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By S. G. Valentine

BLAST-FURNACE blowing engines are broadly of two main types: either steam- or gas-driven reciprocating engines, or turbine-driven rotary engines. Some results of experience with a furnace blown by an engine of the latter type may be of sufficient general interest to relate. The first engine of this type was installed at Oxford Furnace, New Jersey, before the writer's connection with this plant, in March, 1910. This furnace uses chiefly New Jersey magnetites and had been in blast seven months on its old engines when the turbo blower was started. It was 80 ft. high by 17 ft. 6 in. bosh and 11 ft. hearth diameter. It is of interest to see from the records what happened when the turbo engine was put to work. But of course, as the old blowing equipment was rather antiquated, consisting of two I. P. Morris engines with air cylinders 72 by 72 in., in good running order, however, it is evident that the comparison between their work and that of the turbo blower cannot be interpreted as being between machines that were respectively of equal excellence as representatives of their types. Still the results were gratifying and -interesting. The records show that, with the old engines blowing 13,630 cu. ft: of air per minute, measured by piston displacement, the furnace was working up about 480 tons of stock per 24 hr. and producing an average of 132 tons per day and a maximum of 166 tons. The rotary blowing engine installed was a General Electric Co. machine, the driving end being a Curtis steam turbine and the air end a six-stage rotary compressor, all running at about 1,500 to 1,600 rev. per minute, and having a capacity of 25,000 cu. ft. of air per minute up to 25 lb. pressure, and equipped with an automatic constant-volume variable-speed governor. After running this blower, for a period equal to that covered above by the old engines, at an average rate of 15,000 cu. ft. of air per minute, the furnace worked up an average of about 592 tons of material and produced an average of 170 tons per day. Thus, on an apparent increase of 10 per cent. in the air volume there was an increase of about 23.5 per cent. in the materials worked up and of about 28.8 per cent. in the product. For the first calendar month's operation of the turbo blower, on an average of 15,040 cu. ft of air per minute, there is

Jan 2, 1914

West Virginia Geological Survey Morgantown, W. Va James D. Sisler, State Geologist. Of great importance among the publications of this Survey have been the volumes of Detailed Reports on the counties of the state These volumes take up in detail the geology, topography, soils and resources of the areas under consideration; they are profusely illustrated and each carries topographic and geologic maps Detailed Reports are available for areas as follows: Marshall, Wetzel and Tyler counties (1911) $3, Wirt, Roane and Calhoun counties (1911), $2 50, Jackson, Mason and Putnam counties (1911), $2, Cabell, Wayne and Lincoln counties (1912), $2 50, Doddridge and Harrison counties (1912), $2 50, Monongaha, Marion and Taylor counties (1913), $2 50, Kanawha County (1914), $2 50; Preston County (1914), $2, Logan and Mmgo counties (1915),12 50, Boone County (1915), $2, Wyoming and McDowell counties (1915), $2 50, Lewis and Gilmer counties (1916), $2 50; Raleigh County, Summers west of New River, and the coal area of Mercer County (1916), $2 50, Jefferson, Berkely and Morgan counties (1916), $2 50, Braxton and Clay counties (1917), $2 50; Barber and Upshur counties, and western Randolph County (1918), $3; Fayette County (1919), $3 25;

Jan 1, 1933

By P. W. George

THE rapid increase in cost of discovering new orebodies by churn drilling in the Tri-State district has led to some attempts to lessen the expense by using geophysical methods. Electrical prospecting was tried three or four years ago, but no successful results were recorded. In 1926, the Federal Mining and Smelting Co. engaged the North American Exploration Co., of Houston, Texas, to make some tests with the torsion, balance. At first, it was thought that the most favorable conditions for discovery of ore deposits with the torsion balance would be in locations where the ore was known to occur at rather shallow depths, FIG. 1.-CROSS-SECTION OF DUENWEG LEASE. therefore the first trial was made at Duenweg, east of Joplin, where some zinc ore had been developed at a depth of 130 ft. The gravity gradients at 61 stations on a tract of about seventeen acres indicated plainly one large zone of maximum gravity and a smaller narrow zone of minimum gravity. Fourteen churn-drill holes, half of which struck .ore, show that all the ore found was located outside the zones of maximum and minimum gravity. In the zone of maximum, gravity the limestone beds were closest to the surface, and the first chert beds encountered were at the greatest depth. The results (shown in Table 1) indicated that the gravity of the limestone was greater than the gravity of the fractured chert together with its orebodies, and probably also greater than the bouldery soil and clay on top of the limestone. A cross-section of the Duenweg lease is shown in Fig. 1.

Jan 1, 1928

By Arthur Taggart

FOREWORD THE tests herein described are part of an extended series of experiments, performed by the authors together with J. F. McClelland and L. W. Bahney, on the reclamation of metallics from foundry and manufacturing-plant scrap. The most obstinate problem encountered was the proper cleaning of the metal. INTRODUCTION In the manufacture of brass and brass products the weight of the finished product leaving the plant is much less than the total weight of copper and zinc entering. A small part of this discrepancy is due to the unavoidable oxidation of the metals in melting, but by far the largest part of the loss is in the form of metallic particles of copper, zinc, and brass. These losses occur principally at three points in the process: (a) in the casting-shop ashes; (b) in the slags from furnaces melting scrap brass; (c) in material spilled on the floor throughout the manufacturing process. The amount of these products in some plants is nearly 100 tons per 24 hours. Casting-shop ashes contain the metal spilled from the crucibles during melting and pouring, and the metal included in the slags formed in the melting process. The ashes also contain pieces of broken crucibles with adhering metal; 20 to 30 per cent. of unburned coal is also present. The metal in casting-shop ashes contains clean pieces of zinc or copper ingots weighing 1 to 2 lb., jagged pieces of metal of all shapes ranging in size from several inches down to the finest dust, and shot and botryoidal shapes ranging in size from 2 or 3 in. down to 0.01 mm. or less in diameter. Slags from furnaces melting scrap brass contain metal in the form of small shot.

Jan 2, 1916

By James M. Henderson, John B. Pfeiffer

The recently completed liquid sulfur dioxide plant at American Smelting and Refining Co.'s Tacoma copper smelter in Washington last April is one step by the firm to meet ambient air quality standards in the vicinities of its three US copper smelters. At a capital cost of $18.5 million, the liquid SO2 plant will work together with an existing sulfuric acid plant to treat all gases generated by the copper converters. Designed to handle up to 45,000 cfm of converter gas utilizing the Dimethylaniline (DMA) process, this plant is expected to recover about 51% of the total smelter input.

Jan 11, 1974

By R. Silverman, H. Blumenthal

It was found that despite the similarity of chemical analyses of different titanium carbides used as base materials for cermets, the physical properties, especially transverse-rupture strengths, of test bars were different. Hence this metallographic study attempts to link physical properties to micro-structures. It is shown that microstructure, grain shape, and grain growth are functions of three interrelated factors: 1—powder production procedure, 2—surface conditioning of the particles, and 3—impurities either contained in the original powder or acquired during ball milling. An explanation is offered for the "coring effect," long observed, but heretofore of unknown origin. The explanation is based on assumption of an oxide film and on chemical analyses which substantiate these findings. TITANIUM carbide has become in recent years a material of great interest in the high temperature field. Consequently, many manufacturers in the United States and Europe are producing titanium carbide for cermet applications as well as for additions to the well known tungsten carbide tools. All present commercial processes of titanium carbide production utilize the chemical reaction of titanium dioxide and carbon to form as nearly as possible stoichiometric Tic. This reaction is carried out in three ways: 1—in a menstruum of molten metal,' 2—in the solid state, either in a protective atmosphere2 or in vacuum;" or 3—in an are-melting operation. In spite of the fact that the pure carbides obtained in these operations are almost identical chemically, the physical properties vary considerably when they are combined with a binder (Ni, Co) to form cermets. This fact led the authors to examine metal-lographically nickel-bonded titanium carbide in order to find the possible reasons for this behavior. Materials and Methods Five different titanium carbides were used in this investigation. They are identified in Table I. The first four materials were used in the as-received condition. Material E, received in lumps, was crushed to —100 mesh and carried through a flotation process in order to bring its graphite content in line with the other products. A Galagher flotation cell was used with pine oil as frothing agent. The chemical analyses of the investigated materials are given in Table 11. The binder used was carbonyl nickel of 9 to 14 microns particle size, supplied by A. D. Mackay. The materials were ball milled at a ball to charge ratio of 6:1 using procedures described under "Experiments and Results." All particle sizes mentioned are averages determined with a Fisher Sub-sieve Sizer. Test bars (lx0.40x0.16 in.) were prepared by 1—hot pressing to 85 to 95 pct of theoretical density at pressures between 1 and 1½ tsi and temperatures from 1600" to 1800°C, 2-—-cold presssing after 3 pct camphor had been added, or 3—wet pressing, both 2 and 3 at pressures between 5 and 10 tsi. All pressed bars were sintered in a vacuum of 105 to 10-6 mm Hg for 2 hr at 1350 °C. Transverse-rupture strengths were determined by breaking on a Baldwin Universal Testing Machine over a 9/16 in. span. Densities were measured by water displacement. The preparation of the specimens for micrographs was done according to Silverman and Doshna Luscz." All magnifications are at X1000. A sodium picrate electrolytic etch was used. Experiments and Results The influence of ball-milling procedure, ball-milling medium, pressing procedure, and sintering procedure on the microstructure of 80/20 — TiC/Ni were investigated. Ball Milling of Materials A, B, and C in a Steel Mill: Figs. 1 and 2 show microstructures of hot-pressed and vacuum-sintered test bars of materials A and B after the respective materials had been ball milled to 2.1 microns particle size in a steel mill and mixed with 20 pct Ni binder. Material A (Fig. 1) shows considerable grain growth. Also evident is a tendency of the carbide grains to coalesce. The density is 98 pct and the low transverse-rupture strength of 111,000 psi is probably caused by many large grains and an unfavorable packing factor. Almost all grains show a slight indication of "coring." Material B (Fig. 2), although showing grain growth, still has many small particles and a better distribution of binder and carbide due to the relative absence of the coalescing tendency. "Coring" can be observed in almost all grains. The high transverse-rupture strength of 179,000 psi and the density of 100 pct are believed to be due to the many small grains completely surrounded by the binder phase. There is also a preference to form spherical grains with material A, while most grains of material B preserve their angular shapes. Material C, of which no picture is given, stays between A and B in every respect. Rounding of some grains can be observed as well as coring, but the latter to a lesser degree than with material B. Its densification is good and the transverse-rupture strength obtained is 142,000 psi. Ball Milling of Materials A, B, C, and E in a WC Mill: When the Tic powders were ball milled to 2 microns particle size in a we mill, then ball-mill mixed with 20 pct Ni binder, hot pressed, and vacuum

Jan 1, 1956

By James Paul

BEGINNING in December, 1933, and continuing to the close of April, 1934, large sums of money were expended in the states of Pennsylvania, Ohio and West Virginia through the conduct of Federal and State Civil Works Administration, financed by the Government as a part of the President's recovery program to furnish employment to mine employees idle as a result of the economic depression. PURPOSE OF THE PROJECT The protection of the public health against the pollution of public water supply by acid mine drainage was the incentive that prompted the request that the sealing of abandoned bituminous coal mines be made a Federal project. A paper before the Central Section of the American Water Works Association, Wheeling, W. Va., on Aug. 24, by E. S. Tisdale, Chief Engineer of the West Virginia Department of Health, tersely says: In October, 1933, the combined experience of the U. S. Bureau of Mines and the U. S. Public Health Service and the States of Pennsylvania, Ohio, West Virginia and Kentucky resulted in a report being filed in Washington, first with the Public Works Administration and later with the Civil Works Administration, where it was favorably acted upon, calling for these governmental agencies under the direction of the U. S. Public Health Service to expend $1,500,000 in a unified effort to seal abandoned coal mines in Pennsylvania, Ohio, West Virginia, Kentucky and six other states farther down along the Ohio river. The report referred to was embodied in a petition that was signed by the chief engineers of the State Departments of Health of the several states contiguous to the drainage area of the Ohio River. The project as established under Federal supervision became interstate with respect to the several states involved, and upon the termination of the Federal project on Feb. 15, it was authorized as a State C.W.A. project, effective Feb. 20, under the supervision of the State Departments of Health and the State C.W.A. Administration, which continued to March 29, and was succeeded by the S.E.R.B. of the R.W.D. from April 2 to April

Jan 1, 1935

By E. F. Kingsbury

ONE of the well-known and important uses of the noble or precious metals has been for electrical contacts. In fact, the elements of this group, comprising gold, silver and. the six platinum metals, have been called "noble" because of their ability to resist heat and corrosion, properties which. were early found to be of importance in good contacts. Of these, platinum and its iridium alloys, palladium, and silver, have been extensively used. In recent years the electrical industry has been responsible for about one-eighth of the total consumption of the platinum metals in the United States. Information is not available as to what part of this one-eighth has been used for contacts but it is certainly an important one. SUBSTITUTES FOR PLATINUM During the past 20 years a considerable number of contact alloys have been proposed in the patent literature largely with the aim of more or less replacing platinum by gold or silver, and some of these alloys are finding increasingly widespread application as the reliability of their performance becomes established. From even the partial data at hand it appears that this substitution by the less precious metals has replaced at least one-half of the amount of platinum that the entire electrical industry would otherwise be consuming at the present time. While the subject is of considerable interest to the metallurgist it is even more so to the electrical engineer and it is surprising that the literature records no systematic and' comprehensive investigation along these lines. Practically all the scattered work on noble metal contacts has centered around platinum as a standard and has had two more or less distinct aims. One of these has been the replacement of platinum by cheaper materials, and the other, the development of materials of superior electrical performance. The merit, of a contact metal has been assumed to be dependent on its infusibility, and since the more precious metals have the higher melting points there has naturally been an association of the two qualities in the sense that the more precious were

Jan 1, 1928

By M. Schwartz, S. K. Nash, R. Zeman

Knoop hardness in the rolling plane and in the longitudinal plane of hot-rolled and cold-rolled sheets of sublimed magnesiu?w was measured as a function of the angle between the long axis of the indenter and the rolling direction. These measurements were correlated with similar data taken on the (0001) and (1010) planes of a single crystal of magnesium where the hardness was measured as a function of the angle between the long axis of the indenter and the [1120] direction. The results were analyzed for compliance with the hypothesis of Daniels and Dunm to account for slip, and with a similar hypothesis to account for twinning. Some hardness anisotropy data are also presented for magnesium-indium and magnesium-lithium solid solution alloys. It is well known that the hardness of a crystalline specimen is different for its different surfaces, and also that the hardness is a function of direction within a single surface. Variations in hardness for single crystals have been found to be much larger than those for polycrystalline materials. Also, materials having low crystal symmetry were found to have a greater anisotropy of hardness than those of high symmetry. 0'Neill1 and Pfeil,2 using a 1-mm Brine11 ball, studied single crystals of aluminum and iron, respectively; and they found a variation of hardness of about 10 pct between readings taken along the principal crystallographic faces. Daniels and Dunn3 found that the Knoop hardness number varied about 25 pct as the long axis of the indenter rotated on the basal plane of a zinc single crystal. The variation on the (1450) plane was about 100 pct, and the average hardness on this plane was about twice that of the basal plane. They also studied the variation of hardness within the (loo), (110), and (111) faces of a single crystal of silicon ferrite and found variations of about 25 pct although the average values for these planes were almost identical. Single crystals of zinc were also studied by Meincke.4 He found that the Vickers hardness numbers varied about 30 pct depending on whether the axis of the indenter was parallel or perpendicular to the (1010) and (1110) planes. Mott and Ford,5 using a Knoop indenter, found a 25 pct variation in hardness on the basal plane of zinc. Crow and Hinsley6 studied heavily cold-rolled bronze, steel, brass, copper, and other metals. They found that the difference in hardness numbers based on the difference in the length of the diagonals of the Vickers indenter was from 5 to 12 pct. Some minerals and synthetic stones show a very large anisotropy of hardness. Robertson and Van Meter7 found the Vickers hardness of arsenopyrite to vary from 633 to 1148 kg per mm2. stern8 using the double-cone method on synthetic corundum found the hardness number to vary from 950 to 2070. And winchell9 reported a variation of hardness number from 184 to 1205 in kyanite. The variation of hardness as a function of direction in a given crystallographic plane in single crystals possesses a periodicity which is related to the symmetry of the lattice. Daniels and Dunn3 found a six-fold periodicity of hardness in the (0001) plane of zinc. They found that the hardness curves of silicon ferrite had a four-fold symmetry in the (100) plane, a two-fold symmetry in the (110) plane, and a six-fold symmetry in the (111) plane. Mott and Ford5 also reported a six-fold symmetry of hardness in the basal plane of zinc. And vacher10 found two-, four-, and six-fold periodicities of hardness in copper on the (110), (100), and (111) planes, respectively. The purpose of this paper is to report the results of an investigation on the anisotropy of hardness as a function of orientation in single crystals of mannes-ium, and samples of rolled magnesium, magnesium-indium, and magnesium-lithium solid solution alloys. The anisotropy of hardness of pure magnesium which had been hot rolled, and then cold rolled various amounts to fracture, was studied by means of Knoop indentation hardness numbers; and the results were correlated with the preferred orientation as determined by quantitative X-ray pole-figure data. A comparison was made of the hardness data obtained from the rolled sheets and those of single crystals of magnesium. In order to obtain a more fundamental understanding of the variation of hardness and of Knoop hardness testing, the data were analyzed by

Jan 1, 1962

By R. E. Zinkham

An investigation has been conducted to compare short transverse and longitudinal fatigue and fracture properties in 4.25-in.-thick, high strength aluminum alloy plates. One plate was produced using standard rolling techniques while the other was pre.forged before rolling. Little difference was shown in fatigue strength of longitudinal specimens taken from mid-thickness of the plate. Howeuer, in the short transverse orientation fatigue strengths at 107 cycles were about 25 and 50 pct less, respectively, for the preforged and standard rolled plate. Differences in fatigue strengths were attributed to grain size and shape as well US orientation of constituents. Fatigue crack propagation rates and fracture toughness were compared at three different stress intensity (K) levels, using a constant compliance, double cantilever, wedge-shaped specimen. In a given plate, comparable fatigue crack Propagation rates were observed in the longitudinal (i9W) and short transverse (TW) orientations. Somezuhat gveater rates were observed in the short transzerse (TR) orientation. The preforged plute gave a lower rate for all three directions. Considerable secondary cracking developed, at times, over portions of the fatigue crack in both plates, particularly at the lower stress intensity levels in the short transverse specimens. Micro structure revealed constituent stringers as possible causes of the crack branching. Fracture toughness was considerably less in both plates in the short transuerse orientation. It is concluded that preforging not only improved directional tensile properties but also the fatigue and fracture properties in general. On occasion, aluminum plates have been milled away for hinges or bolted connections and stressed through the thickness or short transverse direction. Little or no information is available concerning fatigue characteristics or fracture toughness in this loading orientation in aluminum plate, or of the effect of fabrication on these properties. It was the intent of this project to examine, develop, and apply a unique specimen that has been advocated by others to study the fatigue characteristics and fracture toughness of two differently fabricated high strength aluminum plates. Linear elastic fracture mechanics criteria may be applied to the specimen so that the fatigue crack propagation rate and fracture toughness data may be of use for design or inspection applications. Fatigue characteristics are generally measured in the longtudinal or long transverse direction, where fairly large specimens such as center notched panels,' are usually employed. Limitations are evident due to plate thickness, however, in the type and size of specimen that may be tested in the short transverse direction without extensions. Therefore, a specimen that is to be loaded in this direction should, for convenience, be compact. The general type of fatigue crack propagation specimens discussed and employed herein meet this requirement. These specimens are commonly called double cantilever beam specimens and lately "crackline-loaded edge-crack specimens".2 They may vary from a slope of zero (parallel-sides) to a wedge shape, the type employed herein. In general for most specimens the stress intensity KI at the tip of a crack is a function of the load, P and crack length, a. Some varieties of the wedge shaped specimen, however, give essentially a constant stress intensity KI over a considerable range of crack length.' This feature can be a valuable asset in fatigue crack propagation experiments because the stress-intensity can be controlled simply by controlling the load without regard to crack length. MATERIAL AND METHODS Material. A standard rolled (light pass reduction) and a ~reforged and rolled (heavy pass reduction) plate of 7179-T651 material were used for the evaluation. The chemistry, processing history and average tensile properties are shown in Table I. Specimen Selection and Preparation. The specimen selected for the generation of fatigue initiation or S-N data was an axial tension type and is shown in Fig. 1. Specimens were taken from mid-thickness in the longitudinal and short transverse directions from both plates. Specimens were polished with 500 grit paper in a direction parallel to the loading axis. For the fatigue crack propagation tests, the specimen shown in Fig. 2 was used. This is similar to a specimen that has been employed by Mostovoy3 for fracture toughness studies on 7075-T6 aluminum alloy. It also fortuitiously agrees quite well with the dimensions of a specimen for which Srawley and Gross2

Jan 1, 1970

By Robert D. Pehlke, Robert G. Blossey

The solubility of nitrogen in liquid binary and ternary Fe-Ni-Co alloys has been measured by the Sieverts' method between 1550°and 1700°C. Solubility data and standard free energzes and enthalpies of solution for nitrogen in the alloys are presented. Interaction parameters are discussed and presented for binary and ternary alloys. MOST of the studies of nitrogen solubility in liquid metals have been directed toward the dilute alloys of iron. Several of these investigations have included measurements of the nitrogen solubility in Fe-Ni al10s'- and in Fe-Co alloys.435 There has been some work, however, that has extended across the e-i-" and F-CO" binaries. This investigation was undertaken to determine the nitrogen solubility in both binary and ternary alloys of the Fe-Ni-Co system. It was also hoped that the differences between earlier studies might be resolved. EXPERIMENTAL METHOD This investigation was made using a Sieverts' apparatus described previously." The nickel (99.85 pct) and cobalt (99.9 pct) were obtained from Sherritt-Gordon Mines, Ltd., and the iron (99.95 pct) was Fer-rovac-E obtained from Crucible Steel Co. Recrystal-lized alumina crucibles were used throughout the entire investigation with no evidence of crucible-melt reaction. Melt temperatures were measured with an optical pyrometer and the temperature scale calibrated against the melting points of the three pure metals. The emissivity of the melt was assumed to be a linear function of composition for all alloys, as has been shown for Fe-Ni alloys.lZ The emissivity of the pure metals at 1600°C were taken as 0.43 for iron, 0.44 for cobalt, and 0.45 for nickel. Using these emissivities, the trans mis sivity of the system was found to be 0.51 i 0.01. The Sieverts' method was used for this study and followed the procedures outlined previously.l' The individual metals were weighed to give about 100 g of alloy. The alloys were melted in the crucible under a partial pressure of argon. The system was evacuated, and the "hot volume" was measured with argon. To avoid the errors caused by vaporization, the melt was held under vacuum only long enough to ensure that all of the gas in the system had been removed. The influence of any small amount of vaporization on the "hot volume" was shown to be negligible by measuring the "hot volume" after a run. This measurement agreed with that made at the start of the run within the implicit error, 0.2 cc, caused by the limitations in accurately reading the buret. The solubility-pressure relationship was measured in the pure metals and in several alloy compositions throughout the ternary system. These measurements were made by admitting measured amounts of nitrogen to the system, and then determining the equilibrium nitrogen pressure above the melt. This method has the distinct advantage of higher accuracy, particularly at lower pressures, than measurements made by withdrawing gas from the system to reduce the pressure after determining the solubility at 1 atm nitrogen pressure. This latter method has a practical lower limit of about 0.4 atm where an increased error is encountered because the buret must be emptied to permit further measurements at lower pressures. By determining the relation between apparent solubility and pressure, it was possible to make a good estimate of the initial nitrogen content of the metal from the intercept of the solubility curve extrapolated to zero pressure.11 DISCUSSION The solubility data corrected to 1 atm nitrogen pressure are summarized in Table I. The reported solubility has been corrected for the initial nitrogen content of the alloys. The initial nitrogen contents fell between 0.0002 and 0.0010 wt pct, and were lower in the iron and nickel than in the cobalt. Sieverts' law was obeyed in all alloys at pressures up to 1 atm. Examples of this behavior are shown in Fig. 1. The reaction for solution of nitrogen is Taking the standard state as 1 wt pct N in the alloy and the reference state as nitrogen at infinite dilution in the alloy, and noting the adherence to Sieverts' law, K becomes the solubility of nitrogen in the alloy at 1 atm pressure. Thus the solubility data of Table I were used directly to calculate the standard free energy for the solution reaction. These results are also presented in Table I. The enthalpy of solution is also summarized in Table I as calculated from a form of the van't Hoff relation: Iron-Nickel System. The data for the solubility of nitrogen in liquid Fe-Ni binary alloys is presented in Fig. 2 along the with data of aito, Schenck et al.,' and Humbert and 1liott.l' The data for studies of nitrogen solubility in Fe-Ni alloys containing less than 20 pc t i'- are not presented in Fig. 2, although they are in good agreement with the present work. The results of this study are in good agreement with Schenck

Jan 1, 1967

Executive BENJAMIN B. THAYER, .Chairman. JAMES F. KEMP, CHARLES F. RAND, ALBERT R. LEDOUX, JOSEPH W. RICHARDS, Membership KARL EILERS, Chairman. W. R. INGALLS, JOHN H. JANEWAY, Jr., JOHN D. IRVING, SIDNEY J. JENNINGS. Finance CHARLES F. RAND, Chairman. KARL EILERS. W. L. SAUNDERS.

Jan 1, 1917

By W. O. Philbrook, L. D. Kirkbride

IN the normal operation of the iron blast furnace, reduction of the iron oxides is accomplished almost entirely above the tuyeres.' Blast furnace slags usually contain less than 0.5 pct FeO, although higher values may occur with abnormal operation. There is reason to conjecture, however, that incompletely reduced ore may sometimes reach the hearth and enter the slag as a result of heavy slips or, perhaps, even from cores of excessively large lumps of a charge material of poor reducibility. The possibility of reoxidation of iron droplets falling in front of the tuyeres has been considered by several writers. It would be of interest, to know how rapidly iron oxides reaching the slag for any of these reasons could be reduced by reaction with coke or with the high carbon liquid iron in the hearth. In comparison with the hundreds of papers that have appeared on various aspects of the reduction of solid iron oxides by gases and in the presence of several forms of carbon, little work has been published on the reductioin of liquid oxides or slags. Dancey measured rates of reaction of the pure liquid oxides, both FeO and Fe,O,, with molten iron containing about 4.3 pct C. The oxide was dropped into the cup formed in the upper surface of the iron by rotating the crucible and melt. Under these conditions, reduction of either FeO or Fe,O., was completed in less than 10 sec. The present study was concerned with the reduction of FeO from blast furnace-type slags containing less than 5 pct FeO and melted over carbon-saturated iron in stationary graphite crucibles. The results were considerably different from those found by Dancey, as will be discussed later. Although this work is of interest in relation to hearth reactions in the blast furnace, interpretations must be made with caution because the experimental conditions do not duplicate those within a furnace and may not even lead to the same reaction mechanism. The authors were motivated in undertaking this work by an additional interest—the part played by FeO reduction in the mechanism of de-sulphurization of iron by slags under similar experimental conditions. Derge, Philbrook, and Goldman eveloped detailed experimental evidence to support a three-step mechanism for desulphurization like that originally proposed by Holbrook and Joseph' (These reactions are written in molecular form for convenience, but this is not intended to imply the existence of molecules of FeS in the bulk metal phase nor to deny the likelihood of ionic reactions in the slag.) Earlier work by Chang and Goldman" had shown that the overall reaction follows first-order kinetics with respect to sulphur and that the rate of reaction is proportional to the slag-metal interface area, which observations have been confirmed by subsequent work. Later studiese,' have established the influence of al.loying elements on the first and last steps of the reaction. This paper reports a study of step 3 alone, uncomplicated by the simultaneous process of sulphur transfer. Apparatus and Procedure The experiments were made in a conventional high frequency induction furnace powered by a 35 kva Hg spark gap converter. The graphite crucibles used for most of the runs were 14 cm (5.5 in.) deep and 4.8 cm (1.9 in.) ID with 0.75 cm (0.3 in.) wall. An insulating cover with a small opening for withdrawing samples was used to minimize heat loss and infiltration of air into the furnace. The crucible was charged with 300 g of carbon-saturated iron and either 65 or 100 g of prefused slag analyzing 38.0 pct SiO,, 15.4 pct A10 and 47.1 pct CaO. To obtain the cleanest possible interface at the start of the reaction, the metal and slag were brought to temperature together to prevent the rejection of kish graphite that would have been caused by the chilling effect of a large addition of cold slag to carbon-saturated iron. After temperature control had been established, the desired amount of iron oxide was added in the form of a prefused slag of composition 73.6 pct FeO, 7.7 pct AWX and 19.0 pct SiOl. This slag addition was observed to be molten in somewhat less than 1 min, and a very vigorous reaction proceeded for 1 to 2 min after its introduction. Zero time was taken as 2 min after the ferrous silicate slag addition. Slag samples weighing about 0.5 g each were taken periodically by a copper chill sampler." The weight of the initial slag was large relative to the weight of samples removed, so that the slag weight never varied by more than 5 pct during any run. Temperature was measured by a calibrated W/Mo thermocouple immersed in the metal, with a graphite tip cemented over the fused silica protection tube to prevent attack by slag and metal. After some difficulties with uncertain temperatures during the first two runs, the practice adopted to position the thermocouple for reproducible results was to lower the protection tube to touch the bottom of the crucible and then raise it 0.5 cm. The apparent temperature gradient between the bottom of the crucible and the top of the slag was found to be 15°C (27°F). but much of this spread was probably the result of inadequate immersion of the protection tube to off-set conduction losses along the graphite tip when the thermocouple was inserted only into the slag. The temperature of the bath was controlled within 25°C (9°F) during a run.

Jan 1, 1957

By J. L. Workman

The Putnam Coal Mine, at design capacity, will be the third largest underground bituminous coal mine in the world and will feature the world's longest single flight belt conveyor. Construction is now in process; initial mining will commence in early 1969 and design capacity will be reached in 1971. The Putman Coal Mine reserves are located in south-central West Virginia and contain approximately 27,000 acres of prime Pittsburgh No. 8 coal; reserves are sufficient to support a 3.5 million tpy operation for over 30 years. The mine portal area is located some six miles inland from the Kanawha River. The river loading facility is located approximately 156 miles by way of river from the market.

Jan 1, 1969

By Fred P. Dewey

Early last March Mr. Jerome Coldren, an old miner add prospector, undertook a prospecting tour through the western part of Kansas, and discovered a very peculiar bed of rock, which yielded a white metal on fusion with soda. Mr. W. D. Church, city chemist at Topeka, examined the metal and found it to contain nickel. This discovery created much excitement, and was at first doubted. Many samples of the material, from a range of twenty miles, were sent to the Smithsonian Institution for examination ; and in every instance a qualitative test showed the presence of nickel, although the amount appeared to vary greatly. The ore is quite different from any other nickel-ore. It consists of a quartzose conglomerate from bean-size down, with much decomposed material between the pebbles, and the whole cemented by a more or less manganiferous limonite. In the qualitative tests, the nickel appeared to vary with the manganese. In all the tests, simple treatment with HCI dissolved a great deal of AI2O3. The principal deposit is near the top of a small hill on the divide between Smoky Hill river and Butte creek. The surface-rock is the conglomerate, and, at varying distances, stains of the limonite appear and gradually increase ; so that the ore is simply the lower portion of a bed of conglomerate which has been heavily charged with the manganiferous limonite. Below the conglomerate is a layer of selenite; below this, a soft sandstone, containing well-preserved fossils, and below the sandstone, a shale. From 2 to 6 per cent. of nickel in selected samples has been reported by different chemists; but the following two analyses on large samples show the average composition of the material:

Jan 1, 1889

By Louise B. Freeman

Kentucky for the first time in its oil history passed the 10 million barrel mark. Of the total 10,019,641 bbl., 8,262,516 bbl. were produced in Western Kentucky, and Union County surpassed all others, with 4,056,142 bbl., or 40 percent of all the production for the state. There were 930 wells known to have been drilled during the year; 510 in Western Kentucky and 221 in the gas-producing area of Eastern Kentucky.

Jan 1, 1946

By I. S. Servi, N. F. Graves

THE etch-pit technique has long been used to reveal low-angle boundaries and, in general, the distribution of dislocations in high-purity metals. Often this technique is amenable to quantitative computations,' but generally is affected by some degree of uncertainty because etch pits can be nucleated not only by dislocations, but also by inclusions and surface imperfections. In the case of high-purity zinc, Gilman' reported that etch pits were produced only after adding 0.1 atomic per cent of cadmium to the crystals and aging at a proper temperature. In the course of a study of low-angle boundary behavior in zinc crystals, etch pits were produced in 99.999 pct zinc without resorting to intentional contamination, by etching in a 50:50 HNO3H2O solution. The technique consists of etching until the heat of reaction brings the solution to a boil, and in displacing the etchant rapidly with a stream of cold water, thus avoiding staining. The undesirable features of this technique are the heating effect and the removal of a considerable amount of material. A high polish is obtained if staining is controlled properly; therefore, the etch pits appear very clearly and with excellent contrast when observed under dark field illumination. This is especially helpful for cursory examinations at low magnifications. Several observations were made on zinc crystals of square cross section, having one face parallel to the basal plane and one edge parallel to a slip direction, Fig. l(a). When such a crystal was bent about 2" over a glass die and annealed at 390°C, a sharp boundary was formed only in the inner portion of the crystal. Near the two prismatic faces, perpendicular to the basal plane, the boundary was always branched into many lower-angle boundaries, Fig. 1(b). Attempts to move the main boundary by applying a shear stress to the specimen invariably resulted in curving the boundary, the branched ends remaining pinned in their original location, Fig. 1 (c). The prismatic face, when etched as indicated in the foregoing, revealed the existence of numerous (sometimes up to 30) fine boundaries, nearly parallel to each other. Pre-existing lineage boundaries, generally parallel to the direction of growth, were barriers to the formation of polygonization boundaries and interrupted the continuity of the substructure, Fig. 2. Twin

Jan 1, 1959

By G. L. F. Powell, L. M. Hogan

Samples of silver and Ag-O alloy, 0.12 wl pet, have been undercooled to a maximum of 250°C by melting in a slag of commercial soda-lime glass. Grain refinement occurred in undercooled silver samples whet the degree of undercooling exceeded a critical value which varied from 153° to 175°C, depending on the melting conditions. In under cooled Ag-0 samples, the grain structure was fine and equiaxed at degrees of undercooling larger than 50oC. The grain refinement in both silver and Ag-0 alloy samples was the result of recrystallization during or immediately following freezing. When the oxygen content was increased, the degree of undercooling at which recrys-tallization occurred decreased. INVESTIGATIONS of the grain structure of strongly undercooled melts of nickel and cobalt1-4 have revealed a change in room-temperature grain size as a function of undercooling. At large degrees of undercooling the grain size was fine, but samples undercooled by smaller amounts exhibited a much coarser grain structure. The reported undercooling at which this grain size transition occurred in nickel varied between 140° and 175'C undercooling. Walker1 attributed this grain size change to an enhanced nuclea-tion rate. Cavitation at a melt-solid interface was con sidered to generate a high-pressure wave. This, in turn, produced nucleation in the liquid as a result of an elevated freezing point increasing the undercooling in the melt. A similar grain size transition was observed in undercooled silver between 133° and 153°C undercooling.5 The grain size transition in undercooled silver was found to be dependent on oxygen con tent. More recently, the authors5 showed that a simila transition occurred in an undercooled Cu-O alloy, =0.08 pet, but not in oxygen-free copper undercooled more than 200°C. The transition was attributed to recrystallization of the solidified grains after freezing; the greater the degree of undercooling, the more complete the recrystallization. In view of this effect of oxygen content on grain size transition, additional undercooling experiments were carried out with silver. This paper reports the results of these studies on silver and Ag-O alloys undercooled more than 50°C EXPERIMENTAL 1) Materials. The silver was supplied by Matthey Garrett Pty., Ltd., as fine granulate, silver mini' mum 99.9 pet, and contained the trace impurities shown in Table I. The silver originated from two different refineries resulting in the difference in impurity content shown in Table I. However, the variation in composition had no discernible effect on the undercooling behavior. Samples of the silver were melted in an open-ended, vertical, cylindrical resistance furnace, wound with Kantha] wire, the temperature of which was adjusted by means of a variable transformer, 2) Melting and Undercooling. Bulk samples of silver were undercooled by preoxidation and removal of oxidized impurities in a glass slag, as previously described,5 but special precautions were necessary to allow comparison between oxygen-free silver and a Ag-O alloy. Samples free of oxygen were prepared by first melting weights of granulate varying from 200 to 400 g in clean vitreous silica crucibles in air for approximately 15 min. A sample was frozen and a complete glass cover formed over the top surface by adding granulated glass rod. The sample was then melted and frozen several times until no oxygen bubbles appeared in the glass slag. Subsequent thermal analysis indicated that the oxygen content was negligible. The glass acted as an efficient barrier to absorption of oxygen from the air. Ag-O alloys were prepared by melting silver in silica crucibles with only a partial cover of glass, so that the top surface of the melt was in contact with air. The silver was held molten in air for several hours at 1000° to 1050°C, in the expectation that the oxygen in solution would reach equilibrium with atmospheric oxygen. At T - 1000°C the equilibrium oxygen content was calculated as 0.12 wt pet O, using Sieverts law and Eq, [l], derived by Mizikar et a!.7 from the data of Sieverts and Hagenacker8 for 1 atm of oxygen:

Jan 1, 1970

By J. E. Hilliard

Various methods are given for estimating the number per unit volume and average size of convex particles from measurements on a projection through a slice of the structure. The determination of the size distribution is considered specifically for spherical particles. The results are applicable to any type of transmission microscopy and also to the correction of measurements made by reflected light on semitransparent materials. WITH the advent of electron transmission microscopy, the metallurgist is confronted with the problem of relating a projected image to the three-dimensional properties of the structure. This paper deals with the estimation of the number per unit volume and size of particles dispersed in a matrix. The case of convex particles will first be treated (the results will be applicable as approximations to particles of more general shape) and then spherical particles will be considered specifically. The latter represent a special case frequently encountered in practice and one which is also amenable to a calculation of the effect of overlap on the observed particle-size distribution. Although the present treatment was prompted by the needs of the electron microscopist, the results are applicable to transmission studies with any type of radiation. In addition, they can be used in the analysis of semitransparent materials by reflected light, the depth of light penetration corresponding to the thickness of the slice or section used in the transmission studies. 1) CONVEX PARTICLES 1.1) General Expression for N,. We will suppose that a "center" (such as the center of mass) is assigned to each particle. The convention used for defining the center is immaterial providing it does not depend on the orientation or location of the particle. Consider a slice through the structure having a pair of parallel faces a distance t apart. It will be assumed that the slice is randomly located with respect to its perpendicular distance from some fixed point, but it is not necessary to assume that its orientation is random. Our problem is to deduce the relationship between the number of par- ticle images seen on an orthogonal projection through the slice with the number, Nv, of particles per unit volume in the original structure.* *Symbols are listed in the Table. The expected number of particles with centers lying within the slice is Nvt per unit area. In addition, there will be elements in the slice contributed by particles whose centers lie without. The number of such elements will be the same as the number of intersections occurring on a two-dimensional plane through the structure; namely N~K, where K is the mean distance, Fig. 1, between tangent planes to a particle averaged over all particles, i.e., Where Ni is the number of particles of class i having the same shape and size, and pi (4, 8) is the probability that an i particle will have a given orientation with respect to the slice. If the particles are randomly oriented, then K is independent of the orientation of the slice and equal to the mean cali-per diameter. The total number of particle elements in the slice is therefore Nv(t + K) per unit area, but fewer will be seen as separate images on the projection plane because of overlap. If MA is the number of elements "lost" by overlap, the number of images per unit area will be NA = Nv(t + K) -MA 121 MA is a function of the slice thickness and must vanish at t = 0. As t increases, NA at first increases, reaches a maximum, and thereafter decreases as the overlap term MA becomes predomi-

Jan 1, 1962

By C. Altstetter

THE work herein reported is restricted to the carbides which occur in quenched and tempered AISI 43XX steels with carbon contents up to 0.40 pct and silicon additions of up to 3 pct. In view of the instability and extremely small size of the carbides formed at low tempering temperatures, the technique for successfully preparing specimens for X-ray diffraction will be outlined. The alloys listed in Table I were obtained through the courtesy of the United States Steel Corp. in the form of 1/2-in. rounds forged from 100 lb. induction furnace heats (except for 4337 which was a commercial heat). The stock was normalized and then swaged and drawn to 15 mil wire with anneals at 1200F between passes. The wire was austenitized for 45 min in evacuated vycor capsules and quenched into iced brine with simultaneous smashing of the capsule. Tempering was done in air with a water quench after tempering. The carbides were extracted in a simple cell using a solution of 1M KC1 and 0.5 pct citric acid with an initial current density of 0.1 amp per sq cm. One end of a short length of wire was immersed in the solution, and the current at constant voltage was noted as a function of time. After about an hour the current dropped sharply because of the decrease in specimen cross-section. At this point it was found that the dissolution could be stopped and that the very fine wire which then resulted was just large enough to permit handling of the extracted precipitate still clinging to it, yet so small that it diffracted and absorbed only a negligible amount of the X-radiation. This rod of residue with a convenient handle of undissolved wire was rinsed in distilled water. alcohol, and acetone. Then it was dipped in a thin solution of cellulose-acetate cement and dried in vacuum. The resulting specimen was straight, uniform in density, easily handled, but most important, was completely sealed and never exposed to air. Furthermore, the residue had never been subjected to strong acids or rough handling such as in the extraction-replica technique or in the complete extraction to a powdered residue. It was found that improperly coated specimens were pyrophoric, turning to oxide with a dull red glow as they were exposed to air and yielding patterns of Fe2O3 and Fe3O4. The steels containing 3 pct Si were especially difficult to prepare for this reason. The specimens were put in a 57 mm Straumanis camera with double pinholes or slits and irradiated with filtered-chromium radiation. Readable patterns were obtained in less than an hour. A preliminary finding of some note was that for both tempered and as-quenched specimens of steels 4337 and 4337 (1.5 Si). M23C6 patterns were found along with the patterns of other constituents of the residues. This result was somewhat surprising in that previous investigators had reported that this carbide did not appear in a 0.38 pct C, 0.48 pct Mo steel1 or in chromium steels of less than about 10 pct Cr.2 Although the total amount of carbide-forming alloying elements is less than 2 pct, due to their mutual interaction and the action of the plastic deformation in promoting equilibrium, this carbide was able to form even in the steel containing 1.5 pct Si. M23C6 was not detected in the 4337 (3.0 Si) steel and the lower-carbon steels were not investigated in this condition. It is very likely then that the steels studied herein underwent a fourth stage of tempering during the anneals at 1200°F. This result has significance in that even a small amount of undissolved M23C6 in a low-carbon, low-alloy steel would exert a large effect on its hardenability. Its presence would also influence the mechanical properties by decreasing the carbon content of the matrix. Annealing in vacuum for 1 to 4 hr in the austenite field removed all traces of MZ3C+ The results on carbide precipitation during tempering, summarized in Table I, are in agreement with those of Klingler et al.3 for the higher carbon steels. For the AISI 4337 steels it is noteworthy that in the steels with added silicon the E carbide persists to longer times and higher temperatures and that silicon delays the formation of cementite. The results for the lowzr-carbon steels parallel those of the higher-carbon grade. The appearance of E carbide in the AISI 4315 is significant. There is considerable disagreem-nt in the literature as to whether this carbide forms in the tempering of steels containing less than about 0.2 pct C. Following the detection of E carbide in a 0.18 pct C plain-carbon steel,4 its occurrence in a steel containing chromium and molybdenum should be expected. The fact that the low-carbon steels have the same carbide-precipitation sequence as the high-carbon steels has bearing on the larger problem of the exact tempering reactions in all steels. Following the suggestion of Roberts et al.,' the first stage has been generally assumed to result in a metastable equilibrium of c carbide and martensite of about 0.25 pct C. From this it was concluded that a steel having less than 0.25 pct C should then be under-saturated with respect to c carbide and should not precipitate this carbide upon tempering. In view of the experimental findings of c carbide in steels hav-

Jan 1, 1962