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By Arthur W. Gray

The thermal analysis of a metal or an alloy is ordinarily made with the aid of heating and cooling curves in which transitions are indicated by the rapid changes in curvature that accompany changes in the rate of heat absorption or evolution. Analysis by the method that depends on the change in thermal expansivity is not customary, partly, at least, because of the difficulties involved in making the necessary measurements. However, under certain circumstances, the dilatometric method of analysis may possess advantages over the thermometric method that will justify the additional trouble required. The addition of 1 per cent. of zinc to an alloy has been found to produce upon the volume changes that take place during transition effects that suggest the possibility of using the dilatometric method of thermal analysis as a rather sensitive means of obtaining chemical information. Although the illustrations presented in this paper are drawn from data obtained during an investigation of dental amalgams, similar phenomena can doubtless be observed with other alloys. Some of the results found during an investigation made in 1917l have been confirmed by data on the thermal expansivity of amalgams published by Souder and Peters of the Bureau of Standards in reporting tests of dental materials.2 Although the Bureau of Standards made experiments for the purpose of discovering effects of including zinc as one of the constituents of a dental alloy—a matter much discussed in dental literature but without the presentation of reliable experimental evidencae to support the views of either side—the reports of the tests made by the Bureau give the impression that certain striking phenomena associated with the presence of zinc were not noticed. Among such phenomena arc those connceted with the conditions that determine whether or riot a specimen of amalgam becomes covered with droplets from which crystals develop.

Jan 1, 1921

By Frank S. Gardner, Morris Cohen, Dara P. Anita

There is a conspicuous lack of information in the literature on the precise role played by residual quantities of austenite in heat-treated steels. While retained austenite may be expected to have significant effects on such important properties as the impact resistance of tools and carburized parts and the dimensional stability of dies and gauges, attempts to study these problems systematically have suffered from the absence of a reliable technique for ascertaining absolute amounts of austenite. With such a technique, not only could the relation between residual austenite and service behavior be investigated, but the chemical and heat-treatment factors that control the quantity of the austenite could also be established. Thus, the retained austenite content could then be regulated in accordance with the results desired. The presence of retained austenite may be inferred by observing the changes in properties (hardness, specific volume, electrical resistance, etc.) due to its decomposition on subatmospheric cooling1 or on tempering,2 but these indirect measurements are not readily translated into percentages of austenite. Quantitative determinations have been achieved in special cases by means of dilatometric3 and magnetic4,5 measurements; but the former procedure requires that observations be conducted during the hardening and involves difficult calibrations that limit its applicability, while the magnetic procedure is very sensitive to extraneous influences and depends upon assumptions that can only be considered as approximate in an absolute sense. Furthermore, both the dilatometric and magnetic effects are volume properties, and cannot be conveniently utilized to explore variations in retained austenite from point to point in a suecimen. Some microstructures lend themselves to accurate evaluation of retained austenite contents by metallo-graphic methods,3 but such instances are not too common, and at best, the procedure is tedious. The characteristic X-ray diffraction lines of austenite permit positive identification of its presence; and in the present paper the intensities of these lines, or the corresponding densities* on photographic film, are employed to measure the amount of the retained austenite. In order to cancel the effect of uncontrollable variations in the X - ray exposure and film - development conditions, a standard reference line is Superimposed on each film by maintaining a foil of aluminum in the path of the incident X-ray beam during the entire exposure. With different samples of steel and the same foil, the ratio of the density of some one austenite line to the density of

Jan 1, 1943

By R. A. Meussner, R. J. Goode

Six intermediate phases occur in the Nb-Zn sysThese phases form by peritectic reactions at 1120°, spectively. The Nb Zn 15 phase appears as the minor phase in the eutectic structure, and the terminal phases remain nearly pure niobium and zinc even at high temperature. Vapor -pressure measurements on the four high-temperature phases (Nb Zn to Nb Zn 3) permitted estimates of the composition limits of these phases and the calculation of approximate values of AFO, AH°, and AS°. 1 HE present study of the constitution of the binary Nb-Zn system was a part of an analysis of the mechanism by which coatings of the Nb-Zn intermediate phases protect niobium against oxidation at high temperature.' Since the primary interest in these phases was in coating service, attention in this study was given principally to the four phases stable at high temperature with only cursory attention to the two low-temperature phases. The solubility studies of niobium in zinc by Martin, Knighton, and Feder2 and the reports from the present study of the Nb-Zn coating represent the only published data pertaining to this system. Previously Hodge, Evans, and Hoskins, in an experimental survey, had noted that niobium was not resistant to attack by molten zinc, but no further observations were reported. EXPERIMENTAL PROCEDURES a) General. The nature of the binary Nb-Zn system precluded the use of more conventional methods of determining the phase equilibria such as thermal analyses of a series of cast alloys. An extrapolation of the liquidus data of Martin, Knighton, and Feder2 to higher temperatures suggested that the solubility of niobium in zinc would remain low in the entire temperature range of interest. The preliminary results of the present studies showed that all of the high-temperature intermediate phases form by peritectic reactions. Thus the sluggish nature of this type of reaction and the steepness of the liquidus indicated that thermal analyses would not yield reliable data. The peritectic reactions, of course, precluded the direct formation of samples of the individual phases from the melt. b) Materials. The niobium and zinc used in the present studies were of high purity. The niobium, in the form of 0.1-in.-diameter rods, contained 30 ppm 0, 30 ppm N, and 15 ppm C. Aside from 0.05 pct Ta, the metallic impurities (iron, titanium,

Jan 1, 1965

By Nicholas J. Grant, Klaus M. Zwilsky

EVER since the unusual high temperature creep resistance and structure stability of SAP (Sintered Aluminum Powder) and similar aluminum-alumina alloys were reported,'," there has been a need to determine whether other metal-metal oxide (or other hard stable particle) alloys, not so ideal as the Al-Al 2 O 3 system, would show similar high temperature strength and stability. Of the many possible methods of obtaining a metal-metal oxide alloy,a one that offers many practical and theoretical advantages is the simple mechanical blending of metal powders with hard stable particles, followed by pressing, sintering, and hot extruding. With this purpose in mind copper powder and silica and alumina were selected for experimentation because these materials are readily available, cheap, reliable, and lend themseives te the simplest processing and testing. Starting Materials—Two sizes of electrolytically deposited copper powders were used, a —200 mesh powder referred to as A powder in this investigation and a —325 mesh powder referred to as C powder. Silica was added in the form of pure Potter's flint from which a —10µ fraction had been separated. Alumina of the a variety was used in two size ranges. The first was a —10µ fraction separated from a coarser aggregate, the second a commercial product of 0.3µ average diam manufactured by Linde Air Products. Preparation of Powders—Five-hundred gram batches of A copper with 1, 3, and 10 volume pct of each of the three oxides mentioned above were prepared, as well as C copper containing 1, 3, and 10 volume pct of —lop silica. Powders were weighed out carefully and blended by ball milling in air for 24 hr. Since this treatment resulted in surface oxidation of the copper, the charge was hydrogen reduced at 260°C for 5 hr. The next step consisted of hydrostatically compacting the powder into a shape suitable for the required hot working. For this purpose a slug about 11/2 in. in diam and 31/2 in. in length was produced by placing the mixed powders into a rubber sleeve, holding in a perforated steel canister, and rubber stoppering at the ends; the assembly was then subjected to a hydrostatic pressure of 50,000 psi. The air was evacuated from the assembly prior to pressing in order to prevent

Jan 1, 1958

By Dara P. Antia, Morris Cohen, Frank S. Gardner

THERE is a conspicuous lack of information in the literature on the precise role played by residual quantities of austenite in heat-treated steels. While retained austenite may be expected to have significant effects on such important properties as the impact resistance of tools and carburized parts and the dimensional stability of dies and gauges, attempts to study these problems systematically have suffered from the absence of a reliable technique for ascertaining absolute amounts of austenite. With such a technique, not only could the relation between residual austenite and service behavior be investigated, but the chemical and heat-treatment factors that control the quantity of the austenite could also be established. Thus, the retained austenite content could then be regulated in accordance with the results desired. The presence of retained austenite may be inferred by observing the changes in properties (hardness, specific volume, electrical resistance, etc.) due to its decomposition on subatmospheric cooling1 or on tempering,2 but these indirect measurements are not readily translated into percentages of austenite. Quantitative determinations have been achieved in special cases by means of dilatometric3 and magnetic4,5 measurements; but the former procedure requires that observations be conducted during the hardening and involves difficult calibrations that limit its applicability, while the magnetic procedure is very sensitive to extraneous influences and depends upon assumptions that can only be considered as approximate in an absolute sense. Furthermore, both the dilatometric and magnetic effects are volume properties, and cannot be conveniently utilized to explore variations in retained austenite from point to point in a specimen. Some microstructures lend themselves to accurate evaluation of retained austenite contents by metallographic methods,3 but such instances are not too common, and at best, the procedure is tedious. The characteristic X-ray diffraction lines of austenite permit positive identification of its presence; and in the present paper the intensities of these lines, or the corresponding densities* on photographic film, are employed to measure the amount of the retained austenite. In order to cancel the effect of uncontrollable variations in the X-ray exposure and film-development conditions, a standard reference line is superimposed on each film by maintaining a foil of aluminum in the path of the incident X-ray beam during the entire exposure. With different samples of steel and the same foil, the ratio of the density of some one austenite line to the density of

Jan 1, 1943

By Morris Cohen, Dara P. Anita, Frank S. Gardner

There is a conspicuous lack of information in the literature on the precise role played by residual quantities of austenite in heat-treated steels. While retained austenite may be expected to have significant effects on such important properties as the impact resistance of tools and carburized parts and the dimensional stability of dies and gauges, attempts to study these problems systematically have suffered from the absence of a reliable technique for ascertaining absolute amounts of austenite. With such a technique, not only could the relation between residual austenite and service behavior be investigated, but the chemical and heat-treatment factors that control the quantity of the austenite could also be established. Thus, the retained austenite content could then be regulated in accordance with the results desired. The presence of retained austenite may be inferred by observing the changes in properties (hardness, specific volume, electrical resistance, etc.) due to its decomposition on subatmospheric cooling1 or on tempering,2 but these indirect measurements are not readily translated into percentages of austenite. Quantitative determinations have been achieved in special cases by means of dilatometric3 and magnetic4,5 measurements; but the former procedure requires that observations be conducted during the hardening and involves difficult calibrations that limit its applicability, while the magnetic procedure is very sensitive to extraneous influences and depends upon assumptions that can only be considered as approximate in an absolute sense. Furthermore, both the dilatometric and magnetic effects are volume properties, and cannot be conveniently utilized to explore variations in retained austenite from point to point in a suecimen. Some microstructures lend themselves to accurate evaluation of retained austenite contents by metallo-graphic methods,3 but such instances are not too common, and at best, the procedure is tedious. The characteristic X-ray diffraction lines of austenite permit positive identification of its presence; and in the present paper the intensities of these lines, or the corresponding densities* on photographic film, are employed to measure the amount of the retained austenite. In order to cancel the effect of uncontrollable variations in the X - ray exposure and film - development conditions, a standard reference line is Superimposed on each film by maintaining a foil of aluminum in the path of the incident X-ray beam during the entire exposure. With different samples of steel and the same foil, the ratio of the density of some one austenite line to the density of

Jan 1, 1943

By A. U. Seybolt

DURING the course of experiments involving oxygen equilibrations with a high-purity Pd-5 at. pct Rh alloy, the appearance of a subscale was noted. Most of the heat treatments in a pure oxygen atmosphere were performed at 900°C. The presence of the subscale was noted when the oxygen partial pressure was in excess of approximately 95 mm, up to 1 atm, the highest pressure used. According to available thermodynamic information' on the free energy of formation of Rh2O3 (the only reliably reported solid oxide of rhodium), this oxide should not be stable under these conditions, nor, of course, any oxide of palladium. Extraction of the subscale from the matrix was affected by treatment with aqua regia, and the resulting X-ray diffraction powder pattern is shown in Table I. This pattern is not that of Rh2O3, nor that of any known rhodium or palladium oxide. It can be indexed on a hexagonal lattice with a. = 5.22Å and co = 6.0Å. In addition to this unknown material, there was a weak Rh2O3 pattern. An X-ray fluorescence analysis of the powder gave 3214 palladium counts per sec and 5381 rhodium counts per sec, thus indicating the likelihood of a double oxide of palladium and rhodium. In view of the fact that the above result was obtained on a single sample, it is perhaps best not to insist upon the above ratio of about 0.6, but possibly to tentatively assume 0.5 or 1/1. The small amount of Rh2O3 in the X-ray pattern might have occurred on cooling, and it seems possible that the double oxide, below some temperature level, is not as stable as Rh2O3. To examine this point, some of the extracted double oxide was heated on a sheet of pure palladium in air at 900°C, and allowed to furnace-cool over a period of several hours. The X-ray diffraction pattern of the powder showed approximately the same intensity of Rh2O3 and the "hexagonal" oxide as before, but, in addition, a rather faint pattern of another crystalline species made its appearance. This finding again suggests partial transformation of the major (double) oxide to other oxides on cooling from 900°C. Application of the phase rule shows that only one equilibrium oxide (subscale) could have been present at temperature. Vacuum-fusion, oxygen analysis of the extracted subscale showed 7.7 ± 0.7 pct O. Combining this information with that of the X-ray fluorescence analysis suggests the formula PdRhO. This compound should have an oxygen content of 7.07 pct, which is within the range of error of the oxygen analysis. However, until a more careful stoichiometric study is made, it is suggested that the formula be written

Jan 1, 1965

By F. J. Cuddeback

For low-head pumping of small quantities of water, the water jet, or hydraulic educter, has been used to advantage by Eagle-Picher Mining and Smelting Co. in the Tri-State district. Water-jet pumps are used for draining sumps and pockets up to 15 ft. in depth. They have been used very successfully when only moderate amounts of water are encountered in taking up bottom. A small, easily handled unit is desirable in this work, especially while opening and deepening a new stope. Small air pumps are convenient but can be used only on the day shift, when air is available. Obviously, a jet pump of smaller capacity but operating 24 hr. prevents lost time at the start of each shift. No tests have been made on their power efficiency, but admittedly it is low. However, for certain kinds of work this is offset by their handiness, low initial cost, low upkeep, and reliability. They will handle slime and sand without ill effect, and will continue to pump indefinitely on air. This foolproof 24-hr. performance has led to their continued use at some places even after electric pumps with better power efficiency could have been installed. The success of jet pumps depends largely upon a cheap source of high-pressure water. Owing to mine depths in the Tri-State district, pump pressures range from 100 to 150 Ib. per sq. in. In many mines it is common practice to handle the normal inflow water with triplex pumps ranging in size from 3 to 8 in. The pumps operate 24 hr. per day, and, in order to handle emergency conditions, are speeded slightly faster than necessary to pump the normal inflow. The sump level is governed by controlling the by-pass water with a butterfly valve and float. This method is somewhat wasteful of power, but permits the pumps to operate with a minimum of attention. Such an installation is visited once a day to check lubrication. Hence, if some of this water, normally by-passed to the main sump, were used to operate a jet pump, the power cost could be considered low regardless of efficiency. Figs. I and 2 show two water jets that have done satisfactory work. The one in Fig. 2, made up entirely of pipe fittings, may be of interest partially because of its novelty, but does better work than its appearance indicates. The pipe fittings for this jet as shown cost $2.20. Some improvement in its design may be made by cutting out the 135 by 1¼-in. reducer to a smoother taper as shown by dotted lines. A 3-in. suction pipe is sometimes used in order that the discharge may be as straight as possible. A 2-in. discharge line has been used frequently, but 3-in. pipe is used where several hundred feet of discharge is required.

Jan 1, 1946

By William B. Stephenson

The paper describes efficient and effective methods of automatically controlling sand pump installations. Particular reference is made to liquid-level controls actuating variable speed pump-driving units. Included is a discussion of various combinations of equipment, with schematic drawings. HERETOFORE many sand pump installations in the mining and metallurgical field involved guesswork as to the size of the pump and then simply direct-connecting it to a constant speed motor which was often large enough to do twice the work required. Considerable thought was given to mill location in an effort to avoid as much pumping as possible. Hillside design of mills with gravity flow of tailing was much to be desired. Power costs were low, construction was relatively cheap, and labor in many places meant nothing in comparison to the values derived from the ores being treated. Today most of these conditions are reversed. Ores are becoming more complex with lower values per ton of ore treated. Power is more expensive, construction is higher, and labor definitely takes a very important place in the profit and loss statement. Each piece of equipment incorporated in the design of a new mill is selected to provide highest efficiency based on careful metallurgical analysis of the ore to be treated both in good and poor markets. Each is designed with its flexibility in mind and with provision for adjustments in its performance to meet actual conditions in the operation of the mill. Sand pumps have taken an important position in mill design. Operators the world over are relying more and more on the performance of a sand pump in the efficient operating of their plant. Many ordinary jobs are being done today with pumps driven through adjustable pitch diameter V belt drives in order that changes in pump speed can be made easily to meet actual operating conditions. Operating costs have long since proved the folly of operating a pump at too high a speed for the volume and head to be overcome. Metallurgical results have shown the benefits derived from a smooth flow as contrasted with a surging flow from an uncontrolled pump. Construction costs have risen to such an extent that surge bins and other means formerly employed must be omitted from today's flowsheet. Several installations of considerable size and involving the use of automatic pump speed control have proved the adaptability of such controls since they were placed in service in recent years. In the following presentation each system discussed and illustrated schematically has been installed in one or more instances and has proved itself reliable and definitely economical from the standpoint of capital investment, operation and maintenance. Variable Volume-Head Speed Control: Probably the most popular, effective and efficient automatic control setup for sand pumping installations is the one shown schematically in fig. 1. Commonly used

Jan 1, 1951

By Nicholas Kowall, K. L. Clark

Maximum furnace efficiency and close control of final steel composition demand that the steel melter be able to follow closely the variations in the carbon content of the bath. For many years, the fracture test has been used by melters for estimating carbon, because it requires only a very short time to pour a sample into a chill mold, cool it in water, break it with a sledge hammer, and observe the fracture. After long experience gained from the observation of such fractures, most melters are able to estimate the carbon content of steel with amazing accuracy, particularly in the lower carbon ranges. Notwithstanding the utility of the fracture test, there has been widespread interest in other methods for rapid carbon determination to supplement it and to ensure against possible errors in human judgment. Several methods, based upon measurement of magnetic properties as functions of carbon content, have been described in the literature1-6 and have been found to give reasonably reliable results in plant practice when scrap composition is known and controlled. A difficulty encountered in the use of analyzers of the magnetic type is that alloying elements do change the relationship between carbon content and magnetic properties and it becomes necessary to establish calibration curves for all the expected combinations of alloy residuals that are not oxidized in the bath. The work reported here is of an investigation of a method that is independent of alloying elements normally present in constructional steels, being based upon the relatively well-known fact that in plain carbon and low-alloy steels martensitic hardness is a function of carbon content alone. Work oF Other Investigators In I938, Burns, Moore and Archer published & curve? that showed that the hardness of martensite is a function of carbon from 0.10 to 0.50 per cent and is independent of grain size or alloy content, at least within the rallge found in construc-tional S.A.E. compositions. Some of the deeper hardening types investigated, however, contained carbon to a maximum of only o.2o per cent. Using this principle, Kern8 developed a method of rapid carbon determination for S.A.E 43xx steels, His procedure consisted of chill-casting a test bar that was large enough to give a a that could be prepared for Brinell indentations. The test piece was quenched immediately after solidi fication was complete and hardness readings were taken, so that the carbon content could he read from an experimentally determined curve giving the relationship between as-quenched hardness and carbon. Experimental Work Although Kern's work had been done with a relatively deep-hardening steel, it

Jan 1, 1944

By W. H. Herrnstein, F. H. Beck, M. G. Fontana

Sulfur solubility in a iron was measured in the 750 to 890°C temperature range and was found to be insensitive to ferrite purity within a limited composition range. The permeability of sulfur in ferrite was determined from the internal sulfidation of Fe-Mn alloys. From the solubility and permeability results, the diffusivity of sulfur in ferrite could be calculated. These results are summarized as follows: Dissolved sulfur decreased the lattice parameter of ferrite. The effect of dissolved sulfur on the tensile properties of ferrite at low temperatures was also determined. SINCE sulfur is an important residual impurity in commercial irons and steels, effects associated with the presence of sulfur as a solute in iron are of considerable practical interest. Unfortunately, certain basic information relative to the Fe-S system appears to be lacking in the literature, e.g., the effect of dissolved sulfur on the lattice parameter and mechanical properties of ferrite. In addition, discrepancies exist in previously reported results for the solubility of sulfur in ferrite. These discrepancies raise questions regarding the sensitivity of sulfur solubility to the purity and microstructure of iron. This study was undertaken primarily in an effort to obtain reliable data on the solubility of sulfur in ferrite. Additional objectives included determination of the permeability and diffusivity of sulfur in ferrite by the internal sulfidation method and determination of the effect of dissolved sulfur on the lattice parameter and tensile properties of ferrite. EXPERIMENTAL METHOD Three grades of iron, encompassing a range of impurity levels, were employed in the study. The grades were designated VME (vacuum-melted electrolytic), SPZR (single-pass zone-refined), and MPZR (multipass zone-refined). The composition of each grade is given in Table I. Poly crystalline and single-crystal strip specimens were employed in the solubility experiments. Uniform grain size strip (ASTM 3 to 5) of 0.005 to 0.020 in. thickness was obtained by alternate cold reductions of 60 thickness 60 to 80 pct and recrystallization at 650°C for i hr in pure, dry argon. Single-crystal specimens were produced in 0.010-in.-thick SPZR iron strip by the strain-gradient anneal technique. Recrystallized strip 0.25 in. wide was strained until a Luders band or bands had propagated over the length of the strip; the strip was then annealed by drawing it through a 150°C per in. gradient (890°C peak temperature) at 1 in. per hr in an atmosphere of pure, dry argon. Laue photographs of the crystals produced exhibited no discernible asterism. Specimens were equilibrated with H-H, atmospheres at temperatures between 750" and 890" by one of two methods, each of which makes use of the reaction: The encapsulation sulfurization method was employed in the majority of the solubility experiments. A strip

Jan 1, 1969

By Jules E. Jenkins

IN the past quarter century the seismograph has played an increasingly important role in evaluating vibratory effects transmitted to adjacent communities by industrial blasting operations. In this period research has advanced through two major phases—from falling pin seismometers to three-component recording seismographs. The initial phase of this research is now regarded as the era of recording, during which the seismograph merely recorded occasional events. It has emerged from this stage into the era of control and analysis and in this later period has been recognized as a full-fledged industrial tool. Although the falling pin machines of earlier years indicated probable amplitudes of industrial blasting vibrations, they gave no reliable measure of such displacements, nor did they provide essential information concerning direction or frequency of motion. The first contribution of the three-component recording seismograph was the weight-for-distance formula developed by the U. S. Bureau of Mines. This empirical formula enabled users of commercial explosives to determine beforehand the probable vibratory effects of a blast when the weight of the explosives charge and the distance from the shot point were known. This formula has withstood the test of time and is still applicable for blasts detonated by instantaneous methods. The second major contribution of the three-component recording seismograph followed the introduction in 1945 of short period or millisecond delay detonation. This might be described as a two-stage contribution, the first of which revealed a 50 pct reduction in the vibration magnitude when millisecond detonation was used rather than instantaneous discharge. This second part of this double contribution led to the discovery of the vibration dip phenomena, see Fig. 1. In Fig. 1 the horizontal coordinates indicate the displacements amplitude in inches, and the vertical coordinates, the explosive weight in pounds. The top curve is that of the U. S. Bureau of Mines for instantaneous detonation. Its curvature conforms to the two-thirds power of the explosive weight as provided in the weight-for-distance formula; hence the vibratory effects increase in proportion to an increase in the explosive charge. If the other curves shown below are temporarily disregarded, it may be considered that the entire area below this top curve represents both useful and waste energy. As mentioned previously, when millisecond delay detonation was first investigated it was found that in general the U. S. Bureau of Mines curve could be decreased by about 50 pct, or to the position of the middle curve. At the outset it was assumed that this curve would likewise increase in some proportion to the explosive charge, as did the top curve, that is, the curve would indicate a continuous upswing. As seismographic data accumulated this assumption was found to be erroneous in part. It was discovered that

Jan 1, 1957

By K. L. Clark, Nicholas Kowall

Maximum furnace efficiency and close control of final steel composition demand that the steel melter be able to follow closely the variations in the carbon content of the bath. For many years, the fracture test has been used by melters for estimating carbon, because it requires only a very short time to pour a sample into a chill mold, cool it in water, break it with a sledge hammer, and observe the fracture. After long experience gained from the observation of such fractures, most melters are able to estimate the carbon content of steel with amazing accuracy, particularly in the lower carbon ranges. Notwithstanding the utility of the fracture test, there has been widespread interest in other methods for rapid carbon determination to supplement it and to ensure against possible errors in human judgment. Several methods, based upon measurement of magnetic properties as functions of carbon content, have been described in the literature1-6 and have been found to give reasonably reliable results in plant practice when scrap composition is known and controlled. A difficulty encountered in the use of analyzers of the magnetic type is that alloying elements do change the relationship between carbon content and magnetic properties and it becomes necessary to establish calibration curves for all the expected combinations of alloy residuals that are not oxidized in the bath. The work reported here is of an investigation of a method that is independent of alloying elements normally present in constructional steels, being based upon the relatively well-known fact that in plain carbon and low-alloy steels martensitic hardness is a function of carbon content alone. Work oF Other Investigators In I938, Burns, Moore and Archer published & curve? that showed that the hardness of martensite is a function of carbon from 0.10 to 0.50 per cent and is independent of grain size or alloy content, at least within the rallge found in construc-tional S.A.E. compositions. Some of the deeper hardening types investigated, however, contained carbon to a maximum of only o.2o per cent. Using this principle, Kern8 developed a method of rapid carbon determination for S.A.E 43xx steels, His procedure consisted of chill-casting a test bar that was large enough to give a a that could be prepared for Brinell indentations. The test piece was quenched immediately after solidi fication was complete and hardness readings were taken, so that the carbon content could he read from an experimentally determined curve giving the relationship between as-quenched hardness and carbon. Experimental Work Although Kern's work had been done with a relatively deep-hardening steel, it

Jan 1, 1944

By S. A. LoPilato, J. T. Smith

SEVERAL techniques have been evaluated for cooling the throat area of rocket-nozzle inserts to prevent erosion or fracture of the inserts during exposure to high operating temperatures and pressures. Self-cooled composites, such as infiltrated tungsten, have shown considerable promise for these applications. These composites can be fabricated by infiltrating the refractory matrix with a lower-melting metal or non-metal which is insoluable in tungsten. During firing, the lower-melting substance undergoes a series of continuous endothermic phase changes which absorb sufficient heat to maintain the nozzle matrix material at or below a safe operating temperature. At present, the state-of-the-art has reached a point where the refractory matrix density and microstruc-ture have been established as the critical parameters to be controlled for optimum self-cooled performance.'" Nondestructive testing has been utilized to ensure that porous tungsten billets were of uniform density and free from cracks or other defects prior to fabrication into rocket nozzle inserts. Ultrasonic-velocity techniques have been employed because of their reliability and reproducibility. The purpose of this note is to present and interpret the test data developed for porous tungsten matrices. For evaluation purposes, tungsten powders with Fisher subsieve sizes of approximately 4 and 18 p have been obtained for study from four commercial sources: the General Electric Co., Wah Chang Corp., Fansteel Metallurgical Corp., and Kennametal, Inc. Porous tungsten matrices were fabricated from the powders by hot pressing in induction-heated graphite die assemblies. Typical billets ranged from 3 in. diam, 2 in, high to 5 in. diam, 5 in. high. The ultrasonic-velocity measurement technique employed was through transmission, pulse echo at a frequency of 1.0 mc using matched barium titanate crystal transducers. The testing equipment included a pulsed ultrasonic generator, an amplifier, a specimen holder, and an oscilloscope, as shown in Fig. 1. The porous tungsten thickness was measured to i 0.0005 in, with precision micrometers while the oscilloscope achieved 0.02 psec time measurement accuracy. The time for a sound wave to pass through the billet, the bulk wave velocity, was calculated to 0.5 pct using Eq. [l]: V-} where V = bulk wave velocity, in. per psec, T = specimen thickness, in., and / = time, psec. To develop inspection standards, the bulk density of a porous tungsten billet was determined by the ASTM water-immersion technique.3 The ultrasonic-velocity measurements were completed at seventeen positions for each billet and averaged to develop a characteristic standard velocity for a particular tungsten powder at several density levels. A plot of ultrasonic velocity vs density is presented in Fig. 2 for six different tungsten powders. This graph has been established as

Jan 1, 1967

By R. W. Brown, J. L. Loper

The process of sand erosion has been harnessed to perform a useful function—the directed perforating of oilfield tubular goods and formation rock. In this process the sand is carried by a liquid medium and the resrrlting slurry is forced through a nozzle at an extren~ely high velocity. Upon impingement against casing or formation, the fast-moving sand particles erode a perforalion in the casing followed by cavity formation in the medium behind the casing. The many factors influencing the rate and extent of this penetration are inherently difficult to establish experimentally. Equations describing submerged jet behavior have been applied to these conditions. The following paper develops the equations for predicting the performance of the perforating jet. INTRODUCTION The cutting power of high-velocity sand has been well known in the petroleum industry for many years. Sand carried by a high-velocity gas stream causes severe erosion. This effect has been the cause of numerous production problems in certain areas. It was logical to expect that this phenomenon would one day be adapted to useful industrial applications. Development of mobile, high-pressure, high-horsepower pumping equipment in the last decade has made this possible. The sand erosion process involves pumping a fluid containing abrasive solids through a set of nozzles at a high differential pressure (2,000 to 4,000 psi). The pressure conversion into kinetic energy imparts high velocity to the sand particles which, upon impact with the formation face or casing wall, erode the material in an organized pattern. This paper attempts to establish the effects of the various parameters and to predict the performance and limitations of the process. The following factors will be considered: nozzle differential pressure, perforation size, sand concentration, nozzle stand-off distance and backpressure. In general, this discussion is presented along theoretical lines and is substantiated by field results and data where reliable field data exists. POWER EQUATIONS The penetration rate of a high-velocity hydraulic jet is proportional to the power or energy of the jet at the point in quesion. The power of the submerged jet will decrease with distance (or penetration) into the cavity created by the jet. As the cavity is extended into the formation, the power of the jet diminishes to a value equal to the threshold cutting power of the particular formation which is defiined as the lowest power level at which the formation will be abraded by the jet. Obviously, when this point is reached, no further cutting of the formation can occur. It is assumed that this power level for a particular formation is a function of the hardness of that formation. The following equation can be written for the hydraulic process of formation abrasion.

By William B. Stephenson

The paper describes efficient and effective methods of automatically controlling sand pump installations. Particular reference is made to liquid-level controls actuating variable speed pump-driving units. Included is a discussion of various combinations of equipment, with schematic drawings. HERETOFORE many sand pump installations in the mining and metallurgical field involved guesswork as to the size of the pump and then simply direct-connecting it to a constant speed motor which was often large enough to do twice the work required. Considerable thought was given to mill location in an effort to avoid as much pumping as possible. Hillside design of mills with gravity flow of tailing was much to be desired. Power costs were low, construction was relatively cheap, and labor in many places meant nothing in comparison to the values derived from the ores being treated. Today most of these conditions are reversed. Ores are becoming more complex with lower values per ton of ore treated. Power is more expensive, construction is higher, and labor definitely takes a very important place in the profit and loss statement. Each piece of equipment incorporated in the design of a new mill is selected to provide highest efficiency based on careful metallurgical analysis of the ore to be treated both in good and poor markets. Each is designed with its flexibility in mind and with provision for adjustments in its performance to meet actual conditions in the operation of the mill. Sand pumps have taken an important position in mill design. Operators the world over are relying more and more on the performance of a sand pump in the efficient operating of their plant. Many ordinary jobs are being done today with pumps driven through adjustable pitch diameter V belt drives in order that changes in pump speed can be made easily to meet actual operating conditions. Operating costs have long since proved the folly of operating a pump at too high a speed for the volume and head to be overcome. Metallurgical results have shown the benefits derived from a smooth flow as contrasted with a surging flow from an uncontrolled pump. Construction costs have risen to such an extent that surge bins and other means formerly employed must be omitted from today's flowsheet. Several installations of considerable size and involving the use of automatic pump speed control have proved the adaptability of such controls since they were placed in service in recent years. In the following presentation each system discussed and illustrated schematically has been installed in one or more instances and has proved itself reliable and definitely economical from the standpoint of capital investment, operation and maintenance. Variable Volume-Head Speed Control: Probably the most popular, effective and efficient automatic control setup for sand pumping installations is the one shown schematically in fig. 1. Commonly used

Jan 1, 1951

By H. C. Johnson, J. K. Elliott

One of the primary requirements for successful operation of an enriched gas-drive project is to control the composition of injection gas. This can become a serious and difficult problem, particularly in cases where the enrichment material is being furnished from a number of field -produced gas streams. It is possible to effect control of the injection gas composition through frequent or continuous sampling; however, this can be extremely costly and, in many cases, impractical due to laboratory requirements of time. Another alternative would be to provide a calculation technique which would be flexible and sufficiently accurate to predict composition of the liquid and gas streams of interest at any point in the system. The purpose of this paper is to discuss a technique that was used successfully on an operating enriched gas-drive project for developing information which could be used for controlling composition of the injected gas. FIELD OPERATIONS The particular field (hereafter called Example field) in the example operation being discussed is composed of four oil reservoirs (A. B, C and E) and one gas condensate reservoir (D). Casinghead gas from the oil reservoirs and gas from the gas condensate reservoir are gathered through a field gathering system as shown in Fig. I for injection into Reservoir C. The gas mixture which is recovered from the five reservoirs for injection purposes is composed of gases liberated in 19 individual separators, each operating at a separate temperature and pressure. PROPOSED CALCULATION TECHNIQUE It is well known that vapor-liquid equilibrium calculations in general use throughout the petroleum industry can be used to predict reliably the phase behavior of hydrocarbon mixtures, particularly at pressures less than 1,000 psig. It is then a simple matter to account for the material on a ComPonent basis by m''ing flash and material balance calculations at each separation point in a hydrocarbon system. Accordingly, it was proposed to use vapor-liquid equilibrium and material balance cal- culations with a medium-sized electronic digital computer as a basis for developing a control procedure for use in controlling injection gas composition in the enriched gas-drive project. Although the approach is a simple one, the numerous vapor-liquid equilibrium calculations involved make the problem laborious; in this particular case, it would have been impractical to make sutficiently complete analysis without the aid of digital computing equipment. SAMPLING AND VERIFICATION OF CALCULATION PROCEDURE To obtain representative gas and liquid stream samples and to provide a quantitative measure of overall system Performance for comDarative purpLses, a thorough test of the field and plant system was conducted in the summer of 1957. Oil production at each battery was sta-

By James E. Berryman

A method is presented for calculating the pressure depletion performance of a gas-condensate reservoir from the original reservoir fluid composition using the laboratory determined pressure-production history and retrograde liquid accumulation as guides. Equilibrium vaporization ratios for this calculation were modified from published data until the calculated dew point pressure and retrograde liquid accumulation agreed with the values observed in the laboratory. The calculated results are compared with the produced gas composition determined by low temperature analysis during constant volume laboratory experiments of pressure depletion behavior. This comparison shows that the calculation procedure is adequate for determination of gas phase composition. Data from field separation tests in low temperature separators are presented which verify the applicability of published equilibrium vaporization ratios for a wide range of separator conditions. INTRODUCTION A reliable prediction of the pressure depletion performance of a gas-condensate reservoir is necessary in determining reserves and evaluating field separation methods. The predicted performance is also used in planning future operations and studying the economics of projects for increasing liquid recovery. Because the flow of fluid in a volumetric gas-condensate reservoir is usually single phase flow, the pressure-depletion per-formake is primarily a function of the phase behavior of the reservoir fluid. The properties of a gas-condensate system of major importance are: (1) compressibility factor at reservoir temperature and pressure; (2) dew point pressure; (3) composition changes of the vapor phase with pressure depletion; (4) recovery of original in-place hydrocarbons at any pressure; and (5) retrograde condensate accumulation. These properties are most generally determined by a pressure depletion-type experiment on recombined separator gas and liquid samples in the laboratory. ldeally the pressure-depletion performance can be calculated from the composition of the original reservoir fluid if the reservoir temperature and initial pressure are known.1,2,3 It has been reported "... comparison of such computations with depletion-type ex-periments on recombined samples in the laboratory have yielded results that appeared to be entirely adequate.". The success of such calculations is determined by the equilibrium vaporization ratios chosen, especially those for the higher boiling point hydrocarbons. It is the purpose of this paper to present a method for computing the change in composition of the vapor phase during pressure depletion by production using laboratory determined properties of the system to guide the calculation and to illustrate the use of the method with data from the Cockfield "D" sand of Washington field, St. Landry Parish, La. Results of field tests and laboratory analysis are included. As a result of this reservoir fluid study, a cycling program has been evaluated, the fidd has been unitized, and the cycling started in July, 1956.

Jan 1, 1958

By J. L. Taylor, P. Duwez

PARTIAL phase diagrams of titanium with iron, cobalt, and nickel have been established by previous investigators.1-3 These diagrams seem to be reliable, at least for concentrations of titanium ranging from 0 to about 50 at. pct. More recently, Long and his collaborators have presented a tentative titanium-nickel diagram covering the titanium-rich side.' These various studies indicate that in each system three intermediate phases exist and correspond to the compositions Tia, TiX, and TiX2 (or TiX3). The purpose of this paper is to review the available information on the crystal structure of these phases and to give the results of additional X-ray diffraction studies. Previous Work A summary of the work of Wallbaum and his collaborators"-' is presented in table I. The first intermediate phase on the titanium-rich side of the three systems, with iron, cobalt, and nickel, is of the Ti2X type and has a face-centered cubic structure. Although it is stated that the unit cell contains 96 atoms: no lattice parameters are given. The second phase is centered around the compositions TiX for the three systems. The crystal structure of this phase is mentioned in a short note" as being body-centered cubic (CsCl type), but no parameters are given. The analogy between the three systems, which is perfect as far as the two phases of the type Ti2X and TiX are concerned, disappears at the titanium-poor end of the diagrams. In the system titanium- iron, TiFe2 has an hexagonal (MgZn2 type) struc-ture with the parameters given in table I. The existence of TiFe3 has also been reported8 (table I) but was questioned by other investigators2 and is also refuted by the present study. In the system titanium-cobalt, a phase corre-sponding to the composition TiCo2 has been investi-gated by Wallbaum and Witte6 who claim that the structure is cubic (MgCu2 type) for alloys slightly deficient in cobalt and hexagonal (MgNi2 type) for alloys slightly deficient in titanium. The parameters of the two phases are given in table I. In the system titanium-nickel, the nickel-rich phase corresponds to the composition TiNi3 and has been described as hexagonal7 with the parameters given in table I. The present investigation was initiated for the purpose of filling in the gaps in the knowledge con-cerning the structure of the various phases sum-marized in table I. Since the titanium used by Wallbaum and his collaborators was only 95 pct pure,' it was found desirable to redetermine the lattice parameters of the alloys prepared with a

Jan 1, 1951

By C. W. Gibbs, E. K. Parks

In 1929 the Standard Oil Company of California commenced the development of a device for obtaining temperatures and pressures in flowing and shut-in wells and of suitable running equipment for such a recorder. Although simple in principle, the recorder has required much experimental work in its development. The various problems have now been solved to such an extent that it is believed that the apparatus affords a sturdy and reliable means for obtaining information regarding depth pressures,—apparatus that may be turned over to a well gang for routine operation. As an example of the rough usage the device will withstand a recent incident may be cited. Owing to failure of the lowering line at the conclusion of a run a recorder was dropped some 6300 ft. through 2 1/2-in. tubing filled with gassy oil. The device was fished out undamaged and with the pressure record intact, although the instrument had been subjected to a pressure greater than 2300 lb. per sq. in. for some 24 hr. after impact at bottom. Description of Recorder The instrument is of the continuous recording loaded spring type (Fig. I). Temperature is not recorded continuously but is obtained by maximum recording thermometers in an auxiliary thermometer well. The entire instrument assembly, from bottom of the recorder to top of the socket, is 6 1/2 ft. long and weighs less than 25 lb. The maximum outside diameter of the recorder shell is 1 1/4in., and all attachments need be no larger. This permits lowering the device inside 2-in. tubing. The operating principle is simple. The well pressure acts upon a piston A resisted by the extension of spring B. The spring deflection is recorded by a stylus C upon paper within the recording drum D. Springs.—To improve accuracy at lower maximum well pressures five interchangeable spring assemblies are used. These have maximum pressure ranges of from 250 to 5000 lb. per sq. in. Piston diameter is the same in all cases, and each spring is designed for a deflection of about 5 in. for maximum pressure loading. A complete spring assembly there-

Jan 1, 1934