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By G. B. Misra

Though resistance to flow offered by mine airways supported with timber sets has been an object of study over the last half century, no accurate relation has yet been established from which prediction of the resistance coefficient of a projected timbered airway can be made. Zenofontowa et al. developed an empirical relation, but this relation has not been found to satisfactorily correlate experimental data obtained by Sales and Hinsley. This led the author to develop a set of simple theoretical relations between the resistance coefficient of timbered airways and the various parameters affecting it, such as the type and spacing of sets as well as the shape and size of members forming the set. Experiments were designed with the help of a laboratory model airway to verify the validity of the relations developed. With the experiments conducted so far with 4, 3 and 1-piece sets of 3.4 x 3.4, 2..5 x 2.5, and 4.5 X 4.5-cm square-section timbers in a 45.8 x 38-cm model airway, the theoretical relations have been shown to hold.

Jan 1, 1972

By AIME AIME

THE statements quoted below range widely over the field of contact between education and industry. 'Their sources are as indicated. True Education "Education must escape from its traditional warped and narrow views as to what constitutes life and preparation for life. It must train young men and women for vigorous, wholesome development of every important element of personality. It must build physical and mental health. For each student it must inform and discipline thinking in literature, in physical, bio- logical and social sciences, and in philosophy. It must awaken appreciation of beauty.

Jan 1, 1929

By Lauren A. Wright

General prosperity marked the industrial mineral industries of the U.S. and Canada in 1962. For most commodities, production and sales exceeded 1961 figures, and for several commodities, all-time production peaks were reached. Many millions of dollars were spent on exploration for and development of industrial mineral deposits, construction of new plant facilities, and expansion and modernization of existing plants. This generally satisfactory state is attributable mostly to a continuing high rate of building and heavy construction. However, for large segments of the industrial mineral field, 1962 was a year of increasingly severe competition and of problems, either existing or potential, of overproduction and overcapacity. Such problems are of particular concern to the asbestos, cement, potash and sulfur industries. As in years past, the trend continued toward larger-scale operations to permit lower production costs per unit of material mined, toward more stringent quality controls and toward marketing methods that provide greater efficiency and customer convenience.

Jan 2, 1963

By G. R. Wilms

A study has been made of the structural changes in polycrystalline high purity aluminum during the tertiary stage of creep under conditions of constant tensile load. It appears that there is no basic modification in the particular mechanism of deformation that characterized the preceding secondary stage of creep, but that the changes in crystalline structure produced during the tertiary stage are only a consequence and not a cause of the accelerated strain. Intercrystalline fissures were observed on entry into the tertiary stage, and these might supplement the accelerated rate of strain owing to local stress concentrations. There is evidence that the formation of these fissures may be associated with the presence of surface imperfections, and it is suggested that a more generalized treatment of the results may explain certain creep characteristics of commercial alloys. IN previous work'-4 a study was made of the changes produced when specimens of annealed aluminum were deformed at various temperatures and rates of strain, especially under conditions leading to creep under constant tensile load. It was shown that, as the temperature was increased or as the rate of strain was decreased, elements of the substructure produced within the grains became coarser, and with the strain rate constant at a given temperature, their size tended to an equilibrium value. The preliminary process of the breaking down of the grains into a substructure was identified with primary creep.' The subsequent equilibrium, condition was associated with secondary creep. The question then arose whether the tertiary stage corresponded to any further significant change in the substructure. The question is also of interest in view of the opinion, expressed for instance by Andrade,5 that the tertiary stage is merely an accelerated rate of strain due to the reduced area of section of a specimen under continuous tensile load, and the other opinion, as suggested by the observation by Sully, Cale, and Willoughby6 of a tertiary stage in com-pressive loading, that this third stage is a real effect in its own right. The object of this paper is to record some observations on the tertiary stage of high purity aluminum. Experimental Procedure The material was aluminum of 99.98 pct purity as previously used. The specimens had a rectangular section of l/8 x l/2 in., and extensions were measured over a 1 in. gage length. After machining to shape, the specimens were annealed to give a standard grain size of 0.2 mm and then electropolished. The general procedure involved metallographic and X-ray diffraction examination at progressive stages of elongation (marked by arrows on the curves shown in Figs. 1 and 2), the specimen being extended to fracture under constant load at a given temperature. The X-ray tests were made by the back-reflection method from a stationary specimen, using CoK radiation. The longer edge of the micrographs in the paper corresponds to the direction of applied stress. Results The previous work showed that, in the secondary stage of creep in aluminum, three basic types of structure could be developed according to the temperature and rate of strain. These were: 1—slip, which predominated at the lower temperatures and higher rates of strain and produced the finest and least perfect substructure; 2—cell structure, which superseded slip as the temperature was raised and the rate of strain decreased and which was characterized by a coarser and more perfect structure and an absence of slip lines; and 3—a stage termed "boundary microflow," which predominated at still higher temperatures and lower rates of strain when the cell size had increased and become comparable

Jan 1, 1955

By C. A. Bruch, W. E. McHugh, R. W. Hockenbury

Commercially pure molybdenum specimens were irradiated in the Materials Testing Reactor for an estimated exposure of 1.9 to 5.9x10 20 thermal nvt. Prior to irradiation, the material was ductile in the tension test; whereas after irradiation, it was brittle. The results of tension tests conducted at various temperatures revealed that the transition temperature for this material had been increased from —30' to +70°C as a result of the radiation exposure. From metallographic studies, it is concluded that the embrittlement is due to submicroscopic changes which raise the flow stress-temperature curve of the material. PRIOR to ten years ago, the bombardment of metals with high speed heavy particles such as protons, deuterons, a particles, and neutrons was primarily of academic interest. These particles existed in extremely small numbers in a few laboratories and only under very special conditions. With the introduction of the nuclear power reactors, these particles are now available in enormous quantities and it has become important from a practical standpoint to learn how well metals withstand severe reactor radiations. The principal radiations of concern in reactors are neutrons and y rays, since the heavier charged particles exist only in limited regions of reactors. Seitz,' in a theoretical approach, has shown that all of these high energy particles, except y rays, have enough energy to knock atoms from lattice sites and that these knocked-on atoms have enough energy to cause additional displacements of neighboring atoms. The result of this process would be a lattice containing many imperfections in the form of interstitial atoms and vacancies. Hence, it would be expected that the properties of metals can be changed by reactor radiations, and such has been found to be the case. Only a limited amount of data have been published in the open literature,2,3 and these data have been for relatively low integrated-neutron-flux exposures. In general, one effect of reactor radiations on the mechanical properties of metals has been to increase strength and decrease ductility. It is now possible to irradiate specimens in the Materials Testing reactor at much higher fluxes and to higher integrated exposures than previously possible.' The data which are being presented here describe the effects of a relatively high exposure on some mechanical properties of molybdenum. Experimental Procedures Material: The molybdenum used in this investigation was obtained from the Climax Molybdenum Co. The two heats from which the material originated were melted under a vacuum of 5 to 30 microns and cast in 7 in. diam water-cooled copper molds. One ingot contained 0.061 pct C and the other 0.066 pct. Both ingots were hot worked by extrusion and rolling into % in. diam rods, after which they were annealed and straightened. The rods were subsequently heated to 1100°C in a hydrogen atmosphere and swaged to ½ in. diam rods at the Research Laboratory of the General Electric Co. The resulting material had an average hardness of 264 VPN, or 99.2 Rb, and had an average of 5000 grains per sq ml in the transverse section, Test Specimens: Substandard-size tensile specimens were prepared according to the specifications shown in Fig. 1. These specimens were used also for hardness measurements. The metallographic specimens were small disks which were polished, etched, and photographed at X1000 prior to irradiation. The field studied was

Jan 1, 1956

By N. Malakouti, R. H. Whipp, O. A. Kuby, R. M. Smailer

A detailed description of the development of the FIOR process (Brown, Campbell, and Saxon, 1966) and, subsequently, other technical papers related to the operation and start up of the FIOR plant (Violetta, 1975; Whipp, 1980) are available in the technical literature. The Fluidized Iron Ore Reduction (FIOR) process plant constructed in the Matanzas region of Venezuela represents the first commercial application of this technology. The FIOR process was developed by Exxon Co. during the 1950s and 1960s. The facility in Venezuela was designed and constructed by Davy McKee, with plant start-up in 1976. While there is a minority government ownership in the company, FIOR de Venezuela operates as a private sector company with the majority of ownership being private capital. The FIOR process is well suited to utilize the naturally occurring iron ore fines of the Cerro Bolivar and San Isidro iron ore deposits located less than 100 km (62 miles) south of the plant site. Availability of natural gas within 150 km (93 miles) to the north, and a location bordering on the confluence of the Caroni and the Orinoco Rivers makes for an ideal geographic site. Feed stock to the FIOR plant consists of naturally occurring iron ore fines from these ore bodies, which are screened to -6mm (-0.2 in.) prior to drying in the ore preparation plant. A simplified flow plan is shown in [Fig. 1]. The dried ore is then transferred to the top of a structure containing four fluid-bed reactors located above one another so the mineral may flow from one reactor to the next by gravity. A reducing gas containing 90% hydrogen is made by steam reforming of natural gas, a CO shift

Jan 1, 1983

By E. Brunner, G. L. Hassler, T. J. Deahl

The capillary effects in reservoir rock are discussed in terms of the pressures they cause in sandstones and dolomites. Data for the two-phase case (oil-gas or water-gas) and for the three-phase case (oil, water and gas in rock) are used to demonstrate that in one sense the wetting preference of a rock depends on its saturation. The nature of capillary hysteresis is described for partially stable conditions, and the concept is enlarged. Reproducibly measurable pressures include the "capillary pressure," which is the pressure difference between any two phases that are each interconnected; the "threshold pressure," necessary to force a nonwetting phase through partially saturated rock; the "displacement pressure," which is that special case of the threshold pressure in which both phases fully saturate separate portions of the rock. Displacement pressure is equal to the minimum value of the "capillary pressure." The theory of flow including capillary forces is developed at the producing surface of a well to reveal the presence there of a pressure discontinuity in the gas (or other nonwetting) phase that can be controlled to the end that more oil may be poduced from an oil field. Experiments with packed sand-flow tubes having artificial producing surfaces support the theory. Introduction The basic surface quantities acting in an oil field are two: namely, surface tensions and contact angles. These are the quantities, variously expressed, and particularized as spreading forces, adhesion tensions, heats of wetting, etc., which are measured in the laboratory by techniques mostly confined to flat or circularly cylindrical surfaces. Such measurements have not had the extensive engineering application they seem to deserve because in most practical cases they are unavoidably compounded with the complex and unapproached subject of the internal shape of the interstices of rock. In this paper it is intended that the pressure differences developed in rock by capillarity be examined, defined, and given some engineering use in terms of some new measurements that have been made. Such pressure differences—namely, the capillary pressure, the displacement pressure and the threshold pressure—seem to provide a proper contact between the basic molecular quantities and the oil field. While certain modifications of usage will be undertaken, the present effort rests upon the background of work by the U. S. Geological Survey,l by Versluys, and especially by W. 0. Smith, 3,4,5 which has been reviewed recently in papers by Leverett.=s7 The most important concept of pressure difference is the capillary pressure, a function of saturation that expresses the pressure difference between the interconnected phases in a rock. It is often measured when water and air are the fluids present, but it can be measured with other fluids. A number of curves of capillary pressure have recently been measured by a method which it is intended shall be published in a later paper. Since heretofore capillary-pressure measurements upon rock have not been

Jan 1, 1944

By G. L. Hassler, E. Brunner, T. J. Deahl

The capillary effects in reservoir rock are discussed in terms of the pressures they cause in sandstones and dolomites. Data for the two-phase case (oil-gas or water-gas) and for the three-phase case (oil, water and gas in rock) are used to demonstrate that in one sense the wetting preference of a rock depends on its saturation. The nature of capillary hysteresis is described for partially stable conditions, and the concept is enlarged. Reproducibly measurable pressures include the "capillary pressure," which is the pressure difference between any two phases that are each interconnected; the "threshold pressure," necessary to force a nonwetting phase through partially saturated rock; the "displacement pressure," which is that special case of the threshold pressure in which both phases fully saturate separate portions of the rock. Displacement pressure is equal to the minimum value of the "capillary pressure." The theory of flow including capillary forces is developed at the producing surface of a well to reveal the presence there of a pressure discontinuity in the gas (or other nonwetting) phase that can be controlled to the end that more oil may be poduced from an oil field. Experiments with packed sand-flow tubes having artificial producing surfaces support the theory. Introduction The basic surface quantities acting in an oil field are two: namely, surface tensions and contact angles. These are the quantities, variously expressed, and particularized as spreading forces, adhesion tensions, heats of wetting, etc., which are measured in the laboratory by techniques mostly confined to flat or circularly cylindrical surfaces. Such measurements have not had the extensive engineering application they seem to deserve because in most practical cases they are unavoidably compounded with the complex and unapproached subject of the internal shape of the interstices of rock. In this paper it is intended that the pressure differences developed in rock by capillarity be examined, defined, and given some engineering use in terms of some new measurements that have been made. Such pressure differences—namely, the capillary pressure, the displacement pressure and the threshold pressure—seem to provide a proper contact between the basic molecular quantities and the oil field. While certain modifications of usage will be undertaken, the present effort rests upon the background of work by the U. S. Geological Survey,l by Versluys, and especially by W. 0. Smith, 3,4,5 which has been reviewed recently in papers by Leverett.=s7 The most important concept of pressure difference is the capillary pressure, a function of saturation that expresses the pressure difference between the interconnected phases in a rock. It is often measured when water and air are the fluids present, but it can be measured with other fluids. A number of curves of capillary pressure have recently been measured by a method which it is intended shall be published in a later paper. Since heretofore capillary-pressure measurements upon rock have not been

Jan 1, 1944

By Robert Livermore

It has been a noteworthy feature of the Cobalt camp, that many of the valuable ore deposits have been covered, wholly or in part, by small but usually deep lakes, such as Cobalt, Cart, and Peterson lakes, and with the subject of this article, Kerr lake. In the early days of the camp many water-covered areas, which have since been found to be valuable, were ignored or neglected by owners, or simply perfunctorily staked for water rights. Kerr lake is probably the evidence of a fault or sharp fold, having a general east and west strike, and containing a series of ore-bearing fissures, parallel generally to the strike, although having some notable exceptions to the general rule. On the north side of Kerr lake the formation is of diabase, while on the south side it is of Huronian slates and conglomerates. These Huronian measures extend out under the lake, dipping gently to the north to a lateral distance not yet definitely determined, owing to the lack of development under the deepest parts of the lake. Probably the contact between the diabase and Huronian or else between the former and the underlying Keewatin formation occurs somewhere near the center of the lake. Kerr lake originally covered 45 acres. Of this the Kerr Lake Mining CO. owned 12, the Drummond Mine, 7, and the Crown Reserve Mining CO. the remainder of 26 acres. Since the latter's property was originally entirely under water, it was necessary for the owners to make land for buildings and shaft room. Accordingly, in 1908, a trench was blasted out which deepened the outlet, and lowered the lake 8 ft. As many of the rich veins of the Crown Reserve and Kerr Lake companies were under water, mining was pursued under some disadvantages. Fortunately the rock is tight and solid, and mining has been done sufficiently fay from the surface to avoid unnecessary risk. Nevertheless, there was always danger of encountering open seams, through which too large a flow of water for comfortable working might come. Careful soundings were made over the veins, by means of steel-shod pipe, through mud and water to bedrock, but there was sometimes an element of uncertainty as to whether actual bedrock had been reached. Furthermore, the necessity of leaving safe backs between workings and lake tied up large quantities of ore, and made development in certain

Jan 1, 1915

John Eliot Allen has been made acting head, dept. of geology, New Mexico Institute of Mining and Technology, Socorro, N. Mex. He had been associate professor of geology. Robert B. Anderson has accepted a position with the U. S. Steel Co., Gary, W. Va., as assistant to the superintendent, No. 2 mine. [ ] Donald L. Archibald has joined the sales dept. of the Ellicott Machine Corp., Baltimore. He formerly had been associated with the Joy Mfg. Co., St. Louis. J. C. Boswell has been appointed manager of the Fairbanks dept., United Smelting Refining & Mining Co. J. B. Metcalfe has been appointed assistant to the president. G. Howard LeFevre was elected vice-president and general manager of metal sales and R. N. Hunt, vice-president and chief geologist was elected a director. R. B. Earling, vice-president and general manager of Alaskan operations, has retired but. will con¬tinue to serve on the board of directors. J. D. Crawford has been appointed general manager of Alaskan operations.

Jan 1, 1952

By R. E. Wade

The Butte, Anaconda & Pacific electrification is of peculiar interest, in an incidental way, to the entire mining fraternity, and especially the engineering branch, not only in this great Northwest country but throughout the entire Western mining country, which is rich in minerals and water power. It is probably fair to say that the prime object of mining and smelting engineering is to reduce the cost of production, and in the case in hand the relative location of mines and smelter brings the cost of transportation of ore to the front. While some might assign this item to the railway people, it is inseparably a part and parcel of the general scheme of the production of metal from the ore. In considering the electrification of the B., A. & P. railway the mining and smelting engineer, above all, wants to know what saving will be effected by the change in motive power. Unfortunately the new power has been in use during a very limited period and on the Smelter Hill section of the road only, and no reliable data, from actual service conditions, can be obtained until the entire electrified section has been in service for a reasonable length of time. Any remarks on this subject at the present time, therefore, must of necessity be general in nature and more or less descriptive. The railway, electrical and mining worlds and the country in general are indebted to the B., A. & P. railway for the pioneer work it is now doing, as it undoubtedly marks the beginning of the electrification, within the comparatively near future, of all transcontinental roads between the Missouri river and the Pacific coast. Together with this goes the development of an untold wealth in water power and all natural resources within the same territory. For the first time in the history of electric railway work, in this country, direct current at a potential of 2,400 volts is being used. With this potential there is a great saving in transmission of energy to the locomotives and there are only two substations, one at either end and 26 miles apart, for supplying the power for the movement of trains of heavy tonnage over the main line and for switching movements at terminal and intermediate yards, and comparatively little feeder copper is required.

Jan 1, 1914

By R. E. Wade

THE Butte, Anaconda & Pacific electrification is of peculiar interest, in an incidental way, to the entire mining fraternity, and especially the engineering branch, not only in this great Northwest country but throughout the entire Western mining country, which is rich in minerals and water power. It is probably fair to say that the prime object of mining and smelting engineering is to reduce the cost of production, and in the case in hand the relative location of mines and smelter brings the cost of transportation of ore to the front. While some might assign this item to the railway people, it is inseparably a part and parcel of the general scheme of the production of metal from the ore. In considering the electrification of the B., A. &. P. railway the mining and smelting engineer, above all, wants to know what saving will be effected by the change in motive power. Unfortunately the new power has been in use during a very limited period and on the Smelter Hill section of the road only, and no reliable data, from actual service conditions, can be obtained until the entire electrified section has been in service for a reasonable length of time. Any remarks on this subject at the present time, therefore, must of necessity be general in nature and more or less descriptive. The railway, electrical and mining worlds and the country in general are indebted to the B., A. & P. railway for the pioneer work it is now doing, as it undoubtedly marks the beginning of the electrification, within the comparatively near future, of all transcontinental roads between the Missouri river and the Pacific coast. Together with this goes the development of an untold wealth in water power and all natural resources within the same territory. For the first time in the history of electric railway work, in this country, direct current at a potential of 2,400 volts is being used. With this potential there is a great saving in transmission of energy to the locomotives and there are only two substations, one at. either end and 26 miles apart, for supplying the power for the movement of trains of heavy tonnage over the main line and for switching movements at terminal and intermediate yards, and comparatively little feeder copper is required.

Jan 11, 1913

By John D. Ridge, Betty S. Moriwaki

The significant chromite producers listed in Table I11 are not major steel producers, with the exception of the USSR. After manganese, chromium is the most important alloying metal in steel. It would not be surprising to find a direct relationship between steel production and chromite imports. The precise connection is concealed by the other uses of chromite and the grades of steel produced by the various countries involved. In addition, the amount of ferrochromium made for export must figure in any calculation. Norway, a producer of considerable amounts of ferromanganese, imports significant quantities of chromite for ferrochromium manufacture. Most of the ferrochromium is exported to European steel- producing nations. Sweden imports only half as much chromite as Norway but makes far more chromium-bearing steel. Thus Sweden has far less ferro-chromium for export, although it supplies about 2000 tons per year to the U.S. and probably some- what more to such chromite-poor steel producers as Germany and Belgium-Luxemburg.

Jun 1, 1955

By Philip J. Shenon

IN 1947 the mining industry strove desperately to regain operating normalcy. During the first part of the year the industry in this country was plagued with labor shortages, strikes, and portal-to-portal lawsuits. Then followed the uncertainty of Government policy with respect to subsidies and tariffs; and the long and bitter controversy as to whether we are a nation of mineral "haves" or "have-nots." As the year progressed the labor supply impoved somewhat and the Taft-Hartley law brought partial relief to strike-troubled industry. The uncertainty with respect to tariffs was partly answered by President Truman on April 29 when he announced the suspension of the 4¢ import duty on copper until March 31, 1949, and later, near the close of the year, by the announcement of the tariff agreement signed by the United Nations at Geneva. By this agreement tariff rates are to be adjusted downward, or "bound" at their present levels, for three years, on commodities amounting to some 60 per cent of United States trade. Effective Jan. 1, 1948 the rate of duty will be substantially reduced on ores, concentrates, or metals of zinc, aluminum, copper, manganese, tungsten, iron, steel, barytes, nickel, cadmium, and antimony.

Jan 1, 1948

Jan 1, 1968

By P. M. Blair, D. W. Peaceman

The shape and position of the gas-oil transition zone during downdip displacement of oil by gas has been calculated using flow equations which include the effects of gravity, relative permeability, capillary pressure and compressibility of the fluids. The calculations treat the problem in two space dimensions, and results are compared with data from a laboratory model tilted at 30° and 60° from the horizontal on displacements near and above the maximum rate at which gravity segregation prevents channeling of the gas along the top of the stratum. The good agreement between calculated and experimental results demonstrates the validity of the tecbnique as well as that of the flow equations. INTRODUCTION Knowledge of the fluid distribution and movement in an oil reservoir is important in producing operations and estimation of reserves. The history of the oil industry has included steady progress in improving the accuracy of calculations which provide the required knowledge. The earliest method of calculating reservoir performance consisted of material-balance equations based on the assumption that all properties were uniform throughout a reservoir.l For many reservoirs such a simple formulation is still the most useful. However, when large pressure and saturation gradients exist in a reservoir, the assumption of uniform values throughout may lead to significant error. To reduce these errors, Buckley and Leverett2 introduced a displacement eqation which considers pressure and saturation gradients. Methods available at that time permitted solutions to the Buckley-Leverett equation in one space dimension; these solutions have been very useful in solving many problems related to the production of oil. However, the one-dimensional methods are not adequate for systems in which saturations vary in directions other than the direction of flow. An example of such a system is the case of gas displacing oil down a dipping stratum in which the gas-oil contact becomes significantly tilted. Of course, the Buckley-Leverett displacement method cannot predict the tilt of the gas-oil contact. Recent improvements3,4 of the one-dimensional Buckley-Leverett method achieve some success in predicting the tilt of the gas-oil contact at sufficiently low flow rates. However, at rates high enough that the viscous pressye gradient nearly equals or exceeds the gravity gradient, even these improved one-dimen,sional methods incorrectly predict the shape and velocity of the contact. Further progress in estimating such fluid movements in a reservoir appears to require consideration of the problem in more than one space dimension. The recent two-dimensional method of Douglas, Peaceman and Rachford5 appears adaptable to calculate changes with time of the saturation distribution in a vertical cross-section of a reservoir. The movement of saturation contours should represent the moving fluid contacts and include the effects of crossflow due to gravity, as well as variations in the rock and fluid properties. The nonlinear nature of the equations used in the method has prevented proof of the validity of the solutions. Douglas, Peaceman and Rachford made some comparisons with experiment but did not include cases in which gravity was important nor cases involving displacement by the nonwetting phase.For these reasons, a test of the two-dimensional method for a case in which these factors are included would be very desirable. The test selected was a comparison of calculated results with those from a carefully controlled laboratory experiment on a model with measured physical properties. The model selected was one in which gas displaced oil down a tilted, rectangular sand pack. The model can be thought of as representing a vertical cross-section taken parallel to the dip of a reservoir. The displacement thus simulates gas displacing oil downdip that might result from gas-cap expansion or gas injection. This report outlines the calculation method used

By L. R. Jackson, W. T. Lankford, K. F. Smith

ComMercial steel sheet is prepared by a combination of hot and cold rolling and annealing. This treatment usually results in more or less pronounced anisotropy. The anisotropy may manifest itself both as preferred orientation and in the manner in which impurities, segregations, and the like, are aligned in the sheet. The type of preferred orientation and the organization of impurities or segregations may affect the elastic moduli, the yield strength, the tensile strength, and almost always the amount of ductility in different directions. In any case, the most important directions concerned in the anisotropy are along the rolling direction, along the width direction, and along the thickness direction. Considerable data exist on the anisot-ropy of sheet steel as demonstrated by conventional tensile tests; however, few attempts have been made to measure the constants of plastic anisotropy and use them to describe the flow of anisotropic sheet under combined stresses. In this paper, evidence is presented indicating that plastic flow in anisotropic sheet can be described by the shear-strain energy flow theory provided that the anisotropy is properly taken into account. Materials Used in the Investigation Table I lists the sheet materials used in this investigation and describes the condition in which materials were tested. Direction, of Tests and Test Methods Two types of tests were run—tensile tests and hydraulic-bulge tests. Characteristic parameters of anisotropy were determined from the tension tests by methods which will be described later. In all cases, the tensile test pieces were cut from the same quarter line and adjacent to the bulge test pieces in the sheet in order to minimize

Jan 1, 1949

By J. J. Thomas

THIS investigation was undertaken to determine, if possible, the relation between static and dynamic tensile tests as measured by the work required to break test specimens slowly, in a tensile testing machine, and rapidly, by means of a falling weight. It was hoped that the investigation would throw some light on the role played by ductility under different rates of application of load. FIG. 1.-STRESS-STRAIN DIAGRAM. In problems of design, it is usually assumed that the moduli of elasticity of all steels are equal; viz., about 30,000,000. The stress-strain diagram within the elastic limit is a straight line, as shown in Fig. 1, where OA is the curve of a hard steel and OB that of a soft steel. If the modulus of elasticity is constant, as assumed, the slope of the line OC

Jan 2, 1921

Jan 1, 1967

Jan 1, 1959