Search Documents

By Thomas Wright

No symposium on die casting could be complete without consideration of the methods of formula and impurity control. No consideration of control would be complete without discussion of that new tool of the analytical chemist and inspector, the quartz spectrograph. Just as there is an increased appreciation of the possible applications of the die-casting process and of die castings, so too is there, slowly but surely, of the spectrograph. At present the role of the instrument might well be compared with that of brass or magnesium die castings. Neither is as widely understood or known as they will be. Product specifications are increasing and are getting more explicit and often more rigid. The designer, metallurgist and production engineer or superintendent will be forced to depend more and more on the chemical laboratory. Sampling, as well as analyses, testing and inspection problems will grow. The chemical laboratory must meet its increased responsibility and use of the spectrograph will become more common. Advantages of increased precision, greater speed, lessened labor and often lower costs cannot be ignored. It will be the purpose of this paper in part to outline the respective fields of chemical and spectrographic analyses and to indicate where one may overlap the other and in part to indicate certain possible sources of contamination of zinc-base die-cast alloys in particular.

Jan 1, 1935

By R. F. Marande, R. S. Busk

THE magnesium-aluminum-zinc system contains most of the magnesium-base alloys used commercially, although in practice the ternary, alloys are usually modified by the addition of a small amount [ ] of manganese. Table I contains the magnesium-base commercial sand-casting alloys most widely used throughout the world, together with their typical tensile properties. These alloys may be regarded as a single family of varying aluminum and zinc content, disregarding manganese. A concise means of presenting data for them is by means of iso-property lines plotted on triangular coordinate paper. Constitutional, casting, and mechanical properties are presented in this manner. The data are given with the object of providing reference material, and to aid in the choice of a commercial alloy to serve a particular purpose. Detailed, critical analysis of the commercial alloys has been covered in a previous paper.1 [ ] All alloys reported were made in 15-lb. melts, superheated to 1700°F. for 15 min., cooled to 1400°F. and poured in sand molds. The test bars produced had a ½ in. reduced section and were about 6 in. long. Except for the data represented in Figs. I and 3 the alloys used were of commercial purity and contained 0.1 to 0.2 per cent Mn in addition to the aluminum and zinc. CONSTITUTIONAL DATA Under the heading of Constitutional Data are included all known data on con-

Jan 1, 1946

By George Smith

The Australian Broken Hill Consols mine is situated within a third of a mile eastwards of the famous Broken Rill Proprietory mine; but, so far as has yet been proved, the respective lodes have no connection whatever. The Proprietory line of lode, striking N.E. and S.W., is coincident with the bedding-planes of the inclosing gneiss, and, according to Mr. E. F. Pittman, A.R.S.M., government geologist, is undonbtedly a saddle-formation. This opinion, which met with much opposition at the time it was advanced, is now, I understand, being generally confirmed as the work of development opens out fresh areas for observation along the line of lode. The lode is of immense thickness—in places over 300 feet and though it has been found to contain sufficient quantities of secondary silver compounds to yield phenomenal outputs of silver, its principal constituents are various lead and other ores, and it would appear more correct to regard it as an argentiferous lead-deposit than as a silver-lode proper. The Consols lode differs from its gigantic neighbor in every respect. With an average thickness of not more than 18 inches, it has been worked along its course for upwards of 1300 feet, and at every point yet explored has been found remarkably well-defined and persistent. With a strike E. and W., it cuts obliquely across the bedding of gneiss and schist, continuing uninterruptedly through various bands of eruptive amphibolite. The dip, which is to the south, ranges from 24 near the surface to nearly vertical in the lower levels; but the alteration is not regular, as in places the lode is almost flat, and this at a vertical depth of over 300 feet. These changes of inclination have had no effect on the ore-deposits, which, as I shall endeavor to show, have been governed entirely by " cross-

Jan 1, 1897

By Elmars Ence, Harold Margolin

The partial isothermal section of the Ti-Cu-Zr system at 750°C has been studied. The crystal structure of Ti2Cu has been detevnlined as tetragonal and when expressed as face-centered tetragonal, a = 4.164, c = 3.611 A, and c/a = 0.867. TITANIUM systems in which ß-titanium decomposes eutectoidally into a and a compound rather readily are known as active eutectoid systems. Recently in active eutectoid alloys based on the Ti-Cu system, and containing additionally A1 and Zr, it has been found that zirconium may produce both moderate weakening and marked strengthening at elevated temperatures.' In order to obtain some insight into the behavior of zirconium, an attempt was made to determine whether compounds of the type Tix Zr and TixZryCu exist. Only results of the Ti-Zr-Cu studies are reported here since data on Ti-Zr alloys will be presented in a separate publication. EXPERIMENTAL PROCEDURE Alloys were nonconsumably arc melted in argon atmosphere as 15-g buttons, prepared from materials of the following purities: Bureau of Mines electrolytic Ti — Bhn 63 OFHC copper Reactor Grade Zirconium Bhn .C 150 Prior to alloy preparation the electrolytic titanium was premelted to avoid excessive spattering of the charges during melting. The weight losses during melting did not exceed 1 pct of the total weight of the charge. The alloys prepared are listed in Table I together with analyzed compositions. in cases where they were determined. Specimens for heat treatment were wrapped in molybdenum sheet, annealed in argon-filled quartz capsules, and quenched by breaking the capsules under iced brine. About 1 to 2 sec are required to remove the capsule from the furnace, drop it into the iced brine and break it. Because of the insulation effect of the quartz, this delay in quenching should not produce a large drop in temperature. In many instances, no difference or little difference has been detected between the same specimen quartz capsule quenched or directly quenched in vacuum by an impinging stream of water.' Ti-Cu-Zr alloys were homogenized for 48 hr at 825°C prior to annealing at 750°C. Annealing for 5 days at 750°C produced the same results as 11 days at temperature and it was therefore assumed that 5 days was sufficient to establish equilibrium. Titanium-copper alloys were homogenized for 40 hr at 900°C prior to heat treatment for 6 days at 750°C. Specimens for metallographic examination were electropolished and etched with the following solution:

Jan 1, 1962

By M. J. R. Morris

THE year 1939 has seen the iron and steel industry driving for efficiency with unabated zeal. "Efficiency" is here used in the sense of enabling the customer to do more with less, either supplying him with more economically priced steels or with higher priced steels that will do a job more economically. The plain carbon steels have been improved tremendously in quality be- cause of recent control tests. All steel companies have been urged to hold to .closer chemical control, closer standards, soundness, and more control on grain size, and now attention is being directed to closer control of hardening properties. Better control of open- hearth operations undoubtedly will result in an increase in the application of special carbon steel. Further, with a better understanding of quenching, the present trend to study the quenching of this class of steels will be ex- tended. These steels will then be used for purposes to which they are best suited. Utilization of special carbon bars and large shapes seems to be developing less slowly than special car- bon in the form of strip. There are many reasons for this and the future development of this trend will be important. Continued development of the manufacture of parts from strip and sheet to replace forgings, and of formed; structural members such as channels or welded pipe, is notable. Special carbon sheets with nonaging properties have been produced during the year; they maintain a higher degree of ductility over a longer time and are less sensitive to the changes which took place in the former product when stocked.

Jan 1, 1940

By J. B. Mackintosh

The quantitative determination of copper, by means of electrodeposition, offers so many advantages, that it is to he preferred, when properly executed, to 611 other methods for ease and accuracy. The object of the present paper is to give the results of a number of experiments made during the past few months, and to indicate some sources of error, which must be avoided in order to attain the necessary accuracy. In 1867, C. Luckow, in competition for a prize offered by the directors of the Mansfield Copper Works, submitted the following

Jan 1, 1882

By J. C. Karcher

GEOPHYSICAL methods have been more extensively applied to prospecting for oil during 1936 than at any previous time. Their use has been extended to include al- most every oil and gas producing area in the United States. More than ten magnetometer parties, more than nine gravimeter parties, more than five electrical surveying crews, more than fifty torsion balance parties, more than two hundred seismic reflection parties, and several refraction parties were- operating in the United States throughout the year. A tendency has been noted to abandon the use of the pendulum for geophysical prospecting in the oil fields and to increase the use of the

Jan 1, 1937

By A. Hansson, G. E. Tardiff

WHILE it is generally known that cold-worked low-and medium-carbon steels exhibit substantial increases in tensile rupture ductility with increased deformation velocity172 (up to the von Karman limit), the observations for annealed or normalized steel do not permit simple generalization. Various investigators, for example, have reported both small increases1,3 and small decreases4,5' in rupture ductility with increased rates of deformation of normalized low-carbon steel. The purpose of the present note is to report on the dependence observed for strain-aged steel since preliminary work here indicates that strain aging results in the development of a consistent type of behavior that is understandable in the light of current knowledge of the lower yield dynamics for steels which deform inhomogeneously.6 This realization throws additional light on the influences responsible for the behavior of normalized steel. The results presented here were obtained for a 0.21 pct C, 0.012 pct N sheet (0.012 in. thick) steel which was received in a temper-rolled condition (approximately 3 pct reduction in thickness after process annealing); the as-received material had a spherodized structure with a ferritic grain size of ASTM 8. The material was selected for testing after 6 months room temperature aging, at which time the static lower yield and ultimate tensile strength measured 79 and 82 kpsi, respectively. ASTM 2-in. reduced section, 1/2-in.-wide specimens were used in smooth bar tests and 3/4-in.-wide specimens containing two 60-deg opposed edge notches (root radii = 0.002 in.) were used in notched bar tests. To facilitate strain measurement, the smooth bars were blued with ink and marked at 0.1-in. intervals along the gage length; the notched

Jan 1, 1968

By Charles A. Schffer

Several months ago, some specimens of the minerals occurring at the Etta tin mine, Dakota, were received at the laboratory of the Cornell University. On examining the heavy brownish-black portion, which I presumed was the tin-stone, I was surprised to find only a faint indication of tin. Further investigation showed the mineral to be tantalite. On searching carefully all the fragments received, a considerable quantity of that mineral was found, and only a single streak of cassiterite, which was attached to a mass of spodumene. Another lot of specimens, from the same locality, consisted of

Jan 1, 1885

In discussing Mr. Keller's paper, I quoted the results obtained by Mr. Allan Gibb, correctly crediting them to Mr. Gibb, with due reference to the report in which they were published. But in the table immediately following, and in my further remarks, following the table, I find that, by some clerical or other error which I cannot, after the lapse of time, explain, I spoke of Mr. Gibb as Mr. "Dean"—a metallurgist who had written on a related subject, but not on the point I was discussing. In short, my reference throughout was to the work of Mr. Gibb; and by reading a Gibb " for a Dean " in all places on pp. 832 and 835 where the latter name occurs, my remarks will be brought into accordance with my intention, and with the facts.

Jan 1, 1901

By E. Gybbon Spilsbury

Everybody who has had his attention turned to the gold-deposits of the Southern States, is acquainted with the undisputed fact of the existence, at least in the Carolinas and Georgia, of enormous areas of gold-bearing rocks. Long before the discovery of the precious metal in California, gold-mining on a very extensive scale mas a well-estab-

Jan 1, 1887

By Percy A. Robbins

The central power-station of the De Beers Consolidated Mines, Ltd., was designed and built under my supervision about five years ago. Since no detailed description of this plant has ever appeared, it may possess sufficient interest to arrant its publication, even at this late date. Although some additions may have been made to the plant, the following account, prepared from my notes, and accurate up to May, 1905 (at which time I severed my connection with the De Beers Company), will, I think, be found substantially correct. Certain local conditions governing the design of this plant should be stated first. IT. General Considerations. The climate is hot and dry. The region around Kimberley is arid and water is very scarce. The supply obtained from the mines contains so much material in solution that it is unfit for use in boilers or condensers (although tests recently made with a water-softening plant, built by Hans Reisert, of Germany, would indicate that water thus treated is suitable for boilers). And the amount of water required for concentrating about 30,000 tons of ore per day is so large that the question of adequate water-supply for this power-station had to be carefully considered. The rainy season extends from December to April, and the rainfall averages about 15 in. per year. Droughts are frequent; and in some years there is scarcely any rain at all.

Jan 1, 1909

By Douglas M. Smith

Silver-gold ratios were studied at the Tayoltita epithermal vein deposit using channel sample, channel sample line, stope, ore body, and vein sample populations. The ratios are highly variable among individual channel samples (25:1 to greater than 500: 1) with both high and low values randomly distributed within ore bodies and veins. Whole vein ratios for the 14 most important ore producing structures range from 44: 1 to 105:1, and show zonal distribution relative to two small granitic stocks, low values closest to the intrusives. The zoned nature of the deposit suggests that the stocks, apophyses of an underlying batholith of late Eocene age, were the heat engines which powered the hydrothermal system responsible for ore deposition.

Jan 1, 1980

By E. L. Dougherty, J. W. Sheldon

Using the numerical techniques shown in this paper it is possible to compute the simultaneous dynamical behavior of multiple fluid-fluid interfaces in two dimensions. Hence, fluid-fluid inter face models of several oil recovery processes can be constructed which allow prediction of the effect of fluid flow in two dimensions on the behavior of these processes while taking into account various physical effects, such as saturation gradients, phase changes and thermal stimulation. Techniques for constructing fluid-fluid interface approximations for several oil recovery processes are reuiewed. The validity of these techniques is established by comparison to experimental results. The availability of a computer program for computing the behavior of multiple fluid-fluid interface problems makes the use of potentiometric models uneconomic. The results indicate the areal sweep efficiencies obtained from potentiometric model studies at high mobility ratios may be somewhat optimistic. The results also indicate that the areal sweep efficiency curves obtained at high viscosity ratios 2—4 using miscible fluids in porous media are misleading and that considerable care must be taken in defining the mobility ratio for a displacement process, especially for miscible fluids. INTRODUCTION Many of the methods used to estimate areal sweep efficiency assume that the oil recovery process can be represented by one or more fluid-fluid interfaces. When the mobilities of the displaced and displacing phases are assumed equal, this quantity can be computed using analytical mathematical methods.l.2 For non-unit mobility ratio, experimental methods based upon the fluid-fluid interface concept include potentiometric and electrolytic blotter models. Scaled models of porous media have also been used to study this problem. Fay and Prats3 and Aronofsky4 used numerical techniques to compute breakthrough sweep efficiency, but neither of these studies were extended beyond breakthrough. Numerical techniques which have been developed for solving a general fluid-fluid interface problem are presented in a companion paper.5 These techniques have been incorporated into a program for a large-scale digital computer which can treat simultaneously the dynamical behavior of as many as six fluid-fluid interfaces. Thus it is possible to simulate the behavior of several oil recovery processes taking into account such effects as saturation gradients. Techniques for representing several oil recovery processes by fluid-fluid interfaces are presented. Processes considered are conventional water flooding with and without a mobile gas phase, hot water flooding, miscible flooding and enriched gas drive. Other processes, whose effects could be studied by this technique, but are not considered in detail here, are underground combustion and steam injection processes and various slug processes such as gas-water injection and alcohol-solvent processes. Theoretical results obtained with single interfaces for mobility ratios of 0.25, 1, 2, 4, 8, 16, 32 and 64 in a repeated five-spot are compared to experimental results for this geometrical configuration obtained using miscible fluids and conductive analogs. Predicted recovery curves for water flooding in a repeated five-spot are compared to experimental results reported in the literature. Example calculations are shown for a conventional water flood in the presence of a free gas phase and for a hot-water flood. MATHEMATICAL PRELIMINARIES We assume that the rock matrix is homogeneous with constant thickness, absolute permeability and porosity. The fluids are incompressible. We also neglect the effects of gravity.

Jan 1, 1965

By Michael Richings

Although the role of slope stability has not changed, there have been changes in the mining industry which affect the geotechnician engaged in slope stability studies. The deposits currently being mined or evaluated are technically difficult , capital intensive, and economically marginal. In addition, many mining companies are now either controlled by oil companies or are financing projects through bank loans. The mining investor or decision maker is, therefore, often more sophisticated financially, but less sophisticated in mining terms. The impact of these changes will be to force the geo- technician and mining engineer to attempt to quantify risk and financial implications of a slope design. In conclusion, this paper outlines several questions which mining engineers should be asking those engaged in geotechnical studies and indicates the necessity for the mining engineer and geotechnician to work together and quantify the financial risk associated with a geotechnical design.

Jan 1, 1983

The practice of fine-grinding is now being so succeesfully carried on in some fields, notably in West Australia, and its advisability has been so frequently pointed out,l that the matter in this paper is not put forward as new; its chief object being to call attention to the importance of fine-grinding in the treatment of comparatively low-grade oree. I' have been engaged daring the last five years in the cyanide-treatment of ores in the Ohinemuri district (North Island), New Zealand, and I consider that, in the near future, extremely fine-grinding (almost sliming) will become a very im-

Jan 1, 1906

By John Birkinbine

The press, trade publications, and special circulars, some elaborately illustrated, have been liberally employed within recent years in this country, to set forth the advantages of various locations as industrial centers, having as a basis the possibility of profitably producing pig-iron at these proposed centers: and special stress has been placed upon opportunities believed to exist at certain points for making iron of a quality suitable for the manufacture of Bessemer steel. The remarkable statements and prophecies made in some of these publications, have suggested the present paper, treating of the influence which location exerts upon the special industries named.

Jan 1, 1893

By Wolfgang Pietsch

Prior publications have shown that the structure and characteristics of direct reduced iron produced by direct reduction from iron ores or iron ore pellets depend on many parameters which include process variables, such as, reduction temperature, reduction gas composition, and type or origin of the raw material. Most of the published literature deals with direct reduced iron produced in the laboratory at theoretically interesting but commercially uneconomical or technically impossible conditions. Much of the work was carried out in pure carbon monoxide in pure hydrogen, or in such mixtures of carbon monoxide and hydrogen which are of no commercial interest. Other results were obtained at temperatures which are too high and would cause sticking in large scale plants. For this reason, work was initiated by Midrex Corporation to investigate the influence of raw materials and reduction temperature on structure and characteristics of direct reduced iron. The composition of the reducing gas used to prepare the samples for this study produces results corresponding to those obtained with a typical commercial gas. The temperatures at which reduction was carried out are in a technically feasible range. This paper reports on the results.

Jan 1, 1979

David T. Day, Washington, D. C.: The paper of Mr. Adams is chiefly valuable because it emphasizes the ease with which petroleum can migrate in the earth's crust. Concerning this migration, I have little faith in the rôle of water as a carrier of gaseous or liquid hydrocarbon, suspended or mixed in the water in any way. My lack of faith is due to observation of

Jan 1, 1903

By A. C. Boyle

PaGE I. Introduction.........68 II. Location of the District,....... • 70 .. III. Stratigraphy...........73 Description of the Rocks.......73 Triassic Eruptives (Andesite Flows and Tuffs) ....73 Triassic Sediments (Shales and Slates)..75 Areal Geology ............75 Structure...-.......76 Folds............. 76 Faults..........79 Shear ...........80 Intrusives..........81 Alaskite Dike.........81 Andesitic Intrusion.......82 IV. PetrogRaphy of thE Rock Types......83 Andesite Flows.........84 Tuff 8...........84 Andesite Tuff........84 Rhyolite Tuff.....-.......85 Alaskite-Porphyry.......89 Andesite Dike........91 V. Description of the Mines......92 VI. Metalliferous Deposits ........ 95 Character of the Ores...........97 Mineralogy of the Ores.......97 Metallic Minerals.......97 Microscopic Character of the Ores...98 Secondary Enrichment....... 103 Genesis of the Ores ...........104 VII. The Sulphate Deposits.......109 Gypsum ..... HO Anhydrite......... ,... 110 Barite............ 110 Origin. with special reference to Gypsum....111 VIII. Summary.............. 113 IX. BIblYogRaphY.............114

Jan 1, 1915