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By M. R. Meyer, W. T. Walter

A great deal is known, in a qualitative sense, about the performance of CMI EB-36 centrifuges. The manufacturer can give reliable guidance for the proper operation of its centrifuges and can give general estimates of expected product moisture and recovery. Quantitative estimates of the effects of changes in the various operating parameters are more difficult to find. The engineer faced with designing a preparation plant may be without the specific data needed to make decisions. For example, to obtain optimum product moisture when drying 9.5 mm X 595 µm (0.4 in. x 28 mesh) coal the centrifuge manufacturer recommends having no more than 5% -595 µm (-28 mesh) material in the centrifuge feed. They know that more -595 µm (-28 mesh)material in the feed will cause higher product moistures, but they usually cannot quantify the increased moisture or describe the shape of the product moisture versus -595 µm (-28 mesh) in the feed curve. This study was conceived to provide quantitative information on the EB-36 centrifuges, focusing on product moisture, recovery, and size degradation. All of the centrifuges tested were Model EB-36 dryers from Centrifugal and Mechanical Industries Inc. (CMI), with feeds in the nominal 9.5 mm x 595 pm (0.4 in. x 28 mesh) range. These are typical centrifugal dryers in this application, and many were available for testing.

Jan 1, 1984

By F. D. Rosi, C. H. Mathews

THE plastic properties of face-centered cubic metals below room temperature present a field of investigation which has not been extensively ex-plored. The work by Schmid and Boas1 has demonstrated the importance of temperature upon such properties as strain hardening and critical resolved shear stress. The work by Yamaguchi2 upon the shear stress as related to the number of slip bands accentuates the necessity for further experiments of a similar nature. The approach to a mechanical equation of state from the standpoint of thermal fluctuations and activation energies by Becker3 and more recently by Kauzmann4 further emphasizes the need for a quantitative and more comprehensive analysis of the dependence of fundamental plastic properties on temperature. The purpose of the present work was to investigate specifically: (1) The gross shape of the stress-strain curves at several temperatures, (2) the change in the critical shear stress as a function of temperature, and (3) the number and appearance of slip bands as a function of strain and temperature. Preparation of Specimens Single-crystal specimens of 99.996+ pct alumi-num, 1/2 in. in diam and 5 to 6 in. in length, were made by the Bridgman method of gradual solidification from the liquid state. The crystallographic orientation of the single crystals was determined from back-reflection, Laue X-ray photograms ac-cording to the method described by Greninger.6 In most specimens the Laue photograms showed double diffraction spots indicative of the lineage structure type of imperfection, discussed in great detail by Buerger.7 The angular spread of these spots was never observed to exceed 2". Most of the crystals were radiographed to insure against microporosity. In preparing the metal surface for optical microscopy, the following sequence of operations gave good results: The as-cast crystals were turned down in a lathe, 0.001 in. per cut, to obtain a 2.5 in. gauge length. The cold-worked layer resulting from this operation was removed chemically by etching with Tucker's reagent. Then the specimen was polished mechanically through 2/0 metallographic emery paper, after which it was etched again to remove the cold-worked layer resulting from the mechanical treatment. A 48-hr anneal at 580°C ±10°C followed so as to insure an essentially stress-free single crystal. After the annealing treatment, the specimen was electrolytically polished in a 2:l solution of methyl alcohol and concentrated nitric acid. With a current density of 10 amp per sq dm (decimeter) the time required to obtain a satisfactory surface varied from 10 to 12 min. The polish-ing was carried out for short periods of 2 min to avoid rapid deterioration of the solution as well as to enable the rotation of the specimen 180" for uniformity of polish. It was necessary to place the solution in a bath of dry ice in view of its explosive nature at room temperature. Etching of the electrolytically polished surface was accomplished by using the fuming etch-pit method recommended by Lacombe and Beaujard8 for high-purity aluminum. Method for Tensile Testing A modification of the loading equipment devised by Miller9 was used. In this apparatus, the specimen was suspended from a chain and gimbal arrangement (for axial loading) in a heavy steel framework connected at the bottom to a balanced 6:1 lever and bucket system. Loading of the specimen was accomplished by allowing sand to flow from a reservoir into the bucket suspended from the longer end of the lever-arm at a rate of approximately 3 lb per min. Strain measurements were made using the Baldwin SR-4, bonded, resistance-wire, strain gauge and an SR-4 portable strain indicator (type K), which permits a reading accuracy of 2 microinches per inch. For low-temperature study, the gauge was calibrated by measuring the elastic modulus of an annealed stainless steel rod, which is known to be independent of temperature."

Jan 1, 1951

By J. S. Pascover, S. V. Radcliffe

The structures and transformation temperatures of high-purity Fe-Cr alloys have been investigated as functions of composition (0 to 10 wt pct Cr) and rate of quenching from the high-temperature Y phase field (up to 40,000°C sec-1). The structures were chmacterized by transmission electron microscopy. The transformation temperatures for each alloy exhibited the progressive decrease to a constant value with increasing cooling rate which has been shown to be characteristic of several iron binary systems. The corresponding structures were found to become increasingly finer in scale with increasing cooling rate and solute content, but to remain essentially equiaxed in character. In all the materials except the high-purity iron and one of the alloys, an additional and lower transformation temperature than the constant value for the equiaxed structures was observed. The structures of specimens which transformed at these lower temperatures (only single thermal wrests were observed in any given run) were martensitic and consisted of arrays of fine ferrite laths which varied in size and morphology with changing solute content. The factors controlling the nature of these transformations are discussed. The composition dependence of the martensitic transformation temperature, ME, in Fe-Cr alloys together with those reported for other iron binary systems indicate that MB for pure iron is some 700°c, rather than the values of 550° and 760°C reported previously. This conclusion is further supported by the results of a compmison of the thermodynamics of mmtensite formation in several systems. ThE extensive investigations of the structures formed on athermal transformation in iron and its alloys have led to the characterization of several forms of martensitic or "military"1,2 transformations and, in addition, a "civilian7' transformation to ferrite or "equiaxed a"* which occurs athermally and at a very high rate.374

Jan 1, 1969

By Jack Parker

There are some simple theoretical approaches to pillar design but they leave much to be desired. There are also more complex theoretical approaches, but at this time the most realistic approach is to go into the mines and observe and measure how real pillars are performing under real conditions; to allow the information thus gathered to ferment in our minds - then to project the behaviour of those pillars into our new designs and mining techniques, probably with no formulas at all. Examples, from half-a-dozen different mines, show how a simple- minded approach, through observation and measurement, led to changes in pillar design which often contradicted the textbook but made very significant contributions to mining safety, efficiency and costs. The good news is that we know a lot more about pillar design than we realize. We have, between us, looked at millions of pillars of all kinds, under all conditions, but we have overlooked what they are trying to tell us. We can take problem situations and turn them into opportunities and, in that way, become better stewards of the resources which have been given to us.

Jan 1, 1983

By Hallan N. Marsh

The subject of mud sounds so simple, uninteresting and unimportant that it has failed to receive the attention that it deserves, at least as applied to the drilling of oil wells. As a matter of fact, it is one of the most complicated, technical, important and interesting subjects in connection with rotary drilling. In 1923, R. E. Colloml said "It should be possible to establish certain physical standards for mud fluid," but while considerable work has probably been done on the subject before and since that time, and numerous articles have been written, the progress of general knowledge of the subject and the application of better practices have not kept pace with other developments in rotary drilling, and physical standards cannot be considered as established. Mud is apt to be thought of as an accessible and cheap material, but its cost is likely to be an important factor in the total cost of drilling a well. Some wells "make" most of their own mud out of the formations drilled, but in most cases a great deal of mud-making material has to be supplied from more or less distant sources. Expenditures for mud materials by one California company totaled practically one-quarter million dollars during 1929 and averaged about $13 per rig per drilling day, or about $2000 per well. Under unfavorable conditions, mud cost may reach many times this figure. Parker2 says that in the Hobbs, N. M., field "as much as $75,000 has been spent on one well alone for mud and mud-weighting compounds."' Presumably this is an exceptional case. Unit cost of mud fluid will range from 10 c. per barrel, where suitable material is close at hand, to $1 where crude material is available at moderate price but must be hauled long distances, and on up to as much as $11 per barrel where high gas pressure requires the use of special processed weighting material. The cost of mud pales into insignificance, however, when the results of using improper mud are considered. Blow-outs and lost circulation are obviously the result of inadequate mud. Stuck drill pipe, whether or not twisted off, in many if not most cases probably is caused by cuttings settling out of the mud or the mud itself precipitating. Recent experi-

Jan 1, 1931

By M. P. Tixier, K. S. Kunz

A method for the interpretation of temperature curves recorded in gas producing wells is described. One essen-tial feature of the method is a simple graphical construction which conveniently reflects the amount of gas flowing from a given producing formation. This method, applied in conjunction with the Induction Log and radioactivity logs, is valuable to determine the points of entry of gas and to estimate the over-all thickness of the producing zones and their respective contributions to the total production. The method in particular is helpful in evaluating the effect of fracturing operations. An outstanding result of the application of the method is to bring to the light the relative importance of sand-shale interfaces in the production of gas. The paper is illustrated with field examp1es. INTRODUCTION The electrical logging tools involving conventional systems are not applied in wells which do not contain water base mud (empty holes, or wells filled with oil base mud), because of the absence of electrical connection between the electrodes and the surrounding formations. It is, therefore, common practice in this case to use other methods which do not require the presence of a conductive fluid in the borehole: resistivity log with scratcher electrodes, Induction Log, radioactivity logs, temperature log. . . . Such conditions are encountered in some regions, as the San Juan Basin, N. Mex., where a technique of drilling gas wells, using gas as a drilling fluid, has been introduced in the last two years. By the middle of 1953, an appropriate method for the logging of these wells was devised on the basis of field tests and of theoretical studies. It is the purpose of the present paper to give a description of this method. In these wells the logging operations are performed during the process of gas production, so that the temperatures in the boreholes are strongly affected by the cooling due to the expansion of the gas. On the other hand, a special thermometer, with a high sensivity and a short time constant, has been recently made available, which has enabled much more detailed and accurate recordings of the borehole temperatures than with the conventional instruments. As a result of these two circumstances, the temperature log constitutes the essential element of the method, in making possible the detection of the gas producing zones, the definition of their boundaries, and the estimation of the respective contributions of each separate zone to the total production. The method also involves the radioactivity and Induction Logs, as auxiliary documents. These logs in the present instance are helpful in the determination of the reservoirs. However, the information they give in this respect is limited. This comes from the fact that, due to the absence of the MicroLog and/or MicroLaterolog and of the SP log, the estimation of formation factors and connate water salinities is somewhat conjectural. Furthermore, little help is obtained from the Neutron log for the evaluation of porosity and of formation factor because the variations of gas saturation affect the Neutron log in a way similar to the variations of porosity. It should be said also that even an exact knowledge of the gas saturation of the reservoir beds would not

Jan 1, 1956

By E. DeGolyer

The only known direct method of discovering oil deposits is by the drilling of test wells. Such exploration is always hazardous and generally very costly. The problem of the prospector, therefore, is to select test sites that are favorably located and so to reduce the odds against his venture. Early in the history of the oil industry, it was realized that oil and gas deposits, other conditions being favorable, were usually found in anticlinal types of structure. This very undestandable and rational habit of occurrence furnished the first substantial clue to the prospector. Oil occurs in sedimentary rocks, and beds of such rocks are deposited originally in approximately parallel layers. An anticline at the surface, therefore, could be accepted as an indication of an anticline in lower beds. Structural geology became the tool of the prospector, and by its use in the past two decades the majority of the known important oil deposits of the world have been discovered. This is but a partial, and the simplest, statement of the problem, Nine-tenths and more of the important oil pools of the world belong to the great class of accumulations controlled by structural traps—anti-clines, faulted structures, salt domes, etc.—but by no means all of these structures are clearly or adequately expressed at the surface. As the more obvious anticlines were explored and the search for new deposits led to the testing of progressively deeper beds, it became more and more apparent that marked favorable structures involving petroliferous rocks can, and do, exist without any marked surface expression. There are great areas where the surface, covered by some masking material such as water, alluvium, glacial deposits, or sand dunes, affords no clue to structural conditions in the subsurface, and there are also regions where the surface formations are unconformable with the oil-bearing formations. The structure in which the prospector is fundamentally interested is that of the oil-bearing formation itself, together with roof and floor beds. No other geologic information is of interest or importance to him except as it affords clues to the stratigraphy and structure of the supposed oil-bearing formations.

Jan 1, 1932

By I. J. Demer, M. L. Holzworth, J. C. Kremer, P. A. Beck

For alloys which are in practice heat treated to obtain increased strength, such as steels, duralumin, copper-beryllium, and others, the treatment usually involves heating to a relatively high temperature. At such temperatures the grain size of the product is largely determined by grain growth. Even in metals and alloys annealed merely to relieve work hardening, recrystal-lization is generally followed by a certain amount of grain growth. Thus, effective grain size control, which is often of great practical importance in manufacturing processes, depends on the grain growth behavior of the material used. Despite its importance, grain growth has been the subject of few investigations of a fundamental nature. The term "grain growth" has been used to designate a group of related, but distinctly different, phenomena. The two most important and best known of this group are illustrated by the following example. Curve a in Fig I shows the increase of the average grain size of a copper-beryllium alloy, containing 2 pct Be and 0.15 pct Co, with increasing annealing temperature. The time of annealing was 2 hr. The grain size was quite uniform in all specimens. The results of a similar experiment with an alloy containing 2 pct Be and 0.31 pct Co are shown by curve b It is seen that for any annealing temperature below T, the grain size was smaller than. in the previous case. Grain growth became slower with the higher Co content. This "inhibiting" effect of the higher Co addition was associated with the appearance in the microstructure of fine, light blue particles of the CoBe phase. Up to temperature T, the structure of the inhibited alloy (curve b) was just as uniform as the structures represented by curve a. However, after annealing at T or at higher temperatures, the inhibited alloy showed some extremely large grains (much larger than the grain sizes developed by the uninhibited alloy with low Co content) mixed with the small grains according to curve b. The presence of these mixed or "duplex" structures is indicated in Fig I by the vertical lines branching off curve b. The type of grain growth occurring in uninhibited Cu-Be alloys (curve a) has been most frequently and best investigated in brass. This type has been designated as "normal grain growth,'' while the grain growth phenomena occurring in inhibited materials were, at times, referred to as "abnormal grain growth." However, since the latter term has been applied occasionally to the phenomenon of critical recrystallization, which also results in large grains although by an entirely different mechanism, in the present paper a different nomenclature has been adopted in order to avoid confusion. Typical of the grain growth in uninhibited metals and alloys is the continuous

Jan 1, 1949

By L. B. Herring, Harold Decker

The area under discussion includes districts 2 and 4, so designated by the Texas Railroad Commission,‡ and comprises the following 26 counties: Bee, Brooks, Calhoun, Cameron, De Witt, Duval, Goliad, Gonzales, Hidalgo, Jackson, Jim Hogg, Jim Wells, Karnes, Kenedy, Kleburg, Lavaca, Live Oak, Nueces, Refu-gio, San Patricia, Starr, Victoria, Webb, Willacy, Wilson and Zapata. Drilling and Production The total number of wells drilled in this district during 1944 is shown in Table 5. This indicates a 41 per cent increase in all drilling over 1943. In spite of every handicap created by the war, the oil industry more than met the crisis in its drilling program in this district. Last year we thought it would be impossible to add to the total number of wells drilled in the previous yea;, but in spite of the lack of manpower and materials this large increase was shown. During 1944 this district produced 124,201,978 bbl. of oil from 11,607 producing wells, whereas in 1943 it produced 88,421,693 bbl. from 11,211 producing wells. This is an increase of 35,780,285 bbl. of oil. Some decline has been shown in the older fields arid undoubtedly the majority of wells in the district are producing at too high a rate. However, this district has been able to meet any demands made on it by the Petroleum Administration for War for increased production. Discoveries and Extensions There was a slight decline over the preceding year in the number of wildcats drilled, but the number of discoveries increased. In most instances subsequent development has not been sufficient to arrive at preliminary valuations but it appears that the over-all oil discoveries were below normal and that the gas discovcrics were relatively more important. The Canolis and Tijerina pools, Jim Wells County, and the Dan Sullivan pool, Brooks County, appear to be the outstanding oil discoveries of the year. No important oil reserve was discovered or developed in the Wilcox horizons, although considerable wildcatting was done. Important extensions were made at Agua Dulce and Stratton in Nueces and Teleberg Counties. Production was increased appreciably at Willimar, Willacy County, and Seeligson, Jim Wells County, in sands and areas which were apparently productive at the beginning of the year. Refining Most of the major work in the changing and completing of refineries was finished this past year. Some of the most modern refineries in the industry are now located in the Corpus Christi area. Gas and Condensate No new recycling projects were commenced during the year, nor were there any important additions to the old operations. No major gas reserve was developed, although several new discoveries suggest potentid possibilities.

Jan 1, 1945

By R. A. Kinzie

THE major operating costs in a cement plant are labor, power, and fuel. The opportunities and methods of savings in labor and power parallel other industries. Because our industry's use of fuel is large and its method of use is unique, the devices adapted for saving fuel are of interest. In normal practice the raw material in the form of a dry powder or a mud is fed to a rotating inclined cylinder where it is dried, calcined, and clinkered. In a Lepol kiln the raw material is rolled up into little balls with water in the nodulizer, fed to a traveling grate on which it is dried and partially calcined and tben to a short kiln where the process is finished. The more usual methods of saving heat have been the use of long kilns with chains in wet process plants and the use of waste heat boilers in dry plants (fig. 1). At the Santa Cruz plant we have used a Lepol system kiln and achieved a fuel 'economy of 4.7 gal per bbl of clinker or about 704,-000 Btu per bbl. This can be compared with our old kilns using the same fuel and raw material which consume 7.8 gal per bbl or 1,130,000 Btu per bbl. These are gross Btu and not the net figures usually used in reports of foreign companies. Our average consumption for 1948 was 708,000 Btu per bbl of Lepol clinker, based on cement sold, and oil purchased. The overall fuel consumption for 1948 was 6.61 gal per bbl. The Lepol system consists of a nodulizer, a grate, and a kiln. There is the usual accessory equipment which is similar to that used in other cement plants. The following description covers the equipment in operation at our plant. The nodulizer is a cylinder 8 ft 10 in. in diam by 18 ft long set on a slope of 1/2 in. per ft, and rotated at about 10 rpm. It is driven by a 50 hp wound rotor motor drawing about 9 kw. The inside of the shell is cleaned by a continuously operating scraper which draws 0.1 kw. The dry raw material is fed to the nodulizer where, being sprayed with water, it rolls into small spheres about 90 pct being between 1/2 and 1 in. in diam and containing about 15 pct water. The nodules fall on the traveling grate where the hot gas from the kiln is pulled down through the

Jan 1, 1951

By R. A. Kinzie

THE major operating costs in a cement plant are labor, power, and fuel. The opportunities and methods of savings in labor and power parallel other industries. Because our industry's use of fuel is large and its method of use is unique, the devices adapted for saving fuel are of interest. In normal practice the raw material in the form of a dry powder or a mud is fed to a rotating inclined cylinder where it is dried, calcined, and clinkered. In a Lepol kiln the raw material is rolled up into little balls with water in the nodulizer, fed to a traveling grate on which it is dried and partially calcined and tben to a short kiln where the process is finished. The more usual methods of saving heat have been the use of long kilns with chains in wet process plants and the use of waste heat boilers in dry plants (fig. 1). At the Santa Cruz plant we have used a Lepol system kiln and achieved a fuel 'economy of 4.7 gal per bbl of clinker or about 704,-000 Btu per bbl. This can be compared with our old kilns using the same fuel and raw material which consume 7.8 gal per bbl or 1,130,000 Btu per bbl. These are gross Btu and not the net figures usually used in reports of foreign companies. Our average consumption for 1948 was 708,000 Btu per bbl of Lepol clinker, based on cement sold, and oil purchased. The overall fuel consumption for 1948 was 6.61 gal per bbl. The Lepol system consists of a nodulizer, a grate, and a kiln. There is the usual accessory equipment which is similar to that used in other cement plants. The following description covers the equipment in operation at our plant. The nodulizer is a cylinder 8 ft 10 in. in diam by 18 ft long set on a slope of 1/2 in. per ft, and rotated at about 10 rpm. It is driven by a 50 hp wound rotor motor drawing about 9 kw. The inside of the shell is cleaned by a continuously operating scraper which draws 0.1 kw. The dry raw material is fed to the nodulizer where, being sprayed with water, it rolls into small spheres about 90 pct being between 1/2 and 1 in. in diam and containing about 15 pct water. The nodules fall on the traveling grate where the hot gas from the kiln is pulled down through the

Jan 1, 1951

By R. H. Frazier, J. M. Hodge, F. W. Boulger

This paper reports the results of studies of the impact properties of quenched and tempered alloy-steel plates as a function of sulfur content. It was found that the impact energy levels decreased continuously as the sulfur content increased and that there was a straight-line relationship between impact energy and sulfur content when plotted on logarithmic coordinates. Cross rolling raised the level of these Lines for transverse tests and lowered the level for logitudinal tests proportionately to the amount of cross rolling. ALTHOUGH it has been generally recognized that, for applications in which notch toughness is critical, the sulfur content of the steels used should be held to a low value, quantitative information on the effect of sulfur on notch toughness has not been available. For such applications, it is a common practice to specify minimum impact values, and in order that these may be met consistently it is important that the steel producer know quantitatively the effect of sulfur on notch toughness so that realistic sulfur content limits can be applied to the steels they produce. In many instances, particularly in flat-rolled products, impact properties are specified in the direction transverse to the principal rolling direction, so that the factors affecting the anisotropy or directionality of impact properties are also of concern to the steel producer. For some applications, furthermore, it is a common practice to increase the sulfur content of steels in order to improve their machinability, and, in such instances, the effect of this practice on notch toughness may often be of concern. This paper reports on an investigation, carried out at Battelle Memorial Institute, designed to furnish this quantitative information on the effect of sulfur on notch toughness and also to furnish further information on the factors affecting the anisotropy of impact properties in wrought heat-treated alloy steels. MATERIALS AND EXPERIMENTAL PROCEDURE The experimental steels were of intended base analysis: 0.30 pct C, 0.80 pct Mn, 0.25 pct Si, 2.5 pct Ni, 0.80 pct Cr, and 0.45 pct Mo. Steels were made with sulfur contents varying from 0.005 to 0.179 pct. The steels were prepared from 600-lb induction-furnace melts. Steels containing 0.020 pct or more sulfur (at meltdown) were melted from a charge of ingot iron (except for one heat): lower-sulfur steels were made from electrolytic iron. The charge consisted of ingot or electrolytic iron, ferrosilicon to give 0.10 pct Si, and ferromanganese to give 0.05 pct Mn. At meltdown, electrolytic nickel, ferromolybdenum, iron phosphide, and pyrite were added followed in sequence by ferrochromium, sili-comanganese, ferrosilicon, and ferromanganese. The slag was then removed and graphite added to give the desired carbon content. Bath temperature was adjusted to 2850°F and, when no other additions were to follow, 2 lb per ton of aluminum was added, immediately before tapping. Compositions of the experimental steels appear in Table I. Analyses are from single determinations, except sulfur which was analyzed in duplicate. A test sample (3 in. in diam by 6 in. long) and a 575-1b ingot were poured from each heat. The test sample was poured in a sand mold; the cooling rates of the test sample and the large ingot were approximately the same. Chemical analysis chips and metal lographic specimens were taken from the test samples. The ingot was 8 in. sq at the base and 9 in. sq at the top. A 5 X 5 X 6-in. sand mold hot top was completely filled in teeming the ingot. After solidification, the mold was stripped from the ingot which cooled to room temperature. Ingots were reheated to 2250"F and rolled to 1.9-in. slabs on a commercial mill. The slabs were box-cooled to room temperature. Sections of the 1.9-in. slabs were heated to 2250°F and rolled on a Battelle laboratory mill according to one of three schedules: 1) rolled straightaway to 0.5-in. plate; 2) rolled straightaway to 1.3-in. thickness, then cross rolled to 0.5-in. plate (29 pct cross rolling); or 3) cross rolled from 1.9-in. to 0.5-in.-thick plate (46 pct cross rolling). The 0.5-in.-straight- or cross-rolled plates were normalized at 1700°F for 1 hr and then water quenched from 1600°F. Plates were then tempered 2 hr at 1240°, 1170°, 1080°, or 860°F to obtain Rockwell C hardness of 25, 30, 35, and 40, respectively. Tempering was followed by quenching to room temperature to avoid temper embrittlement. Slack-quenched plates were isothermally transformed for 26 min at 800°F, quenched, and tempered 2 hr at 1170°F. Pearlitic microstructures were obtained by holding 168 hr at 1200° F, followed by quenching. Charpy V-notch specimens were taken both transverse and longitudinal to the main rolling direction, notched perpendicular to the plate surface, and tested. Slabs and plates which were to be homogenized

Jan 1, 1960

By R. C. Nelson, T. L. Weaver, A. I. Michals

This paper describes the design and performance of an apparatus for making continuous nondestructive resistance measurements throughout a spool of fine wire. Highly reproducible results on clean and graphite coated tungsten and rnolybdenum wires from 1 to 9.5 mil are presented. A linear relation between resistance and wire weight (per standard length) was obtained on clean wires, but only on those coated wires with very uniform coatings. Results indicating a correlation between tensile strength, hardness, and resistivity are reported. THE increasing demand for greater uniformity in fine tungsten and molybdenum wires destined for use as mandrels, grids, and coils in radio tubes and as filaments in light bulbs has rendered inadequate the standard (sampling) approach to the control of wire diameter and other physical properties. This ap-

Jan 1, 1961

By Evan Just

THE high standards of living and improved national security that industrialization can bring are so evident that no country can be named that does not cherish the hope of industrializing. With such a universal aim, why do many countries unable to develop their own industries accomplish so little toward attracting the foreign private investor, who alone can provide them with the necessary capital and skill? Obviously, because they fail to under- stand what constitutes a favorable climate for investment, because they have false notions about being exploited or dominated by the foreign investor, or because they are so nationalistic they refuse to permit outside assistance. The purpose of this paper is to aid the citizens and policy makers of developing countries in achieving their aims, by defining the conditions which en- courage investment and portraying the results of a policy of encouragement. The following is quoted from Eugene R. Black, president of the World Bank:

Jan 6, 1957

By R. L. Loofbourow

The objectives of this report are (1) to indicate what is known of natural rock temperatures as deep as 5000 ft below the surface, (2) to indicate methods for estimating such temperatures in localities where directly measured temperatures are un- available, and (3) to outline as far as possible, areas in the 48 states within which rock temperatures are likely to be low and high. The usual object of temperature measurements in deep mines and wells is to learn the temperature of air or another circulating medium. This usually differs significantly from the undisturbed rock temperature. The subject is complicated further by the variety of the thermal properties and structures of rock masses, the migration of fluids within them, the diversity of the history of rock masses and of the processes which have been at work on them during that history.

Jan 1, 1966

By William H. Spice

Exploratory drilling in South Central Texas for the year 1944 showed a marked increase over that of 1943 and resulted in a similar increase in new fields discovered. In this area, which comprises the 30 counties included in district No. I, Oil and Gas Division, Railroad Commission of Texas,? 61 exploratory wells were drilled during 1944 as compared with 29 exploratory wells drilled during 1943, or an increase of over 100 per cent. Three new oil fields, two new gas fields and one gas-distillate field were discovered during the year, as compared with one new oil field and one new gas field discovered during 1943. These new fields were the result of exploratory drilling throughout the district along the Wilcox trend and the deeper Edwards lime trend, which was started during the previous year. The Wilcox trend yielded the new Loma iilta-Wilcox oil field and the San Caja gas-* tlistillate field, both in McMullen County. The Charlotte field, in Atascosa County, was discovered along the deeper Edwards lime trend. These three discoveries were of considerable importance and subsequent development should indicate the desirability of continued exploration along these trends. The other three discoveries, United oil field in Guadalupe County, Pederson gas field in Milam County and Van Cleve gas field in Zavalla County, were of minor importance. Charlotte Field, Atascosa County, was discovered by the Humble Oil and Refining Company's No. 3 Pruitt, completcd on Aug. 9, 1944, flowing 176 bbl. per day, 3/16-in. choke, 710 lb. tubing, 475 lb. casing pressures, 37.7º A.P.I. gravity, from the top of the Edwards lime from 6917 to 6923 ft. Two oil wells were completed during the year in this field. This discovery is 14 miles southwest of the same company's Imogene field, also producing from the Edwards lime but with considerable difference in reservoir characteristics. The discovery of this field is the result of surface geology and subsequent seismograph survey of the area. Loma Alta-Wilcox Field, McMullen County, was discovered by the Atlantic Refining Company's No. I Atkinson, completed on June I, 1944, flowing 102 bbl. per day, 9/64-in. choke, 1900 lb. tubing pressure, 37º A.P.I. gravity, from Wilcox sand from 6866 to 6869 ft. after being drilled to a total depth of 7185 ft. This discovery is the result of subsurface geology and an extensive seismograph survey of the entire area. Sun Caja Field, McMullen County, was discovered by Edwin M. Jones No. 2-C Ezzell, completed on June 2, 1944 as a dual completion in the Wilcox sands, flowing 1,740,000 cu. ft. gas with 53 bbl. distillate, 1/4-in. choke, 2035 lb. tubing pressure, 53.2º A.P.I. gravity, from sand 6416 to 6453 ft. and flowing 2,000,000 cu. ft. of gas with 127 bbl. distillate, 1/4-in. choke, 2500 lb. tubing pressure, 50º A.P.I. gravity, from sand 6889 to 6916 ft., after being drilled to a total depth of 7264 ft. Three gas-distillate wells were completed during

Jan 1, 1945

By H. J. Levinstein, H. J. Guggenheim, C. D. Capio

An optical incestigation of the phase transformations in RbFeF, has been conducted. Details of the ferromagwetic phase transition and the metamagnetic state are disczrssed. The three-dimensional magnetic domain structure existing in bulk crystals of RbFeF3 is described, as well as the effect of the magnitude and direction of the applied magnetic field on the domain struclure. The strong magnetoelastic interaction in RbFeF, is demonstrated. The results of the direct observation of the role of dislocation subboundaries and slip bands as nucleation sites and as pinning sites for magnetic domain walls are reported. THE perovskite compound RbFeF, has recently been shown to exhibit three magnetic states.''' Above 102°K it is paramagnetic, between 102" and 87°K it is antiferromagnetic. and below 87°K it is ferromagnetic (i.e., exhibiting remanence) with a modification of the magnetization occurring at 40°K. The changes in magnetic structure at 102o, 87°. and 40°K are accompanied by shear transformations to successively lower crystal symmetry classes.3 At 102°K a second-order phase transformation to a tetragonal crystal structure occurs. The c/o ratio increases with decreasing temperature to a value of 1.0034 at 87°K where the crystal undergoes another shear transformation to an ortho-rhombic crystal structure. The magnetic modification at 40 K is also accompanied by a shear transformation to a lower crystal symmetry. RbFeF3 is unique in that in the ferromagnetic state it is transparent in the bulk to visible light, has a low saturation magnetization, a large magnetic rotation. and has good optical properties.' All these features make it an ideal material for the investigation of magnetic domain structures in bulk crystals. In addition a dislocation etch has been developed which reveals the point of emergence of dislocations with the (100) surfaces of RbFeF3,5 making it possible to determine the dislocation arrays in the material. As a result domain wall dislocation interactions can be observed in the bulk crystal. In this paper we report on 1) the crystallography of the phase transformations in RbFeF3. 2) the domain configurations as a function of magnetic field and crystal orientation. 3) the interaction of dislocations and magnetic domain walls in RbFeF,. EXPERIMENTAL PROCEDURE Since the temperature range of interest is below room temperature the dewar shown in Fig. 1 was employed. It was designed to fit on the stage of a Leitz panphot metallograph, and permitted examination of the sample at a magnification up to 150 times. The dewar consists of a double-walled glass cylinder bent into an L shape. The space between the walls is evacuated. The viewing wirldows were made of four optically flat quartz discs aligned parallel to each other and sealed to the sides of the concentric cylinders. The specimens were mounted in a holder attached to a flexible plastic shaft. Various holder designs were employed depending upon the type of observations to be made. For studies of the phase transformation between the antiferromagnetic and ferromagnetic state the holder shown in Fig. 2(d) was employed. This holder permitted accurate temperature control at 82" to 88°K by balancing the heat input from the carbon resistance heater against the heat loss to a heat sink immersed in liquid N2. Magnetic field studies were conducted by employing the holders shown in Figs. 2(a) and (b). The holder shown in Fig. 2(n) has a solenoid imbedded in it. such that the magnetic field direction is in the same direction as the incident light. The magnetic field provided by the holder in Fig. 2(b) is perpendicular to the incident light direction. The holder in Fig. 2(r) was employed when observations of the specimen were desired while an elastic bending stress was applied to the sample. The stress was applied to the sample by pulling a wire from outside of the dewar. The wire was attached to a lever pivoted on the holder. which caused the knife edge of the lever to push against the sample. The crystal growth and the sample preparation were described previously.' PHASE TRANSFORMATIONS The first phase transformation in this system is from the cubic perovskite structure to n tetragonal

Jan 1, 1970

By E. Breinan, M. Salkind

Al3Ni whiskers were chemically extracted from unidirectionally solidified Al-A13Ni eutectic ingots, bent into loops, and heated for 0.1 to 10 hr at 320°, 415", and 510°C. The initial strains ranged from 0.003 to 0.055. In all cases, permanent plastic deformation was noted after heat treatment. The deformation consisted of relatively uniform bending at low stresses and temperatures and short times and kinking followed by fracture at high stresses and temperatures and long times. After kinking, the whisker segments adjacent to the kinks were found to have straightened, which is evidence of a dislocation condensation mechanism. The range of temperatures and strains at which time dependent plastic deformation was found indicates that creep of whiskers probably plays a role in the creep of A13Ni whisker-reinforced aluminum. WHISKERS may be defined as nearly perfect single crystals which exhibit high strength. Because they can support high stresses at relatively low strains, they have been successfully employed in reinforcing metals at both ambient and elevated temperatures. In studying the creep behavior of A13Ni whisker-reinforced aluminum at elevated temperatures,1,2 it was noted that the composites exhibited measurable creep deformation. This investigation of the creep relaxation of individual A13Ni whiskel, extracted chemically from the composite was initiated to determine if creep of whiskers could con. "bute to the overall creep of the composite material. Many observations of plastic deformation of metal and halide whiskers have been made. Brenner3-8 noted that copper, silver, and iron whiskers exhibited heterogeneous plastic deformation at room temperature when strained beyond their yield points. Gyulai9 and Gordon10 observed plastic deformation of relatively large (>3 µ) NaCl and KC1 whiskers, although the smallest, most perfect whiskers were completely elastic. Eisner" noted plastic deformation and microcreep of iron and silicon whiskers at room temperature after straining beyond the yield point. Whiskers reported to exhibit creep at stresses below the yield point were zinc1'-" and Silicon.15 Cabrera and price" observed some zinc whiskers which crept at room temperature after a short incubation period but then stopped creeping after a short time. Because some of their specimens exhibited no creep, they concluded that those whiskers that crept were relatively imperfect. Pearson, Reed, and Feldman15 observed similar creep behavior of silicon whiskers at 800°C. They also concluded that creep of the whiskers was a result of imperfections in their crystals. Brenner16 observed delayed failure of A12O3 whiskers at elevated temperatures but found no evidence of plastic deformation up to 2030°C (99 pct of E.EREINAN and M.SALKIND,JuniorMembers AIME,are Research Scientist and Chief, respectively, Advanced Metallurgy Section, United Aircraft Research Laboratories, East Hartford, Conn. Maunscript submitted April 5, 1968. IMD the melting temperature). Brenner also noted7 that some copper and iron whiskers exhibited delayed kinking above 350°C while others did not. One can conclude from these observations that small relatively perfect whiskers could exhibit completely elastic behavior during sustained elevated-temperature loading of composites. Since A13Ni whiskers tested in both bending and tension were found to exhibit no evidence of plastic deformation at room temperature'7'18 this study was initiated to determine whether or not creep of A13Ni whiskers occurred at the elevated temperatures at which creep in the composites was observed. Whiskers were chemically extracted from ingots of unidirectionally solidified A1-A13Ni eutectic, constrained in bending to various elastic strains and heat-treated. The bending constraints were removed after heat treatment and the amount of permanent set was taken as a measure of the time-dependent plastic deformation. EXPERIMENTAL PROCEDURES Ingots of eutectic Al-A13Ni containing nominally 6.2 wt pet Ni were unidirectionally solidified at approximately 11 cm per hr using a process described elsewhere.19,20 The starting materials were 99.99 pct pure. Cylindrical sections cut from the center of each ingot were placed in a 3 pct aqueous solution of hydrochloric acid and the whiskers were extracted as described previously.17 The whiskers nearest the surface were blackened somewhat due to overexposure to the acid while the center of the ingot was being dissolved These partially attacked whiskers were discarded. An intermediate zone of silver-gray-colored whiskers was collected and stored in methanol for use in relaxation experiments. Individual long pieces of A13Ni whiskers were placed on Fisher Precleaned Microscope Slides. These normally straight whiskers were bent elastically into arcs or loops of varying radii by manipulating their ends with a slender probe. The mass attraction between the whisker and the probe was sufficient to cause the whisker to follow the probe. The whiskers were retained in the elastic bend by the surface tension of a fine residual film on the slides. By using long whiskers, the action of the surface tension on the unlooped ends of the whisker allowed high elastic strains to be maintained in the loops. After each whisker was bent, a photomicrograph was taken for use in measuring the bending strain. The range of strains studied was 0.003 to 0.055. The bent whiskers were then encapsulated in Pyrex tubes at pressures between 10"6 and 5 x 10"6 mm of mercury and heat-treated at 320°, 415°, and 510°C (respectively 53, 61, and 70 pct of the peritectic decomposition temperature). After each heat treatment, the liquid film on the slides was found to have dried, but the whiskers were held in their original shapes by a residue on the slide. The minimum radius of curvature of each bent whisker was measured before and

Jan 1, 1969

By R. F. Mehl, W. Batz, C. Wells

Diffusion coefficient values for carbon in austenite covering a wide range of temperature and composition have been determined employing statistical methods. In addition, the relation between concentration and each of the following, D (diffusion coefficient), Q (activation heat of diffusion), and A (the constant in the diffusion equation), has been obtained. A study of the rates of diffusion of austenite was published in Metals Technology in 1940.' The present investigation is an extension of the earlier work, undertaken (1) to obtain values of the coefficient of diffusion, D, over a much wider range of carbon concentration, and (2) to provide data in all ranges of concentration and temperature in such abundance that statistical methods could be employed to evaluate the accuracy of the data with unusual precision. Composition of Materials: Composition of materials used in this research program are listed in table I. These materials, all forged to about 1 1/4 in. rounds, consist of a high-purity iron, Armco iron, a large number of laboratory-made plain carbon steels containing amounts of impurities normally expected in high-quality commercial steels, and three silicon steels. Since it was known at the time these steels were being made that impurities in the amounts present were unlikely to affect carbon diffusion rates' significantly, the effort made to obtain high-purity steels was not as persistent as it otherwise would have been. Procedure: In general, the procedure followed by Wells and Mehl and described' in detail in an earlier publication' is the one used by the present authors. However, certain modifications have been made which it is believed allow diffusion data to be interpreted more objectively and correctly. These are described completely under appropriate subheadings which follow. Experimental Procedure: Experimental procedure includes (1) the preparation of specimens by welding steels of different carbon contents, (2) the heating of these for certain times at selected temperatures in order to diffuse carbon along the specimens across the welded "interface," and (3) the determination of the carbon distribution across the diffusion zone. Preparation of Specimens: Prior to welding steel of one carbon content to iron or steel of another carbon content, surfaces to be welded are machined perpendicular to the longitudinal axis of cylinders which are about 3/4 in. in diam and 1 1/2 in. long. The prepared, flat, parallel surfaces are brought together and butt-welded electrically. Evidence of a good weld is given in fig. 1. Welding temperature

Jan 1, 1951

By James R. Swaisgood, Ronald E. Versaw

Hundreds of shafts have been sunk in the United States in the past. Most of these have been successful however, in some instances thousands of dollars have been lost due to work stoppage while emergency measures were taken to control unexpected water flows. In cases where it was not possible to control the water, the shafts were completely lost. Many thousands of dollars have also been wasted in overconservative support design for the successful shafts. These "hell for stout" designs were necessary because of the importance of the shaft in the operation of the mine. If there was trouble in the shaft, all underground operations would come to a halt. Over-design was also necessary because no reliable preconstruction investigation methods or rational support design methods were available.

Jan 6, 1974