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By O. C. Blade

The southeastern region of the United States is becoming more important as a petroleum-producing area, and it is receiving increasing attention from oil operators. In 1948 total production of crude oil from six southeastern States - Alabama, Florida, Kentucky, Mississippi, Tennessee, and Virginia - was 55,244,000 barrels, which represents 2.7 percent of the Nation's output during that year. Kentucky and Tennessee have produced crude oil since the early days of the industry, but the remaining four States have had production only few years. Data on annual production of crude petroleum in the six States are given in table 1.

Jan 1, 1950

By D. H. Davis

HAND picking was the earliest form of coal preparation, first practiced to improve the outward appearance of the coal being loaded and to remove any pieces that might appear objectionable to the buyer. It is still extensively practiced on the plus 1-in. sizes and particularly on the plus 4-in. and larger sizes. The percentage of ash reduction that can be obtained by hand picking depends entirely upon the amount of free impurity occurring in the coal. In a particularly dirty seam, where a considerable quantity of rock occurs with the coal as mined, hand picking produces sizable reductions in ash. If the coal is prepared clean at the working face hand picking is a final check; in some cases, on the smaller sizes, it is practiced only to show that an effort is being made to prepare a clean product. Because of the variety and different methods of handling coal, the early plants were not always adapted for e5cient hand picking. At most mines an attempt is made to - remove the visual impurities at one or more of the following places in the surface plant: (1) in the tipple during screening; (2) on picking band, belt, or shaking conveyors; (3) during the loading of the coal as it goes into the railroad car. Whatever the physical arrangements of the plant may be, the usual practice is to run the coal over the screen, picking table or boom at such a rate that each piece of impurity is exposed to the view of the picker. Coal should be uniformly sized and spread out on the table so as not to exceed one particle in depth. The flow should be even in tonnage and the speed of travel should be from 30 to 60 ft. per minute and not exceed 80 ft. per minute. The dirtier the coal, the slower the speed required for a fixed number of pickers. Actually, picking capacity depends on the number of particles per minute that can be picked out and rejected. The percentage of impurity removed is determined by this and the average weight of piece rejected. Handling a mixture of sizes from nut to the largest lump over the same picking table or conveyor is not conducive to efficient separation by hand picking because the lump hides the smaller impurities. Picking tables should not exceed 5 ft. in width, so that a picker on either side will be able to remove impurities from the center of the table. Guards usually are placed at the side of the screen, boom or table, to allow the pickers to stand close enough to remove the impurities without too long a reach.

Jan 1, 1950

By W. C. Holliman

This report describes apparatus and procedure used for determining the vapor pressure of aviation gasoline in surveys of commercial aviation-gasoline characteristics made by the Bureau of Mines in cooperation with the Coordinating Fuel and Equipment Committee of the Coordinating Research Council, Inc. (CFR-CRC). The method is a modification of the Reid method, in which a mercury manor is substituted for the Bourdon-type gage of the Reid method. The method was used in earlier surveys made by the National Bureau of Standards in cooperation with the CFR-CRC, and was used in the Bureau of Mines surveys at the request of the cooperating organizations. It is designed for special research problems? particularly in vapor-lock studies, which require a precision greater than obtainable by the Reid vapor pressure method. A repeatability of + 0.01 p.s.i. average deviation from the mean may be obtained by method.

Jan 1, 1950

Approximately half of all the fuel energy used in the United states is now pro-vided by oil and natural gas. A persistent and rapid growth in energy demand during the last 3 decades has been absorbed largely by the liquid and gaseous rather than solid fuels. In 1948 the energy provided by coal was substantially the same as in 1920. Meanwhile, the use of oil and natural gas each had increased fivefold. On a per capita basis, the change is more significant. Coal consumption has dropped from about 6 tons per person to 4-1/2 tons, while oil has increased from 4-1/3 barrels to 14-1/3, and natural gas from 7,500 cubic feet to about 35,000. These facts would have only academic interest if the United States had unlimited supplies of all fuels. However, while the Nation's reserves of coal are adequate to meet our needs for centuries, those of oil and natural gas appear limited. It is obvious, therefore, that the security of our liquid-fuel position would be greatly enhanced if the supply could be based in an increasing degree on solid fuels, such as coal and oil shale, which make up more than 95 percent of our fuel reserves, instead of natural oil and gas. In addition, this would create new employment and help to stabilize the market for coal, which may be facing comparatively bleak prospects in the near future unless its position with respect to other fuels is improved.

Jan 1, 1950

By J. C. Fisher

Martensite transformations in steels and other alloys are characterized in part by the absence of composition changes during the growth of a new phase. Transformation occurs rapidly, and there is insufficient time for long range diffusion or partition of alloying elements to take place; martensite reactions in alloys thus are similar to phase transformations in single component systems. A fundamental understanding of martensite transformations in steels is impossible without knowledge of the free energy change upon transforming austenite (face centered cubic iron containing alloying elements) to ferrite (body centered cubic iron containing alloying elements) of the same chemical composition. The present paper assembles the best information available concerning the influence of temperature and composition on this free energy change. Most of the material has been taken from the work of Johansson,' Mehl and Wells,2 Zener3,4 and Smith;5 and indirectly, through these authors, from the work of Austin.6 In agreement with the generally accepted viewpoint, martensite is assumed to be an ordered solution of carbon in ferrite of the same composition as the parent austenite; only at high temperatures and low carbon concentrations is the carbon in ferrite distributed at random. The properties of the disordered solution are estimated by extrapolating the known properties of iron-carbon solid solutions into the range of supersaturation, and the free energy change associated with ordering is estimated from the theory developed by Zener. By incorporating Smith's recent thermodynamic measurements and Zener's theory of ordering, the present analysis modifies previous estimates of the free energy change associ- ated with martensite transformations. Consider a two component system consisting of a solvent A and a solute B. Let Na and Nb represent mol fractions of A and B respectively, let aa = raNa and ab = YbNb represent activities, and let superscripts 1 and 2 refer to phases 1 and 2. The partial molal free energies of A and B in phases 1 and 2 can be summarized as follows: free energy standard state Fa' - Fao1 = RT In an1 pure A' Fa2 - Fa2 = RT In aa2 pure A2 Fb1 - Fbo = RT In ab1 pure B Fs2 - FB2 = RT In aB2 pure B. The free energy of a gram atom of phase 1 is* AF1 = Na'Fa1 + Nb'Fb1 and that of phase 2 is AF2 = NA2FA2 + NB2Fb2. A martensite transformation from phase 1 to phase 2 requires Na1 = Na2 = Na and NB1 = NB2 = Nb, and the free energy change per gram atom accompanying transformation is AFi-2 = NA(Fa2 - Fa1) + Nb(Fb2 - Fb1) = NA[RT In (aA2/aA1) + AFa1?2] + Nb RT In (aB2/aB1) = Na[RT In (ra2/ra1) + AFa1?2] + Nb RT In (TaVTB1). [1] where yn2, yn1, yB2, yB1 are activity coefficients, and where Ma'+* is the free energy change upon transforming a gram atom of pure A from phase 1 to phase 2 at the temperature in question. For martensite transformations in plain carbon steels, A = iron (Fe), B = carbon (C), 1 = austenite (7). 2 = ferrite (a), and Eq 1 is AFr ?a= NFe[RT In (rf.a/rfer) + AFF.r?a] + TVc RT In (eca/rc1)- L2] Nothing is known concerning the values of yFea and yca for carbon concen- , trations in excess of 0.025 pct. However, the approximation rf.7 = 7f." = 1 cannot be appreciably in error for small carbon concentrations, and Eq 2 reduces to Afr-a = NfeFfer?a1 + NC RT In (rca/rcr)- [3] Johanssonl and Zenera have calculated MFfr?a from the specific heat measurements compiled by Austin.6* Their calculated values agree closely, and are summarized in Table 1. The activity coefficients relative to graphite for carbon dissolved in iron vary with temperature according to the relationships d In rcr/d(1/T) = AHcr-R dlnyca/d(l/T) = AHCa/R where AHc? and AHca are the heats of solution of graphite in y and a iron. Assuming the values of AH to be independent of carbon concentration and temperature, In rCr = AHcr/RT + I1 In rca = AHCa/RT + 12

Jan 1, 1950

By R. Maddin, W. R. Hibbard

A series of X ray experiments conducted by G. I. Taylor' in 1927 and later substantiated in 1939 by J. A. Collins2 both on axially strained aluminum single crystals, revealed evidence that during single slip crystallite rotation occurs in such a manner that " all parts of the material rotated about the transverse direction in the plane of slip."l The actual method of preparing the specimens for X ray examination is not discussed in detail by Taylor except to say that "this specimen was cut parallel to the plane of slip, as calculated from measurements of marks in the surface of the specimen. It was ground and etched till the effect of the new cuts had disappeared. This was verified by applying the same treatment to an un-distorted specimen. The X ray reflectionsl in this case were perfect ones."' Collins, on the other hand, cut his crystals in a mechanical shaper. These surfaces were polished on No. 1, No. 1/0, No. 2/0 and No. 3/0 papers and on a broadcloth lap using No. 600 alundum as a polishing medium. "Finally, the surface was deeply etched in Tucker's reagent. An unde-formed crystal was prepared in the manner described and X rayed to determine whether or not the machining and polishing operations had produced any strain or distortion in the crystal. The Laue spots all seem to be sharp, free from tails and streaks indicating no detectable strains had been introduced in the crystals." Taylor's X ray technique involved the use of "homogeneous X rays from an iron anti-cathode"; whereas Collins used Ka radiation of copper at 31kv and 20 milliamperes. Glancing angle X ray photograms were taken (1) with the axis of rotation of the spectrometer table in the plane of slip and at right angles to the slip direction, and (2) with the axis of the spectrometer table lying along the slip direction. However, eight minute exposures were used in each case and the angle setting of the spectrometer table was increased by one degree for each exposure. With the discovery of the action of three slip systems3 in the plastic deformation of single crystalline alpha brass where, formerly, only one had

Jan 1, 1950

By P. R. Sperry, P. A. Beck, J. Towers

Dahl and Pawlek1 found that electrolytic copper develops extremely coarse grains at 1000°C after about 90 pct reduction by rolling. This coarsening occurs only under conditions of penultimate grain size, deformation, and alloying which lead to the "cube" recrystallization texture.l,2,3,5 The peculiar angular shapes and straight grain boundaries of the coarse grains were noted by several investigator.1,4,5 On the other hand, coarsening in Fe-containing aluminum or in AI-Mn alloys8 does not depend on a "cube" (or any well developed) recrystallization texture. It is true that increasing deformation by rolling, and, therefore, an increasingly well developed re-crystallization texture, are associated with decreasing incubation periods of coarsening.6-7-8 Nevertheless, coarsening readily develops in aluminum even after only 30 pct reduction by rolling, where the recrystallization texture is very weak.6,8 Also, coarsening was observed by Jeffries9 many years ago in sintered thoriated tungsten, which presumably has no preferred orientation. In all these cases coarsening is associated with grain growth inhibition by a dispersed second phase.8,9 The annealing temperature has to be suficiently high to overcome the inhibition at a few locations. But if it is too high, growth starts at many points, and the resulting grain size becomes much smaller.9 Normally, the coarse grains are more or less equiaxed, and the boundaries have a typical ragged appearance.6.8 Cook and Macquarie4 demonstrated that, in addition to the texture-dependent coarsening previously found at 1000°C,l electrolytic tough pitch copper may also coarsen at 800°C after 50 pct reduction by cross rolling. The coarse grains formed under such conditions have rounded shapes and ragged boundaries, like those in aluminum. When the annealing temperature is higher, the tendency for their formation decreases. All these observations suggest that the coarsening at 800°C is associated with inhibition by a second phase. Actually, coarsening at 800°C after 50 pct reduction by cross rolling was observed only in tough pitch copper,4 which contains Cu2O particles. On the other hand, the texture-dependent 1000°C coarsening occurs in both tough pitch and oxygen-free copper;4 it does not appear to depend on the presence of a dispersed second phase. However, the interpretation of the 800°C coarsening in Cu after 50 pct rolling as an inhibition-dependent process, similar to the coarsening in A1-Mn alloys, is somewhat weakened by the fact that this coarsening was reported4 to occur only after cross rolling, and not after straight rolling. It was, therefore, decided to re-examine this question. A 1 in. diam electrolytic tough pitch copper rod, No. 2 hard drawn, was annealed for 20 min at 700°C, rolled to 0.5 in., annealed 10 min at 700°C, and straight rolled to 0.064 in. It was then given a penultimate anneal of 20 min at 500°C and it was cut into four sections, which were given final reductions by straight rolling as follows: A 30 pct reduction of area B 50 pct reduction of area C 70 pct reduction of area D 90 pct reduction of area Specimens cut from the four sections were finally annealed at 800°C in an oxidizing atmosphere. Strip A remained fine grained up to 10 hr, but the specimen annealed 12 hr consisted of only 2 large grains. Strip B had a few scattered large (1/2 to 3/4 mm) grains after 1 min, although the balance of the specimen consisted of fine grains of about 0.02 mm. After 5 min there were several 10 to 15 mm grains present, and after 1 hr strip B was completely coarsened. The coarse grains had the same characteristics (see Fig 1) as those obtained by Cook and Macquarie at 800°C after cross rolling. Strip C had several grains of 0.05 to 1 mm after 1 min, but it was still largely fine grained after 12 hr. After 48 hr it consisted entirely of grains of about 0.5 to 4 mm, with an extraordinarily large number of twin bands. Strip D remained com- pletely fine grained after 4 hr at 800°C. These results indicate that, in the deformation range of 30 to 70 pct reduction, the incubation period for coarsening as well as the rate of growth and the final size of the coarse grains decreases with increasing deformation. Similar

Jan 1, 1950

By Bernard Lewis

This report summarizes the fundamental research and technical studies conducted by the Explosives Branch of the Bureau of Mines from July 1, 1943, to June 30, 1949. It is the thirteenth of a series of annual reports, which have aimed to bring to the reader a resume of the research results that have appeared in published form during each fiscal year. The work of the Explosives Branch covers a number of activities - explosives research, explosives testing, flame and combustion research, flammability of gases and vapors, dust-explosions research, and technical studies in the experimental mine. An important part of the work of the branch is fundamental research to advance our knowledge and understanding of explosion processes. Considerable emphasis has been placed on studies of ignition and flame stabilization, as it is felt that an understanding of these processes should assist materially in alleviating explosion hazards in coal mines. The results are also finding important application in the development of jet propulsion. Studies of the explosibility of gases, vapors, and dusts saving thousands of lives and are preventing the destruction of much property. In innumerable instances in which potential explosion hazards exist, safe operating procedures have been recommended from data taken in the Laboratory. Aware of the value to national security of research results of combustion, flame, and explosion, the Army, Navy, and Air Forces are actively supporting important phases of this fundamental research.

Jan 1, 1950

By J. B. Zadra

Much has been published by various investigators on the use of activated carbon for adsorbing precious metals from cyanide solution and pulp. For the benefit of the reader, a list of these earlier publications appears at the end of this report. The present paper deals only with a process for extracting gold from gold-laden carbon and re-use of the de-adsorbed carbon. At the Getchell mine, Redhouse, Nev., experiments have been in progress for several years concerning the use of activated carbon to adsorb gold from their slime circuit pulp. The experimental work has been successful. Their practice has been to ship the gold-laden carbon to a smelter for treatment, which meant the total loss of the carbon in addition to smelter and freight, charges, all of which proved costly and wasteful.

Jan 1, 1950

By Lowell B. Moon

Concern over possible wartime shortages finally resulted in passage of the Strategic Materials Act in 1939. As authorized by one section of this legislation, the Bureau of Mines proceeded to investigate deposits of seven strategic minerals with the objective of developing tonnages of low-grade material that could be mined in an emergency. During the war, the size of the program and the number of strategic minerals were increased, and the objective was the more immediate one of aiding production. Since the war, the size of the program has been reduced, but the number of minerals on the strategic list continues to be large. The objective has returned to that of 1939. In the course of the program, more than 10,000 examinations were made and about 1,300 projects were run on deposits of 33 different commodities. A considerable contribution to war production was made in six of the commodities investigated, and a minor contribution was made in twelve others. Substantial reserves have been indicated in 19 minerals. Private interest is currently active in some of the deposits developed in 14 commodities.

Jan 1, 1950

By L. C. Armstrong

Twice in the past two years and in two widely separated localities—ane near Williamsville, Mo., and the other in the Allard Lake district of Quebec— the Contract Drilling Division of the Longyear Company has experienced perplexing difficulties in drilling granitoid igneous rocks. The rocks in both places are characterized by appreciable amounts of feldspar intimately inter-grown with quartz particles of microscopic dimensions. The disappointingly slow rate of advance and the exceptionally high bortz loss, obtaining during the life of these two projects, are ascribed largely to the resistance to abrasion of these two minerals when arranged in this intergrown pattern. Whether all intergrowth-bearing igneous rocks would offer extraordinary resistance to bit progress cannot be stated with assurance on the strength of these experiences alone. More data on diamond drilling this sort of material in a number of localities are needed before any generalizations can be made safely. It should be pointed out that the lack of time and funds made it impossible for the writer, or other persons interested in correlating the details of bit histories with the kinds of rocks drilled, to be present during the performance of the contracts. However, the records kept in the normal course of drilling are deemed complete enough to be reportworthy. This information is presented here together with the findings made in studies of the rocks involved, with the thought that it may attract the comments of others who may have encountered similar refractory drilling conditions. A pooling of knowledge on the problem would be of material aid in devising more efficient cutting tools and procedures for penetrating this kind of rock. Drilling Blastholes in the Williamsville Granite Due to the unsatisfactory perform- ance of pneumatic percussion drills in boring blastholes on a construction contract near Williamsville, Mo., tests were made with a diamond drill. The poor progress achieved and the excessive loss of diamonds, however, soon led to the abandonment of these trials. The diamonds, in all of the bits tried, lost their cutting edges and acquired a polish after being in service for distances ranging from a few inches to a few feet. Coring bits containing surface-set, whole-stone bortz in a tungsten powder matrix were employed. The cost assignable to bortz wear averaged $7.17 per foot. This item of expense is several times the amount normally expended in diamond drilling in firm, unfractured, granitic rocks. Diamond-impregnated, tungsten carbide bits also were used without success. The diamond wear was at the rate of $0.98 per foot, but the diamond chips became too polished for further duty in less than a foot of drilling. The Williamsville granite is pink and medium-grained. In the hand specimen, it has a fresh, sound appearance; it is seemingly composed almost entirely of interlocking grains of feldspar and quartz and has no discernible features suggesting a greater durability than is usually found in rocks with this composition and texture. Microscopic examination, however, reveals a predominance of feldspar grains with more or less regularly distributed and sharply angular masses of quartz (see Fig 1). The pattern assumed by the two minerals in this mode of occurrence is referred to as a "graphic intergrowth," as it bears some resemblance to the cuneiform characters of ancient Persian writing. The other principal constituents are quartz-free feldspars (microcline and orthoclase) and quartz. All of these constituents are in nearly equidimensional grains, ranging up to about 3 mm in length. There are also

Jan 1, 1950

By A. D. Schwope, L. R. Jackson, K. F. Smith

Burghoff and Blank1 have pointed out that the creep properties of hard-drawn coppers are closely associated with their individual softening characteristics and have further shown that the creep resistance of various types of copper is improved, under certain circumstances, by cold stretching. In the design of certain types of electrical machinery, it is important to have the creep resistance as high as possible; furthermore, short-time creep strength is important since in many cases stresses are large only during warming-up and cooling-down periods. In this paper, data are presented showing the effect of cold work on the short time creep strengths of various types of commercial copper under several conditions. It is shown that trends from short-time creep tests are evident at longer times. Materials Used in the Investigation The coppers used in this investigation were commercial grade and of two basic types, oxygen free high conductivity (OFHC) and tough pitch. Additions of silver in amounts of 15 and 25 oz per ton were added to each of the two coppers. The analyses of these six coppers are given in Table 1. Originally, they started as wire bars 4 X 4 X 54 in. A. square rod was made by hot rolling the wire bars to 9/16-in. rod in 8 passes. This rod was then cold drawn to 0.445-in.-diam rod and annealed for 3 1/2 hr at 1000°F. It was then cold drawn to 0.325-in. rod and again annealed at 1000°F for 3 1/2 hr. Hard square rods were then made by cold rolling to 0.257 X 0.257-in. rod. Soft wire was made from the hard- drawn material by annealing at 650°F for 3 hr. The final rolling was performed using a set of 9-in. grooved rolls revolving at 30 rpm, which produced square wires. Reductions of approximately 5, 20, 30, and 40 pct were obtained using several passes in the same direction for the large reductions. The 5 pct reduction by drawing was accomplished using a steel die having 2 parallel bearing surfaces. The die angle was 7 1/2 degrees and the wires were lubricated with a paste of ceresin wax dissolved in carbon tetrachloride. The speed of drawing was 13 fpm. Since work was done on only two sides of the wire simultaneously, it was necessary to rotate it 90 degrees each pass to insure uniform deformation. The room-temperature tensile properties of the various tempers are given in Table 2. The grain size of the an- nealed 0.257-in. wires was uniform and averaged about 0.035-0.045 mm. Experimental Procedures for Short-time Creep Tests Standard creep-test frames (Fig 1) were used for the testing. Special fixtures were designed to apply axial compressive and tensile loads to the copper wires. The compression specimens were 1 in. long and the ends were ground flat and parallel. The creep in compression was indicated by the movement of reference marks s-ratched on intersliding platinum strips attached to the moving heads of the fixture. The movement was measured with an optical micrometer fitted with a filar eyepiece on which the smallest division was 0.00005 in. The tensile creep specirriens were 4 in. long which provided ample gripping surface for the jaw-type grips. The platinum strips were attached to a one-inch gauge length of the wire and the creep measured as previously described. The single-specimen furnaces were connected to individual power and control sources. The controlling equipment consisted of Foxboro controllers

Jan 1, 1950

By D. J. McAdam

In a series of papers the author and associates have discussed the influence of temperature on the tensile properties of metals.11-18 These papers present much information about the influence of temperature and the stress system on the conventional indices of mechanical properties, with special attention to the fracture stress. A recent study of the data, however, has revealed much additional information about the influence of temperature on the fundamental factors involved in the flow of metals. The present paper presents results of this study. Attention will be confined almost entirely to results derived from tension tests of unnotched cylindrical specimens at strain rates a little slower than those used in ordinary tension tests. According to a concept first presented by Ludwik and elaborated in recent papers by others,8,9,22,23 the mechanical state of a metal depends on the total plastic strain, but not on the temperature during straining, provided that the only structural changes are those essential to plastic deformation. In the summer of 1948, however, the author made the previously mentioned study of results of a general investigation by the author and associates and reached the conclusion that the mechanical state depends not only on the total strain, but also on the temperature during the straining. A number of diagrams were then prepared. These conclusions were presented without diagrams in a discussion last October of a paper by Dorn, Goldberg and Tietz.2 The metals used in the investigation on which this paper is based were Monel and oxygen-free copper. The Monel was supplied by the International Nickel Co. through the courtesy of Dr. W. A. Mudge. The copper was supplied by the Scomet Engineering Co. through the courtesy of Dr. Sidney Rolle. The data to be presented are based on results of tests at temperatures ranging between 165 and — 188°C. Description of the apparatus and methods of test are given in previous papers.1011'1"2 The present paper is the first part of the general discussion of the influence to temperature on the stress-strain-energy relationship for metals. The next paper will deal with metals that are subject to structural changes other than those induced solely by plastic deformation. Influence of Temperature and Plastic Strain on the Flow Stress of Monel and Copper For a study of the influence of temperature on the stress-strain relationship, flow-stress curves obtained with annealed metals at various temperatures will be compared with curves obtained with the same metals after cold drawing or cold rolling at room temperature. Diagrams thus obtained with Monel and copper are shown in Fig 1 to 8. Fig 1 to 7 show the variation of the flow stress with temperature and plastic strain; Fig 8 is a diagram of a different type, derived from Fig 4 to 7. In Fig 1 to 7 strain is expressed in terms of A0/A, in which A0, and A represent the initial and current areas of cross-section. Since values of Ao/A are represented on a logarithmic scale, abscissas are proportional to true strains; moreover, the true strains representing prior plastic deformation and those representing subsequent strain during a tension test are directly additive. Fig 1 shows flow-stress curves obtained with annealed Monel. Five of the curves are based on results of tension tests. Between yield and the maximum load, the flow was under longitudinal tensile stress; between the maximum load and fracture, the local contraction induced transverse radial tensile stress. The portions of curves designated F, therefore, represent flow with increasing radial stress ratio, the ratio of the transverse stress S3 to the longitudinal stress Si. Curve Fo is based on the ultimate stresses of specimens taken from bars that had been cold drawn various amounts.17 Since the tensile stress at the maximum load is unidirectional, curve Fo represents the course that a flow-stress curve would take if the stress during an entire tension test could be kept unidirectional. The flow-stress curve F obtained at room temperature (Fig 1) has been established accurately by numerous measurements of the diameter of the specimen during the extension from yield to fracture.17 At the time of the experiments, however, no apparatus was available for measuring the diameter during tension tests at low temperatures. Nevertheless, curves have been established to represent with sufficient accuracy the flow at low temperatures. Each flow-stress curve must be tangent to a curve U, which starts at a point representing the ultimate stress of annealed metal. Since the ultimate stress is based on the area of

Jan 1, 1950

By N. A. Gokcen, M. N. Dastur

In metallurgical process industries a knowledge of true melting and casting temperatures is very essential for increasing the operating efficiency as well as improving the quality of the finished product. Optical pyrometers are widely used for the purpose because of their cheapness and ease of operation. It is an unfortunate fact, however, that this mode of measuring temperature entails a source of severe error inasmuch as with all non-black bodies, the temperature observed is always below the true temperature owing to deficient emissive power. Hence, the need for emissivity correction arises. In 1913 Bidwell1 obtained emissivity values of 0.36-0.48 for a temperature range of 1520-1800°C. He measured the true temperature of molten iron by sighting into a carbon cavity immersed in the iron under an atmosphere of hydrogen. In 1914 Burgess2 determined the emissivity of a smooth surface of liquid iron free from oxide to be 0.37 under an atmosphere of hydrogen. He claimed to have attained an accuracy of within 5°C at 1500°C with an optical pyrometer using monochromatic light. He reported that no difference appeared to exist between the emissivities of pure iron and of steels containing considerable percentages of carbon, nickel or manganese; nor was there any appreciable variation of emissivity with temperature from 1530 to 1571°C. Wensel and Roeser3 found an elnissivity value of 0.4 for temperatures above 1375°C for cast iron. The average emissivity value for carbon steels reported by Leiber,4 odd,5 Hase6 and Umino7 range from 0.4 to 0.45. Knowles and Sarjant8 made an extensive study of emissivity of molten iron and steel over a wide range of workshop and laboratory conditions. Observations of true temperature were made with immersion thermocouples, and correlated with apparent temperatures indicated by optical pyrorneter readings taken on the pouring stream as it passed over the lip of the crucible. The emissivity of Armco iron was shown to be of the order of 0.4, rising slightly with increasing temperature. But for plain carbon steels containing up to 1.0 pct carbon the emissivity was shown to fall slightly with increasing temperatures. The results of their investigation are in agreement with those of Guthmann.9 Naeser,10 Spencer," Todd5 and Hase6 in regard to the relation between emissivity and temperature for plain carbon steels. However, Goller12 has found a rise of emissivity with increasing temperature for the same steels. Results of several investigations are given in Fig 1. Measurement of True and Apparent Temperatures The necessity for an accurate optical temperature scale for liquid iron in studies of gas-metal equilibria led to this investigation. Experimental measurements were carried out in the induction furnace used by Dastur and Chipman13 in their studies of the reaction of hydrogen with oxygen in liquid iron. The furnace as modified for this work is shown in Fig 2. The atmosphere of the furnace was a mixture of purified argon with hydrogen containing a small controlled amount of water vapor. Gases were preheated by means of a platinum-10 pct rhodium resistance coil. The stream of hydrogen sweeping across the surface of niolten iron vir-

Jan 1, 1950

By K. K. Kelley

The first bulletin (269) 3 in this series, which appeared in 1932, compiled the entropy values then available for the elements and in-organic compounds, results being listed for some 150 substances. Elaborations and revisions followed in 1936 (272) and 1941 (280), when over 500 usable entropy values were tabulated. The present bulletin constitutes a further elaboration and revision. The accumulation of data since 1940 has been marked, and 800 entropy values now are available. The present bulletin also contains all the pertinent explanatory matter that appeared in its predecessors. Thus, it retains the same dual purpose of assembling the available values of the entropies at 298.16° K. of the elements and inorganic compounds and giving enough explanation of methods of calculating entropies to make the results comprehensible.

Jan 1, 1950

By W. A. Selvig

EQUIREMENTS of montan wax for industrial use in the United States before World War II were met by imports, nearly all of which came from Germany. An important industry for extraction and refinement of this wax from certain brown coals had developed in Germany. At the beginning of the war, montan-wax imports were shut oft, and American industry was forced to rely largely on substitutes. Since the war, relatively small amounts have been imported from Czechoslovakia. Because of the shortage of montan wax at the close of the war and the fact that industry in the United States had to rely on foreign sources in the past, this investigation was started in 1945 to determine probable yields of wax from domestic lignite. Results of the investigation and the properties of extracted waxes are described in this report. Also included in the report are discussions of the occurrence and geology of lignite deposits of the United States from which samples were obtained for wax extraction and the petrographic composition of lignites, particularly in respect to those components that contribute to wax yields.

Jan 1, 1950

By D. Harrington

The primary objective of this paper is to discuss the hazards and furnish a list of recommendations for the safe operation of quarries and related works. They have been compiled from Bureau of Mines publications covering the safety experience of engineers before and during the year in the mineral industry,5 from a publication of the National Safety Council, Inc.,6 from explosives recommendations made by various explosives manufacturers,7 and from suggestions obtained from quarries visited. The second objective is to describe and illustrate safety devices, practices, and quarrying methods. The quarrying and related industries of the United States had a lower accident-frequency rate than either the metal- or coal-mining industry as reported for 1942.8 However, the quarry industry ranked eleventh in 15 major industries during 1942 in lost-time accident fre¬quency; metal mining ranked fourteenth and coal mining fifteenth.

Jan 1, 1950

By Kenneth H. Johnston

The Weber pool in Washington County, Okla. (fig. 1), covers an area extending from 2 miles east and slightly north of Bartlesville, Okla., to a point approximately 2-1P tiles northeast of Dewey, Okla. The pool is a part of the area designated by the Standing Committee on Oil Field Nomenclature, Kansas-Oklahoma Division, Mid-Continent Oil & Gas Association, as the Bartlesville-Dewey field. In the following discussion of the geology, development, and exploitation of the Weber pool, the writers, by means of structure maps, cross sections through various parts of the reservoir, and tabulated development data and production statistics, have recorded salient information on a field that was developed before .1910 in an Area that has been repressured since 1926. The total oil production to January 1, 19.0., from the 2,639 developed acres considered in this report, was approximately 14 million barrels, or a recovery of about 5,3;2 barrels per acre, or 227 barrels per acre-foot. The production of the estimated 18 million barrels of recoverable oil remaining in the Bartlesville sand reservoir will require the initiation of additional secondary-recovery practices on some of the leases and the application of a more systematic repressuring program on others.

Jan 1, 1950

INTERNATIONAL conferences on safety in mines originated in 1912 when, in response to an invitation issued by the United States, representatives of Austria-Hungary, Belgium, France, and Germany participated in a conference held in Pittsburgh, Pa The record shows that a permanent organization was proposed to be developed through. diplomatic channels. However, the advent of war 2 years later prevented this proposal from coming to fruition. No further cooperation between the Bureau of Mines and a group having: similar interests in a foreign country took place until 1924, when formal cooperation with the Safety in Mines Research Board of Great Britain was established. Interchange of personnel and results of research under that arrangement have resulted in a number of publications in both countries and more rapid advance in knowledge than could have been obtained through the same efforts exerted independently.

Jan 1, 1950

By Thomas Fraser

WHEN the Bureau of Mines initiated the program of large-scale research and development in the field of synthetic liquid fuels authorized in the Synthetic Liquid Fuels Act of April 5, 1044, the Coal Preparation Section was assigned the task of obtaining data on the preparation characteristics of the coal in large reserves that might be adaptable to use in this new industry. It is natural that, as the rapidly developing general research program brought about new concepts of raw-material quality, preferred geographical location, and the like, the orientation of coal-preparation investigations should have undergone some change. The first major assignment was the sampling and testing of a series of typical American coals deemed to he suitable for hydrogenation based on early research work conducted by the Bureau of Mines. This first series of tests has been completed and is reported in this paper.

Jan 1, 1950