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By W. L. Phillips

Nickel alloys containing approximately 0.5, 2.0, and 6.0 at. pct of Os, Pd, Ru, and Rh were Prepared by vacuum melting. Tension tests were carried out at 25°, 500°, 800°, and 1000°C; stress-rupture tests were carried out at 650° and 800°C. The room- and elevated-temperature tensile strength, as well as the stress-rupture life, increased for the same atomic percent in the order palladium, rhodium, ruthenium, osmium. The ductility decreased with increasing concentration or temperature for a given concentration. The results are discussed in terms of solid-solution theory. BOTH solid-solution strengthening and weakening have been observed in alloys. The simple rules which have been suggested to explain alloy strengthening are subject to several exceptions and deviations based on atom size and valency effects. The purpose of the present investigation was to extend the knowledge of the effect of solid-solution alloying on the mechanical properties of several Ni-Pt group metal alloys at room and elevated temperatures. The platinum group metals, osmium, ruthenium, rhodium, and palladium were chosen as the solute elements because of their different valencies and atom sizes. Nickel was chosen as the base material because of the large amount of previous literature available on nickel alloys. EXPERIMENTAL PROCEDURE Grade A Carbonyl nickel powder having the following composition: C, 0.07 pct; Fe, 0.013 pct; Mn, 0.0005 pct; Si, 0.016 pct; Mg, 0.0003 pct; S, 0.003 pct, was purchased from the International Nickel Co. The platinum-group metal powders were purchased from A. D. Mackay Co. The powders were weighed, cone-blended for 4 hr, and vacuum-melted into 1-in.-diam billets, approximately 2 in. long. The ingots were homogenized for 5 hr at 1800°F before being extruded into 1/4-in. rods at 2100°F. The alloy compositions are shown in Table I. Typical impurity values were not significantly different than that of the as-received nickel. All alloys were single phase. The lattice parameter of each alloy after the heat treatment described below is also included in Table I. Each alloy was annealed at 2200°F for 1 hr and air-quenched to comparable grain sizes (ASTM G.S. No. 4-5). The rods were then machined into test samples 0.160-in. diam and 0.750-in. gage length. Tension testing was carried out in an In-stron tension-testing machine at a strain rate of 0.02 in. per in. per min. An extensometer was used to determine the room-temperature yield stress. Stress-rupture testing was carried out in an Arc Weld stress-rupture unit. All testing was performed in air. EXPERIMENTAL RESULTS A) Room-Temperature Mechanical Properties. The 0.2 pct yield stress, ultimate tensile strength, and elongation for all alloys tested at room temperature are plotted as a function of atomic percent solute element in Fig. 1. The ultimate tensile strength for the same atomic percent increases in the order palladium, rhodium, ruthenium, osmium. The yield strength at low concentrations, -0.5 at. pct, increases in the order osmium, palladium, ruthenium, rhodium. At higher concentrations, 3.0 and 10.0 pct, the yield strength increases in the same order as the tensile strength. Both yield strength and tensile strength increase rapidly ini-

Jan 1, 1964

By C. G. Dunn

MANY investigations have been made concerning the nature of plastic deformation and recrystallization of metals either in the form of polycrystalline materials or in the form of single crystals. However, similar work on strip materials composed of large grains as thick as the strip and having a high degree of preferred crystal orientation has not been carried out extensively. Such materials are ideal not only for studying changes in single crystals under conditions where neighboring grains exert their influences but also for obtaining the, complete change in orientation of a grain or group of grains during the course of plastic deformation and subsequent recrystallization. It is well known that first-order twins in the form of Neumann bands may be produced during the plastic deformation of ferrite crystals, particularly silicon ferrite crystals.1-3 Furthermore, it is believe that high-stress regions exist in the vicinity of these bands4a and it has been said that these banded regions would be active in recrystallization processes.5 Evidence to that effect in silicon ferrite had already been presented with photomicrographs showing recrystallization among Neumann bands during the early stages of recrystallization.5,6 Similar evidence has been published for nonferrous metals.5 Merging of fine parallel deformation bands during annealing to form twin bands of ordinary appearance in alpha brass has been offered not only as evidence of an active role being played by mechanical twins but also as evidence that such twins existed prior to recrystallization.5 Proof that such new structures are actually first-order twins, or even twins at all, must be considered inadequate except for those cases where X-ray or optical data have been obtained to confirm the necessary orientation relationship.7,8 A. B. Greninger has obtained excellent iliustrations of annealing twins in alpha irons Since his material was previously deformed by sharp hammering, a process that generally induces Neumann bands, the existence of twins following annealing might suggest that they grew from mechanical twins. In connection with transformation twins in alpha iron, Greninger reported that grains containing. three twin orientations occurred rarely and none occurred with three sets of well-developed bands.9 The work at the Pittsfield Works Laboratory on silicon ferrite in the form of large-grained strip steel deformed a small amount and annealed to partially recrystallize the grains indicates that the deformation and recrystallization processes that lead to annealing twins involve more complex processes than the formation of Neumann bands and the growth of such bands. Some groups of annealing twins are obtained which contain not only three well-developed twin structures, but also contain more than one order of twins. It is also shown, in one case, that an interrelated group of twins did not arise within one single parent grain and, furthermore, orientations of grains in the group

Jan 1, 1944

By C. A. Heiland, Tripp R. M., Dart Wantland

This paper serves to illustrate the application of geophysics to a virtually abandoned mine properly, an application that led to the discovery of an ore body and thus afforded an Opportunity to cOmpare subsequent geologic findings with geophysical data. The work herein described represents, however: more than mere ''case history." It demonstrates that it is possible to obtain satisfactory results by simple means and relatively inexpericnced personnel. The geophysical surveys were made by students as a part of their field assignments in the course of their regular training, and were supervised by Dart Wantland, J. E. Hawkins and R. Maurice 'Tripp. In the course of several seasons an appreciable amount of material was accumulated, which gave graduate students an opportunity for special studies. In this connection, the contributions by L. Massé, R. C. Hyslop, and J. E. Hawkins deserve special mention. The property owners cooperated wholeheartedly in the work, and special thanks are due messrs. J. F. Johnson and S. E. Zelenkov, of the American Smelting and Refining Co., for their interest and for permission to utilize the results of their development work for this publication. Location and Geology The Malachite mine is situated on the northcrn slope of Bear Creek Canyon, 4 miles northeast of Evergreen, I½ miles northwest of Idledale, and 4% miles west northwest of Morrison, in Jefferson County, Colorado. The location (Fig. I) is north of the center of set. 30, T. 45, R. 70 W., at an elevation of about 7500 ft, above sea level, Near the mine the terrain slopes rather uniformly southward at an angle of about 180 pigs. 3 and 7). The geology of the Malachite mine area has been described by J, underhill,' W, Lindgren,2 and J. Boyd.3,4 A map showing surface outcrops and mine workings appears in Fig, 2. the Malachite mine is in an amphibolite belt enclosed in gneisses and schists of the Idaho-Springs formation (probably early Algonkian age). The highly contorted beds are nearly vertical and strike slightly north of west. A series of granite-pegmatite dikes have been intruded almost at right angles into the gneisses and schists and doubtedless are postmineral. While most of the formations are exposed at the surface, a part of the 'lope is covered by slide rock and float, and in the eastern portion by alluvium and creek fill. A quartz-diorite dike cuts through the amphibolite schists at a small angle with nearly vertical dip. The copper sulphides, developed in this dike by magmatic segregation, occur in lenticular form. As far as the mine workings have revealed, the ore lenses are often discontinuous in depth and

Jan 1, 1946

By Tripp R. M., C. A. Heiland, Dart Wantland

This paper serves to illustrate the application of geophysics to a virtually abandoned mine properly, an application that led to the discovery of an ore body and thus afforded an Opportunity to cOmpare subsequent geologic findings with geophysical data. The work herein described represents, however: more than mere ''case history." It demonstrates that it is possible to obtain satisfactory results by simple means and relatively inexpericnced personnel. The geophysical surveys were made by students as a part of their field assignments in the course of their regular training, and were supervised by Dart Wantland, J. E. Hawkins and R. Maurice 'Tripp. In the course of several seasons an appreciable amount of material was accumulated, which gave graduate students an opportunity for special studies. In this connection, the contributions by L. Massé, R. C. Hyslop, and J. E. Hawkins deserve special mention. The property owners cooperated wholeheartedly in the work, and special thanks are due messrs. J. F. Johnson and S. E. Zelenkov, of the American Smelting and Refining Co., for their interest and for permission to utilize the results of their development work for this publication. Location and Geology The Malachite mine is situated on the northcrn slope of Bear Creek Canyon, 4 miles northeast of Evergreen, I½ miles northwest of Idledale, and 4% miles west northwest of Morrison, in Jefferson County, Colorado. The location (Fig. I) is north of the center of set. 30, T. 45, R. 70 W., at an elevation of about 7500 ft, above sea level, Near the mine the terrain slopes rather uniformly southward at an angle of about 180 pigs. 3 and 7). The geology of the Malachite mine area has been described by J, underhill,' W, Lindgren,2 and J. Boyd.3,4 A map showing surface outcrops and mine workings appears in Fig, 2. the Malachite mine is in an amphibolite belt enclosed in gneisses and schists of the Idaho-Springs formation (probably early Algonkian age). The highly contorted beds are nearly vertical and strike slightly north of west. A series of granite-pegmatite dikes have been intruded almost at right angles into the gneisses and schists and doubtedless are postmineral. While most of the formations are exposed at the surface, a part of the 'lope is covered by slide rock and float, and in the eastern portion by alluvium and creek fill. A quartz-diorite dike cuts through the amphibolite schists at a small angle with nearly vertical dip. The copper sulphides, developed in this dike by magmatic segregation, occur in lenticular form. As far as the mine workings have revealed, the ore lenses are often discontinuous in depth and

Jan 1, 1946

The Gooseberry Mine is located 38 krn (24 miles) by road east of Reno, 13 km (8 miles) south of Interstate 80. The mine was originally discovered in 1906 and remained in the control of the Martin family of Fresno, who worked the-property with Mexican ranch hands for 68 years. Westcoast took over the property in 1976 from Apco Oil Corporation. During the time the Martins operated the mine, a 305 m (1,000 ft) inclined shaft was sunk with drifts developed on eight levels exceeding a total of 3,000 m (9,000 ft) in length. It is interesting to note that for over one -half century all development ore was stockpiled. West- coast, the United States mining subsidiary of Home Oil Company Ltd., Calgary, Alberta, completed sinking another vertical shaft to the 396 m (1,300 ft) level. Development work between 122 m and 305 m (400 ft and 1,000 ft) levels has proved the existence of a fine ore body over 300 m (1,000 ft) long. The silver-gold ore grade is fairly consistent in the vertical section, but copper, lead and zinc may show slight increases with depth. Average width of the ore bearing portion of the vein is 2.5 m (8.3 ft). Stoping is by cut-and-fill method. Average silver values within the ore zone have increased from the 152 m (500 ft) level to the 305 m (1,000 ft) level, although the gold values do show some decrease. It is not possible for the geological staff to predict the depth of the ore. However, several years of ore reserves have been proved in the existing mining areas. Important ore minerals are argentite, native gold, and electrum. Trace amounts of galena, chalcopyrite, and sphalerite are associated with the precious metal mineralization. The vein is mainly composed of calcite and quartz. Mine-run underground ore is dumped from the hoisting skip into a coarse ore bin followed by a jaw crusher, an impact crusher, and a 600 mt (650 st) fine ore bin. The mill has a capacity of 317 mt per day (350 st per day). Two-stage grinding is done by a rod mill followed by cyclones with the underflow sent to a ball mill in closed circuit with the cyclones. Cyclone overflow after conditioning receives a primary float in four 1.7 cu m (30 cu ft) cells and a second stage of conditioning ahead of 24 0.8 cu m (30 cu ft) secondary flotation cells. No cleaning stages are used. Flotation tailings are cycloned for a sand-slime separation with the sands used as underground stope fill and the slime portion to tailing dam storage.

Jan 1, 1981

By Ursula E. Wolff

Il.lechanica1 twins have been observed in brigsten single crystals of a variety of axial orientations defornzed at room temperature in tension or bending. The twins formed near the final fracture and were up to 3 p thick. The twinning plane was always of the type (113). Twinning at room ternperature occurred only after considerable prior slip. Twins usually preceded fracture and nucleated cracks. The crack surfaces often alternated between a (001) plane and the twin interfaces. Secondary twins could also nucleate from cracks. In the absence of twinning tensile samples failed by shear; twinned samples failed by cleavage. On the assumption that observed sudden load drops in the stress-strain curves are associated with twinning, a critical resolved stress for twinning of 60, 000 to 65, 000 psi was calculated. MeCHANICAL twinning has been observed in iron and iron alloys at low temperature by a number of investigators.'-7 Similarly, for high-purity tungsten, twinning has been reported for deformation temperatures below 211°K.8-10 In W-Re and Mo-Re alloys, 20 pct Re was determined as the lower limit for twin formation at room temperature." Since the twins are generally very narrow, they are usually identified only by etching techniques. The expected (112) habit plane has always been confirmed by angular analysis of the surface traces. Recently, however, a complete identification by X-ray analysis has been performed on twins in a Mo-35 pct Re alloy.12 During an investigation of the deformation charac- teristics of tungsten single crystals, twins were revealed in tensile and bend samples deformed at room temperature. This paper deals with the conditions for such twinning and the relation of twinning to fracture. EXPERIMENTAL PROCEDURE Tungsten single crystals, 1/8 in. in diam, of a variety of axial orientations were grown from un-doped material by four-pass electron-beam zone melting. A representative analysis is given in the following table: From these crqstals, tensile samples with 1 in. gage lengths were made by surface grinding, leaving shoulders for gripping. The diameter after grinding was 0.082 in. The distorted surface layer was then removed by ele1:trolytic polishing which reduced the diameter of the gage length to 0.080 in. Tensile tests were carried out at room temperature in an Instron machine under two different sets of conditions: a) Rigid mounting; strain rate 0.02 in. per in. per min. b) Gimbal mounting; strain rate 0.002 in. per in. per min up to a total strain of approximately 0.2 pct, then 0.01 in. per in. per min to fracture. Stress axis and growth direction coincided in all samples and are subsequently called orientation.

Jan 1, 1962

By Eric Kula, Åke Josefsson

L. J. Dijkstra and R. Sladek, (Ontario Research Foundation, Toronto, and Institute for the Study of Metals, Chicago, respectively)—This interesting paper confirms some results obtained some years ago in collaboration with Fast: namely the broadening of the nitrogen peak by the presence of small amounts of manganese. Later on a more extensive study of this effect was made at the Institute for the Study of Metals at Chicago. As the work has not yet been submitted for publication we wish to mention here briefly some of the results. The effect of about 0.5 atomic pct manganese, chromium, molybdenum, or vanadium on the nitrogen-peak in iron was examined. The broadening found previously in the case of manganese was even found to be more pronounced for chromium. In the case of molybdenum and vanadium a double peak was observed which seemed to justify the idea that in all cases mainly two relaxation times were involved: namely, the normal relaxation time as found in pure iron and a second relaxation time related to the existence of abnormal interstitial lattice sites introduced by the foreign metallic element. The analysis showed that for the normal nitrogen-peak as a reference at 22°C the abnormal peak was found at about 32°, 47°, 75°, and 87°C in the case of manganese, chromium, molybdenum, and vanadium, respestively. In the manganese alloy the free energy difference for a nitrogen-atom at an abnormal and a normal lattice site was estimated at 2800 cal per mol. This means that for temperatures above 100°C the solid solubility and overall diffusion rate of nitrogen is not much affected by additions of 0.5 pct Mn. We believe that the difference in rate of precipitation of nitrogen in pure iron and the manganese alloy is mainly a question of the number of potential nuclei available in the different steels. In studying the effect of these alloying elements on precipitation of nitrogen, a distinction must be made between the para reaction and ortho reaction, using terminology introduced by Hultgren.7 The ortho reaction in which the alloying metallic element participates in the diffusion under formation of nitrides occurs at high temperatures such as 600°C. The para reaction in which the alloying metallic element does not diffuse and in which the nitride inherits its alloy content from the matrix occurs at lower temperatures. To prevent the ortho reaction the alloys have to be quenched rapidly from the phase. It is not surprising that the authors find that the height of the peak indicates a lower nitrogen content than chemical analysis. In the first place the peak is not a single relaxation peak and secondly, the steels were not quenched from the phase after the nitrogen was introduced at 580 °C.

Jan 1, 1953

By V. C. Perini

The North Central Texas district as herein defined includes the counties of Brown, Callahan, Coleman, Comanche, Coryell, Eastland, Erath, Fisher, Hamilton, Haskell, Hood, Jones, Lampasas, Mills, Nolan, Palo Pinto, Parker, San Saba, Shackelford, Stephens, Stonewall, Summer-ville, Taylor, Throckmorton and Wise. These counties as listed are the counties of District 7B, State Railroad Commission. In the new designation of districts for the Transactions, the North Central Texas district includes most, but not all, of the counties of the previously classified West Central Texas district. This district covers the south central crest and the west flank of the Bend flexure north of the Llano uplift. The west flank of the Bend flexure is on the east boundary of the Permian Basin of West Texas. The greater part of the oil and gas produced in this district has been from Pennsylvanian strata. Some oil and gas has been produced from the lower Permian (by the latest, selection of the Pennsyl-vanian-Permian boundary) and minor amounts from the Mississippian and Ordovician sediments. Increasingly important quantities of oil and gas are to be expected from the older sediments by deeper development in proven fields and by new discoveries. Most of the oil and gas in the district has accumulated in localized, well-defined structural traps in limestone and sandstone reservoirs and in traps due to stratigraphic changes in sedimentation, mainly porosity traps in limestone and sandstone lenses, both usually associated with some structural feature. These features are found by surface and subsurface geological structural mapping, by core drilling and by geophysical surveying. Geochemical methods are also the basis for some wildcatting. The demand for sweet crude oil from this district is firm for local and national consumption, but the market price for the oil remains practically the same as in 1941. The price is not adequate to meet the requirements of the average independent operator with the continued advance in production, tievelopment and wildcatting costs. Stripper wells are being plugged daily and should be jealously saved for the future local and national reserves, especially in view of the fact that new discoveries of commercially important oil and gas reserves are not keeping pace with consumption. An expected economic disruption attendant upon the national war effort has arisen and continues in the future outlook for this district. The lack and delay of securing replacement parts for almost all oil-field equipment has handicapped and delayed operations and has decreased efficiency in wildcatting, development and production. Sufficient experienced drilling, scientific and office personnel is lacking because of inductions in the armed forces and migration to war industries during the period before manpower conservation became effective. The office personnel of the average oil and gas producer continues to be swamped by the increasing demands for reports by state and federal bureaus. An average of IQ days

Jan 1, 1944

By V. C. Perini

The North Central Texas district as herein defined includes the counties of Brown, Callahan, Coleman, Comanche, Coryell, Eastland, Erath, Fisher, Hamilton, Haskell, Hood, Jones, Lampasas, Mills, Nolan, Palo Pinto, Parker, San Saba, Shackelford, Stephens, Stonewall, Summer-ville, Taylor, Throckmorton and Wise. These counties as listed are the counties of District 7B, State Railroad Commission. In the new designation of districts for the Transactions, the North Central Texas district includes most, but not all, of the counties of the previously classified West Central Texas district. This district covers the south central crest and the west flank of the Bend flexure north of the Llano uplift. The west flank of the Bend flexure is on the east boundary of the Permian Basin of West Texas. The greater part of the oil and gas produced in this district has been from Pennsylvanian strata. Some oil and gas has been produced from the lower Permian (by the latest, selection of the Pennsyl-vanian-Permian boundary) and minor amounts from the Mississippian and Ordovician sediments. Increasingly important quantities of oil and gas are to be expected from the older sediments by deeper development in proven fields and by new discoveries. Most of the oil and gas in the district has accumulated in localized, well-defined structural traps in limestone and sandstone reservoirs and in traps due to stratigraphic changes in sedimentation, mainly porosity traps in limestone and sandstone lenses, both usually associated with some structural feature. These features are found by surface and subsurface geological structural mapping, by core drilling and by geophysical surveying. Geochemical methods are also the basis for some wildcatting. The demand for sweet crude oil from this district is firm for local and national consumption, but the market price for the oil remains practically the same as in 1941. The price is not adequate to meet the requirements of the average independent operator with the continued advance in production, tievelopment and wildcatting costs. Stripper wells are being plugged daily and should be jealously saved for the future local and national reserves, especially in view of the fact that new discoveries of commercially important oil and gas reserves are not keeping pace with consumption. An expected economic disruption attendant upon the national war effort has arisen and continues in the future outlook for this district. The lack and delay of securing replacement parts for almost all oil-field equipment has handicapped and delayed operations and has decreased efficiency in wildcatting, development and production. Sufficient experienced drilling, scientific and office personnel is lacking because of inductions in the armed forces and migration to war industries during the period before manpower conservation became effective. The office personnel of the average oil and gas producer continues to be swamped by the increasing demands for reports by state and federal bureaus. An average of IQ days

Jan 1, 1944

By B. N. Bose, M. F. Hawk

SINCE Davenport and Bain' introduced the isothermal transformation technique for the study of austenite decomposition in steels, a new field of investigation has opened up. Extensive research has been carried out on many different steels, but relatively little work has been done on eutectoid transformations in analogous alloy systems. The researches of Smith and Lindlief,² Mack,³ and Klier and Grymko²0 on the beta-phase transformation in copper-aluminum alloys, of Hibbard, Eichelrnan, and Saunders4 and Smith5 on the kappa-phase transformation in copper-silicon alloys, of Chaudron and Forester6 on the decomposition of "FeO," and of Wasserman7 on similarities between the iron-carbon, copper-aluminum, copper-tin, and copper-beryllium systems essentially comprise the field. The iron-nitrogen system, in view of its remarkable similarity to the iron-carbon system, is particularly attractive for the study of eutectoid decomposition. The present investigation is concerned with the study of isothermal transformation, proceeding by the familiar nucleation and growth processes, and of martensitic transformation characteristics of pure iron-nitrogen alloys. The kinetics of transformation and the morphology of the transformation products have been investigated, for these must be the factors determining the properties and behavior of the final product. The Iron-Nitrogen System he binary iron-nitrogen phase diagram has been a matter of considerable disagreement among vari01.1s investigators. However, the phase diagram according to Eisenhut and Kaupp8 and Lehrer10 is now considered essentially correct as reproduced in fig. 1. The important values, 2.35 pct nitrogen and 591°C, for the co-ordinates of the eutectoid point (obtained from this diagram and used in the re- search to be described) were confirmed in a concurrent study of Paranjpe, Cohen, Bever and Floe." The eutectoid decomposition involves the transformation of the ? face-centered cubic interstitial solid solution of nitrogen in iron to the a body-centered cubic interstitial solid solution of nitrogen in iron and the ?' nitride of iron. This nitride is essentially the compound Fe,N; it also possesses a face-centered cubic lattice but a considerably larger one than the ?; the nitrogen atoms in ?' are arranged in an ordered way in the centers of the unit cubes.8,10,11 A martensitic structure has also been reported8,12 in iron-nitrogen alloys and was studied in the research to be described here. Materials and Methods The specimens used in this investigation were prepared by nitriding "pure" iron. This iron was supplied by the Westinghouse Research Laboratories and is the product bearing their trade name "Puron"; it contains about 0.04 wt pct total impurities, the major portion of which is oxygen. Specimens were ribbons several inches long, a tenth of an inch wide, and 0.125 mm thick; this was the

Jan 1, 1951

By Don B. Carson, Donald L. Katz

NATURAL gases under pressure form crystal-line hydrates with water. Experimental data are reported on four-phase equilibrium for the methane-propane-water, methane-pentane-water, and methane-hexane-water systems. Temperatures and pressures for equilibrium between gas, water-rich liquid, hydrocarbonrich liquid, and hydrate were measured, as well as the percentages of methane and propane in the hydrate. The data indicate that natural gas hydrate behaves as a solid solution and that pentanes and heavier hydrocarbons do not enter into the solid phase. Vapor-solid equilibrium constants are presented that permit the approximation of the conditions for hydrate formation, from the composition of a gas. INTRODUCTION Natural gas hydrates have been the object of considerable research in recent years, because of the trouble they have caused in the natural-gas and natural gasoline industries. Natural gas hydrates are white crystalline compounds of water and gas, which, under pressure, exist at temperatures considerably above the freezing point of water. Because of the relatively high temperatures at which the hydrates exist, they become a nuisance in high-pressure gas operations where water is present, since their formation causes partial or complete plugging of valves and pipes. From a practical standpoint, the trouble incident to hydrate formation has been solved by dehydration of the gas before it enters the plant or pipe line, or by other remedial measures. Extensive work on gas hydrates in the latter part of the nineteenth century, by Villard1 and others, gave data on methane hydrate and on ethane hydrate. Schroeder summarized these theoretical studies.2 Hammerschmidt3 introduced the information on gas hydrates to the gas industry and Deaton and Frost4-6 gathered a considerable number of data on the behavior of natural gas hydrates. Recent papers7,8 have extended both the data and the theory of these hydrates. At present, data are available on temperatures and pressures of hydrate formation for pure methane, ethane, propane, n-butane, methane-ethane mixtures, methane-propane mixtures, methane-butane mixtures, and some 15 natural gases, all in the presence of excess water. However, up to the present time no method has been available for predicting the temperature at given pressures or the pressure at given temperatures at which natural gases will form hydrates if saturated with water. This paper pre¬sents data on the methane-propane-water, methane-pentane-water and methane-hexane water systems in four phases, one of which is the hydrate. The application of the phase rule to the methane-propane-water data proves that hydrates behave as solid solutions. The data of this paper and those in the literature were used to develop vapor-solid equilibrium constants,8 which permit prediction of conditions of hydrate formation from the analysis of a natural gas.

Jan 1, 1941

By H. l. Burghoff, C. H. Mathewson

THE study of the creep of metals under conditions of prolonged loading has received the attention of many investigators for several years and almost innumerable papers have been published on the various aspects of the subject. As it appeared that much could still be learned from a study of single crystals, the present work was carried out to study the effects of temperature and conditions of loading upon the properties and deformation in tension of single crystals of alpha brass containing about 70 per cent copper and 30 per cent zinc. In particular, it was hoped to obtain information from tests below and above the recrystallization temperature of the material, so that properties such as elastic limit, yield point or critical stress, and manner of deformation might be compared for tensile tests at an ordinary loading rate and for prolonged. loading. Accordingly, short-time tensile tests and creep tests were made at room temperature, 300º, 500° and 700°F. The two latter temperatures are above the lowest possible recrystallization temperature of polycrystalline 70-30 brass. PREVIOUS WORK Clarke and White1 have made creep tests of some copper-zinc alloys, including 70-30 brass, and copper-zinc-tin alloys at temperatures both below and above the recrystallization temperature of the materials considered. Hanson and Wheeler have studied the flow and fracture of single crystals of aluminum for short-time and prolonged tensile loading over a range of temperature extending from room temperature to 400°F., their experiments being made without consideration of the orientations of the test specimens. Extensive creep and fracture tests on single crystals of lead at room temperature have been made by Betty3 and by Baker, Betty & Moore.4 Results of the last-named investigation were published while the present work was in progress. Millers examined the elastic limit of zinc single crystals at and above room temperature by means of creep tests, while Miller and Milligan6 reported the results of tests designed to show the influence of temperature on elastic limit of single crystals of aluminum, silver and zinc. The behavior, of iron crystals under static tensile loading at room temperature was reported by Gensamer and Mehl7 while the present investigation was in progress. Their specimens exhibited a well-defined yield point, below which no appreciable creep could be detected. The manner of yielding proved interesting, as the shape of the creep-time curve for the iron crystals differed from the common type of creep curves. Elongation did not begin immediately, or at least was initially very slow. The rate of elongation then increased continuously and finally decreased to zero. This S-shaped type of elongation-time

Jan 1, 1941

By D. B. Carson, D. L. Katz

Natural gases under pressure form crystalline hydrates with water. Experimental data are reported on four-phase equilibrium for the methane-propane-water, methanc-pentane-water, and methane-hexane-water systems. Temperatures and pressures for equilibrium between gas, water-rich liquid, hydrocarbon-rich liquid, and hydrate were measured, as well as the percentages of methane and propane in the hydrate. The data indicate that natural gas hydrate behaves as a solid solution and that pentanes and heavier hydrocarbons do not enter into the solid phase. Vapor-solid equilibrium constants are presented that permit the approximation of the conditions for hydrate formation, from the composition of a gas. Introduction Natural gas hydrates have been the object of considerable research in recent years, because of the trouble they have caused in the natural-gas and natural-gasoline industries. Natural gas hydrates are white crystalline compounds of water and gas, which, under pressure, exist at temperatures considerably above the freezing point of water. Because of the relatively high temperatures at which the hydrates exist, they become a nuisance in high-pressure gas operations where water is present, since their formation causes partial or complete plugging of valves and pipes. From a practical standpoint, the trouble incident to hydrate formation has been solved by dehydration of the gas before it enters the plant or pipe line, or by other remedial measures. Extensive work on gas hydrates in the latter part of the nineteenth century, by Villardl and others, gave data on methane hydrate and on ethane hydrate. Schroeder summarized these theoretical studies2 Hammerschmidt3 introduced the information on gas hydrates to the gas industry and Dcaton and Frost4-6 gathered a considerable number of data on the behavior of natural gas hydrates. Recent papers7,8 have extended both the data and the theory of these hydrates. At present, data are available on tem-peraturcs and pressures of hydrate forma. tion for pure methane, ethane, propane, n-butane, methane-ethane mixtures, meth-ane-propane mixtures, methane-butane mixtures, and some Is natural gases, all- in the Presence of excess water. However, up to the Present time no method has been available for predicting the temperature at given pressures or the pressure at given at at which natural gases will form hydrates if hydrates with water. 'This Paper Presents data on the methane-propane-water, methane-pentane-water and methane-hex-""e water systems in four phases, one of which is the hydrate. he application of the phase rule to the methane-~ro~ane-water data Proves that hydrates behave as solid solutions. The data of this paper and those in the literature were used to develop vapor-solid. equilibrium constants,8 which permit prediction of conditions of hydrate formation from the analysis of a natural gas.

Jan 1, 1942

By D. B. Carson, D. L. Katz

Natural gases under pressure form crystalline hydrates with water. Experimental data are reported on four-phase equilibrium for the methane-propane-water, methanc-pentane-water, and methane-hexane-water systems. Temperatures and pressures for equilibrium between gas, water-rich liquid, hydrocarbon-rich liquid, and hydrate were measured, as well as the percentages of methane and propane in the hydrate. The data indicate that natural gas hydrate behaves as a solid solution and that pentanes and heavier hydrocarbons do not enter into the solid phase. Vapor-solid equilibrium constants are presented that permit the approximation of the conditions for hydrate formation, from the composition of a gas. Introduction Natural gas hydrates have been the object of considerable research in recent years, because of the trouble they have caused in the natural-gas and natural-gasoline industries. Natural gas hydrates are white crystalline compounds of water and gas, which, under pressure, exist at temperatures considerably above the freezing point of water. Because of the relatively high temperatures at which the hydrates exist, they become a nuisance in high-pressure gas operations where water is present, since their formation causes partial or complete plugging of valves and pipes. From a practical standpoint, the trouble incident to hydrate formation has been solved by dehydration of the gas before it enters the plant or pipe line, or by other remedial measures. Extensive work on gas hydrates in the latter part of the nineteenth century, by Villardl and others, gave data on methane hydrate and on ethane hydrate. Schroeder summarized these theoretical studies2 Hammerschmidt3 introduced the information on gas hydrates to the gas industry and Dcaton and Frost4-6 gathered a considerable number of data on the behavior of natural gas hydrates. Recent papers7,8 have extended both the data and the theory of these hydrates. At present, data are available on tem-peraturcs and pressures of hydrate forma. tion for pure methane, ethane, propane, n-butane, methane-ethane mixtures, meth-ane-propane mixtures, methane-butane mixtures, and some Is natural gases, all- in the Presence of excess water. However, up to the Present time no method has been available for predicting the temperature at given pressures or the pressure at given at at which natural gases will form hydrates if hydrates with water. 'This Paper Presents data on the methane-propane-water, methane-pentane-water and methane-hex-""e water systems in four phases, one of which is the hydrate. he application of the phase rule to the methane-~ro~ane-water data Proves that hydrates behave as solid solutions. The data of this paper and those in the literature were used to develop vapor-solid. equilibrium constants,8 which permit prediction of conditions of hydrate formation from the analysis of a natural gas.

Jan 1, 1942

By Bernard Kopelman

The particle size of tungsten metal powder used to make tungsten wire for use in radio tubes and incandescent lamps must be closely controlled if the highly desirable feature of nonsagging is to be achieved. Our knowledge of factors affecting the particle size of tungsten powder has been limited by lack of any extensive literature on the subject. There are no publications in the English language discussing this problem in any but the most general terms. In this paper the published experimental information on this subject is reviewed. Based on the published data and some experimental data obtained by the author, a general theory of factors affecting the particle size of tungsten metal powder obtained by reduction of the oxides in hydrogen is offered. The various forms of the tungsten oxides and tungsten metal used in the experiments described were those prepared by commercial processes, so that the experimental results obtained on a laboratory scale would be more directly applicable to actual commercial reduction conditions. The effects of time of reduction, temperature. and concentration of water vapor in the hydrogen were observed by counting microscopically the particle distribution obtained. Such a method is very time-consuming, but the data obtained by this method are more reliable and more fundamental than those obtained by any of the several instruments available for measurement of particle size. Review of the Literature Until the year 1912, tungsten powder was prepared commercially by reducing tungstic oxide in the presence of carbon or one of its compounds (such as glycerin or ethylene glycol), usually by firing the mixture in a closed fire-clay crucible. The resultant powder contained about 95 per cent tungsten.' When reduction of tungsten oxides by H² was introduced Commercially,²,³ several investigators became concerned with the equilibria between tungsten metal and its several oxides in an atmosphere of hydrogen and water vapor.4-l3 While these many investigations were in fair agreement on the equilibria WO³ + H2 = WO2 + H2O and WO2 + 2H2 = W + 2H2O there arose considerable controversy as to the chemical composition of the oxide between WO³ and WO², because of very poor agreement on the equilibrium constant of this intermediate oxide reduction reaction. The controversy on this intermediate oxide has been in progress for more than 100 years. Thus Malguti,14 in 1835, decided it was WO2.56 In 1857, Riche15 proposed the formula W³O8. Usler,16 in 1865, confirmed the existence of WsO8 and further proposed W1O1l. In 1897, Desil7 agreed upon W²O8 but also found W5O14.

Jan 1, 1947

By Bernard Kopelman

The particle size of tungsten metal powder used to make tungsten wire for use in radio tubes and incandescent lamps must be closely controlled if the highly desirable feature of nonsagging is to be achieved. Our knowledge of factors affecting the particle size of tungsten powder has been limited by lack of any extensive literature on the subject. There are no publications in the English language discussing this problem in any but the most general terms. In this paper the published experimental information on this subject is reviewed. Based on the published data and some experimental data obtained by the author, a general theory of factors affecting the particle size of tungsten metal powder obtained by reduction of the oxides in hydrogen is offered. The various forms of the tungsten oxides and tungsten metal used in the experiments described were those prepared by commercial processes, so that the experimental results obtained on a laboratory scale would be more directly applicable to actual commercial reduction conditions. The effects of time of reduction, temperature. and concentration of water vapor in the hydrogen were observed by counting microscopically the particle distribution obtained. Such a method is very time-consuming, but the data obtained by this method are more reliable and more fundamental than those obtained by any of the several instruments available for measurement of particle size. Review of the Literature Until the year 1912, tungsten powder was prepared commercially by reducing tungstic oxide in the presence of carbon or one of its compounds (such as glycerin or ethylene glycol), usually by firing the mixture in a closed fire-clay crucible. The resultant powder contained about 95 per cent tungsten.' When reduction of tungsten oxides by H² was introduced Commercially,²,³ several investigators became concerned with the equilibria between tungsten metal and its several oxides in an atmosphere of hydrogen and water vapor.4-l3 While these many investigations were in fair agreement on the equilibria WO³ + H2 = WO2 + H2O and WO2 + 2H2 = W + 2H2O there arose considerable controversy as to the chemical composition of the oxide between WO³ and WO², because of very poor agreement on the equilibrium constant of this intermediate oxide reduction reaction. The controversy on this intermediate oxide has been in progress for more than 100 years. Thus Malguti,14 in 1835, decided it was WO2.56 In 1857, Riche15 proposed the formula W³O8. Usler,16 in 1865, confirmed the existence of WsO8 and further proposed W1O1l. In 1897, Desil7 agreed upon W²O8 but also found W5O14.

Jan 1, 1947

By J. H. Lightfoot, Stuart E. Buckley

DEEP drilling has led to the development of numerous pools which yield products consisting predominantly of natural gas accompanied by high-gravity water-white or slightly straw-colored liquid. Yields of this "condensate" or "distillate," as it is commonly called, vary from traces to over a hundred barrels per million cubic feet of gas. The fact that this liquid exists in the reservoir as an integral part of the gas phase and is formed by condensation attending simultaneous reduction of pressure and temperature after its entry into the well was apparently first recognized about 1932.1 The nature of the physical phenomena involved in this condensation was clarified for the petroleum industry in 1933 by a report by Sage, Schaafsma, and Lacey2 of the results of an experimental investigation of the behavior of mixtures of methane and propane. Search of the literature has revealed that the condensation of liquid from gaseous mixtures by isothermal pressure reduction is not a new discovery. Kuenen was led by theoretical considerations to expect such a phenomenon, and in 1892 reported3 the results of experimental verification of his deductions. This was followed by a considerable amount of work on the phase relations of mixtures by Kuenen4,5,6 and by others,7,8 mostly in European universities. Since 1930 investigators in this country have reported experimental data on the properties and behavior of a number of hydrocarbon systems.9-17 It is now generally known that in the presence of natural gas the solubility in the gas phase of the heavier and normally liquid hydrocarbons increases rapidly with increasing pressure above 500 to 1000 lb. per sq. in. Thus, at pressures of 2500 lb. per sq. in. or higher a gas may contain appreciable quantities of hydrocarbons with normal boiling points as high as 600°F., which in turn may be condensed from the gas phase by the reduction of their solubility therein attending pressure reduction. The combined effects of pressure and temperature on condensation and vaporization of mixtures are most readily visualized by the study of phase diagrams. Since the construction, application, and interpretation of such diagrams have been described fully in readily available literature, 18-20 this paper will not review the theoretical aspects of this subject. While the behavior of gas-distillate systems is now clearly understood, at least in a qualitative way, most of the published work deals with the results of laboratory studies of binary systems or of synthetic mixtures of hydrocarbons, and although several systematic investigations of the effects of separator pressure and temperature on the yields of liquid product from gas-distillate wells have been made21.22 it appears that in all cases the limitations have precluded the construction of even approximately complete phase diagrams for naturally occurring systems. There has

Jan 1, 1941

Duval Corporation, the copper -producing subsidiary of Pennzoil United, Incorporated, operates two plants south of Tucson, Arizona: Esperanza and Sierrita. The newest, the Sierrita mine and mill, came into full production in 1971 at a rate of 72,000 tpd (now 87,000 tpd) which at that time made it the largest designed copper plant in the world. In 1968, the largest milling units then available were selected; these included fourteen 16$ ft by 19 ft long ball mills (5 m by 5. 9 m), each equipped with a 3,000 hp motor. The primary crushing plant contains two 60 in. by 89 in. Allis- Chalmers gyratories; each is constructed for two-side dumping by 120- and 150-ton trucks. Access to the maintenance areas to service the drive motors, eccentrics, apron feeders, and speedup conveyor is through hatches between the crushers. This area also contains a good- sized elevator and a stairway. The rather shallow dump pocket, the 300 -ton crushed ore pocket, and the overall design make for a fine, compact arrangement for two 60 in. crushers installed in a total height of 89 ft (27. 13 m) from dump level to top-of-concrete at the lowest level beneath the collecting or speedup belt. This efficient layout is reflected in the short changeout time for mantle and concaves (8 and 30 hours respectively) and the low crushing cost of $0.0416 per ton (first half of 1975). The crushers are installed on 64 ft (19.5 m) centers (Bougainville and Palabora, both with 54 in. crushers, are 55 and 43 ft or 16.76 and 13. 1 m respectively). The switchgear room is located between the truck dumping positions on one side of the installation and the hydroset units on the other side, with dust collecting equipment mounted over the latter. Protection of these units from rocks falling from the trucks is provided by concrete walls. Truck dumping is controlled from a central 25 ft high (7.6 m) control room, which permits fine observation of operations. Removal of oversize boulders from the dump pockets is done with a hydraulic grapple or a rock hook or sling attached to the auxiliary crane hook. Spare mantle stands and a maintenance room with a zinc melting furnace are located at one end of the surface facilities. The maintenance room is equipped with an access door for the crane, which is equipped with 80- and 20-ton hoists. The two 84 in. (2. 135 m) apron feeders receiving the 6 in. (152 mm) crushed rock discharge onto a 72 in. (1. 83 m) collecting and wear belt operated at a speed compatible with the 60 in. (1.524 m) takeaway belt running at a speed of 630 fpm (192 mpm). This belt feeds a 54 in.

Jan 1, 1978

By E. J. Dulis, G. V. Smith

AS reported several years ago,' nitrogen may be taken up from the atmosphere by austenitic Cr-Ni steels during creep or creep-rupture tests. This was indicated by chemical analysis and by the appearance of a new microstructural phase, or phases, tentatively identified as chromium nitride (S), at the surface or at the intergranular cracks associated with fracture. The nitrogen pickup was observed to be dependent on time, temperature, and deformation. In a more recent investigation, a sample was obtained in which there was sufficient of the precipitate to suggest that it could be readily identified by X-ray diffraction. This sample had been taken from a 1/4 in. diam creep-rupture specimen of annealed, type 304L stainless steel of the following initial composition: C, 0.03 pct; Mn, 0.65; P, 0.010; S, 0.019; Si, 0.54; Cr, 19.50; Ni, 12.02; N, 0.031; and Al, 0.005. The specimen had ruptured after 10,470 hr at 1500°F (2000 psi). In this case nitrides were distributed across the whole section of the sample, Fig. 1. The precipitate occurred both at the grain boundaries and within the grains; the latter precipitate had in some cases the appearance of pearl-ite, and in others was distinctly Widmanstatten. Chemical analysis of the sample after test showed 0.64 pct "soluble" nitrogen (soluble in 1:1 hydrochloric acid: water) and 0.18 pct "insoluble7' nitrogen (insoluble in the hydrochloric acid solution but dissolved by fuming sulphuric acid). For identification of the precipitate by X-ray diffraction, the matrix in the surface layer of the specimen was dissolved by prolonged attack in an alcoholic solution of picric and hydrochloric acids. The appearance of the specimen surface after such etching is shown in Fig. 1c. The diffraction pattern of the surface-concentrated precipitate was obtained with a recording spectrometer in both the forward and back-reflection regions (the latter by adapting a special fixture to the conventional X-ray unit). The observed X-ray diffraction lines, Table I, show the presence of Cr,N and CrN; the agreement with interplanar spacings calculated from reported data2,3 is quite good. Since it has been suggested' that CrN dissolves only in concentrated sulphuric acid, whereas Cr2N dissolves in dilute hydrochloric or sulphuric acids, an effort was made to distinguish between the two nitrides. This proved possible, inasmuch as etching in a dilute solution of hydrochloric acid gave a sample in which microscopic examination showed that much of the Widmanstatten-pearlitic precipitate within the grains had been eaten out, leaving the grain boundary precipitate in relief, and which, when examined by X-ray diffrac-

Jan 1, 1953

By O. Schaaber

THE existence of isothermal martensite without the presence of the athermal form thus far has been established only in a 6 pct Mn, 0.6 pct C steel' and a 23 pct Ni, 3.5 pct Mn-Fe alloy.' " Theoretical calculations, moreover, predict this phenomenon to be observable only within narrow composition limits.' In all other steels, it is generally considered that martensite inevitably forms upon cooling below the M, temperature. Even the possibility of isothermal martensite transformation has been questioned for the common steels, although Averbach and Cohen" showed that martensite formation does not stop when the cooling is arrested and that as much as 5 pct retained austenite may transform isothermally to martensite at room temperature. This note presents some observations made on a number of low alloy steels by dilatometric and inductive measurement of isothermal austenite transformation at various temperatures close to the Ms. In the dilatometer studies reported previously, austenitized specimens were immersed in a salt bath maintained at proper temperature and immediately inserted into the dilatometera8' already at thermal equilibrium with the bath. The dilation was read on a dial gage divided into 0.001 mm intervals. Induction measurements were made with a separate excitation source and a test coil, sealed together in a salt-tight case. The increase in the induced voltage caused by the transformation products was recorded at a paper speed of 4 mm per sec. The steels studied are listed in Table I. Specimens prepared from steels 1 and 2 were in the form of hollow cylinders 60 mm long, 10 mm ID, 14 to 16 mm OD, while specimens of steels 3 and 4 were in the form of notched-bar impact test specimens, DVM type. Specimens of steel 5 were in the form of strip, 7x0.3 mm. In the bainitic range, curves representing the amount of transformation vs log time have a single step appearance, as is shown by the curve of isothermal transformation at 320°C in Fig. 1.Y ransformation proceeds in accordance with the Austin-Rickett equationo P -----------= k t" 100-P where P is the percentage of transformed austenite, t is time, and k and n are constants. Near the M, temperature, however, complex curves having two steps are observed. As shown in a previous papera for steel 3 isothermally transformed at 245"C, such complex curves can be separated into two separate transformations or reactions each following the Austin-Rickett equation. The values of n in the equation for a number of such two-step transformations are listed in Table 11 for steel 1. At transformation temperatures of 250" and 235"C, evidence of a second transformation is very

Jan 1, 1956