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By John J. Strohl, Henry J. Schwellenbach

This paper relates the results obtained by decreasing the size of feed to a rod mill screen circuit. As would be expected, added production was gained and a finer grind with no tonnage loss was made possible.

Jan 12, 1950

By W. A. Bruce

Studies of reservoir behavior of 12 Smackover limestone oil and condensate pools are presented. Buckner, Midway, McKamie, Magnolia, Mt. Holly, Schuler (Reynolds) and Village are treated in considerable detail and subjected to analysis with an electrical device for analyzing reservoir behavior. Results and comparisons of these analyses are presented. In addition to these reservoir-behavior studies, an attempt is made to assemble trans-missibility and storage data on the Smackover limestone formation from cores and logs taken in dry holes and producers. This together with the behavior of individual reservoirs leads to a better understanding of the formation as a porous aquifer. The ultimate purpose of this type of study is to improve predictions concerning the future behavior of these pools in such a system. Predictions are presented for several pools. Introduction In 1937 the Phillips Petroleum Co. drilled its J. D. Reynolds No. I to the Smackover limestone formation at Snow Hill, Arkansas. This well found oil in the porous, permeable, upper part of the Smackover, thereafter referred to as the Reynolds lime. Since then, six oil pools and six condensate pools have been discovered in the Reynolds lime, and more than 75 dry holes have explored parts of this formation. By the first of 1943, 44 million barrels of oil and 83 billion cubic feet of gas had been withdrawn from the various reservoirs. The original reserves estimated by the Arkansas Oil and Gas Commission were 342 million barrels of oil and rzoo billion cubic feet of gas. So far all of the production has been from anticlinal structures, most of which are asymmetric and have their axes roughly perpendicular to the dip of the formation top. This is indicated in Fig. I, which shows the pools, dry holes drilled, and contours on top of the Smackover.' These pools are of particular interest for reservoir-behavior studies because the production and drilling has been controlled, and in most cases the records of reservoir data are complete. In addition to the excellent production and pressure information available, more than one half of the wells drilled were cored and all of them were electrically logged. All of the pools show evidence of water drive. While this paper is in a sense a collection of reservoir-behavior studies for several different pools, there has been an attempt to go one step further and to show the importance of the iormation as a porous continuum or a single aquifer in which the withdrawals of fluids from any pool has an important effect on the behavior of all of the pools. An effort will be made to show that the water drives of these pools are dependent upon a much larger area of the Smackover limestone than that occupied by the petroleum accumulations.

Jan 1, 1944

By W. A. Bruce

Studies of reservoir behavior of 12 Smackover limestone oil and condensate pools are presented. Buckner, Midway, McKamie, Magnolia, Mt. Holly, Schuler (Reynolds) and Village are treated in considerable detail and subjected to analysis with an electrical device for analyzing reservoir behavior. Results and comparisons of these analyses are presented. In addition to these reservoir-behavior studies, an attempt is made to assemble trans-missibility and storage data on the Smackover limestone formation from cores and logs taken in dry holes and producers. This together with the behavior of individual reservoirs leads to a better understanding of the formation as a porous aquifer. The ultimate purpose of this type of study is to improve predictions concerning the future behavior of these pools in such a system. Predictions are presented for several pools. Introduction In 1937 the Phillips Petroleum Co. drilled its J. D. Reynolds No. I to the Smackover limestone formation at Snow Hill, Arkansas. This well found oil in the porous, permeable, upper part of the Smackover, thereafter referred to as the Reynolds lime. Since then, six oil pools and six condensate pools have been discovered in the Reynolds lime, and more than 75 dry holes have explored parts of this formation. By the first of 1943, 44 million barrels of oil and 83 billion cubic feet of gas had been withdrawn from the various reservoirs. The original reserves estimated by the Arkansas Oil and Gas Commission were 342 million barrels of oil and rzoo billion cubic feet of gas. So far all of the production has been from anticlinal structures, most of which are asymmetric and have their axes roughly perpendicular to the dip of the formation top. This is indicated in Fig. I, which shows the pools, dry holes drilled, and contours on top of the Smackover.' These pools are of particular interest for reservoir-behavior studies because the production and drilling has been controlled, and in most cases the records of reservoir data are complete. In addition to the excellent production and pressure information available, more than one half of the wells drilled were cored and all of them were electrically logged. All of the pools show evidence of water drive. While this paper is in a sense a collection of reservoir-behavior studies for several different pools, there has been an attempt to go one step further and to show the importance of the iormation as a porous continuum or a single aquifer in which the withdrawals of fluids from any pool has an important effect on the behavior of all of the pools. An effort will be made to show that the water drives of these pools are dependent upon a much larger area of the Smackover limestone than that occupied by the petroleum accumulations.

Jan 1, 1944

By Edmund C. Pechin

THE writer approaches this subject with a great deal of diffidence —first, because it is utterly impossible to treat it satisfactorily within the limits of a paper, and, secondly, because the larger development is of so comparatively a recent date as to make authoritative data on some interesting points unavailable. For over one hundred years small charcoal-fnrnaces have been in existence, at widely scattered points, making a few tons of iron daily, and then gradually increasing to a daily output of, say 10 to 12 tons, as the market widened. With the exhaustion of local supplies of wood, inaccessibility to market, and sharp competition, bringing lower prices, many were compelled from time to time to make temporary stops, and finally to cease altogether. During the first half of the century there were at different times in operation between 75 and 90 charcoal furnaces. The last Directory of the Iron and Steel Works of the United States (1890) gives 19 as the number of charcoal-stacks in Virginia. Of these several are cold, and, it is

Jan 1, 1891

By Allen J. Johnson

With a realization of the rapidly increasing importance of automatic stokers as a medium for domestic heating, the Anthracite Institute Laboratory has conducted extensive investigations, over a period of several years, to determine the various outstanding characteristics of stoker design and performance. The purpose of this paper is to summarize these findings as a guide to current practices. Stokees Investigated One or more models of the underfeed stokers listed below were included in the various phases of this investigation: Beckley Gilkoal Burnwell Iron Fireman Combustioneer Motor Stokor Electric Furnace Man Norristown Super-stoker Erie Heat Generator Whitney Fire Ball (Tests Incomplete.) Fuel Saver Principles of Construction.—The operating principle of the leading makes of underfeed stokers is similar (Fig. 1). A plunger1 or slowly revolving worm2, conveys the buckwheat or rice sizes of anthracite to the center of a specially constructed tuyere pot where air is admitted to the coal through suitable ports of varying design. As the fuel burns, it is slowly forced to the outside circumference of the tuyere by the pressure of the incoming coal; eventually the ash falls over the edge of the pot, either entirely by gravity or aided by mechanical sweepers. In at least one model, the entire firepot revolves. While various special details have been included in the design of a number of stokers, they do not affect the general principles as described above, and therefore have not been included in this discussion.

Jan 1, 1936

By Allen J. Johnson

With a realization of the rapidly increasing importance of automatic stokers as a medium for domestic heating, the Anthracite Institute Laboratory has conducted extensive investigations, over a period of several years, to determine the various outstanding characteristics of stoker design and performance. The purpose of this paper is to summarize these findings as a guide to current practices. Stokees Investigated One or more models of the underfeed stokers listed below were included in the various phases of this investigation: Beckley Gilkoal Burnwell Iron Fireman Combustioneer Motor Stokor Electric Furnace Man Norristown Super-stoker Erie Heat Generator Whitney Fire Ball (Tests Incomplete.) Fuel Saver Principles of Construction.—The operating principle of the leading makes of underfeed stokers is similar (Fig. 1). A plunger1 or slowly revolving worm2, conveys the buckwheat or rice sizes of anthracite to the center of a specially constructed tuyere pot where air is admitted to the coal through suitable ports of varying design. As the fuel burns, it is slowly forced to the outside circumference of the tuyere by the pressure of the incoming coal; eventually the ash falls over the edge of the pot, either entirely by gravity or aided by mechanical sweepers. In at least one model, the entire firepot revolves. While various special details have been included in the design of a number of stokers, they do not affect the general principles as described above, and therefore have not been included in this discussion.

Jan 1, 1936

By Oliver Bradley

THE utilization of casing-head gas in the manufacture of casing-head gasoline by both the absorption and the compression method is a most important factor in the conservation of our natural resources.. Any industry connected with the oil business, in general, possesses particular attraction for a large number of people not conversant with its basic principles, for the reason that the large fortunes made in the production and utilization of petroleum and its products have been given undue prominence. The general impression of the public that enormous profits are to be realized in the casing-head gas industry with minimum expenditures of both capital and effort has, in a large measure, accounted for the phenomenal expansion of the industry in recent years and, likewise, has resulted in many mistakes and loss of investment funds. It is true that many installations have been very profitable, but such instances are always the result of careful planning, experienced judgment and conservative estimates. The inception and subsequent activity in the manufacture of casing-head gasoline, enabling the business to assume an important position in the petroleum industry, are of, comparatively recent origin, as its greatest growth, particularly in Oklahoma, occurred during the years 1917 and 1918. Much information must yet be secured and systematized concerning the methods of manufacture of gascline from high-yield casing-head gas, and a large field is still open for the application of accumulated experience and good engineering practice in devising better methods of extracting gasoline from casing-head gas of the poorer grades. The absorption process is coming into general use as a most efficient system of treating casing-head gas, and even so-called dry gas. In fact, there is a decided tendency toward the universal adoption of the absorption process as against compression methods. However, a general discussion of the relative merits of these two systems is not within the scope of this article.

Jan 9, 1920

Executive-A. R. LEDOUX, chairman. Membership-J. V. W. REYNDERS, chairman. Finance-J. V. N. Dorr, chairman. Library-E. GYBBON SPILSBURY, chairman. Papers and Publications-BRADLEY STOUGHTON, chairman. Nominations-POPE YEATMAN, chairman.

Jan 12, 1919

By Lyle L. Marsh, David L. Douglas

CORRELATION was made between the heat treatment and hardness of three U-Ti alloys ranging in composition from 8.5 to 50 atomic pct Ti. The following important observations were made: 1) A direct quench of y U-Ti solid solution resulted in the formation of a hard martensitic phase in low-titanium alloys. 2) Subsequent tempering initially increased the hardness by the precipitation of a fine dispersion of U2Ti; further precipitation of U2Ti with tempering time eventually resulted in softening. 3) High-hardness levels were obtained also by isothermal transformation of an 8.5 atomic pct Ti alloy at 400º and 500°C. 4) The crystal structure of the phases present at the solution-treating temperature (one region in the phase diagram excepted) and the temperature within a given phase region affected the hardness of both quenched and isothermally transformed alloys. Introduction It has been known since 1887 that the mechanical properties of metals were dependent upon their microstructure. Sorby pointed out in that year that annealed gray iron castings were softer than chilled iron castings by virtue of the graphite which had replaced hard cementite in the microstructure. Over the years, interest has increased in the effect of microstructure on the mechanical properties of metals, and now high-strength levels may be achieved by bringing about the dispersion of a second phase or by other microstructural adjustments. The nature of a second phase in an alloy strongly influences the properties. For example, the size, shape, amount, and distribution of a second phase plays a very important role in the ultimate properties of an alloy. Microstructural control is achieved by heat treatments. Hence, any alloy system of potential use should be understood in terms of its response to heat treatment and the resultant effects upon the properties.

Jan 1, 1958

By K. S. Lane

The problem of stability of slopes in reservoirs is one of real interest in civil engineering. The problem is whether the valley walls will remain stable or whether they are likely to slide as conditions are changed by storage of water in the reservoir. If major slides are indicated, as on the walls of relatively steep canyons, one must estimate whether they will be so located and of sufficient size as to interfere with operation of the reservoir-as by blocking the outlets, or by displacing sufficient water to over-top the dam in a huge wave. Some cases involve problems in soil mechanics for slides in earth or weaker rock; other locations need the assistance of rock mechanics for slides in harder rock. While this is not a new problem, attention has recently been focused on its importance by the hugh landslide into the Vaiont reservoir in 1963, which claimed the lives of over 2000 people and forced abandonment of the dam and powerhouse. VAIONT RESERVOIR SLIDE Fig. 1 shows Vaiont Dam in Italy which is a double curvature arch, 875 ft high, located on a tributary of the Piave River, north and west of Venice. When completed in 1960 it was the highest arch dam in the world. In 1960 a sizable landslide (some 700,000 cu yd) occurred on the left abutment a short distance above the dam. Following this, the reservoir was held down for construction of a by-pass tunnel through the right valley wall to insure connection with the upper end of the reservoir in event of further slides. In October 1963 a giant landslide occurred on the left valley wall, over a width of some 14 miles (see Fig. 2). Over 300 million cu yd slid into the reservoir, displacing the water and forming a hige wave 700 ft above the top of the dam as it hit the opposite, or right, wall of the valley. The wave then passed some 500 ft over top of the dam, followed down the tortuous winding canyon and debouched into the

Jan 1, 1967

By Chung Yu Wang, Guy C. Riddle

There are found in nature upward of II2 minerals containing antimony, but only a few of them, listed in Table I, can be considered as antimony ore-forming minerals. Stibnite (Sb2S3), antimony sulphide or glance, is the principal ore of antimony. The oxide ores—cervantite, kermesite, valentinite, sernarmontite—occur sparingly in nature. Dry methods are generally adopted for the extraction of the metal. Electrometal-lurgical methods have had much attention in America and Germany and have not yet found, on economic grounds, practical or extended application, except in a few places. During recent years, treatment of the poor grades of the ore, especially sulphide, by ore-dressing methods, has commanded some attention and been adopted at a few plants. The impure sulphide of antimony, resulting from the liquation process, is called lLneedle," "liquated" or "crude" anti- mony, and the refined metal itself is called antimony "regulus." The different processes for the treatment of antimony ores are shown in the diagram of Fig. I. Liquation of Crude Antimony The first step in the smelting of antimony is a simple one, the process of LLliquation," which produces crude or needle antimony. Ores containing $ 50 per cent Sb are used in the liquation process for the production of crude. The temperature required for liquation is between 550' and 600°C. Ores to be liquated are broken to about walnut size. If the pieces are larger than this, the low heat used will not penetrate' effectively, and if they are smaller the ore tends to pack too closely for adequate penetration. A packed charge also prevents the free escape of the fused sulphide. Intermittent Liquation in Crucibles The unique type of furnace that is in use in China for smelting is not highly efficient but is simple in construction and operation. The furnace is generally built

Jan 1, 1944

By A. M. E. Eilers

No one who has visited our Western mining districts, and studied the economical part of the beneficiation of the ores occurring all over that vast extent of country, can underrate the high importance of the above subject. By far the larger number of the districts which contain smelting ores, i.e., argentiferous and auriferous lead, or copper ores, are situated in the Great Basin, that great plateau between the Rocky Mountains on the east, and the Sierra Nevada on the west, almost the whole of which is comprised at present in the boundaries of Nevada, Utah, and part of Arizona. This region is essentially a barren country. The extreme dryness of the atmosphere permits but a scanty vegetation in the plains ; and even in the detached mountain-chains running through it-generally from N. to S., or from N. W. to S. E.-there are no trees found except dwarfed pines and mahogany, at the head of sheltered ravines, and a few cottonwoods and willows, which fringe the insignificant streams, before the water sinks in the arid plains. Nearly all the mountain-chains in this region are rich in silver ores. That class of these ores which is adapted to amalgamation, and rich in silver, has been worked with profit for more than ten years. But before the advent of the transcontinental railways, mining was restricted to these ores alone, and the consumption of fuel could be met with the scanty supply of forest trees in the immediate vicinity of the mining districts. Since, however, the Union and Central Pacific Railroads have brought the Great Basin nearer to the commercial centres of the East and the Pacific coast, thus reducing the expenses of freight and labor materially, other silver deposits, containing poorer ores in greater abundance, have been rapidly taken

Jan 1, 1873

By Stephen Taber

Introduction.............................. 62 Asbestiform Minerals.......................... 63 Chemical and Mineralogical Relations............... 63 Physical Properties........................ 64 Types of Asbestos............................ 65 Origin of the Fibrous Structure...................... 66 Views of Previous Investigators.................... 66 Discussion of the Evidence.................... 67 Conclusions........................... 69 Origin of Cross-fiber Veins....................... 71 Chrysotile Veins......................... 72 Structural Features of Cross-fiber Veins............... 78 Veins of Crocidolite and Other Fibrous Amphiboles........... 83 Origin of Slip-fiber........................... 84 Origin of Mass-fiber........................... 86 Discussion............................... 87 IntRoduCtion The term asbestos, as commonly used, includes half a dozen minerals all having a well-developed fibrous structure, but differing in chemical composition and in some of their physical properties. In its strict application the name is limited to the fibrous varieties of the monoclinic amphiboles. Commercially, however, the most important of the asbestiform minerals is chrysotile, a fibrous variety of serpentine. About 95 per cent. of the asbestos used in manufacturing is chrysotile, and it commands a much higher price than any of the other fibrous minerals now on the market. Although the production of asbestos has increased rapidly in recent years, comparatively little has been published concerning its origin. The present paper is preliminary in its nature, and therefore does not pretend to exhaust the subject. The ideas herein developed are the result of field investigation, laboratory experiments in the growth of fibrous

Jan 1, 1918

By K. A. Natarajan, I. Iwasaki

With a platinum electrode the Eh-pH response in aqueous systems follows an empirical relation [Eh = E- 0.059 pH](1) where E usually carries a value between 0.8 and 0.9 v. The same potential (E) is observed with a number of other noble metal electrodes in the absence of surface poisoning and of other well-defined redox couples. Many sulfide mineral electrodes also respond in a similar manner in solutions containing their respective ions over wide pH ranges, especially in the alkaline pH region. Such a parallelism between noble metal and sulfide mineral electrodes points to certain implications of their surface conditions, and the flotation and leaching behaviors of sulfide minerals under aerated conditions may be inferred with respect to the foregoing Eh-pH response. Comparison of Sulfide Mineral and Noble Metal Electrodes [Fig. 1] shows the Eh-pH response of pyrite, galena, chalcocite, and pyrrhotite electrodes, reported by Sato, and some experimental points obtained with a platinum electrode in distilled water. [Eq. 1] is seen to be followed by all these electrodes. It is interesting to note that the response of the pyrite electrode as shown is identical to

Jan 1, 1973

By AIME AIME

WHEN the War Production Board issued its order which will end the use of iron and steel in more than 400 familiar civilian articles, the list of those products formed a fascinating and homeric catalogue of the things we use. Articles for which iron and steel may not be used after a 90-day "tapering-off" period are as workaday as office machinery and as frivolous as cocktail shakers. Mostly they are smaller items-the smallest probably are phonograph needles but in the aggregate they will save tremendous quantities of the metal most needed to win the war. In total war there are no trifles. Interesting proof of this lies in the fact that by eliminating manufacture of blackhead squeezers we shall save 110,000 lb. of steel a year. Out of this steel we might have made four 155-mm. field pieces. We might have made a thousand 3-in. trench mortars, 4400 0.30-caliber machine guns, 55 16-in. shells, 110 200-lb. aerial bombs, or three 15-ton tanks with something left over to arm them.

Jan 1, 1942

By Theodor Zuschlag

Electrical prospecting is the art of exploring the structure of the subsoil in regard to conductivity variations and interpreting the results of such exploration as to their geological meaning. Electrical prospecting has been applied during the last few years with outstanding success, not only to prospecting1 for ore but also to structural studies.2 Both applications have proved helpful to the geologist, and the latter application especially promises to become of still greater importance in the future. The mapping of structures is the most important function of the oil geologist. Oil is lighter than water, therefore in water-bearing beds it will migrate upward until the migration is stopped by a bed impermeable to the oil. Geologic structures such as domes, anticlines, faults and terraces, offer good prospects in the search for oil accumulations and can be traced easily by electrical prospecting, provided they are composed of a series of sedimentary layers of which at least one possesses fair electrical conductivity and follows the general trend of the structure. Conditions for Successful Mapping The first condition, fair electrical conductivity, is met in almost any oil-bearing series, because generally the electrical resistance of a sedimentary bed is identical with the resistance of the more or less saline waters, filling partly or entirely the pores of the rocks.3 Briefly, the electrical resistivity of a bed can be expressed for all practical purposes by the product R X P, where R is the specific resistance of the waters in the rock pores and P a factor depending upon the percentage of water by volume in the rock. The specific resistance of any solution can be computed from the chemical analysis, being primarily a function of the

Jan 1, 1932

By D. Bergekoff

IN the routine examination of a wide variety of metal specimens it is sometimes necessary to have special methods of polishing in order to retain and reveal certain details in each specimen. Among such special cases is the retention of graphite in malleable and gray cast irons, the preservation of all types of nonmetallic inclusions in both hard and soft steels, obtaining a scratch-free surface with soft metals, and avoiding the usual relief effects with very hard specimens such as tool metals con-taining various carbide and nitride phases. It is the purpose of this paper to give an account of some of these special polishing methods in use at the Union Carbide and Carbon Research Laboratories. The polishing procedures outlined have been found to give uniform results. It is obvious that only general rules and the most important working details can be given here. Following these rules, the polisher can obtain satisfactory results if he possesses the necessary patience and has a sincere desire to give as nearly perfect a finish as possible to his work.

Jan 1, 1939

By O. F. Thornton, D. L. Marshall

Results of the determination of the inter stitial water content of several core samples from oil reservoirs are presented. Data obtained by the capillary pressure method, which has recently been developed, are compared with water saturations measured in cores cut with oil-base mud and with values calculated from the electrical resistivity of the formation. The agreement between the capillary pressure and other methods, combined with the fact that similar agreement has been obtained by others, indicates that the capillary method properly applied yields results sufficiently accurate for most engineering purposes. In some cases, it may be possible to extend the utility of data obtained with the capillary pressure method by correlation of interstitial water saturation with more easily measured physical properties of the media. Introduction Several methods are in use for determining or for estimating the interstitial water saturation at given points within oil and gas reservoirs. The direct measurement of the water content of cores obtained with nonaqueous fluid in the hole is believed to be an accurate method under most conditions. The water saturation may be calculated by use of the resistivity curves of the electric log,' although this method is not applicable under conditions that exist in some reservoirs. Recently, a method has been developed and described3.' wherein the interstitial water saturation of cores is measured at a capillary pressure such that conditions existing in the reservoir are simulated. The purpose of this paper is to present data obtained by use of this latter method, and to compare the results obtained with determinations made by other means. Method The theory underlying the capillary pressure method applied to petroleum reservoirs has been discussed adequately in the literature by Garrison,2 Leverett,5 and Others.3,6,7 Briefly, and simply, capillary pressure is defined as the difference in pressure between two contacting fluid phases, such as oil and water. For the simplified sand, water and oil system illustrated in Fig I, the pressure difference can be stated as follows:6 where Pc is the capillary pressure in pounds per square inch, ? is the interfacial tension between oil and water in pounds per inch, r1 and r2 are the radii of curvature of the interface between oil and water in inches. Capillary pressure varies in a given reservoir with depth because of the greater density of the water phase as compared with oil or gas. The following equation expresses the difference in pressure between two points: p1- p2 - h?p/144 [2] where p1 — p2 is the capillary pressure difference in pounds per square inch, h is

Jan 1, 1947

By D. L. Marshall, O. F. Thornton

Results of the determination of the inter stitial water content of several core samples from oil reservoirs are presented. Data obtained by the capillary pressure method, which has recently been developed, are compared with water saturations measured in cores cut with oil-base mud and with values calculated from the electrical resistivity of the formation. The agreement between the capillary pressure and other methods, combined with the fact that similar agreement has been obtained by others, indicates that the capillary method properly applied yields results sufficiently accurate for most engineering purposes. In some cases, it may be possible to extend the utility of data obtained with the capillary pressure method by correlation of interstitial water saturation with more easily measured physical properties of the media. Introduction Several methods are in use for determining or for estimating the interstitial water saturation at given points within oil and gas reservoirs. The direct measurement of the water content of cores obtained with nonaqueous fluid in the hole is believed to be an accurate method under most conditions. The water saturation may be calculated by use of the resistivity curves of the electric log,' although this method is not applicable under conditions that exist in some reservoirs. Recently, a method has been developed and described3.' wherein the interstitial water saturation of cores is measured at a capillary pressure such that conditions existing in the reservoir are simulated. The purpose of this paper is to present data obtained by use of this latter method, and to compare the results obtained with determinations made by other means. Method The theory underlying the capillary pressure method applied to petroleum reservoirs has been discussed adequately in the literature by Garrison,2 Leverett,5 and Others.3,6,7 Briefly, and simply, capillary pressure is defined as the difference in pressure between two contacting fluid phases, such as oil and water. For the simplified sand, water and oil system illustrated in Fig I, the pressure difference can be stated as follows:6 where Pc is the capillary pressure in pounds per square inch, ? is the interfacial tension between oil and water in pounds per inch, r1 and r2 are the radii of curvature of the interface between oil and water in inches. Capillary pressure varies in a given reservoir with depth because of the greater density of the water phase as compared with oil or gas. The following equation expresses the difference in pressure between two points: p1- p2 - h?p/144 [2] where p1 — p2 is the capillary pressure difference in pounds per square inch, h is

Jan 1, 1947

By F. R. Hensel

PuRe silver and silver-lead alloys have been studied as to their suitability for bearing~.' A review of the properties of thallium and the silver-thallium constitutional diagram was made by the author to analyze the possibilities of silver-thallium compositions for antifriction materia1s. t The silver-rich end of the diagram as reported in the literatureg-" was found to be sketchy and it was necessary to carry out corisiderable experimental work to arrive at definite conclusions. Some of the results of this work are reported in this paper. Test Materials In the beginning of the work, only fused alloys were investigated. Later, research Table i.—Composition of Fused Silver-thallium Alloys Tested for Antifriction Properties Percentage Alloy No. of Thallium 1533...................... 0.48 1534.................... 1.06 a31 HT................... 2.04 231....................... 2.10 232 HT................... 3.83 Balance 232....................... 4.07 Silver 233 HT................... 5.86 a33....................... 6.38 a34....................... 9.84 a34 HT................... 10.07 was carried out on electroplating methods and diffusion processes. In preparing the fused alloyst care was taken to exhaust the toxic fumes caused by the thaillium content. The compositions of the series of fused alloys are listed in Table I. The silver-thallium alloys were melted in clay-graphite crucibles and cast into preheated steel molds of 3/4-in, diameter. In the cast condition, they showed a cored structure, as indicated by the micrographs of Figs. I to 3. The etching reagent used was a mixture of 2 grams K2Cr207, 8 C.C. H2S04, and IOO C.C. H20. The cored structure is unsatisfactory for the type of corrosion resistance required for bearing applications, and homogenizing experiments were carried out at various temperatures, the results of which are shown in Figs. 4 through 8. The alloys with a lower thallium concentration, which were heated for 2 hr. at 525°C show an almost completely homogenized solid solution type of structure. With higher thallium concentration, the homogenizing temperature was dropped to 475OC. to eliminate the formation of a liquid phase. It is evident that heating for 2 hr. at this temperature did not iesiilt iii complete elimination of the cored structure. As would be expected, cold-working of the cast structure is an expedient in establishing equilibrium conditions. The fine homogeneous grain structure shown in Fig. 7 corresponds to the cold-worked area under the Rockwell ball penetration when the hardness was taken before heat-treatment. A detailed structural study was made on a cast silver-thallium alloy containing 3.67 per cent thallium. Three micrographs (Figs. 9, 10 and 11) show the transition

Jan 1, 1946