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By D. Beregekoff, W. D. Forgeng

In the routine examinatlion of a wide variety of metal specimens it is sometimes necessary to have special methods of polishing in order to retain and reveal certain details in each specimen. Among such special cases is the retention of graphite in malleable and gray cast irons, the preservation of all types of non metallic inclusions in both hard and soft steels, obtaining a scratch-frec surface with soft metals, and avoiding the usual relief effects with very hard specimen. such as tool metals c3o1ltaining various carbide and nitride phases. It, is the purpose of this paper to give an account of some of these special polishing methods in use at the Union Carbide and Carbon Research Laboratories. The polishing procedures outlined have been found to give uniform results. It is obvious that only general rules and the most important working details can be given here. Following these rules, the polisher can obtain satisfactory results if he possesses the necessary patience and has a sincere desire to give as nearly perfect a finish as possible to his work. Procedure The specimen is flattened with considerablecare on a file or sharp cutting sanding belt, since the initial production of a flat surfacc greatly facilitatcs subscqucnt polishing. The polishing motors have two speed., 600 and 1200 r.p.111. ,It higher speeds specimens arc likely to he over-Ileated, therefore the high speed is used only when a saving of time is important. The following abrasive papers are used consecutively: Yo. 2, So. 1, No. 0, No. 00 and No. 000. The final wet polishing is done oil a cloth-covercd metal disk. Woolen broadcloth of the best quality and capable of resisting severe pressure is most commonly used on the last lap. . polishing felt of the type used for polishing optical glass has been found equally satisfactory and is much stronger than broadcloth. For retaining inclusions and graphite, a hard cloth with very little residence, such as

Jan 1, 1939

By T. Sterry Hunt

I HAVE already referred to this interesting locality in the opening address, but at the request of some of the members of the Institute, brought before them specimens of the ore and the accompanying rock. The ore, which is cassiterite, is also met with elsewhere in Maine, at Paris and Hebron, but it there occurs associated with orthoclase, quartz, tourmaline, and beryl, in concretionary granite veins, which cut the micaceous gneisses of the White Mountain series. At Winslow the veins traverse an impure gray micaceous limestone, which is found in many parts of this region, and is subordinate to the same gneissic series. The veins, which are seldom more than an inch or two in thickness, are abundant through a considerable breadth of the rock, and are interlaminated with it, occupying places between the sedimentary layers, which are distinctly marked by different shades of color. Occasionally, however, they cut across the stratification for a little distance, showing that the disrupting action was not always confined to tearing the layers apart. The vein-stone consists of purple fluor-spar, and silvery white mica with quartz. In this gangue the cassiterite, nearly black in color, is disseminated in small crystalline masses, sometimes one-half an inch in diameter, and is associated with a little mispickel. I have only seen the veins as exposed at a single point, but was informed that similar veins holding the ore are met with at a distance of several thousand feet

By AIME AIME

FOUR separate groups of conveyors are installed in the Morenci Reduction Works as follows: (1) Ore-handling conveyors from the primary crushing plant to the coarse ore bin, from the coarse-ore bin to the secondary crushing plant, and from the secondary crushing plant to the ore bin in the concentrator plant. (2) Conveyors in the mill section of the concentrator plant. (3) Conveyors handling concentrate from the filter plant to the bedding plant, and from this plant to the smelter. (4) Conveyors handling flux and custom ore in the smelter crushing plant and to the bin at the bedding plant.

Jan 1, 1942

By Charles M. Behre

Under the caption "fault," geologists intend to include all mass movements of solid rocks over adjacent rock masses. When these are studied long after their origin, however, circumstances make it possible to recognize as "fault" only formations showing clear evidence of actual movement of one side with respect to the other. Necessarily the chief evidence consists of the offset of a vein, bed, or other key structure. Planes of movement parallel to the bedding, or nearly so, are recognized with difficulty or are overlooked and hence many important faults are wholly unrecorded. Indeed, among standard American references on structural geology, one alone emphasizes the importance of bedding-plane movements and that one only briefly1. For some time the writer, cognizant of this difficulty, has paid special attention to such movements, both as observed in the field and as recorded in the literature. It is believed that enough data are now at hand to justify a short discussion. Its purposes are fivefold. It is desired first to briefly classify and describe at least the more common kinds of bedding-plane faults, and second, to examine the causes and manner of their formation, at least in instances where the subject has not yet been well covered by other investigators. Third, certain by-products of bedding-plane movements are of such conspicuous importance to the economic geologist and mining engineer as to merit mention. Fourth, concrete illustrations should be placed before the reader in order to lend reality and to furnish a basis of comparison with his experience; such illustrations will necessarily be scattered through the text of this paper. They are only in part from the writer's own field observations. The fifth and prime objective of this paper is to direct attention to the great importance of movements on the bedding planes, in the hope that the recognition of such movements and their significance may simplify mining problems.

Jan 1, 1937

By P. Somasundaran

Almost a decade has elapsed since the problem of fine particles processing was first discussed at the National Science Foundation workshop in Arden House (Somasundaran and Fuerstenau, 1976). Problems involved in processing fines are as enormous now as they were then. We still lose 20 to 50% of mineral values during the processing of many ores. While the problem's magnitude has remained at as high a level as ever, our perspective on the causes for the difficulties, I believe, has changed. While we do not yet see any grand unified solution to all the problems in this area, I do feel that we are beginning to get an understanding of the basic reasons for the behavior of fines. I would like to share my views on the fundamental reasons for the problems we face. They are based essentially on results obtained during the last few years. A decade ago, I presented the reasons shown in the [Fig. 1] as the causes for the difficulties in separating fines. We have seen the same type of information discussed by others during the years since then. I now believe that these are not the only primary causes. Indeed, they do contribute, but there are other major reasons we ought to recognize. Mass certainly would have its effect, but since microorganisms and even ions can be separated from each other using flotation, provided correct conditions are used. I do not believe that fines 10,000 times bigger suffer fundamentally from their smallness or lightness. Similarly, the surface energy increase cannot be as important a fundamental factor since, theoretically, we should not see significant changes in surface energy until we get down to particles a hundred times finer than we are concerned with. Increase in surface areas, again, cannot be a primary problem except for an increase in reagent consumption. What possibly could be the reasons? I have added these three items to the list in [Fig. 1]: morphology, mineralogy, and surface chemical composition. Differences that I believe are partly responsible for the behavior of mineral fines are those due to alterations in morphology or mineralogy and surface chemical composition with decrease in size.

Jan 1, 1985

By E. L. Claridge, K. S. Lee

Areal sweep efficiency of oil displacement by enhanced-viscosity water exhibiting pseudoplastic behavior was measured in a Hele-Shaw model representing one-quarter of a five-spot pattern. The pseudoplasticity of polymer solutions and the velocity distribution in the five-spot pattern produced a condition under which the mobility ratio between the displacing and the displaced fluid could not be assigned a single value. Instead, the movement of the displacement front is governed by local mobility ratios which are also time dependent. The areal sweep at breakthrough with polymer solutions was poorer than the sweep obtained with Newtonian fluids of comparable viscosity. However, the areal sweep at 1 PV throughput was greatly improved as compared to flood water without polymer. It was also demonstrated that, even after the oil-cut had declined to a low value during a regular waterflood, switching to polymer flood efficiently swept out the oil remaining in the model. INTRODUCTION The behavior of fluid displacements in isotropic porous media for various patterns of injection and production wells has been extensively investigated.1-7 These investigations all concerned Newtonian fluids, i.e., the viscosity of each fluid was constant regardless of flow rate. The generally unfavorable influence on areal sweep efficiency of higher mobility of the displacing fluid as compared to the mobility of the displaced fluid has been established for both miscible and immiscible fluids. The principle was also established that a close correspondence exists between miscible and immiscible flood front behavior,2, 3 although oil recovery in a waterflood at unfavorable mobility ratio may be less than that observed in a miscible displacement at the same mobility ratio. This is true even when oil recovery is expressed on the basis of movable oil. The reason is that oil saturation only slowly achieves its final value behind the water-flood front in accordance with the Buckley-Leverett8 simultaneous flow relations. It is convenient to use miscible displacements for laboratory simulation of waterflood frontal advance since the interfacial tension forces which are negligible in proportion to viscous forces on a reservoir scale9 are thus made nonoperative in the laboratory model. For miscible displacements, the Hele-Shaw type of model adequately represents a porous medium so long as the appropriate scaling rules5-10 are observed in its design and operation. During simulation of waterflood front behavior in the laboratory by using miscible displacements, the behavior of connate water may ordinarily be disregarded since it is usually indistinguishable from flood water in this process. However, when the flood water is deliberately thickened to improve the mobility ratio between water and oil. the effect on the sweep efficiency due to generation of a connate water bank during the process must be considered. In a uniform porous medium, such a bank is generated11 and efficiently displaced by injection of thickened water.l2 The oil originally in-place at the start of the waterflood is then displaced by connate water followed by thickened water. If the flood water must be thickened to obtain a favorable mobility ratio, the mobility of the oil phase is appreciably less than that of the connate water. Hence, the oil phase is inefficiently displaced by the connate water bank, and a considerable proportion of the oil comes in contact with and is displaced by the thickened waterflood front' A recent study 12 of five-spot displacements using miscible Newtonian fluids in which connate water banks of various sizes were simulated shows that, for connate water banks as large as 40 percent of 1 PV, major improvements in sweep efficiency resulted from use of a thickened

Jan 1, 1969

By W. A. Foster

NINETY years after the Riddle nickel deposit N was discovered in Oregon in 1864, Hanna Coal & Ore Corp. began mining operations. Until 1954 much prospecting and preliminary development work had been done on the property, but no ore had been shipped other than for metallurgical testing. The deposit is being explored by churn drilling and trenching, and a few test shafts have been put down for the purpose of studying the ore in place, determining volume and moisture factors, and gathering bulk samples for pilot plant and smelter tests. In churn drilling, 6-in. casing is driven down 2 or 3 ft behind the drill bit and bottomed at each 5-ft interval. All the sludge for each cased 5-ft interval is dumped through a splitter and one eighth is saved and analyzed. Drillholes are stopped after going through the ore zone and penetrating fresh peridotite in which the nickel content is less than 0.5 pct.

Jan 8, 1957

By H. A. Guess

For a number of years I have used for the commercial wet assay of lead generally the ammonium molydate, and occa-sionally the ferrocyanide method. These well-known methods need no detailed description here. In the ore-selling and ore-buying establiahments of the West, 90 per cent. of all wet lead-assays are made by one or the other, and at least nine-tenths of this proportion by the molybdate method. A procedure so well-established must have merit; and, in

Jan 1, 1905

By Mark R. Lamb

The treatment of slime is of special interest to those engaged in cyaniding gold- and silver-ores. The usual practice is to make as small a percentage of slime as possible. In many instances the slime is given no treatment, but is impounded in dams in the hope that the future will develop some method of economically treating this product. The filter-press was the first step upward from ordinary decantation, but, on account of heavy labor-charge and high cost, its use has been limited to high-grade material. The slime at the Combination mill at Goldfield averages perhaps $20 per ton, and although the values are quickly dis solved the filter-press installation was not entirely satisfactory, resulting in the erection of the canvas-cell filter, developed by Chas. Butters and his staff. This filter is a great improvement over the filter-press, and the following description of it will be of interest to those engaged in treating slime produced in crushing ores, especially in view of the fact that, by the use of this filter, slime can be treated at a lesser cost and with a higher percentage of gold- or silver-extraction than in the ordinary treatment of sand; and, moreover, the initial outlay for an all-sliming plant is less than that for the ordinary sand- and slime-plant. The economy of construction of the Butters filter-plant is clearly shown in Figs. 1 and 2, which illustrate the 20-frame filter of 40 tons capacity, now being installed by the Nevada Goldfield Reduction Co. In this construction the slime-pump is so connected that it call pump to or from either tank or the filter by changing the valve-settinga—a combination which is necessary in this particular installation, since sufficient fall is not available for filling and discharging the filter by gravity. Ordinarily, a slime-plant comprises: a filter-box with frames

Jan 1, 1908

By N. Tiner

In an article on magnesium and its alloys, Gann and Winston! stated that manganese has a limited solubility in the liquid state. W. Schmidt2 showed a diagram according to Joseph Ruhrmann indicating that the solubility of manganese in liquid magnesium falls from about 2.65 per cent at 790°C. to about 0.5 per cent at 675°C. The curve was extrapolated to show zero solubility at the melting point of pure magnesium (Fig. I). This work suggested that at the lowest manganese contents it was not possible to detect either a eutectic or the formation of a solid solution, so that manganese was stated to be present in the structure as large individual crystals. Two years after the presentation of, these results, Gann3 brought evidence to show that some manganese is capable of dissolving to form a solid solution, any excess of manganese present then assuming chiefly the form of small blue-gray particles scattered throughout the primary magnesium crystals, occasionally in clusters but seldom at the boundaries. He presented micrographs of cast alloys containing 0.1, 0.4 and 1.0 per cent manganese that show a small amount of coring around the individual particles due to solid solution, and indicate that the location of the manganese particles is closely associated with the original dendritic structure of the primary crystallization. He also pointed out that the amount of manganese that can be dissolved in magnesium depends on the amount of other alloying elements present, the effect of the second alloying element being to decrease the amount of manganese retained in the alloy. E. Schmid and G. Siebe14 have determined the solid solubility of manganese and its variation with temperature by means of precision X-ray diffraction measurements. They found that the solubility is 3.4 per cent at 645°C. and decreases to practically zero at 200°C. It is apparent that the X-ray diffraction measurements of Schmid and Siebel are not in agreement with the results of Ruhrmann as presented by Schmidt. This disagreement, and also the lack of data on magnesium-aluminum-manganese and magnesium-zinc-manganese systems, led the author to the present investigation, to determine accurately the liquid solubility of manganese and its variation with temperature. Experimental Method The experimental method for making solubility determinations consists of saturating the molten magnesium or the alloys with manganese at various temperatures and analyzing the dip samples taken from these melts. Melting is carried out in a cylindrical steel pot heated by an electric resistance furnace. The pot had a metallic outside coating to protect the steel against oxidation, and a graphite inside lining to prevent the contamination of the melt by prolonged contact with iron. The inside diameter of the pot was 4 in. and the depth 12 inches.

Jan 1, 1945

By D. V. BURR

THE ORIGINAL HUDSON RIVER TUNNEL. NOT quite forty years ago a man of uncommon character entered New York. He had several hundred thousand dollars earned by railroad building in the Nest. He was not an engineer, but he had ideas of engineering work which he was destined to prove correct.. He introduced new ways of tunneling, but his plans had only one distinguishing feature-they were simply interesting as showing how such work could be done; they added nothing to the science, have never been used since his clay, and never will be used again. Engineers of repute ridiculed his proposition ; he was an Ishmael in the profession. But if engineers looked askance at him, he certainly returned their contempt in the heartiest fashion, and had no hesitancy about expressing his views of them individually and collectively. This worked to. his disadvantage when he afterward tried to raise the means to go on with the work. He found that the opinion of engineers was respected by financiers, and that money would not flow contrary to their advice. While his conception of large constructions was distinguishingly original, much more marked was his method of demonstrating the feasibility of, his schemes. In the present clays of great undertakings it is the custom to make the other man pay for the experiments. But the man from the West had other notions of how the thing ought to be done. Having wonderful confidence in his own ability and in his perception of the task before him, he used up all his own money before seeking outside assistance. By building several hundred,, feet of tunnel he proved the correctness of his theory, and the tunnel then dug forms a part of the present tube. The result-he failed to finish the tunnel. He was blind in

Mar 1, 1908

By O. N. Carlson, S. A. Bradford

Discontinuous yielding in tensile tests was observed in V-O alloys in the temperature ranges of 150° to 175°C and also 350° to 400°C. The magnitude and intensity of the serrations were found to vary considerably with oxygen content. Maxima were observed in tensile and yield strengths and in the strain-hardening coefficient at the higher temperature only. The strain rate sensitivity was observed to be negative between 150° and 400°C. THIS investigation was undertaken to study the effect of oxygen on the tensile properties of iodide vanadium in the temperature range of 25o to 450°C. Brown1 observed an increase in strength between room temperature and 400°C in vanadium metal, and found that oxygen and nitrogen had a rather pronounced effect on the strength and ductility. A maximum in the tensile strength was observed by Rostoker et al.2 near 300oC and by Pugh3 around 450°C for calcium-reduced vanadium. Pugh also found a maximum in the yield strength and in the strain-hardening exponent, and minima in the elongation and strain rate sensitivity at the same temperature. Eustice and Carlson4 reported the appearance of serrations in the stress-strain curves between 140° and 180°C in iodide vanadium containing 600 ppm O. These anomalies in the mechanical properties indicate that strain aging occurs in vanadium, but the impurity or impurities responsible for the above-mentioned effects have not been identified. The phenomenon of strain aging is usually characterized by the return of the yield point after interruption of a strength test. In the temperature range where strain aging occurs, the yield and tensile strengths attain maximum values, elongation and strain rate sensitivity exhibit minima, and discontinuous yielding is generally observed in the stress-strain curve. Cottrell5, 6 has postulated that strain aging is due to the migration of solute atoms to dislocation sites to produce locking after the dislocations have broken free from their impurity atmospheres during the initial yielding. At the strain-aging temperature the process is a dynamic one in which the solute impurity atoms diffuse to the vicinity of the moving disloca- tion producing "locking" which gives rise to maxima in the tensile strength and serrations in the elongation curves. Cottrel17 has noted that discontinuous yielding in iron occurs when the diffusion coefficient of nitrogen, D, and the strain rate, i, are related by D = 10-9 €. EXPERTMENTAL PROCEDURE The vanadium metal employed in this study was prepared by the iodide refining process as described by Carlson and owen.8 A representative analysis of the vanadium used in this investigation was: 150 ppm O, <5 ppm N, <1 ppm H, 150 ppm C, 150 ppm Fe, 70 ppm Cr, <50 ppm Si, 30ppm Cu, 20 ppm Ni, <20 ppm Ca, <20 ppm Mg and <20 ppm Ti. Alloys containing from 200 to 1800 ppm O, all of which lie in the solid solution range of the V-O system, were prepared by arc melting vanadium together with portions of a high-oxygen master alloy. The master alloy was prepared by tamping pure V2O5 into holes drilled in a vanadium ingot and arc melting this five or six times in an inert gas atmosphere, inverting the button between each melting step. The oxygen content of the master alloy was then determined by vacuum fusion analysis. Vanadium containing less than 150 ppm O was prepared in the following manner. A bar of iodide vanadium was deoxidized by sealing it in a tantalum crucible with a few grams of high-purity calcium. This was held at 1100°C for 4 days to allow time for the oxygen to diffuse to the surface and to react with the calcium vapors. The calcium oxide product was later dissolved from the surface of the bar with dilute acetic acid. In this way vanadium containing from 20 to 50 ppm O was prepared. Sample Preparation. The are-melted ingots were cold swaged into 3/16-in. diam rods and these were machined into cylindrical tensile specimens with a reduced section of 1.00-in. length and 0.120-in. diam. The test specimens were annealed for 4 hr at 900°C in a dynamic vacuum of mm of Hg to remove hydrogen from the metal. This recrystal-lization treatment produced a uniformly fine-grained structure with a mean grain size of approximately 0.06-mm diam. The oxygen contents reported in this paper were determined by a vacuum fusion analysis of the tensile specimens after testing. Analyses for other interstitial or metallic impurities showed no significant changes from that of the original material. Tension Tests. Tension tests were performed on a screw-driven tensile machine at a constant cross-head speed of 0.01 in. per min. Tests at elevated temperatures were carried out by heating the

Jan 1, 1962

By A. M. Gaudin, F. W. Bowdish

MINERAL dressing is an industrial art concerned with the treatment and separation of solids suspended in fluids. Knowledge and evaluation of the area of solid-fluid interface is important in all cases except those involving only large pieces of solid. In fact, many problems relating to comminution, to flotation, to thickening and classification, could be dealt with more rationally if the interfacial area were known. A number of methods have been proposed for the measurement of the surface of certain finely divided solids. Among them are methods using rate of dissolution of the solid,7 its magnetic remanence,3 the turbidity of its suspension,8 and the character of the size distribution of the material.9 The first two are limited to one mineralogical species per sample; the third has certain optical limitations, especially for mineral mixtures, and the fourth is based on an extrapolation of uncertain validity. The need of a better and more general method of surface determination has long been felt, therefore. The method of P. H. Emmett,4 based upon the low-temperature adsorption of vapors, appears to fulfill this need. This method consists in determining the amount of nitrogen that is adsorbed by a given sample of solid at the temperature of boiling nitrogen. The more surface there is on the solid-both internal and external-the more nitrogen is abstracted. In actual operation, the method is somewhat less simple than has been stated so far, in that the nitrogen is adsorbed in an incomplete layer, the completeness and thickness of the layer being related to the pressure of the nitrogen in contact with the sample .2 This circumstance makes it necessary to determine the nitrogen adsorption for three or more values of the nitrogen pressure. APPARATUS In the Richards Mineral Dressing Laboratories an Emmett apparatus has been built and tested (Figs. 1 and 2). A mechanical vacuum pump B and a mercury diffusion pump A work in series to give a high vacuum. The sample, placed in bulb D, can be evacuated by this pump train by suitable operation of the stopcocks in the glass tubing that connects the various parts of the apparatus. C is a McLeod gauge, used to ascertain the order of magnitude of the vacuum obtained, and not for accurate pressure measurements. Pressure measurements are made in the mercury manometer F and gas-volume measurements in the gas burette E. Gases are stored in flasks L (nitrogen) and K (helium), arranged so that definite quantities of these gases can be introduced into

Jan 1, 1944

By Heber Cole

THE gypsum industry of Canada, like all others connected with the construction business, has felt the full effect of the depression during the past few years, and sales of its products have been greatly curtailed. The year 1934, however, saw a decided turn for the better and a gradual but steady improvement is noticeable in all its branches. In many ways the depression has been a blessing in disguise to the gypsum industry; during the years from 1926 to 1930, demand increased so rapidly that companies were forced to expand and often new apparatus and machinery were placed in operation regardless of expense, or plants already existing were taxed to their limit and forced to keep running with the minimum amount of repairs. The depression, therefore, has really given the industry what might be called a breathing spell, in which it has had time to take stock of its position, to reduce its costs of production, to devote more serious attention to the quality of its products, and to con-solidate its operations into a smooth working whole, which as conditions improve will enable it to meet the demands of the trade with more varied products of a quality hitherto unattained. Progress in the gypsum industry, however, has not been confined to the years of the depression, for some of the greatest advances occurred under the spur of increased demand for its products by the building trade. The purpose of this paper is to review briefly some of the out-standing trends in the development of the gypsum industry in Canada during the past 10 or 12 years.

Jan 1, 1935

By J. R. Low, M. Gensamer

During the course of an investigation into the drawability of automobile-body sheet steel, it became apparent that certain advantages would be possessed by a deep-drawing steel with a very low yield strength, but almost normal tensile strength, provided a reduction in yield strength could be accomplished without sacrifice of ductility and fine grain size. It would also be desirable to have this steel free from strain-aging; that is, free from the tendency for the yield point to return after it had been eliminated by straining. It was known that, wet hydrogen treatment acted to eliminate aging, but as carried out by other investigators, at relatively high temperatures, this treatment resulted in grain coarsening. It has been established by some of the experiments reported in this paper that all of these objectives can be accomplished by treatment in wet hydrogen at a low temperature, in the neighborhood of 72o°C. The time of treatment is relatively short (about 3 hr, to completion with 20-gauge sheet) if the water content of the hydrogen atmosphere is made fairly high, say aimost 30 per cent by volume. At this temperature. the grain size remains fine in the time required. After this treatment sheet reduced the usual amount by cold-rolling has a grain size of about A.S.T.M. No. 7. The yield point is completely eliminated, and the yield strength is reduced to a very low value, in the neighborhood of 15,000 lb. per sq. in. The stress-strain curve departs gradually from the straight-line elastic part after the fashion of nonferrous deep-drawing alloys. This elimination of the yield point is accompanied by a verv low indentation hardness; for example, 32 Rockwell B or even lower. There is no aging as measured by increase in the yield strength upon aging at room temperature or for 3 hr. at 200°C., after stretching about 10 per cent in tension. Tensile strength is only slightly less than the box-annealed sheet, seldom dropping much below 40,-ooo lb. per sq. in. Elongation is practically unchanged, or increased slightly. The term yield point, as here used, refers to the phenomenon of heterogeneous deformation occurring at a substantiallv constant load, observed principally in annealed low-carbon steels. If such a steel is loaded in tension, the load increases steadily with elastic strain, suddenly falls, fluctuates slightly about some constant value for a time and then begins to rise again as deformation proceeds. The maximum initial load before the sudden drop is generally called the "upper yield point"; the value of the load where deformation proceeds at a

Jan 1, 1944

By J. R. Low, M. Gensamer

During the course of an investigation into the drawability of automobile-body sheet steel, it became apparent that certain advantages would be possessed by a deep-drawing steel with a very low yield strength, but almost normal tensile strength, provided a reduction in yield strength could be accomplished without sacrifice of ductility and fine grain size. It would also be desirable to have this steel free from strain-aging; that is, free from the tendency for the yield point to return after it had been eliminated by straining. It was known that, wet hydrogen treatment acted to eliminate aging, but as carried out by other investigators, at relatively high temperatures, this treatment resulted in grain coarsening. It has been established by some of the experiments reported in this paper that all of these objectives can be accomplished by treatment in wet hydrogen at a low temperature, in the neighborhood of 72o°C. The time of treatment is relatively short (about 3 hr, to completion with 20-gauge sheet) if the water content of the hydrogen atmosphere is made fairly high, say aimost 30 per cent by volume. At this temperature. the grain size remains fine in the time required. After this treatment sheet reduced the usual amount by cold-rolling has a grain size of about A.S.T.M. No. 7. The yield point is completely eliminated, and the yield strength is reduced to a very low value, in the neighborhood of 15,000 lb. per sq. in. The stress-strain curve departs gradually from the straight-line elastic part after the fashion of nonferrous deep-drawing alloys. This elimination of the yield point is accompanied by a verv low indentation hardness; for example, 32 Rockwell B or even lower. There is no aging as measured by increase in the yield strength upon aging at room temperature or for 3 hr. at 200°C., after stretching about 10 per cent in tension. Tensile strength is only slightly less than the box-annealed sheet, seldom dropping much below 40,-ooo lb. per sq. in. Elongation is practically unchanged, or increased slightly. The term yield point, as here used, refers to the phenomenon of heterogeneous deformation occurring at a substantiallv constant load, observed principally in annealed low-carbon steels. If such a steel is loaded in tension, the load increases steadily with elastic strain, suddenly falls, fluctuates slightly about some constant value for a time and then begins to rise again as deformation proceeds. The maximum initial load before the sudden drop is generally called the "upper yield point"; the value of the load where deformation proceeds at a

Jan 1, 1944

By J. R. Low, M. Gensamer

During the course of an investigation into the drawability of automobile-body sheet steel, it became apparent that certain advantages would be possessed by a deep-drawing steel with a very low yield strength, but almost normal tensile strength, provided a reduction in yield strength could be accomplished without sacrifice of ductility and fine grain size. It would also be desirable to have this steel free from strainaging; that is, free from the tendency for the yield point to return after it had been eliminated by straining. It was known that wet hydrogen treatment acted to eliminate aging, but as carried out by other investigators, at relatively high temperatures, this treatment resulted in grain coarsening. It has been established by some of the experiments reported in this paper that all of these objectives can be accomplished by treatment in wet hydrogen at a low temperature, in the neighborhood of 720°C. The time of treatment is relatively short (about 3 hr. to completion with 20-gauge sheet) if the water content of the hydrogen atmosphere is made fairly high, say almost 30 per cent by volume. At this temperature, the grain size remains fine in the time required. After this treatment sheet reduced the usual amount by cold-rolling has a grain size of about A.S.T.M. No. 7. The yield point is completely eliminated, and the yield strength is reduced to a very low value, in the neighborhood of 15,000 lb. per sq. in. The stress-strain curve departs gradually from the straight-line elastic part after the fashion of nonferrous deep-drawing alloys. This elimination of the yield point is accompanied by a very low indentation hardness; for example, 32 Rockwell B or even lower. There is no aging as measured by increase in the yield strength upon aging at room temperature or for 3 hr. at 200°C., after stretching about 10 per cent in tension. Tensile strength is only slightly less than the box-annealed sheet, seldom dropping much below 40,000 lb. per sq. in. Elongation is practically unchanged, or increased slightly. The term yield point, as here used, refers to the phenomenon of heterogeneous deformation occurring at a substantially constant load, observed principally in annealed low-carbon steels. If such a steel is loaded in tension, the load increases steadily with elastic strain, suddenly falls, fluctuates slightly about some constant value for a time and then begins to rise again as deformation proceeds. The maximum initial load before the sudden drop is generally called the "upper yield point"; the value of the load where deformation proceeds at a

Jan 1, 1943

By T. H. Aldrich

The Aldrich Mining Go. holds under lease from the Illinois Central R. R. Co. about 14,000 acres, in the east half of Township 12, Range 12 W., in Marion county, Alabama, and owns other lands, of which about 1,000 acres adjoin this leased tract, making a total area of about 15,000 acres, all of which is underlain by the coal-seam upon which the company is operating. This seam is nearly horizontal; and a ravine, diagonally crossing the tract, exposes the outcrop on either side for about 2 miles. The territory has been so divided that nearly the whole of it can be worked out by two collieries. The mines at Brilliant were opened in the fall of 1898, and shipments began in the following spring. The original plan was to furnish steam-coal for locomotives to the Illinois Central R. R. Co.; and upon this expectation the investment of capital was made. The field was entirely new; and the softness of the coal at the outcrop induced the belief that it could be very cheaply mined. A contract for the delivery of a large quantity of coal to the railroad was accordingly executed. But with the advance of&apos; the entries to increasing distances from the outcrop, the coal proved so hard that it could no longer be drilled with a breast-auger; and the expense of mining became so great that the contract for cheap steam-coal had to be canceled. It became evident that the work must be done with machinery and explosives, if it could be profitably done at all. On the other hand, the excellent quality of this coal opened, at the same time, a possible market not specially contemplated at the outset—namely, that of a first-rate coal for domestic and general uses. Since no other deposit of such coal was known to exist on the line of the Illinois Central, or any other railroad

Jan 1, 1907

By N. Tiner

IN an article on magnesium and its alloys, Gann and Winston1 stated that manganese has a limited solubility in the liquid state. W. Schmidt2 showed a diagram according to Joseph Ruhrmann indicating that the solubility of manganese in liquid magnesium falls from about 2.65 per cent at 790°C. to about 0.5 per cent at 695°C. The curve was extrapolated to show zero solubility at the melting point of pure magnesium (Fig. I): This work suggested that at the lowest manganese contents it was not possible to detect either a eutectic or the formation of a solid solution, so that manganese was stated to be present in the structure as large individual crystals. Two years after the presentation of these results, Gann3 brought evidence to show that some manganese is capable of dissolving to form a solid solution, any excess of manganese present then assuming chiefly the form of small blue-gray particles scattered throughout the primary magnesium crystals, occasionally in clusters but seldom at the boundaries. He presented micrographs of cast alloys containing o.1, 0.4 and 1.0 per cent manganese that show a small amount of coring around the individual particles due to solid solution, and indicate that the location of the manganese particles is closely associated with the original dendritic structure of the primary crystallization. He also pointed out that the amount of manganese that can be dissolved in magnesium depends on the amount of other alloying elements present, the effect of the second alloying element being to decrease the amount of manganese retained in the alloy. E. Schmid and G. Siebe14 have determined the solid solubility of manganese and its variation with temperature by means of precision X-ray diffraction measurements. They found that the solubility is 3.4 per cent at 645°C and decreases to practically zero at 200°C. It is apparent that the X-ray diffraction measurements of Schmid and Siebel are not in agreement with the results of Ruhrmann as presented by Schmidt. This disagreement, and also the lack of data on magnesium-aluminum-manganese and magnesium-zinc-manganese systems, led the author to the present investigation, to determine accurately the liquid solubility of manganese and its variation with temperature. EXPERIMENTAL METHOD The experimental method for making solubility determinations consists of saturating the molten magnesium or the alloys with manganese at various temperatures and analyzing the dip samples taken from these melts. Melting is carried out in a cylindrical steel pot heated by an electric resistance furnace. The pot had a metallic outside coating to protect the steel against oxidation, and a graphite inside lining to prevent the contamination of the melt by prolonged contact with iron. The inside diameter of the pot was 4 in. and the depth 12 inches.

Jan 1, 1945

By Akira Ishizu, Nobuo Matsui, Tatsuya Nagahama

In the concentrator of Kamioka Mine, lead-zinc bulk differential flotation is practiced. It results in three kinds of thickener over- flow, namely; tailing, lead concentrate and zinc concentrate, which are discharged as wastewater. Since these three kinds of overflow differ from each other in water quality, they are separately recycled to appropriate processes based on their water quality. The tailing and the lead concentrate thickener overflow are directly recycled to their respective suitable processes. However, as the zinc thickener overflow contains Cu(CN)3--, ZnS, CdS, CN-, xanthate and frother, the total zinc thickener overflow cannot be recycled at one time to any one process without creating harmful effects. Consequently, all the ingredients in the zinc thickener overflow other than CN- are floated by Ion-Precipitate-Ultrafine-particle flotation, using Nagahm flotation machine. After this treatment, the zinc thickener overflow, containing only CN-, is effectively recycled to the lead-zinc differential flotation circuit. Thus the integrated recycling of waste-water greatly reduces environmental problems, and in addition it generates a sizeable profit by improving overall mill recovery, and permitting the reduction of reagent consumption.

Jan 1, 1976