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By T. L. Fritzlen

Extrusion of aluminum alloys in this country is performed mainly by direct extrusion, therefore this paper is confined only to factors affecting the rate of extrusion by this method. Many factors affect the rate of extrusion of aluminum alloys. It is the purpose of this paper to present a discussion on the factors that are subject to technical control. Most of them are closely related, so that a clear-cut distinction between them is rather difficult. However, an attempt will be made to evaluate the effect of each factor separately, as far as possible. The most important factors only will be considered, and these will be discussed in detail under three general headings: (I) characteristics of the equipment, (2) size and structure of the ingot, and (3) temperature of ingot, cylinder, and other parts. It is a well established fact1 that the pressure and the speed of extrusion are related and are exponential functions of one another. Therefore, whenever a certain condition tends, for instance, to increase the pressure required for extrusion, it will reduce the extrusion speed if the pressure is maintained constant. For this reason, in this paper the effect of various conditions is expressed either in regard to their effect on the pressure required or the extrusion speed. Another established fact is the relation- ship between the temperature of the material being extruded and the pressure required to extrude. According to Schi-shokin,= this relationship is of the exponential type, and as the temperature is increased the pressure required is decreased. It would seem from the preceding that the greatest rates of extrusion can be obtained by the use of higher temperatures. However, as is well known, other factors intervene to limit the rate of extrusion of aluminum alloys when increasing the temperature. These factors will be discussed in detail later. Characteristics of the Equipment The capacity of the press determines * the maximum unitary pressure that can be applied for any given cylinder diameter. Pressures used for extrusion of aluminum alloys range from approximately 50,000 lb. per sq. in. to 150,000 lb. per sq. in., dependent upon the alloy and the size of the shape extruded. Higher pressures could be used to advantage, but existing steels limit pressures employed in the production of extrusions. Numerous mechanical characteristics of the extrusion press affect extrusion rate. The most important characteristics of the press itself are: (I) sensitivity of the main pressure valve and accuracy of pressure gauges, (2) accuracy of equipment to heat the cylinder uniformly and to control cylinder temperature, and (3) accuracy of means of measuring the speed of extrusion. The variables subject to control during the extrusion operation are pressure, temperature, and speed, and it is evident that the preceding characteristics

Jan 1, 1946

By P. W. Andrews, R. B. Toombs

ECONOMIC STRUCTURE OF MODERN INDUSTRIAL ECONOMIES The role of minerals in modern industrial economies may be examined in several ways. There are relationships with the various sectors of the economy: the primary, secondary, and tertiary industrial groupings and activities. Mineral supply and demand activities can be measured in terms of national accounts criteria. The economic policy objectives of the modem industrial economy are based to a considerable extent on the needs of the nation for economic supplies of miner- al materials. There is an important role for minerals relative to national security in peace and in wartime and many national policies are directed toward ensuring adequate sup- plies of minerals. Environmental control in the modem industrial economy is increasingly concerned with matters related directly to the production and use of minerals and these matters, in turn, bear importantly on conservation in mineral supply and demand. Mineral polices include specific provision for research and development activities concerned with the production and the use of minerals. In all, national policy objectives will be shaped in considerable part by the circum- stances of mineral supply and demand: the relative degree of availability from domestic and foreign sources, the state of the mineral-processing industries, and the degree of development of the mineral-using industries, and per capita and total changes in requirements. Goods made from mineral raw materials are the basis of all advanced societies and although this is taken for granted, every country is continually dealing with problems of mineral supply and demand. Considering that in the first 50 years of this century the consumption of mineral materials in a highly Industrialized country such as the United States increased by six times while the population was doubling, it becomes apparent that if a country is to enjoy rapid economic growth it must have access to huge and ever-growing supplies of mineral materials at lowest possible cost. Adequate supplies of mineral materials and wise usage of mineral resources have always been among the most important determents of a nation's survival The importance of access to adequate mineral supplies is increasing every year and this has significant international, as well as national, implications because of the unique locational characteristics of mineral resources. It is generally acknowledged that no particular type of natural resource is essential to a high level of national income or to economic progress. A country's endowment of natural resources need not exercise a determining influence on the course of its national income over time, provided it is able to trade. What is required for economic progress is the availability of a substantial quanti-

Jan 1, 1976

By Homer Griffield Turner

The nature and comparative features of anthracite and bituminous coals have been discussed by the writer in two previous papers.' Although this paper is offered as a further contribution to the subject, it seems desirable at the outset to repeat some of the descriptive matter of the early works in order to show the actual connection between various constituents of both coals and the new photomicrographs and other physical and chemical properties. Structure of Anthracite and Bituminous Coals A lump of bituminous coal (Fig. 1) is readily seen to be composed of layers differing from one another in texture, luster and thickness. There are, in general, three kinds of layers, although only two are usually seen. One is deep black, very compact, and has a bright luster; another is grayish black, has a duller luster and is less compact; the third is black, dull and porous in appearance, but because of its thinness is not often seen except on parting surfaces. This last material is charcoal. American students of coal morphology use the names anthraxylon, attritus, and fusain to designate these three constituents of laminated coal. Anthraxylon refers to the brightest bands, attritus to the duller layers, and fusain to the charcoal. Close examination of a lump of bituminous coal shows the brightest deep black layers to be embedded in the duller grayish black laminae. These deep black layers are lens-shaped and vary in thickness from thin sheets to over half an inch. They are often so continuous through the lump that their tapering terminae are not noticeable. On careful examination the duller grayish black laminae (Fig. 7) are seen to contain many very thin sheets of this very bright black material. The charcoal

Jan 1, 1930

By Charles White Merrill

Mankind's progress is measured in minerals. Man's emergence from prehistory is marked by passage through a Stone Age and a Bronze Age and into the present era, sometimes called the Iron Age or the Age of Metals. With the evolution of civilization and the development of a modem industrial economy, minerals become more and more important. Structures, roads, and machines are built largely of minerals; the energy to heat the structures and to drive the machines is mostly mineral; agricultural fertility is maintained by mineral fertilizers and water; and military strength is provided by fortresses, armaments, and munitions, largely of mineral origin. Thus in the material world, in the productivity of the economy, access to minerals has paramount importance. Every evidence indicates increasing dependence on minerals in the modem economy, particularly on the mineral fuels as energy sources to provide the power base for advancing industrialization. Both the total and the per capita consumption of almost every mineral is increasing in the industrialized nations. Moreover, nations with predominantly agrarian economies call themselves underdeveloped and universally strive to industrialize. Most mineral consumption trends in the more advanced economies have been greatly exceeding population growth-which itself has been advancing at an accelerating rate-and sometimes have surpassed the growth in real income. Some minerals have only recently been adopted or grown to importance in use. Titanium metal did not appear as a commercial product until 1948, and even coal seriously displaced wood as a source of heat less than two centuries ago. On the other hand, minerals have always played an important role in construction. The prehistoric megaliths that form the dolmens of Salisbury Plain are stone; the pyramids are andesite faced with limestone; and many other ancient structures are built of mineral materials. In modem times the whole course of architecture has been redirected by new building materials, mostly mineral. Most conspicuous is the sky-

Jan 1, 1964

By Thomas Read

AMONG the large number of deep mines in the world there are several which do not differ much in depth. The St. John del Rey mine, in Brazil, has reached a vertical depth of 6726 ft. below the top of its shaft; miners enter it, however, through an adit which intersects the shaft 324 ft. below its top, wherefore it might be said that the mine is really only 6400 ft. deep. In the Kolar gold field of India there are a number of deep shafts, one of which reaches to a vertical depth of 6140 ft. below surface. In South Africa also there are a number of deep shafts, the Village Deep being 6100 ft. early in 1921. The City Deep, Ltd., proposes to sink to a depth of 7000 ft. but pre-sumably by the time it does so the St. John del Rey will be deeper than that, since it has been increasing in depth at an average rate of about 150 ft. per year. The deepest shaft in the United States, the Tamarack No. 5, although it is only 5308 ft. deep, actually approaches nearer to the center of the earth (4100 ft. below sea level, as against 3958 ft. , at St. John del Rey). The deepest workings in the Calumet & Hecla go down to 4600 ft. below sea level. The St. John del Rey is not only the deepest, mine in the world, but it also is worked by the oldest registered English mining company, which was organ-ized in 1830 to work a mine at a considerable dis-tance from this one. That mine proved unprofitable, and in 1837 operations were transferred to the. deposit now under discussion, where operations have been prac-tically continuous ever since.

Jan 6, 1923

By A. W. Gauger

IT is with some trepidation that I approach my subject, for I know that I shall at once incur the suspicion of the mechanical engineer, with his concern for boiler tests and efficiencies; of the mining engineer, with his mechanization problems; and of the chemical engineer with his unit processes. Nevertheless, it must be recognized that the technology of fuels, the systematic body of knowledge relating to the production, processing and utilization of mineral fuels, has grown to such proportions and involves so many widely diverse applications of fundamental science and engineering that it behooves us to stop and consider just what its status is in relation to other technologies, as well as in relation to the present and future needs of the social order. The time has come when technologists, applied scientists and engineers must consider the possible effects that their achievements may have 0n Society. The development of a machine to replace several hundred men is a fine achievement when considered solely from the point of view of creative endeavor. But what of the men who are displaced by the machine! Does not the responsibility for the development of this machine embrace as well the consequences of obsolescence and technological unemployment resulting from such development? I believe that it does and that we must recognize this fact in our practice of engineering and technology as well as in the training of future engineers and technologists. MAGNITUDE OF THE FUELS INDUSTRY Fuel technology is the body of knowledge that relates to the mineral fuels. The fuels industry is by far the most important of all our mineral industries. The chart in Fig. I, reprinted from U. S. Bureau of Mines Information Circular No. 6643, indicates the comparative values of metals, fuels and other nonmetallic minerals for the year 1929. Of the grand total of 13 1/4 billions of dollars in value of minerals at the mines, the mineral fuels contributed 48 per cent. Coal, with 34.4 per cent, exceeded the value of any other single mineral. In fact, the value of the production of the Pennsylvania anthracite mines alone annually exceeds the value of the gold production of the entire world. Petroleum and natural gas in 1020 contributed 14.3 per cent and 3.3 per cent, respectively, of the total value of world mineral production. So much for the world picture; let us now look at the situation in the United States. Over the 60-year period 1880 to 1939, $46,409,727,000 of metallic products, S80,788,852,000 of fuels (coal, petroleum, natural gas, natural gasoline) and $27,871,000,000 of nonmetallic minerals other than fuels were produced. The mineral fuels have contributed 52.7 per cent of the entire mineral wealth produced over this period that has seen such tremendous industrial development in our country. As a matter of fact, our present industrial civilization has been made possible through the use of the

Jan 1, 1942

By Thomas A. Read

The internal friction of single crystals of metals is affected markedly by a variety of factors, which, according to the literature, are without influence on the internal friction of polycrystalline metals at strain amplitudes less than 10-5. For example, the internal friction of a suitably oriented zinc single crystal is multiplied by a factor of ioo when the vibration amplitude is slightly increased, and the internal friction of a copper crystal is markedly increased by the application of a stress of 30 lb. per sq. in. for one minute. In this paper it will be shown that these, together with the other phenomena associated with the damping of mechanical vibrations in metal single crystals, can be satisfactorily explained, at least qualitatively, in terms of an atomic mechanism that has been proposed for quite another purpose—that of accounting for slip in metals. The extraordinary agreement between the observed behavior of the metal single crystals and the behavior that could be predicted on the basis of this atomic mechanism leads to the belief that the latter is probably essentially correct. If this is so, it follows that valuable information about the slip process in metals may be gained from measurements of internal friction on single crystals. In this paper the results of the only study to date on the damping of mechanical vibrations in single crystals of metals mill be presented. Experimental Procedure The internal friction of a material is a measure of the rate at which the energy of mechanical vibrations is converted into heat. The measure of internal friction used in the present paper is the decrcment A, which is defined as the fraction of the energy of vibration lost per half cycle. The measurements described here were made for longitudinal oscillations at a frequency of 33.5 kc. for the copper crystals, and at a frequency of 39 kc. for the zinc crystals. The method used is that of the composite piezoelectric oscillator. The single-crystal specimens are in the form of circular cylinders M in. in diameter and I 1/2 to 21/2 in. long. The crystal rods are waxed in a V-block and sawed to the proper length with a fine jeweler's saw. The ends of the specimen are ground flat, and one end is cemented with a very thin film of beeswax and rosin to the end of an x-cut quartz rod which is 1/4 in. in diameter and 3 in. long. The length of the specimen rod is determined by the condition that its natural frequency for longitudinal vibration be the same as that of the quartz rod, within 0.5 per cent. The lengths of the specimens are thus different for different orientations of the cylinder axis with respect to the crystallographic axes. When the specimen and quartz rods are thus matched in frequency the adhesive is at a node of stress, and it has been shown experimentally that under these circumstances

Jan 1, 1941

By Thomas A. Read

The internal friction of single crystals of metals is affected markedly by a variety of factors, which, according to the literature, are without influence on the internal friction of polycrystalline metals at strain amplitudes less than 10-5. For example, the internal friction of a suitably oriented zinc single crystal is multiplied by a factor of ioo when the vibration amplitude is slightly increased, and the internal friction of a copper crystal is markedly increased by the application of a stress of 30 lb. per sq. in. for one minute. In this paper it will be shown that these, together with the other phenomena associated with the damping of mechanical vibrations in metal single crystals, can be satisfactorily explained, at least qualitatively, in terms of an atomic mechanism that has been proposed for quite another purpose—that of accounting for slip in metals. The extraordinary agreement between the observed behavior of the metal single crystals and the behavior that could be predicted on the basis of this atomic mechanism leads to the belief that the latter is probably essentially correct. If this is so, it follows that valuable information about the slip process in metals may be gained from measurements of internal friction on single crystals. In this paper the results of the only study to date on the damping of mechanical vibrations in single crystals of metals mill be presented. Experimental Procedure The internal friction of a material is a measure of the rate at which the energy of mechanical vibrations is converted into heat. The measure of internal friction used in the present paper is the decrcment A, which is defined as the fraction of the energy of vibration lost per half cycle. The measurements described here were made for longitudinal oscillations at a frequency of 33.5 kc. for the copper crystals, and at a frequency of 39 kc. for the zinc crystals. The method used is that of the composite piezoelectric oscillator. The single-crystal specimens are in the form of circular cylinders M in. in diameter and I 1/2 to 21/2 in. long. The crystal rods are waxed in a V-block and sawed to the proper length with a fine jeweler's saw. The ends of the specimen are ground flat, and one end is cemented with a very thin film of beeswax and rosin to the end of an x-cut quartz rod which is 1/4 in. in diameter and 3 in. long. The length of the specimen rod is determined by the condition that its natural frequency for longitudinal vibration be the same as that of the quartz rod, within 0.5 per cent. The lengths of the specimens are thus different for different orientations of the cylinder axis with respect to the crystallographic axes. When the specimen and quartz rods are thus matched in frequency the adhesive is at a node of stress, and it has been shown experimentally that under these circumstances

Jan 1, 1941

By R. W. Gurry

WHEN a steel in the austenitic state, with all its carbon in solution, is maintained, at constant temperature, in contact with a gas that removes the carbon from the surface, yet without otherwise altering the composition of the steel, the change in weight of the specimen, after any period of exposure, is a direct measure of the amount of carbon it has then lost. The purpose of the present paper is to show how, by application of established mathematical reasoning based on the fundamental diffusion law and on certain postulates, this loss of weight yields a complete picture of the distribution of carbon throughout a specimen of regular shape after any period of exposure, with all the accuracy required in any practical occurrence of decarburization. Precisely the same is true for the gain in weight during the reverse process of carburization, or for the gradual gain or loss of any element, so long as the steel comprises only a single phase at temperature, provided always that the experimental conditions conform to the postulates. The change in carbon content from surface to center of the specimen is always continuous, when everything is in solution, even though under the microscope the decarburized zone (or carburized rim) may appear to be sharply defined. The experimental procedure is described and some typical results are presented, which are then interpreted by application of the diffusion law. EXPERIMENTAL PROCEDURE Initially an endeavor was made to follow the gain of weight during the process of carburization in a hydrogen-toluene atmosphere, but it was soon found that the specimen became coated with graphite, which could not be removed without some loss of metal; therefore it was decided to continue carburization until the steel was saturated throughout, to remove all graphite from the surface of the specimen, and then to follow the loss of weight during decarburization in a moist hydrogen atmosphere at the same temperature as that used for carburizing. The carburizing procedure has been described in an earlier paper;1 it suffices to state here that the carburization lasted about 140 hr. at 760°C. (1760°F.) and 44 hr. at 1110°C. (2030°F.), these periods being long enough-on the basis of the calculations presented later-to ensure that the specimen was about 99.9 per cent saturated at each temperature. The specimen was a cylinder about 3.8 cm. long and 0.475 cm. in diameter; the materials were carbonyl iron, a commercial low-metalloid iron, and a steel with 3.6 per cent nickel and the usual proportion of other elements. The fully carburized specimen, after cooling at the top of the furnace tube, was placed in a lathe and sandpapered to remove all graphite; then the diameter was measured with a micrometer caliper, and the initial weighing (corresponding to complete saturation) was made. By means of a

Jan 1, 1942

By H. I. Aaronson

Isothermally formed plates of proeutectoid a, lengthen at approximately the rates predicted by the Zener-Hillert equation, indicating that their lengthening kinetics are controlled by the volume diffusion of chromium in the ß matrix. Solution annealing treatments in the vicinity of the transus introduce a second mode of transformation, in which the lengthening rate is at least 1.8 x 104 faster than predicted by this equation. Little or no volume diffusion appears to accompany the latter transformation. The Presence of oxygen is evidently a Prerequisite for the occurrence of this reaction. X HE effects of thermal history prior to the initiation of transformations which proceed by nucleation and diffusional growth are currently evoking considerable interest. The rate of nucleation (but not the rates of growth) of pearlitel and of bainite,2 and the over-all rates of aging reactions in Al-cu3 and Al-si4 alloys have been shown to be appreciably dependent upon thermal history in the solid-solution region"' or in the two-phase region prior to the onset of pre~ipitation.3,4 In none of these reactions, however, was the transformation mechanism changed by variations in the temperature-time path used to reach the reaction temperature. Preliminary experiments reported by M. K. McQuillan5,8 and a systematic investigation by Farrar and Margolin7 have disclosed that the transformation behavior of hypoeutectoid Ti-Cr alloys is considerably more sensitive to thermal history. Qualitative evidence strongly suggests that not only the rate of nucleation but also the rate of growth and even the mechanism of the ß — a reaction can undergo remarkable changes when a solution annealing treatment in the vicinity of the ß/a +ß, or transus temperature, is interposed between a high-temperature solution anneal (conventionallq at 1000°C) and the isothermal reaction treatment. The present investigation was undertaken in an attempt to ascertain the nature and origin of these effects. Study of the changes in the kinetics and morphology of the ß - a, reaction produced by varialtions in thermal history was the primary means employed for this purpose. EXPERIMENTAL PROCEDURE The compositions of the alloys used in this in~esti~ation are given in Table I. These alloys were homogenized for 5 days at 1050° C in evacuated (2 x 10 -5 mm of Hg), zirconium-gettered fused quartz capsules. The capsules themselves were enclosed in a porcelain chamber evacuated with a mechanical pump during the homogenization anneals. Upon completion of homogenization, the alloys were cooled to room temperature and then reheated to 550°C for 3 1/2 days in order to transform the alloys to a finely divided mixture of a and TiCr2, and thus provide an approximately constant initial mi-crostructure. Individual specimens were sealed in evacuated and internally gettered Vycor capsules and heat treated as previously described.8,9 EXPERIMENTAL RESULTS Ti-10.64 Pet Cr. This investigation was largely performed on the 0.64 pet Cr alloy. The "base"

Jan 1, 1962

By Yves Dardel

THE literature concerning the remelting of aluminum and its alloys is very rich. Unfortunately the greater part of the papers about this subject have no scientific value, for the theories or explanations are too often in opposition to the laws of physical chemistry. Furthermore only a few of the methods of purification1,2 are considered in the literature. Hence it has seemed necessary to the author to sketch a general theory of the purification of secondary aluminum. The purpose of the purification is to eliminate the impurities that the charges and the atmosphere of the furnaces bring into the bath during the successive remeltings. Indeed scrap as well as metal can be used when soiled with oil, greases, water, .. , if it has been sufficiently dried and contains oxides. At the melting point of the metal, the oils and greases are decomposed into their constituent elements H2, 02, H2O, C02, CO, CH4, and others. These gases are added to the corresponding gases in the atmosphere of the furnace. The impurities introduced into the metal during the remelting will accordingly be the products resulting from the action of these gases on the liquid bath. The quantity of hydrogen that is soluble in aluminum and its alloys is given by the relation of Sieverts3 as a function of its partial pressure PH2 in the atmosphere [m = K _%/PH, [I]] where K is a constant, which depends only upon the temperature and increases with it. The experiments of Röntgen and Braun4, Röntgen and Möller5, Bircumshaw6 and Winterhager7 have rendered it possible to determine the value of K, when the temperature is inferior to 1.000°K. One obtains: [log K = - 4,702.5 + 0.238 [2]] Besides its usual signification, the term PH2 represents also the internal pressure of dissolved hydrogen, since in the equilibrium, that is, when no gas exchange occurs between the two phases, the pressures of hydrogen in the metal and in the atmosphere must be equal. Eq I shows that when the partial pressure of H2 increases the amount of dissolved hydrogen in equilibrium increases, and that, if the contrary occurs, the quantity of H2 should diminish. However, if for any reason the diffusion of hydrogen is hindered and the total amount of dissolved gas remains constant while the temperature lowers, the internal pressure of H2 increases until it reaches the value of the hydrostatic pressure. At this point, bubbles of hydrogen appear in the bath and escape out of it. The amount of hydrogen in the metal is then limited by a maximum depending on the hydrostatic pressure, which is practically equal to one atmosphere. Indeed hydrogen does not accumulate in the form of a hydride appearing as a separate solid phase. However, even the mechanism of the solubility is not yet elucidated. One does not know exactly as yet, whether the

Jan 1, 1947

By Carlton Beal

This paper presents useful charts for conversion of various viscosimeter units into centipoises and graphically summarizes published investigations of the viscosity of air, water and natural gas at high temperatures and pressures. Where possible, charts and correlations were constructed to cover a range of temperature (60°F. to 300°F.) and pressure (14.7 lb. per sq. in. abs. to 8000 lb. per sq. in. gauge) encountered in oil fields. Correlation charts, for the purpose of predicting crude oil viscosity and solubility behavior at oil field temperatures and pressures, were constructed from an analysis and correlation of 1332 viscosity and solubility observations from 953 crude oil samples taken from 747 oil fields. Of these fields, 501 are in the United States, including 75 in California. Of the 1332 observations, 1215 were viscosity values, including 786 of gas-free crude oil, 351 of oil saturated with gas, and 78 under-saturated with gas at pressures above the bubble point. Results show that crude oil viscosity at various reservoir conditions can be predicted with average deviations varying from 24.2 per cent for gas-free crude oil to as little as 2.7 per cent for undersaturated crude oil "above the bubble point." The solubility of crude oil may be predicted from oil gravity and saturation pressure with an average deviation of 22.0 per cent from observed values. In conclusion, it is shown that the viscosity of a gas and gas-saturated crude oil may be predicted within the accuracy of most reservoir computations. Viscosity is a measure of flow resistance; common units are in centipoises (cp.). The object of this report is to present conversion charts and simplified 'correlation charts showing the viscosity behavior of air, water, gas and crude oil and gas-saturated crude oil under oil field temperatures and pressures, which have been known to be as high as 300°F. and 8000 Ib. per sq. in. gauge under subsurface conditions. The viscosity of a liquid or gas is important because it is a measure of its fluidity, or its ability to flow through pipe lines or oil sands. Viscosity of air has become important because it is being used in secondaryl,2 recovery projects. The viscosity of natural gas and water at reservoir conditions is useful because they are almost universally associated and produced with crude oil. The viscosity of gas-saturated crude oil at reservoir pressures and tem peratures is of particular value in making estimates of oil reserves3 and rate of oil recovery from flush pools when production decline data are limited. Instruments Used to MeasuRe Viscosity There are many types of viscosimeters,4 and the instruments most commonly used to measure the atmospheric viscosity of liquids at moderate temperatures and their practical working ranges have been deScribed5,6 in detail. Fig. I and Fig. 2 are viscosity conversion charts which have

Jan 1, 1946

By Carlton Beal

This paper presents useful charts for conversion of various viscosimeter units into centipoises and graphically summarizes published investigations of the viscosity of air, water and natural gas at high temperatures and pressures. Where possible, charts and correlations were constructed to cover a range of temperature (60°F. to 300°F.) and pressure (14.7 lb. per sq. in. abs. to 8000 lb. per sq. in. gauge) encountered in oil fields. Correlation charts, for the purpose of predicting crude oil viscosity and solubility behavior at oil field temperatures and pressures, were constructed from an analysis and correlation of 1332 viscosity and solubility observations from 953 crude oil samples taken from 747 oil fields. Of these fields, 501 are in the United States, including 75 in California. Of the 1332 observations, 1215 were viscosity values, including 786 of gas-free crude oil, 351 of oil saturated with gas, and 78 under-saturated with gas at pressures above the bubble point. Results show that crude oil viscosity at various reservoir conditions can be predicted with average deviations varying from 24.2 per cent for gas-free crude oil to as little as 2.7 per cent for undersaturated crude oil "above the bubble point." The solubility of crude oil may be predicted from oil gravity and saturation pressure with an average deviation of 22.0 per cent from observed values. In conclusion, it is shown that the viscosity of a gas and gas-saturated crude oil may be predicted within the accuracy of most reservoir computations. Viscosity is a measure of flow resistance; common units are in centipoises (cp.). The object of this report is to present conversion charts and simplified 'correlation charts showing the viscosity behavior of air, water, gas and crude oil and gas-saturated crude oil under oil field temperatures and pressures, which have been known to be as high as 300°F. and 8000 Ib. per sq. in. gauge under subsurface conditions. The viscosity of a liquid or gas is important because it is a measure of its fluidity, or its ability to flow through pipe lines or oil sands. Viscosity of air has become important because it is being used in secondaryl,2 recovery projects. The viscosity of natural gas and water at reservoir conditions is useful because they are almost universally associated and produced with crude oil. The viscosity of gas-saturated crude oil at reservoir pressures and tem peratures is of particular value in making estimates of oil reserves3 and rate of oil recovery from flush pools when production decline data are limited. Instruments Used to MeasuRe Viscosity There are many types of viscosimeters,4 and the instruments most commonly used to measure the atmospheric viscosity of liquids at moderate temperatures and their practical working ranges have been deScribed5,6 in detail. Fig. I and Fig. 2 are viscosity conversion charts which have

Jan 1, 1946

By Thomas A. Read

THE internal friction of single crystals of metals is affected markedly by a variety of factors, which, according to the literature, are without influence on the internal friction of polycrystalline metals at strain amplitudes less than 10-5. For example, the internal friction of a suitably oriented zinc single crystal is multiplied by a factor of l00 when the vibration amplitude is slightly increased, and the internal friction of a copper crystal is markedly increased by the application of a stress of 30 lb. per sq. in. for one minute. In this paper it will be shown that these, together with the other phenomena associated with the damping of mechanical vibrations in metal single crystals, can be satisfactorily explained, at least qualitatively, in terms of an atomic mechanism that has been proposed for quite another purpose-that of accounting for slip in metals. The extraordinary agreement between the observed behavior of the metal single crystals and the behavior that could be predicted on the basis of this atomic mechanism leads to the belief that the latter is probably essentially correct. If this is so, it follows that valuable information about the slip process in metals may be gained from measurements of internal friction on single crystals. In this paper the results of the only study to date on the damping of mechanical vibrations in single crystals of metals will be presented. EXPERIMENTAL PROCEDURE The internal friction of a material is a measure of the rate at which the energy of mechanical vibrations is converted into heat. The measure of internal friction used in the present paper is the decrement A, which is defined as the fraction of the energy of vibration lost per half cycle. The measurements described here were .made for longitudinal oscillations at a frequency of 33.5 kc. for the copper crystals, and at a frequency of 39 kc. for the zinc crystals. The method used is that of the composite piezoelectric oscillator. The single-crystal specimens are in the form of circular cylinders ¼ in. in diameter and 1 ½ to 2 ½ in. long. The crystal rods are waxed in a V-block and sawed to the proper length with a fine jeweler's saw. The ends of the specimen are ground flat, and one end is cemented with a very thin film of beeswax and rosin to the end of an x-cut quartz rod which is ¼ in. in diameter and 3 in. long. The length of the specimen rod is determined by the condition that its natural frequency for longitudinal vibration be the same as that of the quartz rod, within 0.5 per cent. The lengths of the specimens are thus different for different orientations of the cylinder axis with respect to the crystallographic axes. When the specimen and quartz rods are thus matched in frequency the adhesive is at a node of stress, and it has been shown experimentally that under these circumstances

Jan 1, 1941

By E. H. Lancaster, M. E. Mitchell

A MUD-conditioning program found to be very effective for drilling and completion operations on routine field wells requiring relatively short drilling time involves a moderate alkaline-tannate-bentonite treatment resulting in an ultimate filtration rate of 10.0 cc or less (API test). Mud weight schedules are planned from pressure information on completed wells in producing reservoirs and drill-stem test data obtained on other zones not being produced at present. In general, terminal mud viscosities average 45 sec (Marsh). This value has been found to be sufficient to remove cuttings from the well bore on the average well, with the slush pumps in general use on the rigs. On field wells requiring drilling times in excess of approximately 30 days, an alkaline-tannate-lime-bentonite treatment has been effective in maintaining desirable viscosities and filtration rates with a substantial reduction in chemical costs. This system has shown particular advantage on heavily weighted muds and those with abnormal flow-line temperatures. For the most part, the chemical treatment utilized in wildcat drilling follows closely the program used on field wells, depending on depth and duration of drilling operations. Wildcat mud programs are planned from information available from various geologic and operational sources, taking into consideration the possibility of encountering mud problems of a special nature in the wildcat area. Careful planning of wildcat mud pro- grams has proved to have definite value in avoiding most serious mud problems. An analysis and recommended treatment are presented on several special. mud problems which have been encountered in the area in the past. Those problems discussed are lost circulation, blowouts, sloughing shale, excessive chloride contamination, sulphate contamination, and prevention and correction of cement contamination. Introduction Drilling-mud control in the Southwest Texas area, in general, does not involve the multiplicity of problems encountered in other coastal areas. For instance, it is rare that a mixture of problems such as lost circulation, abnormal pressure, severe sloughing shale, and others, occurs on one well within close enough limits in vertical depth not to be taken care of by a sensible casing program, together with a relatively clear-cut mud program. There are conditions such as the fairly widespread occurrence of abnormal pressure in the lower Frio and Vicksburg zones, and the tendency for sloughing shale in the Jackson section which make for rather expensive mud control. However, the availability of fairly accurate geologic and operational information makes possible a reasonable degree of standardization on mud treatment over a relatively large area. It may be said that, over most of this area where drilling is currently in progress, the natural mud made is very poor in quality, but responds readily to moderate chemical treatment to yield very good wall-building characteristics. AS far as field development drilling is concerned, the mud engineer's principal job, once the routine treatment best

Jan 1, 1949

By M. E. Wadsworth, R. C. Peterson, W. M. Fassell

The temperature and pressure dependence of the reaction of tantalum in oxygen were investigated from 500° to 1000°C at pressures from 10 mm Hg to 600 psi total oxygen pressure. Tantalum was found to oxidize linearly under the above conditions. Three distinct regions of temperature dependence were found with different energies of activation. From 500° to 600°C the rate of oxidation of tantalum was found to be essentially independent of the oxygen pressure at the pressure investigated. The oxidation rate increases rapidly with an increase in pressure from 600' to 800°C. The dependence of the oxidation rate on the bulk concentration may be expressed by V = k'?, where k' is the specific rate constant and ?=k1Co2/(l + K1Co2), where k, is the equilibrium constant for the adsorption of oxygen on tantalum. ONLY a limited amount of data has been presented in the literature on the oxidation behavior of tantalum metal. Some values of its oxidation rate were reported in the Corroston Handbook' and by McAdams and Geil.' The first extensive investigation of tantalum was the work of Gulbransen and Andrews." They determined the reaction rates of tantalum in O2 and N2. Their results indicate that this metal follows the parabolic law in the temperature range of 250" to 450°C in O2 at pressures of 7.6 cm Hg with an activation energy of 27,400 cal per mol. In nitrogen, the metal follows the parabolic law from 500" to 800°C at 7.6 cm pressure. All experimental determinations were of 2 hr or less duration and deviations from the parabolic rate conceivably could occur at longer times. A spectrophotometric study of the oxidation of tantalum by Waber, Sturdy, Wise, and Tipton' indicated good agreement between this method and the microbalance technique. The experiments were conducted in air from 220" to 350°C. The metal was found to follow the logarithmic law up to 320°C and the parabolic law at higher temperatures. The activation energies in the logarithmic region were reported as 12.57 kcal per mol and 12.0 kcal per mol, respectively, for the microgravimetric and spectrophotometric methods. In the parabolic region the activation energy was found to be 27.2 kcal per mol, in good agreement with the value of Gulbransen and Andrews." The present paper is concerned with the behavior of tantalum from 500" to 1000°C in oxygen at pressures ranging from 1/2 to 40.8 atm pressure. Earlier preliminary data by McKewan5,6 indicated the following facts concerning the behavior of tantalum: 1—At temperatures from 500" to 600°C, the metal followed the linear law. 2—At 575°C the rate of oxidation was found to increase with O2 pressure. 3—The Arrhenius plot in this temperature region was nonlinear. The nonlinearity of the Arrhenius plot was indicative of a more complex behavior than originally suspected for this metal.

Jan 1, 1955

By Robert E. Green

Formulae are given for calculating the modes of wave propagation in a single-crystdl specimen possessing a given crystallographic orientation. Such calculations lead to determination of the orientation factor appearing in the Granato-Lucke theory for the attenuation of these waves due to dislocation damping. A detailed treatment is given for the case of an aluminum crystal possessing the orientation having a maximum Schmid fac -tor of 0.5. FOR a number of years the attenuation of ultrasonic waves propagating in metals has been used to investigate various phenomena causing internal friction.Most of the experiments were performed on polycrystalline test specimens and the waves were assumed to be propagating in an isotopic medium. However Alers 6 in 1955 and more recently Hikata et at. Chiao and Gordon,8 and Swanson and Green 10 have used measurements of attenuation of ultrasonic waves to study internal-friction changes in single crystals. These authors were concerned with the energy losses experienced by the ultrasonic waves due to dislocation motion induced by plastic deformation of the crystals. Alers measured the attenuation of 7 mc per sec ultrasonic pulses propagating in zinc single crystals before, during, and after plastic deformation. Simultaneously he measured the time-dependent plastic strain at constant stress in order to study the correlation between this strain and attenuation. The crystals were oriented in such a way that the applied stress provided a direct shear on the slip plane, thus causing the deformation to proceed by slip on this plane. At the same time the high-frequency sound pulses were sent through the crystal perpendicular to the slip plane. He found that the attenuation of transverse waves, the stress vectors of which lie in the slip plane, was very sensitive to the deformation. The polarization of the particle displacements, associated with these waves, relative to the applied static shear stress, and hence the direction of slip, had no obvious effect on the results. The attenuation of longitudinal waves was affected by the deformation only when the slip plane was not perpendicular to the propagation direction. This indicated that the attenuation was caused by dislocations introduced by the deformation and moving only in the slip plane. Hikata et al. made simultaneous measurements of attenuation, velocity changes, and stress-strain relations on aluminum single crystals deformed in tension. Both longitudinal and shear waves were used, at frequencies of 10 and 13 mc per sec. They placed emphasis on the choice of propagation modes and polarization of the ultrasonic waves, such that interactions between these waves and dislocations on selected slip systems could be investigated. They also selected specimens possessing specific crys-tallographic orientations, which allowed investigation as a function of the number of equally favored slip systems under the applied stress. They found that, for symmetrical orientations, the change of attenuation decreases with the increasing number of equally favored slip systems, i.e., in the order

Jan 1, 1964

By A. F. Bertuzzi, M. R. Tek, F. H. Poettmann

A method is presented for predicting pressure drop for two-phase fluid flow in horizontal pipes. A set of 267 experimental measurements randomly sampled from approximately 1,000 measurements from various literature sources was used. Pressure gradients calculated by the procedure developed and compared with the experimental values showed a bias of +0.82 per cent and a standard deviation of 20.8 per cent. The advantatges of this method over other available methods of predicting two-phase flow pressure drop are (a) its comparative simplicity of application, (b) its relative independence of flow patterns, (c) its accuracy, which on the basis of a statistical evaluation predicts pressure drop closer than other available methods, and, (d) its ability to satisfactorily correlate laboratory data from various sources while the correlations from these sources do not appear to agree with one another. The method has been reduced to a simplified graphical procedure, suitable for field use. A two-phase f factor is defined and correlated with parameters involving the flowing gas-liquid mass ratio, a Reynolds number for the gas phase, and a Reynolds number for the liquid phase. The choice of parameters allows the correlation to reduce to the usual f factor plot for the limiting conditions of (111 gas or all liquid. INTRODUCTION The mechanics and characteristics of two-phase flow systems have been of interest throughout the industry for some time. In numerous engineering installations such as pipe lines, chemical reactors, and heat exchangers, two-phase flow conditions are of every day occurrence. In oil production operations it has been desirable, in some cases, to consider transporting gas and oil together in a common pipe from oil field to process plant. The trend toward centrally located stock tank batteries in oil fields has resulted in longer gathering pipelines in which more than one fluid phase is flowing. The increase in the producing capacity of oil wells due to new production tech- niques has created the need for review and re-design of many surface gathering lines for properly handling the increased production. Optimum pipe size for the situations described above has become an important factor. The problem which is of interest here involves the ability to predict the relationship between pressure drop, fluid properties, fluid rates, pipe diameter, and pipe length. Although the literature1,5,10,13,18,19 contains various articles dealing with specific cases of the problem, Lock-hart and Martinelli17 proposed the most general solution. Their method has been later modified by Baker:1 Alves2 demonstrated that different flow patterns are possible for a flow mechanism defined by Martinelli such as gas turbulent, liquid turbulent. Baker explained deviations experienced with Martinelli's correlations on the basis that different flow patterns could exist for the same flow mechanism. Using Martinelli's method of correlatioil, Baker correlated data for each flow pattern for the turbulent-turbulent flow mechanism. Bergelin and Gazley6,7 presented a correlation for predicting gas phase

Jan 1, 1957

By J. L. Lamon, W. Crafts

Study with the electron microscope of the carbides in vanadium-chromium-molybdenum steels after tempering up to 1000 hr at 600 teelsto 1400°F confirmed that alloy carbides are formed at the secondary hardening temperature by decomposition of the plate-like iron carbides. It was also demonstrated that vanadium carbide persists as much smaller particles than do chromium- or molybdenum-bearing carbides. Conditions conducive to the formation of fine vanadium carbides are indicated to be favorable for high temperature strength. IN order to determine the effects of long exposure at high temperatures on vanadium-bearing steels, a survey has been made of their hardness and carbide structure. The behavior of carbides in the tempering of martensite was studied by X ray diffraction and electron microscope examination of electrolytically extracted residues in greater detail than in an earlier investigation.' A group of steels with about 0.25 pct carbon and containing chromium up to 5 pct, molybdenum up to 1 pct, and vanadium up to 1 pct was either quenched or annealed and then tempered for peri- ods of up to 1000 hr at 600° to 1400°F. Their hardness after tempering agreed with the Hollomon and Jaffe2 relation of equivalency of time and temperature, and with the degree of secondary hardening predicted from composition. Further, the appearance of the carbides indicated that the time and temperature equivalency relation was also applicable to the degree of carbide development. The mechanism of the tempering of martensite was demonstrated more clearly than in the earlier study. It was confirmed that carbides develop from martensite as poorly defined plates of the Fe2C type carbide followed by thickening of the plates with a transition to Fe,C. Finally the plate structure deteriorates into a lacy mass from which alloy carbides emerge as chunky particles that grow slowly with further increase of tempering temperature. Vanadium carbide derived from tempered martensite was found in characteristically small particles that tended to grow very slowly. The addition of chromium or molybdenum to a steel with predominant vanadium carbide tended to introduce carbides of a chromium- or molybdenum-bearing type having a somewhat larger particle size. The Cr,C, type carbide particles were larger than those of the V,C, type and somewhat smaller than the carbides in steel containing both Cr,C and M,C. Similar observations were made of the carbides in the pear lite of annealed steels. It appeared that high temperature properties would be benefited by the retention of the fine carbide particles that result from a balance of composition and heat-treatment designed to produce a maximum amount of vanadium carbide. Procedure: The steels used in the investigation were made with a base of Armco iron in a high-frequency furnace at the Union Carbide and Carbon Research Labs., Inc. The steels were deoxidized

Jan 1, 1951

By A. W. H. Morris, E. A. Steigerwald

The jatzgue beizazriov oj Mietal matrix co))zpos~tes in tension -lensiom loading has been imestigated as a junction of Dolume fraclion veinfovcelnent using the model systems of a silver matrix reinforced with contlnuous or dzscontztinuous aligned tungsten jilamenls and continuous aligned steel filamenls. Appreciable impvocetnents in fatigue strength were obseved in all syslems inzvesLigated, the degree of sl renglhenng-increasing with increasing volume fraclion of reinforcement. The mode of fatigue failure was found to be a function of colutrre jp-actiotz and was also noted to be controlled by the relative fatigue and strength characlerislics of the matrix and reinforcemenl. THE advantages to be gained by suitably incorporating high-strength filaments or whiskers into metallic matrices are well-recognized.' To date emphasis has been placed on the experimental determination of tensile strengths and elastic moduli of metal matrix composites measured parallel to unidirectionally aligned filaments. Several attempts have been made to relate experimentally measured tensile properties to theoretical values calculated from the properties of the components on the basis of the relatively simple "rule of mixtures" analysis. However, relatively few data have been reported in the literature on the fatigue behavior and mechanism of fatigue failure of metal matrix composites. In a study of fatigue crack propagation in aluminum plus steel wires and aluminum plus tungsten wires, Forsyth et a1.2 found that the incorporation of small numbers of filaments suitably dispersed were capable of substantially reducing the rate of fatigue crack propagation. For this purpose, the strength of the filaments appeared to be more important than the aspect ratio and the authors reported that parallel filaments were not the most favorable orientation for increased strength. In a basic study of the fiber reinforcement of metals, Williams and 0'brien3 report preliminary results which indicate a considerable improvement in fatigue strength in reversed bending fatigue of a steel wire-reinforced aluminum alloy composite. In a study of the influence of interfacial bonding on fatigue behavior, Baker4 has also reported improved fatigue properties in stainless steel-reinforced aluminum composites. In contrast, Ham and place5 report that, although tensile properties are improved greatly by filament reinforcement, the reinforcement of copper with continuous, brittle tungsten wires up to 23 vol pct was comparatively ineffective against fatigue. The authors attribute the poor fatigue properties of the composite to fatigue hardening of the matrix at the tips of cracks which can build up stress concentrations sufficiently large to fracture proximate filaments. Baker and cratchley6 failed to find marked improvements in the reversed-bending fatigue properties of silica-reinforced aluminum. The study was complicated by the complex behavior in a composite during the compres-sive half-cycles imposed in this type of loading. This was manifested in the failure of the composites by de-lamination, a contributing factor being the presence of aluminum oxide at the matrix-filament interface. Prior to the general acceptance of filament-rein-

Jan 1, 1968