outline of each and summation of all. REPORT OF M. D. COOPER, HILLMAN COAL AND COKE CO. M. D. Cooper, Division superintendent, Hillman Coal and Coke Co., Pittsburgh, Pa., contributed the following: During the period from 1930 to 1939, accidents from falls of roof in bituminous mines average 54.3 per cent of all accidents. In mechanized mining, there is a tendency toward reduction in this class of accidents because the operator of the machine is usually at a distance of 10 to 20 ft. from the face, whereas. in hand loading the miner is close to the face during most of the shift. No doubt the use of aluminum and light steel beams supported at regular intervals by jacks, a common practice in mechanical mining, has contributed to the favorable record so far developed. REPORT OF M. H. FIES, DE BARDELEBEN COAL CORPORATION Milton H. Fies, Vice-President, DeBardeleben Coal Corporation, Birmingham, Ala., says: With reference to the types of mining, it is suggested that a clear understanding be had as to the character and thickness of the directly overlying strata, with especial consideration to the strength and in some cases an analysis of it. In coal mining, generally speaking, overlying strata higher in silica than others is stronger. In changing from narrow to wide places, the procedure should be experimental, both as to the width and depth of places and as to the nature of the necessary timbering. Since most of the accidents in coal mining particularly are due to falls of roof and coal, this phase of mining should be attacked with vigor. There is no substitute for discipline and, in this connection, under present conditions it is important that cooperation by the labor organizations be sought and that a spirit of fairness prevail. Frequent and thorough inspection of all active working places should be made.

Jan 1, 1941

By Raymond Ward

IN the past few years several papers have appeared dealing with different aspects of the oxidation of dilute alloys, especially with respect to the formation of internal oxides or subscales. Subscale has been defined1 as that layer or zone of oxide particles precipitated in a matrix of metallic metal in which the oxide particles are dispersed uniformly and occur by diffusion of the oxygen inward from the metal surface. Alloys composed of a solvent metal more noble than the alloying elements are subject to subscaling or internal oxidation. In these alloys the solute must be present in such quantities that if the alloy is exposed to an oxidizing atmosphere at elevated temperatures, the rate of diffusion of the oxygen into the metal will be greater than the rate of diffusion of the solute outward. There is a composition range of the iron-silicon system that falls into this classification. Knowledge of the nature and rates of oxidation of iron-silicon alloys is of great commercial importance, but very little information of this nature is available. Darken2 recently has made calculations to show the limits of concentration of silicon for which subscales are produced in iron-silicon alloys; however, the main thesis of his paper was to analyze and to explain the already existing data. The purpose of this paper is to present the effect of com position, temperature, time, and atmosphere on the type of scale-metal layer obtained and to give some qualitative indication of the effect of these variables on the rates of oxidation. Since this paper is a study of silicon steels that are available commercially, extremely low-silicon and high-silicon alloys are not included. EXPERIMENTAL PROCEDURE The alloys used in the experiment were taken from heats of silicon steel that ranged in analysis from 0.70 to 5.8 per cent silicon. This composition range takes in most of the commercial silicon steels. In Table I are listed the compositions of alloys used. Other than iron and silicon, the alloys normally contained approximately the following impurities: carbon, 0.03 per cent; manganese, 0.07; phosphorus, 0.008; sulphur, 0.02; copper, 0.07; tin, 0.01, and from nil to a trace of chromium, nickel and copper. All of the alloys used were melted in open-hearth furnaces, except where otherwise noted, and were hot-rolled to 0.100-in. plate. Samples approximately 1/2 in. square were then cut from these materials. So that the surface conditions of the samples used for oxidation would be standardized, each sample was ground through 000 emery paper immediately before oxidation. Two different techniques were employed in carrying out the oxidizing treatments. One consisted simply of heating the samples with free access to air. In this treatment the samples were set on edge on a refrac-

Jan 1, 1945

By Richard V. Hughes, Rudolf J. Pfister

The necessity for getting more water into sands of low permeability in any secondary-recovery water-flood operation in order to recover all the available oil always has been a major problem. In the early days of water-flooding the addition of soda ash and caustic soda to fresh input waters was recommended and tried without success in the Bradford field. The most frequent difficulty was sand plugging. The use of natural and artificial brines often has been suggested for water-flooding, in the belief that laboratory observations of decreasing fresh-water throughput rates in measuring water permeabilities of consolidated sand cores might be partially explained by swelling of clays. A review of available literature bearing on the subject and related laboratory experiments are presented herein, offering an explanation for failure in use of soda ash and caustic soda waters and supporting the recent concept that every water used for input purposes in the secondary recovery of oil should possess such physical and chemical characteristics as to keep the clay content of the producing sands in a permanently flocculated condition. Produced brines meet this requirement. Their use is recommended as a means of increasing intake rates of tight sands and oil recoveries, as a solution to brine-disposal problems, and as a means of conserving a natural resource. Introduction There is a general belief among those engaged in the secondary recovery of oil by water-flooding that one of the most important requirements for the success of any such project is an adequate supply of good, fresh water. Fresh waters have the advantages of being more easily stabilized than salt waters and of being usable about the lease for all purposes. The use of brines for water-flooding never has been given much consideration in the Pennsylvania Grade area. The use of brines in Mid-Continent operations has been considered largely as a substitute for fresh waters, which were economically unobtainable for many operations. Estimated recoveries for some water-drive fields indicate that less of the original oil in place will be left upon abandonment than with the above-average practices used in Pennsylvania Grade water-flood operations. Lower residual oil saturations than 25 pct of the pore space following the water-flooding of Third Bradford sand cores in the laboratory are unusual. In comparison, water-flushed sands surrounding any virgin oil pool are found to be practically devoid of oil. Such lower natural residual oil saturations may be the result of a time factor much longer than economic under artificial water-flood operations, but neither the producer of primary oil nor the producer of oil by secondary recovery can obtain maximum recoveries unless full advantage is taken of all natural forces and

Jan 1, 1947

By L. D. Clark

Jan 1, 1964

By H. G. Doll

&apos;This paper discusses a method and apparatus for determining the dip of formations traversed by a drill hole, by means of electrical measurements in the hole. The process consists in recording the Spontaneous Potentials present along three oriented generatrices in the hole. By comparison of the three curves thus obtained, after application of a correction factor to compensate for any deviations of the hole, the dip angle and the dip direction are determined. Excellent accuracy is obtained for dip angles over 10°. Because the method is simp1e and the apparatus rugged, the measurements are rapid and reliable; consequently, they can be made at all the levels that are of interest at any time after the well has been drilled. Mechanical cores are not needed to evaluate the dips. A convenient, time-saving procedure is to perform the dipmeter survey at the time the electrical log is taken, using for both operations the same cable and truck. Actual examples of results obtained in wells of the Gulf Coast area are given. Introduction The problem of determining the angle and direction of the dip of the strata traversed by a drill hole has practical interest, and sometimes vital importance, which need not be emphasized to the oil industry. The need for that type of information has existed ever since wells have been drilled. Certainly it has not subsided, in spite of the numerous inventions and improvements made in other fields of the art of drill-hole exploration. The few examples given in this paper are but illustrative of this fact. In the past, methods have been devised, and used, to solve this problem, but generally they have met with limited success, possibly because they failed more or less to answer the requirements of a modern age for fast yet accurate measurements. If accurate, the results were obtained at the cost of very tedious and lengthy operations. The new S. P.* dipmeter service offered to the oil industry is the result of exhaustive and in this particular field. In 1032 a dipmeter and electromagnetic teleclinom-eter service was made available. The apparatus employed then was of a rather delicate and costly construction, and the measurements had to be made with precautions sometimes difficult to secure on the rig. Although the information given by the electromagnetic dipmeter was limited to the direction of the dip, very interesting results were obtained in California, Trinidad, Venezuela, Rumania and, most notably, in the Netherlands East Indies.+ Apparatus The S. P. dipmeter surveys present none of the drawbacks mentioned above. The apparatus is rugged and free from constructional complications, therefore well adapted to field use. This, combined with the new, basically simple approach to the problem, explains the rapidity of execution of the measurements. The results are remarkably accurate and they are complete, giving the

Jan 1, 1946

By P. P. Scott, George C. Howard

A field remedial procedure utilizing a kerosene-cement slurry as a water plug-off agent in fractured formations was evaluated both in the laboratory and in the field. This procedure has proved to be capable of effectively shutting off water without causing permanent impairment of the oil production. Success was attributed to the fact that an immobile cement slurry, when placed in a water-producing strata, will set and form an impermeable barrier; whereas when placed in an oil-producing section the cement will retain a relatively high permeability and may be removed by acidizing. INTRODUCTION One of the most perplexing problems facing the oil industry is the selective exclusion of water production from oil or gas-producing wells. This problem has been studied by many investigators in an attempt to develop a material that is not only capable of reducing water production but is also capable of being selective in that it will not impair oil production in either fractured or intergranular type reservoirs. A study of these two types of formations indicated that two distinct types of materials for controlling water production might be required — a completely liquid plugging agent for intergranular formations and a semi-liquid or slurry type plugging agent for fractured formations. This paper is limited to the control of water production from fractured formations. A common source of water in the vicinity of oil bearing rock reservoirs is water which previously has entered and, because of its higher density, generally lies near the bottom of the formation. When the deepest point of penetration of a well into such an oil and water-bearing formation is above the level of the water, and the dynamical gradients due to the flow of oil overbalance the difference in densities between oil and water, water production becomes a problem. Then the water level rises in the shape of a cone and is produced from the lower depths. Other investigators1,2,3,4 have developed theories which define the pressure gradients and contours of this cone in a homogeneous formation and have shown that the placement of a plug in the bottom of a well is only slightly effective in temporarily reducing the flow of water. Assuming that the manner of flow of bottom water from fractured formations to a well is generally similar to the flow in homogeneous formations, then it would be expected that some form of coning, perhaps of less symmetry, would also occur. Then, because of the similarity of the manner of flow of water, placement of a vertical plug in a fractured formation would also probably be ineffectual for controlling water production. However, as has been shown by electric model flow study,&apos; the placing of a plug in a well and an impermeable horizontal streak in the formation might prove to be a means for materially reducing or even eliminating water production in a fractured formation. An indication of the difference in effectiveness between horizontal and vertical plugs based on theory developed from study of the flow of water and oil in rock reservoirs is depicted in Fig. 1. These curves show the expected

Jan 1, 1955

By Abdel Kadir Attia, Haydn H. Murray, Adel Abdel Azin, Sabah N. Boulis

An extensive reconnaissance survey of bentonitic clays in Egypt was carried out from 1982 to 1984. X-ray diffraction, differential thermal analysis, electron microscopy, and physical property evaluations were used to identify the mineralogy and assess their industrial potential. Samples were collected from a number of localities, namely Qasr El-Sagha (Fayum), Cairo-Alexandria Desert Road (Western Desert), and Qattamia area (Eastern Desert). This paper reviews the geological occurrence, the mineralogical and chemical characteristics, and the potential utilization of these deposits.

Jan 1, 1985

By Charles H. White

Methods in colorimetry are based on the assumption that the intensity of the&apos; color of a definite volume .of solution is directly proportional to the quantity of the color-producing substance present. In the preparation and examination of colored solutions there are three ways in which the depth of color may be varied. These variables are : (1) the quantity of&apos; the coloring matter; (2) the quantity of the solvent, or the dilution ; and (3) the thickness or depth of that portion of the solution examined. With these three variables as a basis, three general methods in colorimetry have been devised, all of which have been used in the determination of carbon in steel. In the first method, the quantity of the solution is kept the same for both the unknown steel and the standard, and the sections compared are of equal thickness, while the quantity of the standard is varied until the color obtained is of the same intensity as that produced by a definite quantity of the unknown steel. In laboratories where this method is used there is prepared and kept for permanent use a series of solutions with varying amounts of the standard, representing the percentages of carbon from the lowest to the highest demanded in that laboratory. These standard solutions are kept in bottles or test-tubes of equal diameter, and are arranged in series from the faintest to the most intense color, so that it is a simple matter to find the place of the unknown steel in the series, when the solution is of a definite volume and is contained in a tube of the same diameter as the standard tubes. In the second method, equal quantities of the standard and of the unknown steel are dissolved, the standard is diluted to a definite volume, and the solution of the unknown steel is di-

Jan 1, 1907

By A. P. Young, L. I. Marsh

HE relationship between microstructure and *- fracture is of interest in many metals and alloys. This relationship is sometimes established by examining the fracture surfaces and the flat surfaces near the fracture path in tensile samples. However, it is often difficult to tell from examining the fractured sample whether the fracture is intergranular, intra-granular, or a mixture of both. Also, it is often of interest to follow the progress of slip, twinning, or crack formation along the fracture path before fracture occurs. The ambiguity concerning the type of fracture generally can be resolved if the area along the path of ultimate fracture can be photographed at inter-

Jan 1, 1959

By D. F. Kaufman, E. D. Levine, L. R. Aronin

ThE primary slip plane in hcp metal crystals can usually be inferred from the c/a ratio. Basal slip is the primary system at room temperature for zinc, cadmium, magnesium, cobalt, and rhenium, all of which have a c/a ratio greater than 1.60. Zirconium and titanium, on the other hand, each with a c/a ratio of 1.59, deform primarily by (1010) [ll20] prismatic slip. The increasing tendency toward prismatic slip in these materials is generally thought to be associated with the increase in atomic density on (10i0) as c/a is reduced. Beryllium, with a c/a ratio of 1.57, would, according to the above scheme, be expected to exhibit prismatic slip. However, in beryllium of commercial purity, the primary deformation mode at room temperature is basal slip.&apos; The ratio of critical shear stress for prismatic to that for basal slip at room temperature is approximately 5:l. The critical shear stress for prismatic slip decreases quite rapidly with increasing temperature, however, and at 500°C the ratio is approximately unity. The apparently anomalous behavior of beryllium has led to speculation that prismatic slip in this material may be restricted by an anisotropic effect of impurities,&apos; and that, if beryllium could be purified to a sufficient extent, prismatic slip might predominate at room temperature. In such a case, the conditions under which basal cleavage can occur would be suppressed, and enhanced low-temperature ductility might result. With the advent of the floating-zone method for purification of beryllium,3 it has become possible to determine experimentally the effects of purification on basal and prismatic slip. Tensile tests were performed at room temperature on single crystals oriented favorably either for basal or prismatic slip. The crystals had been purified to various extents by zone-refining, employing procedures that have been described elsewhere.4 Relative purities of the crystals were estimated by measuring the ratio of electrical resistance at 4.2"K to that at 298°K. Typical values ranged from 0.40 for commercial-purity material to 7.7 X 10"4 for crystals prepared from vacuum-distilled beryllium and subjected to six zone-refining passes. The purity dependence of the critical shear stresses for basal and prismatic slip is shown in Fig. 1. In the purity range studied, the critical shear stress for basal slip is decreased from 1.4 to 0.14 kg per sq mm. The critical shear stress for prismatic slip is decreased from 6.7 to 5.3 kg per sq mm. The decreases in critical shear stress for each deformation mode, therefore, are approximately equivalent. No purification anisotropy is observed. Because of the absolute magnitudes of the critical stresses, the ratio of the critical shear stress for prismatic slip to that for basal slip actually increases from 5:l to 38:l at the highest purity level studied. It is evident, therefore, that basal slip is the primary deformation mode in high-purity beryllium. This fact must be accounted for in any rationalization of the deformation behavior of hcp metals. This work was performed at Nuclear Metals, Inc., under the sponsorship of the U.S. Atomic Energy Commission.

Jan 1, 1964

By W. R. Crane

DRAINAGE in these mines has been discussed in papers, on mining practice,1 but the fact that water, varying from 0.16 to 3.46 and averaging 1.43 times the amount of ore mined, has to be pumped from the mines daily, indicates the importance of the problem and the advisability of making a thorough investigation of the source of mine water, its mode of entry into the mines, its effect upon mining conditions; and consideration of means of improving the conditions. While conditions are not serious, yet there is danger that they may become worse if present mining practice is continued, owing to the presence of formations, known to carry large quantities of water, that overlie the ore bed worked. Much detailed information has been collected regarding: rainfall, and run-off in streams draining the district; the effect of different kinds of formations, porous and non-porous; the inclination of the surface; the condition of the surface above the mines, i. e., whether or not disturbed by ground movement; the occurrence of the ore and character of associated formations, particularly with respect to presence of jointing or slip planes, faults, etc.; failure of top rock in the old stopes; and the conditions under which water effects entrance into the mines, i. e., whether as a natural or forced flow. The study furnished fundamental data on the source of waters now entering the mines and that which may later enter due to collapse of top formations in. abandoned workings. The presence of jointing, or slip planes, has a pronounced influence upon the whole drainage problem. These present lines of least resistance to the water and, by weakening the top formations, cause fracturing of the overlying rock, allowing both surface and deep-seated waters to enter the mines.

Jan 1, 1927

By J. C. Uy, T. E. Davidson, A. P. Lee

The effects of hydrostatic pressures to 26 kbars on the micro structure of poly crystalline Cd, Zn, Bi, Sn, Zr, Mg, Cu, and Fe were examined. Pressure-induced microscopic plastic flow in the form of boundary migration, slip, multiple slip, or twinning has been observed either singly or in combination in cadmium, zinc, bismuth, and tin. No deformation was observed in zirconium, magnesium, copper, and iron. The occurrence of such deformation, in terms of its intensity and initiation pressure, relates directly to the degree of anisotropy in the linear compressibility. Pressure cycling does not significantly affect the residual tensile properties of a zinc alloy which exhibits pressure-induced deformation similar to that of Pure zinc. CLASSICAL elastic theory predicts that a superim-posed hydrostatic pressure will not induce shear stresses in an ideal material. Thus, in the case of homogeneous and isotropic materials plastic flow will not occur as a result of pressure exposure, regardless of the magnitude of the pressure, unless some form of phase transformation or permanent density change takes place. However, real materials, such as metals, often vary considerably from the condition of homogeneity and isotropy. For this reason, Vu and johannin&apos; examined and observed hydrostatic pressure-induced microscopic deformation in polycrystalline cadmium and, zinc, but not in aluminum, to pressures of 9 kbars and indicated that its occurrence is related to anisotropy in the linear compressibility. In addition, Davidson and omaan&apos; have reported pressure-induced deformation in polycrystalline bismuth below the 1-11 transformation pressure. It becomes apparent then that under certain conditions hydrostatic pressure can induce localized internal shear stresses in some metals of sufficient magnitude to cause plastic flow. In this work, eight pure single-phase metals of different lattice structures and degrees of elastic anisotropy were examined after pressure exposures of up to 26 kbars in order to establish the conditions under which such deformation occurs and the type of deformation as a function of pressure. The effects of pressure cycling on the mechanical proper-

Jan 1, 1965

By K. V. S. Sastry, S. C. Panigraphy, D. W. Fuerstenau

The batch balling behavior of hematite, magnetite and limestone was found to depend markedly on the grinding method used for feed preparation. Wet ground materials require higher moisture for balling than do dry ground materials. Further, as the fineness of the wet-ground material is increased, the overall rate of agglomeration decreases, whereas the opposite is true for dry-ground materials. In contrast, the resulting pellet size distributions are not affected by the nature of the feed material preparation. These differences and similarities in the agglomeration behavior between wet and dry ground materials may result from the hydrophilic/hydrophobic nature of the surfaces, the formation of pre-agglomerates during dry comminution, and possible variations in the packing density of particles in the agglomerates.

Jan 1, 1978

By William R. Webster

This is a subject which our Institute has made peculiarly its own. In the first volume of its Transactions the analysis of steel received attention, and every subsequent volume has borne witness to the acuteness and industry of our members in the investigation of this subject. The keynote mas struck, in this as in so many other lines of progress, by A. L. Holley, in his paper on " Tests of Steel," read at the Easton meeting of October, 1873 (Trans., ii., 116)—an essay which may rank as a classic by reason of .its elegant form, logical force, and clear prevision of all the bearings of its theme, Taken together with the brief report of the discussion which followed it (in which Dr. Drown emphasized the effects of heat-treatment and mechanical handling, and Dr. Sterry Hunt the importance of minute variations in chemical composition, and of possible isomeric and allotropic conditions), it constitutes, after the lapse of twenty-five years, an admirable and adequate introduction to the long list of technical papers which have succeeded it. Three years later came the epoch-making papers of Dr. C. B. Dudley on the relation between the chemical composition and physical properties of steel rails, which, with the voluminous discussion they evoked, constitute a special volume, published by the Institute, and full of useful suggestions. If Dr. Dudley could be induced to resume this investigation, he would doubtless be able to solve many points still uncertain or disputed. But I cannot undertake to review the history of this subject, as represented in our Transactions—still less to restate all the contributions to it which have been made in books or in papers before other technical societies, since the initiative was taken by the Institute. My more modest purpose is to indi-

Jan 1, 1899

By R. C. Mahon

The Homer iron-ore mine is at Iron River, Mich. Because it covers a large area, 400 acres, and because there was a considerable depth of water in the glacial drift above most of the ore bodies, this mine has presented a number of unusual and often difficult operational problems. The purpose of this paper is to discuss a few of the most important problems encountered. Surface Water Mining on this property was started on one 40-acre tract. The ledge in this area was the highest on the property and, although it was a real problem, water could be handled by underground pumping. During the first period of mining, drifts were driven just under the ledge and holes were drilled through to the surface material. In later years these drifts have been extended wherever possible. Although these drifts assisted in the drainage problem, it was evident they would not be sufficient alone. Before mining on a large scale could be started on this property, the water problem had to be solved. A number of test holes were put down to the ledge, and showed that there was an average 150 ft. of water-saturated glacial drift above the ledge over the rest of the mine. The upper 70 ft. was gravel and sand and the lower 80 ft. clay and hard pan, with some narrow seams of sand and gravel. It was evident that the water above the clay seam could not be drained off through openings in the ledge and for that reason it was decided to install surface drainage wells. This method of drainage was entirely new at that time and was pioneered at the Homer mine. The sinking of the first well was started in June 1929. Immediately following the first well a number of wells were sunk, but only to the top of the clay seam. This was done with the idea that a greater capacity could be obtained in a shorter time from gravel seams where the water flowed more freely and that the cost of pumping the water above the clay seam would be considerably less than if the wells had all been sunk to the ledge at once. Before the drainage of surface water was started, 1200 gal. per min. against a head of 800 ft. was being pumped from the mine. By March of 1932, with five surface wells in operation, the mine pumping had been reduced to 150 gal. per min. At this time we were pumping 5000 gal. per min., under an average head of 110 ft. from the surface wells. The total pumping costs were 30 per cent less than in 1929 because the greater capacity was being pumped at a much lower head. From 1932 to 1936 the mine was idle and all surface pumping was stopped. Since 1936, 10 new wells have been added with a total pumping capacity of 8000 gal. per min. at the present time. The water level has been lowered 70 ft. since surface pumping was started in 1929, and it is now approximately at the top of the clay. To remove the water below the clay seam, 11 of the 15 wells were sunk to the ledge.

Jan 1, 1946