Search Documents

By R. E. Cech

Particles -3 to 30 µ diam of a 29.5 pet Ni, 70.5 pet Fe alloy after being melted and solidified while falling through a hydrogen atmosphere were found to contain a distortion-free body-centered-cubic phase. In most particles, the amount of body-centered-cubic phase approaches or equals 100 pet. It was shown by a series of experiments that this phase forms directly from the liquid. It is pointed out that a mechanism previously suggested in recent papers on the theory of the liquid-solid transformation can account for the solidification of body-centered-cubic phase in a temperature range where face-centered-cubic is the stable phase. IN the course of an operation to produce powders for a study of the martensitic transformation in Fe-Ni alloys, an unexpected phenomenon was observed. Powders of a 29.5 pet Ni alloy, which has a subzero M, temperature, were found to contain considerable amounts of a body-centered-cubic phase at room temperature. The experiments to be described were designed to elucidate the mode of formation of this unexpected phase. Experiments and Discussion An alloy containing 29.5 wt pet Ni, balance iron, was vacuum melted from high purity electrolytic iron and carbonyl nickel shot and solidified in the crucible. The metal was converted to oxide, ground to 100 pet <37µ, pressed to a cake, and homogenized 20 hr at 1350°C. To insure homogeneity the grinding, pressing, and homogenizing heat treatment was repeated a second time. The oxide was then ground to 100 pct <37µ and hydrogen reduced at 500°C. The reduced powder was given a spheroidizing treatment to produce spherical cast particles. The treatment consisted of dispersing the particles in hydrogen and allowing them to drop through a vertical hydrogen furnace set to a temperature higher than the liquidus of the alloy. This operation, commonly known as shotting, has been described more fully elsewhere.&apos; The powder produced by this method was found to contain approximately equal parts of body-centered-cubic and face-centered-cubic phases. A magnetic separation technique, previously described,&apos; was applied, and it was found that particles were either completely face-centered-cubic or nearly completely body-centered-cubic. The microstruc-

Jan 1, 1957

By P. D. Rao, H. B. Charmbury, D. R. Mitchell

As a result of a changing market pattern for anthracite, there is now an increasing demand for steam size and a decreasing demand for domestic sizes. To help the producer meet this new demand, the authors present the technical aspects of the problem of crushing domestic sizes to steam fineness and size. The market pattern for anthracite coal has changed considerably in recent years. The demand for domestic sizes has been gradually decreasing and the demand for the steam sizes has been increasing. The companies however aim for a maximum production of domestic sizes, since these sizes command premium prices. To meet the market demands, particularly in certain periods of the year, further size reduction of the coarse clean coal is necessary. The present practice of multistage crushing in toothed rolls leads to complicated flow arrangements and is high in cost. Data presented herein indicate that crushers with high reduction ratios could be used with a resulting simplification of crushing flows and an appreciable reduction of capital and operating costs. The different types of crushing equipment investigated included the rotary-type breaker, the jaw crusher, the impactor-type crusher, and the Aerofall mill. CURRENT PRACTICE The standard sizes of anthracite are presented in Table I and market specifications require that any given size be maintained with only a limited amount of oversize and undersize material. The 1958 prices of the various sizes also are presented, so it may be seen that size reduction is only performed when dictated by market demands. At the present time the general practice of crushing anthracite consists of removing the top size and crushing it in a toothed double roll crusher to the next largest size. Consequently, to reduce the domestic egg, stove, and nut sizes to steam sizes of pea, buck, rice, and barley, the original material must be screened to produce the three top sizes and each size must be crushed in three separate rolls to the next largest size. Each crushed product must then be rescreened to remove the oversize for re crush ing. Thus a typical operation would consist of scalping the egg size from a mixture, crushing it to stove size, and rescreening the product. This same cycle would be repeated for the stove and nut sizes requiring three screens and three crushers as well as conveying equipment to handle the crushed products. This results in an expensive series of operations to make a product which sells for a lower price. If the three top sizes are crushed in one operation to the smaller sizes then the yield of steam sizes is low and the production of Nos. 4 and 5 sizes is large. These sizes sell for lower prices than the steam sizes. A typical operation is presented in Fig. 1. From the figure it may be seen that the original cleaned anthracite contains 67.4 pet domestic sizes, 26.4 pct steam sizes, and 6.2 pct fines. After multistage crushing of the domestic to steam sizes the composition of the product is 0.6 pct domestic sizes, 89.6 pct steam sizes, and 9.8 pct fines. From a technical standpoint these results are reasonable but the handling and crushing costs are

Jan 1, 1961

By A. E. Nehrenberg

R. A. Schmucker, Jr.—The writer wishes to point out that an acicular growth of austenite, similar to that described in the author&apos;s paper, was recently observed in an alloy steel of only 0.06 C content. This steel, which represents an 0.07 max C, 1.35 Cr, 0.55 Ni, 0.20 Mo analysis, combines the characteristics of minimum hardness in the annealed condition with maximum hardenability and is therefore suited primarily for cold-hobbing applications. The acicular austenite formation in this steel was observed accidentally during a determination of its Ac1 temperature. The samples used in this investigation represented as-forged bar stock which had been given a preliminary temper at 1300°F. The critical (Ac1) temperature was finally established at 1400 °F. Fig. 15 represents the microstructure of the sample which had been heated at 1450°F for ½ hr, water quenched, and tempered at 600°F for ½ hr (for the purpose of darkening the martensite). It will be observed from the distribution of the darkened areas of martensite that the parent austenite grains formed at 1450°F had grown in an acicular manner and still occupied only a small percentage of the total area. The remainder of the area contains the original equiaxed ferrite grains in which new austenite had as yet scarcely formed. However, the tiny isolated martensitic patches at several points where three or more ferrite grains intersect indicate that small austenite grains had formed and started to grow in an apparently equiaxed fashion. Fig. 16 represents the prior microstructure of an original sample in the as-forged and tempered condition, before it was heated -above the critical temperature. It is probable that there are two kinds of ferrite in this structure: (1) The equiaxed proeutectoid ferrite grains which separated from the austenite when the steel was cooled from the forging temperature, and (2) the acicular ferrite associated with the aggregate of fine carbide which is represented by the patches of

Jan 1, 1951

By R. M. Asimow, J. J. Svitak

Tile crilical resoll,r,d shear stress, CRSS, for slip of slow1y cooled Ag-All single crystals was measured at 201K. Tlze importance of short-range order and Suzuki sogregalion was inrestigated by deter~rlining llze ciic.cl of quenching on the CRSS. Thr obserz.ed rfrtenching effects were generally small and indicate that short-range ordcr and Slczuki srgregation do no1 account for n significant portion of the solid-solution strengthening in this system. However, all alloys slzozcwi yield drops ulhich rilere heat- lreat nrenl-sensiline THERE have been a number of mechanisms proposed to explain alloy strengthening in the Ag-Au system. The effectiveness of some of the proposed mechanisms, especially those that depend on Suzuki segregation1" or on short-range order,2-6 SRO? should be strongly dependent on heat treatment. Since internal friction investigations in this system indicate that there is stress-induced order,&apos; we must also consider the possibility of local atomic rearrangement or short-range ordering in the stress field of a dislocation. There is not complete agreement whether these mechanisms should be most effective in raising the flow stress, in causing yield drops. or some combination of these two effects. This work was undertaken to determine the effects in the Ag-Au system of mechanisms that depend on segregation or order by using known but drastically different cooling rates following a high-temperature treatment. By comparing the critical resolved shear stress, CRSS, for slip measured after a very slow cool and again after a fast cool (quench) of the same crystal, it is possible to determine the effect of cooling rate on CRSS* and on yield drops. The single-crystal CRSS was determined at several compositions because there has been no data published across the phase field since the publication of room-temperature flow stress by Sachs and Weerts.&apos; EXPERIMENTAL PROCEDURE Starting with materials of 99.999 pct purity, single-crystal specimens of random orientation 1.25 mm square by 4 cm long were prepared with 0, 10, 14, 25, 30. 50, 70. 75. 80, 90. and 100 at. pct Au. Crystals were grown in an inert atmosphere using a modified Bridgman technique with a growth rate of 1.5 cm per hr in a gradient of 3°C per cm. To obtain a maximum practical degree of SRO, the crystals were cooled at a rate of 275&apos;C per hr to about 310°C and then cooled at 6°C per hr to approximately 200°C. Specimens were tested in tension immersed in an alcohol bath at -72°C (201°K) at a strain rate > = 0.003 mm"1 to determine the CRSS (7). The activation volume of several crystals was determined from the flow stress increment (72 - T1) for a tenfold increase in strain rate. The total shear strain varied from 0.05 to 2.3 pct but was generally less than 0.4 pct. After testing, each crystal was then held at 500°C for 10 min, quenched into brine at -35°C and. after storage at -71°C for 1 day, retested in tension using a procedure identical to that of the first test. The quenching apparatus, see Fig. 1, was designed to enable accurate temperature control and rapid quenching while preventing specimen contamination and accidental deformation. Test data from a specimen with a fine thermocouple spot-welded to it indicated a cooling rate of 104C per sec. The relatively low heat-treatment temperature was chosen to minimize quenching defects caused by a large vacancy

Jan 1, 1970

By N. J. Grant, B. C. Giessen, R. Koch

The system Nh-Ir was investigated over the complete concentration range by metallography and X-my techniques, using forty one alloys. The solubility limits of terminal and intermediate phases and the solidus temperatures were determined. Five intermediate phases were found: a Nb3Ir, cubic, Cr3O type; tetragonal, ofecr thorhomhic, isostruc-turn1 with (ta-Rh); and a Nhlr3. cubic, AuCu, type. a Nb3lr and a Nbfr3 melt congruently; three eutectic and three pentectic reactions occur. The phase diagram of the Nb-Ir system had not been fully treated in the literature; only surveys of intermediate phases were found.1"5 In this study, the details of the phase boundaries were investigated as well as the crystallography of the intermediate phases. EXPERIMENTAL METHODS The experimental procedures such as arc melting of powder compacts, heat treatments, solidus measurements, X-ray, and metallographic observation were identical with those used in the work on the Nb-Rh phase diagram.&apos; They will therefore not be repeated here except where the conditions differed. The purity of the niobium powder was as stated in Ref. 6; the iridium powder of 99.9+ pct purity from J. Bishop and Co., Malvern, Penn., did not contain impurities exceeding 100 ppm, except rhodium (200 ppm). The melting points and vapor pressures of both elements are very similar. This fact contributed to a very small weight loss on melting and facilitated preparation of homogeneous alloys. As shown in Ref. 6 for Nb-Rh, no oxygen pick-up exceeding 200 ppm had to be considered; this was regarded as valid also for Nb-Ir. A total of forty one alloys were used in the determination of the phase diagram; their concentrations are shown in Fig. l, which presents the phase diagram. The concentration limits as determined by the weight-loss method averaged <0.2 at. pct, and never exceeded 0.5 at. pct. Heat treatments were carried out as described in Ref. 6. Depending on the concentration, only tantalum, tungsten, or iridium containers were employed, avoiding oxide crucibles altogether. Alloys from 0 to 25 and from 65 to 100 at. pct Ir were homogenized at 2095°C for 15 hr, intermediate compositions from 25 to 65 at. pct Ir for 65 hr at 1780°C. A typical annealing-time schedule is presented in Table I. Solidus points were measured as described in Ref. 6 with the modification that samples rich in niobium were held between pieces of tantalum foil and samples of high iridium concentrations were held between rhenium platelets or in iridium wire. After each run it was ascertained metallographically that no reaction with the holder had occurred. Rhenium was selected as holder material after it had been shown in separate tests that the melting points of Re-Ir alloys rise continuously from 2440°C. Metallographic examination was carried out as described in Ref. 6, and the same procedure and etchants were used successfully. While metallographic discrimination between a Nb3lr and o was easily possible, X-ray diffraction was necessary to separate al and ct2. X-ray powder patterns were taken and evaluated as for Nb-Rh6 yielding the error limits indicated in Table 111, to be introduced later. For the determination of the invariant reactions and phase boundaries, the same techniques as for Nb-Rh6 applied. The general accuracy of invariant concentrations is regarded as somewhat higher than for Nb-Rh due to the small slope of most solvus lines.

Jan 1, 1964

By C. P. Miller

In order to determine the usefulness of geochemical and biogeochemical prospecting for nickel, ten localities representing several types of nickel occurrences were selected as sites from which to collect plant and soil samples. This report covers the investigations in two of the areas. After a brief geologic description of the areas, the author presents details of the experimental tests and resulting data. Conclusions drawn from the studies led to several general guides for further prospecting. In a study of the usefulness of geochemical and biogeochemical prospecting for nickel made about three years ago, approximately ten localities, representing several different types of nickel occurrences, were sampled and about 1500 samples of plant and soil were collected. This report will cover briefly the data and results for two areas, and a summary of guides for prospecting. DESCRIPTION OF AREAS SAMPLED One locality is the Red Flats nickel prospect in Curry County, Ore., about six miles southeast of Goldbeach, and the other is the Little Rocky Creek prospect in Stillwater County, southcentral Montana, just southeast of the Benbow chromite mine. The Oregon area is a lateritic-type nickel deposit formed on a nickel-rich serpentinite peridotite complex, similar to the Josephine intrusion in southwestern Oregon. The Montana area is a nickel prospect in norite, peridotite, and related rocks of the Stillwater igneous complex. The Stillwater complex is a series of layered basic and ultrabasic rocks, with a layer of norite-gabbro at the base and a series of peridotites and gabbros above. The nickel in the Oregon deposit occurs in both the peridotite and the overlying soil. A deep lateritic soil is developed locally on the peridotite and serpentinite and constitutes the ore. The average nickel content of the lateritic soil is less than 1 pct, whereas the nickel content of the weathered peridotite is about 1 to 1.5 pct. The nickel occurs as garnierite (Mg, Fe, Ni, Mn)3 (OH)4 (SiA1)2O5 in the soil and in the olivine and pyroxene in the peridotite where it probably substitutes for Fe2+ or Mg2+ in the silicate lattices. Nickel is found in three distinct ways in the Still-water rocks: 1) it is in the olivine and pyroxene minerals in norite, harzburgite, etc.; 2) it occurs as widely disseminated grains of pentlandite-pyr-rhotite, which tend to be concentrated in the lower norite band; and 3) it occurs as discrete bodies of pentlandite-pyrrhotite and chalcopyrite which are localized in the norite zone, close to the contact with the underlying rocks. The nickel content of the norite is probably less than 1 pct, and the nickel content of the pods and lenses within the norite is about 1 pct. PROSPECTING APPROACH Although the areas are different geologically, the approach in prospecting them is fundamentally the same. The procedure is twofold: 1) a rapid reconnaissance survey to outline an area of high nickel content, and 2) a more detailed survey to outline zones of possible ore grade within the area of high nickel. The possible ore at Red Flats is concentrated in the lateritic soil, whereas at Little Rocky Creek it is in the sulfide pods. Both types are surrounded by an area of relatively high nickel content. CHEMICAL ANALYSIS Chemical analyses of nickel were made by a di-methylglyoxime colorimetric test, similar to the standard test for nickel, utilizing concentrated sul-furic acid for extraction. The lower limit of detection for nickel in soil by the method used was about 10 ppm and for nickel in plants about 5 ppm. The relative deviation was about 25 pct. SOIL PROSPECTING General Statements: A summary of the approximate average parts per million of nickel in soil, as compiled from the literature and from my study, is given in Table I. Selected references are given at the end of the paper. Few of the investigators reported the type of extraction or analysis, so the data given may not be strictly comparable to mine, which were made with a sulfuric acid extraction. Any nickel concentration greater than these average values might be considered anomalous, although each area must be studied in relation to the surrounding rocks. Method of Soil Sampling: The soil samples were taken in a zone from 1 in. to 1 ft below the humus layer, and within a 15-ft radius around a station.

Jan 1, 1961

By K. A. Johnson, F. H. Ellinger, C. C. Land

The Pu-In phase diagram has been determined by thevmal, filtvation, micrographic, and X-ray diffraction methods. This alloy system is characterized by 1) limited solubility of indium (-2 at. pet) in 6 and e plutonium, 2) one eutectic, and 3) fizte intermediate phases. Of the latter, PuIn and PuIn3 melt con-gruently, and Pu31n, Pu31n5, and the high-temperatuve 7 solid solution are formed peritectically. The n phase decomposes eutectoidally into Pu3In and PuIn at 865°C. Although the 6 phase can readily be retained to room temperature, it is not thermo-dynamically stable below 300°C. The Pu-In system has been investigated at Los Alamos as part of a study of the alloys of plutonium with the group 111-B elements. Constitutional studies of the Pu-A1 and Pu-Ga systems have been reported earlier.&apos;9&apos; To date, published information on the constitution of Pu-In alloys covers only the identification of the intermediate phases Pu3In and PuIn3.3,4 EXPERIMENTAL The alloys were prepared from five different lots of plutonium and three different lots of indium. The principal impurities in the plutonium differed from lot to lot within the following limits (in ppm): iron, 30 to 80; nickel, 30 to 60; aluminum, 15 to 30; silicon, 20 to 145: thorium, 50 to 300; carbon, 75 to 335; and oxygen, 20 to 135. Spectroanalysis of the indium showed that two of the lots were 99.9 wt pct pure, and the third was 99.98 wt pct pure. The alloys, in the form of about 5-g buttons, were prepared by arc melting in conventional equipment. The components for each alloy were weighed to the nearest 0.1 mg. In most instances the weight losses during melting were negligible; therefore confirmatory chemical analyses were usually not made. A few results are given in Table I. Density measurements of the arc-cast buttons were made by the liquid displacement of bromoben-zene. Heat treating was done in muffle furnaces controlled to +2°C. The alloy buttons were wrapped in tantalum foil before being enclosed in evacuated clear silica capsules. As a precaution against breakage, each capsule was in turn placed in a silica tube closed with a refractory wool plug prior to being charged into the furnace. For a moderately fast quench of the alloys, the outer protection tubes containing the capsules were plunged into cold water. Differential thermal analyses (DTA) in racuo were performed at heating and cooling rates of about 1.5°C per min. Tantalum crucibles having inverted thermocouple wells were used for most of the analyses. It was found micrographically, however, that the liquid alloys containing more than about 35 at. pct In reacted with the tantalum, resulting in contamination of the surface of the alloy. A search for a more satisfactory crucible material was not successful: tungsten and yttria behaved comparably to tantalum; thoria, vitrified magnesia, and vitrified alumina severely contaminated the alloys. So as to minimize the contamination by the crucible mater-

Jan 1, 1965

By Smith, George Otis

THE matter that I have on my mind this evening is engineering&apos;s need of an open forum. Our fathers of three centuries ago were pro-testanta for freedom of speech and thought in matters religious; later, our fathers were revolutionists for freedom of speech in matters political; until today freedom of speech has become so universal throughout the land that even in the sanctuary of our homes, at times, we have to turn off the loud-speaker. Talk is not always a condition of progress, but light is everywhere necessary to growth, whether the growing thing is a blade of grass, a baby chick, or a young idea, and we must regret anything that tends to shut out the light from the operations of business and industry. Of course, I realize there is little that is novel in what I am saying. Indeed, I have found that Dr. James Douglas-a name we love to honor in our Institute-as long ago as 1907, gave an address at the Toronto meeting that any of us would be proud to be author of twenty-one years after. Dr. Douglas at that time spoke on secrecy in the arts and the text then taken by this leader in metallurgical technique and in the constructive management of big business was "the dangerous temptation to adopt secretive methods by very large corporations." In both thought and language Dr. Douglas was direct and vigorous and he needs no internreter. He advocated the wide open door for ideas on two counts: advancement of technical knowledge and education of public opinion. A few sentences will serve not only to prove the vision of James Douglas, but also, I hope, tempt you to hunt up his address in the Institute&apos;s TRANSACTIONS, and thus get his whole thought first hand.

Jan 1, 1928

By Mason K. Banks

A process has been developed which produces spodumene concentrates assaying 6.0 pct Li2O and 0.45 pct Fe2O3, with 70 to 75 pct recovery of spodumene. Two flotation separations are required: the simultaneous removal of mica, feldspar, and quartz as a froth product using a cationic collector, and the subsequent removal of iron-bearing minerals as a froth product while spodumene is depressed as a tailing. SINCE the close of World War II there have been numerous developments resulting in the increased use of lithium by industry. Notable among these has been the development of an industrial lubricant, based on lithium stearate, which is fluid at low temperatures, stable at high temperature, and insoluble in water. A new bleaching agent, lithium hypo-chlorite, has also been developed recently.&apos; Other well-known uses are listed below: 1—Lithium oxide in ceramics reduces firing time, lowers melting temperatures, lowers thermal expansion, raises refractive index, and improves chemical resistivity. 2—Lithium carbonate and lithium strontium nitrate are used in pyrotechnics for their brilliant red color.&apos; 3—Lithium chlorides and fluorides are used as fluxes for welding aluminum and magnesium.&apos; 4—The affinity of lithium for nitrogen is the basis for a process used in purifying helium." 5— Lithium chlorides and bromides are used in air conditioning for their powers to absorb organic amines, ammonia, and smoke.6-—Lithium hydride has been used as a source of hydrogen to inflate life rafts and balloons used by the Air Forces and Navy.&apos; 7— Lithium metal and lithium hydride are useful in the atomic energy program in connection with the production of the isotopes of hydrogen." During the 1942-45 period of World War 11, Solvay Process Co. operated a flotation plant with a daily capacity of 300 tons of ore for the production of spodumene concentrate near Kings Mountain, North Carolina. The operation was shut down upon reduction of wartime demand for lithium chemicals, and until recently there has been no production from the Carolinas. In April 1950 an investigation of the problem of spodumene flotation from North Carolina ores was begun at North Carolina State College Minerals Research Laboratory at Asheville, N. C. This laboratory, operating under the combined auspices of North Carolina State College, North Carolina Department of Conservation and Development, and the Tennessee Valley Authority, undertook the spodumene project at the request of Foote Mineral Co. of Philadelphia. The work, involving a period of 15 months of intensive batch and pilot plant investigation, was completed in June 1951 and resulted in development of a process for concentration of spodumene by flotation which has been hereto unrecorded in the literature. A similar approach has been used before on iron, ilmenite, and other minerals, but the literature shows no record of its having been applied to spodumene. Parts of the process are now being used on a commercial scale at the Foote Mineral Co. plant near Kings Mountain, N. C., which has been in production since July 1951. It is the purpose of this paper to describe some of the results of the investigation. The Orebodies Spodumene-bearing pegmatites occur in a narrow belt 24.5 miles long and 1.8 miles wide extending southwestward from Lincolnton to Grover, N. C. According to statements judged to be conservative, the tin-spodumene belt of the Carolinas contains an estimated 4,300,000 tons of pegmatite ore averaging 15 pct spodumene. This amounts to "a reserve of at least 650,000 tons of spodumene (more than 20,000 tons of metallic lithium) to a depth of 100 ft."&apos; This figure includes only bodies having an average thickness of 35 ft and length of 550 ft. There are hundreds of pegmatites in the belt, many of which are less than 10 ft wide. The largest pegmatite in the area has a maximum thickness of 395 ft and maximum length of 3250 ft.&apos; These larger pegmatites are composed principally

Jan 1, 1954

By George A. Jr. Dornin

A TRULY sound ingot can be made only from steel that is completely deoxidized. Given this condition, there is one further basic requirement-the steel in the ingot must solidify progressively from the bottom to the top. Any method of making the ingot that produces this type of solidification will yield sound products. Since a big-end-down ingot will not satisfy this condition, all sound steel today is produced in big-end-up ingots, the standard tool being the big-end-up mold fitted with some sort of refractory hot top. No one uses hot tops from choice, be cause of the bother and expense involved and because of the low yield resulting from their use-they are used because there has been no alternative where sound steel was required.

Jan 1, 1947

By John Henry Harden

THIS shaft, located in the northern anthracite coal-field about 2300 feet southwest from the court-house at Wilkes-Barre, in the County of Luzerne, Pa., is the property of the Lehigh & Wilkes¬Barre Coal Company. The sinking and cribbing to the solid rock (see isometrical view on Plate IX) was conducted by Mr. W. W. Kenrick. Dimensions of the earthwork to the foundation of the cribbing, 51&apos; 1/2" long, 17&apos; 4" wide, 31&apos; deep. Total amount of excavation in cubic yards, 998.5. Dimensions within the permanent cribbing, 45&apos; 4" long, 11&apos; 16" wide, 31&apos; deep, divided into six parts by buttons 8" x 12", each division, 7&apos; x 11’ 16". Permanent cribbing 12" x 12"; temporary cribbing 8" x 10"; backing, 3" thick ; clay puddle to ex¬clude surface water, 12" thick; conductors, 8" x 5"; lining, 1" thick from top to bottom of the shaft. In the latter part of the year 1871, Mr. H. Murray & Son contracted with the company for the continuation of the work at the rate of four hundred dollars per yard in depth, to a point 100 feet below the Hillman seam of coal ; for the succeeding 100 feet the price to be increased twenty-five dollars per yard, and so on until the bottom rock of the Baltimore seam of coal was found. The size of the shaft within the cribbing timbers is 45 feet 4 inches by 11 feet 6 inches, having six divisions of equal dimensions, 7 feet by 11 feet 6 inches, giving room for what is known as the" standard diamond" car, whose capacity when level full is 100 cubic feet, but when loaded by the miner 4 inches above the top contains 112 cubic feet.* Two divisions of this shaft are intended for hoisting coal from the Hillman seam, two from the Baltimore seam, one for ventilation, and one for pumps. The works were planned for two pairs of direct-acting, high-pres¬sure engines, twenty-four boilers, and for an estimated output of 2500 tons of coal per day from the two seams. * Size of the "standard diamond" car, 8&apos; 10” x 4&apos; 3" x 2’ 8” = 100.1.4; loaded 4 inches above the top, 8&apos; 10” x 4’ 3” x 3’ “0"= 112.7.6.

Jan 1, 1877

J. J. RUTLEDGE,* McAlester, Okla. (written discussiont).-Research work has often a more immediate and practical application to the in-dustries than even the investigators themselves realize, but coal mining has not attracted the investigator, except in so far as the mine-accident prevention work and fuel investigations are concerned. In future, the coal geologist will study the subsurface geology of the various coal seams as the petroleum geologist now studies the oil sands, and from the results of these studies the coal operator will be able to locate his shafts to the best possible advantage and to avoid faults that would interfere with underground work. There would have been many thousands of dollars saved, and perhaps some reputations, if a good stratigrapher. had been called into consultation in the southern part of Somerset County, Pa., where a local seam of coal, quite thick, was mistaken for the Pittsburgh seam, which, if ever present at that point, had long since been eroded. Why will the Quemanhoming coal carry more sulfur without injuring the grate bars than George&apos;s Creek Big Vein? Only the investigator can answer and yet the fact that the above is true means a greater price for the thinner coal. The owner of the land in Oklahoma receives one-fourth of the cotton crop produced by the tenant who farms his land and one-third of the

Jan 11, 1919

By G. W. Tracy, R. D. Carter

Numerical calculations were made to determine the behavior of reservoirs with high-pressure drawdown and wide well spacing where the initial productivity is low and the wells are completed by hydraulic fracturing. The two-phase flow equations were solved for the flow into a single well. This well was assumed to be producing from a reservoir with hydraulically created horizontal fractures (four different systems with fractures were studied). For comparison purposes, additional two-phase flow calculations were made assuming a reservoir with uniform rock properties. The two-phase flow results were also compared with the conventional calculation methods, which do not include the effect of saturation gradients resulting from a simultaneous flow of oil and gas which are normal to this type reservoir. It was found that the conventional methods predict (1) a high and too optimistic value of ultimate recovery, (2) a high producing rate and a high reservoir pressure at a given oil recovery and (3) a low trend of gas-oil ratio with oil recovery. Included in the two-phase flow calculations were provisions to control the oil production rate by an allowable rate and, also, by a gas-oil ratio penalty rule. For the systems with hydraulic fractures, the producing rate was controlled by the gas-oil ratio penalty rule for most of the life. This is in contrast to the system with uniform rock properties which went "on decline" almost immediately. An unexpected characteristic of the systems which included fractures was the early rise in producing gas-oil ratio from 730 cu ft/bbl to approximately 1,200 cu ft/bbl, followed by a "leveling off" before the normally expected gas-oil ratio rise began. Additional features which are a result of hydraulic fracturing are (I) greater ultimate recovery, (2) higher average producing rates and (3) a lower average reservoir pressure at a given oil recovery. INTRODUCTION Some oil fields discovered during the past few years are producing from certain volumetric ally controlled reservoirs (often referred to as solution or internal gas- drive reservoirs) which are characterized by high-pressure drawdown at the wells. Since the available pressure drawdown at a well is limited by the static reservoir pressure and the producing rate is controlled by the available drawdown, wells completed in this type of reservoir usually produce at a rate less than the allowable from the time of completion. Because of this, this type of reservoir is referred to as a low productivity reservoir. Economic considerations require the use of wide well spacing and well stimulation by hydraulic fracturing to make commercial wells in this type of reservoir. Performance predictions for volumetrically controlled reservoirs have been made using a combination of two standard equations. 1. The "Schilthuis" or "Muskat" type material balance equation is used to relate the average reservoir pressure and the cumulative oil recovery. 2. The results from the material balance equation and the productivity factor as described by Pirson&apos; are used to relate the cumulative recovery with producing rate and time. The material balance equation assumed uniform pressure and liquid saturation conditions throughout a reservoir. The steady-state radial flow formula allows for a pressure gradient toward a well but assumes uniform liquid saturation. These calculation methods are adequate for application to reservoirs wherein the drawdown at the well to realize satisfactory producing rates is small compared to the total pressure. In low productivity, volumetrically controlled reservoirs, the pressure drawdown at the well is large cornpared to the total pressure. Although a precise number cannot be given for the magnitude of a large pressure drawdown, values in excess of 1,000 psi would definitely be included. For practical considerations, this usually occurs when the formation flow capacity is less than about 100 md-ft. However, this limit of formation flow capacity will vary with the well producing rate. The low pressure in the neighborhood of the well which results from a high drawdown causes evolution of large volumes of gas. This causes the gas saturation to be higher near the well than at a greater distance—-hence, a non-uniform gas saturation. Also, the relationship between the relative permeability to oil (K/K) and gas saturation is nonlinear but decreases approximately in an exponential way with increases in gas saturation. Because of this, the following chain reaction is established.

By Frank Gilbreth

THE problem, of the crippled soldier in industry is not a problem of war work only; it is a problem of industrial development. As individuals, each one of you is seeking to provide our maimed heroes with such teaching as will render them, in the shortest possible amount of time, productive and satisfied members of the community. As individuals you are interested in the organizations that are preparing to receive these men, to train them and to place them at that work for which they are best fitted. As an organization, it is now your duty to take up the industrial end of the problem, to investigate existing conditions in the industries, to discover where the opportunities for employment lie, and so readjust industrial practice that the cripples may be utilized to their own and the community&apos;s good with the least shock to themselves or to the industries, and with the greatest amount of permanent benefit to all concerned. We have divided industrial opportunities suitable for cripples roughly, into three classes. First, such as already exist in the industries, which can be set aside for cripples only, present occupants being transferred to other work for which they can be fitted but which is not suitable for cripple work; second, opportunities in the industrial world that, through changes in the working equipment or tools, or through appliances attached to the cripple himself, can make the cripple a competitor of the sound worker; third, opportunities not existing at present in the industries, but which could be introduced for the good of the community, without placing the cripples into competition with any existing class of workers.

Jan 4, 1918

By F. E. Buch

THE Smelter is designed for a production capacity of 10,000 short tons of blister copper per month, when operating on the present concentrate grade. The Smelter lay-out is shown in Fig I. The major units of equipment comprise two reverberatory furnaces, three 13 by 30 ft Peirce-Smith converters, two straight line casting machines, one being served by a 13 by 30 ft holding furnace and the other by a ladle tilting quadrant, two converter ,aisle cranes and two converter blowers. The plant is compact and the general arrangement of standard gauge railway tracks and conveyor belts provides for a smooth flow of incoming materials and metallurgical products. Concentrate is received by conveyor belts and fluxes in standard railway trucks. The local track system is covered by an electric trolley locomotive. The Smelter treats a wet (10 pct moisture) flotation concentrate containing approximately 53 pct total copper and 0.9 pct oxide copper. The predominating minerals are chalcocite, chalcopyrite and bornite accompanied by small quantities of malachite and cuprite. The gangue is highly siliceous and requires limerock as a flux. Metallurgy would be straightforward were it not for the necessity for eliminating k bismuth which occurs as an impurity in the ore along with the copper. Directly or indirectly most of the Smelter problems can be traced to the necessity for bismuth removal. Copper recovery, based on new copper treated, averages 97.5 pct. GENERAL DESCRIPTION Flotation concentrate, containing to pct moisture, is conveyed from the filter plant to the smelter storage bins by conveyor belts, the material being weighed in transit by a revolving drum type of weigh-hopper manufactured by Samuel Denison and Son, Ltd. The weigher consists of a steel drum with dished ends carried on a horizontal shaft and rotated by an 8 hp squirrel-cage motor through a worm and spur reduction gear. A feed mouth in the drum permits of filling and discharging. The whole unit is supported on a framework resting on weighing levers, which in turn connect to transfer levers, thence to an indicator of the steelyard type situated 16 ft from the centre line of the drum. The indicator is of the "Denison" patent equilibrium controlled ticket stamping type, insuring mistake-proof records by a combination of electrical and mechanical movements which prevent the operator from printing until the cover enclosing the steelyard is closed and until the poise-weights have been set correctly to the weight of the hopper and contents. The machine is capable of weighing 30 short tons at a time but the usual load is 28 tons. After obtaining the gross weight the drum is rotated and discharged into a receiving bin situated below it. The empty drum is weighed and the net weight re-

Jan 1, 1947

By H. P. Rassbach, E. R. Saunders

MUCH progress has been made in recent years in the theory and practice of making stainless steel. By effective utilization of oxygen for decar-burization and more suitable alloying agents, it has been possible to attain consistent production of very low-carbon stainless steel. In order to facilitate economical production of stainless steels, the Electro Metallurgical Co. has carried out an extended experimental program that has clarified some of the complex interrelations of temperature and composition under decarburizing and reducing conditions. These results&apos;-:&apos; have been founded in large part on small experimental heats, and in order to confirm their validity and significance under commercial conditions, a survey of stainless steel melting practice has been made with the cooperation of stainless steel producers. Conditions required for decarburization and associated oxidation of chromium, manganese, and iron have been fairly well established in relation to the beneficial effect of the highest practicable temperature. The recovery of chromium and manganese from highly oxidized slags by reduction with silicon has been indicated with somewhat less precision and this study has shown significant deviation in large commercial heats from the small experimental heats. In spite of an unsatisfactory degree of accuracy in estimating the conditions affecting reduction of metallic values, it has been possible to calculate a slag weight in reasonably good agreement with the results observed in large heats. While there still is much to be learned about both the qualitative and quantitative aspects of stainless steel melting, this survey has indicated the manner by which the efficiency of the production process may be measured. Oxidation Period In order to establish practices for the recovery of chromium and manganese from the slag the amounts of these metals oxidized should be known. Moreover, since reduction of oxidized chromium and manganese must necessarily be accompanied by similar reduction of iron, knowledge of the total quantity of metallics oxidized is essential. The relations between carbon, chromium, and temperature under oxidizing conditions were developed by Hilty in 1948.&apos; While it had been realized previously that retention of chromium in the metal during carbon oxidation is favored by high temperatures, the Hilty relation provided quantitative information useful for evaluating melting procedures. For example, it was shown that decarburization to moderate carbon levels can be achieved while retaining substantial amounts of chromium. However, in decarburizing to the low-carbon level necessary for producing 0.03 pct maximum carbon stainless steel, very little chromium remains in the bath at the temperatures generally employed. For this reason, Hilty, Healy, and Crafts&apos; later projected an extension of the chromium-carbon relation to the low-chromium region. Although this chromium-carbon-temperature relation defined the composition of a chromium steel bath at the end of the oxidizing period, it did not provide a direct means for estimating the total amount of metallic oxidation occurring during decarburization of a stainless steel heat. This subject was investigated by Crafts and Rassbach³ and, later, by Hilty, Healy, and Crafts" who demonstrated that metallic oxidation is a function of the chromium content of the initial furnace charge, the minimum carbon content attained, and the temperature. It was further demonstrated from data on 1-ton heats that an empirical relationship exists between the ratio of chromium plus manganese to iron in the slag (S) to the corresponding ratio of these components present in the metal bath. The following expression was derived to permit the calculation of the amount of metallics oxidized during decarburization of a given charge: W-2000 (Cr1 + Mn1)-(Cr2 + Mn2) 1 100s/s+1-(Cr3 + Mn2) where W is the pounds of chromium, manganese, and iron oxidized per ton of charge; Cr1, the percentage of chromium in the charge; Mn1, the percentage of manganese in the charge; Cr2, the percentage of chromium in the bath after oxidation; Mn2, the percentage of manganese in the bath after % Cr + % Mn oxidation; and S =%cr+ % Mn/%Fe in the slag after %Fe oxidation. In order to establish whether the slag ratios of commercial heats are consistent with those found in the experimental heats, the slag and metal analyses shown in Table I were evaluated. These data represent samples taken after the oxidation of two 1-ton and seven 15 to 25-ton heats of types 303, 304, and 304L stainless steel made in chromite, acid, and basic hearths. Fig. 1 illustrates that the results for the commercial heats correlate reasonably well with the relationship originally established for experimental 1-ton heats. It will be noted that in the range of metal composition of these heats, the slag values generally lie above the line. As was suggested by

Jan 1, 1954

By Edgar C. Bain, William E. Griffiths

The results of an inquiry into the structural nature of some 70 iron alloys containing both nickel and chromium over a considerable range of concentration are briefly described in this paper. This study is a part of a comprehensive program of investigation into alloys involving chromium in progress at the Union Carbide and Carbon Research 1aboratories. All the compositions studied contained carbon in amount comparable to commercial alloys. The B Constituent In addition to locating the limits of composition for the three principal types of structure (polyhedral ferrite, martensite and austenite) and their combinations, certain other features of the system were observed. A hitherto undescribed brittle constituent (designated here as the "B constituent") was discovered. It is very hard, non-magnetic and forms in two modes from chrome-ferrite by recrystallization. It is the stable low-temperature condition for the equal-proportion chromium-iron materials containing less than 10 per cent. nickel. Although it partakes of the nature of an inter-metallic compound, yet it may exist over a considerable range of composition. It is non-existent above a temperalure zone, varying with composition, from 800° C. to 950° C., and heating above this critical temperature develops chrome ferrite persistent after average cooling rate; a few hours just below this temperature will develop the complicated brittle crystalline type. The B constituent, when found in the grain boundaries of alloys of lower chromium content, contributes a serious brittleness removable, however, by heating and cooling rapid enough to prevent its re-format&apos;ion. By suitable means of precipitution, the hard B constituent can be made to strengthen the already stiff alloy matrix in the manner of submicro-scopic particles, as exemplified in duralumin or the Sykes iron-tungsten and iron-molybdenum alloys. A possible explanation is offered for the familiar brittleness developed in chrome iron at temperatures above about 475" C. and removable by

Jan 1, 1927

By A. W. Hesse

VENTILATION of all types of coal mines is fundamentally the same, in that sufficient air must be provided to properly dilute and remove dangerous and obnoxious gases and leave the oxygen content of the air not under 19 per cent in all places where men and animals must work. Perhaps animals should not be mentioned, as the speed of mechanical loading leaves livestock behind and outmoded. Since this paper has to do with the influence of mechanical loading equipment on ventilation, the problems will be confined to the splits and the coal-producing places of the mine. The removal of coal dust from the air, or its rapid transmission to the return air courses; the possible increase in the liberation of gases by the multiplication of cuts in the coal made during one shift or multiple shifts; and the additional electrical equipment at the faces, are the factors that cause the added importance to good ventilation in the permissible equipment area of gassy bituminous coal mines. VENTILATION FOR MECHANICAL LOADING IN GASSY MINES In gassy mines, the air currents must be maintained across the faces in such a way as to prevent short cuts to the returns and leaving pockets in which accumulation of gas might occur. To do this, two or more doors are required on almost every entry containing a track to the face, so located that in no event will a trip of cars block open the doors and permit the air to by-pass some place or places on the air-approach side. This method frequently requires the use of unusual lengths of duplex cables to reach the mechanical equipment at the faces, particularly where the distances between parallel working places are 100 ft., as at the Nemacolin mine. Fig. I shows a pillar section being worked with mechanical loaders. This layout requires carrying the air in on the right and releasing it on the left, because the track clearance is on the right side and the line brattice is built on this side from the last crosscut to the face. Thus, the air travels to the face with greater velocity, and gives more assurance of sweeping out the gas that might be exuding from the crevices of the coal. All working places, in driving through solid coal, are thus treated alike. They are all potentially gassy and must be swept clear of whatever may contaminate the air. Once the air starts into the working section, it is not released until it does a good job. Of course the volume of air must be large enough not only to dilute the gases but to carry away explosive fumes and fine coal dust quickly. Mechanical loading entails cutting and drilling of the coal during the same working period as the loading when two-shift and three-shift operations are employed, and all three processes create finely pulverized coal, which in itself is hazardous if not controlled by some means. If the ventilation is inadequate and gas accumulates, and a spark from defective electrical

Jan 1, 1941

By C. F. Floe, M. Cohen, M. B. Bever, V. G. Paranjpe

NITROGEN is becoming recognized as one of the important elements in ferrous physical metallurgy. Several investigations indicate that nitrogen plays a significant part in such phenomena as strain aging and temper brittleness. Nitrogen is known to be a powerful austenite stabilizer and may be a useful alloying element in stainless steels. The hard-enability of steels has been found to be increased by nitrogen. The nitriding and carbonitriding pro- cesses are examples of successful industrial application of nitrogen in ferrous materials. For a complete understanding of the various roles played by nitrogen in ferrous metallurgy a knowledge of the phase relations in the binary iron-nitrogen system is essential. The literature contains a variety of iron-nitrogen phase diagrams. Those suggested by Fry, Sawyer,² Epstein and his coworkers,³,4 Lehrer,5 Eisenhut and Kaupp, and Hägg7,8 differ significantly from one another. Moreover, the most recent of these investigations dates back about twenty years. A re-determination of the entire diagram, therefore, appeared desirable. In addition to the published phase diagrams, investigations have been carried out on portions of the iron-nitrogen system. Bramley and Haywood determined the composition and temperature of the iron-iron nitride eutectoid. The maximum solubility of nitrogen in a iron was investigated by Portevin and Seferian10 and by Diikstra. 11 Several investigators have determined the crystal structure of the various iron-nitrogen phases. In fact, Eisenhut and Kaupp6 and Hägg7 based their entire phase diagrams on the results of such studies. Epstein&apos; and Emmett12 reported lattice-parameter measurements on the E (hexagonal close-packed) phase. Osawa and Iwaisumi13 also studied the change in lattice parameters of the a, ? and E phases with nitrogen content. Brill" and Hägg7 showed that the y&apos; phase has an ordered structure, and Hendricks and Kostingsl5 suggested a structural relation between the E and phases. In a recent investigation Jackl6 arefully studied the super-lattice reflections from the y&apos; and phases. Experimental Procedure A large variety of experimental methods has been used by previous investigators in studying the iron-nitrogen system. These methods include thermal analysis, microscopic examination, X ray diffraction, magnetic measurements, dilatometric analysis and anelastic experiments. Thermal analysis is of low accuracy in determining changes in the solid state. This accuracy is further decreased for iron-nitrogen alloys since composition changes will occur during heating or cooling unless extreme care is taken to use a proper atmosphere. Metallographic methods are of small value . because homogeneous iron-nitrogen alloys of sufficient size can be produced only with great difficulty. The dilatometric method is open to the same objections as thermal analysis in that changes in composition may occur during heating and cooling. Lattice parameter measurements by X ray diffraction can be used satisfactorily for determining phase boundaries if cooling is fast enough to prevent structural changes. In view of the limitations of the various other techniques two methods only were adopted in this investigation, (1) X ray diffraction measurements, and (2) a controlled nitrogenizing method. The second method is an innovation for investigating the iron-nitrogen system, and will be described at length. Materials: All iron-nitrogen alloys were prepared from carbonyl iron powder of the analysis shown in table I. The average particle size was about 20

Jan 1, 1951

By W. Mostowitsch, H. O. Hofman

In a previous paper,&apos; The Behavior of Calcium Sulphate at Elevated Temperatures with Some Fluxes, we published the results of our investigation into the behavior of calcium sulphate in air; that is, under oxidizing conditions. The results as a whole hold good for a neutral atmosphere, or one which has no chemical effect upon calcium sulphate. The present paper deals with the behavior of calcium sulphate under reducing conditions, the reducing-agents employed being carbon monoxide and carbon, and the changes the calcium sulphide formed undergoes when it is subjected to an oxidizing-roast. Technical literature deals very sparingly with the subject. The information furnished by the recent leading chemical manuals is general. Thus Dammer,2 Missan,3 and Abegg4 quote Berthier as having reduced, in 1823, calcium sulphate with carbon, and Stammer as having done the same in 1851

Jan 1, 1911