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Jan 4, 1951

By Henry D. Hibbard

The finishing and casting temperature of steel is a subject concerning which there is so much to learn that some temerity is required to write about it. This paper is, therefore, suggestive rather than dogmatic, though the views expressed seem now to the writer to be correct; nevertheless, they may be modified by future developments or discoveries but until then may be of some utility, particularly to beginners in the making of steel. Consideration is limited to the temperatures of simple steels, also called carbon steels, which are those in which carbon is the only element introduced for the purpose of conferring desired physical properties. Alloy steels will receive attention later. Three things largely determine what a batch of steel really will be; via., composition, casting temperature, and rate of teeming. Each has its advocates as being the most important; but they are so interrelated that each must conform to or be right for the other two. When one is claimed to be the most essential to have right, that, probably, was the one that it was found had to be of a certain description, within narrow limits, to suit the already adopted variations of the other two; that is, it was the last of the three to be brought into line. The term "casting temperature" is rather indefinite as there ale several temperatures to which the term may be applied. Most writers who have mentioned casting temperature of steel have alluded to it in relative terms. The few who have given actual temperatures, including Langmuir, Burgess, Styri, and Bash, do not give full information about them. Their results demonstrate the efficiency of pyrometers used rather than aid the steelmaker. In order to understand and use the temperatures, one should know in each case what the steel was, the stage at which the temperature was taken, whether it was usual or not, and whether or not it was right for that steel at that stage. When these

Jan 1, 1925

By Arthur F. Colombo, Donald W. Frommer

With the opening of the Tilden mine near Ishpeming, MI, a new era in iron ore beneficiation was begun. A description of a U. S. Bureau of Mines investigation is summarized to illustrate the selective flocculation-deslime-flotation process developed by the Bureau and used at the Tilden concentrator, which is also briefly described. The operating parameters for the selective flocculation-cationic flotation of an oxidized taconite from the Mesabi range are discussed. A water reclamation system using lime and a cationic flocculant was applied to reclaim the effluents from a 900-pound-per-hour flotation pilot plant. About 80 percent of water requirements were recovered, and the calcium content of the reclaimed water was found to be more important than clarity in influencing the selective flocculation and flotation processes. Although reclaimed waters with about 10 ppm calcium registered turbidities of approximately 5,000 ppm SiO2 equivalents, the concentrates produced using these waters contained 64 percent Fe and 55.0 percent SiO2 and had accompanying iron recoveries of 75 percent. Lower grade concentrates resulted from using reclaimed water with higher calcium contents and lower turbidities.

Jan 1, 1976

By S. L. Lopata, E. B. Kula

A variation of yield and tensile strength with direction has been noted in heat-treated 4340 steel which had been warn-worked by rolling in the austenitic condition prior to quenching. Measurements by X-rays showed a preferred orientation of martensite crystals. Various ideal preferred orientations of martensite were calculated by assuming a preferred orientation for austenite and transforming this to martensite by the Kurdjumov -Sachs and Nishiyama relationships. Comparison with the measured preferred orientation showed that the ideal rolling texture for austenite in 4340 steel could be expressed as a (112) [111] texture with a component of (110) [112]. No evidence was found for any fiber axis in the rolling direction, or fop- a (123) [412] texture. The observed martensite pole figures can be adequately accounted for by these ideal austenite textures and by the Kurdjumou-Sachs or Nishiyama transformation relationships between austenite and martensite. ALTHOUGH preferred orientations are found in cold-rolled steel sheet and in many nonferrous metals, they are not generally encountered in wrought, heat-treated high-strength steels, since such steels are generally not cold worked sufficiently to develop a strong texture, and any texture that is present is removed during heat treatment by the phase transformations taking place. This report gives details on a preferred orientation found in warm-rolled and hardened 4340 steel. In a recent study, a special combination heat-treating and working technique was used in which 4340 steel was deformed in the austenitic condition, and before re crystallization of the austenite could occur, quenched to form martensite.' Since the austenite was unrecrystallized, it was cold worked and hence could have contained a preferred orientation which could be transmitted to the martensite on quenching, and this in turn could be manifested as a directionality of mechanical properties. Such a directionality of properties was found as a result of working, and this prompted an X-ray study of the preferred orientation. Literature Survey— Rolling Texture in Face-Cen-tered-Cubic Austenite—M a preferred orientation is found in a rolled and hardened steel, it is first appropriate to consider what texture existed in the austenite as a result of the rolling but prior to the transformation to martensite. The changes taking place as a result of the austenite-martensite transformation are then considered. In view of the instability of austenite in 4340 steel at low temperatures, no direct determination of the austenite texture was made. However, an estimate of the texture for austenite in 4340 steel may be made by considering the textures found for other face-centered-cubic metals. Barrett' has reviewed the rolling textures for many materials. The most common orientation in face-centered-cubic metals has the (110) planes parallel to the rolling plane and the [112] directions parallel to the rolling direction, or (110) [112]. Other orientations found are (112) [111], as well as (100) [001], (110) [001], and others. Beck and his co-workers, using quantitative pole figures, report that (123) [121],3 later corrected to (123) [412],4 better describes the ideal orientation. smallman5 reported that the ideal preferred orientation for high-purity face-centered-cubic metals is (123) [121], but that there is a transition to (110) [112] as solid solution elements are added. The latter texture tends to occur more readily at lower temperatures. This transition between the two textures was explained by differences in the slip characteristics with concentration or temperature. More recently, Jones and Fell6 concluded that the (123) [412] texture for face-centered-cubic metals could equally well be represented by a mixture of (110) [112] and (112) [111] textures, and hence it had no physical reality. From the above results it can be seen that there is no agreement on the "ideal" texture for fcc metals and, hence, no firm basis for assuming a texture for austenite in 4340 steel. Therefore, the orientations (110) [112], (123) [412], and (112) [111] have been considered in the following.* *The (123) [4121 is identical to the (123) [121] rotated 90 deg. Orientation Relationship between Austenite and Martensite—When martensite forms from austenite, certain crystallographic planes of the martensite are parallel to planes in the austenite. This orientation relationship was first determined by Kurdjumov and

Jan 1, 1960

By R. E. Zimmerman, T. W. Guy

IN approaching the problems of sampling coal, a brief statement of certain facts that are more or less taken for granted may be helpful: 1. The coal-mine operator needs reliable data as to the physical and chemical characteristics of his coal in order to plan and control intelligently its mining, preparation, and marketing. The consumer needs such data in order to select the equipment and the coal best suited to meet his requirements, to check the quality of fuel delivered, and the efficiency of its use. Various government control agencies require such data as a basis for classifications and establishment of limits, for use in carrying out the requirements of federal, state or municipal laws. 2. All such data must be obtained by analyses, measurements, or tests made on samples, which are taken to represent the coal tested. It is now becoming generally recognized that, in accordance with statistical laws, test results from samples are not expected to represent the exact qualities of the lot or lots from which they are taken, except within statistical, or "expected" limits. Such limits are definitely specified by some present standards of the American Society for Testing Materials and the British Standards Institution. 3. Samples that give ash within satisfactory limits are usually assumed to be sufficiently accurate for other analyses, except under special conditions such as meeting close specifications for coals showing wide variability in sulphur, fusibility of ash, or other quality. 4. In modern coal sampling the increment is recognized as the basis for taking samples. For a given accuracy the number and weight of increments specified are increased with: (a) the expected ash, and (b) the top size designation of the lot to be sampled. 5. It is extremely important that every sampler recognize that: the specified number and weight of increments are minimums, and that the precautions to be used in order to take them properly are also minimums; that in the reduction of the gross sample the sizes specified for the coal after each stage of the crushing are maximum; that the quantities specified to be taken after each crushing stage are minimum; that any short cuts or failures to meet the requirements specified will reduce the statistical accuracy of the results, although it is possible that one or two checks on a few results may seem to show otherwise.

Jan 1, 1950

By K. G. Wikle, W. W. Beaver

A general survey of the mechanical properties of commercially pure beryllium fabricated from powder by vacuum hot pressing and other consolidation methods is presented. The effect of fabrication method, grain size, strain rate, and directionality upon both room and elevated temperature tensile properties is reported. BERYLLIUM metal, in spite of its rather restricted use, has been the object of attention for many researchers in the past half century. However, such work was performed on special experimental lots of metal made in small quantities by a variety of reduction methods. Not until 1946 was there a substantial production of beryllium metal, and not until 1950 was there a steady production of a commercially standard beryllium in the United States. This output was both the result of a requirement of the Atomic Energy Commission for a high grade beryllium of consistent quality and the development of a powder metallurgy process, by the Brush Beryllium Co., known originally as Process Q, which yielded a fine grained beryllium suitable for fabrication. Because this powder metallurgy product, known as QMV, superceded other types of metal made previously and represents the great majority of beryllium in use today, it seems worthwhile to present the results of studies on the mechanical properties of this metal as currently made. To the design engineer and the metallurgist, beryllium has extremely interesting properties. It is as light as magnesium alloys while having a stiffness modulus 40 pct greater than steel and a strength-weight ratio superior to titanium and aluminum alloys and aircraft steels. The melting point is high, 1287°C (2348°F), and it has good corrosion resistance both in air and water. Also, it is highly transparent to X-rays and has good heat and electrical conductivity (electric conductivity is greater than 40 pct of Cu). To the atomic energy program beryllium is considered a valuable material because of its low neutron-capture cross section and high neutron-scattering cross section which make it a good moderator and reflector for the lower velocity neutrons. A major technical difficulty limiting the use of beryllium, especially in structural applications, has been its notch sensitivity and consequent room temperature brittleness. Kaufmann, Gordon, and Lillie1 have reported their work on the mechanical properties of beryllium performed from 1946 to 1950. They studied the room and elevated temperature properties of cast and extruded beryllium and extruded electrolytic flake, Table I. Cast and extruded alloys of 85 to 99 pct Be were tested also. They found that extruded metal developed good strength and appreciable ductility in the extrusion direction and that thermal treatment and alloying provided little improvement in mechanical properties. They concluded that preferred orientation and fine grain size were the means of obtaining optimum tensile properties in beryllium. Other investigators have measured and commented on one of the most striking mechanical properties of beryllium, namely, its abnormally low Poisson's ratio.2 Udy, Shaw, and Boulger3 presented the latest published survey on properties of beryllium but their information is based only on published data available before April 1949 and cites little information on metal fabricated by powder metallurgy

Jan 1, 1955

By JAMES SCULLY

For the last 4 years political leaders have found a new subject on which they can safely generalize wihout creating opposition. That subject is commodity prices. Since the four-fold increase in OPEC crude oil prices, public attention has focussed as never before on the subject of commodity prices. To advocate stabilizing commodity prices is akin to supporting motherhood or peace or better schooling. Everyone gives lip service to the concept that stable commodity prices are desirable. It is easier to state the principle than to achieve it. Prices that are stable in terms of one currency may be clearly unstable in terms of a different currency. This has become a troublesome matter since 1971, when the world's leading trading currencies were set free to float in relation to each other. To illustrate: consider copper prices in the interval between the end of 1974 and the end of 1977. During those 3 years, the copper price in pounds sterling on the London Metal Exchange rose by 25 per cent. During that period, however, in terms of the USA dollar equivalent, the price was unchanged. And during that period, in terms of the German mark equivalent the price shrank by 13 per cent while the Japanese yen equivalent fell by 20 per cent. Thus a price that appears stable in dollars, rose in terms of pounds sterling and fell in terms of marks and yen. Had this result been achieved as a consequence of an international effort to stabilize prices, an American would have said the effort was successful. An Englishman would have said it had failed to prevent a price rise. And a German or a Japanese consumer would have been happy to have covered his copper needs at a lower cost in terms of his own currency.

Jan 1, 1978

By F. W. Bremmer

THE drilling of constantly deeper oil wells has made it imperative that the manufacturer of casing be ever searching for new methods and new materials to meet the increased demands. One phase of this search constitutes the subject matter of the present paper. Starting from the original Drake well in 1859, the depth of wells has advanced by leaps and bounds, until today depths of 6000 to 8000 ft. are common. Conditions point to the necessity for drilling to greater depths, and it is not at all improbable that much of the future oil produc- FIG. 1.-TREND IN DEPTH OF OIL WELLS. tion will be from, wells around 10,000 ft. deep. The trend to deeper wells is nicely illustrated by the curve in Fig. 1.1 The points plotted are the maximum depths attained in the various pools which were at their peak for the years given. It may be of some interest to observe the change that has taken place in the tensile and collapsing stresses over the last 25 years. The pressure at the bottom of a 900-ft. hole, equivalent to the pressure caused by an equal column of water, is only 450 lb. per sq. in. The equivalent

Jan 1, 1930

Jan 1, 1947

Jan 1, 1947

By William E. Ford, Edward Salisbury Dana

THIS Appendix contains a series of tables, more or leas complete, of minerals arranged according to chemical composition or to certain prominent crystallograhic or physical characters. These, it is believed, will be of service not only to the student, but ago to the skilled mineralogist. The type used in the printing of the mineral names indicates their relative importance. Table I is a complete list of the species named in this book arranged fist according to the prominent basic elements which they contain and secondly according to their acid radicals. Table II is of Minerals arranged according to their System of Crystallization The other tablets make no claim to completeness, being limited often to common ah important species. For an exhaustive system of Determinative Tables based particularly upon blowpipe and chemical characters, the student is referred to the work of Professors Brush and Pen- field, mentioned on p. 330.

Jan 1, 1922

By R. B. Schluter, M. M. Fine

Processes for manufacturing prereduced pellets have heretofore required temperatures of 2100°F or higher. Sulfides will accelerate the liquid-phase sintering of metallic iron, yet do not deter the reduction of iron oxides. The sulfides may be introduced as gases to the kiln atmosphere or as solids in the re-ductants. The net result is that well metallized iron pellets with good crushing strength can now be produced at a little over 1800°F. One of the most persistent topics at technical gatherings and in the recent scientific press has been the reduction of iron ore. In May 1960, a symposium on the subject was sponsored by the Electrochemical Society. The proceedings, comprising two dozen papers, were later published.' More recently, in November 1966, a similar gathering took place at Michigan Technological University, Houghton, Mich. The latest meeting was the International Congress on Production and Utilization of Reduced Materials at Evian, France, in May 1967. If the volume of literature, symposia and conferences is a measure of industry concern, then the current interest in reduction must be at a high level. Barrett,2 one of the early pioneers, stated some years ago that "The history of sponge iron has been so discouraging that many men in the iron and steel industry are violently opposed to giving it any further consideration." In spite of the "violent opposition" noted by Barrett, research people in and out of the industry continue to be attracted by the elusive prospect of uncovering a simple, viable means of direct reduction. Wild,3 one of the speakers at Evian, listed no less than 48 direct reduction processes (laboratory, pilot plant and commercial). Some of these were of historical interest only, but many others had resulted from developments within this decade. The previous big thrust into direct reduction occurred under the artificial impetus of a wartime economy (World War 11) and was largely an effort to provide more melting stock without coke ovens and blast furnaces. The present-day inquiry is proceeding at a more leisurely pace and the emphasis is different. For one thing, there is much less anxiety to circumvent the blast furnace. On the contrary, a whole new research endeavor has grown from the discovery that metallized burdens are exceptionally productive.4 Although the search for a melting stock

Jan 1, 1970

By J. L. Huitt, S. R. Darin

The use of a partial monolayer of propping agent to obtain a high flow capacity for a hydraulically induced fracture is discussed. From the results of laboratory work it was shown that a modified form of the Kozeny-Carman relation could be used to describe the flow in the partial monolayer propped fracture. With equations presented in the paper, the density pattern of the propping agent (number of particles per unit of fracture surface) that results in the maximum flow capacity for the fracture can be determined. The maxitnum flow capacity obtained with a partial monolayer is often an order of magnitude greater than the flow capacity obtained in greater width fractures containing multilayers of the propping agent. INTRODUCTION One of the predominant factors controlling the success of a hydraulic fracturing operation is the propping of the fracture. The trend in hydraulic fracturing recently has been an increase in the ratio of propping agent-to-fluid. The primary purpose of this increased ratio is to sustain a propped fracture of greater width. It was shown in a recent study' that for some formations low concentrations of propping agent would result in "closing" or "healing" of the fracture. In some cases, in an effort to insure sufficient propping agent concentration, the fracturing operation is designed to obtain a pack of the propping agent in the fracture. The placing of a pack of propping agent in the fracture provides a fracture of maximum width; however, the width alone does not control the flow capacity of the fracture. The flow capacity is dependent on the permeability of the fracture, as well as the fracture width. Thus, increasing the permeability to obtain larger flow capacities is as important as obtaining a greater width fracture. By increasing the concentration and particle diameter of the propping agent, fractures of sufficient flow capacities are obtainable for effective well stimulation in a number of formations. However, in some of the recovery techniques, the fracture capacity obtained by commonly used practices in fracturing is inadequate. One such recovery technique is gravity drainage via a horizontal fracture placed near the base of the productive zone. For this recovery technique, the fracture capacity desired is usually one to two orders of magnitude greater than the fracture capacity normally obtained in fractures propped with the size of sand commonly used (20-40 mesh). By the use of particles of larger diameter, the permeability of a pack2 is increased; however, even a multilayer pack results in a fracture flow capacity lower than that desired for some formations. For example, a fracture of 1/4-in. width, packed with 8-12 mesh sand of about 2,000 darcies permeability, would result in a fracture flow capacity (permeability X fracture width) of only 40,000 md-ft. If the fracture flow capacity needed is an order of magnitude greater than that cited in the example, an approach different from the formation of a pack in the fracture is needed. One approach is a partial monolayer of large-diameter propping agent. In working with this type of fracture system, it was found that the flow problems were unique to the system; therefore, the study discussed in this paper was made. THEORY AND RELATED STUDIES Previous studies, although related to that described in this paper, have not pertained directly to the flow in a fracture propped with a partial monolayer of propping agent. However, studies such as flow between parallel plates,' flow in packed columns,' fracture flow capacity' and flow in simulated fractures reduce the scope of this flow problem considerably. A fracture propped with a partial monolayer of dropping agent may be considered to be between two extremes — between an open fracture and a bed of particles packed In a conduit of fracture geometry. Thus, it seems appropriate to review the extreme cases.

By J. E. Pollock, W. R. Hicks, E. Camp

IN the oil-refining industry, steel comprises by far the greatest proportion of the materials used in construction work, but with an enormous number of alloy steels and nonferrous alloys available, and a greater knowledge of their properties and corrosion resistance, a substitution first in the "hot spots" and then in locations of moderately severe corrosive conditions will be made as the greater expense can be justified. In new construction work, advantage is taken of the experience already gained and appropriate materials used, whether for high temperatures and pressures demanding additional strength or for corrosive conditions. The locations, however, where equipment in operation constantly requires replacement will soon become evident, as will the necessity for replacement in more resistant materials, if considerable down-time is to be avoided. In what direction and how far to go in the matter of alloys then becomes a question of the highest importance. Obviously, any replacement with more costly material must be justified economically by the promise of longer life, thereby saving both material and installation costs besides the reduction of loss of production. Where the equipment is overcapacity and a regular schedule of cleaning periods is in force, the last item frequently must be ruled out and justification made on the basis of the first two only. Installation of material that will outlast the remainder of the equipment and have no recovery value must also be avoided; this is particularly important in temporary construction or in old equipment that will soon become obsolete. TEST METHODS Either one Of two methods or a combination of both, in the absence of reliable data in similar services, may be adopted to determine to what extent replacement with other, and perhaps more expensive, materials is justified. A unit may be constructed incorporating different metals or alloys so that comparative service may be obtained under the same service conditions; this has been applied in many instances, such as condenser and tank construction, but the opportunities for inspection may be few and

Jan 1, 1935

By Ray Light, Everett M. White

Numerous articles have been written about the coal miner ; he has been compared with brave men who have gone out to conquer some unknown hazard throughout the ages. Now, however, modern mining is no longer something to be avoided, but a vocation that anyone can be proud of, with remuneration equal to or above that of almost any industry. A concerted effort is being made each day by both the operators of most mines as well as the state and federal inspectors to see that coal mines are as safe or safer than work places in any other industry. However, it is true that mine fires and explosions have occurred in the mining industry since its inception. One of the earliest accurate references to such an occurrence is found in the transactions of the Royal Society of London. In the Colliery Managers' Handbook, 1898, Caleb Pamely writes of an explosion that occurred at Fatfield, England in August 1708, resulting in the deaths of 69 persons. He states: "Three of them, viz, two men and a woman, were blown quite up from the bottom of the shaft, fifty-seven fathoms deep, into the air, to a considerable distance from the mouth of the pit." It is interesting to note that women were employed as miners in England during that period. In the United States, the first record of coal mined was in 1702 by the Jamestown colonists. In 1786, about 20 years after Pittsburgh, PA was first settled, a charter was granted by William Penn to mine coal on the banks of the Monongahela River. Then in 1803, the first important coal company, the Lehigh Coal Co., was established. From this beginning, the mining industry continued to grow in importance and the first state mining law was formulated in 1870. The Pennsylvania state mining law was followed in 1873 by Ohio's, and in 1876 by Maryland's. A mine explosion at Avondale, PA in 1869 stimulated state legislatures to formulate these early laws. In 1907 near the town of Fairmont, WV, there were, within three days, two explosions resulting in a total of 597

Jan 1, 1981

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

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

Jan 1, 1960

By Paul Merica

ALTHOUGH nickel was discovered and isolated as early as 1750 and its valuable properties recognized, many years passed before it was used commercially for wire, sheet, rods, etc., in the pure form. This was due partly to its high cost at that time and partly to the fact that it was not possible to refine and cast nickel into ingots sufficiently malleable to be amenable to the usual forging, rolling, or drawing processes. So remarkable was this fact, and so different from the experience at that time with metals such as copper and iron, that it has left its impress on the no-menclature within the nickel industry. To this day, furnace-cast nickel produced in such a manner as to be suitable for rolling and forging is called malleable nickel to distinguish it from the ordinary pig and shot nickel of commerce. In 1878, the firm of Jos. Wharton, of Philadelphia (which later became The American Nickel Works, a constituent of The International Nickel Co.) exhibited at the Paris Exhibition specimens of rolled pure nickel strip and of drawn nickel wire. About this time, there was considerable activity in the study of the refining of nickel and several methods were described, some of which were patented, for the production of furnace-cast malleable nickel including the use of manganese (Boed-dicker,1 Selve and Lotter2), the use of potassium permanganate (Bernsdorfer Metallwarenfabrik3) and the use of phosphorus (Garnier4). By far the most efficient method was discovered by Th. Fleitmann in 1879;5 it consisted in adding to the molten nickel, just before pouring the castings, from 0.05 to 0.125 per cent. of metallic magnesium. This soon became the recognized final malleableizing treatment for furnace-cast nickel.

Jan 1, 1925

By D. B. Rushmore, K. A. Pauly

Of primary importance in mine-installations is the hoist, which has a very direct bearing on the successful operation of a mine. Conditions vary greatly with different mines, and especially in different localities. Such factors as depth, incline, the number of levels, permissible or desirable speeds, conditions of ore, etc., are always more or less special in each case. Veins of ore are never exactly duplicated, and the nature of the ground through which shafts are sunk may considerably modify permissible values. As mining-laws are made by the different States, they necessarily vary somewhat, and, even when not fully observed, they introduce factors which qualify the conditions of hoisting men and ore. The amount of timbering required is often of importance as relating to hoisting-conditions. Methods of loading ore affect the time required, as also does the question of the use of cars or skips. Safety-precautions must be very carefully considered, and the number of men in each mine, the number of compartments, and often the method of removing water from the mine, must have careful consideration. While a general discussion of the subject of hoisting is possible, most cases are entirely special, and can be considered only in connection with the peculiar conditions pertaining to that particular installation. The cost of installation of the hoisting-plant may be an appreciable amount, while the cost of raising the ore may be but a small part of the total operating-charge. In many cases, however, the output of the mine is limited by the capacity or the hoist, and the latter thus becomes of the first importance.

Jan 1, 1911

By Arvid E. Anderson, Frank K. Cameron

The weathering of copper-bearing ores with the formation of a water soluble salt and the recovery of the metal by leaching and evaporation precipitation, are processes long known, which have at various times been utilized with more or less commercial success. It is commonly assumed that the technical principles involved are quite simple and their application to a particular case easy. If these assumptions were true, we should anticipate a long list of uniformly successful leaching operations, which is not the case, and one would be justified only in calling attention to either unique or peculiar features of any particular enterprise; whereas, in studying the problems of the recovery of copper from the old workings of the Ohio Copper Co. in the light of available descriptions of other leaching projects, we have not found the assistance hoped for to guide us to the best realization of our own opportunities. It appears desirable, therefore, to call attention to these guiding principles, together with a description of the facts of accomplishment. Justification lies in the fact that the leaching and precipitation of copper at the Ohio Copper Co. mine in Bingham Canyon, Utah, is successful. This success is measured by an average monthly production of 600,000 Ib. of copper at an average operating cost, to date, of 3.85 cents per pound at the company's workings, or 6.32 cents per pound after paying shipping and smelter charges on the finished copper. A total of 17,076,099 Ib. of copper had been shipped to the smelter from the beginning of operations, August, 1922, to April 1, 1925. Probably these results can be bettered with further study and realization of the factors involved and the devising of methods of meeting them. It is now an assured fact that the enterprise will have a relatively long and continuously profitable life and that its reserves will not, nor cannot, be suddenly and permanently depleted. It is particularly noteworthy that the financing of this enterprise has been entirely from its earnings. The few hundred dollars necessary for the first experiments and production were obtained by the sale of used, and no longer needed, equipment from a mill belonging to the company; and all funds since required throughout the growth and development of the enterprise, from a few troughs with a production of 2000

Jan 1, 1926

By J. L. Tokich, A. R. Troiano

INTRODUCTION SINCE 1921, when Hull' discovered that cobalt can exist in the face-centered cubic and hexagonal close-packed modifications, the transitions that occur in cobalt have been extensively studied. It is generally agreed that on heating the hexagonal lattice changes to the cubic structure at temperatures ranging from 400 to 500°C although considerable doubt exists as to the exact temperature. Data concerning the temperature of the transformation on cooling are much less concordant and their interpretation has not been satisfactory. The study is further complicated by the fact that many investigators have reported the existence of a high temperature allotropic change in the range 850 to 1020°C, at which the cubic lattice reverts to the hexagonal modification. The transition on cooling, which has been reported as occurring at various temperatures from approximately 400 to 100°C, is of particular interest. Troiano and Greninger2 have recently suggested and considered the possibility of allotropic transformations occurring in pure metals by a shear-type, diffusionless (martensite) transformation. The case of cobalt was specifically discussed and certain observations of previous investigators evaluated in terms of this type of transformation. Table 1 briefly outlines the methods and results of previous investigators of the transformation temperatures of cobalt. MATERIALS AND METHODS The major portion of this investigation was performed with cobalt sheet containing a total of 0.2 pct impurities with carbon present to the extent of 0.1 pct. After melting in an induction furnace under an atmosphere of hydrogen, the carbon content analyzed 0.03 pct. Some observations were repeated with hydrogen reduced cobalt compresses analyzing 99.9 pct pure. No significant variations in results were observed employing the as-received sheet, the remelted stock, or the cobalt compresses. Filings for X ray diffraction analysis were sealed in evacuated glass ampoules. Pyrex glass tubing was used for temperatures below 600°C and for higher temperatures clear fused quartz was satisfactory. After appropriate heat treatment at various temperatures, the specimen ampoules were furnace cooled, air cooled or quenched by crushing under distilled water. This allowed a range of cooling velocities from less than one degree C per sec to greater than 1,000°C per sec. X ray diffraction patterns were taken with a Debye camera and filtered characteristic cobalt K-alpha radiation. The proportion of the existing phases was roughly approximated by visual examina-

Jan 1, 1948