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By E. A. Nichols

The purpose of this paper is to present a contour map that shows the geographical variation in geothermal gradients in the Mid-Continent and Gulf Coast oil fields. Introduction Frequently there arises the need for an estimation of the temperature to be expected at a predetermined depth in working with a wildcat or in deepening old production into 'Ones that are relatively unknown. The study of geothermal gradients in oil fields has been made previously by many investigators. One of the pioneers in this work was C. E. Van Orstrand,' who, as well as most of the other investigators, was primarily interested in the relation between temperature and depth in a given locality. Between 192r and 1929, American Petroleum Institute Research Project NO. 25 fostered a thorough study of earth temperatures.2 K. IV. French did some work in California, the results of which were published in 1939.3 In most of these studies, an attempt was made to correlate temperatures in a rather localized area. This paper will show the results of an attempt to correlate temperature gradients over rather large Portions of the Mid-Continent and Gulf Coast area. Method of Obtaining Data It has been found that for complete thermal equilibrium to be established in a well, the well must stand undisturbed for a period of several hours to several weeks, depending upon the way the well was produced prior to the shut-in period. The data in this paper were obtained in conjunction with running pressures in wells or in taking samples of reservoir fluid. Glass maximum recording thermometers were used in all but a few instances. The wells had been shut in from one hour up to I. or 12 days. Since the wells were normal producing wells, some of the shut-in times undoubtedly were insufficient for complete thermal equilibrium to have been established and the temperatures measured do not necessarily represent the true earth temperatures. They do represent the temperature conditions that will be encountered in a well that is producing oil. The data, therefore, can be useful in working with or in estimating the temperatures to be expected in producing reservoirs. In obtaining a thermal gradient by dividing the difference in temperature of the formation and the mean annual surface temperature by the depth of the formation, one is assuming the depth-temperature line to be straight. Depth-temperature curves are almost straight lines (Fig. I). However, on close examination of accurate data, a slight curvature usually is observed. Most wells yield curves with slopes increasing with increasing depth. These curves are believed to be from wells that are in and are underlain by sedimentary material. Some few curves have slopes that decrease with increasing depth. These curves are believed to be from wells that are underlain rather closely by granite or some other igneous rock. Most investigators

Jan 1, 1947

By Nathaniel Arbiter

T. M. Morris (School of Mines and Metallurgy, Rolla, Mo.)—Rate studies promise to help quantify flotation operations. The author's exposition of rate studies is therefore laudable. However his exposition of a second order rate equation rather than a first order rate equation is not convincing. It is important to use the correct equation, otherwise erroneous conclusions may be drawn. The data assembled by the author and plotted according to a second order rate equation can be plotted according to a first order rate equation. As a matter of fact much of the data used reveals that a second order rate equation is not applicable. According to the method used by the author for plotting data, the reciprocal of the slope of the line is the maximum possible recovery. Physically this cannot exceed 100 pct, yet several graphs yield maximum recoveries greater than 100 pct. For example: l—Curve 2, Fig. 1 yields a value of 120 pct; 2—Curve 2, Fig. 2 yields a value of 115 pct; 3—Fig. 7 yields a value of 110 pct. The real test of the graphical method is, as the author points out, whether or not the earliest points agree with a straight line. The second order rate plot does not fulfill this requirement. Fig. 10 shows the data used by the author to obtain Curve 2 in Fig. 1, plotted according to both a second and first order rate equation. Fig. 11 shows the two rate plots made from data published by Ludt and DeWitt.19 In Fig. 10 the first order rate plot gives a very good fit and obeys the boundary condition of passing through the origin. For the second order rate plot a straight line can be drawn through the last three points but the earliest points are not in agreement with this line. The reciprocal of the slope of the straight line gives a value of maximum possible recovery of 112 pct. The maximum possible recovery according to the first order rate plot is 78 pct. In Fig. 11 the first order rate plot again fits all of the points very well and passes through the origin. The second order rate plot shows wide deviation of the earliest point, indicating that the second order rate equation is not applicable. The reason for the fit of data to the second order rate equation during longer flotation times is that R, the cumulative percent recovery, changes slowly toward the end of the flotation operation, so that when t/R is plotted against time, one is, in effect plotting t against t and one would certainly expect a straight line. The author attempts to show that the second order rate equation is correct by citing evidence which shows that recovery is a function of initial concentration. This is a debatable point especially since, in the author's original presentation of this paper at the St. Louis

Jan 1, 1952

By A. H. Geisler, R. F. Mehl, C. S. Barrett

The complicated nature of the property changes that accompany age-hardening has made it necessary to reconsider and to elaborate the simple dispersion theory.l It has been apparent for some time that more direct information is needed concerning the atomic mechanism of precipitation from solid solution if the theory of age-hardening is to be developed past a purely qualitative stage.‡ Fortunately, in recent years information has been developed which allows us to trace in detail the lattice changes accompanying the process of precipitation from solid solution. This information relates chiefly to the sequence of the several stages of lattice alteration by which the matrix lattice is transformed to the equilibrium precipitate lattice, and permits reasonable inferences to he drawn concerning the states of internal strain that accompany these stages. This information is most complete for the solid solution of copper in aluminum. The equilibrium precipitate is the 0 phase, "CuAl2." This forms in plates, parallel to the {100} matrix planes. The atom pattern and atom spacing on the plane in 0 lying parallel to this plane are roughly similar to those opposite it in the matrix.3 The formation of 0, however, is preceded by the formation of a transition lattice 0': which again lies parallel to the matrix {100} plane, but in this case the matching of atom pattern and spacing across the matrix-precipitate interface is nearly periect; thus there is lattice coherency across the interface and the interface is a plane of separation in only a very limited sense.'8 Particles of 0' may be recognized microscopically and form a well-defined Wid-manstatten figure.* The 0' lattice is recognized by the occurrence of diffraction lines on powder photo-grams or of spots on Laue photograms which may be analyzed in the usual ways to determine the lattice type and the lattice spacings. Very recent research 6, 7, 1 has shown, however, that streaks occur on the Laue photogram at an earlier point in time during the aging process. These streaks have been attributed to a preferential clustering of copper atoms into small platelike elements of only a few atoms in thickness and a lew hundred atoms in diameter, probably of the composition of " CuA12," which may be designated as Guinier-Preston zones or aggregates.1 It is difficult if not impossible to determine the lattice type and lattice spacing in these aggregates. It is possible1 that these aggregates are in fact ?' in a high State of dispersion; the inclination to argue this is strong, as we shall see later. Never-

Jan 1, 1941

By R. F. Mehl, C. S. Barrett, A. H. Geisler

The complicated nature of the property changes that accompany age-hardening has made it necessary to reconsider and to elaborate the simple dispersion theory.l It has been apparent for some time that more direct information is needed concerning the atomic mechanism of precipitation from solid solution if the theory of age-hardening is to be developed past a purely qualitative stage.‡ Fortunately, in recent years information has been developed which allows us to trace in detail the lattice changes accompanying the process of precipitation from solid solution. This information relates chiefly to the sequence of the several stages of lattice alteration by which the matrix lattice is transformed to the equilibrium precipitate lattice, and permits reasonable inferences to he drawn concerning the states of internal strain that accompany these stages. This information is most complete for the solid solution of copper in aluminum. The equilibrium precipitate is the 0 phase, "CuAl2." This forms in plates, parallel to the {100} matrix planes. The atom pattern and atom spacing on the plane in 0 lying parallel to this plane are roughly similar to those opposite it in the matrix.3 The formation of 0, however, is preceded by the formation of a transition lattice 0': which again lies parallel to the matrix {100} plane, but in this case the matching of atom pattern and spacing across the matrix-precipitate interface is nearly periect; thus there is lattice coherency across the interface and the interface is a plane of separation in only a very limited sense.'8 Particles of 0' may be recognized microscopically and form a well-defined Wid-manstatten figure.* The 0' lattice is recognized by the occurrence of diffraction lines on powder photo-grams or of spots on Laue photograms which may be analyzed in the usual ways to determine the lattice type and the lattice spacings. Very recent research 6, 7, 1 has shown, however, that streaks occur on the Laue photogram at an earlier point in time during the aging process. These streaks have been attributed to a preferential clustering of copper atoms into small platelike elements of only a few atoms in thickness and a lew hundred atoms in diameter, probably of the composition of " CuA12," which may be designated as Guinier-Preston zones or aggregates.1 It is difficult if not impossible to determine the lattice type and lattice spacing in these aggregates. It is possible1 that these aggregates are in fact ?' in a high State of dispersion; the inclination to argue this is strong, as we shall see later. Never-

Jan 1, 1941

By H. S. Kalish, F. J. Dunkerley

Introduction and Previous Work THE determination of the low temperature tensile properties of tin and tin-lead alloys was initiated as part of an extensive research program on the phasial equilibria of tin binary systems below 13.2°C and the property changes associated therewith. A survey of the literature revealed that, although some room temperature tensile data were available for tin and a few tin-lead alloys, there existed no survey report of the low tcmPerature tensile properties of these alloys. Accordingly, the tensile data for tin and a series of pure tin alloys containing from 0.01 to 50 pet lead were measured at eleven temperatures horn — 196 to +20°C and are presented here in survey form. In addition to the importance of these tensile data as a preliminary to certain fundamental research, this information promises also to be of commercial importance because of the extensive use now being made of tin-lead solders in refrigeration and gas liquefaction equipment. Occasional failures of the solders in low temperature service have been attributed by some metallurgists to low temperature embrittlement, while others hold that failure results from the transformation of the tin-rich phase of the solder from the solid white (beta) to the powdered gray (alpha) form. From the data previously available in the literature, neither of these explanations can be completely corroborated. cohen and van Lieshout have estab-lished the beta to alpha tin transformation at 13,2°C and have shown that strain accelerates the transformation. Further, they showed that although I pct lead retarded the transformation, it was not eliminated. It will be pertinent, then, to note whether the beta to alpha transformation of the tin.rich phase will occur in a short-time tensile 'test. polanyi and schmid2 studied the tensile properties of tin single crystals at — 185°~ and report that tin is britlle at this tem-perature. In 1946, Kostenets3 reported that pure tin was brittle at —Ig6 and — 253°~, while lead remained ductile at both these temperatures. He also studied the tensile properties of tin-lead alloys containing from 10 to 75 pet lead at —253, —196 and + I~OC. The ultimate tensile strength increased more than two times in going from room temperature to — I96°C and about three times that value on further cooling to — 253 C- All the alloys were brittle at — 196'C except those containing more than 75 pct lead. Even at — 253'C, the 75 pct lead alloy retained 36 pet elongation in a 30 mm-ga. length. Creep is also an important phenomenon

Jan 1, 1949

By S. R. B. Cooke, S. W. Clark

Adsorption of calcium and magnesium by quartz was determined over a wide pH range using flame photometry for solution analysis. A parallelism was noted between calcium adsorption at alkaline pH and flotation of activated quartz by means of various fatty acid collectors. Abstraction of calcium from 100 ppm solutions increased above pH 10.5 until all of the calcium was removed at pH values between 12 and 12.5. Calcium was desorbed from the quartz over the pH range 12.5 to 13.0 and returned to the solution. Precipitation of magnesium hydroxide prevented measurement of magnesium adsorption above a pH of 9.9. A calcium adsorption isotherm determined at pH 9 matched measurements of barium adsorption by other investigators over the range where adsorption corresponded to the equation of a Freundlich adsorption isotherm. In accordance with the Gouy-Chapman theory for adsorption in the diffuse layer, adsorption of the divalent cations under these conditions was four times the adsorption of monovalent sodium. Activation of quartz by multivalent metal cations in flotation using anionic collectors has been studied by many investigators. The occurrence of activator cations in the water of flotation mills makes depression of silaceous gangue very difficult. Alternatively, in some flotation systems it is practical to cause activation of quartz so that it is floated from the desirable mineral values. The present study was initiated to investigate the activation of quartz by measuring adsorption of calcium and magnesium ions as a function of solution pH. Early empirical tests showed that quartz would be activated to flotation using anionic collectors if any of a number of divalent or trivalent metallic cations were present in the pulp.1*2 Subsequent studies by Clemmer,3 Cooke and Digre,4 Cooke,5 Schuhmann and Prakash,6 and Cooke, Iwasaki, and Choi,7-8 showed that flotation depended strongly upon the alkalinity of the flotation pulp, the concentration of the activating cations, and the chain length and structure of the organic collectors used. The concept of the electrical double layer has been applied to the case of the quartz-aqueous solution interface by Gaudin and Fuerstenau,9-10 and by de Bruyn 11 to explain the activation of quartz by multivalent metal cations. Studies of the surface of quartz by Gaudin and Fuerstenau9,10,12 and by Li " using the streaming potential technique contributed much information on the electro kinetic condition of the surface of quartz in the presence of various organic and inorganic ions. Measurement of adsorption of ac-

Jan 1, 1969

By Enid C. Plante, K. L. Sutherland

Practical metallurgists are unanimous in stating that oxidation of mined sulphide ore adversely affects separation of the constituent minerals under standard conditions in a mill. Frequently, the need for different operating conditions in different plants is attributed either to the extent of oxidation of the mineral surfaces or to soluble oxidation products. The investigations reported in this paper study the effect of oxidation on the primary condition necessary for flotation, namely that of adhesion of an air bubble to the mineral. Oxidation Products from Sulphide Minerals Weinig and Carpenter1 state that the relative rates of oxidation of some sulphides are: FeAsS > FeS2 > CuFeS2 > ZnS > pbS > Cu2S tetrahedrite. They also show that oxidation is rapid at first, that sulphides of older geological formations are more stable than those of recent date and that mixtures oxidize more rapidly than any one mineral alone. The more rapid oxidation of mixtures is borne out by results of Gottschalk and Buehler2 who found that PbS, zns and cus oxidized 8 to 20 times faster when pyrite was present. Only the end products of oxidation, sulphate and the metal ion, were identified in these tests. Gaudin3 states that pyrite is difficult to oxidize in the laboratory. Winchell,4 using pyrite containing 99.98 pct FeS2, allowed water to percolate through a bed of this ground material. At the end of three months only a trace of Fe+++and So4- were found. Even after 10 months the quantity of Fe+++ was only 7.8 mg and SO4- 25.5 mg per liter of percolating solution. Car-michael5 confirmed Winchell's results on the slow oxidation of pyrite. Usually the oxidation of sulphide surfaces has been conducted in neutral or acid solutions, the acidity being caused by the oxidation products. Eliseev and Nagir-nyaka found that treatment of pure pyrite with lime gave only thiosulphate, but considered it possible that thiosulphate was obtained not by oxidation of the pyrite itself, but by oxidation of calcium disul-hide. Mitrofanov7 suggested that thiO~ulphate was formed by the following process: oxidation of sulphide to give free sulphur (this frequently happens with marcasite), followed by oxidation of the sulphur to sulphur dioxide and reaction of the sulphur dioxide with sulphur to give thiosulphate. Ferric and ferrous hydroxides, or similar compounds, were shown to be present. The Research Staff of the United Verde Copper Co.8 treated ore from the United verde mine with lime. Thiosulphate, sulphide and polysulphides were stated to be

Jan 1, 1949

By Enid C. Plante, K. L. Sutherland

PRACTICAL metallurgists are unanimous in stating that oxidation of mined sulphide ore adversely affects separation of the constituent minerals under standard conditions in a mill. Frequently, the need for different operating conditions in different plants is attributed either to the extent of oxidation of the mineral surfaces or to soluble oxidation products. The investigations reported in this paper study the effect of oxidation on the primary condition necessary for flotation, namely that of adhesion of an air bubble to the mineral. OXIDATION PRODUCTS FROM SULPHIDE MINERALS Weinig and Carpenter1 state that the relative rates of oxidation of some sulphides are: FeAsS > FeS2 > CuFeS2 > ZnS >PbS > Cu2S tetrahedrite. They also show that oxidation is rapid at first, that sulphides of older geological formations are more stable than those of recent date and that mixtures oxidize more rapidly than any one mineral alone. The more rapid oxidation of mixtures is borne out by results of Gottschalk and Buehler2 who found that PbS, ZnS and CuS oxidized 8 to 20 times faster when pyrite was present. Only the end products of oxidation, sulphate and the metal ion, were identified in these tests. Gaudin3 states that pyrite is difficult to oxidize in the laboratory. Winchell,4 using pyrite containing 99.98 pct FeS2, allowed water to percolate through a bed of this ground material. At the end of three months only a trace of Fe +++and S04- were found. Even after 10 months the quantity of Fe+++ was only 7.8 mg and S04- 25.5 mg per liter of percolating solution. Carmichael5 confirmed Winchell's results on the slow oxidation of pyrite. Usually the oxidation of sulphide surfaces has been conducted in neutral or acid solutions, the acidity being caused by the oxidation products. Eliseev and Nagirnyak6 found that treatment of pure pyrite with lime gave only thiosulphate, but considered it possible that thiosulphate was obtained not by oxidation of the pyrite itself, but by oxidation of calcium disulphide. Mitrofanov7 suggested that thiosulphate was formed by the following process: oxidation of sulphide to give free sulphur (this frequently happens with marcasite), followed by oxidation of the sulphur to sulphur dioxide and reaction of the sulphur dioxide with sulphur to give thiosulphate. Ferric and ferrous hydroxides, or similar compounds, were shown to be present. The Research Staff of the United Verde Copper Co.8 treated ore from the United Verde mine with lime. Thiosulphate, sulphide and polysulphides were stated to be

Jan 1, 1947

By H. C. Burghard, F. R. Brotzen

Experiments were performed to determine the effects of mechanical vibrations on ordering in CuAu. The effects of 5, 10, and 15 kc vibrations were investigated over a range of ordering temperatures of 280° to 360°C. A decrease in the rate of ordering was observed at all frequencies and ordering temperatures. THE effects of mechanical vibrations on certain solid-state reactions have been noted by several investigators. In 1930, Mahoux' reported a substantial increase in the case depth of a steel sample nitrided under the influence of mechanical vibrations over that of an unvibrated sample. Similarly, an accelerating effect of vibrations on the diffusion of chromium in steel was noted. Guillet, in the same year, confirmed the results of Mahoux. More recently Schenck and schmidtmann3 studied the effects of low-frequency, alternating loads on the diffusion of carbon in steel. The results of their experiments, conducted at 500 cycles per min and large strain, (0.2 pct), indicated an acceleration of the process. These workers also reported an increase in case depth of a sample vibrated at 430 kc during a carburizing treatment. Effects of high-frequency vibrations on solid-state reactions have also been investigated by Gudzoff and Gavze6 and Fairbanks and Dewez.7 The former reported an acceleration of the age-hardening process in aluminum alloys. The latter noted changes in the structure and mechanical properties of steel annealed under the influence of vibrations. On the other hand, Altenburg4 and Ehringer5 have given some theoretical reasons and experimental evidence as to the improbability of any effect of vibrations on diffusion. Comprehensive surveys of the effects of vibrations on metallurgical reactions are given by Hiedemann' and Bergmann.9 None of the above investigations led to a physical description of the effects of mechanical vibrations on solid-state reactions. In the present study an attempt was made to gain an understanding of the influence of vibrations on nucleation and diffusion. The order-disorder transformation was chosen for investigation since its mechanism has been extensively discussed in the literature. Moreover, the progress of the transformation may be easily followed by observation of electrical resistance changes. EXPERIMENTAL PROCEDURE The specimens used for the experimental observation of ordering rates were prepared from 50 at. pct Cu-Au alloy wire.* Each specimen consisted of a 0.02-in. diam wire approximately 10 in. long to which two copper potential leads were silver soldered, 2 1/2 in. apart, near one end of the wire. A 1/8-in. diam by 1/4-in. long steel stub was silver soldered

Jan 1, 1960

By Maurice C. Fetzer, Charles R. Austin

It has long been known that plain high-carbon steels may be susceptible to graphiti-zation below the A1 critical, but no data have been available to indicate what factors cause and tend to inhibit graphite formation. Two recent publicationsl,2 have shown that the factors controlling graphitization below the A1 are different from those operating above the A1 inversion where commercial graphitization of malleable iron begins. Furthermore, for plain high-carbon steels graphitization below the critical point does not appear to be related to ordinary chemical analyses. Many years ago it was recorded3 that the rate of graphitization at subeutectoid temperature is not a maximum just below the A1 critical, but at some lower temperature, which Austin and Norris have shown to be about 670°C. Indeed, work done in our laboratory has demonstrated that it is impossible to spheroidize certain steels in the temperature range of 650° to 710°C. without the formation of considerable amounts of graphite. However, if the temperature is maintained just below the A1 (720°C.) these same steels may be completely sphe-roidized at constant temperature. In previous studiesl,2,4 on I per cent plain carbon steels graphitization was encountered during prolonged tempering. The limited number of steels studied did not provide sufficiellt data to permit adequate study of the factors controlling this graphitization. Accordingly, a limited statistical investigation was undertaken, utilizing 18 steels of similar chemical analyses, furnished by four steel companies, who also supplied information regarding the history of manufacture. An extensive program of research is being carried out on these steels, including the effect of pretreatment and atmosphere on the nature and extent of graphitization, and the possible correlation of graphitization with such characteristic properties as hardenability, grain size and mechanical behavior. In the present paper discussion is restricted to a study of the correlation between graphitizing tendency at 670°C. after quenching from several temperatures above the critical, and (I) the minor variations in the chemistry of these steels of "similar" chemical composition, and (2) the deoxida-tion practice employed. The state of the lead bath, oxidized or protected from oxidation by charcoal, used in the tempering treatments is also considered. Materials Eighteen plain carbon steels of about I per cent carbon, and containing similar amounts of each of the other common elements usually found as impurities, were obtained in the form of rods % in, in diameter from four steel manufacturers. The analyses for ordinary and special elements of all the steels were made on the rod stock as received in the laboratory, and the re-

Jan 1, 1941

By Maurice C. Fetzer, Charles R. Austin

It has long been known that plain high-carbon steels may be susceptible to graphiti-zation below the A1 critical, but no data have been available to indicate what factors cause and tend to inhibit graphite formation. Two recent publicationsl,2 have shown that the factors controlling graphitization below the A1 are different from those operating above the A1 inversion where commercial graphitization of malleable iron begins. Furthermore, for plain high-carbon steels graphitization below the critical point does not appear to be related to ordinary chemical analyses. Many years ago it was recorded3 that the rate of graphitization at subeutectoid temperature is not a maximum just below the A1 critical, but at some lower temperature, which Austin and Norris have shown to be about 670°C. Indeed, work done in our laboratory has demonstrated that it is impossible to spheroidize certain steels in the temperature range of 650° to 710°C. without the formation of considerable amounts of graphite. However, if the temperature is maintained just below the A1 (720°C.) these same steels may be completely sphe-roidized at constant temperature. In previous studiesl,2,4 on I per cent plain carbon steels graphitization was encountered during prolonged tempering. The limited number of steels studied did not provide sufficiellt data to permit adequate study of the factors controlling this graphitization. Accordingly, a limited statistical investigation was undertaken, utilizing 18 steels of similar chemical analyses, furnished by four steel companies, who also supplied information regarding the history of manufacture. An extensive program of research is being carried out on these steels, including the effect of pretreatment and atmosphere on the nature and extent of graphitization, and the possible correlation of graphitization with such characteristic properties as hardenability, grain size and mechanical behavior. In the present paper discussion is restricted to a study of the correlation between graphitizing tendency at 670°C. after quenching from several temperatures above the critical, and (I) the minor variations in the chemistry of these steels of "similar" chemical composition, and (2) the deoxida-tion practice employed. The state of the lead bath, oxidized or protected from oxidation by charcoal, used in the tempering treatments is also considered. Materials Eighteen plain carbon steels of about I per cent carbon, and containing similar amounts of each of the other common elements usually found as impurities, were obtained in the form of rods % in, in diameter from four steel manufacturers. The analyses for ordinary and special elements of all the steels were made on the rod stock as received in the laboratory, and the re-

Jan 1, 1941

By John Wulff, Robert Kamm, Steinberg Morris

In powder metallurgy it has often been observed that shrinkage may occur in one direction and growth in another during sintering. Even in long-time sintering experiments the rate of shrinkage may be different in different parts of the compact. In the fabrication of some parts requiring a constant permeability it is even questionable in some cases whether pressing from one direction should be attempted. These observations require for their interpretation a more detailed study of green or pressed density than has heretofore been available. Usually average density measurements of the whole compact are made and in some cases carefully cut sections are measured. A different approach to the problem was first mentioned by Rakowskil and also used by Balshin.2 Balshin's diagram is reproduced in Fig I and schematically shows the result of pressing three layers of metal powder with fine intervening layers of graphite. The retarding effect of the die walls and a qualitative example of the density distribution is evident. More quantitative information about the distribution of density within a cold-pressed powder compact would be useful in showing the variation in density in as as influenced by the type of poKder, shape of die, lubricatioll during the process, and other variables. Furthermore, information about the cracking of cold-pressed compacts may be obtained from an analysis of the stress distribution within a, powder compact, and some information about the stress distribution can be obtained in turn from the derlsity and strain distributions. A more detailed report on some of the present experiments appears in reference 3. Present Investigation In order to ascertain the density gradients in cold-pressed metal powders, a deformable lead grid within the powder was employed. After pressing in cylindrical di" the ejected compact was radiographed, giving a pattern of the deformed grid. From the radiograph density and deformation from point to point is readily measured. From the radiograph strain distribution and stress trajectories were also determined. The latter also permits the determination of the coefficient of friction at the die wall. This technique indicates that the densest Part of a compact pressed from one side is at the top outer circumference and the least dense region at the bottom circumfercnce near the stationary plunger. For Some heights of compacts the density at the axis is such that the lower density is at the top rather than at the bottom. SO irregular a density distribution is due primarily to die-wall friction. As the ratio - diameter to height of compact is increased the die walls play a correspondingly smaller role. More uniform density

Jan 1, 1947

By John Wulff, Steinberg Morris, Robert Kamm

In powder metallurgy it has often been observed that shrinkage may occur in one direction and growth in another during sintering. Even in long-time sintering experiments the rate of shrinkage may be different in different parts of the compact. In the fabrication of some parts requiring a constant permeability it is even questionable in some cases whether pressing from one direction should be attempted. These observations require for their interpretation a more detailed study of green or pressed density than has heretofore been available. Usually average density measurements of the whole compact are made and in some cases carefully cut sections are measured. A different approach to the problem was first mentioned by Rakowskil and also used by Balshin.2 Balshin's diagram is reproduced in Fig I and schematically shows the result of pressing three layers of metal powder with fine intervening layers of graphite. The retarding effect of the die walls and a qualitative example of the density distribution is evident. More quantitative information about the distribution of density within a cold-pressed powder compact would be useful in showing the variation in density in as as influenced by the type of poKder, shape of die, lubricatioll during the process, and other variables. Furthermore, information about the cracking of cold-pressed compacts may be obtained from an analysis of the stress distribution within a, powder compact, and some information about the stress distribution can be obtained in turn from the derlsity and strain distributions. A more detailed report on some of the present experiments appears in reference 3. Present Investigation In order to ascertain the density gradients in cold-pressed metal powders, a deformable lead grid within the powder was employed. After pressing in cylindrical di" the ejected compact was radiographed, giving a pattern of the deformed grid. From the radiograph density and deformation from point to point is readily measured. From the radiograph strain distribution and stress trajectories were also determined. The latter also permits the determination of the coefficient of friction at the die wall. This technique indicates that the densest Part of a compact pressed from one side is at the top outer circumference and the least dense region at the bottom circumfercnce near the stationary plunger. For Some heights of compacts the density at the axis is such that the lower density is at the top rather than at the bottom. SO irregular a density distribution is due primarily to die-wall friction. As the ratio - diameter to height of compact is increased the die walls play a correspondingly smaller role. More uniform density

Jan 1, 1947

By Morris Steinberg, John Wulff, Robert Kamm

IN powder metallurgy it has often been observed that shrinkage may occur in one direction and growth in another during sintering. Even in long-time sintering experiments the rate of shrinkage may be different in different parts of the compact. In the fabrication of some parts requiring a constant permeability it is even questionable in some cases whether pressing from one direction should be attempted. These observations require for their interpretation a more detailed study of green or pressed density than has heretofore been available. Usually average density measurements of the whole compact are made and in some cases carefully cut sections are measured. A different approach to the problem was first mentioned by Rakowski1 and also used by Balshin.2 Balshin's diagram is reproduced in Fig r and schematically shows the result of pressing three layers of metal powder with fine intervening layers of graphite. The retarding effect of the die walls and a qualitative example of the density distribution is evident. More quantitative information about the distribution of density within a cold-pressed powder compact would be useful in showing the variation in density in compacts as influenced by the type of powder, shape of die, lubrication during the process, and other variables. Furthermore, information about the cracking of cold-pressed compacts may be obtained from an analysis of the stress distribution within a powder compact, and some information about the stress distribution can be obtained in turn from the density and strain distributions. A more detailed report on some of the present experiments appears in reference 3. PRESENT INVESTIGATION In order to ascertain the density gradients in cold-pressed metal powders, a deformable lead grid within the powder was employed. After pressing in cylindrical dies the ejected compact was radiographed, giving a pattern of the deformed grid. From the radiograph density and deformation from point to point is readily measured. From the radiograph strain distribution and stress trajectories were also determined. The latter also permits the determination of the coefficient of friction at the die wall. This technique indicates that the densest part of a compact pressed from one side is at the top outer circumference and the least dense region at the bottom circumference near the stationary plunger. For some heights of compacts the density at the axis is such that the lower density is at the top rather than at the bottom. So irregular a density distribution is due primarily to die-wall friction. As the ratio of diameter to height of compact is increased the die walls play a correspond¬ingly smaller role. More uniform density

Jan 1, 1947

By M. Cohen, W. J. Harris

The recent application of lineal analysislt2 to the austenite-martensite reaction has made possible a quantitative study of the kinetics of this transformation during rapid cooling. Martensite range curves can thus be constructed to portray the onset of the reaction at Ma and its subsequent progress as a function of temperature down to and below the ambient. It now seems in order to investigate other aspects of the martensite transformation, using this quantitative method of approach. One of the least understood characteristics of the austenite-martensite reaction is that of stabilization which has been defined by Troiano and Greninger3 as 'la lowering of Ma, resulting from aging, without change in chemical composition of the parent solid solution." In other words, if the hardening quench is arrested at a predetermined subcritical temperature (TA) for a sufficient period of time, more austenite may be retained at a given lower Or reference temperature (Tr) than if the steel had been cooled directly and rapidly to Tr in the first place. For the purposes of the work at hand, the extent of stabilization produced by the isothermal treatment at Th is measured explicitly in terms of the excess austenite (6) that exists in the steel at T,, over and above the amount that is normally present after direct quenching to T,. T, is conveniently taken to be room temperature, but this choice is not essential and is sometimes undesirable. The holding temperature (TA) may be above or below M,, and still cause stabilization depending upon the themistry of the austenite. stabilization has been found to occur in the presence of bainite4 and of martensite6,6,7,8 as well as in the absence of either,g The phe-nomenon of stabilization is not concerned with (and may even be obscured by) ferrite formation or any other type of phase change occurring at T~ that alters the chemistry of the remaining austenite. Such a structural change would obviously influence the martensite transformation during subscquent cooling. Stabilization, however, is more subtle; it appears to manifest itself without detectable variation of the austenite composition, whether in the presence or absence of transformation products. There are relatively few direct references to stabilization in the literature. The stabilizing effect of room temperature aging and tempering on the subzero transformation of retained austenite has been clearly shown in plain carbon,6,8 low alloy6s7.8 and high alloy tool steels.10'5 ssa- with the as-hardened steel, the degree of stabilization increases with tempering time and temperature through

Jan 1, 1949

By D. Harrington

FROM 1870 to date, the coal production of Utah has been somewhat less than 85,000,000 tons. There have been at least three major disasters with total fatalities about 380; or approximately. 4.4 persons killed by mine explosions per million tons produced, a record that is decidedly bad. Even during the periods when there have been no disasters, such as the years 1914 to 1920, inclusive, the fatalities .in ordinary working ran about 5.4 per million tons produced, against 3.7 per, million tons. for the whole United States for the same years. The five-year period following the war, 1918 to 1922 inclusive, showed 4.7 fatalities per million tons, hence the fatality record in the coal mines of Utah has uniformly been in excess of the average of the coal mines of the entire country. Notwithstanding this poor record, Utah has given to the coal-mining world many excellent safety methods and practices and the Utah. coal mines in general take greater measures toward safe mining than do the coal mines of any other State; if practices and methods allowed and pursued in coal mines of other States were tried in Utah coal mines, there would be a succession of disasters. Utah's principal producing coal mines, operated by about eighteen companies and numbering less than forty, have comparatively thick seams. Very little coal under 5 ft. thick is being worked and practically none under 4 ft.; much, if not most, of the coal comes from seams in excess of 8 ft., some running as high as 30 ft. In thick seams in which coal is left on floor and roof, any dust found or made is entirely combustible. In addition, the thick seams induce the use of large capacity cars, handling which in rooms and other workings on fairly heavy grades (up to 10 or .12 per cent.) tends to cause haulage accidents. The thick seams give high ribs and roof, in which it is difficult to prevent slabs of coal or rock from dropping on workers and also difficult to keep free of gas and of coal dust. The coal is high volatile, running usually over 40 per cent and in some instances nearly to 50 per cent; hence is highly flammable. Most of the coals have very high resin content, the resin usually being in dust form, hence almost as highly flammable as black powder. At .least one-third of the mines give off methane and several give off other

Jan 8, 1925

By F. L. Ruhlman, Max C. Eastman

The termination of the recent war marked a major changc in the oil-field operations at. Elk Hills. Production was greatly curtailed, various experimental production projects were started, and a long-range exploratory program was inaugurated. Production was reduced from the wartime peak of 65,000 bbl per day to the current rate of about 8ooo bbl per day in order to maintain an available source of crude that can be drawn upon during a national emergency. The existing production rate is deemed essential to carry on the experimental production projects. These projects are being conducted to determine the best methods and means of maintaining the Reserve, shut in, but in a state of readiness to produce the maximum quantity of oil in the most expeditious manner. Projects now being investigated include: (I) protection of surface equipmerit; (2) repair of wells that might damage the reservoir; (3) gas injection; (4) water eneroachment, (5) gravity drainage. An exploratory program is being carried on to determine the amount of recoverable oil in the unexplored portions of the Reserve. The Shallow-zone exploration is practically completed, but owing to the complexity of the Stevens structure and the magnitude of the oil discoveries in the Stevens, exploration will probably continue in that zone for another two years. Introduction Summary of Development History of Elk Hills Although a detailed history of Elk Hills oil field is presented in various publications,1,2 a summary of its unusual development and production history will be given in order that the present problems may be more readily understood. The first development that resulted in commercial production was in the central part of the Reserve. The first well, Hay No. I, in sec 36-R,* was completed in January I9I9, and was soon followed by 37 Others in the same general area. It is commonly referred to as the Hay-Carman area and was shut in in stages from 1925 to 1934 as a result of litigation regarding the title to the land. Not being highly producti,, only about 6½ million barrels of oil with a large volume of gas was produced from the area prior to the shutdown. Shortly after the start of the development of the Hay-Carman area, drilling was started 6 miles east in sec 36-S' Tupman NO. I came in for 5000 bbl per day early in I92o, It was followed by more than 200 others in the next few years, and the field became one of major importance. Produc-

Jan 1, 1949

By E. N. Silverman

Mixtures of' MnS, ZFeO-SiO,, ZMnO.SiO, FeO, and MnO were prepared synthetically and used to study the planes ZFeO. Si0,-ZMnO.SiO,-MnS, FeO-MnO-MnS, and Fe0-MnO.Si0,-MnS in the quaternary system. Because the oxides and silicates studied flux MnS, inclusions in this system are partly liquid during rolling. Also, oxygen can modify subsurface inclusions through the reaction MnS + FeO—FeS + MnO during the soaking of ingots and the reheating of blooms and billets. NONMETALLIC inclusions in steel have long been a subject of study and conjecture because the properties of many steels are known to be affected by the the kind and amount of inclusions present. In free-machining steels, the type of inclusion present has a direct bearing on their machinability; in other steels, cleanliness is important and metallurgists direct their efforts at reducing the amount of non-metallic inclusions. Thus, the accumulation of knowledge about the formation and behavior of inclusions during all stages of steelmaking and processing should aid in improving the quality of steels and decreasing the production costs resulting from rejections. Previous studies of inclusions have contributed greatly to our understanding. The investigators have generally examined inclusions in finished steel. Boulger, Moorehead, and Garvey1 found that in Bessemer steels, low silicon contents results in globular sulfide inclusions with attendant high machin- ability ratings. Van vlack2 also found that low silicon contents favor inclusion morphology that contributes to high machinability ratings. Boquist and Stoll* found that silicon content affected sulfide inclusions and machinability of blooms, billets and bars more than did the finishing temperature in the range between 1775° and 2075°F. Carney and Rudolphy3 studied the distribution of sulfur, manganese, silicon, and carbon in a commercial ingot of resulfur-ized steel and found that silicon was concentrated near the bottom. This helped to explain why bottom cuts had poorer machinability. Klinger and Koch4 developed techniques for extracting inclusions from steel, and the technique devised by Gurry, Chris-takos, and stricker5 for extracting carbides can also be adapted to the study of inclusions. A different approach to the study of inclusions in steel consists of synthesizing the constituents that form inclusions and determining the phase eauilibria in the system that contains the constituents. The resulting phase diagrams can then be used to determine the effect of the various constituents upon each other. In this way, it becomes possible to under-

Jan 1, 1962

By P More

US 4,132,621-In the electrowinning of aluminum, the cells are aligned in a lengthwise direction so as to lessen the harmful influence of the induced magnetic fields Each cell is supplied with current from the preceding cell both via the head arid at least one side riser The output of the cathode bars is divided into two separate groups, the upstream group supplying the head of the subsequent cell arid the downstream group supplying the side risers of the subsequent cell This produces a substantial improvement in cell efficiency arid a greater regularity P Morel, J P Dugois, arid B Langon, assigned to Aluminium Pechiney. Jan 2, 1979 12 pp. (204¬243M) Filed 1-12-78 (868,861) Priority: France, 1-19-77 (77/2,213) US 4,134,806-Cells, anodes, arid methods for use in the electrowinning of nickel, cobalt, copper, zinc, or other metals from an acid ore leach solution or the like The cell is provided with vertically immersed stationary cathodes and stationary rod anodes which are noncorrodible by the electrolyte arid are electrocatalytic to the anode reaction. The spaced parallel anode rods are connected to electric current supply bars The anode rods have an electroconductive core made of a metal alloy arid a surface coating of an oxide of platinum or a platinum group metal The ratio of active cathode surface area to active anode surface area is preferably at least 3 0. De Nora arid C Traini, assigned to Diamond Shamrock Tech¬nologies, SA Jan 16, 1979 13 pp. (204-105R) Filed 9-15-77 (833,661) Priority Italy, 1-29-73 (19738 A/73). Same British 1,434,334-5, dated May 5, 1976 US 4,135,994-In the electrowinning of aluminum at a high current efficiency, the electrolytic bath is a mixed molten salt consisting of 2-15% by weight of aluminum trichloride, 15-83% of sodium chloride, 15-70% of combined calcium chloride arid magnesium chloride but riot more than 40% of calcium chloride, arid optionally up to 10% of barium chloride Preferably, plate-shaped graphite electrodes used for both cathodes and anodes are arranged in parallel inclined relation so that the axis in the lengthwise direction makes an angle of from 10° to 45° to the horizontal. T Ishikawa arid H Ichikawa, assigned to Nippon Light Metal Co Ltd Jan 23, 1979 4 pp (204-67) Filed 11-15-77(851,632) Same British 1,550,502, dated Aug 15, 1979

Jan 1, 1980

By Burton H. Boyum

Greater depth of exploration drill holes and increasing cost of drilling have been principal factors in reviving interest on the Mar-quette Iron Range in controlled directional drill-hole deflection. This deflection is obtained by the application of the Hall-Row wedging technique. Modifications were made in the technique and equipment in the effort to simplify and strengthen the procedure. The practice is similar in many respects to the oil well type of deflection with a whipstock. Introduction The deflection of diamond drill holes by wedging was a widespread practice in Canada, South Africa and the Lake Superior District as early as 1907 to 1920. Several basic schemes were used, with local variations.' The deflecting wedge assembly was the idea of Mr. Welldon and Mr. Payne-Gallwey operating under the supervision of Mr. William Gallagher of Johannesburg, South Africa. All schemes employed some means of plugging the old hole. A footpiece of various styles was placed in the hole on the plug. In some methods, the orientation of this piece was determined before placing the deflecting wedge. Some techniques permitted continuing the hole the same size after wedging, while others necessitated a size reduction. Interest in wedging diamond drill holes in the Lake Superior District waned after 1920. The Hall-Row patented system for deflecting holes was developed in Canada about 1918.2 Interest centers on the wedging process for the following applications: 1. Maintaining a given course and inclination of the drill hole. 2. By passing an obstruction in a drill hole. 3. Resampling an ore body. 4. Exploring an area overlain by surface conditions not favorable to drilling. During the period of 1913 to 1920, The Cleveland-Cliffs Iron Co. used the wedging technique under a variety of conditions. In general, the practice was not applicable again until 1946. Meanwhile the Hall-Row system of drill-hole deflection survived years of application as the best technique available. In the intervening years, our depth of exploration has increased as well as the overall cost of drilling. As exploration becomes deeper, there is the possible economy of cutting the ore body at a moderate distance from the parent hole without redrilling from surface. Thus a branch hole started near the mid-point of a deep hole can reach the ore horizon at a considerable offset from the parent hole. This permits a greater interval between surface drill holes as drilling becomes deeper. Our interest revived in the subject and a wedging program was initiated. General Description Results The maximum theoretical angular deflection possible, based on the deflecting

Jan 1, 1949