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By Worthen Bradley, R. G. Hall

THIS paper will attempt to show how a metallurgical problem at one California quicksilver mine was solved, and how the solution was applied successfully at another mine. The pronouns "we" and "our," as used below, refer to the Bradley Mining Co. of San Francisco. The term "concurrent firing" for the purpose of this paper can be defined as feeding and firing a rotary kiln at the same end-that is, of course, the upper end. This is as opposed to "counter-current firing," the orthodox method, in which a kiln is fed at the upper and fired at the lower end. The terms "quicksilver" and "mercury" are used interchangeably. EARLY REFERENCES The earliest work on nonferrous metallurgy, we believe, was The Pirotechnia of Vannocio Biringuccio,1 its first edition having been printed in Italy in 1540. Quoting from its chapter entitled "Concerning Quicksilver and Its Ore": Quicksilver . . . is one of the gods and has divine strength in itself, and also, to the annoyance of the alchemists, it is winged. Hence, when it sees that it is in gravest danger, it loosens itself from . . . every bond . . . and flies away into the heavens, escaping from the hands of those who crucify it. Almost laughing, it leaves all its adversaries mocked and scorned, with their phials and filters empty . . . How thorough a job, under certain conditions, it can do of mocking its adversaries and leaving their phials and filters empty, was found out four centuries later at the Sulphur Bank mine, on the east shore of Clear Lake, in Lake County, California. The other mine mentioned in the title is the Reed, in Yolo County, California, 35 miles by road southeast of Sulphur Bank. Reed and Sulphur Bank ranked respectively fifth and seventh in U. S. production in 1943. The earliest direct reference we can find to furnacing troubles at these mines was by Thomas Egleston in 1890.2 Speaking of Sulphur Bank, Egleston says: Sometimes there is more sulphur than cinnabar in the ore, which is a detriment to both . . . making the sulphur impure, and rendering the cinnabar difficult to work on account of the soot. In some of the early . . . furnaces the accumulation of soot from the excess of sulphur has been known to penetrate as far as the fan blower at the end of the . . . condensers, and completely prevent its revolution. In order to get rid of the inconvenience of this accumulation . . . , as well as to get a commercial value from the sulphur, it (the sulphur) is now separated by steam and sold. It is claimed that the sulphur alone pays all the expenses of . . . the mine. The mine was first worked for sulphur, and the cinnabar it contained was considered to be an inconvenience, and was carefully picked out and thrown away. as its richness and value were not

Jan 1, 1945

By Joan Melcher

The oil embargo and increasing disillusionment with nu- clear power have put this country's abundant coal reserves in growing demand. Both the government and industry are looking toward increased coal mining, and with this goes an increased interest in new and advanced methods of coal utilization. One advanced coal system stands out among the rest-magnetohydrodynamics (MHD). Its high efficiency, strong probability of sulfur dioxide control, and limited consumption of cooling water place MHD in a unique position to help the power generation industry. Another point in MHD's favor is the capital costs of operation, which are lower than those of other advanced technologies. However, initial costs are higher and realization of a commercial MHD plant in this country may be more than a decade away.

Jan 12, 1977

By J. W. Sandelin, L. S. Birks

The group five metals, vanadium, niobium, and tantalum all show cold-rolled textures of {100)(011) and {112)(0ll) with a preference for the (100) in vanadium and niobium and for the {112) in tantalum. Recrys-tallization texture of (100) and (111) was reported1 for vanadium after annealing (no temperature stated). For tantal~m ,~ annealing below 1200°C strengthened the (112) texture but the (111) texture increased and was predominant as the annealing temperature was raised to 2500°C. Annealing niobium up to 1100°C strengthened the ( 100) texture and developed a weak (111) texture.' In the present work niobium has been annealed up to 2000°C. Nearly 70 pct of the grains showed {111) texture with only a weak (112) component and an insignificant (100) component remaining. In addition, double-crystal rocking curves were used to follow the increase in crystal perfection of the grains with increased annealing time. Material and Treatment. Samples i by 4 in. were sawed from & -in.-thick cold-rolled niobium sheet obtained from Wah Chang. Chemical analysis of the material showed it to be 99.4 pct pure with tantalum as the major impurity. Individual pieces were annealed for 2, 15, 30, and 60 rnin in a vacuum of 10'* Torr using an rf generator. They were etched until the grain boundaries were well-defined, Fig. 1. Average grain size varied from 1 mm for 2 min annealing to 2 mm for 60 rnin annealing. Experimental Results. Preferred Orientation. The orientations of 97 of the 117 grains in the specimens of Fig. 1 were determined by back-reflect ion Laue patterns. A General Electric 10-cm-diam cylindrical camera was used rather than the conventional flat camera in order to record more of the low-index spots. The method proposed by Forest, Barton, and schieltz4 was used to transform the cylindrical film patterns to standard stereographic projections. Table I gives the compilation of data. Even 2 rnin anneal at 2000°C is sufficient to yield a strong (111) preferred orientation, and the percentage of grains with this orientation increases steadily with annealing time at the expense of all other orientations. Crystal Perfection. X-ray topographs were taken of each specimen in both the (111) and (112) orientation using the method described by Birks and Grant.' As the anneal time increases, the grains become larger and the individual reflections become slightly more uniform in intensity, indicating an increase in crystal perfection. For a more quantitative measure of crystal perfection, it was necessary to measure the double-crystal rocking curve. The spectrometer employed was a Gaertner instrument of Compton design. LiF was chosen for the first crystal because the (400) reflection with d spacing of 1.05 AU is a good match to the (222) niobium reflection with d spacing of 0.95 AU. CuKp radiation was used in order to further reduce the d spacing mixmatch correction.' A variable aperture was placed between the LiF and the niobium specimen so that a single grain or even a small portion of a grain could be examined. Fig. 2 shows typical rocking curves for the four annealing times. For the 2-min specimen, a single peak is observed with 10' of arc full-breadth at half maximum. As the annealing time is increased to 15 or 30 min, several sharper peaks of 40 to 80" breadth can be seen within a single grain. After 60 rnin anneal only a single peak of about 30" is observed. Table I1 shows the corrected rocking curve breadths and the dislocation densities, ND. The latter were calculated from the equation7 where W is the corrected rocking curve breadth at half maximum in radians and b is the effective Burger's vector. For (110)(111) slip in niobium, b is 2.86 AU. Discussion. The annealing of cold-rolled niobium at 2000°C causes rapid preferential growth of grains with {ill} orientation. After only 2 rnin annealing time, 35 pct of the grains have the (111) orientation, and after

Jan 1, 1968

By Leroy Palmer

ALL the domestic. production of magnesite during 1925 came from two states, California and Washington. Of a total of 120,660 tons of crude ore, 64,600 tons, or 54 per cent., were produced in California.1 Of .this quantity California produced about 99 per cent. of the caustic calcined, but only 10 per cent. of the dead-burned. The largest producer was C. S. Maltby, of San Francisco, who operated the Red Mountain mine, in Santa Clara County, and the Sampson mine, in San Benito County, under lease. These two mines have been studied by the author, and offer interesting comparisons as to mining and treatment methods and final products. GEOLOGY The general geology of the magnesite deposits of California has been described by Hess,2 Bain3 and others,4 and although a detailed discussion is not necessary here, a brief summary will assist in understanding mining conditions. California magnesite, when comparatively pure, is usually a white, fine-grained rock, with a conchoidal fracture, occurring in veins and lense-like masses in serpentine. The veins vary considerably in width, and usually occur in a series of more or less parallel veins intersected by other series or systems of veins, probably following original or secondary fissures in the enclosing serpentine. The most generally accepted theory of origin is that the magnesite was formed by the action of surface waters charged with C02 percolating downward through fissures and changing the magnesium silicates of the serpentine into magnesium carbonate.

Jan 1, 1927

By W. F. Holbrook, C. E. Wood, E. P. Barrett

THE high-frequency laboratory induction furnace with a rotating liquid crucible enables research workers to conduct certain investigations heretofore very difficult or impossible to realize because vessels are not obtainable that are capable of resisting the physical conditions or the chemical actions to which they are subjected. Applications for patents covering commercial uses of centrifugal liquid crucibles were filed in the United States in 1919,1 in France in 1925, in the United States and Germany in 1926,2 and in France in 1927.3 In 1928, Schuette and Maier,4 of the Bureau of Mines, reported the construction of a whirling table beneath a high-frequency induction furnace. SHAPE AND SIZE OF CENTRIFUGAL LIQUID CRUCIBLES When a vessel containing a liquid is rotated, the inner surface of the liquid takes the shape of a paraboloid under the simultaneous action of centrifugal force and gravity. The internal dimensions of the paraboloid rotating liquid crucible are governed by the diameter of the container and .its speed of rotation. Melted Wood's metal was poured into cylinders 2 1/2 in. in diameter, which were rotated at 180, 300, and 468 r.p.m. When the metal was solid, a slurry of plaster of Paris was added, and rotation continued until the plaster had set. Fig. 1, a photograph of sections of the cylinders, shows the effect of speed of rotation of the containers upon the shape of the inner surface of the rotating liquid crucibles. TYPES OF FURNACES Three types of high-frequency induction laboratory furnaces using liquid-metal crucibles were designed and constructed by the Blast

Jan 1, 1938

By L. D. Muller, C. P. Sayles

When minerals are mined in arid or semiarid areas where water is at a premium, dry processing is a natural route to take for concentrating or classifying the values. Until recently though, dry processing technique were limited by the lack of suitable equipment. With the advent of the pneumatic pinched sluice at Warren Spring Laboratory, Stevenage, Hertfordshire, England, a new tool emerged to fill this gap and it has the potential of providing industry with a high output concentrator or preconcentrator for dry natural ores and secondary materials. The pneumatic pinched sluice gives every indication of fulfilling these requirements with the added advantage that with homogeneous materials-such as crushed limestone or quartzose sands-it may alternatively operate as a high throughput dry classifier or sizing device. An industrial version of the equipment is now being manufactured by Dryflow Separators Ltd., as sole licensee for the National Re- search Development Corporation.

Jan 1, 1971

By G. B. Sazuyer

DEVELOPMENTS respecting beryllium during the past year have been sufficient to center attention on it as likely to be the most important of any of the chemical elements that have recently found a place for themselves in technical industry. This importance is only potential, however, largely because adequate supplies of beryllium ore will be necessary. The beryllium industry will be only as great as the mines which support it. To find and develop large mines will be the problem. Chief of the immediate commercial developments in the United States is beryllium-copper and its espousal by Anaconda and Riverside even at present high prices. According to the pamphlets of these companies, it ap¬pears that beryllium is to copper nearly what carbon is to iron. When one considers that the tensile strength of pure copper is about 33,000 lb. per sq. in., but that the addition of 1.5 to 2.5 per cent of beryllium produces a heat-treatable alloy with a maximum tensile strength of 220,000 lb. or over, the analogy to carbon and iron is made strikingly, clear. Striking among the properties of beryllium-copper is its resistance to fatigue, claimed to be equal or superior to that of spring steel. It needs little imagination to foresee a great industry for this alloy alone.

Jan 1, 1934

By O. A. E. Jackson

Pebble milling has been practiced in the reduction works of South Africa gold mines for well over 50 years. Originally flint pebbles were imported from Denmark to grind stamp-mill amalgamation- process tailing, which contained a good deal of extractable gold, but local operators soon found that large pieces of ore could be used for the same purpose. The ore is a hard, tough conglomerate in which quartz pebbles are cemented together by a matrix of redeposited silica interspersed with pyrite crystals. The gold, rarely visible, occurs as fine particles mostly segregated at the interface of the pebble and matrix, although a small fraction occurs within the pyrite crystals. There is seldom any gold in the pebbles themselves.

Jan 11, 1959

Alabama.1 Arizona 1 Arkansas 2 California 2 Colorado 7 Connecticut 8 Delaware 9 District of Columbia 9 Florida 10 Georgia 11 Idaho 11 Illinois 11 Indiana 13 Iowa 14 Kansas 14 Kentucky 14 Louisiana 15 Maine 16 Maryland 16

Jan 1, 1952

By P. R. Swann, J. G. Parr

Quenched structures were studied in alloys containing up to 12.5 pct cobalt. The subsequent decomposition of a 10 pct cobalt retained-ß phase alloy was investigated using metallographic and X-ray diffraction methods. Hardness measurements also were made during the decomposition process. Precipitation of Ti2Co is by nucleation and growth; and an activation energy of 50,000 cal per mole was determined. The values of the coefficient ß suggest that the precipitate is pearlitic at temperatures between 450 and 475°C, and spheroidal between 500 and 525°C. THIS paper describes part of a series of invesligations into phase transformations in binary alloys of titanium with transition elements. The general approach is similar to that taken in work on titanium-iron and titanium-nickel alloys.' Previous investigators'' have established the titanium-rich end of the titanium-cobalt phase diagram, reproduced in Fig. 1. Orrell and Fontana' showed that alloys containing more than about 6 pct" cobalt quenched from the ß range, produced 100 pcl retained-p phase. The isothermal decomposition of alloys containing between 0.8 pct Co and 15.5 pct CO was investigated by the same workers in the temperature range 650 to 1000°C. They reported that these alloys transformed into a or Ti,Co depending on the cobalt content, but no quantitative data were given. In the work to be described a series of alloys containing 0.8 pct Co to 12.5 pct Co was examined in the quenched condition. The 10 pct Co alloy (the lowest cobalt content to retain 100 pct ß on quenching) was selected for further work on the tempering kinetics of the ß decomposition. Experimental Procedure Since our own melting equipment was not installed at the outset of this work, the Physical Metallurgy Division of the Department of Mines and Technical Surveys (Ottawa, Canada) prepared the alloys. These were made of Japanese sponge, (which when melted had a value of 103 DPH, using a 1-kg load), and electrolytically prepared cobalt. The al- loys, made up to contain 0.8, 1.6, 3.3, 5.8, 8.3, 10.0 and 12.5 pct Co, were homogenized by swaging into rods at 900°C. Filings were taken from the rods, and any iron chips from the file were separated magnetically. Size fractions of both plus and minus 200 mesh (about 75p) were shown by their constitution, after annealing just below the eutectoid temperature, to contain the same cobalt content. Consequently, it was permissible to use the —200-mesh fraction, knowing it to be representative of the rod composition. Quenching in argon was carried out in a newly designed furnace, whose features include (1) an Inconel furnace tube, (2) a positive pressure of argon maintained at all times in the furnace—even when a sample is removed or inserted. The furnace is shown in Fig. 2 and is described in the Appendix. The tempering processes were carried out on powder samples sealed in evacuated quartz capsules. Since the highest tempering temperature was 525OC, no protection against reaction with the quartz was necessary. (Tests were made on filings of iodide titanium and showed no hardness increase after equivalent heat-treatments.) A thermocouple was attached to the capsule, which was heated to the

Jan 1, 1959

By Edward P. Chapman

IN the Leadville district toward the close of the "intermediate mesothermal period" of mineralization, there occurred a stage of ore deposition marked by a rather complex mineral association. As bismuth minerals formed in many places during this period, it is here called the "bismuth stage" for convenience of description. The minerals so far identified with this stage, listed roughly in the order of prominence, are: chalcopyrite; several varieties of galena, differing slightly from one another in their small contents of silver, bismuth and tellurium; altaite; hessite; galenobismutite; alaskaite; aikinite; ,gold; tennantite; argentite; and perhaps sphalerite and arsenopyrite. With the exception of gold, the age relations of these minerals are difficult to determine. As shown in their descriptions, they all appear contemporaneous and hypogene. Gold may be in part contemporaneous, but most of it is distinctly later. Where minerals of this stage occur so that they can be mined alone, as at the Tucson mine, they constitute high-grade ore. Elsewhere their presence in small amounts has served to increase greatly the value of what otherwise would be low- grade pyritic or zinc-lead sulphide ore. The distribution of the bismuth ores corresponds closely to the distribution of gold ores, though not so general. It seems probable that most of the gold in the district was deposited during the "bismuth stage." These ores occur relatively near the supposed centers of mineralization in Breece and Printer Boy Hills or deep down along the Tucson-Maid fault, which is one of the well recognized channels of mineralization in the Iron Hill and Graham Park areas. Consideration of the high-grade nature of this mineralization and the fact that it appears to be found relatively close to the source of mineralization suggests that prospecting along some of the known channels, even deeper than they have yet been prospected, may offer hope of commercial success.

Jan 1, 1939

By S. W. Parr

FRom a study of sulfur with reference to its specific combination in coal, published as University of Illinois Bulletin No. 111, 1919, it is now possible to determine the various forms of this constituent with a good degree of accuracy. This fact suggests two questions: (1) Are the same analytic methods applicable to coke? (2) Is there any correlation between the forms of sulfur as it occurs in coal and the residual sulfur found in the finished coke? The answer to the second question might be helpful in answering a still further question as to what chemical route the sulfur travels during the carbonization process. While the special studies along these several lines are by no means complete, a few preliminary statements are herewith presented. They may, at least, prove suggestive of further possibilities from a continuation of research along these lines. There is no reason, chemically, why the analytic methods devised for coal should not apply to coke and a fair amount of experience in connection with such use affords confirmation of this statement. The procedure in the case of coal may be briefly outlined as follows: Combinations of sulfur as sulfate, or sulfides other than FeS2, are readily dissolved without disturbing either the pyrite sulfur or the sulfur that is in organic combination by means of dilute hydrochloric acid— 1 part of concentrated HC1 to 10 parts of water or approximately 3 per cent. acid. Digestion at 60" C. for 24 hr. insures the complete removal of the sulfur thus combined. In freshly mined coal the amount of such sulfur is very small; weathering processes, however, may very materially increase the amount of sulfate present. Sulfur in the form of iron pyrites, or marcasite, may be quantitatively removed without oxidation of the organic sulfur as follows: A dilute solution of nitric: acid is prepared having 1 part of concentrated HNO3 to 3 parts of water or with an approximate specific gravity of 1.12. The coal sample, ground to 100 mesh, is digested with this solution at room temperature for 3 or 4 days, filtered and evaporated to dryness, taken up with water, and acidified with hydrochloric acid. It is now ready for precipitation with barium chloride in the usual manner. If sulfate is present in the original sample to an appreciable amount, it should be removed by the procedure outlined above. It is not necessary here to give the methods for determining the two

Jan 1, 1920

MINING, to be precise, ends when the ore is delivered to a bin outside the mine. Usually the next step is concentrating; or, as it is more often called, milling. A few elementary definitions will help make clear the discussion that is to follow. A rock is an aggregate of minerals; copper ore is rock that contains copper-bearing minerals in quantity sufficient to make it profitable to mine and recover the copper in the form of marketable metal. Manifestly, under a literal interpretation, a mass of material might be copper ore one day and merely copper-bearing waste rock a week later, if the price of copper happened to drop in the interim. Emphasis already has been placed on the expansion that took place in the ore reserves of the Porphyry companies as a consequence of the great strides made in the technique of mining and ore treatment. So, even if one inserted a qualifying phrase, "at an average price for the metal," after the word "profitable," the definition would still be open to criticism. Place is another factor. It is evident that a body of excellent ore in Arizona might cease to be ore in the economic sense if it were moved intact to the interior of China. However, it is with ore in its technical and scientific aspect that this chapter is concerned. Speaking in general terms, the ton of Porphyry ore as it arrives at the surface contains 25 to 70 lb. of copper minerals in the form of disseminated particles or thin coats along fracture planes. When subjected to appropriate treatment this ton yields 12 to 40 lb. of metallic copper. These ranges take into account conditions of today and of 25 years ago. Two procedures are available: (1) concentration, followed by smelting of the concentrate, or (2) leaching and precipitation, usually by electrolytic deposition. Smelting and leaching are metallurgic processes in that they involve chemical change; concentration

Jan 1, 1933

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Jan 1, 1938

By C. B. Smith, A. G. Guy

The power and convenience of tensor analysis are employed in deriving the equations that describe three-dimensional diffusion in an n-component system plus vacancies. A "Kirkendall coordinate system, '' defined in principle by Kirkendall markers, is used in defining the intrinsic diffusion coefficients that are of primary interest. The defining equations are then transformed to local cartesian coordinates and to fixed cartesian coordinates, the latter being convenient for experimental measurements. Finally, it is shown how the intrinsic diffusion coefficients can be calculated from the experimentally determined quantities. It is generally recognized that any treatment of the essential diffusion phenomena in metallic systems—the jumping of atoms from one lattice position to another—must be based on movement of the atoms past Kirkendall interfaces.' A logical extension of this idea is the proposal that, fundamentally, diffusion must be described mathematically in terms of "Kirkendall coordinates." The basic equations thus obtained may then be transformed into other coordinate systems, when such transformation leads to simplification of either the experimental or mathematical treatment of diffusion data. Tensor analysis is clearly the appropriate mathematical tool for this purpose, since it provides methods both for determining general equations that are valid for all coordinate systems and for conveniently transforming the equations from one coordinate system to another system related to the first in some known fashion. For the present purpose three coordinate systems are used, and it is convenient to begin with a description of the relations among these three systems. FICK LAW FOR KIRKENDALL COORDINATES The reference coordinate system, and the one that is useful for most experimental measurements, is a cartesian coordinate system, xi (i = 1, 2, 3), fixed with respect to some point in the specimen, such as an end of the alloy bar undergoing diffusion. A second set of coordinates, the Kirkendall coordinate system, is one that in principle can be described by the location of inert markers (Kirkendall interfaces). A convenient mathematical relation between Kirkendall coordinates, x'i, and the reference cartesian coordinates, ii, is obtained by specifying that the Kirkendall coordinate system coincide with the cartesian system at time, t = 0. After diffusion has occurred for some time, t = t, the Kirkendall coordinate system will differ from the reference system in the manner shown schematically for the one-dimensional case in Fig. 1. The third coordinate system is Darken's1 local cartesian-coordinate system, xi, which is identical with ii in orientation and units, but which moves with the point under consideration in the Kirkendall coordinate system. Even though most diffusion problems are essentially one-dimensional, there is an advantage in first carrying out the analysis of the three-dimensional problem to gain a clearer insight into the assumptions that are made in the usual one-dimen-

Jan 1, 1962

By Robert Franke

In view of the prominence which the conical mill has attained in the fine-crushing field within the few years since its introduction, the following comparison with its more mature forerunner, the Chilean mill, based on extensive tests, is submitted in the interest of the milling profession. Soon after designing the concentrating plant of the Miami Copper Co. in 1909, the Hardinge conical mill made its appearance in the milling forum. Its possibility as a suitable crushing device for the plant was well recognized, but in view of the lack of commercial demonstration, at the time, as to capacity, efficiency for desired product, and the still more uncertain factors of cost of maintenance and power consumption, it was deemed that the immediate adoption of this machine throughout the plant would be a hazardous undertaking. For these reasons it was decided to equip the majority of the immediately required units of the plant with Chilean mills, the fine-crushing proficiencies of which were better known, and one section with Hardinge mills, to serve as a test unit for the guidance of future installations and replacements. Thereby, after 1.5 years' operation with both types of mills, a thorough test as to metallurgical efficiency and cost economy has been obtained. The conical mill used in these tests is the 8-ft. Hardinge pebble mill, having a cylinder 22 in. in length. The cylindrical portion of this mill is lined with cast-iron liner plates, and the conical extensions with silex bricks bound together by cement. Each liner plate carries a projecting lifter, the function of which is to increase the height of drop of the lifted material. Danish No. 5 pebbles, obtained from the coast deposits of Denmark, are used for the grinding charge. The Chilean mill used is a fast-running, 3-roller, 6-ft. Saturn mill, with screens of 0.037-in. opening. The feed to these mills is the oversize of Callow screens having 0.029-in. openings, which follow rolls crushing to 0.5 in. For the ore of this mine, a moderately hard but very fissile schist,

Jan 1, 1914

By R. I. Jaffee, F. C. Holden, H. R. Ogden

The effects of grain size and shape on alloys of titanium with nitrogen and aluminum have been determined. Increasing a grain size decreases strength and hardness and increases impact resistance. Quenching from the ß field produces subgrain markings delineating a plates in Ti-N alloys but not in Ti-AI alloys. This suggests a precipitation from the high nitrogen alloys. ALPHA titanium alloys are single-phase alloys with the hexagonal-close-packed structure of a titanium. If these alloys are worked and annealed within the a field, equiaxed structures result in which strength is derived from the solid solution of the alloying elements present. Strain hardening can be used to increase further the strength of a titanium alloys. This is the only other mode of strengthening the a type of alloy. Quenching from the ß field has been noted by many investigators to have little effect on the strength of iodide titanium and on commercial titanium. Ti-A1 alloys were found to be little different in hardness, whether annealed in the a field or quenched from the ß field.' These facts illustrate a characteristic of a titanium alloys: they are insensitive to heat treatments from the ß field. Underlying this heat-treatment insensitivity are the facts that the a-ß field is generally narrow in a titanium alloys, the transformation-temperature range increases with a-stabilizing content, and the a solubilities of the alloying elements are greater than the ß solubilities. When quenching is done from the ß field, there is no supersaturation of the alloying elements in the acicular transformation structure produced. Welds in a titanium alloys generally are ductile, because no transformation hardening occurs during cooling.1,2 Other desirable features of a alloys are: no thermal-stability problem, excellent toughness, and retention of strength at elevated temperatures better than a-ß or ß alloys of comparable room-temperature strength. The prime factors governing the properties of a titanium alloys are the amount and kind of solute present. This can change the a phase from a soft, tough material into a hard, brittle material with no apparent change in microstructure. Moreover, brit-tleness can exist over a wider alloy-content range, without change of phase, than in most other metals. The solutes for a titanium may be divided into interstitial and substitutional types. Oxygen and nitrogen dissolve interstitially in rather large amounts, extending well through the brittle range, and the transformation-temverature ranges are raised in the process.:' , carbon has a maximum interstitial solubility of about 0.5 pct at the peritectoid temperature, while at lower temperatures the solubility decreases to about 0.2 pct.3,5 Substitutional a solutes include aluminum and tin. Aluminum has a high a solubility of 25 pct Al, and increases the transformation-temperature range markedly.6,7 Tin has a high a solubility of about 20 pct, but has a relatively innocuous effect on the transformation-temperature range.' The choice between interstitial and substitutional solutes generally has been conceded to the substitutional solutes because of a belief that they do not have as adverse an effect on ductility and notch toughness. However, a recent investigation8 on the effect of hydrogen on titanium has shown that this element, which is not under compositional control, has a powerful detrimental effect on notch toughness. Hydrogen was shown to form a hydride which is practically insoluble (about 0.002 pct) in a titanium at room temperature, although the solubility at the eutectoid temperature of about 300°C is relatively high, about 0.16 pct. Limited data were presented on the effect of hydrogen on a alloys, where the same impairment of toughness as in unalloyed titanium is found. The work reported here describes the effects of interstitial and substitutional solutes on 1—the mechanical properties of high purity titanium free of titanium hydride and 2—the influence of structural variables on these properties. Nitrogen was selected as an example of an interstitial solute with high solubility and aluminum as a substitutional solute with high solubility. All compositions were well within the ductile range, since it was not intended to study the brittleness problem here, but to study only the factors influencing optimum mechanical properties. Procedures The alloys were prepared from iodide titanium as 1/2 Ib ingots double melted to insure homogeneity.

Jan 1, 1955

By Albert L. Toenges

C. P. HEINER*—I would like to ask Mr. Toenges about the highest rank coal. I did not get that clearly. What kind of coal is that? A. L. TOENGES (author's reply)— The coal in the Matanuska field ranges from high volatile "B" bituminus to anthracite. It all depends on which direction you go in the Matanuska field. C. P. HEINER—Is it a large reserve. A. L. TOENGES—That is what we hope. That is what we are trying to find out. B. W. DYER*—In those strip beds, I wonder how far back the coal would weather ? A. L. TOENGES—I never noticed particularly. B. W. DYER—The weathering does not extend back like it does in this country ? A. L. TOENGES—No, it does not. B. W. DYER—Is that due to the freezing ? A. L. TOENGES—Probably so. B. W. DYER—In this country, you would expect nothing but weathered coal. R. H. SWALLOW*—Along that line, you mentioned some of the seams were on fire. Did you ever know how far back they burned, or was it hard to tell ? A. L. TOENGES—The fires occurred in the mine. That one you refer to was from an inside fire.

Jan 1, 1950

Jan 1, 1893

By Paul A. Beck

While the recrystallization properties of most of the practically important metals are known in considerable detail, those of lead are still relatively little known in spite of some valuable contributions in recent years. This condition probably is due to the difficulties involved in applying the usual methods of investigation. The microscopic method of discriminating between the elongated deformed grains of the familiar lenticular shape and the equiaxed recrys-tallized grains is not successful with fully refined lead: lenticular grains cannot be seen under the microscope with any amount of deformation whatever. The probable cause of this phenomenon was recognized long ago. With large deformation the time of recrystallization at room temperaturc is shorter than the period of preparation of the specimen for microscopic examination; with small deformation the deformed grains arc not noticeably elongated in the first place. However, with small cleformation the migration of the grain boundaries can be observed. The only systematic investigations yet published on the recrystallization of lead, those by R. S. Russell, 1-3 make use of the conditions just described. Russell considered recrystallization completed when no further migration of boundaries could be observed. A serious objection to this method arises from the fact that there is no evidence to support the view that grain-boundary migration results only from recrystallization. If such migration does result from other sources after recrystallization is completed—after the deformed grains have been replaced by new unde-formed grains—the "time of recrystallization" as determined by Russell may be too long. Furthermore, the method is subject to the above.-mentioned limitation because of the unavoidable period of preparation of the sample. According to Russell, even with the fastest technique 5 min. clapsed before the deformed samples were ready for examination, and consequently no reearystallization time shorter than 5 min. could be measured. The lack of success in detecting the recrystallization of lead by the usual hardness or tensile tests is again caused by the time necessary for

Jan 1, 1940