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By Lawrence K. Nordell

This paper reviews practices used In the selection and sizing of belt conveyors and stacker systems commonly used in crushing and grinding plant facilities. Historical and modern methods of sizing this equipment are presented. The new methods Include: 1) probability theory applications for establishing component reliability, 2) "Monte Carlo" simulation techniques used in evaluating alternative system designs and in establishing service factors and corresponding availability Indices of each system, 3) quantifying the system and component operating characteristics using computer assisted modeling tools simulating rigid body and elasto-mechanic behavior for starting and stopping large and/or complex belt conveyors.

Jan 1, 1982

By W. O. Philbrook, H. W. Hosking, N. B. Melcher

Rates and patterns of gas flow in an experimental blast furnace were investigated by measurements, at three levels, of gas compo-sitions and temperatures and by direct determination of gas transit time by a new method employing mercury vapor as a tracer. Infer-ences were drawn about localized reaction zones and the mechanism of the onset of' channeling. LACK of precise knowledge of the nature of gas movement in the blast furnace has always been an impediment to better understanding of the blastfurnace process as a whole. The effects upon operation of various types of charge distribution are very largely brought about by the modifications to gas flow which they occasion. Intelligent evaluation of these effects demands a better understanding of the factors influencing gas flow and the ways in which the flow pattern is altered by conditions existing in the stock column. The same knowledge is required before a fundamental approach can be made to the problem of establishing optimum lines for new furnaces. An experimental furnace is operated at the Bureau of Mines Central Experiment Station, Pittsburgh, Pa. Advantage was taken of experimental operation to conduct an investigation to develop and evaluate methods of study which could be applied later to industrial furnaces. The gas composition and temperature determinations were made as a preliminary study so far as gas flow was concerned but yielded significant information relating to other processes occurring within the furnace. The direct measurement of gas transit times by the mercury-vapor method constituted the major object of the investigation. Development of the mercury-vapor method was carried out while the data on gas composition and temperature were being collected. A complete description of the principle and development of the mercury-vapor method is beyond the scope of this paper but is available elsewhere. The results obtained and some consideration of the method's effectiveness and its potential value in the study of industrial problems will be treated here. DESCRIPTION OF FURNACE The general lines of the experimental blast furnace are shown in Fig. 1. The hearth diameter was 3 ft at the beginning of the investigation, and this was later enlarged to 3 ft 9 in. and finally to 4 ft to increase capacity. Tuyere to stockline height is 21 ft 4 in. The bosh depth is 3 ft 4 in. over which it opens to a width of 5 ft, and this diameter is carried up for 2 ft in a cylindrical section. The inwall batter of 1/2 in. per ft. is considerably less than in larger installations This may have influenced the movement of gaseous and solid materials. The furnace is inside a laboratory building and is charged from outside by a skip and hoist. Feeding into the first of three bell chambers, the stock is distributed by rotating the upper bell, the other two being used to obtain an effective gas seal. Three water-cooled tuyeres, with a nozzle dia-

Jan 1, 1960

By J. V. Emmons

IT has long been known that the outside skin of tool steel frequently exhibits properties widely different from the interior of the mass. Within the last few years it has been generally recognized that many of these properties were clue to surface decarbonization. The origin and effects of this altering of the composition have been but little studied. C. M. Johnson' arrives at the conclusion that, in annealing, "the most active agent in surface decarbonization is the rust or scale (present on the surface), which is actually reduced to metal at the expense of the carbon in the steel to which it adheres." W. H. Hatfield in his admirable paper, The Chemical Physics Involved in the Decarburization of Iron-Carbon Alloys,' has given us the most tenable theory of the removal of carbon from iron. While Mr. Hatfield's work has been principally clone in connection with the annealing of white cast iron to produce malleable castings, it is frequently applicable to the decarbonization of tool steel. The following equations which he proposed have been fully borne out by the author's experiments: 2Fe3C + 2CO2 = 3Fe2 + 4C0 2C0 + 02 = 2C02 Continuous 2C02 + 2Fe3C = 3Fe2 + 4C0 It is the purpose of the author to show, in a quantitative manner, the effect of various treatments in eliminating the carbon in tool steel. Some of the phenomena of the decarbonized surface will also be described, as well as the practical problems they present to. the manufacturer and user of tool-steel products.

Jan 9, 1914

By R. H. Heyer, J. L. Bray, M. E. Carruthers

It is well known that iron markedly improves the physical properties and casting characteristics of aluminum bronzes. The use of 1 to 4 per cent iron as the principal modifying addition has become common practice in many foundries melting aluminum bronzes. Although the beneficial effects of iron are unquestioned, there is some uncertainty regarding the structural changes caused by it in the basic copper-aluminum system. It is agreed that a new constituent appears in abundance when the iron content reaches 2 to 4 per cent. This constituent, which frequently occurs in shapes resembling clover leaves, is sometimes assumed to be an aluminum-iron intermetallic compound. If this were correct we might expect a change in the structural relationships of the matrix in the direction of decreased aluminum content. On the other hand, it has been reported that iron has a negligible effect in altering the fundamental relationships of copper-aluminum alloys1 Others2'3 have reported an additive coefficient. Apparently it will be necessary to know the equilibrium relationships between the phases of the copper-aluminum-iron alloy system to establish any such theory as fact. When this has been done it may very well be that a further revision in the structural relationships may be necessary to describe the changes to be expected in commercial cast alloys. It was with this latter problem before them that the authors attempted to determine the change in the copper-aluminum relations with respect to iron. Objects of the Investigation In certain investigations carried out by the authors for a plant producing a large tonnage of cast aluminum bronzes the structures

Jan 1, 1936

By F. F. Lines

It is not the intention of the writer to enter into a discussion of the relative merits of the duplex process as compared with the straight scrap and pig iron process, working under the same conditions, but rather to present in a general way several modifications of the former process, and then describe the method adopted by the Maryland Steel Co., as best suited to local conditions, and also to meet the metallurgical problem presented in the removal from the iron of an unusual constituent— chromium. The principal factors to be considered in. deciding whether or not duplexing should be employed are: (1) Chemical constituents of pig iron. (2) Variety and quantity of steel to be produced. (3) Relative cost of pig iron and scrap. (4) Regularity of operation. (5) Capital to be invested. (6) An existing Bessemer plant. Having decided to adopt the duplex process, several combinations may be used, viz.: (1) Acid-lined converter with basic open hearth. (2) Acid-lined converter with electric furnace. (3) Basic-lined converter with basic open hearth. (4) Basic-lined converter with electric furnace. (5) Basic open hearth with electric furnace. The combination of an acid-lined converter with a basic open-hearth furnace is the one most commonly employed, and as it is the one best adapted to the conditions encountered at the plant of the Maryland Steel Co., we will briefly outline the advantages and disadvantages of the different methods of working. There are two general methods of blowing, as follows: (1) The charge is desiliconized and partly decarbonized in the converter. On account of the difficulty in regulating the percentage of car-

Jan 1, 1916

By B. K. Larkin

Solutions to the diffusion equation for a line source located anywhere in a region bounded by a circular discontinuity are presented. Such solutions follow automatically from the Green&apos;s function presented by Jaeger.4 Petroleum industry applications of this problem would include transient compressible fluid flow in porous media bounded by a discontinuity. Since several recent papers have treated the subject in less general form, it would appear that many workers in this area of the petroleum industry are not aware of Jaeger&apos;s work. STATEMENT OF THE PROBLEM In several trearments1,2,3 of the transient flow of compressible fluids in porous media it was convenient to consider a region to be bounded by a circular discontinuity. In such a region (Fig. I), the properties in Region 1, r < a, are constant but different from the properties in Region 2, r > a. Hurst, l using the Laplace transform, obtained solutions for a line source located in the center of such a porous medium. The purpose of this work is to point out that a much earlier paper by Jaeger4 presents the solution for a line source located anywhere inside the discontinuity. The assumption is made that a line source may be used to approximate a well. In the following material it is convenient to use the terms source and well as being equivalent; however, the reader should remember the distinction in applications. SOLUTIONS Jaeger presented the Green&apos;s function for a line source, or well, in the composite region shown in Fig. 1. In the most general form, the solution for a system of j wells in Region 1, each producing at a time varying rate, qi (t), is

By M. G., Corson

1. In addition to the alloys of copper with iron previously found by Hanson and Ford to show an increase in the concentration of the alpha range with increase in temperature the following binary and ternary systems have been found by the author to exhibit: the same feature: (a) Copper-chromium. (b) Copper-cobalt. (c) Copper-silicon. (d) Copper-nickel-silicon and its pseudo-binary section Cu-Ni2Si (formula of compound definitely established). (e) Copper-cobalt-silicon and its pseudo-binary section Cu-Co2Si (formula of compound established with some probability but not as definitely as for Ni2Si). (f) Copper-chromium-silicon; formation of a compound definitely established (compare Figs. 1 and 2). The formula of this compound may be either Cr2Si or Cr3Si. (g) Copper-iron-silicon; presence of a phase containing both iron and silicon established in an indirect way only. No definite microconstituents observed. 2. RANGES OF SOLID SOLUBILITY (percentage at various tempera¬tures). (a) For copper-chromium: 0.8 at 1000° C.; 0.5 at 900° C.; 0.25 at 800° C.; 0.05 to 0.1 at 500° C. (b) For copper-cobalt: 3.4 at 1000&apos;C.; 2.4 at 900&apos;C.; 1.7 at 800&apos;C.; 0.9 at 600°C.; 0.35 at room temperature. (c) For copper-silicon (Fig. 3) : 6.8 ± 0.1. per cent. at 800° C.; 3 per cent. at 400° C. and probably below 2 per cent. at room temperature if sufficiently long annealed. (d) For copper-cobalt silicide: 3.3 at 1000° C.; 2.4 at 900° C.; 1.6 at 800° C.; 0.7 at 600° C.; 0.3 at 300° C. (e) For copper-nickel silicide (Fig. 4): 8.2 at 1000° C.; 5.5 at 900° C.; 3.6 at 800° C.; 1.6 at 600° C.; 0.7 at 300° C.

Jan 1, 1927

By W. H. Echols

An oil-emulsion mud, consisting of a mixture of oil-base mud and bentonitic water-base mud, has been used experimentally in drilling 8 of the 35 wells in the Sivells Bend field, Cooke County, Texas. Experience indicates the oil-emulsion mud can be controlled in much the same manner as a water-base mud, and the "drilling" functions of the two types of mud are comparable. The average water-loss for the oil-emulsion mud was 3.8 cu cm per well. When using oil-emulsion mud to drill the last 2000 ft of 7000 ft wells, the mud costs were approximately 2½ times that of water-base mud. There is nothing to indicate well productivities have been affected through the use of oil-emulsion mud. However, drilling time and bit footages were increased and the holes were maintained more closely to bit guage. The apparent advantages gained through the use of oil-emulsion mud in the Sivells Bend field do not appear to justify the increase in mud costs. Introduction until a comparatively few years ago most of the development of drilling mud was directed toward improving the functions of the mud as related to actual drilling operations. The industry has long recognized that one disadvantage of rotary drilling over cable-tool drilling is the possibility of injury to producing zones through the blocking effect resulting from the infiltration of water or mud into the sands. Recognizing this disadvantage, considerable attention has been diverted toward the development of muds that will improve the quality of well com-pletions through the reduction or elimination of water into the sands, but without sacrificing too many of their "drilling" functions and at a cost commensurate with the benefits derived from their use. This phase of mud research has already found practical application, for example, in the development of the Rangely field, Colorado, it appears the use of oil-base mud during drilling-in operations will contribute appreciably toward making this exploitation more profitable. Much of the discussion to follow will be better understood if a brief sketch of the Sivells Bend field is given. The Sivells Bend field, discovered by The Texas Co. in 1944 and still in the process of development, is in a large bend on the Texas side of the Red River about 85 miles north of Dallas. Geologically, the structure is an unsymmetrical anticline, with faulting having contributed to its development. The productive sands are of the Strawn series of Pennsylvanian age, the sands being lenticular in character and varying considerably in development from well to well. At Present there are 35 producing wells in the field, producing from seven different sand lenses. The productive sand lenses vary from 15 to 50 ft in thickness and the individual sands have average permeabilities of from 75 to 375 md. The presently productive sands are encountered at depths of from 6300 to 7300 ft, but testing has indicated that commercial production might be obtained from other sands as high as 5200 ft. Histories of older Strawn

Jan 1, 1948

By W. H. Echols

An oil-emulsion mud, consisting of a mixture of oil-base mud and bentonitic water-base mud, has been used experimentally in drilling 8 of the 35 wells in the Sivells Bend field, Cooke County, Texas. Experience indicates the oil-emulsion mud can be controlled in much the same manner as a water-base mud, and the "drilling" functions of the two types of mud are comparable. The average water-loss for the oil-emulsion mud was 3.8 cu cm per well. When using oil-emulsion mud to drill the last 2000 ft of 7000 ft wells, the mud costs were approximately 2½ times that of water-base mud. There is nothing to indicate well productivities have been affected through the use of oil-emulsion mud. However, drilling time and bit footages were increased and the holes were maintained more closely to bit guage. The apparent advantages gained through the use of oil-emulsion mud in the Sivells Bend field do not appear to justify the increase in mud costs. Introduction until a comparatively few years ago most of the development of drilling mud was directed toward improving the functions of the mud as related to actual drilling operations. The industry has long recognized that one disadvantage of rotary drilling over cable-tool drilling is the possibility of injury to producing zones through the blocking effect resulting from the infiltration of water or mud into the sands. Recognizing this disadvantage, considerable attention has been diverted toward the development of muds that will improve the quality of well com-pletions through the reduction or elimination of water into the sands, but without sacrificing too many of their "drilling" functions and at a cost commensurate with the benefits derived from their use. This phase of mud research has already found practical application, for example, in the development of the Rangely field, Colorado, it appears the use of oil-base mud during drilling-in operations will contribute appreciably toward making this exploitation more profitable. Much of the discussion to follow will be better understood if a brief sketch of the Sivells Bend field is given. The Sivells Bend field, discovered by The Texas Co. in 1944 and still in the process of development, is in a large bend on the Texas side of the Red River about 85 miles north of Dallas. Geologically, the structure is an unsymmetrical anticline, with faulting having contributed to its development. The productive sands are of the Strawn series of Pennsylvanian age, the sands being lenticular in character and varying considerably in development from well to well. At Present there are 35 producing wells in the field, producing from seven different sand lenses. The productive sand lenses vary from 15 to 50 ft in thickness and the individual sands have average permeabilities of from 75 to 375 md. The presently productive sands are encountered at depths of from 6300 to 7300 ft, but testing has indicated that commercial production might be obtained from other sands as high as 5200 ft. Histories of older Strawn

Jan 1, 1948

By S. F. Shaw

The Seminole field was first drilled in 1913. During the next 10 years other attempts were made to discover oil in this field, but without encouragement until March, 1926, when the Indian Territory Illuminating Oil Co. completed NO. 1 Dyer in the Hunton lime for 1100 bbl. On July 16, 1926, the Independent-Garland interests discovered oil in the Wilcox formation when No. 1 T. Fixico came in at 4055 ft. and on Sept. 9, 1926, production reached a peak of 8040 bbl. On Aug. 1, 1927, the daily production of the pools making up the Seminole district amounted to slightly over 500,000 bbl., practically all of which was coming from the Wilcox formation. The Hunton formation has not been very productive of oil, but has maintained a fairly high gas pressure; this formation has been encountered at from 3800 to 4200 ft., below which there is about 100 ft. of Sylvan shale. The shale is underlain by 75 ft. of Viola limestone in a few places in which formation oil has been encountered. Below the Viola lies the upper Simpson formation in which is found the Wilcox sand. The depth of the Wilcox in the Seminole field varies from 3900 to 4500 ft., and initial production has reached as much as 12,000 bbl. The gravity of the oil is about 41° Be. The general practice is to set 6 5/8 -in. casing above the Wilcox and drill in, though in several cases 5 3/16-in. casing has been set for the oil string, and in a few instances, casing as small as 4 3/4 in. has been employed. Production Statistics Production for the Seminole district for the various months since its discovery is shown in Table 1.

Jan 1, 1928

By N. A. Zeigler

Considerable work has been and is being done on the changes of physical properties that take place in alloys at elevated temperatures, and much information on this subject is published. Much less is known, as pointed out by Rickett and Woodll about reactions between the alloys and atmospheric gases and still less is known abut changes within the alloy itself under the influence of heat and given atmosphere. Moreover, most of the work published has been done on the alloys of "heat-resisting" type, in which chromium is an essential ingredient, the behavior of all other alloys being quite unknown, except perhaps of decarburization produced at the surface by oxidizing atmospheres. It has been shown2 that iron, with total amount of foreign ingredients not exceeding 0.01 per cent, if heated in an oxidizing atmosphere at above 900" C., may be saturated with oxygen to 0.1 per cent. It was suspected that something of a similar nature may take place in iron-silicon alloys (transformer material), the mechanism of such processes being either a direct diffusion of oxygen into the alloy, or oxygen combining with silicon to form SiO2 or more complicated (silicate) inclusions. Another possibility to be considered was that during annealing in oxidizing atmospheres, when scale is being formed, silicon may oxidize preferentially at the surface, thus impoverishing the alloy in silicon. In collaboration with Dr. T. D. YensenP3 the writer set out to investigate this problem about two years ago in order to settle these questions. Testing Procedure In the first part of the investigation, two pieces of 4 per cent silicon iron, prepared in hydrogen atmospheres and forged to 3/4-in. square bar,

Jan 1, 1934

By John Blatchford, H. O. Hofman

The leading antimony mineral is stibnite. In smelting stibnite ore two processes are available, precipitation and roasting-reduction. The former is suited only for high-grade ores. As low-grade ores are more common than high-grade, roasting-reduction is of greater importance than precipitation. In the roasting process the aim may be to leave the oxidized antimony in the ore, or it may be to volatilize as much of the antimony as possible, collect the volatilized oxide as a rich intermediary product and smelt it for antimony, leaving the gangue poor enough to be considered a waste product. Whichever way the roast is conducted certain difficulties inherent in stibnite are encountered. These are: 1. The low melting point of stibnite which, according to Pélabon,&apos; is 550°C., according to Wagemann2 540°C., and according to Borgstroma 546°C. 2. The ignition temperature: According to Friedrich,4 stibnite, if heated in air, begins to oxidize at 290°C. if the size of a grain is 0.1 mm. in diameter; at 343", if 0.1 to 0.2 mm.; and 430" if 0.2 mm. 3. The fusibility of a mixture of Sb2S33 and Sb203 which in the form of kermesite (Sb2S3)z.Sbz03 melts at 517°C.6 4. The volatility of Sb2Ss and SbzOs, for which no numerical data appear to exist, although practical experience has shown that they are volatile at low temperatures. As regards the oxidation of metallic antimony, we have the experimental evidence of C. F. Plattner6 that when fused and brought to a red heat, it burns with a bluish-white flame to Sb2Oa which passes off as a

Jan 1, 1916

By Y. C. Kim, S. L. Barua

M. Armstrong&apos;s paper is very interesting and can be regarded as a pioneering work of applying geostatistics on washed coal. The density levels used in her study are uniformly spaced, which facilitated curve fitting through a proper experimental design. Most of the existing coal washing plants in the US, however, gather washability data at non-uniform intervals which, in turn, affects the goodness of curve fitting. We would like to emphasize the importance of having a proper experimental design, if a similar geostatistical application is to be conducted on washed coal. We, at the University of Arizona, tried the variogram on recovery (Kim, Barua, and Baafi, 1982, SME preprint 82-143) which showed a similar pattern as Fig. 4 of Armstrong&apos;s paper. In both cases, the first experimental variogram value is invariably and inexplicably higher than the second variogram value. Although Armstrong ignores the first point because of "small number of sample points," we did not do so because there were 17 sample pairs. As a consequence, we concluded that the obtained experimental variogram was unsatisfactory and that further research is warranted. In other words, this disagreement in variogram interpretation between M. Armstrong and the University of Arizona begs the question whether the experimental variogram of Fig. 4 truly reflects the spatial correlation in washed coal, assuming there is such a correlation. Finally, we wish that Armstrong could have done a similar study on clean sulfur, which is a vital interest to the coal mines in the US. Her implied remark on sulfur in the concluding section of the paper may turn out to be incorrect because our experimental variograms on clean sulfur at different density levels were even less satisfactory than those on recovery. ?

Jan 1, 1986

By James Morgan

The convenience of mechanical arrangements for handling ingots, blooms, billets, bars, beams, etc., and feeding them to the rolls, is so universally recognized as to require no demonstration. In the rolling of heavy beams, such as are now coming into general use, such arrangements are practically essential, by reason of the difficulty and expense of the manual handling of the large masses of metal treated. I submit herewith the drawings of a rolling-mill feed-table, designed and patented by myself, which I think will be found simple in construction and operation, not likely to get . out of order, and efficient in performing the work for which it is intended. Fig. 1 is a sectional plan, taken on the line I I of Figs. 2 and 3. Fig. 2 is a vertical longitudinal section on the line II II of Figs. 1 and 3. Fig. 3 is a vertical cross-section on line III III of Figs. 1 and 2. As the details of the drawings are numbered throughout, and the same number always indicates the same part, I cannot more clearly describe the mechanism than by giving the following key to these numbers: Nos. 2 and 3 are the sets of rolls (here shown as three-high rolls, though that is not absolutely necessary). Nos. 4, 4 are the two feed-tables, one on each side of the rolls. The uide frames of the tables are made of parallel channel-bars. Nos. 6, 5 are the feed-rollers, journaled between the channel-bars and provided at their ends with beveled gear-wheels, 6, 6, which mesh with beveled pinions, 7, 7, on shafts, 8, 8, which latter are driven by elevated power-connections, to be mentioned presently. The tracks, 9, 9, on which the supporting-carriages are mounted,

Jan 1, 1891

By F. G. Tahmoush, N. J. Grant, E. P. Abrahamson

The effect of grain size on the brittle -ductile transition temperature of pure iron and three dilute Fe-W alloys has been investigated by slow bend tests. The brittle-ductile transition temperature for pure iron increased with increasing grain sizes from 8000 to 500 grains per sq mm where the transition temperature then decreased with further increase in grain size. The dilute additions of tungsten lowered the transition temperature for fine grain sizes, suppressed a reversal of the curve in the coarse grained portion, and raised the transition temperature for this region. The frequency of twin occurrence increased with increasing grain size and decreasing temperature. The object of the present investigation was to re-examine the effect of grain size on the brittle -ductile transition of pure iron and several dilute Fe-W alloys. Current literature normally presents a simple relationship between grain size and the brittle-ductile transition temperature, namely, that the transition temperature increases with increasing grain size. Heslop and etch&apos; have studied the transition temperature of mild steel by V-notch Charpy impact tests for the grain size range between 200 and 6000 grains per sq mm. The result was a linear plot of In 1-1/2 vs brittle-ductile transition temperature, where 1 is the grain diameter. Recent experiments by sipos2 revealed the possibility of a reversal in the slope of the grain size vs transition temperature plot for pure iron; however, his investigation was limited in scope, and the data obtained were insufficient to permit a definitive curve. The present investigation was undertaken in an effort to confirm or extend the grain size effect observed in iron by Sipos. PROCEDURE All alloys were vacuum induction melted, using 99.95 pct Fe containing 0.03 pct 0 and 0.004 pct C. Four ingots were made, ranging from pure iron to iron with 0.035 pct W. The chemical composition of each alloy, after processing, is given in Table I. The four alloys were prepared as 45 lb heats and cast into 4 in. diam by 16 in. molds. They were then extruded into 3/4 in. rods at 1800oF. Specimens for chemical analysis, taken from various positions along the rods, revealed no variation in tungsten content along the length. The extruded rods were reduced to 0.156 in. diam stock by a series of cold swaging operations involving intermediate vacuum annealing treatments. This procedure yielded a final cold reduction in area ranging from 10 to 90 pct. The swaged rods were chemically cleaned, cold pressed to a cross section of 0.10 by 0.18 by 1.0 in. long (2.54 by 4.73 by 25 mm). The specimens were wrapped in iron foil and vacuum sealed (10-4 mm Hg) in quartz. Various heat treatments at temperatures from 700" to 1300oC were utilized to produce grain sizes from 8000 to 1 grain per sq mm. Grain sizes were determined by measuring the average area of grains in a polished section. In specimens with grain size greater than 20 grains per sq mm, the total number of grains in the cross section was counted and then divided by the area to yield grains per sq mm. Grain size was measured both for longitudinal and transverse cross sections. The average of the two measurements was plotted vs transition temperature. An Instron Table Model testing machine was used to determine the transition temperature of specimens tested in three point horizontal bending. The specimen was supported by two 1/4 in. dowels one in. apart. Bending was accomplished with a push rod, the end of which had an 1/8 in. radius. The head speed was 50 in. per min. Temperatures were established through the use

Jan 1, 1963

By E. J. Ripling, S. I. Liu

IT has been shown in a number of recent publications that much information on the mechanical behavior of metals can be gleaned by first deforming test specimens under one set of conditions, and then evaluating the effect of this deformation by means of a subsequent tensile test. A straining procedure of this type has been applied to study the flow behaviors of a number of metals.1, 2 In these studies the prestraining and testing were both tensile strains, while the straining temperature was varied between the prestraining and testing steps. These data indicate that there is a more or less general flow behavior exhibited by all metals which are pre-stretched at one temperature and then tested in tension at a second temperature. Prestraining a metal at a high temperature produces a lower yield strength during the subsequent low temperature strain than would the same total strain at the lower temperature. On reversing the order of the strains, low temperature prestraining produces a higher yield strength during the subsequent high temperature straining than would a single high temperature strain of the same magnitude. Unlike the flow behaviors, the fracturing characteristics of metals when prestrained under one set of conditions and tested under a second set of conditions is quite material dependent. The fracture behavior of a number of steels2" as well as of a commercially pure zinc,4 have been investigated by these two-step tests and was found to depend upon the position of the transition temperature with respect to the prestraining and testing conditions. Since these fracturing phenomena are complicated by the appearance of the transition temperature, it has been difficult to reliably define the basic effect of a two-step straining procedure in fracturing. Metals crystallizing in the face-centered cubic system do not exhibit transition temperature effects so that the mechanical characteristics obtained on these materials could serve as a base for two-step straining behaviors. Consequently groups of specimens of the aluminum alloy 24s-T4 were prestrained various amounts at room temperature in either tension or compression after which these strained specimens were further strained to failure, or tested in tension, at either room or some lower temperature. Other groups of 24S-T4 specimens were prestretched at various low temperatures after which these were tested in tension at room temperature. These straining techniques then made it possible to compare the behaviors of aluminum with the behaviors previously presented for steels. Material and Procedure The commercial aluminum alloy 24S-T4 in the form of 3/4 in. rods was used in this investigation. The material was subjected to the following treatments before machining: 1—resolution treating at 920" & 10°F for 45 min, 2—quenching in water at room temperature, and 3—aging at room temperature for four days. The re-heat treated material was then machined to either of the specimen shapes shown in Fig. 1. Fig. la shows the threaded-end specimen used for prestraining in compression. Fig. 1b shows the specimen used for both prestrain in tension and final testing. The material subjected to precompression in the form of the specimen shown in Fig. la was re-machined to the specimen shape in Fig. 1b for final testing. Prestraining in tension and final testing were done without any intermediate machining. All straining was performed on a 10,000 1b Riehle tensile testing machine. Tensile strains were conducted in a specially designed concentric fixture which produced an eccentricity of less than 0.001 in." The change in diameter at the minimum section of

Jan 1, 1954

By J. A. Bownocker

THE Pittsburgh is one of the most important coal beds of Ohio. It was the last of the great coal beds to be worked extensively in that State, has the largest area of virgin coal, and will in all probability be the last of the great deposits to be exhausted. The line of outcrop sweeps nearly southwest in a sinuous line from Jefferson County on the north to Lawrence on the south, a distance on a bee-line of at least 150 miles. (Fig. 1.) The maximum width of the area under which this coal is due is about 55 miles, but in most places it is less than half that and in the two southern counties it is in places restricted to narrow ridges. Here as elsewhere the Pittsburgh coal forms the base of the Monongahela formation, and the following section taken from Condit shows the position of this bed with reference to certain higher ones in this field:1 FEET INCHES Shales and thin beds of limestone 24 5 Coal, Meigs Creek, No. 9 4 0 Shale, sandy 11 0 Coal 0 8 Shale, clayey 6 0 Coal, Lower Meigs Creek 3 0 Shales,clayey 2 0 Limestones and thin layers of clay 25 0 Unseen 11 0 Coal, Redstone 2 0 Unseen 11 0 Coal, Pittsburgh, No. 8 8 0 Clay 5 0 Limestone 4 0 From the standpoint of continuity the Pittsburgh coal of Ohio must be classed with the patchy type. As the map shows, the coal is thin or wanting along many miles of the line of outcrop. The large deposits form three separate areas, which, in order of their importance, are generally known as (1) the Belmont, (2) the Federal Creek, and (3) the Gallia fields.

Jan 10, 1926

By H. W. Turner

The axis of the middle portion of the Ural mountains is made up chiefly of highly compressed igneous and sedimentary schists, considered of Devonian age by the Russian geologists, with large areas of serpentine (peridotite originally) gabbro, etc,, intrusive in the schist series. In addition there are large areas of probably older granitic and gneissic rocks. The nickel deposits referred to in this paper are found in the Devonian schists and their associated igneous rocks. The gabbro-peridotite intrusions probably took place in late Devonian or early Permian time, inasmueh as the Permian and Carboniferous beds lie at gentle angles on the Devonian series on the west slope of the Urals. Perhaps the first attempt to work a nickel deposit in the Urals was made about 1866 in the Revdinsk district, which is situated southwest of Ekaterinburg. 3 was informed by a Russian that a wet method of extracting the nickel was tried but was not a commercial success. This deposit has been described by Muller,l Foullon, and Karpinski.3 Beck4 gives an abstract of these papers. ; Lying to the southeast of the Revdinsk district, the Sissert estate intervening, is the Verkhne-Ufalei district, which is traversed by the railroad from Ekaterinburg to Cheliabinsk, as shown on the map, Fig. 1, there being a station on this railroad at the iron-smelting town of Verkhne-Ufalci. About 7 versts (4.6 miles) north of this town is the Nijni-Karka-dinsk iron mine, which is a limonite deposit. In one of the shafts in this mine a serpentine rock showing a green mineral was encountered. A sample of this mineral collected in 1910 was tested by Mr. Wyatt, chief chemist of the Karabash laboratory of the Kyshtim Mining Works, and determined as nickel ore. A thin section of one piece of the serpen-

Jan 1, 1915

By AIME AIME

A. A. Holland, Consulting Engineer, Toronto, Ont.-I noticed in this discussion of locations in which radium is found, no mention is made of the recent deposits discovered in Ontario. While radium is not a subject with which I am very familiar, I took an interest in this deposit on account of its novel occurrence. It is found in Haliburton County, near Wilberforce, Ontario, associated with a quartz free pegmatite, in a "break" that I understand can be traced for two miles. This "break" marks the contact between the limestone and syenite and contains numerous cavities or vugs. The gangue, on account of its deep purple, appears to :be amethyst.

Jan 1, 1930

By F. M. Jardine

I1944 the cry was for higher production more tons, more metal. New plants were built, capacity of old plants was increased and millmen all over the country were treating tonnages far above normal, sacrificing recoveries to vet that extra metal from extra tons. The list of "critical minerals," at first long, has been scratched until there remains, not a list, but only an item or two. Stocks of all metals and minerals, with possibly one or two exceptions, are now entirely adequate and numerous plants have curtailed or suspended operation.

Jan 1, 1945