Search Documents

By Hsun Hu

NOT much data are available in the literature on textures in cross-rolled metal sheets. Among the body-centered-cubic metals, a few investigators have studied the preferred orientations developed in cross-rolled and in subsequently annealed molybdenum specimens.1-4 Semchyshen and Timmons5 onstructed complete pole figures for the cross-rolled and subsequently annealed arc-cast molybdenum. They used the conventional photographic method. Similar data on cross-rolled iron are still lacking. In view of the fundamental importance of iron as a basic metal for magnetic alloys and many industrial steels, the present investigation was undertaken in an attempt to understand more about its properties. The material selected for the present work was of high purity, and the textures were determined by the Geiger counter spectrometer technique, which permits the construction of quantitative pole figures. Experimental Procedure The material used for this investigation was NRC (National Research Corp.) high-purity, gas-free iron. The total gas content (N2 + O2 + H2) given was less than 0.026 pct, and the carbon content, less than 0.005 pct. Spectrographic analysis of a 2 in. cast ingot showed the percentage of metallic impurities as 0.0004 pct Cu, 0.0002 pct Mg, 0.001 pct Mn, 0.01 pct Ni, and 0.006 pct Si. A 1 in. thick slice was cut off from the 2 in. cast ingot. It was hot-forged at 850 °C to destroy most of the cast structure. Surface scale was removed by milling the forged piece to a size 2 in. long, 1½ in. wide, and ¾ in. thick. After normalizing at 915 °C for 15 min, the piece was alternately cold-rolled 40 pct and annealed at 750°C in hydrogen to a final thickness of 0.165 in., with a resulting uniform grain size of 0.1 mm.

Jan 1, 1958

By Cyril S. Taylor, Junius D. Edwards

Magnesium is the lightest metal used for structural purposes, for which reason perhaps more than usual interest is attached to measurements of its density. Although the density of solid magnesium has been det,ermined frequently, no measurements of the density of the liquid metal are available. Because of unusual experimental difficulties in measuring the density of the liquid, only a limited number of measurements of good precision were secured. The results, especially the value for the crystallization shrinkage, are of great interest in connection with the casting of the metal. A number of samples for these measurements were made available through the courtesy of the American Magnesium Corp. They were in the form of extruded bars 3/8 in- in diameter and several were of exceptional purity, as indicated by careful analyses. Table 1 gives the density values (at 20" C.) for magnesium of varying degrees of purity. The density was measured at room temperature by comparison of the weight in air, and when immersed in distilled water. The necessary buoyancy corrections were applied, so that the density could be expressed in absolute measure—grams per milliliter. The effect of the buoyancy of the immersed suspension and the surface-tension pull of the water upon the suspension were eliminated from the results by a preliminary weighing of the suspension immersed to the working depth. Great care was necessary to prevent the introduction of a significant error by the formation of gas bubbles upon the clean magnesium surfaces; these are sometimes very minute and easily escape observation. They may be detached by raising the specimen from the water and again immersing; this should be done just prior to completing the weighing. Their formation may be almost entirely prevented during a measurement by previously immersing the specimen in a solution of paraffin in petroleum ether. The thin film of paraffin remaining after the evaporation of the solvent prevents wetting of the magnesium surface by the water. In one such determination, the paraffin coating on a 22-gm. Specimen

Jan 1, 1923

By E. H. Griswold

The surveying of oil wells has in recent months become a common practice in the deep fields of the Mid-Continent area. Borehole surveys have been made by mining companies for many years, but the introduction of such methods into the oil fields has been delayed until the past few years, because the value of survey data was not fully appreciated. The acid and gelatin bottle methods of obtaining the angle of deviation and the floating compass method of obtaining the direction of horizontal drift have been in use for more than 20 years. A photographic recording instrument consisting of a plumb bob, magnetic needle and electrically operated camera was devised and used in the Rand mining fields of South Africa prior to 1912.1 Another and improved photographic instrument, depending upon orientation of the drill pipe instead of polar magnetism for direction, has been invented and used. The acid bottle method has also been used in conjunction with oriented drill pipe. The magnetic compass is not reliable for oil-well work because of the unsymmetrical attraction of the needle to the well casing and possible magnetic formations. Many engineers also concur in the opinion that orientation of the drill pipe from instrument to surface will be inaccurate because of the torque exerted between the drill pipe and walls of the hole, causing the lower sections of pipe to twist. When it is considered that 4000 ft. of 6 in. drill pipe has approximately the same slender-ness ratio as 6 ft. of silk thread, such twisting effects can be readily visualized. The gyroscopic compass has been suggested for use in direction finding, but the high cost of such instruments will prohibit their use, except in special cases. Due to the lack of accurate direction-finding instruments, almost all of the survey work in the Mid-Continent fields has been of the acid bottle method alone.

Jan 1, 1929

By Junius D. Edwards, Cyril S. Taylor

Magnesium is the lightest metal used for structural purposes, for which reason perhaps more than usual interest is attached to measurements of its density. Although the density of solid magnesium has been det,ermined frequently, no measurements of the density of the liquid metal are available. Because of unusual experimental difficulties in measuring the density of the liquid, only a limited number of measurements of good precision were secured. The results, especially the value for the crystallization shrinkage, are of great interest in connection with the casting of the metal. A number of samples for these measurements were made available through the courtesy of the American Magnesium Corp. They were in the form of extruded bars 3/8 in- in diameter and several were of exceptional purity, as indicated by careful analyses. Table 1 gives the density values (at 20" C.) for magnesium of varying degrees of purity. The density was measured at room temperature by comparison of the weight in air, and when immersed in distilled water. The necessary buoyancy corrections were applied, so that the density could be expressed in absolute measure—grams per milliliter. The effect of the buoyancy of the immersed suspension and the surface-tension pull of the water upon the suspension were eliminated from the results by a preliminary weighing of the suspension immersed to the working depth. Great care was necessary to prevent the introduction of a significant error by the formation of gas bubbles upon the clean magnesium surfaces; these are sometimes very minute and easily escape observation. They may be detached by raising the specimen from the water and again immersing; this should be done just prior to completing the weighing. Their formation may be almost entirely prevented during a measurement by previously immersing the specimen in a solution of paraffin in petroleum ether. The thin film of paraffin remaining after the evaporation of the solvent prevents wetting of the magnesium surface by the water. In one such determination, the paraffin coating on a 22-gm. Specimen

Jan 1, 1923

By I. Fatt

The chromalographic effect refers to the separation of constituents in a moving fluid phase which occurs when the phase is passed over a stationary phase, either solid or liquid, or large areal extent. In performing chemical analyses, the large surface contact areal is provided in the case of gas-solid chromatography by-passing the gas over a porous solid and for gas-liquid chronla tog rap hy by-passing the gas over a porous solid which has been coated with a nonvolatile liquid. The porous medium is usually placed in a cylindrical tube, although it may be a relatively flat sheet as in paper chroma-tography. According to one theory,' the separation results from the difference in time spent by various components in the stationary phahe. A gaseous component which is conlpletely insoluble in the stationary phase, or is not adsorbed on the solid, proceeds unimpeded through the column. The versatility and power of the various types of chromatogruphy for the analysis of complex mixtures are evident from their widespread use in performing chemical analyses and from the large number of symposia, books, and papers devoted to the subject in recent years. Associated developments are the application of chromatography to the determination of heats of solution, heats of adsorption, solubilities orK-values, etc. Gas-liquicl chromatography analyses may be characterized by the manner in which the samples are introduced and displaced from the column'. The three techniques used are known as (1) frontal analysis, (3) displacement analysis, and (3) elution analysis. The frontal analysis is performed by displacing an inert gas from the column by a continuous stream of the sample. As indicated in Fig. l(A), all but the first fraction leaving the column represent mixtures rather than pure components. The displacement analysis is conducted by filling the column with a sample, then displacing it with a more strongly adsorbed or absorbed vapor. The resulting chro-matogram is illustrated by Fig. 1(B). Finally, in the elution analysis a small sample of the mixture to be analyzed is introduced as a "plug" into a Rowing stream of carrier gas to give an elution-type chromato-gram. Fig. l(C). The three techniques may be used to provide models to which Row patterns in other physical situations may be compared. PURPOSE OF THE INVESTIGATION The purpose of this investigation was to determine whether natural reservoir rocks, when coated with crude oil, provided sufficient surface areas to give rise to a chromato-graphic separation of light hydrocarbon constituents. The tests were conducted with the light hydrocar-bons in the gaseous state. SANDS TESTED Two sands of widely different permeabilities have been studied: (1) Ventura core (16 md), and (2) Torpedo sandstone core (578 md).Table 1 gives a description of the cores that were tested. With the exception of one frontal-type flow arrangement which was performed on Core 3, the tests were of theelution-type in which a methane-propane mixture was eluted through the core by means of helium. The Ventura core, when impregnated with a weathered crude from the same field, became so impermeable to gas flow that it was necessary to conduct the tests on the granulated cores (Cores 2 and 3).

By R. E. Anderson, R. S. Busk

The mechanical properties of many nonferrous alloys can be modified by heat-treatment. This is almost always effected by controlling the amount of alloy in solid solution and the amount and distribution of second-phase material. The latter often is accomplished through precipitation or age-hardening treatments. The procedure is to solution-heat-treat the metal to provide a supersaturated solid solution and then cause precipitation of the dissolved material at some temperature below the solvus for the alloy. The generally used magnesium sand-casting alloys arc based on the ternary alloy system Mg-Al-Zn. Solid diffusion reactions in the system are slow enough so that a substantially completely supersaturated solulion is maintained even though the metal is relatively slowly cooled from heat-treating temperatures. Consequently, it is general practice to air-cool magnesium-alloy castings from the heat-treatment temperature prior to aging at an elevated temperature. Since it is necessary with many other alloys to cool quite rapidly before aging if optimum benefit from the aging is to be obtained, this study was undertaken to determine the effects of quenching on magnesium alloys. The] alloys used are shown in Table I, being selected as typical of the presently used magnesium alloys. Cooling Rates Since quenching is a means of rapidly extracting heat, there are two factors of interest in its study: (I) the rates of cooling that can be obtained and (2) the effect of various rates on the as-cooled as well as subsequently aged metal. The cooling rates were measured by drilling a hole 1/16- in diameter longitudi~lally in the center of a cylinder % in. in diameter and 3 in. long. The drilling was stopped to place the end of the hole at the center of the long axis of the cylinder. An iron-constantan thermocouple was inserted in this hole and wedged in place. The temperature drop during rapid quenching was recorded by a special1y built General Electric potentiometer recorder capab1e of measuring ' 500°F. temperature drop in 1/10 sec. For the slower cooling rates in air or oil, the temperature drop was measured by a Leeds and Northrup potentiometer recorder with the chart speed increased to One inch per minute' The cylinder was heated to the desired temperature, quenched as desired, and the temperature-time curve recorded. The cooling rates in still air, in oil at 350°F., in water at 180°F. and in a cold, high-pressure water spray were determined in this manner. The results of this study are presented in Fig. I. There is a great difference between water quenching and either air or oil quenching. There is little difference between the hot water quench and the cold water spray. Cooling rates were also

Jan 1, 1945

By E. H. Kelton

THE purposes of this paper are to describe the use of adjustable cut and draw tools as a control test of drawing properties and to point out that no other well-known test or combination of tests determines this quality in zinc and zinc alloys. Rolled zinc has been used for making drawn articles, particularly battery cans, for many years. The development of rolling treatments satisfactory for, these purposes followed the usual course of trial and error experimentation depending upon cooperation with customers to determine what type of material was suitable. A quick test of drawing quality was highly desirable, of course. Scleroscope hardness and temper,1 having no apparent relation to drawing quality, were used simply to check the duplication of rolling treatment and grade of metal. The dynamic ductility1 test, on the other hand, was believed to be so like the drawing operation as to provide a reliable index and came to be taken as the criterion of good drawing properties. Faith in this test was strengthened by the fact that metal having the highest ductility was more satisfactory for operations, such as the manufacture of battery cups, that required several redraws. No distinction was made at that time in specifying metal as to whether it was to be subjected to simple cut and draw, redrawing or forming operations. It developed, however, that in some grades of metal the highest ductility did not coincide with the most satisfactory quality when the material was used for a single draw.

Jan 1, 1934

By H. Shaw

IT is now generally recognized that the gravitational method of geophysical surveying is a valuable aid in elucidating the geological structure of the subsoil and enables the practical geologist to deduce the presence of useful deposits. The particular suitability of the torsion balance to the location of large and important subterranean structures has given rise to a wide. application of this method by many of the important oil companies in their search for future supplies, and so intense have been these efforts that little has been heard of the method in other connections, with the exception of occasional references to its application in the location of hidden deposits of metallic ores, salt and lignite, and a number of accounts of its use in the elucidation of geological structures. Its success in the location of salt domes is well known, and. establishes it as one of the most important of the geophysical methods, especially for the indirect location of oil. In the British Isles, however, no large occurrence of oil is likely to be revealed, and here the practical application of the gravitational method has been restricted almost entirely to the search for ores. This type of survey possesses well marked characteristics, and presents a gravitational problem that has necessitated the development of a special and probably unusual plan of campaign, full details of which it is hoped will shortly be published. The problems and difficulties encountered in this work are of necessity fundamentally related to those met with in the search for oil by means of the torsion balance, but they also possess several special and distinctive features which undoubtedly differentiate them from the obstacles confronting the oil prospector, and which call for special consideration and treatment.

Jan 1, 1928

By John M. McAnerney

In 1955, the U.S. Army started to experiment in Greenland with tunneling in glacial ice and later in frozen glacial moraine. By 1960, long adits and experimental rooms had been successfully excavated. Full mechanization with coal-cutting machinery was most efficient in ice but drilling and blasting were necessary in bouldery moraine. In 1963, the U.S. Army Cold Regions Research and Engineering Laboratory, (USA CRREL; redesignated U.S. Army Terrestrial Sciences Center July 1, 1968) started a tunnel in the frozen silt of central Alaska near Fairbanks. The original adit of 360 ft (109 m) was successfully driven in the permafrost by a twin-rotor tunnel-boring machine, the Alkirk Cycle Miner. The workings were enlarged in 1966 and 1967 by standard mining techniques in which jackhammers, steam points, and augers were compared. A mechanical coal cutter was tried to supplement drilling and blasting. In 1968, airblasting techniques were used successfully for breaking out the frozen silt. All mine products were loaded mechanically and hauled by self-dumping shuttle car. Pneumatic methods of transport were tried for both dust removal and for conveying blast products up to 3-in. maximum size. Studies of the effects of natural winter ventilation through a shaft showed that tunnel closure could be reduced by lowering the adjacent ground temperature. It is concluded that underground openings in frozen ground should be cut and maintained at well below freezing temperatures to hold deformation to a minimum. HISTORICAL BACKGROUND This chapter deals with aspects of tunneling not previously discussed in the conference papers in this book. The chief differences are that the three tunnels lie entirely within frozen material and are relatively small, since they were constructed mainly for research. The primary objectives of the research were to develop underground shelters for military per-

Jan 1, 1970

By H. Shaw

IT is now generally recognized that the gravitational method of geophysical surveying is a valuable aid in elucidating the geological structure of the subsoil and enables the practical geologist to deduce the presence of useful deposits. The particular suitability of the torsion balance to the location of large and important subterranean structures has given rise to a wide application of this method by many of the important oil companies in their search for future supplies, and so intense have been these efforts that little has been heard of the method in other connections, with the exception of occasional references to its application in the location of hidden deposits of metallic ores, salt and lignite, and a number of accounts of its use in the elucidation of geological structures. Its success in the location of salt domes is well known, and establishes it as one of the most important of the geophysical methods, especially for the indirect location of oil. In the British Isles, however, no large occurrence of oil is likely to be revealed, and here the practical application of the gravitational method has been restricted almost entirely to the search for ores. This type of survey possesses well marked characteristics, and presents a gravitational problem that has necessitated the development of a special and probably unusual plan of campaign, full details of which it is hoped will shortly be published. The problems and difficulties encountered in this work are of necessity fundamentally related to those met with in the search for oil by means of the torsion balance, but they also possess several special and distinctive features which undoubtedly differentiate them from the obstacles confronting the oil prospector, and which call for special consideration and treatment.

Jan 1, 1928

By T. E. Leontis, R. S. Busk

WORK was initiated several years ago at The Dow Chemical Company to determine the applicability of powder metallurgy processes to magnesium and its alloys. Although it was found possible to apply the normal techniques of compacting and sintering, it was discovered early that the technique of extrusion offered special promise. This technique and the alloys produced were therefore studied extensively, and the present paper is a partial report of those studies. It is expected that a second paper will discuss more extensively some of the alloy systems simply mentioned here. Although the literature on powder metallurgy is very extensive, there are only two articles dealing with magnesium13,14 and there is no reference to the direct extrusion of the powder of any metal without the preliminary step of compacting. Furthermore, no mention has been made of the possibility of designing alloys by the technique of powder extrusion, particularly alloys that cannot be made in any other way. Sauerwaldl3 discusses the extrusion of magnesium and aluminum powder to produce alloys containing nonequilibrium phases, but again he emphasizes the importance of pre-compacting before extrusion. There seems to be general agreement that some form of hot-pressing is essential to obtain in a compact the full theoretical density of the metal used.'-" The nearest approach to the technique of direct powder extrusion is that of extrusion of pre-sintered compacts,'-" for which the best review through 1944 is that by Kieffer and Hotop.11 Ensign* discussed a specialized technique of "extruding" already compacted and sintered gears for the purpose of sizing. Sauerwa1d13 discussed the compacting and extrusion of magnesium and magnesium-aluminum alloy band-saw chips. The properties of the extruded compacts were found to be comparable with those of extrusions prepared from solid billets. He also extruded a compacted mixture of magnesium and aluminum powder and found the properties to be somewhat different from those obtained on an extrusion made from a cast billet of the same composition. The second reference dealing specifically with the powder metallurgy of magnesium is Stern's patent," in which is described the extrusion of scrap chips and turnings following a hot-pressing and sintering step. Considerable emphasis in most of these articles is placed on the necessity of atmospheric protection to minimize the danger of oxidation. Experimental Procedure The first experiments were made with the small extrusion press shown in fig. 1. With this press, billets of about 1/2 in. diam are used to produce wire

Jan 1, 1951

By Kendall E. Born

Production of crude oil in Tennessee during 1936 approximated 20,000 bbl., about the same as in 1935. Accurate figures are available only for the Glenmary field in southwestern Scott County and the Boone Camp, Seabolt, and Coon Hollow pools in north central Morgan County. Small amounts of oil were produced in the Poplar Cove region of eastern Fentress County, in Tinsleys Bottom along the line between Clay and Jackson Counties, and in the Lock Branch pool of northern Jackson County. The renewed interest in these three pools, which were abandoned for several years, reflects the effect of rising prices for crude oil in Tennessee. Developments in these fields were begun late in 1936 and therefore have had little cffect on the production for the year. A nurnber of small scattered wells in abandoned fields in Clay County were pumped intermittently during the year, but no production figures are available on this production. The acidizing of a number of wells in Scott and Morgan counties reported last1 year has been responsible for an increase of nearly 4000 bbl. over 1935 in this region. Results have shown, however, that the Glenmary pay (Glenmary and Coon Hollow pools) at about the top of the St. Louis limestone, responds more favorably to acid treatment than does the Boone Camp (Boone Camp and Seabolt pools) horizon in the Fort Payne formation of lower Mississippian age. This difference is probably due to the siliceous and argillaceous content of the Boone Camp pay. The only natural gas marketed off the lease in Tennessee during 1936 was in Morgan County, where approximately 10,000,000 cu. ft. were furnished the towns of Sunbright and Burrville and the immediate vicinity. The gas occurs with the oil in the Boone Camp field and small amounts were put on the line from the near-by Coon Hollow and Seabolt pools. There are 11 gas wells in the area. Development Although the presence of petroleum in Tennessee was noted more than one hundred years ago, this state has never been an important

Jan 1, 1937

By R. S. Barneyback

Not much more is known about concrete today than was known to the Romans. For all the research only better tools have resulted to measure the quality of the materials that go into it." In this paper "some of the materials for lightweight concrete and their characteristics are considered and effort is made to indicate their effect on the end result — a structure of lightweight concrete." Lightweight concrete had noble beginnings. It is believed that the first specification for lightweight concrete was written by the Roman Emperor Hadrian in the early years of his reign, 117-138 AD. Hadrian, was an engineer by trade and an Emperor by adoption. He took considerable interest in the structures sponsored during his reign, even to the point of working out the structural details and preparing working drawings for some of the more prominent works in the vicinity of Rome. In order to reduce the dead weight of the 140 ft diam dome of the Pantheon he specified that the lightweight structural concrete members supporting this concrete and tile composite dome were to be fabricated from a concrete containing pumice and scoria. Still standing after 18 centuries of abuse, this structure has been described as the master effort of a great structural genius, the ultimate achievement of Roman engineering skill.' The Romans were the first to employ many concrete techniques we think of as modem innovations. Some unnamed superintendent noted that when a carefully measured amount of pigs blood was measured into each batch of concrete during mixing, the concrete was more durable and exhibited much better resistance to freezing and thawing climates. He no doubt, attributed this success to the appeasement of one of the gods who in return provided protection for the building containing this sacrificial offering in its walls. It is known today that the blood-entrained air in the concrete tends to make mixtures more workable, resistant to moisture penetration and more resistant to frost damage.

Jan 1, 1964

By J. R. Hoffert

ON Oct. 27, 1941, the Sanitary Water Board of the Commonwealth of Pennsylvania called a meeting of the representatives of the coal operators in the Schuylkill River Basin, and frankly suggested to the operators that they "clean up their house" before someone else came in and did it for them; that they should not emulate the railroads with their "public be damned" policy and its fateful results. It had been four years since the passage of the antipollution law of 1937, a law which exempted silt from collieries until such time as a practical method existed for the removal of their water polluting properties. It had been fifteen long years since Sisler, Frazer and Ashmead concluded that 900 million tons of culm and silt had been deposited in Pennsylvania's streams in the process of preparing five and a half billion tons of anthracite for the world's consumers. Fine coal was being "mined" in the streams by "washeries" and river dredges downstream from the collieries, and silt banks no longer held back the endless black stream entering the Schuylkill at the rate of 350,000 tons per month. The coal operators were apparently working on the outmoded assumption that each ton of fine coal prepared displaced a ton of larger sized, more profitable coal. The meeting between the Sanitary Water Board and the coal operators signaled the beginning of the end of Pennsylvania's pollution problems. As a result a committee was formed at that meeting by the operators to find out what conditions were at each colliery. The Bureau assisted in the indication of methods of measurement and sampling and in the development of forms for reporting the needed data. One large producer had its chief engineer supervise the gathering of the information concerning the quantity of waste waters, the amount and sieve analyses of the waste solids, and the existing means for retaining

Jan 3, 1950

By J. L. Jones

1. Brinell tests at progressively increasing temperatures are given for a representative lead-base and a representative tin-base babbitt, showing that the former has superior resistance to deformation at the working temperatures of bearings. 2. Small squares of bearing bronze, tinned and then babbitted with a representative lead-base babbitt and a representative tin-base babbitt were subjected to compressive loading. The lead-base babbitt showed less average compression than the tin-base babbitt. Compression did not materially increase the Brinell hardness of the babbitts. 3. A process and a tool are described for giving smoother and more accurate surfaces to bearings than has heretofore been possible. The following experiments have recently been carried out in the chemical laboratory of the Westinghouse Electric and Manufacturing Co., Pittsburgh, Pa. While the work is incomplete, it is described at the present time because data on the comparative merits of lead-base and tin-base babbitts are of interest in connection with the present shortage of tin. BRinell Habdness of Babbitt at Increasing Temperatures Bearings fail because of wiping, or deformation. Hence tenacity is desirable in a bearing metal, especially tenacity at high temperatures. The Brinell test is commonly regarded as a measure of tenacity. In fact, it has recently been proposed to substitute for Brinell hardness number the expression " tenacity number."l It seemed, therefore, that the Brinell test was especially adapted for the tests described. Disks, 4 in. (101 mm.) in diameter and 1.5 in. (38 mm.) thick, were made of the babbitts to be studied, designated A, B, C. They were poured into metal molds, pyrometer leads being soldered in the center of each disk. The composition of the babbitts was as follows:

Jan 1, 1919

By E. J. Bruderlin

A metallurgical process to be economically successful must be carried on under proper conditions of control and equipment. The question of equipment is always of primary importance. In the distillation process for the recovery of zinc by retorting, the retort is the all-important piece of equipment. Each retort in a working blóck must function as a separate unit. Over-all block efficiency is the result of the ability of the individual retort to withstand the severe conditions of operation for a maximum period of time. Therefore retort manufacture has been an ever present problem with the operator of a zinc-retorting plant. During recent years the zinc-plant operator has been faced with rapid changes in the character of the ores and concentrates. Operating costs have increased as a result of the introduction of the flotation process and the amount of flotation concentrates to be handled. To counteract increasing costs, the operator has found it necessary continually to attempt heavier loading of retorts, until a 45 to 50-lb. charge per cubic foot of retort space has become common practice. Heavy loading has brought about severe firing conditions, which, in turn, have emphasized the necessity for further improving the quality of the retort. Increasing percentages of detrimental impurities in the retort charges have also added to the operator's difficulties. Amarillo Silicon Carbide Retorts At the Amarillo plant of the American Smelting and Refining Co. a retort made of a suitable plastic clay grogged with silicon carbide has been found to best meet the present-day requirements. Retorts of this kind have been in use at Amarillo for 8 years and have shown an average furnace life of approximately 175 calendar days. The Amarillo retort is cylindrical in shape and after burning is approximately 83/4 in, inside diameter by 60 in. over-all length. The wall thickness is 136 in., except for the butt of the retort, which is approximately 2½ in. thick. The retort mud has a shrinkage of 3 per cent, or approximately % in. per foot. The silicon carbide retort after being properly dried weighs about 211 lb. When the retort is fired and ready to go into use the weight decreases to approximately 203 lb.

Jan 1, 1937

By R. W. Smashey, B. J. Piearcey

The structure, composition, and morphology of the carbide phases present in the nickel-base superalloy, Mar-M200, hare been determined and three carbide phases observed. The MC carbide is a solidification product, and the M23 Co and M6C carbides are both prod~icts of solid-state precipitation. The identity of each phase usas determined by both X-ray and electron-diffraction techn~ques. Compositions of all three carbides were studied using the electron beam micro-probe analyzer and by unalyszs of electrolytically extracted residues. Optical and electron microscopy were employed in order that the time/temperature -dependent behavior of the carbides might be observed. Supplementary studies were completed on thin foils and oriented single crystals to determine the mor-phology and orientation relationship of each phase with that of the matrix. MAR-M~OO* is a high-temperature, creep-resistant superalloy designed for use in the as-cast condition. The "as-cast" microstructure consists of a solid-solution matrix, referred to as gamma (y), which contains a general, coherent precipitate of the inter-metallic Ni3(A1,Ti) referred to as gamma prime (?). As a result of dendritic segregation during solidification, a degenerate, spherulitic ? -?' eutectic constituent is present at the grain boundaries and the in-terdendritic regions, which is nucleated by the y on the dendrite tips. A primary carbide phase, a solidification product, is also present at the grain boundaries and in the interdendritic areas, and an additional carbide appears at the grain boundaries as a fine discontinuous precipitate. The alloy is particularly susceptible to heat treatment. For example, the mechanical properties of the columnar grained mater- ial are substantially improved by solution heat treatment, followed by an intermediate temperature age. Metallographic examination of heat-treated material reveals, however, that exposure to elevated temperatures has a marked effect on the microstructure of the alloy; in particular, it is observed that precipitation of considerable amounts of various carbide phases occur. The following investigation was carried out to determine the morphology, composition, and behavior of the carbides in Mar-Ma00 as an aid to the determination of their effect on the mechanical properties and stability of the alloy. THE PRIMARY MC CARBIDE The MC carbide phase appears in the interdendritic interstices and the grain boundaries. In directionally solidified Mar-M200 the carbide appears as very small particles in the chilled region, Fig. l(a), whereas in material less affected by the chill, it becomes larger and develops a dendritic morphology, Fig. 1(b). Step polishing of metallographic specimens from this region shows that in directionally solidified material the individual carbide dendrites are connected in a dendritic network within the metallic interdendritic interstices, whereas in material from the chilled region and in conventional Mar-M200 they are discontinuous, isolated dendrites. No orientation relationship exists between the primary carbide and the matrix.

Jan 1, 1968

By J. A. Hafford, J. K. Kerver, J. G. Richardson, P. M. Blair, J. S. Osoba

This paper presents the results of laboratory measurements of relative permeabilities to oil and gas on small core samples of reservoir rock by five methods, and describes the influences of such factors as boundary effect, hysteresis, and rate upon these measurements. The five methods used were the "Penn State," the "single core dynamic," the "gas drive," the "stationary liquid," and the "Hassler" techniques. In those methods in which the results are subject to error hecause of the boundary effect, the error may be minimized hy the use of high rates of flow. In order to avoid complexities introduced by hysteresis, it is necessary to approach each saturation unidirectionally. Observed deviations of relative permeabilities with rate can be explained as a manifestation of the boundary effect, and disappear as the boundary effect vanishes. The results indicate that all five methods yield essentially the same relative permeabilities to gas. Of the four methods applicable to the determination of relative permeability to oil, three, the Penn State, single core dynamic, and gas drive, gave relative permeabilities to oil which were in close agreement. The Hassler method gave relative permeabilities to oil which were consistently lower than the results obtained by the other methods. INTRODUCTION The relationship between the effective permeability of a reservoir rock to each of the fluids flowing through it and the corresponding fluid saturation is an important characteristic of the reservoir rock. Knowledge of this characteristic is and gas reservoirs and of the ultimate recovery to be expected extremely important in the prediction of the behavior of oil under various operating conditions. These effective permeabilities are usually expressed as the "relative permeability" to a fluid phase, defined as the ratio of the effective permeability to the permeability of the rock to a single phase at 100 per cent saturation. Relative permeability-saturation relations are not the same for all kinds of reservoir rock, but may vary from formation to formation, and within the different portions of a heterogeneous formation. In studying the performance of a specific reservoir, it is necessary, then, that the relative permeability characteristics of the individual portions of the reservoir be measured. These measurements may be made in the laboratory on small core samples from the reservoir. Various techniques have been proposed for the measurement in the laboratory of relative permeability-saturation relations. In varying degree, difficulties attend the use of all of the methods which have been proposed. It is the purpose of this paper to discuss the factors which influence the measurement of relative permeability, the difficulties encountered in several methods, and to present comparative results obtained by the use of various techniques. FACTORS WHICH INFLUENCE THE MEASUREMENT OF RELATIVE PERMEABILITY It is necessary that the relative permeability data measured in the laboratory yield the same relative permeability-saturation relationships that would govern the flow of fluids through the sample if it were to occupy its original position in the reservoir. Since the core sample upon which the laboratory measurements are made is not surrounded by similar core material as it was in the reservoir, an error in measuring the relative permeabilities may arise from the "boundary effect" which results from a discontinuity in capillary properties of the system at the effluent end of the core. Again, the rates of

Jan 1, 1951

By J. K. Kerver, J. S. Osoba, J. G. Richardson, P. M. Blair, J. A. Hafford

This paper presents the results of laboratory measurements of relative permeabilities to oil and gas on small core samples of reservoir rock by five methods, and describes the influences of such factors as boundary effect, hysteresis, and rate upon these measurements. The five methods used were the "Penn State," the "single core dynamic," the "gas drive," the "stationary liquid," and the "Hassler" techniques. In those methods in which the results are subject to error hecause of the boundary effect, the error may be minimized hy the use of high rates of flow. In order to avoid complexities introduced by hysteresis, it is necessary to approach each saturation unidirectionally. Observed deviations of relative permeabilities with rate can be explained as a manifestation of the boundary effect, and disappear as the boundary effect vanishes. The results indicate that all five methods yield essentially the same relative permeabilities to gas. Of the four methods applicable to the determination of relative permeability to oil, three, the Penn State, single core dynamic, and gas drive, gave relative permeabilities to oil which were in close agreement. The Hassler method gave relative permeabilities to oil which were consistently lower than the results obtained by the other methods. INTRODUCTION The relationship between the effective permeability of a reservoir rock to each of the fluids flowing through it and the corresponding fluid saturation is an important characteristic of the reservoir rock. Knowledge of this characteristic is and gas reservoirs and of the ultimate recovery to be expected extremely important in the prediction of the behavior of oil under various operating conditions. These effective permeabilities are usually expressed as the "relative permeability" to a fluid phase, defined as the ratio of the effective permeability to the permeability of the rock to a single phase at 100 per cent saturation. Relative permeability-saturation relations are not the same for all kinds of reservoir rock, but may vary from formation to formation, and within the different portions of a heterogeneous formation. In studying the performance of a specific reservoir, it is necessary, then, that the relative permeability characteristics of the individual portions of the reservoir be measured. These measurements may be made in the laboratory on small core samples from the reservoir. Various techniques have been proposed for the measurement in the laboratory of relative permeability-saturation relations. In varying degree, difficulties attend the use of all of the methods which have been proposed. It is the purpose of this paper to discuss the factors which influence the measurement of relative permeability, the difficulties encountered in several methods, and to present comparative results obtained by the use of various techniques. FACTORS WHICH INFLUENCE THE MEASUREMENT OF RELATIVE PERMEABILITY It is necessary that the relative permeability data measured in the laboratory yield the same relative permeability-saturation relationships that would govern the flow of fluids through the sample if it were to occupy its original position in the reservoir. Since the core sample upon which the laboratory measurements are made is not surrounded by similar core material as it was in the reservoir, an error in measuring the relative permeabilities may arise from the "boundary effect" which results from a discontinuity in capillary properties of the system at the effluent end of the core. Again, the rates of

Jan 1, 1951

By C Gunther

In the examination of an undeveloped prospect a decision must be arrived at from an inspection of the outcrops and the exposures in a few shallow pits. Prospects that are offered for sale rarely expose any important quantity of good ore, work having usually been stopped when the immediate exploration no longer yielded favorable results. It should be borne in mind, furthermore, that a great majority of prospects have been examined many times, and if of conspicuous promise, would have been acquired for development. In most cases the problem for the engineer, therefore, is to discover the traces of a valuable mineralization that has disappeared through solution, or the conditions that indicate the possibility, or probability, of underlying secondary enrichments. The available data being meager, every feature should be the subject of careful study-the condition of the outcrop, the structural relationships, the associations of minerals, the alterations of wall rocks, the chances for underlying enrichments, and so forth, as well as the actual assay value of the material exposed. It is frequently advisable to spend the time and money necessary to have trenches dug at various significant points along a promising outcrop; such exposures, even if the depth attained is slight, often disclose conditions that are not apparent at the actual surface, as for example, the existence of soft minerals and the distribution of the various minerals through the mass of the deposit. Trenches also permit samples to be taken from points that were not accessible during former examinations. Strong, persistent outcrops of uniform width may be taken to indicate the probable size and character of the underlying vein,

Jan 1, 1932