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By S. R. Mitchell, M. C. Fuerstenau, A. M. Gaudin

The two principal attributes of a thickener pulp are its settling rate and the ultimate pulp density of the thickened mud. Testing for evaluation of thickening attributes of a pulp has usually been done batch-wise by placing the pulp in a one-liter glass graduated cylinder and noting the position of the boundary between clear liquor and mud as a function of time. Refinements in testing have included repulping a thickened mud to various dilutions and evaluating the settling rate on these various repulped muds. This is considered to make possible an estimate of the settling rate as a function of pulp density and therefore to pinpoint the slowest settling pulp which ought to be critical from the standpoint of thickener plant design. Finally, tests are sometimes made with model-size continuous thickeners of arbitrary size. In batch tests it is generally accepted that the behavior of a pulp is described by a curve such as the one shown in Fig. 1, in which the position of the boundary between clear liquor and mud (the mudline) is plotted against time. It has also been assumed that the initial settling rate (the slope of the line segment AB) is descriptive of the pulp and independent of the size and shape of the container. Where the settling rate is slower and clearly a function of time (portion CD of the settling curve), it has been assumed that the data are not of much use because of the intrusion of compacting phenomena. The next important datum is the height, PE, which is a measure of the so-called ultimate pulp density. This quantity is assumed to be characteristic of the pulp and independent of the container.

Jan 6, 1959

By J. E. Burke, Y. G. Shiau

SEVERAL attempts have been made to account for the fact that grains in a fully recrystallized metal will coarsen on annealing Two fundamentally different hypotheses have been advanced; with several variations of each. One school considers that the cause of grain growth is the surface energy of the grain boundary The theory of Jeffries1 that grain size and grain size contrast control growth is an example The second school considers the primary cause to be a difference in the lattice energy on either side of the grain boundary The more perfect grains are considered to grow at the expense of their less perfect neighbors, with a decrease in free energy, and a consequent increase in the stability of the system. Burgers2 presents the case for the strain or lattice imperfection theory of grain growth quite completely The latter theory is attractive, since there is no doubt that differences in lattice energy or lattice perfection can cause grain boundary migration A recrystallization nucleus grows for this reason as was beautifully demonstrated by van Arkel and Ploos van Amstel3 Although it is generally stated that grain growth does not precede recrystallization, several workers4,5 have shown that small strains may induce a single crystal in an aggregate to grow, or at least may cause some' grain boundary migration The origin and nature of the imperfections that are considered to be responsible for normal grain growth have never been clearly described, but it is generally agreed that they are a consequence of the difficulty of atomic reorientation in the solid state, and that they do not seriously differ from the type of imperfection that-can be introduced by mechanical deformation An object of the present work was to determine whether the introduction of mechanical deformation would cause grain growth in a specimen which would not otherwise show it under the conditions used It was also planned to determine the effect of such deformation the rate of growth in a specimen which would show - growth in the unstrained condition Recently Maddigan and Blank6 have indicated that slightly strained specimens of alpha brass can undergo considerable growth prior to recrystallization if annealed at low temperatures French7 has reported that at deformations less than 17 pct it is very difficult to detect the beginning of recrystallization in the same material. It was therefore planned to broaden this work to include a complete study of the microscopic behavior of alpha brass under conditions of temperature, time, grain size and deformation such that recrystallization would not occur or would occur to only a small extent EXPERIMENTAL PROCEDURE The brass was prepared by melting cathode copper and commercially pure zinc

Jan 1, 1947

By R. A. Vandermeer, Paul Gordon

On the basis of a unified concept, theoretical erPressions for grain boundary migration in recrys-tallization are derzved for impurity-controlled and impurity-independent migration. The expression in the former case is analogous to that Previously derived by Lucke and Detert, and in the latter is shown to be equivalent to that usually obtained on the basis of absolute reaction rate theory. The equations are tested with quantitative experimental data for boundary migration obtained for the recrystallization of poly crystalline zone-refined alumimnz and for binary "alloys" of this aluminum with 0.00021, 0.00043, 0.0017, 0.0034, 0.0068, 0.0124, and 0.0256 at. pct Cu, respectively. All the essential characteristics of the e@erimentally determined boundary migration rates check both qualitatively ard quantitatively with the predictions of the theoretical equations. THE rates of transformations are customarily analyzed phenomenologically in terms of the two component rates—N, the rate of nucleation and, G, the rate of growth of the nuclei. The scientific aim of both theory and experiment is to describe the fundamental atomic phemmena involved in these two component processes with the hope that parameters calculated from theoretical equations will check those found experimentally. In solid state transformations, the theoretical and experimental problems are both generally of almost prohibitive complexity, for in addition to changes in composition and in such properties as density which may accompany transformations in amorphous, nonrigid materials, transformations in crystalline substances also involve structural changes, crystal reorientations, and the development of stresses. In studying such transformations it thus becomes; highly desirable, if not essential, to focus on a transformation and a set of conditions which minimize the number of active variables. This principle has been applied with considerable success by Cohen and his associates' in their evaluation of nucleation theories using the martensite transformation as the basis of study. A similar possibility exists for the evaluation of growth theories by the use of recrystallization after cold-deforming. If an unalloyed metal is employed as the subject of investigation, the recrystallization transformation involves basically only a change in strain-conditions and orientations. In spite of this possible simplilfication, however, until recently little quantitative success has attended attempts to correlate recrystal1ization parameters measured experimentally with those calculated theoretically. It seems highly probable that this lack of success may be attributed, both in the experimental and theoretical treatments, to one or more of the following factors: a) conditions have usually been studied under which apparently* both nucleation and growth are active;

Jan 1, 1962

By R. W. Ph. D. Raymond, Anton Filers, O. H. Hahn

THIS paper will treat of such works only as beneficiate ores directly in the mining districts. And when it is said that more than twenty furnaces exist in Utah, about as many in Nevada, five in Montana, and four in Cerro Gordo, Inyo County, California, it is obvious that a business so extended deserves attention. Wide apart as these different works are located, they have nevertheless to deal in nearly every case with the same or very similar circumstances and conditions, so that, with very few exceptions, virtually the same system of smelting is followed in all these establishments. This is the so-called method of reduction and precipitation in blast-furnaces. As the principal reasons for the employment of a blast-furnace process are to be considered : the low percentage of lead in the ores, the high price of the only available fuel, charcoal, and the exorbitant rates demanded for labor. The reasons why the reduction and precipitation process is preferred to a roasting, reduction, and precipitation process are the high prices of labor and materials, and the preponderance of oxidized ores over sulphurets, though in some cases the latter are quite abundant. The weight of these reasons will be better understood when the character of the ores to be treated and the object of the smelting are more minutely stated. The ores are in nearly all cases a preponderating mass of oxidized lead ores, such as cerussite, anglesite, and leadhillite, in which nests and nodules of undecomposed galena occur. Associated with these are : in Eureka, Nevada, arseniate of iron and arsenical pyrites, hydrated oxide of iron, quartz, and calcareous clay ; in Little Cottonwood Canyon and American Fork, Utah, iron oxide, and in some cases a combination of antimony, the nature of which I have not ascertained; also dolomite and quartz in widely varying proportions; in Bingham Canyon, Utah, only quartz and comparatively little oxide of iron, or iron sulphurets; in Cerro Gordo, California, oxide of iron, iron pyrites, antimonial compounds, copper ores, and, as gangue, carbonate of lime and quartz. In Argenta, Montana, occur, besides the above-named lead ores, pyromorphite, and molybdate of lead. The preponderating gangue of the Argenta ores is quartz, and there is here a larger proportion of galena than elsewhere in the West. In most of the localities named, the lead ores themselves contain sufficient silver to render its separation from the ore the main object of the smelting; but in some of the districts, and especially in Montana, the lead ores serve only to furnish the extracting agent for the silver of true quartzose silver ores, which at the same time contain a sufficient percentage of lead to make amalgamation impracticable. They are therefore beneficiated by smelting, although the lead itself has no market value.

Jan 1, 1873

By R. Dawson Hall

The stresses in the simplest structures are often those we find most difficult to analyze. The most complex condition in mine stresses is found in simple tunnels where the roof, the sides, and the floor are a monolith. The functions of the parts are like the parts themselves not distinct and spccialized, and the problems to be solved are like those in a metal structure with riveted joints or a redundancy of bars. This difficulty explains perhaps why the condition has not been treated. But just because it cannot be discussed in its entirety is no reason why it should be treated as an action of parts with spccialized functions as a roof beam with supports and a foundation. The problern cannot be ignored on the ground that it is not of sufficient importance to warrant careful consideration, because conditions of complete monolithism, of which the tunnel is the type, are found materially unchanged in room-and-pillar and in longwall work. This unity between roof, sides, and floor, which to the coal miner is a difficult conception, really deserves a scientific appellation, and perhaps holoid (from holos, whole, and eidos, form) will serve the purpose as well as any other. In a simple tunnel the roof, the sides, and the floor form integral parts of one and the same structure, and the distortion of one cannot be conceived without a consequent strain in the others. Thus when the roof of the tunnel droops by reason of its weight, the upper parts of the sides are drawn in becausc they are integrally connected with the roof and must approach each other whenever, by the sagging of the roof, the distance between any two points in it is diminished. (See Fig. 1.) Thc sides in their turn operate on the floor of the holoid structure, producing a tensile stress. The writer has always been impressed with the value of soap as a means of illustrating the action of mine stresses. With that idea in mind' a cake of naphtha soap measuring 43/8 by 2¼ by 19i in. was taken and a tunnel was made through it 13/4 in. long, 21/2 in. wide and 1¼ in. high. (See Fig. 2.) A load was then placed at the mid-span of the tunnel. Eventually, the upper bar, or "roof," broke at the

Jan 1, 1916

By R. B. Kelly, Paul Martin

Central Texas added 76 producing oil and gas wells during the year, abandoned 378 wells in the same period, and produced 10,359,905 bbl. of oil in the 12 months under consideration. The oil production represents a decline of only 3 per cent as compared to 1934, but it must be remembered that much new production was added during the year. The activity in new work centered in Frio, Bexar, Williamson and Cald-well counties, with development in the Pearsall, Von Ormy and Byersville fields taking first importance. New discoveries in 1935 were confined to Pearsall area of Frio County and an extension to the Darst Creek field in Guadalupe County. The Red Lake field, in eastern Freestone County, proved itself of importance from the standpoint of a gas reserve but no oil production has yet been obtained. In Bexar County, the Von Ormy field, in which the discovery well was drilled early in 1934, completed 22 oil producers during the year. (A map of Central Texas showing location of oil and gas fields was published in Volume 114 of the A.I.M.E. Transactions.) New Fields Pearsal1.—The Amerada Petroleum Corporation, in developing its 60,000-acre block in Frio County, has definitely proved the existence of commercial oil production in four separate horizons; namely, the Navarro, the Austin Chalk, the Buda and the Georgetown. The discovery well, a two million cubic foot gas well, was tompleted in 1934. A test of the Trinity sand at 10,050 ft. found salt water but later was plugged back and finished as an oil well in the Navarro sand. Most recent of their discoveries has been in the Austin Chalk at a depth of 5666 ft., where a 24-hr. gage through 1-in. choke showed 2640 bbl. of pipe line oil. The oil has a gravity of 28.0" A.P.I. and is brownish in color. Because of lack of pipe lines in the area, the wells are produced only for short periods of time, and it is predicted that development will be slow until the district is entered by pipe line purchasing companies. Von Ormy.—In March, 1934, Umbren et al. completed their Wentz

Jan 1, 1936

By Paul Martin, R. B. Kelly

Central Texas added 76 producing oil and gas wells during the year, abandoned 378 wells in the same period, and produced 10,359,905 bbl. of oil in the 12 months under consideration. The oil production represents a decline of only 3 per cent as compared to 1934, but it must be remembered that much new production was added during the year. The activity in new work centered in Frio, Bexar, Williamson and Cald-well counties, with development in the Pearsall, Von Ormy and Byersville fields taking first importance. New discoveries in 1935 were confined to Pearsall area of Frio County and an extension to the Darst Creek field in Guadalupe County. The Red Lake field, in eastern Freestone County, proved itself of importance from the standpoint of a gas reserve but no oil production has yet been obtained. In Bexar County, the Von Ormy field, in which the discovery well was drilled early in 1934, completed 22 oil producers during the year. (A map of Central Texas showing location of oil and gas fields was published in Volume 114 of the A.I.M.E. Transactions.) New Fields Pearsal1.—The Amerada Petroleum Corporation, in developing its 60,000-acre block in Frio County, has definitely proved the existence of commercial oil production in four separate horizons; namely, the Navarro, the Austin Chalk, the Buda and the Georgetown. The discovery well, a two million cubic foot gas well, was tompleted in 1934. A test of the Trinity sand at 10,050 ft. found salt water but later was plugged back and finished as an oil well in the Navarro sand. Most recent of their discoveries has been in the Austin Chalk at a depth of 5666 ft., where a 24-hr. gage through 1-in. choke showed 2640 bbl. of pipe line oil. The oil has a gravity of 28.0" A.P.I. and is brownish in color. Because of lack of pipe lines in the area, the wells are produced only for short periods of time, and it is predicted that development will be slow until the district is entered by pipe line purchasing companies. Von Ormy.—In March, 1934, Umbren et al. completed their Wentz

Jan 1, 1936

By G. Wranglen

On account of the possibility of isolating carbides in steel it is generally assumed that the electrode potential of iron carbide is more noble than that of ferrite.1,2,3,4,5 Differences from 0.032 V1 to 0.4 V4 have been recorded. However, it is important to realize that the more noble behavior of cementite in relation to ferrite is not an issue of thermodynamics but of reaction kinetics. Theoretically, cementite is less noble than ferrite, which is a direct consequence of its thermo-dynamic instability. With the value ?F°298 = +4700 cal per mol for the free energy of formation of cementite6 it is easily calculated that the electrode

Jan 1, 1950

By J. P. Hirth, C. S. Hartley

A simple graphical technique is presented for rapidly determining the ratio of resolved shear stress on slip systems in single crystals to the applied stress (Schmid factor) for various simple states of stress. Master plots are presented which, when used in conjunction with an appropriate stereo-graphic projection, allow one to determine the Schmid factor for all slip systems in a crystal of given orientation. It is shown that one such plot suffices for simple tension or compression, flex-ural bending, and biaxial compression, while a combination of two different plots must be used for torsion and simple shear. STUDIES of the deformation behavior of single crystals are most valuable when the applied stresses are resolved onto the various slip systems of the crystal. A careful study of the available slip systems and proper selection of the state of stress used and the specimen orientation can then yield quantitative information about the probability of specific dislocation reactions, the strength of barriers to plastic flow, and the mechanisms of yielding and flow in general. It is the purpose of this work to analyze some common states of stress used in deformation studies and to present a simplified way of determining for these cases the ratio of the resolved shear stress on the slip systems to the applied stress (Schmid factor). I) CALCULATIONS We first define two orthogonal coordinate systems: one based on the specimen geometry (a right circular cylinder of radius, R, is considered here) and one based on the particular slip system of interest. The unit vectors and angles specifying the two coordinate systems and the relationship between them are listed in Table I. The relationships among the various angles and unit vectors are shown on a stereographic projection in Fig. 1. The transformation matrix between the (XI X2 X3) and (x'1 x'2 x'3) system is x1 x2 x3 X'1 a11 al2 a13 x'2 a21 a22 a23 x'9 a31 a32 a33 where in this case the direction cosines aij are given by a11 a12 a13 aij = a21 a22 a23 a31 a32 a33 sin 0 cos F cos 0 sin F cos 9 = -cos 0 cos F sin 0 sin F sin 6 [1] 0 -sin F cos (p In terms of Eq. [I.], the stresses sij, referred to the slip system, are determined from oij, referred to the specimen axes, by1,2

Jan 1, 1965

By C. W. Reith

The development of production in West Texas during the year 1933 was largely confined to the expansion of proven areas, especially Ward County, Iatan and North Winkler. Wildcat activity was at a comparatively low ebb and resulted only in discoveries of probable minor importance in Ector County. The interest shown in deep wildcatting to test beds of pre-Permian age was a new development, which should soon throw light on the possibilities of deeper production from the present producing fields. The important pre-Permian tests of the year were: 1. Stanolind Oil and Gas Co., Todd No. 1, a unitized test, in north central Crockett County on a probable continuation of the Big Lake trend. The well encountered several showings of oil and penetrated an Ordovician section very similar to the productive zones at Big Lake, but was abandoned when sulfur water was encountered at 8041 feet. 2. Gulf Production Co., McElroy No. 103, in the McElroy Field, Upton County. The well was drilling at 8553 ft. at the close of the year in beds of probable pre-Permian age. The test is an important one because it should prove or disprove deep production in the Church-Fields-McElroy pools and also throw geologic light on the deep possibilities of other fields in the western part of the Permian Basin. 3. Humble Oil and Refining Co., White and Baker No. 1, in Pecos County, about 11 miles west of the Yates field. The well is on a nonproductive Permian high and should indicate the deep possibilities of the Yates field. At the end of the year, drilling had progressed to 7200 ft., where beds of pre-Permian age are believed to have been penetrated. The major fields in West Texas, in which present-day proration had its inception, were produced under increased restrictions. A date of importance in the proration history of the area was $ept. 8, 1933, when the Railroad Commission issued an order placing all producing wells under proration. The severe reductions in total outlet made during 1933 were well compensated for by a more than threefold increase in the price of crude oil. Acid treatment was one of the general engineering developments of interest. The work had not progressed sufficie~ltly at the close of 1933

Jan 1, 1934

By J. Chipman, H. Towers, M. Paris

A simple radioactive tracer technique is used to measure the diffusion coefficient of calcium ion in molten slags. In a slag of 40 pct Ca0-40 pct Si0,-20 pct Al203, Dc " at 1450°C is 1.3x10-6 cm' sec-'. THE application of the principles of thermodynamics to steel and iron making problems has proved so fruitful that the kinetic approach has tended to be neglected. It seems probable that in some reactions the rate-determining step is the dif-fusivity of the reactants or of the products. But knowledge of the diffusion coefficients of the constituents of liquid slag and metal is singularly lacking. The present work was undertaken as a first step toward supplying such data for slags. Furthermore, any additional information on the physical properties of liquid slags might be expected to help in elucidating their structure. It is essentially a preliminary investigation, the course of which was determined more by the necessity of establishing a method than by the immediate intrinsic interest of the results. For example, the selection of calcium ion to be studied was dictated by the suitability of the isotope Ca45 in that it is a simple emitter with a long half-life. Of the other ions commonly encountered in slags, the isotopes of iron and manganese have relatively complex radiations as well as the normal disadvantage of requiring control of the oxygen potential of the atmosphere; Mg27 and Al29 have half-lives measured only in minutes; Si3' has a simple decay process but its half-life of 2.8 hr is too short for preliminary studies; the only useful oxygen isotope is the stable O18; and there remain only sulphur and phosphorus both of which have suitable isotopes but were rejected as being of less fundamental interest than calcium. Similarly a lime-alumina- silica slag was used in preference to calcium silicate primarily because of its low melting point and its capacity to form a glass on fairly rapid cooling. Literature Review Very few studies of diffusion in liquid silicate systems have been reported. In order to determine the origin of diopside inclusions in felspathic rocks, Bowen1 investigated the diffusion between diopside and various mixtures of albite and anorthite. Platinum crucibles were used with diopside, the heavier of the two liquids, forming the lower half of the cell and diffusion taking place against gravity. Change in concentration along the diffusion path was found by measuring the refractive index of the quenched glass. Nearly thirty years later McCallum and Barrett2 used essentially the same method to determine the diffusion coefficient of lime in lime-alumina-silica slags. In this case the interest was to find the rate-determining step in the process of slag attack on refractory materials. In an investigation of the kinetics of the sulphur reaction, Derge, Philbrook, and Goldman8 determined the diffusion coefficient of sulphur in a typical blast furnace slag by the simple procedure of melting a slag containing 2 pct S over an identical slag sulphur-free. They make no claim to a high degree of accuracy but suggest that D, is of the order of 10-6 cm2 sec-l. Other high temperature liquid diffusion studies have been concerned with metals. Holbrook, Furnas, and Joseph4 determined the diffusion coefficients of silicon, phosphorus, sulphur, manganese, and carbon in liquid iron by immersing a small carbon crucible containing pure iron-carbon alloy in a large vessel containing iron with a high concentration of the particular element. Their results were confirmed by Paschke and Hauttmann5 using a similar method. Diffusion coefficients in silicates in the glassy state have been studied by Johnson, Bristow, and Blau6 Both Na24 and Ca45 were used as tracers but only the

Jan 1, 1954

By N. A. Parlee, A. E. Lord

Measurements of the solubility of lead in liquid iron were made at 1550°, 1600°, 1650°, and 1700°C using two different methods, i.e., 1) liquid iron-liquid lead equilibration and 2) liquid iron-lead vapor equilibration. LEAD was long considered insoluble in liquid iron1. Today steels containing 0.15 to 0.35 pct Pb are used. One laboratory has found a solubility of about 0.5 pet in the 1600°C range. Recently Miller and Elliott2 gave 0.60 pct as the result of one determillation at 1540°C. Because these findings resulted from the

Jan 1, 1961

By N. Brown

IT has been observed that a hexagonal-close-packed crystal will undergo the same macroscopic displacements as an isotropic material if the basal plane is perpendicular to the axis of twist.&apos; Other orientations may produce both bending and twisting, but this analysis will be confined to pure torsion of a right circular cylinder. The z axis, the axis of twist, and the specimen axis are coincident. The displacements are given by Uq = rz, Ur = Uz = 0 [1] where 4 is the angle of twist per unit length. This requires rotational slip, as discussed by Frank&apos; and Wilman, which may be observed readily. The relative rotation of adjoining slip planes is simply produced by a movement of a planar grid of screw dislocations."." The screw dislocations are of the same sign and they move radially inward. For hexagonal-close-packed metals, the grid is hexagonal and the screw dislocations lie in the < 2110 > directions. The displacement of a point is the resultant of two displacements produced by intersecting screws sweeping over the point. The dislocations must pass over the point (r, o) in such a manner that its resultant displacement corresponds to the observed macroscopic displacement. If 6&apos; is measured from the [1010] direction, then for 0 < ? < ~/3, only the [1210] and 121101 type screw dislocations are needed to produce the required displacement. If n1 screws of type [1210] and n2 of type [2110] pass over a point, then, in order that Ur = 0 n, sin ? - n2 sin (/3 — 6&apos;) = 0. [2] If the tangential displacement is to be independent of 0, then n1 cos ? + n2cos (/3 —?) = N [3] where N is independent of ? and thus depends only on r. Nb is the tangential displacement where b is the Burgers vector. Since U? is a linear function of r, then N must be a linear function of r. If a2 is the outer radius and a, is the inner radius to which the plastic deformation has extended, then N = Nm2 r-a1 [4] This function meets the conditions that at

Jan 1, 1956

By R. J. Tailleur, M. Rosenberg

Oil well drilling muds prepared with lubricating aids such as oil, graphite or mica will not produce a sufficiently strong protective lubricant film for the bit bearing surfaces under high load conditions encountered in drilling operations. Consequently, the damage to the bearing surfaces resulting from the absence of such a film frequently results in a shortening of the drill bit life. Several different types of extreme pressure lubricating additives for use in muds have been developed. These arlrlitives are capable of providing a protective lubricating film for bearing surfaces subjected to high load pressures. A modified version of the Timken lubricant tester, an instrument commonly used for testing the extreme pressure lubricating properties of oils, is used for measuring and controlling the lubricating qualities of the mud. Comparison tests made in the laboratory with 55/8-in. tricone bits drilling on steel plates immersed in extreme pressure lubricating muds and conventional muds showed that the bearing life of those bits tested in the lrrbricating mud was three to four times greater than obtained with conventional muds. Drilling tests made with extreme pressure lubricating muds in West Texas increased over-all bit life three to fourfold, reduced drilling torque and wear on drill pipe and drill collars. INTRODUCTION Roller bit cones contain roller, ball and journal-type bearings that are subjected to very heavy loading during drilling operations in which the only lubricant available for these bearings is either water or drilling mud. These bearings must be able to operate satisfac- torily in order for the cutting structures on the surface of the cones to be fully utilized. Frequently, the bearings wear to the point that the cones freeze and the bit must be pulled before the cutting structures on the cones become worn. In some instances the bearings continue to turn with severe wear but the cones, which are held on the bit by the bearings, drop off; and this causes an expensive fishing job. In other instances the bearings wear to the point that the cones pinch in causing an undergauge hole and delays to ream the hole. The advantage of increasing bit bearing life is self-evident. Because of inability to control the internal wear of bits while drilling, it was felt that improvement of the lubricating qualities of the circulating mud would be helpful. However, the often-discussed lubricating property attributed to muds has been a rather vague and intangible one. The literature has implied that the oil-emulsion muds are more effective lubricants than non-emulsion muds. Actually, there has been no direct method of measuring the lubricating property of muds which would indicate that one mud was better than another; there has been no way to determine whether the lubricating property of any mud was adequate. Furthermore, in comparing lubricating properties of muds, two qualities should be considered—the coefficient of friction and the extreme pressure lubricating qualities. For example, graphite can reduce the coefficient of friction, but does not provide a strong enough lubricating film to protect bit bearings subjected to high loads. The primary object of the investigation reported herein was to find a method for prolonging the bearing life of drill bits; and considering the heavy loads used in drilling, it was felt necessary to find both a method of measuring lubricating properties under high load conditions and methods of establishing effective lubrication under these conditions. Extreme pressure lubrication deals with that realm of lubrication where metal surfaces are in rubbing contact with each other under very high pressures. These pressures may be quite high, as for example,

By Walter R. Hibbard, Harold Margolin

DURING preliminary tests on the aging of a Cu-plus 5 pct Ag alloy,&apos; a specimen which had been overaged 24 hr at 550°C was annealed in a nitrogen-hydrogen atmosphere first for 2 hr and then for an additional 28 hr at 600°C. After each anneal the specimen was cooled to room temperature in about ½ hr and X-ray photograms were made. The first film, Fig. la, revealed two sets of copper-base lines, one intense and corresponding to the parameter at 550°C, the other fainter and shifted away from the beam, corresponding to the larger parameter at 600°C (see arrows). The 30-hr film, Fig. lb, revealed the same two sets of copper-base lines with a reversal of intensity. In neither case do the copper lines form a broad band which would be indicative of a range of compositions. This phenomenon is thus a "discontinuous" type of solution. A similar phenomenon was observed in a Ag-rich Cu-Ag alloy.&apos; Finlay and Hibbard9 have suggested that directional rather than random solution of precipitate occurs in some alloys. Conceivably, for Cu-Ag alloys, the matrix-transition-precipitate precipitation sequence is reversible for the re-solution of the precipitate caused by rapidly raising the annealing temperature of an overaged specimen. A copper-base transition structure supersaturated with solute might be formed around the precipitate as it dissolves, thus obviating the necessity for a gradually changing solute composition of the matrix. The solute atoms then might be transferred rapidly and locally from the transition to the matrix phase in the proper amount and at the proper location to obtain directly the new ex- panded solid solution. The theory implies a minimum of diEusion of solute in the matrix (i.e., no significant range of matrix composition) and possibly suggests that the composition of the transition structure will vary with the conditions of re-solution. A transition copper phase found in aged Cu-Ag alloys1 might fulfill this function. Evidence regarding this suggestion could be obtained in Cu-Ag alloys by overaging a specimen until no trace of the expanded copper lattice is present and then subjecting the specimen to a retrogression treatment. Re-appearance of the transition copper phase would confirm the theory. Additional details could be secured by varying both aging and retrogression temperatures. References &apos;H. Margolin and W. R. Hibbard, Jr.: Effect of Ternary Additions on the Age Hardening of a Copper-Silver Alloy. Trans. AIME (1951) 191, p. 174; Journal of Metals (Feb. 1951) TP 3002E. 2 W. Ageew, M. Hansen, and G. Sachs: Decomposition and Changes in Properties of Super-saturated Silver-Copper Alloys. Ztsch. Physik (1930) 66, p. 350. 3W. L. Finlay and W. R. Hibbard, Jr.: Some Effects of Applied Stresses on Precipitation Phenomena. Trans. AIME (1949) 180, p. 255; Metals Technology (Sept.

Jan 1, 1952

By John R. Anderson, Michael B. Bever

CARBON may affect the alloys of copper in several ways. Provided an alloying element does not oxidize preferentially, even minute quantities of carbon dissolved in liquid alloys of high copper content will form insoluble carbon oxide gases under oxidizing conditions. Gas porosity in castings of high-copper alloys can originate in this way. In certain alloys of low copper content carbon may have considerable solubility and may be an effective deoxidizer. In these alloys carbon will tend to suppress porosity. Carbon that is dissolved in the molten alloy is likely to be retained in the solidified metal. The effects of carbon on the physical properties of the metal are determined by the form in which it is present. Depending on the alloying elements and also on the cooling rate, carbon may precipitate as graphite, may form a carbide or may remain in solid solution on cooling. As solid copper does not dissolve a measurable amount of carbon, a carbon-bearing solid solution can occur only if the copper is alloyed with a large excess of an element that forms such a solution. The effect of graphite or of carbides on the properties of an alloy will depend on the size and distribution of the precipitated particles. As Hensel pointed out in discussion,1 the formation of an alloy carbide may interfere with the age-hardening properties of a copper alloy. One would also expect that the presence of carbides or of graphite will under certain conditions promote corrosion or high-temperature failure in nonferrous alloys. Since carbon has an effect on the soundness of castings and affects the structure and behavior of solid copper alloys, its solubility in the liquid alloys is of practical importance. The isothermal change of carbon solubility with alloy composition is of interest from a theoretical standpoint. The binary alloys of copper with manganese and with nickel are used industrially and serve as a base for more complex alloys. The solubility of carbon in each of these metals is known, but its solubility in their alloys has not been determined. EARLIER DATA The solubility of carbon in molten pure copper is about 0.0001 pct at 1100 °C and 0.0004 pct at 1475°C.1 Various authors2-6 have published data on the solubility of carbon in molten manganese. There is agreement on a value of about 6.7 pct in the temperature range 1217° to 1245°C. This solubility value corresponds to the formula Mn3C. It increases very little with increasing temperature. Corson7 states that carbon is soluble in copper-manganese alloys and that the

Jan 1, 1947

By C. A. Hartnagel

In 1939 the production of crude oil in New York totaled 5,105,000 bbl. This marks the third consecutive year production of crude oil has exceeded 5,000,000 bbl. and only once has this total been surpassed—in the year 1882, three years after the discovery of oil in Allegany County, when the annual production was more than 6,000,000 barrels. The most gratifying feature of the industry was the increased demand for lubricants, which resulted in advanced prices for crude. From a price at the beginning of the year of $1.68 per barrel, six advances totaling 82c brought the year&apos;s closing to $2.50 per barrel. A further increase in price on Jan. 1, 1940, to $2.75 per barrel places the local industry in a strong position for the year&apos;s operations. Most of the oil production of the state is now obtained by water-flooding, and the industry is practically stabilized. No new pools have been discovered in over 25 years, and border drilling indicates little prospect of extending the boundaries of the fields beyond their present limits. Deep drilling to the Oriskany sandstone in and close to the present oil fields hay failed to find oil in substantial amounts. Altogether, the oil pools of New York have produced during the 60 years that they have been exploited approximately 125,000,000 bbl. of oil. Following the flush production of 1882, the annual production gradually dccrcased and the year 1912 marked an all-time low of only 782,000 bbl. In 1919, as a result of flooding operations, a definite upward trend in oil production was recorded. During that year also the production of oil by water-flooding methods as approved by Legislative action. In the 21-yr. period beginning with 1919, oil production in the state ha.: totaled 60,338,000 bbl. Thus it will be seen that by the aid of flooding methods nearly as much oil has been produced in the last 21 yr. as in the preceding 40 yr., although the Iatter period included the flush production in 1882. As there is little hope of extending the area of the present producing oil fields of the state, producers and refiners are concerned regarding the future life of the fields. It is encouraging to observe that earlier esti- Published by permission of Director of New York State Museum, Albany, N. P. Summarized at meeting; manuscript received at the office of the Institute March 20. 1940.

Jan 1, 1940

By C. A. Hartnagel

In 1939 the production of crude oil in New York totaled 5,105,000 bbl. This marks the third consecutive year production of crude oil has exceeded 5,000,000 bbl. and only once has this total been surpassed—in the year 1882, three years after the discovery of oil in Allegany County, when the annual production was more than 6,000,000 barrels. The most gratifying feature of the industry was the increased demand for lubricants, which resulted in advanced prices for crude. From a price at the beginning of the year of $1.68 per barrel, six advances totaling 82c brought the year&apos;s closing to $2.50 per barrel. A further increase in price on Jan. 1, 1940, to $2.75 per barrel places the local industry in a strong position for the year&apos;s operations. Most of the oil production of the state is now obtained by water-flooding, and the industry is practically stabilized. No new pools have been discovered in over 25 years, and border drilling indicates little prospect of extending the boundaries of the fields beyond their present limits. Deep drilling to the Oriskany sandstone in and close to the present oil fields hay failed to find oil in substantial amounts. Altogether, the oil pools of New York have produced during the 60 years that they have been exploited approximately 125,000,000 bbl. of oil. Following the flush production of 1882, the annual production gradually dccrcased and the year 1912 marked an all-time low of only 782,000 bbl. In 1919, as a result of flooding operations, a definite upward trend in oil production was recorded. During that year also the production of oil by water-flooding methods as approved by Legislative action. In the 21-yr. period beginning with 1919, oil production in the state ha.: totaled 60,338,000 bbl. Thus it will be seen that by the aid of flooding methods nearly as much oil has been produced in the last 21 yr. as in the preceding 40 yr., although the Iatter period included the flush production in 1882. As there is little hope of extending the area of the present producing oil fields of the state, producers and refiners are concerned regarding the future life of the fields. It is encouraging to observe that earlier esti- Published by permission of Director of New York State Museum, Albany, N. P. Summarized at meeting; manuscript received at the office of the Institute March 20. 1940.

Jan 1, 1940

By J. A. Bownocker

THE production of oil in Ohio, in 1924, was characterized by no marked or surprising change. Low prices and the absence of promising territory made the year quiet. As is well. known, Ohio has reached a state of "settled production," and the most that can be expected for the ensuing few years is to maintain the output at approximately the present figure 1921 7,335,000 1922 6,781,000 1923 7,085,000 Geographically, the Ohio fields may be divided into three areas, each of which gets its main supply of oil from a different stratigraphic horizon.

Jan 3, 1925

By George F. Sowers

THE geophysical methods of exploration employed so extensively in mining and petroleum investigations are now being used in civil engineering. Requirements differ from those of mineral ex- ploration and therefore modified techniques have been developed. The civil engineer is primarily interested in the uppermost soil and rock strata. In highway engineering the materials affecting design and construction may be found within 15 or 20 ft of ground surface, and data on soils and rocks is seldom needed for more than a depth of 100 ft even for the heaviest structures.

Jan 1, 1954