Search Documents

By L. W. Page

PrEvious to the introduction of the motor vehicle the broken stone or macadam' road met the conditions of rural horse-drawn traffic better than any other type of road, but under fast motor traffic it has been proved to be quite unsatisfactory, and necessitates high maintenance charges. Such a road depends for its success upon the fact that the rock dust fills the voids between the stones and acts as a cement or binder. Under ideal conditions it should be constructed of rock so suited to the volume and character of horse traffic that only enough fine dust is worn from the stones of which the road is composed to take the place of that carried off by wind and rain; and when these conditions are met, the fine dust resulting from the wear of traffic forms with the stone a smooth, impervious shell, shedding the surface water and protecting the foundation. With increase in the number and speed of motor vehicles, however, it was soon found that the cost of maintenance also increased, until at the present day highway engineers consider the old method of constructing and maintaining broken-stone roads increasingly inadequate, and are introducing every known type of binding material other than rock dust to cement the stone together. Among the most prominent types of products in use are those produced from our various petroleums. That the value of modern methods of road preservation was appreciated in this country much earlier than we have been accustomed to believe is demonstrated by the recent revival of an old patent which was granted to one John Martineau, of Elbridge, N. Y., in 1834. Petroleum had, of course, not been discovered at that time, but he claims as his invention and improvement "The application of tar, turpentine, or any of that class of tenacious, cohesive substances, reduced before use to a fluid state, and that state used as a cement, to apply to, and combine with sand, gravel, pebbles, and pulverized stone, such as is used for a Mc-Adam road, or cobble stone, the interstices of coarser material being in all cases filled,'as well as may be, with sand and gravel and cemented with tar or turpentine, to form the wearing face or surface of streets,

Jan 1, 1915

By P. E. Price, N. J. Grant

DURING the course of creep studies in iron-chromium-nickel alloys, it became necessary to establish the limits of the two-phase ferrite-austenite field at 1300°C. The shape of this region, predicted from the iron-chromium and chromium-nickel binary

Jan 1, 1960

By John M. Hird

Control of artesian ground water has played an important role in the development of Texas Gulf Sulphur's phosphate mining venture in eastern North Carolina. To facilitate dry mining methods, 60 million gpd of fresh water is pumped through wells from a limestone aquifer underlying the uniform flat-lying ore section. Hydrologic information revealed from pumping tests has been used in successfully developing a depressurizing system. Computer assistance is used to plan well patterns. High volume pumping has lowered water levels in water wells over a large area in the Coastal Plain without detrimental effects on water quality in the aquifer. Cooperative effort between mining firms will be required to control the ground water as new mines are developed in the district. An intricate observation -well system is monitored regularly over the wide area of pumping effect to ensure that gradient reversals have not caused salt water encroachment.

Jan 1, 1972

It has been established that molybdenum sesquisulphide, not molybdenite, is in equilibrium with molybdenum metal and sulphur vapor in the vicinity of 1100°C. The S2 pressure for this system has been obtained using the Knudsen orifice method and the standard free energy for the dissociation of S2. THIS work was undertaken to help in determining the thermodynamic properties of the molybdenum sulphide which is in equilibrium with metallic molybdenum and sulphur vapor in the temperature range 1025" to 1150°C. From the results of MontoroL and of Parravano and Malquori' molybdenite would be expected to be in equilibrium with molybdenum metal, while the results of Guichard indicate that a lower sulphide must be in equilibrium with the metal. Thus it was concluded that the problem warranted reconsideration, especially in view of the suspiciously low temperature independent term for the standard free-energy function for the reaction MoS² Mo + S,. The reaction was calculated and duly noted as being low by Richardson and Jeffes,' using the data of Parravano and Malquori.' Experimental Method The general method used in this investigation is that of the Knudsen orifice method for the determination of equilibrium pressure. The apparatus and technique are similar to those described for the determination of the vapor pressure of silver.% owever, a closed-end McDanel tube instead of fused silica was used to maintain the vacuum, a molybdenum effusion cell with a replaceable lid was employed instead of a silica cell, and a titanium getter maintained at run temperature was used to assure that no oxidation of the molybdenum or molybdenum sulphide was taking place. All runs were made at a residual pressure less than 10-5 mm Hg. The data are given in Table I. Runs 1 through 13 were obtained using molybdenite, analyzed 98.5 pct, from the Molybdenum Corp. of America. The remaining runs were done with a sample from the Climax Molybdenum Corp. which was their grade No. 3 and analyzed 59.87 pct Mo. The weight loss of the cell during heating up and cooling down was subtracted from the total weight loss of the cell during the run. Also, when the tem- perature was changed, the Knudsen cell was placed in the vacuum chamber and heated at temperature for several hours in order to allow the sulphide and the metal to adjust their compositions to the equilibrium values, to desorb or adsorb gases into or from the molybdenum cell itself, and to desorb any water from the molybdenum sulphide or molybdenum powder inside the cell. Water may have been adsorbed inside the cell because, after each run, the top of the cell was removed and the material in the cell was stirred to insure that a layer of molybdenum metal would not build up and obstruct the passage of sulphur vapor into the gas phase. It was established that the molybdenum cell alone decreased in weight an inappreciable amount when heated at the highest run temperature for long periods of time. There are two questions to be answered before the data in Table I can be used to calculate thermodynamic functions: 1—Which molybdenum sulphide is in equilibrium with molybdenum metal and sulphur vapor? 2—What sulphur species are present in the vapor phase? It can be assumed safely that no molybdenum is vaporized, since its vapor pressure is almost negligible at these temperatures. It will be shown subsequently that no sulphide of molybdenum is volatile. Question 1 was answered in the following way: The especially purified molybdenite, obtained from the suppliers mentioned previously, was charged

Jan 1, 1956

By D. T. Van Zandt

IN the late 1920's rotary drills began to replace the churn drills in the petroleum industry, but until the middle 1940's the churn drill was the only widely accepted means of drilling large-diameter blastholes for quarry operations. The Calcite plant of the Michigan Limestone Div., U. S. Steel Corp., was one of the first to experiment with rotary drills for quarry blasthole drilling, and the first to employ compressed air on a fully rotary rig to cool the bit and raise the cuttings to the collar of the blasthole.

Jan 8, 1954

By Herman Garlichs

The development of the extensive Southeast Missouri deposits greatly preceded that of the Iowa and Wisconsin deposits. It began about 1720 at Mine La Motte and other localities, and has continued uninterruptedly to the present time. It is estimated that this district produced about 184,000 tons of lead in the year 1916, having a value of approximately $25,000,000. This is a new high record. The Southwest Missouri orebodies were hardly known before 1845 and were not extensively developed until 1870. Lead production in Southwest Missouri for 1916 was 38,788 tons. Oklahoma produced 14,399 tons and Kansas 2,345 tons, making a total for Southwest Missouri, and the adjoining districts in Oklahoma and Kansas, of 55,532 tons of lead. The first metallurgists in Missouri were the Indian and the hunter. The early settler learned to procure his bullets either by melting ore in his camp fire or by throwing pieces of galena on an old stump and depending on the usual roasting and reaction method to obtain the metal. A little more refined method was to arrange two flat stones in the form of a, V. Wood and galena were placed in the furnace and ignited.. As heat developed, some of the metal was extracted and molded into bullets. The next step in utilizing the lead ores was the log hearth. All lead in Missouri was smelted in this crude affair before 1820. It was built on sloping ground, and consisted of a hearth of stone, surrounded on the front and two sides by a stone wall. The wall was 7 it. high in front. The top and rear end were left open and in front an arch or opening was made, forming the eye of the furnace. In front of this a pit was dug in the ground, to receive the molten metal. Large logs were rolled in at the back and made to rest upon ledges formed inside, to raise them from the hearth and to give a draft. These logs filled the entire width of the furnace. Small split logs were then set up around the two sides and the front, and the ore was piled on until the furnace was full. Finally, the mass was covered with logs and fuel until the ore was completely surrounded. A gentle heat was started, which was raised very gradually. After 12 hr. the heat was increased and continued for 12 hr. more, 24 hr. being required for each smelting. The furnace treated about 5,000 lb. per 24 hr. and the ore yielded about 50 per cent. of its metallic lead. A considerable quantity of the ore was not desulphurized, and fell between

Jan 1, 1918

By Carl F. Cline, Richard R. Vandervoort, Willis L. Barmore

THE objective of this investigation was to determine the high-temperature plastic deformation behavior of stoichiometric uranium mononitride as a function of stress and temperature. Interest in the properties of this material stems from its potential use in high-temperature nuclear reactor systems. The creep of other refractory compounds containing uranium (e.g., U02, UC) has been studied by various investigators.1"4 Fassler et al.4 have studied the creep of UN in vacuum from 1100° to 1350°C at stresses of 6000 and 8000 psi. In the present work, the creep of stoichiometric UN was investigated from 1500° to 1800°C at stresses from 2000 to 5000 psi in a partial pressure of 200 mm of nitrogen. The specimens were prepared by hot isostatic pressing of UN powder into cylinders of $ in. diam by about 1 in. high. After pressing, the specimens were heat-treated in nitrogen at 1900°C for 50 hr. The densities of individual specimens were determined by the water displacement method. All specimens were theoretically dense, based on a value of 14.32 g per cu cm.5 Principal metallic impurities in ppm by weight were: Ca, 50; Cu, 5; Fe, 30; Mg, 5; Ni, 10; and Si, 20. Oxygen content was 400 ± 50 pprn and carbon content was 100 i25 ppm. The nitrogen content was 5.56 ±0.05 wt pct. The average grain size for five specimens, as determined by the intercept method, was 0.14 i 0.01 mm. One specimen had a grain size of 2.0 mm. This large grain size is an anomaly, since all specimens had the same chemical and thermal histories. Specimens of 1/4 in. diam by 1/2 in. high were creep-tested in compression in a clam shell furnace heated by W-25 pct Re sheet elements. Temperature was measured to ilODC by an optical pyrometer which had been calibrated by a standard source. The distance between fiducial marks on the specimen was measured before placement into the furnace. The furnace chamber was evacuated to 10-5 Torr and back-filled to 200 mm N2. After heating rapidly to temperature, the load was applied and controlled to ±2 pct by an Instron testing machine. Upon initial loading, the specimen was deformed until a constant crosshead rate was obtained, then quenched to room temperature, remeasured, and replaced in the furnace. Upon subsequent reloading at temperature, the crosshead rate was constant for the selected condition indicating steady-state creep.

Jan 1, 1969

By William Victor Vietti

West Texas and New Mexico have been overshadowed by the dcvelopment in East Texas to such an extent that the area has been placed on a settled production basis by most of the operators. Considerable develop-mCnt work on both proven and unproven acreage remains to be carried 011, but the incentive, a ready and profitable market, has been lacking. The main characteristics of the fields in this area are so well known that they are not described again in this paper, which thus resolves itself into a statistical review of the more important production features of the area. Proration has been in effect during the year and has been rigorously applied with the full cooperation of all producers. Proration in West Texas and New Mexico is based in the more productive fields on a potential and acreage distribution of the allowance to the individual wells or acreage units. Potentials are determined generally by a short production test of from 1 to 4 hr.; and the hourly rate is multiplied by 24 to obtain the 24-hr. production or rated potential of the separate wells. The potential values thus set up have been questioned by many production men who are not willing to concede that the instantaneous (hourly) capacity of a well to produce is its potential capacity for a day with all other wells in the pool producing at their capacity. However, the potential of a well determined as above remains its chief rating as a measure of the permeability in place and as an indication of the possible reserve feeding that well. The acreage factor has made it unnecessary to overdevelop properties in order to obtain an allowance proportionate to neighbors who are willing to drill an excessive number of wells on a piece of acreage in the hopes of a quick drainage and a corresponding profit. Proration has resulted in an orderly development of many of the pools in this area on the base as outlined above, resulting in more reasonable spacing of wells and the more even withdrawal of oil and the ensuing expectation of high recoveries. Big Lake.—Production from the shallow or 3000-ft. pay at Big Lake totaled a little more than 3,000,000 bbl. during the year, and we may expect a smaller recovery for 1933. The deep or Ordovician production

Jan 1, 1933

By R. Bakish, C. S. Barnett

IN experiments on tantalum strained in tension, Bechtold did not observe deformation-twinning even at a temperature as low as that of liquid air.' This is an unexpected behavior for a metal of body-centered-cubic structure. Therefore, it is desirable to determine whether the lack of twinning is an inherent characteristic of this particular metal, or whether the reluctance to twin can be overcome under suitable conditions. The following experiments were performed under conditions favorable to twinning and cleavage in their competition with slip, namely, with impact loading on large-grained sheet at low temperatures. The crystallography of cleavage in tantalum sheet was also investigated carefully because of the remarkable ductility of tantalum at low temperatures and because recent tests on oxygen-embrittled tantalum had disclosed unusual cleavage behavior for a metal of this structure: cleavage primarily on (110) planes and only occasionally on {100}.2 The tantalum, supplied by Fansteel, was of 99.9 pet purity, with the chief impurities being iron (0.03 pet) and carbon (0.03 pet). Coarse grains were produced by the strain-anneal method, the anneal being 4 hr at 2000°C in a vacuum of 10-3 mm Hg, followed by furnace cooling. Impact deformation was applied in various ways: a) by hammer blows on an anvil, the specimen and anvil being immersed in liquid nitrogen ( —196°C), b) by driving a precooled center-punch into the sheet, and c) by bending around a crystallographically determined axis with a hammer blow. The impact-deformation produced bands and slip lines on the surface, Fig. 1. The bands have every appearance of being deformation twins, a) They are tilted with respect to the untwinned surface. b) They have the appearance of Neumann bands in iron, thin lens shape, some having serrated edges. c) The orientation in each is different from that of the surrounding matrix and uniform within a given band, see slip lines within them in Fig. 1. d) Upon repolishing and etching, the difference in orientation and the resemblance to Neumann bands is again evident, Fig. 2. (In this micrograph the slight bend in the bands as they cross grain boundaries was noted frequently and results from the high degree of preferred orientation in the sheet.) e) The bands persist after annealing treatments that would have removed them had they been a low-temperature martensitic phase, e.g., after an anneal of 1/2 hr at 900°C. When back-reflection Laue data were plotted for single-surface analysis of several grains, every trace of the bands in each grain could be explained by (112) planes. In addition, two of the bands were located in space by traces on two surfaces, and these also were found to lie on (112) planes within the error of the stereographic plot. Since (1 12) is the anticipated composition plane for deformation twins in body-centered-cubic metals it is felt that the observations listed above are conclusive evidence for the identification of the bands as twins. Similar tests with impact at —77° and at 25°C produced no twinning. It is concluded that the critical shear stress for slip at the rates of straining used was always low enough to prevent the applied stress from reaching the value required for twinning at these temperatures. It was noted that the serrations along the edges of the twin bands exhibited parallel crystal facets. Several similarly oriented notches are visible in Fig. 1, and a remarkable set is shown in Fig. 3. It appears from Fig. 1 and similar areas that notches are frequently associated with the intersection of a slip line with a twin, although not all such intersections are at notches. In some instances a slip line appears to enter the twin, cross it, reflect from the opposite side and recross it, producing a pattern resembling a notch but without producing the notch itself, see Fig. 1. It is suggested that the stress concentration at the end of a slip line is responsible for these details. The strain energy associated with the pile-up of dislocations at a twin boundary may be lessened by untwin-ning or failing to twin a portion of the twin band, or

Jan 1, 1959

By William F. Blake

In September I contributed an article upon Columbite in the Black Hills of Dakota to the American Journal of Science. I had not at that time seen the paper by Professor Charles A. Schaeffer, of Cornell University, upon the occurrence of tautalite in the same region," or I would have gladly made reference to it. His analysis, proving the entire thence of columbic acid, shows that the specimen he analyzed, at least, should be called tantalite, and not columbite, if the distinction between these two closely related species is to be maintained. It is hard to say where the line is to be drawn, in such cases, between two minerals, when the specific characters and the composition are so nearly the same. If the name is to be determined by the relative amounts of tantalic and columbic acids, what shall we call the mineral when these acids are present in nearly equal quantities? Preference was given in this case to the name columbite, for the reason that the specific gravity, as ascertained by the ordinary scales at command, was nearer 6 than 7. As Professor Schaeffer had only one fragment by post, while I had an abundance from many places, it may yet be found that columbic acid predominates in some of the specimens. I therefore use the name columbite or tantalite indifferently. With this explanation I proceed to give a few observations upon the occurrence of the mineral with the tin-ore of the Black Hills. There are two localities, especially, where the mineral is found in the same dike or vein as the cassiterite: 1. at the Etta mine; 2. at the Bob Ingersoll claim. At the Etta it occurs in close association with albite and feldspar in crystals from one to four or five inches broad, and from one-quarter of an inch to three inches thick. It is not in contact with or mingled with the cassiterite, and each call be

Jan 1, 1885

By T. J. Fabiniak, R. A. Dodd, R. Balow

ALTHOUGH the (111) slip direction in pure bcc metals is well established, the information on operative slip planes is less unambiguously interpreted. So far, (110) {112), and (123) slip planes have been identified, but it is not certain whether glide on (112) and (123) really occurs or if it is composite slip on non-parallel (110) planes. The second of these possibilities is supported by the work of Chen and Maddin on niobium and molybdenum, and a subsequent analysis by these same workers of slip in bcc metals generally.3 The alternative possibility is exemplified by the work of Opinsky and smoluchowsky4 who concluded that slip in Fe-Si crystals can occur on any one of the systems {110}(111), {112}(111), and {123)(111), depending on which system the resolved shear stress is highest. Allen et alS5 also found that glide in ar iron could occur on any of these three systems, the operative system being determined principally by orientation. By an analysis of crystal rotation, slip lines, and X-ray asterism Harris6 concluded that niobium also deforms on these same systems, but if one of these glide planes does not coincide with the plane of maximum resolved shear stress, composite slip on nonparallel (110) planes may occur giving a macroscopic high indices slip plane. Earlier work on iron by Vogel and Brick reached the same conclusion.7 The analysis of slip in bcc metals is made more difficult by the fact that the slip lines may be quite wavy. In fact, the generality of wavy slip lines suggests that screw dislocations slip readily from one plane to another in the (111) zone ("pencil glide") although, as noted, it is not certain whether planes other than (110) really contribute to the slip. If planes of higher indices than {110} do operate, there is a possibility they may do so more readily at higher temperature Argon and Maloof9 observed {100}{211}(111) slip in tungsten single crystals plastically strained at low temperatures, but the results were interpreted in terms of an orientation-dependence rather than temperature-dependence. Therefore, at the present time corroborative evidence for the operation of higher indices slip planes at higher temperatures is lacking. The present results were obtained during the course of an investigation into the effect of cathode and anode surface crystallography on the prebreakdown currents of vacuum insulated devices. In the experiment of particular interest, the 1/8-in.-diam anode and the in.-diam cathode were tungsten crystals (total impurities -230 ppm) with (110) and (100) faces respectively. The faces were electrolytically planed and examined for initial perfection by plastic/carbon replicas and a study of Kikuchi lines in reflection electron diffraction patterns. They were aligned precisely parallel in an insulating holder incorporated into the electron microscope, the measured microscope vacuum being 2 x 10-5 torr, and the electrode spacing 0.01524 cm. The anode structure shown in Fig. 1 was obtained

Jan 1, 1970

By Gram Curtis

The keen and close competition now ruling in the iron and steel manufacture requires imperatively, in the design and construction of the machinery employed, the fulfilment in the highest practicable degree of two cardinal conditions: economy of labor in operation, and durability. The daily pay-roll and the cost of repairs far outweigh in importance the interest on the first cost of this part of the plant. It is believed that the apparatus here described will be found to embody, in these respects, a substantial imprevement upon the present manner of handling ingots and moulds at our large steel-works. Although it includes a number of novel features, it consists essentially in the choice and grouping of certain approved economical devices specially suited to the particular service required. Fig. 1 is a plan, and Figs. 2 and 3 are elevations of parts of a Bessemer converting-house, together with a small portion of the blooming-mill—suficient to illustrate clearly the means and manner of handling the ingots and moulds. A short cable-road of simple form, somewhat similar to those used

Jan 1, 1892

By P. T. Gallagher, W. A. Oates, J. A. Lambert

FAIRLY extensive equilibrium data exists for carbon dissolved in r iron.1-8 However the temperature coefficients of the carbon activity, ac , are insufficierltly preciseto reveal whether the heat of solution of carbon, ?HC , varies with composition. It is doubtful

Jan 1, 1970

By Y. Mishima, R. Shiromizu

THE equilibrium y phase in Cu-Be alloys forms by discontinuous precipitation, the new phase nucleating at the grain boundaries and growing into grains on both sides of the boundary. When the alloy is aged above 500°C, however, growth may take place into only one of the grains.1'2 In A1-Ag alloys it is known that the precipitate has the same orientation as the grain in which no growth takes place.3, 4 This was confirmed in the present investigation on a Cu-Be alloy. A Cu-1.79 wt pct Be alloy was solution-treated at 810°C for 2+ hr, quenched into water at O°C, and aged at 600°C for 1 hr in a salt bath. The specimen was thinned by chemical polishing and electropolishing at room temperature in a solution of H3PO4 saturated with CrOs. The foil produced was examined in a JEM 150 electron microscope operating at 150 kv. Fig. 1 shows precipitates growing on only one side of the grain boundary. The black platelike precipitates were identified as the y phase. Electron dif-

Jan 1, 1969

By Ralph Sherman

IN these days of intense competition for the domestic fuel market much is heard of the low efficiencies with which solid fuels, and most particularly bituminous coal, are burned in domestic heating equipment. In contrast to the every-day operating efficiencies of 85 and 90 per cent in large, central, electric-generating stations, efficiencies of 50 per cent and lower are cited for the hand-fired home furnace. Just as the miles per gallon of gasoline is only one of the factors that determine the cost of operation of an automobile, so the thermal efficiency is only one factor in the cost of domestic or other heating. The purpose of this paper is to analyze the total costs of domestic heating by various fuels and types of equipment, to determine the relative importance of efficiency and other factors, and to discuss what this signifies relative to the future of the use of fuels in the home.

Jan 1, 1933

By Che, C. W. Spencer, C. A. Steidel, Yu Li

Grain boundary grooving as it occurs in a 5.5-deg simple-tilt nickel bicrystal immersed in a saturated Ni-S liquid has been studied. A 1/3 (t= time) dependence for the depth of the groove indicates that the rate -controlling meckanism for groove developvnent is volume diffusion in the liquid. The activation energy for the diffusive process is estimated at 15 kcal per mole. Using an extended form of W. W. Mullins&apos; analysis for grooving reactions, a computer is employed to fit the appropriate diffusion equation by a numerical method. From the analysis a possible method of measuring L.S. the solid-liquid interfacial tension is demonstrated. WHEN a polycrystalline solid is heated in equilibrium with a saturated fluid phase, grooves will form at the intersections of the grain boundaries and surface. The equilibrium root angle of these grooves is determined by the balance between the grain boundary and solid-fluid interfacial tensions. The grooves deepen and widen with time due to a difference in chemical potential between the flat interface and the curved interface of the groove. In this investigation solid-liquid interaction at a grain boundary is studied, with the object to determine the mechanism of grain boundary grooving in the presence of a saturated liquid. Extension of Mullin analysis then permits the estimation of the solid-liquid interfacial tension. Herring has demonstrated by dimensional analysis that the quasi-steady state change of the dimensions of a small particle during sintering is proportional flow, evaporation-condensation, volume-diffusion, and surface-diffusion mechanisms, respectively, if geometric similarity of consecutive configurations of the particles holds. Mullins has extended this analysis to grain boundary grooving. In the case of shallow grooves he solves the diffusion equations for evaporation-condensation, volume-diffusion, and surface-diffusion mechanisms, and obtains the same time dependence for any linear dimension of a groove as Herring found for the change in dimension of small particles. In Mullins&apos; analysis2&apos;3 grain boundary grooving of a bicrystal by volume diffusion in the presence of a saturated fluid phase was considered. Several assumptions were made prior to the analysis: 1) the solid-fluid interfacial tension is independent of crystallographic orientation; 2) the Gibbs-Thompson equation relating curvature and chemical potential is applicable at the solid-fluid interface; 3) the relaxation time of the diffusion field is small compared with the time for appreciable changes in the curvature of the groove, so that the diffusion is divergence-less; and 4) the groove has a small slope relative to the initial flat interface. Usually this last condition is fulfilled only for solid-gas systems. The solution of the diffusion equation under the above conditions produces a t1/3 dependence for any linear dimension of the groove in the case where volume diffusion is rate-controlling. The t1/3 dependence is valid because geometric similarity of the grooves exists for all time. EXPERIMENT In the experiment a 5.5-deg nickel bicrystal of <100> simple-tilt orientation was used.4 Grooving was studied in the presence of a saturated Ni-S liquid alloy as a function of time at 750°, 800°, 850°, and 900°C. A low-angle bicrystal was chosen for study to insure that 2L.S. > .b., where l.s.

Jan 1, 1964

By A. Eilers

(Butte Meeting, August, 1913.) A NUMBER of the copper refineries in this country have lately separated some of the rarer metals from the slimes in the refinery tanks One of these has furnished me the following table of recoveries from given amounts of blister. I publish . this to show the proportions, to gold and silver and to each other, in which these rarer metals may be expected to occur in copper from certain localities.

Jan 6, 1913

By Howard C. Dunkle

Various factors can affect the quality of B1112 and B1113 steel as produced in a bessemer plant; among them: vessel-charging practice, blowing practice, ingot-pouring practice, ingot delivery-time practice, pit-heating practices, and ingot-rolling practice. Evaluation of the influence of ingot delivery time on quality has been chosen as the subject for this paper because this time is completely within the control of the operator, and on this particular factor there is a tremendous amount of information in the dusty archives of the average steel plant. In order to know how much improvement can be made and when attention should be directed to other factors that influence quality, in the continual struggle for improvement, the effect of ingot delivery time must be accurately evaluated. Once this is done, the importance of other variables can be accurately obtained, thus eliminating the necessity of resorting to opinions that are of doubtful value at best. In the study described herein, extensive use was made of the statistical card system as a method of determining the effect of ingot delivery time as a quality factor in bessemer screw-stock grades by simple direct correlation. The value of this statistical method as a means of accurately determining the influence of various factors has been amply demonstrated by Work1 for the bessemer process and by Hand and Gould2 and Fetters and Chipman3 for the open-hearth process. The quality records of 300,000 tons of bessemer screw-stock billets were used in this study of the effect of ingot delivery time on the rejections for breaks, pipe, check and seams. The reduction in the number of rejections for poor quality reduces the costs and increases the productivity per man-hour. The operator today, more than ever before, must know how to keep costs down, how to do it most quickly and in the best way, and how to obtain the highest quality in line with the ever increasing demands of the customer. It is necessary for him to know the individual relations and interrelations between various factors affecting the quality of the manufactured product if he is to produce material that will meet competitively the cost, performance, and quality demands of the trade. SIGNIFICANCE OF STEEL MANGANESE, MIXER SILICON AND STEEL SULPHUR AS QUALITY FACTORS In order to obtain the highest grade of material it is necessary to control many factors-not just one or two, as operators

Jan 1, 1945

By Elmars Ence, Harold Margolin

BUMPS, Kessler, and Hansenl have reported that the solubility of aluminum in or titanium is about 31 pct at 1240°C. Despite this large solubility, and no evidence of other phenomena, alloys containing 12 pct A1 or more were found to be brittle. The

Jan 1, 1958

By Paul W. Jeran, Vladimir Adamek

Characteristics of surface deformations i.e., sub¬sidence, inclination, curvature and horizontal strains, are evaluated, based on information obtained by direct field measurements over three longwall panels in the Northern Appalachian Coalfield. Surface deformations have been precomputed using Bals&apos; and Knothe&apos;s theories. The results have been compared with Bureau of Mines field data to evaluate the applicability of the two theories to the U.S. min¬ing conditions. Measured horizontal movements and the resulting horizontal strains differ as much as 300 percent from precomputed values. Topography has no detectable effect on vertical movements but appears to have substantial effect on the development of horizontal strains. The horizontal deformations computed from our field measurements generally exceed the limits used in other countries to protect surface structures.

Jan 1, 1982