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By J. Rourke, F. S. Minshall, E. G. Zukas, C. M. Fowler, O&apos

The Hugoniot curves were determined for Fe-Si alloys containing up to 7 wt pct (13 at. pct) Si. The pressure of the transition increased as the silicon content of the alloy increased. Single crystals of 2.9 wt pct Si-Fe were also studied. The pressure of the transition was not dependent on crystallo-graphic orientation. All of the Neumann bands (mechanical twins) were attributable to (112) planes but not all of the {112} planes showed twin markings. A thorough study of the iron Hugoniot (the relationship between specific volume and pressure) under plane wave shock loading revealed a pressure transition at about 130 kbar shock pressure. The results of this investigation were reported by Bancroft, Peterson, and inshall1 in 1956. At the time of this discovery, it was felt that this was probably the a, to y transition normally found in iron and many of its alloys. Subsequently a number of iron alloy systems were surveyed in which the alloying element has a considerable effect on the normal a, to y transformation. The influence of carbon and nickel and/or chromium have already been reported.2,3 At the present time, there appears to be some doubt that this pressure transition is the usual a, to y transition In this study, Fe-Si alloys containing up to 7 wt pct (13 at. pct) Si were chosen for several reasons. To the present, the transition has been found only in iron-base alloys which were originally in the a, phase (bcc). Secondly, the y loop at atmospheric pressure extends to only about 2.5 wt pct Si. If the transition were a, to y, then one might expect a rather drastic pressure effect for alloys containing more than 2.5 wt pct Si. Finally, single crystals of Fe-Si alloys large enough for shock loading studies are readily available thereby making it quite easy to determine the effect of crystal orientation on the transition pressure and on the twinning behavior of the alloy. EXPERIMENTAL PROCEDURE Fe-Si alloys containing up to 7 wt pct Si were produced by normal vacuum casting procedures. Single crystals of Fe-2.9 wt pct Si were purchased from Monocrystals Co., Cleveland, Ohio. The orientations of these crystals were determined and samples cut so that the shock wave would be parallel (to within 1.5 deg) to either the (loo), (Ill), or (112) principal orientations. Three distinct experimental testing techniques were used. First, the pin technique, described elsewhere,4 was used to determine the transition pressure for the polycrystalline alloys as well as for the (111) and (112) orientations of the 2.9 wt pct Si single crystals. Secondly, the recovery studies, described in detail in an earlier paper,2 were used for determining the effect of alloy composition and crystal orientation on the plastic II compression-plastic I rarefaction interaction zone for several specific shock pressures. Finally, measurements of pressures above the two-wave threshold were made on the polycrystalline alloys so that more complete Hugoniot curves could be constructed for this alloy system. The optical techniques described by Rice et al.5 were used to measure the shock and free surface velocities of the samples from which the Hugoniot data were obtained. This method is applicable only in the single wave region, since velocities are obtained from the measured total transit times of the disturbances through measured sample thicknesses.

Jan 1, 1963

By R. W. Gurry

In a series of charts this paper presents the composition of all gas mixtures, composed of the elements carbon, hydrogen, oxygen and nitrogen, which at temperatures from 1000° to 1800°F are in equilibrium with (1) austenite of various carbon contents, (2) iron and iron carbide, (3) graphite, (4) iron and its oxide. THIS paper presents the results of calculations made to determine the proportions of CO, CO2, CH4, H2, H2O and N2 in gas mixtures which, at temperatures from 1000" to 1800°F, satisfy, individually, the following conditions: (1) equilibrium with carbon steel of specified carbon content throughout the stable 7 iron region; (2) equilibrium with iron and iron carbide, both above and below the eutectoid temperature; (3) equilibrium with graphite; (4) equilibrium with iron and its oxide. From these data a new type of chart has been prepared which permits one to determine, from a room-temperature analysis of the furnace gas in question, the effect of the gas upon the steel at furnace temperature. Thus a guide is provided as to the carbon content which will result and as to the possibility of oxidation or sooting. All of the atmospheres commonly used in the commercial heat treatment of steel are composed of some or all of the simple constituents CO, CO2, CH4, H2, H2O and N2, and also in some cases oxygen or higher hydrocarbons. As the gas mixture is heated certain alterations in the proportions of the constituents take place, and at the temperature of the furnace the composition is, in general, not at all that of the entering gas. If equilibrium in the gas phase is presumed a calculation involving the use of certain fundamental data predicts for a certain temperature the carburizing, decarburizing, or sooting characteristics of a given atmosphere, and, upon the additional assumption of equilibrium between gas and metal, also the oxidizing ability of the gas and the ultimate carbon content of the steel. The extent to which these predictions are fulfilled will depend upon how closely the assumptions of equilibrium are realized in any particular case. Although at lower temperatures equilibrium is often not reached, there is considerable evidence indicating that above about 1000°F the approach to equilibrium in the gas phase is generally substantially complete, particularly in the vicinity of the steel which acts as a powerful catalyst in promoting reactions in the gas phase. The extent of the gas-metal reactions is commonly affected essentially by the sojourn at temperature; equilibrium with respect to carbon, for example, is accomplished simply by continuing the treatment long enough. However close the approximation of equilibrium may be in any instance, the above mentioned calculation indicates the condition of the steel at equilibrium, and at the present time this is the only basis of control of a furnace atmosphere. The effect at elevated temperature of a gas of a certain composition at room temperature upon a given steel has customarily been judged by first calculating from gas equilibrium constants the proportions of the gas constituents at the temperature of the steel, then comparing certain of these with the proportions known to be in carbon or oxygen equilibrium. This process is tedious and time-consuming, in particular because the calculation generally involves a series of successive approximations; and since some knowledge and familiarity with this type of computation are required, not everyone needing the information has been, in the past, in a position to obtain it. By making a series of equilibrium calculations, combining with fundamental data for gas-metal reactions, and plotting the results in a special way, a chart has been prepared which enables anyone

Jan 1, 1951

By A. S. Eve

IN the spring of 1930, the question was raised as to the possibility of estimating the depth to which the pyrrhotite-nickel deposit at the Falconbridge mine extended in the earth. This body is 7500 ft. long, it dips at 80° to the north, and it is fairly straight with slight sinuosities. Dr. F. W. Lee suggested that it might be possible to solve the problem by measuring the vertical magnetic intensity, with a good magnetometer, both near the surface of the earth and also at a level a 'few feet higher in the air. The writer regarded this suggestion with some scepticism, but it was decided to put the scheme to a prac¬ tical test. In July, 1930, Dr. Lee, Dr. Keys and I ' the writer, with Mr. Joyce and Mr. Belloc as assist¬ ants, made a firm, light wooden platform (Fig. 1) E measuring 4 by 4 ft. on the top, which was 10 ft. above ground. This platform could be moved easily a few yards by four men, and carried across I country in a wagon or by motor truck. Some iron nails were used in its construction, but we were not able to detect their influence on the - Askania magnetometer. Nevertheless, in future work, the use of iron should be completely avoided. Readings were taken along a traverse at right L angles to the orebody, at several stations, both on FIG. 1.-VERTICAL the ground and on the platform. The excess read- ASKANIA MAGNETOM¬ ETER ings, over the dike, as compared with those about 10 ETER ON A FT. HIGH. PLATFORM 800 ft. away, are shown in Table 1. The largest reading, 6.8, is open to suspicion and should be rejected. The depth of the top of the orebody is known by electrical survey, and by actual drilling, to be about 112 to 123 ft., and the covering is sandy glacial drift. Similar readings were taken over a long straight magnetic diabase dike. These also are shown in Table 1. The magnetic vertical intensity is consistently less at the higher level, which is l0 ft. above the lower level.

Jan 1, 1931

By William G. Pariseau

Advances in numerical methods of analysis and computer technology during the past decade have brought many formerly intractable ground control problems within easy reach of present day graduate mining engineers. However, the new technology brings with it new problems. The identity of these problems are largely those arising from a lack of familiarity with the capabilities and limitations of the new technology. In this regard, the central problem in ground control planning is the calculation of ground motion associated with mining. The fundamentals of this problem leading to a form suitable for computer programming are therefore reviewed. Solution procedures in the broad sense including the gathering of input data and the interpretation of output are described. Computer program capabilities necessary for ground control analysis are discussed and the steps necessary to implement an analysis are outlined.

Jan 1, 1983

By William A. Bassett

Two very intense sources of electromagnetic radiation are contributing significantly to experimental studies of minerals at high pressures and temperatures: 1) A Q-switched YAG laser is able to produce a pulse of infrared radiation capable of heating a sample under pressures up to 400 kbar in a diamond cell up to temperatures in excess of 4000°C. 2) X-rays from the Cornell High Energy Synchrotron Source (CHESS) are used to obtain diffraction patterns of samples In a diamond cell in less than two minutes, patterns that would require hundreds of hours on a conventional source. The laser heating technique is being used to study the pressure-temperature conditions over which the melting of diamond takes place. In the initial stages of this investigation, diamond has been melted and techniques for detecting the melting have been developed. The intense X-rays from the synchrotron source have been used to examine the mechanism and rate of the pressure-induced phase transformation in Fe2Si04.

Jan 1, 1985

Only the coal of the Sunnyside district in Carbon county is coked. Two companies, the Utah Fuel Company and the Columbia Steel Corporation, operating adjoining mines at Sunnyside and Columbia, produce coke. The Utah Fuel Company has 81 9 beehive coke ovens at Sunnyside. Only 350 ovens are being operated at the present time, largely because the smelters which had been using Sunnyside coke changed their equipment from blast furnaces to reverberatory furnaces

Jan 1, 1925

By Lewis W. MacNaughton

The North Texas district, as herein defined, includes the counties of Archer, Baylor, Clay, Cooke, Foard, Hardeman, Knox, Montague, Wichita, and Wilbarger. This area covers generally the crest and south flank of a system of buried mountains known as the Red River uplift. The oil and gas accumulations along this feature arc in traps, which, although localized by structures incident to the regional uplift, are usually modified by stratigraphic changes in the sediments. Excepting the fields in southeastern Baylor, southern Archer, and southwestern Clay counties, all the fields within the district are on this Red River uplift. These exceptions, which have the same type of oil and gas accumulation as the other fields, are on the extreme north end of the Bend arch, which is a broad anticline plunging northward from the Llano uplift in central Texas to Archer County. The larger part of past oil and gas production has come from Pennsylvanian strata, with less important amounts from the Permian, and minor but increasingly important quantities from the Ordovician. Developments during 1939 With the later stages of development being reached in the K.M.A. field during the first half of the year, some 400 fewer producing wells were drilled in North Texas in 1939 than in 1938, when some 1750 wells were drilled. Despite this decrease in activity, production in 1939 increased about 3½ million barrels over 1938 figures, and at the end of the year the oil reserves were somewhat larger than on the first of the year. As is usually characteristic of the district, this resulted from the discovery of a large number of relatively unimportant fields. Owing principally to no appreciable abatement in wildcat drilling, more new fields and extensions to old fields were discovered this year. Although none of these discoveries was of such magnitude as to be important to the oil industry, the new developments in Montague and Cooke Counties portend greater and probably more important operations in these areas.

Jan 1, 1940

By Lewis W. MacNaughton

The North Texas district, as herein defined, includes the counties of Archer, Baylor, Clay, Cooke, Foard, Hardeman, Knox, Montague, Wichita, and Wilbarger. This area covers generally the crest and south flank of a system of buried mountains known as the Red River uplift. The oil and gas accumulations along this feature arc in traps, which, although localized by structures incident to the regional uplift, are usually modified by stratigraphic changes in the sediments. Excepting the fields in southeastern Baylor, southern Archer, and southwestern Clay counties, all the fields within the district are on this Red River uplift. These exceptions, which have the same type of oil and gas accumulation as the other fields, are on the extreme north end of the Bend arch, which is a broad anticline plunging northward from the Llano uplift in central Texas to Archer County. The larger part of past oil and gas production has come from Pennsylvanian strata, with less important amounts from the Permian, and minor but increasingly important quantities from the Ordovician. Developments during 1939 With the later stages of development being reached in the K.M.A. field during the first half of the year, some 400 fewer producing wells were drilled in North Texas in 1939 than in 1938, when some 1750 wells were drilled. Despite this decrease in activity, production in 1939 increased about 3½ million barrels over 1938 figures, and at the end of the year the oil reserves were somewhat larger than on the first of the year. As is usually characteristic of the district, this resulted from the discovery of a large number of relatively unimportant fields. Owing principally to no appreciable abatement in wildcat drilling, more new fields and extensions to old fields were discovered this year. Although none of these discoveries was of such magnitude as to be important to the oil industry, the new developments in Montague and Cooke Counties portend greater and probably more important operations in these areas.

Jan 1, 1940

ZAY JEFFRIES (written discussion*).-I have read with much interest Mr. Ruder's discussion of Professor Howe's paper, "The Supposed Reversal of Inheritance of Ferrite Grain Size from that of Austenite." I am yet of the opinion that my first explanation' of Mr. Ruder's samples is substantially correct. In that explanation I did not intend, however, to convey the impression that "reversed inheritance" was the general rule nor even of common occurrence but rather that." Non-inheritance" was the general rule. Mr. Ruder suggests that a " perfectly formed" grain is an indication of inheritance. The grains in my Fig. 52 are perfectly formed and in fact more nearly equiaxed than those in Mr. Ruder's Fig: C,3 yet the grains in the former are known not to be inherited but to have been formed by the partitioning of larger austenite grains. On close examination of Mr. Ruder's Fig. C the very shapes of the grain suggest partitioning. Again, the grain size (25 to 30 grains per square millimeter) is at least 10 or- more likely 20 times smaller than might be expected of the austenite from which these grains were .formed under the given time and temperature conditions. Mr. Ruder's newer results on electrolytic and Armco iron are most interesting and instructive. His results fit in. nicely with my conclusions 5, 6 and 10.4 His photographs, however, indicate that the thickness of the pieces of sheet metal are such that abnormal grain growth is promoted. He indicates that equilibrium grain size after heating to 950° C., with furnace cooling, is about the same as his Fig. 1, above. I estimate this to be approximately one-half -grain per square millimeter, or 40 times as large as I have obtained with the same material (Armco iron) after heating Y4-in. bars to 1300° C. for 2 hr. and cooling in the furnace. The effect of thickness of sample on grain size is one which needs more attention.

Jan 3, 1918

[ ] TUNNELS TO BINS. Originally designed for tunnel work, the strong lightweight liner plates used to construct this 30-ft diameter, 31-ft high, aggregate storage bin have several advantages. Bins and conveyor to tunnels can be quickly erected in any season, for permanent service, or to be salvaged and reused. Armco Steel Corp. (16) ROLLER CHAIN: Engineering Data Book No. 2457 published by Link-Belt Co. is a comprehensive 148-page volume on roller chain and its application. Detailed engineering information covers installation, maintenance and lubrication of chains for drives, conveyors, and sprocket wheels. The book covers selection of drives to meet both standard and special installations. (17) LABORATORIES: The Fisher Scientific Co's. line of 21 basic units of standardized steel laboratory furniture is described in catalog no. 25. The Unitized line was designed to combine the advantages of custom installation with the convenience of selection, delivery and continued flexibility that goes with ready-made units. (18) PUMPS: Two similar, but functionally different types of vertical centrifugal wet-pit pumps; a heavy duty bilge pump for handling solids-free liquids and drainage; and a screenless sewage ejector, constructed to handle sewage and solids carrying liquid; are illustrated in a bulletin from Yeomans Bros. Co.

Jan 1, 1952

By Carl A Zapffe, George A. Moore

In a previous publication from this laboratory1 the conclusion was drawn that the embrittling effect of occluded hydrogen on iron and steel must result from the precipitation of the gas within small openings through the crystal structure. A review of the literature then published indicated the real existence of crystal substructures of the mosaic type and gave presumptive evidence that the "rift openings" associated with hydrogen occlusion are the same as the L'disjunctions" of the mosaic theory. Inasmuch as no clear conception of the actual nature of the crystal fragments and openings inherent in these theories has been established, it was considered desirable to obtain direct micrographic evidence of their true configuration. In this direction the standard methods of metallographic attack have proved useless. Recourse was had, therefore, to the direct examination of the surfaces upon which failure by cleavage had resulted from the presence of hydrogen. It was expected that such a surface, unaffected by chemical attack and undis-torted by polishing, would reveal the fine openings penetrated by the gas and thus indicate the real nature of the substructures. Materials Studied In commercial steels, defects caused by hydrogen take various external forms according to such factors as structure and purity, and to the extent to which hydrogen either occludes or produces chemical changes. The present work relates only to the well-known transcrystalline hydrogen embrittlement—-"pickling brittleness "—in which elemental hydrogen occluded within the grain develops cleavage characteristics. For example, hydrogen embrittlement resulting from hydrogen reaction products is excluded from detailed study. It was also desirable, as far as possible, to have the study uncomplicated by other elements which themselves cause brittleness. Three types of iron were used. These included ingot iron, decarburized free-machining steel, and a specially prepared, aluminum-killed, electrolytic iron. This choice allowed a comprehensive selection of unavoidable minor impurities and inclusions, which could subsequently be shown to have no specific effects on the structures within the grains. Carbon, and any other impurities free to react with hydrogen, were first removed by a preliminary annealing treatment in hydrogen. Subsequent treatment in vacuo extracted much of this hydrogen and its gaseous reaction products. The resultant ductile iron was then embrittled either by a second anneal in hydrogen, followed by rapid cooling, or by cathodic electrolysis. Group 1: Prepared from Armco Ingot Iron As shown in Table 1, the principal impurity in this iron was oxygen, which survived the purifying treatment to a large extent. Two series were prepared. The first (Nos. SIO-24) was purified only one day in hydrogen and dehydrogenized one day in nitrogen. Containing both hydrogen and its

Jan 1, 1943

By Carl A. Zapffe, George A. Moore

In a previous publication from this laboratory1 the conclusion was drawn that the embrittling effect of occluded hydrogen on iron and steel must result from the precipitation of the gas within small openings through the crystal structure. A review of the literature then published indicated the real existence of crystal substructures of the mosaic type and gave presumptive evidence that the "rift openings" associated with hydrogen occlusion are the same as the L'disjunctions" of the mosaic theory. Inasmuch as no clear conception of the actual nature of the crystal fragments and openings inherent in these theories has been established, it was considered desirable to obtain direct micrographic evidence of their true configuration. In this direction the standard methods of metallographic attack have proved useless. Recourse was had, therefore, to the direct examination of the surfaces upon which failure by cleavage had resulted from the presence of hydrogen. It was expected that such a surface, unaffected by chemical attack and undis-torted by polishing, would reveal the fine openings penetrated by the gas and thus indicate the real nature of the substructures. Materials Studied In commercial steels, defects caused by hydrogen take various external forms according to such factors as structure and purity, and to the extent to which hydrogen either occludes or produces chemical changes. The present work relates only to the well-known transcrystalline hydrogen embrittlement—-"pickling brittleness "—in which elemental hydrogen occluded within the grain develops cleavage characteristics. For example, hydrogen embrittlement resulting from hydrogen reaction products is excluded from detailed study. It was also desirable, as far as possible, to have the study uncomplicated by other elements which themselves cause brittleness. Three types of iron were used. These included ingot iron, decarburized free-machining steel, and a specially prepared, aluminum-killed, electrolytic iron. This choice allowed a comprehensive selection of unavoidable minor impurities and inclusions, which could subsequently be shown to have no specific effects on the structures within the grains. Carbon, and any other impurities free to react with hydrogen, were first removed by a preliminary annealing treatment in hydrogen. Subsequent treatment in vacuo extracted much of this hydrogen and its gaseous reaction products. The resultant ductile iron was then embrittled either by a second anneal in hydrogen, followed by rapid cooling, or by cathodic electrolysis. Group 1: Prepared from Armco Ingot Iron As shown in Table 1, the principal impurity in this iron was oxygen, which survived the purifying treatment to a large extent. Two series were prepared. The first (Nos. SIO-24) was purified only one day in hydrogen and dehydrogenized one day in nitrogen. Containing both hydrogen and its

Jan 1, 1943

By H. S. Choi, I. Iwasaki

The effect of temperature as a parameter in ore flotation has not been systematically studied, although for some ores it has been known for many years that selectivity and grade of concentrates can be improved by conditioning or flotation at moderately or substantially elevated temperatures. In 1934 Coghill and Clemmer' stated that "elevated temperature seems to make hard water more tolerable" in soap flotation, and a cursory examination of the literature indicates that some earlier investigators were aware of beneficial results obtained by floating above room or mill-water temperatures. Tartaron,2 Mitchell et aL.,3 and particularly Hamilton et al.' have shown that high pulp temperatures give high recovery and selectivity in soap flotation of fluorite from a variety of gangue minerals. As a result of the work of these and of other investigators, high-temperature flotation has been successfully applied to industrial flotation of fluorite. Falconer" stated: "The use of high temperature conditioning (above 35°C and preferably above 60°C) in connection with the soap flotation of nonsulphide ores, as covered in B. Kalinowski's French Patent No. 847,-215, Dec. 7, 1938, is claimed to provide more intense activation, better separation of values from gangue, and reduction in quantity of reagents." The various investigations quoted above clearly demonstrate the improvements to be realized by increasing the temperature at which fluorite is floated, and it is surprising that little or no information has been published on systematic investigation of the same method as applied to other ores. The present article describes comparative results obtained at room temperature and at elevated temperatures by otherwise conventional flotation of iron ores, by single-mineral flotation in the Hallimond tube, and by contact-angle measurements. It is not the purpose of this article to evaluate the commercial feasibility of high-temperature flotation of iron ores, although preliminary calculations show that the cost should not be excessive and that the gains to be realized may well outweigh the extra cost of heating the pulp. LABORATORY FLOTATION TESTS Experimental: All flotation tests reported in this article that use a laboratory Fagergren cell were made on ore A (either containing the primary slimes or deslimed at 20µ as specified) following the preparatory procedures described elsewhere- or this particular ore. Ore A contained hematite, goethite (limonite), quartz, chert, and minor quantities of magnetite. Confirmatory tests made on other ores show that the same general principles apply to ores of similar mineralogy and structure. Conditioning was performed by adding the collector, as a soap, to the vigorously stirred and heated pulp. Conditioning time was 5 min, the pulp contained 60 pct solids, and the equivalent of 0.5 Ib of fatty acid was added per ton of original (unde-slimed) ore. The pH of the pulps ranged from 6.8 to 7.1 (25°C measurement) during conditioning. The pH was adjusted in the flotation cell by addition of either NaOH or H2SO4, the values reported being those of the pulp cooled to 25°C. During conditioning and flotation the pulp temperatures were controlled within l° to 2° by immersion of Variac-controlled Calrod elements in the conditioning beaker and in the cell, and by the use of water, heated to the appropriate temperature, for transferring pulp, adjusting pulp volume, and washing. Selectivity indexes have been calculated on the same basis as those reported in the article by Cooke, Iwasaki, and Choi." Results: Table I gives the results obtained by floating deslimed ore A with pure oleic acid at 25" and 50°C, and Fig. 1 shows the selectivity indexes plotted against pH of flotation. Inspection of Table I

Jan 1, 1961

By W. Vickers

Single-point rotating cantilever fatigue tests have been carried out at 550" to 650°C on beryllium produced by a variety of fabrication routes. All the specimens gave similar plots of stress against number of cycles to failure but failure occurred at a lower stress range in the hot-pressed material than in the extruded material. A discontinuity or "kink" appears to exist in the curves and this is considered. A true endurance limit was not evident up to 10 cycles. When Brush hot-pressed warm-extruded beryllium was tested at 600oC a relationship where Nf = number of cycles to failure, ?ep = plastic strain range, and c = constant, was shown to be applicable for values of ?ep > 6.3 x 10-4. Further for this moterial and temperature and for frequencies between 150 and 4500 cycles per min, the variation of number of cycles to failure with frequency obeyed the expression N = Af0.44 where N =number of cycles to failure, f = frequency, and A = constant. Examination of the fracture surfaces indicated that they were generally intergranular and in all cases the higher the stress the more irregular was the fracture. Microexamination has shown that grain boundary cavities and fine intergranular cracks were associated with the fractures. REVERSING or cyclic stresses set up in fuel elements can lead to failure by fatigue. Fatigue stresses may be developed by instability of the fuel element in the coolant flow leading to rattling against the channel wall or fin vibration. Thermal cycling also sets up reversing stresses due to differential expansion of fuel and can. Fatigue resistance is of some importance therefore in the evaluation of canning materials. At the time the work described in this paper was initiated, beryllium was being considered for the can and endcaps of an advanced gas-cooled reactor fuel element. With this in mind, beryllium obtained from different manufacturing routes was tested on single-point rotating cantilever fatigue machines at temperatures the same as those envisaged in the reactor to obtain appropriate fatigue data. The results obtained indicated a discontinuity in the S-N curves coinciding with the yield stress in the specimens. Although in some cases the data is insufficient to warrant a detailed quantitative analysis, a qualitative analysis of this effect was thought to be justified. 1) EXPERIMENTAL DETAILS The materials used are given in Table I together with the production route and available analyses. The specimen shape is shown in Fig. 1. The fatigue specimens were machined slightly oversize, after which they were given a stress-relieving anneal of 1 hr at '750° C in vacuum. This was followed by an etch in sulfuric-phosphoric-chromic acid mixture down to the finished dimensions given in Fig. 1. Etching served to remove the interference colored oxide film formed on the surface during annealing and very small recrystallized surface grains too. The specimen was mounted in the grips of a cantilever machine and rotated inside a furnace controlled at the testing temperature. The specimen was loaded in increments as the speed was increased until the required load was applied at 5000 cycles per min. A revolution counter was used to record the total number of cycles.

Jan 1, 1964

By P. A. Young

The historical background of on-strand cooling is given, together with a resume of recent practical developments. Laboratory test procedures are then considered in detail, for both productivity and quality parameters, with particular reference to the design of the Ravenscraig No 3 machine (Scotland). A heat transfer model is presented for a porous sinter with propagating cracks. The influence of cooling/sintering area ratio, sinter strength, granulometry, return fines, coke consumption and FeO levels are examined in relation to economics. A detailed comparison of capital and running costs for two different strands, designed for identical duties, but with off or on-strand cooling, is then given.

Jan 1, 1977

By S. F. Emmons

It was said by many who discussed Professor Posepny's admirable paper on the "Genesis of Ore-Deposits," read at the Chicago meeting of the Institute, in 1893, that its most valuable feature was the clear distinction which it drew between the influence upon ore-deposits of the " vadose " circulation of waters descending directly from the surface, and that of the deep underground circulation of waters generally coming from the depths, and assumed by the author to be ascending through more or less open spaces under the influence of heat. A little later the effect of the oxidizing action of the vadose circulation upon ore-deposits was ably and exhaustively treated by Prof. R. A. F. Penrose, in a paper on " The Superficial Alteration of

Jan 1, 1901

By William H. Callahan

"For his exceptionally successful career as a geological mentor, for his ore-finding skills, and particularly the discovery of the Central Tennessee Zinc District and for his lecture, 'Prospecting in the USA-Promise and Problems.' " Recipient of the 1982 D.C. Jackling Award

Jan 1, 1983

By James F. Magee

There is nothing new about dragline dredging for placer gold. The use of the separate unit for excavating preceded the large barge with excavator mounted upon it, which has reached a high state of perfection through use in every part of the world. But at present there is a vogue for a small, inexpensive plant combining a dragline excavator on caterpillar mounting and a gravel-washing plant on a floating barge. The most efficient ones use a bucket of 1 to 2 yd. capacity with boom from 40 to 70 ft. long. The barge varies from 20 by 30 ft. to 36 by 48, and carries the trommel screen, pump, riffle sluices and power engine. Plants in Oboville District In the Oroville district eight such plants have been built since 1933, and have been operated with varying success. The most successful of these is the plant of the Wyandotte Gold Dredging Co. This organization of six active partners constructed its first plant on Wyandotte Creek in the autumn of 1933. To September of 1935 about one million cubic yards of gravel was dredged for an output of about $225,000 in gold. The operation has been successful from the beginning, because of wise management, which was based upon good plant design and proper principles of operation. All the partners have taken a more or less active part in the operation. Usually there is one at work on each shift, and they have conducted their own prospecting and building also. They elected H. F. England as manager, with wide power of control, and he carries out this responsibility energetically and successfully. One of the other plants, started shortly before the Wyandotte, finally abandoned its operation and sold its ground to the latter company, which successfully worked it for a profit. The failure of the other plant was due principally to poor excavating equipment. Another organization that built a plant some months later than the Wyandotte company had considerable difficulty in management and was unable to keep ahead of expenses. Finally, late last summer, it entered into an agreement with the Wyandotte company to have the latter supply

Jan 1, 1937

By W. A. Tiller

The unidirectional freezing of a semiinfinite liquid from one end has been treated by calculating the solute and temperature distributions in the liquid and solid phases with time, when the solid-liquid interface advances at a rate proportional to (time)lt2. The nucleation probability for new grain formation is calculated as a function of the constitutional and thermal properties of the alloy, the pouring conditions and the catalytic efficiency of the nucleating agents. The transition from columnar crystal formation to equiaxed crystal formation is assumed to occur at a critical nucleation frequency for a particular alloy and the quantitative dependence of the ratio (columnar zone length/equiaxed zone length) upon the freezing conditions has been predicted. The effects of (i) fluid flow in the liquid, (ii) heat transfer through a mold wall, and (iii) a finite ingot length, have been explicitly tveated as departures from ideality. These departures from ideality are found to have very important consequences on the ingot stmcture. In Part I&apos; of this series, a qualitative description of the general ingot structure was developed. The factors that determine i) the ratio of the equiaxed zone length to columnar zone length and ii) the grain sizes in these zones, were discussed. In the present paper, topic (i) will be treated quantitatively, and it is intended that topic (ii) will be treated quantitatively in Part 111. The complete treatment has been split in this manner for ease of development and coherency of presentation. The treatments are quite mathematical in nature and, although some of the conclusions to Part 11 depend upon the treatment presented in Part 111, it was felt that the intended audience would find the material more readable and more useful in its present form. To this same end, it seems worthwhile to reiterate some of the qualitative aspects of grain nucleation during ingot solidification before embarking on the mathematical description. QUALITATIVE ANALYSIS In the conventional method of casting, a liquid alloy with a certain degree of superheat is poured into a mold. The outer rim of liquid metal cools rapidly to the liquidus temperature of the alloy and begins to undercool. As the degree of undercooling increases, nuclei of solid begin to form in this chill layer, this nucleation being catalyzed by certain heterogeneous particles in the liquid. The grains in the chill layer which are generally of random orientation, begin to grow inwards because of heat conduction through the mold. The grains usually develop a columnar shape since the frequency of nucleation of new grains in the liquid ahead of the advancing interface is generally insufficient to seriously impede the growth of the original grains. Due to the slow diffusion rate of solute in the liquid, a solute distribution is formed in the liquid adjacent to the interface which is either an excess or a depletion if the partition coefficient, ko, of the solute is < 1 or > 1, respectively. Thus, the liquidus temperature of the liquid adjacent to the interface is a function of position. The actual temperature in the liquid is also a function of position and the temperature gradient at the interface decreases as the interface moves away from the mold wall. Since the rate of advance of the interface decreases with time, the equilibrium temperature distributions and the actual temperature distributions as a function of interface position, X, can be illustrated as in Fig. 1. Thus, a region of liquid may exist in which the actual temperature is below the liquidus temperature. This liquid is contitutionally supercooled and therefore unstable with respect to the nucleation of new grains. Now, since the supercooling in Fig. 1 increases as the interface moves further away from the mold wall, the nucleation rate of new grains will increase. When the nuclea-

Jan 1, 1962

THE fall meeting of the Petroleum Division at Fort Worth, Texas, Oct. 19 and 20, attracted even a larger number of members and guests than had been expected. Over three hundred registered the first day though the attendance and interest in the program was so keen that it was necessary to begin technical sessions without. waiting for registration. Members were present from as far away as Venezuela and while the larger attendance was from the Mid-Continent and Texas fields, California and the eastern states were represented by influential delegations. One pleasing feature of the meeting was the presence of a number of the older executives of the oil industry who evi-dently have come to realize the importance of the work the Division is doing in advancing technology. The meeting was held under the auspices of the Production Engineering section of the Division. E. 0. Bennett, chief production engineer for the Marland Oil Co. of Texas, and chairman of the Fort Worth Sec-tion. of the A.I.M.E., served as general chairman. J. B. Umpleby, president of the Petroleum Reclamation Co. and vice-chairman of the. Division was in charge of. the program with a special committee in charge of the technical sessions, of which A. C. Rubel of the Union Oil Co. was chairman. The sessions were held in the ball room of the Texas Hotel, which also served as general headquarters. The Wednesday morning session was devoted to the air-gas lift, John M. Lovejoy, chairman of the Division, presiding. The first paper, on the "Principles Under-lying the Air-Gas Lift." by J. 0. Lewis, was presented by R. R. Brandenthaler and discussed by Messrs. Love-joy and Millikan. Mr. Brandenthaler&apos;s own paper on the "Effect of Gas Lift on Physical Properties of Oil" followed and was discussed by Messrs. Umpleby, Walker, Mills, Bennett, Williams and Van der Gracht, the dis-cussion turning mainly on what is known and what unknown regarding oxidation of oil under various con-ditions. The third paper of the morning, "Handling Recirculated Gas," by R. D. Gibbs, was presented by Mr. Taylor. The discussion that followed was general and brought out a large amount of data on the costs and results of compression versus, absorption in total gasoline recovery from gas. The next group of papers dealt with "Mechanical Installations of Air-Gas Lift," the first by E. V. Foran on the Texas district outside the Gulf Coast, the second by L. L. Brundred on the Gulf Coast, the third on Kansas and Oklahoma other than Seminole by R. W. Bond, the fourth on Seminole by C. R. Swartz, and the fifth relating to California by H. C. Miller. Some of these were read by title in order to give more time for discussion which was active and participated in by. Mills, Griswold and others.

Jan 11, 1927