Search Documents

By C. R. Austin

IN a recent paper1 the authors presented information on a refinement of the Rohn type of creep test with data on pure iron that exemplified the behavior of the apparatus. The present paper extends that work to nickel and cobalt and to the examination of the comparative high-temperature properties of two widely used commercial alloys. Careful attention has been given to the effect of plastic deformation in decreas-ing creep rate, using the elementary metals iron, nickel and cobalt for purposes of analysis. In any, endeavor to develop new materials for high-temperature service one soon encounters a real problem as to the sort of test to be employed in evaluating the commercial possibilities of the alloys. At one time it was considered satisfactory to determine the tensile strengths at elevated temperatures and to use these values as a criterion for the commercial application of the alloys. More recently the proportional limit has been used as a means of classification. Data obtained from a form of bend test has also shown promise as providing a "merit index" of high-temperature serviceability.2 Koerber and Pomp3 state that since the influence of testing time is small, the high-temperature yield point of steel furnishes sufficiently reliable and concordant values up to about 350° C. (and a maximum of

Jan 1, 1934

By Ernest J. Stocking

ENGINEERS are the key men in our war program today. Upon the technical knowledge and skill of the engineer and upon his administrative and executive abilities rests the entire success for the production of vital materials of the war. Naturally the work load of the engineering examining unit of the U. S. Civil Service Commission has increased greatly since our active participation in the war. At present, over 550 separate requests for certification of eligibles are received by the engineering unit per week. These represent more than a fourth of the total requests received for personnel by the Commission's central office at Washington and represent a recruitment work load of three to four times that carried by the whole Commission previous to January 1940. These requests represent a minimum of a thousand vacancies to be filled each week, while an average week will produce, at present, approximately 1400 vacancies and a weekly maximum may approach well over 2000 vacancies.

Jan 1, 1942

By R. G. Webber, F. C. Langenberg

During the course of some magnetic investigations which the authors have under way, six bars of 0.43-carbon steel were tested, a permeameter designed after the Hopkinson yoke type being used. The results obtained were of some interest and although far from complete serve at least to show the necessity for a careful investigation of the previous history of the samples under study as well as the chemical composition. A steel of given chemical composition may assume a great variety of structures, depending on its treatment. Professor Sauveur has devised a very clear and effective means of illustrating this point. The accompanying microphotographs show some of the possible structures assumed by a 0.30 carbon steel (Fig. 1). It is now a well-established fact that a structural change is accompanied by changes in the tensile strength, elastic limit, hardness, etc., and it seems reasonable to assume also, a change in the magnetic properties. Six bars of a 0.43-carbon steel were used, all the bars being taken from the same rod and treated as follows: Bar 1. Heated to 1,100° and cooled in the furnace. Bar 2. Heated to 1,000° and cooled in the furnace. Bar 3. Heated to 900° and cooled in the furnace. Bar 4. Heated to 1,000° and cooled in air. Bar 5. Heated to 900° and cooled in air. Bar 6. Untreated. The bars were then turned to 13 mm. diameter and tested by the Hopkinson yoke method. After testing, three specimens were taken from each bar, one from each end and one from the middle. The homogeneity of the bars was tested in this manner and in no instance could any difference in structure in the three specimens1 be detected. Bars 1 to 3 inclusive are pearlitic in structure. The white areas are ferrite (iron with certain impurities in solution) and the dark areas pearl-

Jan 1, 1915

By William P. Shinn

Jan 1, 1881

By M. L. Requa

In the fall of 1910, the Nevada Petroleum Co., operating in the Coal-inga field in California, determined to drill a number of wells with rotary tools, in order to prove conclusively the relative value of the rotary as compared with the standard rig. At that time, the rotary was but little known in California and its proposed introduction met with considerable criticism on the part of the operators and quiet opposition among the standard drilling crews. There were few men available who were competent to handle a rotary outfit, and these few had had but little experience in California fields. Machines as then built were much inferior to those now used, being lighter in construction and of a poorer quality of material. The shells encountered at depths between 1,700 and 2,000 ft. seemed to be too hard to permit of successful drilling, and at these depths the rig was changed over to standard tools and by them completed. Because of the heavy depreciation, the time lost in converting from rotary to standard, and the comparatively small profit, it was concluded that unless in the future there was some material improvement in rotary rigs, nothing would be gained by drilling with rotary tools upon this property. Little or no drilling has been done upon the property since that time, but in the meantime a large number of men have been trained in the use of the rotary; in fact, many standard-tool men have abandoned standard drilling and, starting in as roustabouts, have become thoroughly competent rotary operators. The improvements in the machinery have been such as to remove many of the objections and the rotary drilling of to-day is in every way superior to that of 1910. In contrast, a well drilled recently by the Kern Trading & Oil Co., in the east side Coalinga field may be cited. The first 2,500 ft. was drilled in 24 days and it is confidently expected that the water string will be set with a rotary at 3,400 ft.—a record obviously far beyond that made in 1910 by the Nevada Petroleum Co. The records herewith are published with the hope that some one having more recent data will publish them so that comparison may be

Jan 1, 1915

By A. Steiner, K. L. Komarek

Activities of aluminum in solid Ni-A1 alloys have been determined between 20 and 60 at. pet Al and 1200" and 1400°K by an isopiestic method in which nickel specimens, heated in a temperature gradient, are equilibrated with aluminum vabor in a closed all-alumina system. The activity of aluminum shows a strong negative deviation from Raoult's law at low concentrations but increases by three orders of magnitude within the ß(NiAl) phase. The partial molar enthalpy and entropy of mixing are negative. Using Wagner and Schottky's theory of ordered compounds, a degree of disorder of 4 x 10 -4 for NiAl and 1.25 X 10-2 for FeAl has been calculated THE Ni-A1 system has been studied by a great number of investigators, and the results, as far as the phase diagram is concerned, have been compiled by Hansen.1 The phase boundaries from 0 to 50 at. pet Ni are well-established. At higher nickel contents the boundaries are still in dispute and an additional phase, A12Ni3, has been reported.' The phase diagram is dominated by a very stable high-melting compound, NiA1, with a relatively wide range of homogeneity. Heats of formation of solid alloys have been determined calorimetrically by Oelsen and Middel3 from 20 to 95 at. pet Ni and by Kubaschewski4 from 25 to 80 at. pet Ni. According to the most recent compilation5 no other thermodynamic investigations have been reported for the Ni-A1 system. Due to the corrosive nature and the low vapor pressure of aluminum, a method has been employed for determining activities of aluminum which was previously developed for the Fe-A1 system.= Nickel specimens, heated in a closed evacuated alumina system in a temperature gradient, were equilibrated with aluminum vapor from a source within the system kept at constant temperature. After complete equilibration the specimens were analyzed and activities calculated from the known vapor pressure of aluminum. APPARATUS AND EXPERIMENTAL PROCEDURE Materials. The nickel specimens were made from wafers of electrolytic nickel (International Nickel Corp.) of 99.99 pet purity which were rolled to a 0.001-in.-thick foil by Driver-Harris Co. and to a 0.005-in.-thick sheet in our laboratory. The aluminum (Aluminum Corp. of America) had a purity of 99.99+ pct. The alumina tubes and crucibles were made of impervious recrystallized alumina with an alumina content of 99.7 pet (Triangle RR, Mor-ganite Inc.). Experimental Procedure. Annular specimens were punched from the sheet, the punching burrs removed, and the specimens degreased in carbon tetrachloride and acetone and weighed on a micro-balance to within an accuracy of ±0.01 mg. The specimens were positioned with alumina spacers along an alumina tube, and the positions measured. Aluminum metal was machined into cylindrical shape, and placed into an alumina crucible. The tube with the specimens was then inserted into a hole drilled into the aluminum metal. An alumina tube with its closed end at the top was slipped over the specimens so that its lower end fitted snugly into the alumina crucible. The assembled reaction tube was inserted into a mullite tube with a water-cooled brass head which had an opening for a quartz thermocouple protection tube and a metal-to-glass connection to a conventional vacuum system. A Pt-Pt 10 pet Rh thermocouple could be raised and lowered in the quartz tube which was placed along the outside of the alumina reaction tube. The mullite tube was heated by two separately controlled resistance-tube furnaces so that in the experimental temperature range an over-all temperature gradient of approximately 150o to 250°C could be imposed on the reaction tube. The position of the mullite tube was adjusted so that the surface of the aluminum metal was always at the temperature minimum. The reaction tube was thoroughly evacuated before and during slowly heating the assembly up to the melting point of aluminum. A pressure of less than 2 µ (Hg) was maintained during an experiment. Once the aluminum had melted, it isolated the contents of the alumina tube from the surroundings. Several times during an experiment the temperature gradient was carefully measured. An experiment lasted from 3 to 6 weeks and it was terminated by air cooling the evacuated mullite tube. For further details of the experimental procedure the paper on the Fe-A1 system6 should be consulted.

Jan 1, 1964

By Robert B. Fulton

Commercially, celestite (SrSO,) is the only significant strontium mineral. Among other strontium-bearing minerals, only strontianite (SrCO,) occurs commonly; however, it is not an item of commerce. The principal production of celestite is in England, Mexico, and Spain. New production is now coming on stream in Canada. Consumption is mainly in the United States. Lesser quantities are consumed in Japan and Europe. Main uses are for the manufacture of strontium carbonate and nitrate. The carbonate is used in glass for TV tube face plates and in ferrites for magnets. The nitrate is used in pyrotechnics to which it imparts a characteristic brilliant red color, mainly in safety flares. Minor amounts of strontium compounds are used in electrolytic zinc manufacturing and very small quantities in greases, ceramics, soaps, alloys, and pharmaceuticals. Specifications and Prices Typical celestite specifications for the carbonate and nitrate markets are as follows: [ ] Celestite currently shipped from Mexico for carbonate manufacture tends to be slightly better than these industry specifications, assaying about 92-93% SrSO, with less than 1% BaSO, but it is generally below the 95% minimum required for nitrate production. Contract prices for celestite are approximately $32-34 per st at U.S. Port of Entry in 50 to 60-ton carload lots for Mexican material. Spot prices are generally reported as low as $20 per st but are for minor volumes. A recent sale of surplus from the U.S. stockpiles, announced by the General Service Administration (GSA), was 4005 st sold to Du Pont for $140- 455 or $35.07 per st. British celestite, ground, washed, and graded, 95% SrSO, bulk, ex- works, 240 mesh, is quoted at £ 28.75 per mt in British trade journals, and a recent figure quoted for crushed lump material was $36.00 per st f.0.b. vessel Bristol Channel port (1973). Specifications of manufactured carbonate made from celestite and sold in two grades, one to the glass industry, the other to the electronic industry for ferrites, are given in [Table 1]

Jan 1, 1975

Discussion of a paper of S. S. Rummy and W. F. SCHWEDES, presented at the Pittsburgh meeting, October, 1914, and printed in Bulletin No. 94, October, 1914, pp. 2613 to 2635. K. A. PAULY, Schenectady, N. Y.-I have seen this installation and I wish all those interested in the question of electricity as a mine pumping agent could see it. It is not only a model for mine installation, but might well serve as a model for any electrically driven pumping plant. I think I am correct in saying that the pumps are the largest electrically operated centrifugal pumps in mine service in America. I talked with Mr. Rumsey in Duluth just before coming here, and he told me that the actual tests of the equipment as installed checked very closely with the shop tests; that the water delivered by the pumps was slightly in excess of the guarantee, something like 3 or 4 per cent., and that no troubles except of a very minor nature had been experienced with the installation from the start. One point which has been brought out by Mr. Rumsey, and by others who have looked into this question, is the marked saving which' can be made by the application of electricity to pumps, especially to the main sump pumps. The pumps are always located a long distance from the boiler plant and the losses in the steam mains are large. While many of the steam pumps are of a very high grade, yet the tests seemed to indicate that the steam consumption is extremely large. The reduction in operating cost of one small installation which I. have in mind pumping against a head of approximately 2,000 ft.-which by the way was a reciprocating pump-reduced the pumping cost to the neighborhood of one-fifth of the previous steam cost. . The high steam cost was probably due to leakage in the engine and the loss in transmission in the mine, the pumps being located almost half a, mile from the boiler plant.

Jan 4, 1915

By F. W. Lee

Historical-From the beginning of time, all ingenuity of mankind has been concentrated upon the methods of finding gold and unusual deposits in the earth. An illustration (Fig. 1) from the old treatise by Agricola, "De Re Metallica," published in 1580, will serve to show the im-plicit faith of that generation in divining methods. However, it was not until 1920 that real progress was made in prospecting by using the latest advances of the physical sciences. The public interest was stimulated by the successes of these methods on the part of commercial oper-ators, and governmental agencies received many requests for information concerning their relia-bility. There were also, in the late 1920's.high- pressure mine-promotion schemes which used geophysical methods in a very questionable manner, symbolized in Figure 2 as of 1928 by an elec-trified forked stick. Authoritative information concerning such practices for public protection was needed to curb such notorious undertakings. Dr. Scott Turner, then Director of the United States Bureau of Mines, thoroughly understood the situation and was first in the governmental de-partments to recognize the possible value of a study of modern prospecting methods. The Bureau of Mines began this investigation by employing Drs. A. S. Eve and D. A. Keys of McGill University for short periods in the summer in 1927. Their first publication [see 1 of "References" at end of paper] served to illustrate the fundamental scientific principles which underlie geophysical prospecting. This was followed by a second publication [21 giving the results of field-tests. In the light of the rapid improvements during the intervening ten years, these two papers take a historical position. Later a full-time position under Civil Service was planned by the Bureau of Mines for con-tinuous investigations and research concerning geophysics and its applications to prospecting. It was Turner's idea that. since the oil-industry had been making very rapid progress with good results, if mineral mining could also benefit to the same degree, it would be of great help to that industry.

Jan 1, 1940

By W. J. Taylor

IN making heating gas with anthracite coal for roasting ore during the past few years, I hare tried many forms of gas generators. So far, the most successful and satisfactory one has been what we call a fluxing producer, which is simply a small cupola or blast furnace, in which we charge with the coal, say, 30 or 40 per cent. of basic blast-furnace cinder, to unite, when melted, with the ash or earthy matter in the coal, and carry it off as cinder. The producer we have in use at Chester, N. J., has pore of the lines of a blast furnace than a cupola, the hearth being 24 inches diameter and 24 inches high. It then enlarges on an angle of about 25 degrees from a perpendicular to 4 feet, and then is drawn into 3 feet on top ; total height, 12 feet. We use one water coil-tuyere 12 inches above the bottom, and blow through a 11/2-inch nozzle. The depth of coal above the tuyere averages about 6 feet. The producer. is blown with

Jan 1, 1881

By R. K. Buhr, H. Thresh, M. Bergeron, F. Weinberg

The microsegregation of nickel and chromium in directionally solidified AISI 4340 steel castings has been measured using electron probe microanalysis. Minimum concentrations were observed to occur at the center of the dendrite stalks, as reported previously. However, the position of the maximum concentrations could not be determined from the dendrite configuration. An etching technique has been developed which shows the position of maximum concentration. Measurements were made of the distribution of nickel and chromium in the dendritic structure. The ratio of maximum to minimum concentration was determined as a function of primary dendrite arm spacing for both as-cast and partially homogenized materials. The results are compared with observations reported in the literatuve. A S part of an investigation of solute segregation in directionally solidified AISI 4340 steel casting, electron probe microanalysis was used to measure the distribution of nickel and chromium in the dendritically segregated material. This complemented the observations on the segregation of radioactive phosphorus obtained by autoradiographic techniques in the same castings.' Kattamis and I?lemings2 have reported similar measurements, using electron probe microanalysis, on dendritically segregated AISI 4340 steels. They found minimum solute concentrations occurred at the center of dendrites, maximum concentrations occurred in the center of interdendritic regions, for symmetrically oriented dendrites, and a regular variation of concentration within dendrite arms. The ratio of maximum to minimum concentration was found to be essentially independent of position in the castings, except near the chill surface where it was somewhat higher. Assuming complete diffusion in the liquid and no diffusion in the solid during freezing, they considered that isoconcentration curves in the steel were homothetic. As a result, isoconcentration curves of the various elements, contour surfaces of dendrites produced by isothermal-transformation studies, and the contour of the solid-liquid interface would all be similar, and could be superimposed by a uniform expansion or contraction of the contours. Preliminary results of the present investigation suggested that isoconcentration curves were not homothetic. It was also evident that points of maximum concentration could not be predicted from the dendrite configuration. Since the ratio of maximum to minimum concentration appeared to be an important parameter in defining the overall segregation in a casting, other techniques for determining the point of maximum concentration were investigated. In addition the overall solute distribution associated with the dendritic structure was examined for both nickel and chromium, and the consistency of the distribution for neighboring dendrites was determined. METHOD Fifty-pound heats of AISI 4340 steel were cast in a manner similar to that used by Flemings et al3 with a water-cooled copper base plate and exothermic sides and top. The nominal composition of the material was C, 0.41 pct; Mn, 0.66; Si, 0.35; S, 0.012; P, 0.010; Ni, 1.88; Cr, 0.95; Mo, 0.28. The steel solidified directionally from the chill surface, with a dendritic structure which increased in dendrite arm spacing with increased distance from the chill. Results of the general investigation of the cast structure and segregation of radioactive phosphorus in these castings have been reported elsewhere.' For the present measurements, sections were cut from the casting at several distances from the chill surface. The sections were subsequently heat-treated, mounted, and then polished on a plane perpendicular to the general freezing direction of the casting. Electron probe microanalysis was carried out with the JEOL-JXA3 microprobe using a voltage of 25 kev and beam current of 0.15 µa. The take-off angle is 22 deg. Quartz crystals were used in the spectrometers and measurements made for Ka radiation from both nickel and chromium simultaneously. A thin layer of carbon was deposited on all specimen surfaces prior to examination in the microprobe. Early measurements were made on polished surfaces, with indentation marks produced by a hardness tester to indicate the area of interest. It was found desirable to use etched surfaces, as opposed to polished surfaces, to reduce sample preparation time and more readily relate the microprobe scan to the structure. To determine if this could be done, without introducing significant errors, a series of measurements were made on polished and etched surfaces of the same specimen. Both polished and etched surfaces produced similar results within normal scatter as shown in the observations. Subsequent measurements were then made on etched surfaces. Measurements with the microprobe analyzer were made by point counting, for periods of 100 sec, at 10-µ intervals. Ten-second counts were made on pure nickel and chromium standards, incorporated in the specimen mount before and after each set of measurements. The results were adjusted for background, then corrected for dead time using the expression:

Jan 1, 1969

By AIME AIME

THE second session on geophysical prospecting at the February meeting of the Institute was a discussion of the mining law and the bearing of the new method of search on location of claims and assessment work thereon. Allen H. Rogers was chairman of the meeting, which he opened by reviewing the present law and the proposed changes. W. R. Ingalls commented (by letter) on the Arentz bill, as introduced into the House of Representatives in 1921 and the need for revision of the present mining law. L. W. Douglas explained (by letter) the bill that he introduced and which has been passed by the House. SAMUEL S. ARENTZ, Nevada: It is my opinion that if the American Institute of Mining and Metallurgical Engineers is to sell this proposition to the people in the West, they have to sell it to the lawyers, because, after all, they are heard loudly when it comes to speaking in Congress. One man tells the other, "This thing is a vicious piece of legislation"; it might not be, but they will pass it on if it affects them. If the Institute would impress on the people affected that we need a re-codification of the mining law and that such is necessary along certain lines; that things have changed during the past decade or two, so today instead of doing our prospecting alone through the sinking of a shaft, through a discovery that may be seen, we are now moving on to more modern means of discovery through geophysics, through the churn-drill, through geology, through geological inference, I think we could get somewhere.

Jan 1, 1929

By H. O. Hofman

PAGE Part I. Decomposition OF Zinc Sulphate by Heating in Air, . 811 I. Introduction............ 811 II. Zinc Sulphate Used,..814 III. Fumes and Pyrometers,........ 816 IV. Heating Zinc Sulphate—Dehydration,...... 817 V. Heating Zine Sulphate—Decomposition...818 (a.) Beginning of Decomposition..818 (b.) Rapidity of Decomposition,..819 (c.) End of Decomposition..823 (d.) Retardations in Heating.-Curve,..825 (e.) Formation of Basic Salts,..826 Part II. Decomposition OF Zinc Sulphate by Heating with Carbon (Reducing Roast), .830 I. Introduction,........... 830 II. Experiments and Results ,.........832 III. Summay,........... 834 Part 111. Formation of Zinc Sulphate by Roasting,... 834 I. Introduction,........... 834 IT. Description of Blende,......... 836 III. Outline of Operations,.........838 IV. Details of Experiments.......... 839 1. Decrepitation,.......... 839 2. IgnitionPoint,....839 3. Sulphatizing-Roast of Joplin Blende..840 4. Sdphatizing-Roast of Warren Blemde ,..843 5. Sulphatizing-Roast with Addition of Pyrite...848 6. Summary of Sulphutizng-Roasts,....... 854 Part IV. Appendix : Formation of Zinc Ferrate...856 Part I. Decomposition of Zinc Sulphate by Heating in Air. I. Introduction. With the exception of lead sulphate. all common metallic

Jan 1, 1905

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'C.; 2.4 at 900'C.; 1.7 at 800'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 D. A. Kraai, S. Floreen

The effect of 1 to 50 ppm S on the ductility of nickel at 800° to 1400°F was studied. Results at each temperature showed a decrease in the reduction of area from approximately 95 to 5 pet over the sulfur range studied. Ductility varied with grain size, but only to a minor extent relative to the sulfiw effect. The effects of sulfur were completely offset by the addition of small amounts of magnesium. The results indicate that the "hot-short" loss in ductility is not an inherent property of nickel. Some possible mechanisms which cause the loss in ductility are described. MANY metals or alloys that normally possess high ductility exhibit a ductility loss at intermediate temperatures. This loss in ductility is often called "hot-shortness". Numerous examples of this phenomenon have been reported in the literature. Much of this work has been reviewed by McLean1 and by Rhines and Wray.2 To date there is no fully satisfactory explanation of the cause of this intermediate-temperature hot-shortness. It is generally recognized that impurities, and particularly impurities that form low-melting phases, can cause embrittlement. Examples of hot-shortness have been reported, however, where there were no obvious impurities present which would lower the ductility. Thus there has been some basis for believing that hot-shortness is an inherent property, and that even the purest metal would display a hot-short loss in ductility. This latter hypothesis was recently put forward by Rhines and wray2 based on studies of nickel and nickel alloys. In the discussion of this paper, however, Guard noted that high-purity nickel showed no hot-shortness.3 Thus there is reason to doubt whether pure nickel, or by inference any other pure metal, will inherently exhibit hot-shortness. The present work was initiated to determine the extent to which hot ductility was sensitive to very small amounts of an impurity element. If it could be demonstrated that hot-shortness could be induced by only minor amounts of an impurity, then it might be argued that hot-shortness in general is an impurity effect, and not a fundamental property of pure metals. The particular impurity studied was sulfur in nickel. The deleterious effects of sulfur are well- known. It is also well-known, and will be shown below, that additions of magnesium will render sulfur innocuous. When no such refining agents are added, however, the Ni-S system is a very useful one for studying the influence of small amounts of impurities. EXPERIMENTAL PROCEDURE Two heats containing -24 ppm S were vacuum-melted and small amounts of magnesium were then added under an argon atmosphere. These alloys were used to show the effectiveness of the normal magnesium treatment in overcoming the influence of sulfur. A second series of alloys with a sulfur range of 1 to 50 ppm was then prepared by vacuum melting nickel in alumina crucibles. No elements, such as magnesium, which tend to combine with sulfur were added. The higher sulfur contents were attained by adding nickel sulfide. Lower sulfur contents were prepared using a method in which the melt was oxidized under vacuum to produce the reaction S + 2O = SO2 These heats were subsequently deoxidized with carbon. Ten- to twenty-pound ingots were cast of all of the alloys studied. The compositions are given in Table I. The ingots were forged and hot-rolled to 3/4-in. bar. They were then annealed at either 2000" or 1600°F to produce different grain sizes. One-quarter-in.-diam tensile specimens were machined from the bars. These were tested at 800°, 1000o, 1200°, and 1400°F. The specimens were held at temperature approximately 45 min before testing. The strain rates were 0.005 min-1 to yielding, and 0.05 min-' after yielding. No extensometers or gage marks were placed on the specimens because the higher sulfur heats tended to fracture at the knife-edge indentations or gage marks. The properties measured were ultimate tensile strength and reduction of area. The analytical technique for determining sulfur at low levels was that developed by Burke and Davis.4 They reported a standard deviation of 1 ppm at an average sulfur level of 4 ppm in NBS standards. A standard deviation of 3 ppm is probably more realistic for the alloys used in this investigation considering the possibility of some segregation in the ingots. RESULTS A summary of the tensile results is given in Table I. As shown in the table, both heats to which

Jan 1, 1964

By J. MURRAY RIDDLELL

AN increase of 18 per cent in the production and consumption of all metals last year was readily met by the mines, but more than an average amount of development work was made necessary. Mining methods were improved appreciably; open-pit operations ad¬vanced more than underground practice: and the transportation phase of mining progressed to a greater extent than the other related functions. A new belt-conveyor system of mining was placed in operation at the Spruce open-pit iron ore mine at Eveleth, Minn. The gathering portion of the belt system was installed beneath the surface of the open pit, following closely the bottom rock, in especially provided drifts; beyond it inclined upward to the surface and finally discharged into a 500-ton shipping pocket. Length of the belt was 4500 ft. net vertical lift 386 ft. and capacity 750 long tons per hour. The mined ore found its way to the belt through one of three vertical raises, whose horizontal section was 10 by 10 ft. Each raise was equipped with a grizzly, crusher, pan-type feeder, and auxiliary equipment. Transportation of the ore from the working faces of the pit was accomplished as follows: (1) Two raises were equipped with tower and anchor stations, 3-cu.yd. drag scrapers, and related power units; (2) the remaining raise was provided with electrically driven power shovels and 20-ton trucks mounted on pneumatic tires. This installation has entirely replaced railway pit haulage and partly eliminated power shovels. In a similar

Jan 1, 1938

By F. F. Aplan

INTRODUCTION Coal is a solid combustible mineral substance resulting from the alteration of vegetable matter largely in the absence of air. It occurs in nature with varying percentages of mineral matter associated with and incorporated into the coalified material. If the amount of this inorganic mineral matter is sufficiently small, and if selective mining can be practiced so as to avoid the incorporation of ash- bearing material from adjacent strata and/or parting seams, the coal can be used as-mined. Otherwise, it must be given a preparation treatment. In 1980 the bulk of the approximately 525 coal preparation plants were located in the eastern half of the U.S., largely in the Appalachian and to a lesser extent in the midwest coal fields (1). Only 17 of these preparation plants were located in the west; these were in Colorado, New Mexico, Utah, Washington and Wyoming. In the past, however, a great many more preparation plants were operated in these and other western states. The upsurge in both the domestic and world- wide demand for quality coking and steam coal will certainly lead to an increase in the number of preparation plants in the west. In fact, there has been a massive development of coal mines and their associated preparation plants across our northern border in Alberta and British Columbia, largely to serve the export coking and steam coal market. Most of the tremendous increase in newly-mined coal in the western U.S. has come from thick seams of inherently low-sulfur, low- ash coal, easy to mine selectively without significant contamination with ash-forming minerals and requiring no preparation. Because of

Jan 1, 1983

The sixty-fifth Congress created a commission on classification and standardization of wages of Government employees consisting of three members of the Senate and three ex-members of the House of Representatives: The Chairman of the National Service Committee has been notified orally by the Vice-chairman that when said Commission reaches the consideration of engineers' salaries in the Government service, request will be made for assistance of Engineering Council. As it is probable that this request will be received prior to the June meeting of Council, it is recommended that action be authorized concerning the appointment of a suitable committee of Council to undertake this work.

Jan 6, 1919

By C. G. Wilson

DURING the course of some experiments on the plastic deformation of gallium a standard stereo-graphic projection was prepared with (001) at the center and it was felt that this might be useful to others working with single crystals of gallium. The stereogram, given in Fig. 1, was made using the following crystallographic data (Bradley, 1935):

Jan 1, 1962

By Charles B. Henderson

DESPITE the loss, by enemy conquest, of a high percentage of our normal sources of supply for tin, the position of this important metal is easier today than that of rubber and a long list of other strategic materials, many of which are produced in this country. Actually, there is no shortage of tin for essential war purposes, owing to a strict control of its use, to increasing considerably the amount of secondary tin available, and to the foresight of the Government in authorizing the Reconstruction Finance Corp., as early as June, 1940, to acquire and produce certain critical and strategic materials of which tin was one of the most important. The construction of the Longhorn Smelter on the Gulf Coast in Texas is an important part of this program.

Jan 1, 1943