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By J. R. Low, M. Gensamer

During the course of an investigation into the drawability of automobile-body sheet steel, it became apparent that certain advantages would be possessed by a deep-drawing steel with a very low yield strength, but almost normal tensile strength, provided a reduction in yield strength could be accomplished without sacrifice of ductility and fine grain size. It would also be desirable to have this steel free from strain-aging; that is, free from the tendency for the yield point to return after it had been eliminated by straining. It was known that, wet hydrogen treatment acted to eliminate aging, but as carried out by other investigators, at relatively high temperatures, this treatment resulted in grain coarsening. It has been established by some of the experiments reported in this paper that all of these objectives can be accomplished by treatment in wet hydrogen at a low temperature, in the neighborhood of 72o°C. The time of treatment is relatively short (about 3 hr, to completion with 20-gauge sheet) if the water content of the hydrogen atmosphere is made fairly high, say aimost 30 per cent by volume. At this temperature. the grain size remains fine in the time required. After this treatment sheet reduced the usual amount by cold-rolling has a grain size of about A.S.T.M. No. 7. The yield point is completely eliminated, and the yield strength is reduced to a very low value, in the neighborhood of 15,000 lb. per sq. in. The stress-strain curve departs gradually from the straight-line elastic part after the fashion of nonferrous deep-drawing alloys. This elimination of the yield point is accompanied by a verv low indentation hardness; for example, 32 Rockwell B or even lower. There is no aging as measured by increase in the yield strength upon aging at room temperature or for 3 hr. at 200°C., after stretching about 10 per cent in tension. Tensile strength is only slightly less than the box-annealed sheet, seldom dropping much below 40,-ooo lb. per sq. in. Elongation is practically unchanged, or increased slightly. The term yield point, as here used, refers to the phenomenon of heterogeneous deformation occurring at a substantiallv constant load, observed principally in annealed low-carbon steels. If such a steel is loaded in tension, the load increases steadily with elastic strain, suddenly falls, fluctuates slightly about some constant value for a time and then begins to rise again as deformation proceeds. The maximum initial load before the sudden drop is generally called the "upper yield point"; the value of the load where deformation proceeds at a

Jan 1, 1944

By L. L. Karafiath, S. G. Vick, E. A. Nowatzki

Computer analyses of the trafficability of copper mine tailings by four different commercially available BWEs were performed. A mathematical model incorporating the tailings' Coulomb strength parameters and the vehicles' geometry and operational characteristics was used to study the vehicle terrain interaction. The computer output provides the maximum tractive force (net drawbar pull) that each BWE can develop for given tailings conditions without bnngzng about a state of plastic failure in the tailings. Estimates of sinkage are also provided. The theoretical results for the BWEs and tailings studied compare favorably with the operating experience of similar BWEs used for remining gold tailings in South Africa. This lends some confidence to the validity of the mathematical model. The results of such analyses may be wed to evaluate, on a relative basis, which of a number of different machines would perform better than others under given conditions of a tailings deposit.

Jan 1, 1982

By H. R. Deeth, C. J. Koenig

ABOUT ten years ago nepheline syenite was introduced to the ceramic industry and the material has now found application in the various branches of the industry, namely, as a vitrifying agent in white-wares and as a source of alumina and alkalies in glasses, glazes, and porcelain enamels. Spence1 described the early mining and processing developments regarding this material. Since the time of his article many research papers have appeared relating to the usage of nepheline syenite but little has been published relative to subsequent mining and processing methods. A complete indexed review of the literature was issued recently by Ohio State University.2 Since "Lakefield" nepheline syenite from Blue Mountain, Ontario (Fig I); is the only commercial ceramic-grade nepheline syenite now being marketed on this continent, discussion is limited to this operation carried on by American Nepheline Limited, Lakefield, Ont., and its subsidiary in the United States, American Nepheline Corp. at Rochester, N. Y. THE DEPOSIT Blue Mountain is a long ridge rising to an elevation of about 350 ft at its highest point above the surrounding country and extending for about six miles in a northeasterly direction across Methuen township, Peterborough County. The rock of the Blue Mountain central alkaline intrusive is fine grained, light colored and of even granitic texture. The solidified mass consists predominately of the minerals albite, nepheline and microcline in order of abundance. The average mineralogical composition for the deposit obtained by a study of 112 samples taken regularly over the whole formation is as follows:3 [VOLUMETRIC MINERAL PER CENT Albite54 Microcline20 Nepheline22 Muscovite2 Mafics2 (Biotite, hastingsite, magnetite) Total100] The mineral nepheline (or nephelite) belongs to the feldspathoid group but is lower in silica content than are the feldspars. It is a silicate of soda, potash, and alumina (NaKAl2O32SiO2). Its presence with albite (Na2O A1203 6SiO2) and microcline (K20 A12O3 6SiO2) gives the Blue Mountain deposit an alkali content of 15 pct and an alumina content of approximately 24 pct. While this huge alkaline mass is somewhat variable mineralogically, it has a uniform chemical composition. When the iron, mostly in the form of magnetite, is removed during processing, a remarkably uniform finished product is obtained. Geological surveying has disclosed many million tons of nepheline syenite in the Blue Mountain deposit. Diamond drilling in the area where mining is now being carried out indicates a block of about one million tons.

Jan 1, 1947

By M. M. Wong, D. E. Couch, G. M. Martinez

The Bureau of Mines electrowon hafnium metal with an average oxygen content of' 150 ppm at 700°C from an electrolyte containing 27 wt pct LiCl, 62 wt pct RbCl, and 11 wt pct HfC14. The average anode and cathode current efficiencies were 90 pct at anode and initial cathode current densities of 86 amp per sq ft. Haf-nium metal with an average oxygen content of 440 ppm was electrowon at 800oC from an electrolyte containing 90 wt pct KC1 and 10 wt pct HfCl4. The average anode and cathode current efficiencies were similar to those obtained in the LiCL-RbCl-HfCl, electrolyte. The chlorine gas given off at the graphite anode was vented through either a silica or a graphite tube to prevent cell corrosion. THE current method for the commercial production of high-purity hafnium is the thermal decomposition of Hfl4.1 The iodide method is not adaptable to continuous process techniques. Nettle, Hiegel, and Baker2 studied the electrorefining of hafnium from hafnium sponge containing 800 ppm oxygen. They failed to obtain hafnium with 600 ppm oxygen in their initial deposits and obtained AEC specification for oxygen only after 75 pct of the soluble hafnium had been removed from the electrolyte. Calculations using their data indicated this was approximately 4 lb of hafnium. The electrolyte was then used to produce approximately 3 lb of hafnium with a low oxygen content. However, no data are shown concerning the amount of anode material initially used or what percent of it was dissolved, therefore, results are not suitable for evaluation of a continuous operation. In general, it was not possible to consistently obtain low oxygen content metal with the electrolytes described by Nettle, Hiegel, and Baker. Wong, Hiegel, and Martinez3 investigated the electrorefining process for hafnium and showed that even by strict control of electrolyte composition only relatively low oxygen reduction could be obtained. The oxygen contained in the hafnium anode material tended to transfer to the cathode deposit and only a limited purification was possible. Both the "iodide" and the "electrorefining" processes depend upon hafnium sponge as a starting material. The sponge is normally produced by magnesium reduction of HfC14 ' and does not meet AEC specifications for hafnium metal. Since only 30 pct of the anode feed could be utilized3 in the electrorefining cells, the Bureau of Mines developed an electrowinning process. HfC14 was used as the feed material for the electro-winning process described in this report. Many of the electrolytes used in the electrorefining studies3 ap- peared to be suitable carrier-electrolytes for HfC14. However, in the initial studies on electrowinning, it was desirable to use electrolytes that had low solidus temperatures and could be operated over a wide temperature range to investigate parameters of the process. Therefore, electrolytes containing LiC1, NaC1, KC1, RbC1, CsC1, and HfC14, in various combinations were explored. EQUIPMENT Chlorinator. Hafnium carbide was chlorinated to produce HfC14 in the batch-type chlorination shown in Fig. 1. Chlorination temperatures were measured with a thermocouple placed in the center of the HfC charge. A flow meter was used to monitor the helium and chlorine. The exhaust side of the silica chlorina-tor tube was equipped with a flask for collecting organic material released during the initial heating of the HfC. The temperature of an internal heater, which extended from the HfC14 condensing flask to the hot end of the chlorinator, was adjusted to prevent the HfC14 from condensing before entering the collection flask. Helium and excess chlorine were exhausted through the lid of the collection flask to an aqueous NaOH solution. Sublimer. Initial studies were conducted using a sublimer, Fig. 2, made by placing a 13/8-in. OD nickel thimble 11 in. long, inside a 11/2-in. ID nickel bell 12 in. long, and locking it in place. This unit was loaded with HfC14 and partially immersed in the molten electrolyte for sublimation directly into the electrolyte. In another sublimer shown in Fig. 3, the HfC14 was contained in a "resin reaction flask". Quartz wool, previously heated to 600aC, secured between two nickel wire screens, was placed just above the HfC14 powder. The lid contained a vacuum outlet, a gage, an argon inlet, and an air-cooled pipe for condensing the HfC14. This sublimer was evacuated and heated. The sublimation temperature was not critical and the sublimer operated satisfactorily at all temperatures between 250" and 350°C. Electrolytic Cell. The electrolyte chamber, Fig. 4, was made of mild steel 8-in. schedule 20 pipe, 30 in. long. The exterior was metallized with a Ni-Cr alloy. The electrolytes were contained in a 16 gage nickel or iron liner with a nickel heat shield on top. The cell was heated by a resistance furnace. A 21/2-in. ID by 25 in. long air lock was connected to one port of a two-port cell cover assembly through a slide valve. The cover assembly of the air lock was electrically insulated from the cell and was equipped with a rubber sleeve that provided for the passage of the cathode lead. This allowed the cathode deposits to be removed and a new nickel cathode to be introduced without allowing air to enter the cell. A tube-rod assembly was bolted to the other port on the cell cover assembly and was sealed by a packing seal. The tube-rod assembly consists of a graphite

Jan 1, 1970

By R. L. Huntington, Frank P. Vance, George F. Russell, Robert Thompson

With the advent of higher pressures in the operation of natural-gas transmission lines, the removal of water vapor from the gas has become increasingly important in order to prevent condensation or formation of gas hydrate from slowing down or stopping the flow of gas. Intelligent design of these dehydration or gas-drying plants has been hampered through the Iack of experimental data on the water vapor content of natural gas at elevated pressures. In view of this need, this present investigation was sponsored by the Southern Natural Gas Co. in the Chemical Engineering laboratories at the University of Oklahoma Research Institute. Experimental results were obtained on the water-vapor content of natural gas up to 2000 lb. per sq. in. at atmospheric temperatures. The water content at 2000 lb. is approximately two thirds as much as it is at 1000 Ib. Deviations from the ideal gas laws vary directly with pressure and indirectly with temperature. Introduction The removal of water vapor from natural gas is an important operation in connection with the production and transportation of this commodity because: I. Liquid water accelerates internal corrosion of a pipe line. 2. Accumulation of water at low points in a pipe line reduces markedly its capacity. 3. Gas hydrates, icy snowlike growths, form readily under high pressure in the presence of the lower hydrocarbons and water, often plugging up the pipe line. In order to design dehydration plants for stripping the gas of its water content, it is essential that the engineer. have a knowledge of the saturated or equilibrium water-vapor content of the gas to be processed. With the gradual increase of operating pressures around gas-producing wells and pipe lines, it was observed that the quantity of water recovered from dehydration plants or condensed in colder lines was considerably greater than had been expected from calculated contents, based on vapor-pressure data taken from steam tables. This observation prompted a number of investigators, for instance, Laulhere,3 Dea-ton,l and Hammerschmidt2 to carry out experimental work at pressures up to 600 lb. per sq. in. in order to determine quantitatively the water content of various gases. Sage, Lacey, et al.4,5 have recognized more recently the need for such data at higher pressures, but their work was done at temperatures of 100ºF, and higher. Since hydrate formation usually, if not entirely, occurs at temperatures below 100ºF., the present investigation was confined to the . lower temperature range at pressures from 600 to 2000 lb. per sq. in. gauge.

Jan 1, 1945

By A. H. Larson, L. G. Twidwell

The influence which Au, Ag, Sb, Bi, Sn, and Cu have, both individually and collectively, on the activity coefficient of sulfur in liquid lead at 600"C zuas studied by circulating a H2S-Hz gas wlixture over a specific lead alloy until equilibrium was attained. Subsequently, the H2S concentration in the equilibrium gas mixture and sulfur concentration in the condensed phase were deterruined. The elements gold, silver, and antinzony (above 8 at. pct) increased the activity coefficient of sulfur. Bismuth had no apparent effect. Tin (above 3 at. pct) and copper decreased the coefficient. The influence of an individual element, i, on sulfur is best reported as the interaction parameter, riS, which is defined as The values o these first-order interaction zus are: ESzu = —55.0. These interaction parameters are used to predict the activity coefficient of sulfur in six fouv-component alloys and one seven-component alloy. Comparisons are made with direct experimental determinations. INTERACTIONS in dilute solution have been studied by many investigators. Most of the experimental work has been confined to solute-solvent interactions in simple binary systems and solute-solute interactions in ternary systems. Dealy and pehlke"~ have summarized the available literature on activity coefficients at infinite dilution in nonferrous binary alloys and have calculated from published data the values for interaction parameters in dilute nonferrous alloys. Interaction parameters are a convenient means of summarizing the effect of one solute species on another in a given solvent. Only a few investigators have studied interactions of the nonmetallic element sulfur in a metallic solvent. They are as follows: Rosenqvist,~ sulfur in silver; Rosenqvist and Cox,4 sulfur in steel; chipman, sulfur in alloy steels; Alcock and Richardson,% ulfur in copper alloys; Cheng and Alcock,' sulfur in iron, cobalt, and nickel; Cheng and ~lcock,' sulfur in lead and tin. The only reported work on the Pb-S system in the dilute-solution region is that of Cheng and Alcock.' Their investigation involved a study of the solubility of sulfur in liquid lead over the temperature range 500" to 680°C. The results may be summarized by the following relationship: S (dissolved in lead) + Pb(1) = PbS(s) log at. %S = -3388/T + 3.511 Experimentally, it was found that Henry's law was valid up to the solubility limit of sulfur in lead, i.e., at 600°C up to 0.43 pct. Their investigation did not include the study of sulfur in lead alloys. More accurate calculations could be made in smelting and refining systems if activity coefficients of solute species could be accurately predicted in complex solutions. One of the objectives of this study was to compare the experimental data with the values calculated from the equations derived from models for dilute solutions proposed by wagner9 and Alcock and Richardson. A temperature of 600°C was chosen as the experimental temperature to attain reasonable reaction rates and to minimize volatilization of the condensed phase. EXPERIMENTAL Materials. The Pb, Au, Ag, Sb, Bi, Sn, and Cu used for preparation of the alloys were American Smelting and Refining Co. research-grade materials. All were 99.999+ pct purity except the antimony and tin which were 99.99+ pct. The initial alloys prepared for this study consisted of twenty-one binary alloys, eleven ternary alloys, and one six-component alloy. The constituent elements were mixed for each desired alloy and were placed in a crucible machined from spectrographically pure graphite. The crucible was placed in a vycor tube which was evacuated with a vacuum pump and gettered by titanium sponge at 800°C for 8 to 12 hr. After the gettering was completed, the chamber containing the titanium was sealed and removed. The remaining sample chamber was placed in a tube furnace at 800°C for 2 hr and quenched in cold water. The final operation consisted of homogenization of the alloy for 1 to 2 weeks at a temperature just below the solidus for the individual system. The resulting master alloys were sectioned into small pieces and a random choice made for individual equilibrations. Cobalt sulfide (Cogs8) used to control the gas atmosphere in the circulation system was prepared by passing dried HzS for 24 hr over a Co-S mixture heated to 700°C in a tube furnace. This material was then mixed with cobalt metal to give a two-phase mixture which, when heated in hydrogen to a particular temperature, produced a desired H2S/H2 gas atmosphere in the circulation system. A Cu2S-Cu mixture also used in this study was prepared in a comparable manner. Apparatus for Equilibrium Measurements. The experimental technique of this study required apparatus

Jan 1, 1967

By V. H. Wilhelm

The trend initiated in January 1936, of stabilized gasoline prices, increased demand and extraordinary drilling activity, continued in California during the year 1937. Crude prices were maintained during the year at the highest level since September 1930. Wildcat activity with resultant new discoveries and development of proven acreage were greater than in any year since 1928. Many fields in California in former years have been produced at full capacity, with consequent loss of reservoir energy, but at the present time continued activity is maintained to develop adequate reserves, so that production in these fields can be taken at a rate to correspond with good operating practice. Naturally, this good operating practice will be influenced to some degree by gas outlets and, in certain instances perhaps, by oil outlets. In any event, these last two controlling features will result in favorable rather than detrimental operation. In fields producing from great depths, ultimate production will be practically limited to the flowing and compressor life of the well, since there is as yet no economical method for pumping wells below depths of approximately 7000 ft. Experience has shown, however, that such pumping difficulties will be overcome and that production secured by pumping will add some to reserves established on the flowing life of the wells. California continued to operate under voluntary curtailment, but with unlimited transfers of allowable between various fields. Even though there was at all times considerable production above the Umpire's established quota, a constantly increasing demand reduced storage during the year. This increasing demand was due mainly to the rapid rise in Pacific foreign shipments from May to September. It is questionable, however, whether this favorable condition will be maintained over a prolonged period. (See Fig. 1.) Field Discoveries The great drilling activity during the year resulted in the discovery of three new fields in the San Joaquin Valley, as well as many extensions

Jan 1, 1938

By Edward Saibel

The object of this study is to investigate the effect of prior tensile strain on the fracture stress of a metal. This is done in a theoretical manner starting from the point of view developed by the author in his thermodynamic theory of the fracture of metals. The results are compared with experimental findings and a rational interpretation is given to work that shows the variation of fracture stress with prior tensile strain. Theory op Fracture In the thermodynamic theory of the fracture of metals developed earlier,' it was shown that a critical strain energy per unit volume exists. This is characteristic of the material and may be calculated from basic thermodynamic data. When the area under the flow curve reaches this characteristic value, fracture occurs. The general criterion for fracture is expressed in the form « ± u. = JLJW/V [r] where L, is the latent heat of melting of the unit volume, AV/V is the ratio of the change in volume of the unit volume to the original unit volume on passing from the solid to the liquid state, uo is an initial energy density, and J is a conversion factor, which changes energy from heat to mechanical units. As a first approximation, it will he assumed that the stress-strain curve is the straight line that extends from the point of maximum load onward, extrapolated back to the axis of zero strain, for example, line AC of Fig. I. If the point of intersection of the straight line with the axis of zero strain is represented by v., and the slope of the straight line is p, the analytic form of the flow curve is a = (To + pd [2] and the strain energy per unit volume evaluated from Jud6 becomes (u,6 + pa2/2). When this latter term reaches the critical value JLbVIV (designated hereafter by M), it is assumed that fracture occurs. This leads to the following expression for the fracture stress: a; = V«r.2 + iMp [3] The strain at fracture may be calculated from Eqs 2 and 3. It is assumed in this paper that the initial energy density is either zero or that it may be neglected. Furthermore, the complicated states of stress and of strain existing in the necked region of the tensile specimen after "necking" has occurred will also be neglected for the present, so that average conditions will be assumed to prevail. Flow and Fracture Curves LudwigZ attributed to materials two fundamental properties: (I) a resistance to flow and (2) a resistance to fracture. He reasoned that at each instant the

Jan 1, 1948

By Edward Saibel

The object of this study is to investigate the effect of prior tensile strain on the fracture stress of a metal. This is done in a theoretical manner starting from the point of view developed by the author in his thermodynamic theory of the fracture of metals. The results are compared with experimental findings and a rational interpretation is given to work that shows the variation of fracture stress with prior tensile strain. Theory op Fracture In the thermodynamic theory of the fracture of metals developed earlier,' it was shown that a critical strain energy per unit volume exists. This is characteristic of the material and may be calculated from basic thermodynamic data. When the area under the flow curve reaches this characteristic value, fracture occurs. The general criterion for fracture is expressed in the form « ± u. = JLJW/V [r] where L, is the latent heat of melting of the unit volume, AV/V is the ratio of the change in volume of the unit volume to the original unit volume on passing from the solid to the liquid state, uo is an initial energy density, and J is a conversion factor, which changes energy from heat to mechanical units. As a first approximation, it will he assumed that the stress-strain curve is the straight line that extends from the point of maximum load onward, extrapolated back to the axis of zero strain, for example, line AC of Fig. I. If the point of intersection of the straight line with the axis of zero strain is represented by v., and the slope of the straight line is p, the analytic form of the flow curve is a = (To + pd [2] and the strain energy per unit volume evaluated from Jud6 becomes (u,6 + pa2/2). When this latter term reaches the critical value JLbVIV (designated hereafter by M), it is assumed that fracture occurs. This leads to the following expression for the fracture stress: a; = V«r.2 + iMp [3] The strain at fracture may be calculated from Eqs 2 and 3. It is assumed in this paper that the initial energy density is either zero or that it may be neglected. Furthermore, the complicated states of stress and of strain existing in the necked region of the tensile specimen after "necking" has occurred will also be neglected for the present, so that average conditions will be assumed to prevail. Flow and Fracture Curves LudwigZ attributed to materials two fundamental properties: (I) a resistance to flow and (2) a resistance to fracture. He reasoned that at each instant the

Jan 1, 1948

By Laurence Delisle, Aaron Finger

THE alloys formed by the addition of nickel to iron by convelltional metallurgical procedures show physical properties that differ widely from those of the individual metals. The effect of alloying on the mechanical properties is most pronounced in alloys containing between 15 and 25 per cent nickel. The tensile strength of an alloy containing, for example, 20 per cent nickel and 80 per cent iron (with 0.06 per cent carbon), in an annealed condition, is above 150,000 lb. per sq. in.? owing to a martensitic type of transformation, as compared with about 50,000 lb. per sq. in. for pure iron in the same condition. The object of this work was to determine whether the same beneficial alloying effect could be obtained in alloys of iron and nickel prepared by powder metallurgy technique. PROCEDURE Bars and pellets for tension and compression tests, respectively, were made. Two groups of specimens were prepared: (I) by cold-pressing the powders and sintering; (2) by cold-pressing the powders, sintering, repressing and resintering. Raw Materials Nickel powder supplied by Metals Disintegrating co., marked MD-151, was used. A typical analysis of this powder was as follows: sulphur, 0.040 per cent; copper, 0.18; iron, 0.23; manganese, 0.002; magnesium, 0.001 5 ; lead, 0.035; tin, 0.025 ; silicon, 0.08; chromium, 0.008. Electrolytic iron powder supplied by Plastic Metals Inc. was used. A representative chemical analysis for impurities other than gases, supplied by the vendor, gave the following results: carbon, 0.005 per cent; manganese, 0.002; silicon, 0.003; phosphorus, 0.001; sulphur, 0.004; nickel, 0.008. The fractions from these powders passing a 3 2 5-mesh sieve were reduced in hydrogen at 600°C. for one hour, to clean the surfaces of the particles. The reduced powders, slightly caked, were ground in a mortar and screened again through a 325- mesh sieve. Mixing The proper proportions of the powders were mixed overnight on rolls, in glass jars fitted with iron-wire baffles to break aggregates of particles that might form. Pressing All specimens were compacted on hydraulic presses. The pellets were compacted in a cylindrical die, ½ in. diameter. The ratio of thickness to the diameter of the pellets was maintained as nearly as possible at 0.9, as specifed for standard short compression pieces. The tensile bars were made by compacting 30 grams of powder. Their shape is shown in Fig. I. The compacting pressures for the pellets and the tensile bars were:

Jan 1, 1946

By Harry A. Roe

The power drag scrapers and the slackline cableway excavator have been called "long-range excavators." Broadly, their field of usefulness is restricted to work in which their long range of action permits them to operate economically, and which other, possibly more conventional, excavating units cannot do. Both of these machines dig or lift material and transport it to a remote dumping point. They combine these two functions in a single machine, nearly always in a single straight-line motion. The purpose of this paper is to examine the important features that distinguish the machines in this group from each other, as well as from other groups. The Machines The "power drag scraper" is a long-range excavating machine that employs a bottomless drag scraper operated back and forth between digging and dumping points by two haulage cables. The typical arrangement is that of Fig. 1. This is the "slusher" of the underground mine, as well as the "dragline scraper" of the sand and gravel industry, and other open-pit mining operations.

Jan 1, 1938

By Harry A. Roe

The power drag scrapers and the slackline cableway excavator have been called "long-range excavators." Broadly, their field of usefulness is restricted to work in which their long range of action permits them to operate economically, and which other, possibly more conventional, excavating units cannot do. Both of these machines dig or lift material and transport it to a remote dumping point. They combine these two functions in a single machine, nearly always in a single straight-line motion. The purpose of this paper is to examine the important features that distinguish the machines in this group from each other, as well as from other groups. The Machines The "power drag scraper" is a long-range excavating machine that employs a bottomless drag scraper operated back and forth between digging and dumping points by two haulage cables. The typical arrangement is that of Fig. 1. This is the "slusher" of the underground mine, as well as the "dragline scraper" of the sand and gravel industry, and other open-pit mining operations.

Jan 1, 1938

By C. S. Smith, E. W. Palmer

IN 1934, when Gregg and Daniloffl wrote their excellent monograph on the alloys of iron and copper, the most recent literature on the constitution of the alloys indicated a narrow single-liquid area for 20" above the liquidus with a closed liquid mis-cibility gap above this. Since that time, however, a number of investigators have confirmed the much earlier studies of Mushet2 and Stead3 who, among others in the nineteenth century, had described the true state of affairs. Liquid copper and iron are completely miscible in the absence of carbon, but small amounts of carbon cause liquid segregation. In 1934, one of the writers' mentioned evidence for the absence of liquid separation in carbon-free alloys at temperatures up to 1700°C. Two years later, Mad-docks and Claussen5 unequivocally established the absence of liquid segregation and published a revised diagram, reproduced in fig. 1. They also studied the limits of the two-liquid area in ternary alloys of iron, copper, and carbon as a function of carbon and iron content. In the same year Simpson and Bannister" and Schumacher and Souden7 described in some detail the properties of alloys containing 50 to 75 pct Cu. More recently Hodges et al.16 have developed the copper-rich alloys for use as high-strength conductors. In 1937, Iwase, Okamoto, and Ameniya8 published data on the miscibility gap in ternary alloys of iron, copper, and carbon that supported the conclusions of Maddocks and Claussen, and definitely located the two-liquid area at temperatures of 1450" and 1540°C. They also reported that additions of 1 pct Al, Ni, Pb, Sn, or Zn caused no segregation in 50 pct Cu alloys at 1540°C. The use of copper in amounts approximating 1 pct has found industrial employment to an increasing degree in both wrought and cast steels, for such steels are capable of being precipitation-hardened following normalizing, and have high yield strengths. This is summarized by Gregg and Daniloff,1 Sallitt,9 and Lorig and Adams,10 while Alexander" gives additional information on the heat treatment of copper-steel castings. Lippert12 has described Digby's two-phase steels containing copper and chromium. The work described in the present paper was done in the years 1932 to 1934, at which time much of the information was new. The excellent work subsequently done in other laboratories but more promptly published makes the present paper in part only a confirmation of what is now well known. There has not, however, been published any unified study of

Jan 1, 1951

Report of the Secretary TO THE BOARD OF DIRECTORS OF THE AMERICAN INSTITUTE OF MINING AND METALLURGICAL ENGINEERS Gentlemen:-To a Board of Directors keeping in as close touch with all of the affairs under their care as do the Board of Directors of the A. I. M. E., through their monthly meetings, a report of the year's progress is almost superfluous. To the members who read the monthly reports of. the Board Meetings and of the various activities of the Institute as published each month, a yearly report cannot carry much fresh information; yet for both it may be well, as is the custom, to glance over the field of our activities during the past year, and to make an estimate for the year to come. The beginning of 1924 was not propitious for the members of the mining profession, though tonnage production for 1923 had been high and the gross value higher than for several years. The margin of profit had been narrow, prospecting and development were limited, and many of our members were unemployed, or were working in other industries. Toward the end of the year, higher metal, prices were in sight. Old-time optimism began to grow, and it now brightens the outlook for 1925. An excellent barometer of the prosperity of the industry, and that of the Institute, for they go hand in hand, is the work of our Employment Bureau. During the past few months, the percentage of our members for whom openings have been found has been increasing to a marked extent, and many members who had fallen in arrears are placing themselves in good standing. The number of new members joining has remained about as it was in 1922 and 1923. The Directors have reason to congratulate themselves on the interest maintained during a dull period, for it is not humanly possible to take a keen interest in the technology of an industry when our hands and minds are not actively engaged in it Now, with a much brighter outlook, we can look forward to a year of increasing prosperity for the industry and for the Institute.

Jan 3, 1925

By P. W. Ramsey, E. J. Boyle, E. A. Anderson

ONLY a few zinc-rich alloys are in commercial use today, and these depend largely upon solid solution effects for their desirable properties. Typical examples are rolled alloys containing about I per cent of copper, with or without additions of elements such as magnesium,1 and die-casting alloys containing about 4 per cent of aluminum with small amounts of magnesium and sometimes copper.2 A number of elements are capable of forming alloys with zinc, which do not enter into solid solution except in limited degree. The present paper considers one such system, zinc-titanium, in which alloys having potentially useful properties in the rolled form were found. ZINC-TITANIUM SYSTEM The zinc-rich portion of the zinc-titanium diagram, as determined by standard methods in this laboratory,3 is shown in Fig. I. The portion of the diagram of significance in the present work extends from 0 to about 0.5 per cent titanium. Gebhardt4 places the eutectic at 0.45 per cent, but the evidence in favor of the composition given in Fig. I is considerable. The solid solubility of titanium in zinc is very low indeed and possibly places these alloys in a somewhat different category from the commercial alloys previously mentioned. ALLOY PREPARATION All of the alloys used in this work were prepared with titanium metal of 98.9 per cent purity. In most cases high-purity zinc (99.99 per cent) was used but sufficient work was done later to show that zinc of about high-grade composition would yield approximately equal results. Best practice in alloy manufacture seemed to be to prepare a zinc-titanium hardener by adding about 4 per cent of titanium metal to molten zinc and holding under a boric acid cover, with frequent stirrings, at 750°C. until the titanium had dissolved. The desired titanium content could readily be obtained in the final alloy by adding the calculated amount of this hardener. The alloys proved to be quite stable in composition, unless overheated, and, with reasonable temperature control, required no cover or flux to prevent loss of titanium content by oxidation. HOT-ROLLING TESTS Three alloys containing, by analysis, 0.05, 0.12, and 0.23 per cent titanium were selected for preliminary study. Slab cross sections revealed a marked grain refinement* (Fig. 2) in the two alloys of highest titanium content. Cast unalloyed zinc has a columnar grain structure similar to that shown for the alloy of lowest titanium content but without the scatter of small equiaxed grains at the center.

Jan 1, 1944

By d&apos, L. Berenbaum, F. Heurle, R. Rosenberg

The structure of aluminum films obtained by evaporation was studied by electron microscopy, mostly by replica techniques and X-ray diffraction. The resistivities and stress conditions of the films were also determined. Film properties were studied as a function of source selection, substrate type, residual pressures of oxygen and water vapor, substrate temperature, and rate of growth. The formation of abnormal localized growths and whiskers resulting from annealing treatment subsequent to deposition was investigated. Films deposited onto single-crystal substrates were found to be epitaxially 0riented; for such films, relative orientations between films and substrates were determined. ALTHOUGH wide use has been made of evaporated aluminum films for the formation of conducting lines on semiconductor devices, relatively little has been reported concerning the structural characteristics of such films.1"9 The purpose of this study was to obtain an overall view of the dependence of these characteristics on film deposition and subsequent annealing conditions, which were similar to those used in silicon planar technology. Accordingly, most of this study was carried out using oxidized and bare silicon wafers as substrates, although some work was also done using alkali halide, magnesium oxide, and mica substrates. However, the main concern remained pragmatic. Emphasis was given to the study of the effects of deposition and annealing conditions on film characteristics such as structure, resistivity, and stress. I) EXPERIMENTAL PROCEDURES The films which were investigated in this study were deposited in 18-in.-diam glass chambers which were connected to the usual type of trapped diffusion pumps filled with silicon oil. Through the use of liquid-nitrogen-cooled Meisner traps and titanium sublimation pumps placed inside the deposition chambers, the pressure could be lowered to the lower portion of the 10- I Torr range and little increase in pressure would occur during the deposition cycle. Unless described otherwise, the substrates were 1-in.-diam p-type silicon wafers having a resistivity of 10 ohm-cm. The wafers were oxidized in wet oxygen at 975°C followed by a short dry-oxygen exposure at the same tempertture to a total oxide thickness of approximately 6000A. The wafers, backed by a layer of gallium, were mounted onto molybdenum discs brazed to a copper block.10 The latter was heated by imbedded commercial cartridge heaters. The substrate temperature could be maintained to within +10°C of a prescribed temperature during film deposition. The search for a satisfactory source for the controlled evaporation of aluminum has led to the use of 1-in.-diam crucibles" machined from rods of a commercially available, refractory composite* of Bn and

Jan 1, 1969

By Sherwin F. Kelly

SINCE we used Chief Buehler's name last year to give our annual report a semblance of respectability, we can follow the good precedent thus established by telling of the work his Missouri State organization has been carrying on, as reported by H. S. McQueen. Considerable value is set upon their magrletorneter working which has covered over 13,000 sq. mi.), for the indications it gives of the major structural features of the region. Numerous geological problems have been tackled Ly resistivity techniques, among which are the locating and outlining of filled sink deposits of sulphides, of iron ore, and of fire clay; tracing of faults and solution channels; mapping of the preglacial structural pattern; measurement of depth of overburden; and

Jan 1, 1937

Executive Committee. ROBERT H. RICHARDS, Chairman. ALBERT SAUVEUR, Vice-Chairman. TIMOTHY W. SPRAGUE. HENRY A. WENTWORTH. AUGUSTUS H. EUSTIS, Secretary, 131 State St., Boston, Mass. The twelfth meeting of the Boston Section was held at the Engineers' Club, 2 Commonwealth Ave., Boston, on Monday evening, May 5, 1913, fifteen members and three guests being present. The meeting was called to order by Vice-Chairman Albert Sauveur, who introduced the speaker of the evening, Utley Wedge, of Ardmore, Pa. Mr. Wedge read his paper on the chloridizing roasting of copper ores, which he illustrated with a stereopticon, and which will be published in full by the Institute. After Mr. Wedge had closed his paper, which was received with great interest by all the members, the following discussion took place: Professor Hofman said that iron was formerly thought to ho essential to the Henderson process, but that it is not absolutely essential. Mr.Wedge said that, as far as he. knew, the presence of some sulphates was an abso¬lute necessity, and that line ores can be worked satisfactorily, although lime has an effect on the subsequent leaching. He added that the low fuel consumption of the latest Wedge furnace is a result of direct application of the combustion gases to the ore. Ten per cent. of fuel was needed with the muffle furnace. By direct firing he has been able to reduce the fuel needed to from 2 to 4 per cent. In the latest types of furnaces the gases from the upper hearth are not used. There is doubtless some temperature at which the loss. from copper chloride volatilization becomes serious, but in practice on Rio Tinto ores troublesome losses are not experienced. The copper apparently does not become volatile at. the temperatures where we would expect that it would. There are doubtless ores in which there would be serious danger from losses from this source. The latest furnaces do not use the high temperatures that were needed in the former single-hearth Wedge furnaces.

Jan 7, 1913

By Arnulf Muan, Klaus Schwerdtfeger

Equilibrium ratios C02/C0 of a gas phase coexisting with selected phase assemblages of the system Fe-Mn-0 have been determined in the temperature range 1000" to 1300°C. The oxygen pressure for the "hfnO" +hfn30, equilibrium and for the "(Fe,hTn)O" + (Fe,Mnh 0* equilibrium at high manganese contents has been determined by electromotive force measurements using stabilized zirconia as a solid electrolyte. The notstoichometry 01' "hTnO" and of "(Fe, iM1z)O" solid solutions has been determined by ther-mog-/avi?netry and by wet-chemical analysis. The data obtained are used to derive activity-composition relations in "(Fe,hfn)O" and (Fe,Mn),O4 solid solutions. WUSTITE "FeO" and manganosite "MnO" form a continuous series of solid solution at high temperatures,' and so do magnetite Fe304 and the high-temperature, cubic modification of Mn304 (Ref. 2) (high hausmannite, -1170). The oxides "FeO" and "MnO" are cation-deficient phases.495 The nonstoi-chiometry of "(Fe,Mn)O" solid solutions has been studied by Engell and ~ohl' at two selected C02/C0 ratios at 1250°C. The two oxide end members of the spinel solid solution, FesO4 and Mn,04, however, are known to be close to stoichiometric under the experimental conditions used in the present investigation.''' The oxygen pressures of "(Fe,Mn)07' solid solutions in equilibrium with iron have been determined by Schenck and coworkers,8 by Foster and welch," and by ~n~e1l.l' The two former groups equilibrated the condensed phases in C02-CO atmospheres of lmown compositions, whereas Engell" used a galvanic cell with stabilized zirconia as a solid electrolyte. The results of these investigators are not in good agreement. Activities of FeO in manganowiistite as calculated from the results of Foster and Welch show ideal behavior, those of Engell yield a pronounced positive deviation, and those of Schenck et 01. show a moderate positive deviation from ideality. In the present work oxygen pressures for the iron + manganowiistite and manganowustite + spinel equilibria and the nonstoichiometry of manganowiistites have been measured. The data were used to calculate activities in the manganowiistite and spinel solid solutions. EXPERIMENTAL METHODS The COz/CO ratios at which manganowustite and iron are in equilibrium were determined by thermo-gravimetric and quenching methods. Experimental details are described in a previous publication.'2 In the thermogravimetric technique, incipient reduction of manganowiistite pellets to metallic iron was observed as a break in the weight vs log COZ/CO curve. In the quenching technique, manganowiistite samples were partially reduced to metallic iron, or the metallic iron of manganowustite + metallic iron mixtures was partially oxidized to manganowustite, in atmospheres of constant C02/CO ratios. After quenching the composition of the oxide phase was determined by X-ray lattice parameter measurements and comparison with a standard curve obtained from oxide solid solutions of known compositions. The nonstoichiometry of "MnO" and "(Fe,Mn)07' solid solutions was determined by chemical analysis of samples equilibrated in C02-CO atmospheres and quenched to room temperature, as well as thermo-gravimetrically by reducing (Fe,Mn),04 or Mn304 to manganowiistite or manganosite. The equilibrium between manganowiistite and (Fe,Mn),04 was measured thermogravimetrically by reducing (Fe,Mn),04 solid solutions having composition in the range of %„ l(NFe +NM) from 0 to 0.63. No experiments could be performed with this technique at higher manganese contents, because the equilibrium C02/C0 ratios are too large for accurate control. An additional difficulty arises at the higher manganese contents due to the strong increase in oxygen content of the manganowustite phase with increasing log Py near the manganowiistite-spinel boundary. Consequently a sharp break in the weight loss vs log C02/CO curve cannot be observed at the phase boundary. At high manganese contents of the manganowiistite, e.g., (NMn/(NF~ + NMn) > 0.9, electromotive force measurements with stabilized zirconia as a solid electrolyte were made to determine the equilibrium oxygen partial pressure. Experimental details are described in a previous paper.* Mixtures of "(Fe,Mn)O" and (Fe,Mn),04 were pressed to pellets, and the oxygen pressure of the equilibrated samples was compared to that of Ni + NiO mixtures in the cell The composition of the manganowiistite in the equilibrated two-phase mixture was determined by lattice parameter measurements and comparison with known standards. The oxygen pressure for the Ni + NiO equilibrium was taken from available data.l3~l4 No reliable results were obtained with the electromotive force technique on iron-rich oxides. The electromotive force drifted strongly with time in this composition range. An additional difficulty arises from the partial de-

Jan 1, 1968

By H. Cecil Spicer

The results described in this article are based on field work conducted during the periods APril-May, 1939, and MaY-JulY, 1940. The United States Potash CO. is mining potash on Government land under a permit from the Department of the Interior and the geophysical investigation mas completed under a cooperative arrangemerit made between that company and the Conservation Branch of the Geological Survey. The writer, a member of the Section of Chemistry and Physics of the Geologic Branch, was assigned to this investigation. Four definite objectives were in mind for the geophysical work in the studies over the salt deposits. The first was to determine the measure of success that could be attained in this type of work with the resistivity methods that were to be employed. These methods had been introduced into the work of the Conservation Branch by Benjamin E. Jones for the investigation of dam sites, and have been used under his direction by the author for such work. If the method proved to be applicable, an l was to be made to contour the top of the salt beds and also the other formation boundaries known to be present in this area. Salt-water aquifers were to be studied in an effort to determine their boundaries, and an attempt was to be made to delineate the potash-bearing beds. Others have made, and reported, resistivity studies over saliferous deposits in different areas. Friedell and Messrs. Schlumberger2 reported geophysical work performed in the disrovery of the salt domes of Alsace; Carrette and Kelly3 described the geology of the same area. Leonardon and Kelly4 published a resistivity curve obtained over the Hettenschlag dome, and a further discussion of this same area was given by the Messrs. Schlum-berger5 in a communication. Messrs. Alty6 described studies 0" salt deposits in which the sing[e-probe method was used. Sinerez7 mentions that electrical methods were tried over salt deposits in Spain. Geoffrey and Charrin8 show a resistivity curve obtained over marl, gypsiferous marl and salt which is similar to that obtained over the New Mexico salt deposits. Kelly9 reported resistivity work performetl with the ground comparator of Zuschlag over the salt deposits near Syracuse, N. Y., where the Salina formation is at a depth of 700 to 800 ft. Some structural studies on the potash basin of Alsace are described by Poldini.10 Another single-probe resistivity study, made over salt deposits in New Mexico, is briefly described by Heiland,ll through the courtesy of Harry Aurand, of the Midwest Refining CO.

Jan 1, 1942