Search Documents

By H. V. Kinsey

"IntroductionTITANIUM is probably the most widely publicized metal today. Much has been written, both in the lay press and the technical press, about its properties and potentialities. In view of the fact that Canada possesses large quantities of titanium-bearing ore, and could conceivably become a major producer of metallic titanium, it was felt that a paper dealing mainly with the physical metallurgy of titanium would be of interest to this Institute. This paper is concerned chiefly with the useful properties of titanium and its alloys and the fundamentals governing the modification of its properties by alloying.Physical Properties of TitaniumTitanium belongs to a family of metals that have been termed 'gas sensitive' (I), because their mechanical properties are altered by certain gases which they readily absorb and retain. Other metals of this group are zirconium, hafnium, vanadium, columbium, tantalum, and chromium. Titanium has a strong affinity for oxygen and nitrogen and once it has absorbed these gases they cannot be removed either by melting in vacuum or by any degassing agent. These gases, when present in excess of about half a per cent oxygen plus nitrogen, render the metal brittle and useless as a structural material.Some of the typical physical properties of titanium are listed in Table I along with those of common structural metals for comparison."

Jan 1, 1953

By Paul W. McGann

THE MINERAL INDUSTRIES had a near-record year in 1950, as rising industrial activity in general, greatly accentuated by the outbreak of hostilities in Korea in midyear, called forth increasing supplies of mineral fuels and raw materials. The aggregate value of mineral production was second only to that in 1948, and the aggregate physical volume was exceeded only in 1948 and 1947. Lower coal production accounted for the failure to surpass these earlier years. Growth of production was fairly constant throughout the year, especially for crude petroleum; its physical output for the year as a whole exceeded that of 1949 by 7 percent. According to Federal Reserve Board indexes, other relative gains were 16 percent for coal, 9 percent for fuels in general, and 17 percent for metals. The increase for mining in general was of the order of 10 percent. This was not quite as large as the general increase in industrial production but clearly reflected the total-industrial trend (see fig. 1).

Jan 1, 1953

The organization of this department is as shown in the following chart:Chief Mechanical EngineerPowerGenerationWorkshopsNew ConstructionMaintenanceTransportCommunity ServicesMineMillSmelterDesign and OfficeOrganizationThe functions of each section will be described separately.MAINTENANCE UNDERGROUND DEPARTMENTThis section covers all mechanical equipment underground as well as fans and winders on the surface, the headframes, and conveyors from the shaft to the crude ore bins. As has been descrIbed, No. 2 Ore shaft was opened up to the surface and a new headframe and receiving bins were erected, and when the new lead crushing and screening plant was constructed and ready for operation, the rope sheaves...

Jan 1, 1953

By R. R. Wells

For several years the Klukwan deposit near Haines, Alaska, has attracted interest as a potential source of iron. Limited field and laboratory investigation has indicated that the deposit contains a large amount of Iron that is recoverable as high-grade concentrate. This report summarizes the results of laboratory beneficiation testing of the Klukwan ore, as represented by six samples submitted to the Alaska Experiment Station of the Bureau of Mines, Juneau, Alaska, Iron is present in the ore as a fine-grained magnetite associated with a pyroxenite type basic rock.. Satisfactory magnetic-separation procedures were developed for the production of concentrates assaying more than 60 percent Fe and 2 to 4 percent Ti02. During the investigation many data were obtained and compiled, but for convenience and clarity data of secondary importance have been omitted or condensed; only the more pertinent test results are discussed in detail.

Jan 1, 1953

By W. M. McCardell, W. O. Winsauer, M. Williams

The mechanism by which an electrical potential difference is developed between two salt solutions separated by shale is shown to be a consequence of the electrical double layer of the shale surfaces. A mathematical derivation is presented to show -the dependence of the potential on the shale characteristic.? and on the concentration of the salt solutions. The equations developed describe adequately the potential-concentration behavior of a long shale core. The equations also describe the variation of potential of sand-shale mixtures with variation of clay content. Ion adsorption i* an important factor in he developments of the surface charge on the shale. and electrical resistivity and ion transference number data are emlployed to estimate the increase of surface charge with concentration. Since the potential is shown to be dependent on the characteristics of the particular .system. water salinities estimated from the potential log by previously proposed methods may be low in some rase;. INTRODUCTION That the electric well log exists today may he attributed to the ingenuity of the Schlumberger brothers who adapted to the logging of wells techniques which were originally developed as surface prospecting methods for the location of ore bodies Empirically it was found that the potential curve of the electric log usually gave values for clean sands which were negative with respect to the values for shales. It was suggested that the potential was responsive to porosity. It was postulated in explanation? that the potential was the sum of a streaming potential, which differed for sands and shales, and of an "electro-chemical" potential of undetermined origin. Mounce and Rust in 1943 showed that the streaming potential is small in most cases and that the potential is generated by a process in which shale and a salinity difference play-essential party. Dickey.:' in the same year, concluded that the potential is dependent upon adsorptive properties of reservoir rock. Wyllie in 1949. and Wyllie and Patnode, in 1950, measured the potential-: between two salt solutions separated by barriers of either naturally-compacted or artificially-compacted shales and concluded that the potential can be expressed by where E is the potential R is the gas content F is Faraday's constant T is the absolute temperature are the activities of the two uni-univalent solutions These authors postulated that shale. in the ideal case is impermeable to the migration of negative ions. Any potential less than the "ideal" shale potential was considered to be due to imperfections in the shale barrier. Although the studies by Wyllie and Patnode of the development of the shale potential are fairly recent. investigators in fields other than well logging have discussed the mechanisms responsible for analogous potentials over a period of several decades. Although it is evident that much thought has been devoted to the question of the origin of the potential observed in wells, it is also apparent that all of the explanations presented to

Jan 1, 1953

By A. R. Gregory, M. R. J. Wyllie

The literature reveals that scant attention has been paid to the systematic experimental determination of the formation factors of unconsolidated porous media. No experiments appear to have been made on the effect of increasing cementation on the formation factor of an initially unconsolidated porous medium. Measurements have accordingly been made of formation factors as a function of porosity for aggregates of spheres in the porobity range 12-56 per cent and of cubes, cylinders, discs and triangular prisms in the porosity range 30-45 per cent. The results are examined in the light of the theoretical equations of Clerk Maxwell. Fricke and Slawinski. Aggregates of unconsolidated spheres and beach sands have been artificially cemented with silica and the formation factor-porosity relationships determined. A theory is outlined which seeks to explain the results obtained and which postulates that formation factor and porosity data for consolidated sandatones may be used to determine the original porosity of the unconsolidated sands from which the consolidated sandstones were derived. It follows also that for consolidated sandstones F' = C where F is formation factor, fractional porosity and C and k are constants. INTRODUCTION All schemes of electric log interpretation implicitly or explicitly require the use of formation resistivity factors or? as they are now generally called. formation factors. 'The originator both of the concept of formation factor and of the use of formation factor data in electric log interpretation was Archie.' More recently it has been suggested that formation factors are of value in describing fluid flow in porous media. A full discussion of this problem together with adequate reference.: has been given by Wyllie and Spangler.' In spite of the theoretical and practical importance of the subject, there appear to be remarkably few basic formation factor data in the petroleum literature. A wider search reveals that this situation is nut confined to the literature of the to industry. at various times over the last century, attempts have been made to compute the theoretical relationship between the formation factor and porosity of simple systems of unconsolidated particle.. However. the formulae derived are not all identical and the experimental evidence adduced in support of each i; not wholly convincitng. Most of the experimental work has been carried out on system. of unconsolidated spheres, although some attention has been given to systems of spheroids and cylinder. Other simple shapes have received neither theoretical nor experimental investigation. The writers feel that a better understanding of the formation factors of complex systems of practical importance requires a firm foundation of reliable experimental data applicable to simple systems. Accordingly, they have reviewed the relevant literature and have determined experimentally the relationship between the formation factor and porosity of unconsolidated aggregates of particles of regular geometrical shapes. Some experiments have also been carried out to investigate the effect of cementation on the formation factor-porosity relationship. PREVIOUS WORK Although the term formation factor was not used. the relationship between the resistivity of a solution containing dielectric solids and the resistivity of a similar solution not containing solids is an old and important problem. The formation factor of a system of dispersed spheres as a function of porosity was considered by Clerk Maxwell. Maxwell arrived theoretically at the following expression: where F is formation factor and fractional porosity. Lord Rayleigh' also examined the problem of the formation factor of systems of spheres and cylinders and concluded that for spheres Clerk Maxwell'.; expression gave a value of F whirl]. at low porosities particularly, was too small. However,

Jan 1, 1953

By G. Bassi

RECENTLY Wallbaum¹ found that copper wires with different degrees of deformation up to 98.7 pct area reduction recrystallize giving a [112] texture, while deformation over 98.7 pct gives either a [l00] texture at low temperatures or a [1ll] texture at high temperatures. Furthermore it was found that the recrystallization temperature as a function of deformation up to 98.7 pct decreases as expected, but increases over that deformation. Wallbaum concluded that the different textures have different recrystallization temperatures. The [112] texture has the lowest and [Ill] the highest. At the same time Bassi² found that for high deformation (over 99 pct area reduction) and for an annealing temperature of 400°C, the [l00] texture first forms and with prolonged annealing time the [12] texture appears through grain growth. This secondary texture does not appear if the wire is annealed at 1000°C before the deformation. From these two papers it might be concluded that the [I12] texture can appear either as a primary or as a secondary texture after annealing. The texture formed in a special case depends on the previous history of the wire. Probably the texture of the wire prior to the last deformation is important. To investigate this, wires were produced by adequate deformation and annealing to give a [l00], a [112], and a [lll] texture. The wires then were given a series of different deformations and were annealed at various temperatures, after which the textures were studied. Experimental Work The copper used was electrolytic tough-pitch (Cu 99.90 pct and 0, 0.04 pct). Three wires with the different initial textures were made in the following way: The [l00] and [112] by drawing a 16 mm rod to 1 mm and annealing it 16 hr at 200°C and 2 hr

Jan 1, 1953

By J. D. Hanawalt, W. H. Gross

Magnesium has long been known as the lightest of our engineering metals. This metal, silvery white in color, has a specific gravity of only 1.74. Aluminum, the next lightest structural metal, is 1 ½ times heavier; zinc is 4 times heavier; iron and steel are 4 ½ times heavier; and copper and nickel are 5 times heavier. Magnesium does not occur in the free state but is very abundant in nature, constituting 2.5 pct of the earth's crust in the form of various ores. It is the third most abundant structural metal, being exceeded only by iron and aluminum. Magnesium is unique, however, in that in the form of magnesium chloride it also exists in the oceans. Sea water is the source most widely used for production in the United States but magnesium is also commercially produced from magnesite, dolomite, and other ores as well as from certain inland brines. The vast quantity of magnesium existing in the waters of the oceans can be visualized when it is realized that the removal of one hundred million tons per year (the approximate annual steel production in the United States) for a million years would reduce the magnesium content of sea water only from 0.13 to 0.12 pct, providing no more magnesium had washed into the sea in the meantime. Not only is magnesium potentially very abundant but it is in addition a very versatile metal and can be shaped and worked by practically all methods known to the art of metal working. It can be cast by sand, die, and the various permanent-mold methods;

Jan 1, 1953

By Fred H. Poettmann, J. K. Welchon, A. F. Bertuzzi

A series of gas-lift tests was made which verified conclusions reached from previous studies and which showed that gas-lift performance could be calculated if reasonably accurate data on the producing characteristics of the well are available.' The test installation is described. Its essential features consisted of a rate-of-flow controller to regulate the input gas and an auxiliary string of small diameter tubing to conduct the input gas to the point of injection in the eductor tubing. In general, it was shown that for continuous gas-lift operation, injection should be as deep as possible consistent with available gas pressure and rate of production desired. Calculated curves are presented which completely characterize the gas-lift performance of the well tested. INTRODUCTION A correlation based on field data from a large number of flowing and gas-lift wells, covering a wide range of oper- ating conditions, was developed which permitted the logical design and prediction of the performance of continuous gaslift installations.' The procedure made it possible to calculate the depth, pressure, rate at which to inject gas, horsepower requirements, and the effect of production rate and tubing size on these quantities. As a result of these calculations certain significant facts were brought to light or re-emphasized. The presence of efficient ranges of operation and an optimum injection depth for a given rate of production were shown to exist as well as the fact that the lower the tubing pressure the less the horsepower requirements to lift the reservoir fluids. The fact that the gas lift performance can be predicted by calculation does not mean that any given installation will perform over the entire range predicted. Many of the conventional continuous gas-lift installations will not permit operation over the entire range predicted by calculation (particularly in the efficient range of operation) because of the performance characteristics of the installation. Consequently, field tests were initiated for the purpose of investigating and arriving at a simple continuous gas-lift installation which would operate under all conditions predicted by calculation. The first series of tests involved the use of mechanically operated valves. These valves were slip-joint type valves which are opened and closed by lowering or raising the tubing at the surface by means of a hydraulic jack. These valves were chosen because it was hoped that they could be opened or closed at will and did not depend on the gas pressure in the annulus or the pressure of the fluid in the tubing for their operation. Unfortunately, the valves did not operate satisfactorily and it was imossible to open or close each valve at will. Some limited data were obtained, however, which verified the predicted benefits resulting from the use of lower tubing pressures. In the next series of tests the valves were removed and the gas was injected from the annulus through a 14/64-in. orifice equipped with a reverse check valve. A packer was set below the valve to seal off the space between the 2-in. tubing and 5-in. casing. The injection point was located at 3,810 ft. This arrangement provided satisfactory mechanical operation. However, it was impossible to obtain low rates of liquid production at low tubing pressures as predicted by calculation. A minimum gas injection rate existed below which steady flow was impossible. Liquid pro-

Jan 1, 1953

By A. B. Kinzel

IT is with sincere appreciation and a deep sense of responsibility that I accept the honor of delivering the Howe Memorial Lecture. In our time metallurgical research has delved into phenomena ever more complex in character, so that much of this work must be done by organized teams. We, of the Union Carbide and Carbon Research Laboratories and the Electro Metallurgical Co., are truly a team and the lecture which is to follow is due largely to a few of the outstanding members of that team here cited and well known to you in their own right: John Lamont, whose work deserves special recognition, Walter Crafts, William Forgeng, William Binder, Robert Fowler, and David Swan. Thus it is a fitting pleasure to accept this honor for the research institution which I represent. Henry Marion Howe was truly inspirational and his breadth of view was such that he could use either the method of rigid proof or implied mechanism to further the broad understanding. But perhaps his outstanding characteristic was his sound judgment and his ability to weigh observations. The following is replete with observations and judgment as to their implication. We would like to feel that it is the type of dissertation which Howe, himself, would have enjoyed. Chromium carbides in stainless steel have, in a sense, been a key to the progress of the stainless steel industry. Brearley's first stainless steel, containing approximately 0.30 pct C, was successful because it differed from previous Fe-Cr alloys in that the carbides were present in such amount and form as to provide the stainless and cutting properties. Again, the 12 pct Cr die steels with a carbon content of 1.5 pct or more achieved their properties by virtue of the form and distribution of the chromium carbides. In the straight chromium steels with from 12 to 25 pct Cr, chromium carbide amount and distribution are once more the determinants with respect to physical properties and corrosion resistance. In each of the cases just cited the role of the carbide is in essence similar to that of iron carbide in carbon steel and this story is so well known that we need not dwell on it. In the austenitic stainless steels, the chromium carbide plays only a minor positive role with respect to mechanical properties, and for corrosion resistance the objective is to achieve maximum homogeneity. Thus the tendency has been to ever lower the carbon and correlatively the chromium carbide content of the austenitic steels. Today stainless steels with carbon less than 0.03 pct are beginning to find their true place, and this is being aided in major degree by our Company's introduction of a new type of ferrochromium having negligible carbon. The role of carbon in these austenitic steels has long been recognized, and a truly enormous amount of research has been devoted to the subject. Much has been learned about corrosion resistance, but the attack on the problem from the point of view of carbide precipitation and the nature thereof has left much to be understood. Because of its fundamental importance to the future of stainless steels, further study of the mechanism of carbide formation in austenitic steels is of interest. In the 18-8 Cr-Ni steels, which are typical of the austenitic class of steel, carbon is soluble in the aus-tenite to the extent of approximately 0.15 pct at 1832°F (1000°C). The solubility becomes less with decreasing temperature, so that at 1652°F (900°C) the solubility limit is approximately 0.06 pct, at 1472°F (800°C) it is about 0.03 pct, and at 932°F (500°C) it is approximately 0.01 pct. Obviously this is the ideal situation for the classical precipitation phenomenon. It is true that, in a sense, 18-8 austenite resulting from annealing is in a metastable state, and the phenomenon of ferritic precipitation from this austenite should be considered. However, in a so-called fully austenitic 18-8 steel this is secondary with respect to the carbides and can be neglected. A wide variety of chromium carbides is known. Only one chromium carbide, Cr,,C,,, frequently referred to as Cr,C, has been found in unmodified low carbon 18-8 steel. This, fortunately, simplifies the study of the precipitation phenomena. For this study an A.I.S.I. type 304 stainless steel of commercial quality was selected. Analysis showed C 0.07 pct, Mn 0.49 pct, Si 0.33 pct, Ni 9.34 pct, Cr 18.91 pct, and N 0.033 pct. As expected with this composition the steel was homogeneous after annealing except for a few pools of ferrite, which were disregarded in that their location was not coincident with subsequent carbide precipitation areas. On corrosion testing the steel was normal and typical of good commercial quality. Specimens 1/2xlx4 in. were annealed and subjected to precipitation heat treatment for 100 hr at 100" temperature intervals from 1000° to 1500°F and for ten selected intervals ranging from 5 min to 64 hr at 1300°F. These blocks were then cut into small pieces for metallographic studies. The first problem

Jan 1, 1953

By E. T. Hayes, A. H. Roberson, M. H. Davies

R. F. Dornagala and D. J. McPherson (Armour Research Foundation, Chicago)—I should like to compliment the authors for a workmanlike job in determining the partial phase diagram of a system comprised of two rnetals which are certainly not easy to work with. We are completing work at Armour Research Foundation on an Atomic Energy Commission-sponsored project for the determination of eight zirconium binary diagrams. Work on the Zr-Cr system has been completed and should be published within the next year. For our work, Westinghouse Grade 3 iodide crystal bar served as the zirconium melting stock. Johnson-Matthey, electrolytic chromium, specially treated for oxygen removal, was employed. The overall constitution of the system determined at Armour Research Foundation is in very good agreement with the present work. We found a eutectic at 18 pct Cr and 1280 °C, somewhat lower than the value reported. This temperature was confirmed by thermal analysis, incipient melting studies, and regular isothermal anneals. The eutectoid was located close to 1 pct Cr and 835°C by metallographic analysis of annealed specimens. Maximum solubility of chromium in /S zirconium was 4.5 pct at the eutectic temperature. Chromium solubility in a zirconium was less than 0.28 pct at all temperatures. We found the compound at 53 pct to melt around 1700°C, with an open maximum, but determined its crystal structure to be hexagonal close-packed (MgZn, type). The lattice parameters were in excellent agreement with those determined by Wallbaum in 1942. The diagrams are in substantial agreement, and .part of the differences are undoubtedly due to the use of different zirconium melting stock. M. K. McQuillan (Birmingham, England)—I read this paper with a great deal of interest, as it covered the same field as some work of my own.' There are a number of points in the present paper on which I would like to comment. First, I should say that I, too, used zirconium prepared by magnesium reduction of the tetrachloride and electrolytically prepared chromium, and melted the alloys in a Kroll-type arc furnace. The purity of my alloys should, therefore, be comparable with the purity of those of the present authors, and any differences in our observations would not be expected to be attributable to this cause. The differences between my observations and theirs concern the presence of the eutectic, the temperature of the eutectoid, and the melting point of the compound. I would be very much interested in any further evidence the authors may have for the occurrence of the eutectic at 1380°C. During the course of my work I noted that a number of my alloys containing 60 to 90 pct Zr melted at about 1400 °C, and for a time assumed that a eutectic occurred at this temperature as described in the paper. On further investigation, however, I found that the structures of the as-melted alloys could not be made to fit in with this interpretation of the system. If a eutectic exists in this region of the system it would be expected that the as-melted alloys would show the usual type of cast structure, i.e., dendrites of the compound plus eutectic. This, however, does not occur, as may be seen from Fig. 9. The compound seen there is not dendritic in form, and the remaining material is by no means certainly eutectic. It may be argued that a compound such as ZrCrl would not form dendrites but would tend to crystallize in geometric shapes. In this case, however, I have evidence to the contrary, as on the chromium side of the compound, where a eutectic occurs at about 1545"C, the compound formed from the liquid takes on a conventional dendritic form, and the eutectic is observed in the interdendritic spaces in the usual way. There is no reason to suppose that the compound would behave differently in an alloy lying on the zirconium side of the compound composition if a eutectic existed there too.

Jan 1, 1953

By Ruddle R. W.

The slags produced in copper smelting are largely composed of silica and ferrous oxide and may therefore be regarded as essentially ferrous silicates. A fair amount of information is available on the constitutions of the liquid slags used in copper smelting and, in this connection, the large volume of work being carried out on steelmaking slags should be helpful. Constitutional diagrams are available for most of the principal systems involved (SiO2-FeO; SiO2-FeO-Al2O 3; SiO2-FeO-CaO; SiO2-FeO- MgO; and SiO2-FeO-CaO-Al2O3) and these show that additions of Al2O3 and CaO reduce the freezing points of SiO2-FeO slags but that additions of MgO increase the freezing point. A certain amount of information is available on the thermodynamics of slags, but much further work on this subject is required. Modern theories of the constitution of liquid slags deny the existence of molecular compounds but consider that liquid slags are mixtures of various ions such as, Fe2+. O2- and SiO4(4-). Little appears to be known of the reactions between matte and minor constituents dissolved in the slag

Jan 1, 1953

By Kenneth Schellinger

THE terms surface tension and surface energy are well known when applied to liquids and are generally described by referring to the excess energy of the air: liquid interface as a result of unsaturated molecular forces surrounding the surface molecules of the liquid due to the presence of the air phase on one side. Such unbalanced forces produce the familiar water droplet of spherical form and are generally summed up as a surface tension measured in dynes per centimeter which can be shown mathematically to be equal numerically to a corresponding surface energy expressed in ergs per square centimeter. A specific surface energy, however, is best thought of as the energy necessary to produce one unit, of new surface on a substance. Hence, in producing a bubble in a flotation cell the impeller must supply surface energy corresponding to the air: liquid interfacial area on the interior of the bubble. Inasmuch as it is relatively easy to extend or contract the surface of a liquid, there are a number of successful methods for liquid surface tension, or energy, measurement based upon surface deformation. This happy state of affairs does not, however, extend to solids, which are considered to possess surface energies for the same reasons as do liquids, i.e. because of unsaturated ionic bonds at the solid: gas interface. As in the case of the flotation cell producing surface on liquids as new bubbles, it takes energy to produce new surface on solids as new particles. As every mill man knows, this surface is produced on mineral solids in a grinding mill by the action of a tumbling mass of iron balls. But here so much energy usually is wasted by the inefficient action of these balls that a large amount of heat is generated, and the surface energy production may be easily confused with the energy necessary to produce this ineffective heat. The tumbling balls and fracturing minerals ultimately take their energy from a rather large electric motor. It has been variously estimated that from 10 to 20 pct'" only of this energy from the motor does not appear as heat and may be presumed to appear as surface energy on the min- erals present. Such a production of new surface on the mineral phases is accompanied, of course, by a size reduction that is inevitable as more and more mineral interior molecules become surface molecules by the fracture exposure. This size reduction of mineral particles, although the most obvious feature and perhaps the sole object of the milling operation, is from this energy viewpoint the outward manifestation of the production of surface energy only. Measurement of the characteristic surface energies of pure minerals and their various mixtures in ores would be a step towards understanding of the energetics of the commercial grinding operation. In addition, the characteristic surface energy of a mineral is probably a physical property specific for that mineral, and therefore, from a scientific standpoint, should be measured. It is interesting to note that, in contrast to the large body of work on the surface tensions of liquid systems and biological systems, the field of solid surface energies has been neglected. Prior to 1920 it is difficult to find more than one or two references to work on solid surface energies in Chemical Abstracts. Since 1920 such references number somewhat less than 100, while those on liquid systems are numbered in the thousands. Much of this apparent neglect of the field of solid surface energies (the term is intended to be somewhat inclusive at this point and refers both to the solid: gas, and the solid:liquid interface) is because of the lack of a reliable method of measurement rather than any lack of scientific curiosity. It was, and still is, difficult to produce new surface on a solid without the simultaneous production of interior changes in the same solid which may consume part of the energy used. The extension in the surface area can be measured, but the interior crystal-

Jan 1, 1953

By John B. Goodman

A LOW-TEMPERATURE carbonization assay test is described, and factual data derived from this test are presented. The test procedure outlined in this report incorporates a mild-steel retort of improved design, an accurately controlled method of heating, and a complete collection and condensation system for the solid, liquid, and gaseous products of carbonization. The test described establishes, under closely controlled conditions, the relationship of temperature to yields of products on carbonization. Noncoking or weakly coking coals and other carbonaceous material are particularly amenable to testing by the assay. Mass balances of 100 percent± 0.3 are obtainable by this test. It is believed that the efficiency of the test and the accuracy of the type data obtained have been materially increased.

Jan 1, 1953

By F. W. Brown

In 1942 the Explosives Division investigated electrostatic hazards associated with the manufacture, storage, and use of explosives. A report was issued in 19454/ presenting the data on the spark sensitivities of explosives. In 1948, the apparatus was redesigned and rebuilt to make the routine testing of explosives safer and more convenient. The rebuilt apparatus is described in this re-issue of the former report. Included are details of construction and a list of parts. PRINCIPLES OF METHOD In normal procedures without special precautions, it is possible for static charges to be accumulated on individuals or on ungrounded equipment or structures.5/ Static charges may be produced in many ways, but they are most commonly produced by rubbing or successive contact and separation of unlike surfaces, at least one of which is usually an insulator.

Jan 1, 1953

By Paul Pietrokowsky

THE formation of intermediate phases in the solid state reaction of titanium with silicon, germanium. and tin (of subgroup 4B in the periodic table) was the subject of a recent paper.' Further investigation of the system Ti-Sn revealed the presence of a new compound on the titanium-rich side of this phase diagram. Metallographic evidence indicated that this new phase was situated very close to 75 atomic pct Ti. The present work is concerned with the crystal structure of the intermediate phase Ti3Sn. Iodide-process titanium metal, furnished by the New Jersey Zinc Co., was used in this investigation. The metallic tin was received in powder form from Charles Hardy Inc., New York; its purity was 99.80 pct. The titanium rod was machined into small cups 1 cm in diam and about 1.5 cm in height. The tin powder was compacted, melted, and then placed in the titanium cups and alloyed by electric arc melting in a helium atmosphere. The alloys, weighing approximately 8 g, were sealed in evacuated quartz tubes and homogenized at 1030°C for 5 days. This isothermal heat treatment was terminated by a water quench from the soaking temperature. Filings of the alloyed pellets were sealed in evacuated quartz bulbs and quenched from 1030°C into liquid argon. A 14.32 cm Debye Scherrer X-ray camera was used for the powder diffraction study. The copper radiation was filtered. X-ray diffraction data for the compound Ti3Sn are given in Table I. The data were indexed on the basis of a hexagonal lattice. Good agreement between observed and calculated values of the square of the reciprocal interplanar spacings was obtained with the following expression: (1/d)2 = 0.03810 (h2 + hk + k2) + 0.04410 (l2) Unit cell parameters were calculated by the method of least squares from the reflections (20.3), (22.2), (40.1), and (42.1); ao = 5.916 & 0.004A, co = 4.764 ± 0.004A, and co/ao = 0.805. The relatively small size of the unit cell allowed the unambiguous indexing of most of the reflections from planes of large spacing. An inspection of the assigned indices (Table I) reveals the absence of (hk.l) reflections when 1 2n. A systematic absence of this type leads to the space group C 6/mmc or one of its subgroups. Assuming, for a first approximation, a linear increase in the density of titanium with the addition of tin, it follows that there are two stoichiometric molecules of Ti3Sn per unit cell. The density calculated from X-ray measurements is 5.194 g cm-'. At this point it became clear that Ti3Sn might be isomorphous with Mg3Cd. The 6 Ti and 2 Sn atoms were placed in the following positions of space group D4 6h, C 6/mmc: 6Tiin (h): X 2X 1/4; 22;; 1/4;Xx 1/4;x2x3/4; 2x x 3/4; x x 4; with x = 516 2 Sn in (c): 1/3 2/3 1/4; 2/3 1/3 3/4.

Jan 1, 1953

By O. D. Sherby, J. E. Dorn

SEVERAL years ago Zener and Hollomon1 suggested that the flow stress of metals might be related to the temperature and strain rate in accord with the functional equation: s=s(eeh/rt) [1] at the same state. The Zener-Hollomon relation also contains the significant tacit implication that the energy for activation, AH, is substantially independent of the state of the material. The utility of this method for correlating creep data with tensile data was illustrated in a preliminary reportL on the effect of alloying additions on the secondary creep rates of binary a solid solutions in aluminum as shown for Al-Mg alloys in Fig. 1. Not only do the secondary creep and ultimate tensile properties for each alloy correlate well on this plot but in addition the activation energy, AH = 17,900 R cal per mol. is identical for the various compositions. Similar types of curves correlating the secondary creep rates at 422°K (300°F) with ultimate tensile data were also obtained for a series of dilute a solid solutions of copper, germanium, zinc, and silver in aluminum. In all cases the activation energy for creep, AH, was found to be equal to about 17,900 R cal per mol independent of the type of alloying element or its concentration. The coincidence of the activation energies for these alloys is probably due to the fact that the activation energies for creep are rather insensitive to small composition changes. Alloying additions, as shown in Fig. 1, however, increased the stress necessary to obtain equivalent values of ee?H/RT. Thus the stress level in curves of the type represented by Fig. 1 gives the relative creep strengths of the various alloys. Inasmuch as these correlations between creep and tensile data were obtained for creep tests at 422°K, it appeared advisable to ascertain the range of secondary creep rates and temperatures over which correlations between creep and tensile data could be made on the basis of the Zener-Hollomon relationship. If, for example, the activation energy changes with different ranges of creep temperatures, the utility of the proposed analysis would be severely weakened. But if AH is constant not only for all dilute alloys, but also over wide ranges of temperature and secondary creep rates, confidence will be developed not only in the broad utility of the Zener- Table I. Chemical Analysis':' and Grain Size of Alloys Mean Grain Residual Impurities. Wt Pct Diam- Alloying Atomic-eter, Element Pct Si Fe Cu Mg Mn mm Aluminum 99.987 0.003 0.003 0.006 0.001 0.25 Magnesium 1.617 0.003 0.004 0.006 0.26 Copper 0.101 0.003 0.003 0.0006 0.001 0.29 Zinc 1.616 0.003 0.005 0.007 0.001 '0.26 * The authors express their appreciation to the Aluminum Company of America for the preparation and chemical analyses of these alloys. Hollomon relationship, but also in its theoretical justification. The following investigation was instituted in order to ascertain the range of validity of the Zener-Hollomon relationship when it is applied to creep and tension data. Materials, Equipment, Technique In view of rather extensive correlatable data now available on the plastic properties of a series of binary a solid solutions of magnesium, copper, germanium, zinc, and silver in aluminum, these alloys were again selected for the present investigation. Previous reports have already covered the tensile properties of these alloys at subatmospheric temperatures," and at elevated temperature," as well as their fatigue properties at atmospheric temperatures, nd their creep properties at 422°K.' Resistivity measurementsa as well as precision lattice constant determinations? evealed that these alloys are a solid solutions. After homogenization. 0.100 in. thick sheets were rolled to 0.070 in. in thickness and recrystallized to about the same grain size. Since the details of these treatments were reported previously," they will not be repeated here. In order to appropriately reduce the scope of creep tests in this investigation only the typical alloys shown in Table I were investigated. All creep specimens were machined such that their tensile axes were in the rolling direction of the 0.070 in. sheet stock. The gage section was 2 in. long and 0.500 in. wide with a reduced section of 3.50 in. Creep strains were measured by means of rack and pinion type extensometers with a sensitivity of 0.005 in. per division. Readings were estimated to 1/10 of

Jan 1, 1953

By J. L. Carne

ORE control is a matter of planning and supervision based on a foreknowledge of the content and distribution of ore. The Inspiration orebody is predominately a copper-sulphide blanket, overlain by an oxidized zone of copper silicates, copper carbonates, and barren capping. Most of the ore is treated by leaching, and the optimum requirement of this method is the goal toward which the mining schedule is aimed. Both open-pit operations and underground mining are used. The problems of ore control at Inspiration are: I—maintenance of metallurgical balance, 2—conservation of oxide ore, and 3—mining out of the orebody at an average grade which parallels that of the reserve figure. Prior to the fall of 1926 all of the Inspiration division ores were treated by flotation, but the mixed ores of the Live Oak—Keystone section carried too large a proportion of copper in the form of chrysocolla for satisfactory flotation. For this type of mixed ore the leaching process now in use had been worked out, and the plant was put into operation in the fall of 1926. The process is known as the ferric sulphate leach, and the leaching solvents contain both ferric sulphate and free sulphuric acid. Sulphide copper in the form of chalcocite is leached by the ferric sulphate, and the oxidized copper minerals are dissolved by the sulphuric acid. From the beginning of operations to the present time the plant has treated some 67 thousand tons of ore having an average copper content of 1.142 pct, of which 0.605 pct has been in the form of oxidized copper minerals. The plant is currently being operated at the rate of 11,500 tons per day, 7 days per week. However, this tonnage is produced in 6 days of mine operation. The average current grade is approximately 1 pct copper, of which about 50 pct is present as oxidized or acid-soluble copper. Close control of metallurgical procedures is a vital factor in operation of the plant and is in turn dependent upon careful regulation of feed. An excess of sulphide copper requires the presence of more ferric sulphate in the leaching solvents. On the other hand, an excess of ferric sulphate in the presence of a low sulphide feed seriously reduces the efficiency of electrolytic precipitation in tank house operations. This condition must be avoided at all costs. An additional factor must be considered. It is known that the sulphide content is predominant in the ore which remains in the reserve. To maintain the necessary sulphide-oxide proportion, so that the entire reserve will mine out at both a grade and a sulphide-oxide ratio that will be permissible throughout the remaining life of the property, it is obvious that the oxide reserve must be currently preserved to as great an extent as possible. Fortunately much of the oxide reserve is found in the open-pit operation. This happy circumstance adds flexibility to the procedure and makes it possible to maintain the close regulation necessary to insure best overall results, both mining and metallurgical. The two ore streams from the pit and underground operations join at the coarse-crushing plant, and proper control must be exercised before the ore reaches this point. The open pit is currently providing about 55 pct of the ore and underground operations the balance of production. Both operations are under a single superintendent so that the closely interrelated problems may be more readily controlled. The least flexible of the two producing units is the underground mine, where the mining method is block caving. Although a block of ground may be undercut and developed, characteristics of the material determine its caving action. The ore in the chutes must be drawn. The area currently mined from underground is in a zone predominately sulphide and is generally

Jan 1, 1953

By O. J. C. Runnalls, L. M. Pidgeon

Some observations on the kinetics of the iodide process are reported. The deposition rate is geometry-sensitive in a system containing a finely divided titanium charge. Further, results indicate that the iodine diffusion rate influences the velocity of the process. The nonvolatile iodide, Til,, forms in the hot filament zone, thus removing iodine from the cycle. TITANIUM metal of 99.9 pct purity may be prepared using a refining technique originated by Van Arkel and de Boer.' The purity of this metal, commonly called iodide titanium, exceeds that produced by any known process. In a recent application, the method was employed by Gonser et al.² to prepare titanium rods up to 2 to 3 cm in diam. In the Van Arkel-de Boer system, the relative influence of the fundamental mechanisms: l—production of titanium iodides, 2—gaseous countercurrent diffusion, and 3—decomposition, on the deposition rate have not been clearly established. Blocher and Campbell" have indicated that the controlling step in the process under practical conditions of operation may be the reaction rate of iodine with the crude metal. Fast' reported that crude titanium metal reacted with iodine rapidly, even at room temperature, in his apparatus. Little has been reported on the effect of gaseous diffusion or decomposition on the deposition rate. It is these aspects of the process about which this investigation is centered. An attempt has been made to separate these latter effects from those due to the formation of the iodides at the crude metal surface by a division of the experimental program. Reaction of Iodine with Titanium Apparatus: In the investigation of gas-metal reactions of this type, the chemical reactivity of the halogen and halide vapors dictates the use of all-glass apparatus. In such a system standard techniques for measuring reaction rates are difficult to employ. Here, a simple apparatus was devised (Fig. 1) so that some indication of the reactivity of titanium powder with iodine vapor could be obtained. A stream of iodine gas was evolved from a bulb of controlled temperature and passed over a sample of titanium powder heated in a horizontal tube furnace. The product of the reaction, TiI4, volatilized and was condensed outside the furnace in a series of four glass bulbs, each cooled to room temperature in turn. Preliminary experiments indicated that distillation was retarded in a sealed evacuated system due to a pressure build-up in the condensing end of the apparatus. Hence, the system was pumped continuously using a mechanical pump and two oil diffusion pumps in series, through a liquid air trap. The iodine bulb was made large and a capillary restriction was inserted between the titanium bulb and the condensers so that the iodine pressure over the metal would approach the equilibrium pressure over solid iodine crystals. The effect of this restriction on the evaporation rate of TiI4, was determined separately. The iodine bulb was heated in an oil bath controlled to ±2°C. The titanium bulb temperature was automatically controlled to ±5°C. Procedure: About 200 mg of —30 mesh titanium powder, weighed to 0.1 mg, was placed in the reaction bulb after part B had been joined to part A. The powder was tapped into a long (5 cm) shallow mass along the bottom of the tube. Two chromel-alumel thermocouples were inserted into the magnesium radiator which was clamped to the reaction

Jan 1, 1953

By Gearge C. Wallick

This paper describes experimental procedures for the calibration of capillary tubes to be employed as comparison standards in gas flow-rate measurements and considers several types of flow which were observed in the calibration of seven capillaries of varying diameter. It is shown that under certain experimental conditions deviations from Poiseuille flow are observed which may not be attributed to turbulence, and that this flow behavior may be described empirically by introducing the classical kinetic energy correction into the Poiseuille equation. INTRODUCTION Techniques have been developed for the measurement of the volume rate of flow of nitrogen through glass capillary tubes as a function both of the differential pressure applied and of the absolute gas pressure. Capillary tubes thus calibrated are frequently used to determine the rate of gas flow through a porous sample in the measurement of slip-corrected permeability. The purpose of this note is to describe the calibration procedure and to discuss some observed deviations from the ideal flow behavior predicted by the Poiseuille equation. EXPERIMENTAL PROCEDURE The volume flow rate of nitrogen as a function of the differential pressure was determined experimentally for a series of seven glass capillary tubes of varying diameter. As is shown in Table 1, the capillary radii in the series ranged from 0.004 cm for K1 to 0.07 cm for K7. The capillary tubes were cut from capillary tubing purchased on special order from several manufacturers and the bore radii were determined by microscopic measurement. The gas volume flow rate was measured for each capillary tube at a series of differential pressures in the range from 0 to 3 cm of mercury and at average absolute pressures of 1.0, 2.5, 4.0, and 6.0 atm. Experimental Procedure for Small Capillaries A schematic diagram of the apparatus used to calibrate the three smallest capillaries, Kl, K2, and K3, is shown in Fig. 1. By means of a standard Ruska Instrument Corp. volumetric pump (equipped with a synchronous motor drive, two stages of gear reduction, and a quick-change lathe gear box), nitrogen was displaced by mercury from a metal cell immersed in a constant-temperature bath. The pump, the line to the cell, and a part of the cell were filled with mercury. As mercury was forced into the cell, it displaced nitrogen which passed through the capillary tube being calibrated and into a large container with a volume of approximately 30 liters. Since the volume of this container was very large compared to the total volume change of the gas resulting from the action of the displacement pump, the absolute pressure of the system was essentially constant throughout any one run. Prior to any determination this pressure could be set at any desired level by means of an auxiliary nitrogen cylinder. The differential pressure across the capillary was measured with a Meriam Red Oil manometer and recorded together with the corresponding pump displacement rate which was equal to the gas flow rate. By repeating this process for a series of different displacement rates at each of the absolute pressures of interest, the data necessary for plotting the calibration curves for capillaries K1, K2, and K3 were obtained. All calibration measurements were made in a constant temperature room to minimize errors due to temperature fluctuations. In each run. the flow was maintained until equilibrium was established. Experimental Procedures for Large Capillaries The flow rates through Capillaries K4, K5, K6, and K7 required to obtain the pressure drops desired were larger than could be obtained from available constant displacement pumps, and it was thus necessary to employ an alternative calibration procedure. The arrangement of apparatus used in calibrating these capillaries at an average pressure of one atmosphere is shown in Fig. 2. Each capillary was calibrated by flowing nitrogen through the capillary and recording the differential pressure as a function of the flow rate. 'The differential pressure was measured with a Meriam Red Oil manometer and the flow rate was determined by collecting the effluent gas over water at constant pressure and recording the increase in volume per unit time after an equilibrium had been established. Appropriate corrections were made for the

Jan 1, 1953