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By A. E. Harnsberger

I is obvious that details such as the physical and chemical properties and methods of heat-treating of the materials mentioned must be omitted in a paper on the subject of materials used in oil-refinery pumps1. Only sufficient identification is given to enable the reader to find additional information from already published data. Also, the subject covers many operating conditions, but only the most important services can be discussed here. To the oil refiner, the pumping equipment is of vital interest. Practically every refinery operation, from the charging of crude oil to a distillation unit to the shipping of refined products, involves some form of pumping machinery. Intermediate refining stages involve a great variety of pumping machinery to carry out successfully the aims of the refinery technologist. Temperatures at which oils are handled vary from — 50" F. to 900" F. Pressure may vary from subatmospheric to 2000 1b. per sq. inch. The selection of the proper materials involves a careful consideration of the conditions under which the particular pump must operate. The four most important considerations are temperature, pressure, corrosion, and abrasion or wear. Consideration of temperature may be divided into three parts: (1) extremely low temperatures of the order of —50" F.; (2) temperatures at atmospheric or slightly above; (3) temperatures from 200" to 900" F. Pressures fall into two groups: (1) pressures reached by ordinary trade pumps of the order of 200 lb. per sq. in., (2) extreme pressure conditions involving pressures as high as 2000 lb. Noncorrosive and corrosive oils can be treated differently. Under the latter falls corrosion in the presence of water, which will occur up to 250" F. The second type of corrosion occurs in high-temperature pumping equipment, with temperatures from 450" to 900" F., largely caused by sulfur compounds. There are also other corrosive conditions met with in refinery operations, particularly in the handling of acids, acid sludges and other specialized processes. These problems, although difficult to

Jan 1, 1935

By Bertrand S. Summers

The technologist who has devoted much attention to the foundry-business will perhaps have noticed that the present scientific development of foundry-practice is in a condition similar to that of the steel-business some twenty years ago. In many cases chemistry is looked upon with suspicion, and the old cutand-try-methods are still in vogue, especially in the smaller foundries. The larger works have laboratories and more extensive means for applying science, and have devoted considerable time and attention to the improvement of foundry-practice. This is more especially true in the East, although in the West there are numerous firms devoting considerable attention to improving their metllods through the application of chemistry to work in the iron-foundry. It is hardly necessary to dwell extensively upon the effects of the different metalloids associated with iron, in pig- or castiron, in the way they are given in most text-books. The writer has thought proper to consider more particularly new developments in eupola-practice, particularly those pertinent to the discussion of the physics of cast-iron. In this connection some new ideas which recent practice has developed will be mentioned, and some results of practical tests along the same line will be described. Yet it has been deemed advisable also, by way of introduction, to outline the effects of the metalloids as they are described in most text-books, without going into detail. The question is sometimes asked, What is the most important element governing the quality of cast-iron 'for any particular purpose ? It would seem that right here lies the basis for the greatest difference of opinion. Some twenty years or more ago, silicon was regarded by foundrymen as one of their worst

Jan 1, 1899

By Irwin Roman, Thomas C. Serman

It has been known for many years that when a wire is moved in a magnetic field, an electromotive force is developed which is proportional to the rate at which the wire is moved in a direction perpendicular to the magnetic intensity and to the magnetic intensity itself. If the ends of the wire are connected to a current indicator, the current behaves exactly as though the source of electromotive force were a galvanic cell. If a wire is wound circularly and rotated uniformly around a diameter not parallel to the intensity, the current flowing through the wire will be alternating of sinusoidal shape. If, instead of a single loop, there are several turns wound in a short helix, the electromotive force developed will be approximately proportional to the number of turns, the area of the helix and to the speed of rotation. The maximum electromotive force will be developed when the axis of rotation is perpendicular to the field; if this is not so, only the component of the intensity that is perpendicular to the axis of rotation is effective. This is the principle of the usual earth inductor. With a few turns of wire and comparatively slow rotation, it is possible to produce a considerable deflection of a galvanometer. If two similar coils are rotated together at two different points for which the magnetic field intensities perpendicular to the axes of rotation are different, the electromotive forces developed will each depend on its corresponding intensity and be a measure of that intensity. If the intensities are sufficiently different so that the electromotive forces may be compared, the two intensities may be compared. This is the principle

Jan 1, 1934

By Francis Collins, E. R. Brownscombe

A study has been made of the material balance-fluid flow method of estimating reserves and degree of water drive from pressure and production history data. By considering the effect of random pressure errors it is shown that in a particular example a standard deviation of three and one-half pounds in each of ten pressure survey? permits the determination of the reserves with a standard deviation of 8 per cent and the water drive with a standard deviation of 15 per cent, assuming that certain basic geologic data are correct. It is believed that this method of estimating reserves and water drive is useful and reliable in a number of cases. The method is particularly valuable when reservoir pressure data are accurate within a very few pounds, but may also be applied with less accurate pressure data if a relatively large reservoir pressure decline occurs early in the life of the field, as for example in an under-saturated oil field. INTRODUCTION A knowledge of the magnitude of reserves and degree of water drive present in any newly discovered petroleum reservoir is necessary to early application of proper production practices. A number of investigators have contributed to methods of relating reserves, degree of water drive, and production and pressure history. 1-8 Three types of problems of increasing complexity may be mentioned. If a reservoir is known to have no water drive. and if the ratio of the volume of the reservoir occupied by gas to the volume of the reservoir occupied by oil (which ratio permits fixing the overall compressibility of the reservoir) is known, then only one further extensive reservoir property remains to be determined, namely the magnitude of the reserves. A straightforward application of material balance considerations will permit this determination. The problem becomes very much more difficult if we wish to determine not only the magnitude of the reserves but also the magnitude of water drive, if any, which is present. In principle, a combination of material balance and fluid flow considerations will permit this evaluation. Finally, if neither the magnitude of reserves, the degree of water drive, nor the ratio of oil to gas present in the reservoir is known and it is desired to determine all three of these variables, the problem could in principle be solved by a fluid flow-material balance analysis which determines the overall compressibility of the reservoir at various points in its history. The change in compressibility with pressure would provide a means of determining the ratio of gas to liquid present, since the compressibilities of gas and liquid vary differently with pressure variation. However, in practice this problem is probably so difficult as to defy solution in terms of basic data precision apt to be available.' It is the purpose of this discussion to illustrate the second case, which involves the determination of two unknown variables, single phase reserves and degree of water drive, from pressure and production history and fluid property data, and to study the precision with which these unknowns can be determined in this manner in a particular case. Although an electric analyzer developed by Bruce as used in making the calculations to be described, numerical methods necessary in carrying out the process have been devised and have been applied for this purpose. Schilthuis,' for example, developed a comprehensive equation for the material balance in a reservoir. He combined this with a simplified water drive equation, assuming that the ratio of free gas to oil was fixed by geological data and that a period of constant pressure operation at constant rate of production was available to determine the constant for his water drive equation. On this basis he was able to compute the reserves and predict the future pressure history of the reservoir. Hurst developed a generalized equation permitting the calculation of the water drive by unsteady state expansion from a finite aquifer. He showed in a specific case how the water influx calculated by his equation, using basic geologic and reservoir data to fix the constants, matched the water influx required by material balance considerations. Old3 illustrated the simultaneous use of Schilthuis' material balance equation and Hurst's fluid flow equation for the determination of the magnitude of reserves and a water drive parameter from pressure and production history. He used this method to calculate the future pressure history of the reservoir under assumed operating conditions. As a basis for determining reserves, Old assumed a value for his water drive parameter and calculated a set of values for the reserves, using the initial reservoir pressure and each successive measured pressure. The sum of the absolute values of the deviations of the resulting reserve numbers from their mean value was taken as a criterion of the closeness of fit to the experimental data possible with the water drive parameter assumed. New values of the water drive parameter were then assumed and new sets of the reserves calculated until a set of reserves numbers having a minimum deviation from the average was established. The average value of- the re-

Jan 1, 1949

By E. R. Brownscombe, Francis Collins

A study has been made of the material balance-fluid flow method of estimating reserves and degree of water drive from pressure and production history data. By considering the effect of random pressure errors it is shown that in a particular example a standard deviation of three and one-half pounds in each of ten pressure survey? permits the determination of the reserves with a standard deviation of 8 per cent and the water drive with a standard deviation of 15 per cent, assuming that certain basic geologic data are correct. It is believed that this method of estimating reserves and water drive is useful and reliable in a number of cases. The method is particularly valuable when reservoir pressure data are accurate within a very few pounds, but may also be applied with less accurate pressure data if a relatively large reservoir pressure decline occurs early in the life of the field, as for example in an under-saturated oil field. INTRODUCTION A knowledge of the magnitude of reserves and degree of water drive present in any newly discovered petroleum reservoir is necessary to early application of proper production practices. A number of investigators have contributed to methods of relating reserves, degree of water drive, and production and pressure history. 1-8 Three types of problems of increasing complexity may be mentioned. If a reservoir is known to have no water drive. and if the ratio of the volume of the reservoir occupied by gas to the volume of the reservoir occupied by oil (which ratio permits fixing the overall compressibility of the reservoir) is known, then only one further extensive reservoir property remains to be determined, namely the magnitude of the reserves. A straightforward application of material balance considerations will permit this determination. The problem becomes very much more difficult if we wish to determine not only the magnitude of the reserves but also the magnitude of water drive, if any, which is present. In principle, a combination of material balance and fluid flow considerations will permit this evaluation. Finally, if neither the magnitude of reserves, the degree of water drive, nor the ratio of oil to gas present in the reservoir is known and it is desired to determine all three of these variables, the problem could in principle be solved by a fluid flow-material balance analysis which determines the overall compressibility of the reservoir at various points in its history. The change in compressibility with pressure would provide a means of determining the ratio of gas to liquid present, since the compressibilities of gas and liquid vary differently with pressure variation. However, in practice this problem is probably so difficult as to defy solution in terms of basic data precision apt to be available.' It is the purpose of this discussion to illustrate the second case, which involves the determination of two unknown variables, single phase reserves and degree of water drive, from pressure and production history and fluid property data, and to study the precision with which these unknowns can be determined in this manner in a particular case. Although an electric analyzer developed by Bruce as used in making the calculations to be described, numerical methods necessary in carrying out the process have been devised and have been applied for this purpose. Schilthuis,' for example, developed a comprehensive equation for the material balance in a reservoir. He combined this with a simplified water drive equation, assuming that the ratio of free gas to oil was fixed by geological data and that a period of constant pressure operation at constant rate of production was available to determine the constant for his water drive equation. On this basis he was able to compute the reserves and predict the future pressure history of the reservoir. Hurst developed a generalized equation permitting the calculation of the water drive by unsteady state expansion from a finite aquifer. He showed in a specific case how the water influx calculated by his equation, using basic geologic and reservoir data to fix the constants, matched the water influx required by material balance considerations. Old3 illustrated the simultaneous use of Schilthuis' material balance equation and Hurst's fluid flow equation for the determination of the magnitude of reserves and a water drive parameter from pressure and production history. He used this method to calculate the future pressure history of the reservoir under assumed operating conditions. As a basis for determining reserves, Old assumed a value for his water drive parameter and calculated a set of values for the reserves, using the initial reservoir pressure and each successive measured pressure. The sum of the absolute values of the deviations of the resulting reserve numbers from their mean value was taken as a criterion of the closeness of fit to the experimental data possible with the water drive parameter assumed. New values of the water drive parameter were then assumed and new sets of the reserves calculated until a set of reserves numbers having a minimum deviation from the average was established. The average value of- the re-

Jan 1, 1949

By D. O. Hobson

Zirconium single crystals of various specific orientations were fabricated by rolling or drawing. The resulting textures were determined and are discussed with respect to the deformation modes that produced them. The crystals deformed in a predictable manner by combinations of up to third-order twinning with three twinning modes and by slip. Twinning was found to play a major role in initial texture formation. Texture changes produced by slip occurred only at the higher reductions. The twinning sequences that produced each intensity peak during the initial reductions could be identified. Schmid factor criteria were found useful in predicting which deformation modes to expect for each crystal orientation and fabrication procedure. The possible application of these data to poly-crystalline material is discussed. PREFERRED orientation or texture has a significant effect on the properties of most materials, causing anisotropy in fabricated cubic metals and enhancing the natural anisotropy of noncubic metals. This study evaluates the effects of several fabrication methods on the textures formed from specific starting orientations of zirconium single crystals and, it is hoped, gives an insight into the effects of the same operations on poly-crystalline material. BACKGROUND In fcc and bcc metals, texture changes take place by gradual lattice rotations caused by the operation of one or more slip systems. Deformation twinning plays an insignificant role in the deformation of such metals. In zirconium and its alloys, however, and in many other hep metals the ability to twin allows very rapid texture changes to be made with very small amounts of deformation. The deformation systems found in zirconium and its alloys are prism slip and three twinning modes.1 Slip occurs on the {1010}< 1120) system. There is little or no appreciable basal slip in zirconium. The twinning planes, illustrated in Fig. 1, are {1012}, {ll2l}, and {1122}. Two twinning modes, the {1012} and the {ll2l} operate for a tensile stress along the basal pole. A compressive stress parallel to the basal pole is required for {ll22} twinning. These twinning operations cause a 35- to 85-deg reorientation of the basal pole. The {1012} twin is the predominant tensile twin at room temperature. The twinning shears, S, are shown in the figure. A criterion for predicting which deformation system will operate when a grain is subjected to a known stress state is the Schmid (orientation) factor. This factor gives the fraction of the applied stress that computer program was written2 to calculate the Schmid factors for the four deformation modes in zirconium. It assumed three orthogonal stress axes and considered ninety-one different orientations of the basal pole in one octant of this stress space. At each basal pole position the Schmid factors were calculated for seven positions of rotation at 10-deg increments of the unit cell about the basal pole. Schmid factors were determined for a total of 637 orientations and for twenty-four deformation systems in each orientation. The program listed the Schmid factors for uniaxial stress parallel to each axis and, to approximate rolling, or-thonormal biaxial stress was also considered. Fig. 2 shows the range of orientations over which the various types of deformation would tend to predominate in biaxial plane strain with the stresses, equal magnitude. The exact boundary position between regions of different deformation modes depends, however, on the relative values of the critical shear stress for each deformation mode. Fig. 2 is drawn on the assumption that they are equal and it therefore may be only approximately correct. It is also recognized that the biaxial stress analysis may not be applicable in certain crystal orientations. EXPERIMENTAL PROCEDURE Single crystals of zone-refined zirconium, produced by Wilson of this Laboratory,3 were electrical-discharge-machined to form specimens for rolling, tube-drawing, and rod-drawing studies. Specimens were rolled at room temperature on 2-|--in.-diam hand-powered rolls from three different starting orientations: 1) the basal plane parallel to the rolling plane and the [1120] in the rolling direction, (0001)[ll20]; 2) the (1120) plane parallel to the rolling plane and the basal pole in the rolling direction, (1120)[0001]; and 3)_the (1120) plane parallel to the rolling plane and the [1100] in the rolling direction, (1120)[ll00]. Drawing specimens were cut with the [0001] direction as the drawing direction in the tube blank and [1120] as the drawing direction in the rod specimen. The drawing

Jan 1, 1969

Jan 1, 1916

By J. J. Egan, A. B. Kinzel

Much work has been done recently in an attempt to analyze the physicochemical mechanism involved in the production of steel by the open-hearth process. This has resulted in reducing the process to a series of interrelated phenomena obeying the usual laws of mass action and diffusion. Of these, the reaction of the iron oxide and carbon in the molten steel is of most interest from a technical point of view as it constitutes the main action in the usual steelmaking processes. A. L. Feild&apos; has formulated a basic differential equation expressing the open-hearth reactions and Herty has done considerable experimental work on the determination of a number of constants involved in the basic open-hearth reaction. In considering the application of the law of mass action to the reaction FeO + C + CO + Fe, the iron will be taken as constant, as is the case in the open hearth and the carbon monoxide pressure will be assumed constant at one atmosphere. From this xy = m at equilibrium, where x is the percentage weight of carbon, y percentage weight of iron oxide and m the weight-concentration equilibrium constant. While it is customary for physical chemists to express equilibrium constants in terms of molar concentrations, the constant is here expressed as the product of the percentage-weight concentrations for ease of comparison with the constants quoted by Herty and by Beild, and for more ready applicability to the open-hearth reactions. Herty and his associates have attempted to calculate the value of this constant from data on open-hearth heats. So many variables affect these results that an adequate calculation presents very great difficulties. A value of 4 X lop2 was first arrived at, but this was later changed to 1.6 X 10-2. Feild, in order-to illustrate the operation of the differential equation of the open hearth, has assumed a value considerably lower than Herty&apos;s, namely, 1.0 X 10-2, the largest value consistent with certain theoretical

Jan 1, 1929

By A. S. Adams

A glance at the list of papers1 that have been published since 1920 on the general subject of flotation suggests the variety of ideas that exist regarding the underlying cause of the phenomenon. Among these ideas, we find several coherent theories, but none that adequately and completely explain the phenomenon. Ralston2 and Bains3 suggested an electrical theory which has to do with the attachment of mineral particles to a bubble by the attraction of unlike electrical charges. This theory has its root in the fact that a bubble of air in pure water is electrified in such a way that the surfacc is negatively charged while the body of the water is positively charged. This result, which was first discussed by Helmholtz, also obtains when the water contains anything except a high concentration of hydrogen ions, or ions which are trivalent or tetravalent. The theory also holds that the mineral particles have positive charges on their surfaces, and so there is attachment between bubble surface and mineral particles by the old law of electrostatics, which states that unlike charges attract. Contact Angle and Oil Attraction The contact angle—the angle formed by a fluid-fluid boundary when both are in contact with a solid-—has been indicted several times for complicity in the phenomenon of flotation. This angle is supposed to indirectly measure the surface energy of a solid. Thus if we have two fluids in contact with a solid, we may express the difference between the two fluid-solid tensions as equal to the fluid-fluid tension times the cosine of the angle between the two fluids.4 If the two fluids are in contact with the solid, this is, no doubt, an excellent way of establishing relative surface energies. However, in flotation, we deal with substances which are not wetted by water. What assurance have we, then, that the angle

Jan 1, 1928

By P. B. Liebermann

The resistance to motion offered by mine cars is caused principally by: Rolling friction, flange friction, bending rails, bearing friction and wind resistance. With proper construction and with a fair amount of attention and care, that is, under favorable conditions, the first three items cannot be greatly improved. The wind resistance ordinarily is negligible on account of the slow speeds commonly used. The bearing friction, however, is a variable item, depending upon the design, the bearing material, the lubrication, the location (whether in wheel-hub or on car-body) and the alignment. Under the most favorable conditions the bearing friction will reach a lowest possible value. By the development of a successful anti-friction mine-car bearing this lowest value has been improved to such an extent as to affect the whole system of mine haulage. After being satisfied of their durability and certainty of operation, any investigation into the advantages of anti-friction bearings for mine cars will have to be based upon reliable information as to the saving in power of such bearings. While numerous tests have been made in this direction, the results have not always been convincing, principally because of the rather crude methods that were employed. These crude methods are the main cause of the wide variations existing in regard to the exact amount of the frictional resistance. Frequently an ordinary spring balance is used and the pull necessary to move a certain car or train of cars is obtained by a number of readings. Such spring balances necessarily have a coarse graduation and the continuous vibration and fluctuations to which they are subjected make them highly dependent upon the individual observer. Further, they must be frequently calibrated. Sometimes these tests were made without regard to acceleration, speed or even grade. The method of using an electric locomotive as a testing device is perhaps more open to criticism than the spring-balance method, because it introduces additional sources of error: The varying electrical and mechanical losses in the locomotive. Also, such a measurement always includes the power necessary to move the locomotive itself. This means a considerable amount of figuring, and the results due to the various multiplications and corrections may be of little value, for obvious reasons. When figuring the drawbar pull from the electrical

Jan 1, 1917

By P. H. Brace

THE study of the relations between gases and metals is one of perennial interest to all who are connected with the production of high-grade metallurgical products. The data reported here are the outcome of work of which the object is to determine the effects of dissolved gases upon the properties of metals and to gain a more detailed knowledge of the reactions between gases and molten metals, particularly iron, under definitely controlled conditions. We have attempted to reduce our margin of error by dealing with relatively large quantities of metal, from 4 to 13 lb. (2 to 6 kg.), and keeping the ratio of refractories to metal as small as practicable. The ingots produced are large enough to provide adequate material for making determinations of magnetic and other physical properties. In choosing the bell-jar type of furnace we were influenced by the results of considerable experimentation along the same general line which indicated that, for the scale or which we were to work, it was important to have the furnace structure independent of the vacuum enclosure. The use of a bell-jar surrounding the entire furnace accomplishes this and also gives great freedom of observation during operation and ready accessibility for the replacements which are necessary after each run. Our choice of analytical method was made in the light of the results secured by H. M. Ryder, who used a method similar in principle for the analysis of very small quantities of gas extracted from strips of metal heated electrically in high vacuum. We have presented some selected preliminary experimental data as being illustrative of the quantity and nature of the gases which occur in iron of different origins, but do not urge any hypothesis at this time.

Jan 1, 1928

By G. S. Phipps, E. E. Schumacher, G. M. Bouton

THE seriousness of the present tin scarcity has stimulated large consumers of this vital metal to develop drastic conservation measures in order to extend the available supplies to cover the emergency period. By devising new soldering methods and alloys the Bell System has contributed a substantial share in the tin conservation effort, Fortunately, the changes, as far as can be determined now, have not introduced weakness into the soldered joints. Some of the new procedures were already in the process of development at the onset of the emergency, while others were devised under its stress. In some instances, the newly developed solders were found to be more difficult to use than the alloys previously available, and would not have been introduced under normal conditions. One major change made that previously had been under consideration will result in large savings of tin. Unless service difficulties are encountered, this modification gives promise of remaining after the emergency has passed. The change involves a reduction in the amount of solder placed on a wiped joint between the cable sheath and the sleeve. Instead of the customary full sized wiped joint, a wipe of fillet proportions is formed. Through this change, a solder saving of more than 60 per cent per joint can be realized. Plumbers and cable splicers for many years have joined lead pipes and cable sheath by a soldering process called "wiping." The name is an apt description of the operation. For a wiped joint, the sections to be united&apos; are heated by molten solder poured over their surfaces, and the resulting semiliquid mass is manipulated by wiping with cloth pads to a well rounded symmetrical form like the one shown in Fig. I, The operation requires considerable skill on the part of the splicer and close control of the composition of the solder. At first consideration, the problem of tightness in such joints seems simple but experience shows that even under the best conditions the fissures frequently found in the solder occasionally link and form a path that allows leakage to occur. In telephone cables not maintained under gas pressure, such leaks permit the entrance of water, which wets the paper-covered conductors and thereby impairs the insulation value and causes service interruptions. By going to an extreme and wiping off all the solder in excess. of a fillet, it has been found that many causes of porosity are eliminated. Figs. 2 and 3 show cross sections of joints wiped in the old and the new ways. The saving in solder, and consequently in strategic tin, is evident. The field splicing forces find that joints are easier to make by the new method and are less likely to be porous. The metallurgical considerations that are responsible for the success of the fillet wipe are of interest. Much has been written about the wiping process of soldering cable joints and the many requirements of a good wiping solder have frequently been listed. The success of the procedure described

Jan 1, 1943

By A. Dubé, G. Letendre, C. E. Beaulieu

An experimental study has been made of the time dependence of internal .friction and modulus of rigidity in- freshly quenched steels at room temperature. The effects of frequency, composition, and various thermal treatments are given. The kinetic 1aws observed cannot be fully explained by the so-called first stage of tempering and the transformation of retained austenite. It is suggested that the observed phenomena are due to the progressive immobilization of dislocations introduced by the martensitic transformation. It is generally agreed that the conversion of tetraginal martensite into cubic ferrite and ce-mentite occurs in three stages which at moderate rates of heating take place in the following temperature ranges:&apos;-3 a) The first stage involves mainly a partial loss of tetragonality of martensite and the formation of ?-carbide between 95" and 175oC. b) The second stage consists of the decomposition of retained austenite between 230 and 290&apos; C. c) The third stage covers the formation of ce-mentite between 290o and 400&apos; C. The kinetic laws of these heterogeneous reactions have also been the subject of isothermal studies. Thus, Roberts, Averbach. and cohen3 report a very low reaction rate with a eutectoid steel at room temperature. For example, less than 10 pet of the contraction associated with the first stage is observed after 50 hr at room temperature. Hollonlon, Jaffe, and Buffum4 show that under the same conditions less than 10 pet of the tetragonality is lost. These results have led to the belief that martensite is a relatively stable phase at room temperature. On the other hand, it is well known that important structural changes occur in martensitic steels during the first few minutes at room temperature after quenching. This pretempering has at least two important consequences. In the first place, freshly quenched steels have a tendency to crack at room temperature, a fact which leads to the necessity of tempering as soon as possible after the quench. Another important consequence of pretempering a steel for short periods of time at room temperature is the stabilization of the retained austenite. Thus, as shown by Cohen,5 a very pronounced stabilization is effected with holding periods of 30 min at room temperature. Since these two effects are apparently not caused by the heterogeneous reactions mentioned above, they must be related to the rearrangement of structural defects within the martensite and retained austenite. According to the modern theory of dislocations, the shears required to effect the austenite-marten-site transformation may be realized through the motion of dislocations at the austenite-martensite interface and within the martensite plates.6 In this way, a martensitic transformation closely resembles a plastic deformation. In cold-worked solids, high concentrations of dislocations are left immediately after the plastic deformation and it seems reasonable to assume that appreciable densities of dislocations should also appear in the wake of a martensitic transformation. A considerable part of the high hardness of martensite would then originate in the obstruction of dislocations in analogy

Jan 1, 1961

By Philip D. Wilson

The mines of the Calumet & Arizona Mining Co. are situated in the Warren Mining District, Cochise County, Arizona, between Bisbee and Warren and adjoin those of the Copper Queen Consolidated Mining Co. and the Shattuck Arizona Copper Co. Paleozoic 1imestones.of considerable thickness have been intruded by granite porphyry. A great stock of the intrusive outcrops boldly near the city of Bisbee and is known as Sacramento Hill. From this central core the porphyry has tongued out into the limestone for many thousands of feet as dikes and sills of irregular shape and variable dimensions. Churn drilling has recently developed a large tonnage of secondarily enriched copper ore in the main porphyry mass of Sacramento Hill. While some ore has been found in porphyry in other parts of the district, it is relatively unimportant compared with that which occurs in the Paleozoic limestone as irregular lenses replacing favorable beds near porphyry contacts or associated with well-marked fracture zones often many hundreds of feet away from the intrusive. In a zone extending from Sacramento Hill for a distance of from 1,500 to 3,000 ft., the limestone has been extensively metamorphosed and in this contact metamorphic zone the ore occurs through a known vertical thickness of upward of 900 ft. and individual orebodies often show extension in a vertical direction of over 200 ft. At a greater distance from the intrusive stock, the ore occurs as lenses of greater horizontal than vertical dimensions with an average thickness of approximately 30 ft. An exception to this rule is found in the occasional steeply dipping mineralized fractures, almost true tabular veins, which are found long distances a way from the zone of contact metamorphism. The copper was probably introduced during or slightly later than the porphyry intrusion in the form of chalcopyrite and bornite. These primary copper minerals are always associated with pyrite and often occur as rich lenses in a huge mass or shell of pyrite carrying an insignificant percentage of copper. In many instances the copper-bearing solutions were preceded by siliceous solutions and these latter, often persisting during the period of mineralization, have thoroughly indurated the ore-

Jan 1, 1917

By R. I. Jaffee, R. M. Evans

IN recent years, the interest in liquid metals as heat-transfer media for power plants has been very great. The possibility of the development of nuclear power plants has increased this interest and served as the impetus behind much research on low melting metals and alloys for such purposes. The principal reasons for consideration of liquid metals as heat-transfer media lie in their high thermal conductivity and consequent high heat-transfer coefficients, stability at high temperatures, and the high ranges of temperature possible. The element gallium possesses some of the requisite properties for a heat-transfer liquid. It is a unique material, having a low melting point and a high boiling point. Pure gallium melts at 29.78oC, and suitable alloying will produce a metal which melts below room temperature. The boiling point is about 2000°C. As it is a liquid metal, the heat-transfer characteristics would be good. Gallium is not now readily available, due in part to a lack of uses for the metal. Nevertheless, it is not a rare element, and a sufficient supply of gallium exists to permit its consideration for this use. Since gallium has some promise as a heat-transfer liquid, owing to its unique properties, research on the subject was carried on at Battelle Memorial Institute at the request of the Bureau of Ships, U.S.N. The research had as its objectives the determination of the effect of alloying on the melting point of gallium, and the study of the corrosion of possible container materials. In this research, alloys were found which had significantly lower melting points than pure gallium, but none which simultaneously fulfilled other additional requirements, chiefly the corrosion problem. Neither was it found possible to reduce the melting point of certain otherwise suitable alloys appreciably by small additions of gallium or gallium alloys. The results gave little hope that gallium alloys can be developed which enhance the good properties and minimize the undesirable characteristics of elemental gallium. Thus, gallium now appears less promising than other metallic heat-transfer media. The experimental thermal-analysis techniques used in this work have been described.&apos; Experimental Results As a first approximation, the development of low melting gallium alloys was based on alloying elements suitable for use in a nuclear power plant, which also lowered the melting point of gallium. Information from the literature, summarized in Table I, indicates that. tin, aluminum, and zinc are the only suitable elements which cause a lowering of the melting point of gallium. Indium and silver also lower the melting point of gallium, but are of little interest for use in nuclear power plants. Of the elements reported not to lower the melting point of gallium, there is some ambiguity on the behavior of copper. Weibke3 obtained solidus arrest temperatures of 29°C for Cu-Ga alloys from 60 to 90 pct Ga, 0.8C lower than the generally accepted melting point. This may be the effect of a eutectic close to gallium, or, more likely, the result of impurities, or experimental error. The seven elements listed in Table I whose effects were not known were of potential interest if they lowered the melting point of gallium. Their effects were determined experimentally for this reason. Binary alloys containing nominally 2 pct of each of these elements were prepared in the form of 2-g melts by placing the components in a graphite crucible and holding them in an argon atmosphere at 370°C for 5 hr. These melts were then subjected to thermal analysis. In all cases. the solidus temperature was the melting point of gallium. Since these elements (As, Ca, Ce, Mg. Sb, Si, and T1) did not lower the melting point of gallium, they were not considered further as components of a eutectic-type alloy. Ga-Sn-Zn Alloys Preliminary considerations of this system for low-melting alloys were encouraging. All three binary systems were of the simple eutectic type. The composition and melting points of the eutectics were as follows: Sn-9 pct Zn (199°C), Ga-8 pct Sn (20°C), and Ga-5 pct Zn (25°C). Therefore, the probability of a ternary eutectic was high. For reasons to be discussed later, aluminum could not be used as an alloying constituent, leaving the Ga-Sn-Zn system as the only one of interest for low-melting gallium-

Jan 1, 1953

By F. W. Gordon

The Whitwell firebrick hot-blast stove, for furnace use, may be seen in its three main stages of development in the accompnying drawings. Fig. 1 is the stove of 1869, the year in which it was thoroughly tested at the Consett furnaces, England; Fig. 2, the stove of 1876 and 1877, in which it was intended to reduce the cost by increasing the height; Fig. 3, the stove of 1880. Many modifications were made from time to time, generally in the direction of improvement, but the drawings illustrake the main features of progress. In the stove of 1869 the plan was to introduce the gas at A, and pass it up and down between each alternate wall, the air in the reverse direction, passing in at B. The friction in this stove was so great, owing to the restricted area of the passages and the many revervals of the gaseous current, that it was deemed imprudent to build the stoves higher than 28&apos; 6". Another reason mas that the great importance of cleaning was carefully kept in view, and it was very difficult to operate any hand scraper even to this depth. For these reasons the 22&apos; X 28½&apos; stove held the field for several yearn. A slight change made from this was to the 18&apos; X 40&apos; stove, where the height was increased, but the dumber of walls diminished. In this stove the friction was somewhat reduced, but so was the heating surface, and although it cost a little lea it was not any better. The next important change, seen in Fig. 2, was by increasing the height to GO feet and keeping the full number of walls in the stove. The heating surface and mass were much increased in proportion to the cost, and the friction decremed by alterllating over and under two or more walls, instead of one, as formerly. This stove gave admirable satisfactiou, but, although the proper doors were provided, it was very difticult to clean, owing to the long (distance the scrapers lid to traverse. Stove No. 3 is a modification of No. 2. The great question was how to decrease the cost mithotlt impairing in any yaw the

Jan 1, 1881

CHARGING of an open-hearth heat is begun as soon as possible after the previous heat has been tapped. Ordinarily, about 40 min. is required to drain and dress the furnace hearth, make up the tap hole, and perform routine repairs of the banks. Repairs to the upper back wall and to the front wall and jambs can ordinarily be done while the first scrap charge is being heated and are therefore allowed to wait in order to save furnace time. Any major repairs required on the hearth or other parts of the furnace necessitate longer delays, because such repairs must be made while the furnace is empty. Although charging practice varies considerably in detail with the type and proportions of scrap and iron used, many factors are common to all varieties of&apos; charge. Such general considerations are dealt with first. GENERAL CHARGING PRACTICE Charge materials are discussed in detail in Chapter IV; the present chapter is concerned with the charging, melting, and proportioning of the raw materials in the various types of furnace practice. Charging Equipment and Stock Handling. The physical equipment available for loading and weighing the stock, transporting it to the furnace, and charging it may have a major effect on charging practice. Limestone, scrap, and all other solid melting stock are charged mechanically by means of equipment described in Chapter I (see also Fig. 18, page 33). It is generally desirable to charge the scrap about as fast as the physical volume can be got into the furnace. A limiting factor may be the height to which the scrap may be piled in the furnace without deflecting the flame to such an extent that it will impinge on the roof or walls and thus damage the refractories, but light scrap may often be piled up near the roof since the flame usually "cuts it down" rapidly before impingement on any roof area can persist long enough to do appreciable harm. When the nature of the scrap and the handling facilities are adequate to meet the aim of rapid charging, little thought is given to this feature of operation. Unfortunately, at times

Jan 1, 1944

By Philip S. Morse

THE Australian lead-smelting plants began to use charges carrying high zinc percentages somewhat earlier than was common with American plants. When lead smelting first started in Australia the immense deposits of oxidized lead at Broken Hill were available but later these oxidized ores became exhausted and were replaced by sulfides. This was before the days of flotation and these sulfides when concentrated carried about 1 per cent. of zinc to 6 per cent. of lead. The works of the Sulphide Corpn. at Cockle Creek was perhaps the pioneer in high-zinc slags but the Port Pirie plant of the Proprietary Co. was a close and very able second and has continued the work to the present time. The Cockle Creek lead furnaces remained in operation until shortly after the war when most of the Broken Hill companies combined and took over the Port Pirie plant to treat their concentrates. As it was the practice both at Cockle Creek and Port Pirie to carry 20 per cent. or more of lead on the charge, it was found that under these conditions of large amounts of zinc in the charge, good roasting was absolutely necessary and matte production was unwise. The Hunting-ton-Heberlein system of roasting was introduced and later the Dwight & Lloyd process. In this way, by roasting the sulfide portions of the charge as thoroughly as possible and making no matte, a method of smelting was developed where the slag over long periods carried as high as 20 per cent. ZnO without serious furnace troubles, and slags carrying even up to 33 per cent. ZnO have been reported. The zinc slags were not very different in appearance from the ordinary slags produced in American practice except that they gave off more smoke and fume on tapping. The slag usually ran hot and freely, coming from the tap in a full stream. Normally there was little crust on the sides of the furnace and the tuyeres gave no trouble though they were always rather dark. At the works of the Sulphide Corpn. it was the custom, on account of the labor situation, to shut down the furnaces during the Christmas holidays, thus giving a campaign of about 12 months. The furnaces at the end of the run usually showed no crust on the sides, though crusts always occurred at the back and front ends. A furnace campaign of 22 to 23 months has been made at this plant where both sides of the

Jan 1, 1929

By Y. L. Yao

THE NaT1-type compound may be considered as the penetration of two diamond lattices in such a way that a superstructure of the bcc lattice is formed. Examples of the NaT1-type compound of lithium are LiZn, LiCd, LiA1, LiIn, and LiGa. Except for LiZn and LiCd, each molecule of these equiatomic compounds contains a total of four valence electrons. In LiZn and LiCd it was suspected (for example, see Ref. 1) that the fourth electron was withdrawn from the 18-shell of zinc or cadmium. An incomplete 18-shell would have to show strong paramagnetism. In 1955 Klemm and Fricke2 determined the magnetic susceptibility of LiZn, LiCd, LiA1, and LiIn (also NaTl and NaIn). The molar susceptibility of the outer electrons of LiZn and LiCd was found to be not strongly but weakly positive; that of LiAl and LiIn not negative but weakly positive. Thus they questioned the hypothesis about LiZn and LiCd in particular and the description of the NaT1-type structure in general. However, they did not determine the magnetic susceptibility of LiGa. This note is to report results for all five compounds of lithium. The starting materials are 99.9 pct pure lithium sticks containing less than 0.005 pct Na. 99.9 pct Zn, 99.9 pct Cd, 99.99 pct Al, 99.999 pct In, and 99.999 pct Ga. Weighed amounts of two components were wrapped in tantalum foil and placed in a graphite crucible. It was found that the tantalum sheath minimized the vaporization losses of lithium during melting. The sheath was easily stripped from the alloy rod and the tantalum in the alloy was barely detectable (less than 0.01 wt pct). The melting was performed in a resistance furnace under an argon atmosphere. Alloy specimens were annealed for 1 hr at 400°C in vacuum. The magnetic susceptibility at room temperature was determined by the Faraday Method, using the procedures previously described.&apos; The results are shown in Table I. The interpolated values at 50 at. pct of Li and the average values at 48 to 52 at. pct of Li at 20°C determined by Klemm and Fricke2 are also shown. It is seen that the present value for LiZn and LiCd is slightly more positive but the present value for LiAl and LiIn is slightly less positive than their corresponding values. Also, it is noted there is an abrupt decrease of susceptibility of LiAl from 51.2 to 52.5 at. pct of Li. Klemm and Fricke2 found that the total susceptibility of LiZn, LiCd, LiA1, and LiIn is almost independent of temperature. slater4 gave a working expression for the diamagnetism of the atomic core as follows:

Jan 1, 1964

By M. J. Marcinkowski, E. N. Hopkins

An investigation has been made of the ß(fcc) — a(hexagonal) transformation which occurs in lanthanum using both electrical resistivity and transmission electron microscopy techniques. It has been shown that the ß phase can be retained below the transformation temperature by rapid quenching but that the sample immediately begins to transform to the a phase. The transformation is observed to nucleate in the vicinity of inclusions. Based on the above observations, a detailed model of the transformation has been advanced which involves the nucleation of an extrinsic stacking fault bounded by a pair of Shockley partial dislocations in the vicinity of some heterogeneity, i.e., an inclusion. The stress field of the resultant dislocation pair acts to nucleate extrinsic faults in adjacent planes and leads quite naturally to the B-a conversion with a minimum of strain energy induced in the crystal. LANTHANUM possesses an fcc structure ß) (8) upon cooling transforms to a hexagonal modification (a) in much the same way as cobalt. The one exception, however, is that the stacking sequence of the closest packed planes in a La is ABAC ABAC, and so forth,1 whereas in cobalt it is ABAB, and so forth, i.e., hep. Mainly on the basis of transmission electron microscopy techniques, there seems to be little doubt that the 0 — a transformation in cobalt involves a dislocation mechanism2 although its exact nature still remains obscure. Although the ß - a transformation in lanthanum is somewhat more complex than that occurring in cobalt, it was thought that its very uniqueness would be helpful in understanding fcc — hexagonal transformations in general. Such a general understanding of these transformations is important since they represent what are perhaps the simplest of the martensitic class of transformations. The experimental techniques used were those of electrical resistivity and transmission electron microscopy. EXPERIMENTAL PROCEDURE The lanthanum used in this investigation was prepared by the calcium reduction of lanthanum fluoride in a tantalum crucible under an argon atmosphere as described by Spedding et al. The residual calcium was removed by vacuum remelting in a tantalum container. Portions of the metal were then analyzed by emission spectroscopy as well as vacuum fusion. The amounts of the various impurities that were found are listed in Table I. A portion of the lanthanum ingot was swaged at room temperature into 0.030-in.-diam rod for the resistivity samples while the remainder was rolled into 0.010-in.-thick sheet for the transmission electron microscopy phase of this investigation. In order to eliminate the plastic deformation induced in the samples during fabrication, they were sealed in evacuated tantalum lined quartz capsules and annealed for 1 hr at 700° C. Specimen resistances were measured using the conventional "four-wire" technique described by MacDonald, 4 employing a type K-3 Universal Potentiometer and a standard 0.001-ohm resistor, both manufactured by Leeds and Northrup Co. By taking into account all of the possible errors in the apparatus, it was felt that the absolute resistivities of the approximately 0.87-in.-long specimens measured are reliable to 3 pct. Resistances from room temperature to 700°C were measured using a vacuum furnace. In order to avoid sample contamination by the thermocouple, chromel-alumel leads were spot-welded into a tantalum shield which in turn was welded to the lanthanum specimen. Resistances below room temperature were obtained by transferring the sample to a helium gas-filled quench tube and slowly dripping liquid nitrogen into a surrounding dewar flask. A steady reduction of temperature to about —190°C was completed in about 23 hr, and the resistances were measured at various temperature intervals. As will be shown shortly, rapid quenching from above about 350°C was sufficient to suppress the B -a transformation initially but subsequent annealing at lower temperatures leads to a partial ß --a conversion. To investigate this aspect of the transformation, the samples were suspended in the hot zone of a helium-filled furnace from which they could be rapidly dropped into the quench tube mentioned previously which was now

Jan 1, 1969