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By E. A. Gulbransen, J. W. Hickman

One of the important factors that determine the resistance of a metal or alloy to further chemical reaction is the structure of the superficial oxide film. A thorough understanding of the physical and chemical structure as well as the stability of the oxide film formed on the surface as a function of time and temperature of the chemical reaction might furnish clues as to the nature of the reaction process and the protective nature of the film. A comprehensive program has been undertaken to study these phenomena. This paper summarizes the structure of the oxide films formed on the metals iron, cobalt, nickel, chromium and copper at temperatures up to 700°C. Before the introduction of the electron diffraction technique, it was necessary to use either direct chemical analyses or X-rav diffraction analyses to determine the nature of the oxide film formed on the metal or alloy. Chemical analyses yields information on the percentages of the several atomic species present in the film while X-ray diffraction analyses yield information on the atomic geometry. In special cases the information obtained may be identical, but in general both viewpoints are necessary. Much of the early work was carried out on the oxidation of bulk samples where thick films were obtained. The products were identified after cooling to room temperature by X-ray diffraction and chemical analyses. Although much useful information has been obtained in this manner. little could be learned about the character of the protective oxides during the period when the films were actually protective. Evidence concerning the chemical structure of thin oxide films has been made possible by the development of the electron diffraction reflection technique. In this method the most fruitful investigations have been made by carrying out the reaction in situ at the temperature at which the film is actually protective. Literature The oxidation of iron has been extensively investigated by X-ray and electron diffraction. Jackson and Quarrelll found that oxide films formed and examined at the same temperature differed considerably from those allowed to cool to room temperature. The results showed that below 400°C the oxide that was stable in intimate contact with iron was Fe³O4; between 515° and 900°C. the stable film was FeO. Above the upper change point of iron the oxide was found to be Fe³O4. From 400' to 515°C., FeO, Fe³O4 or a mixture of the two oxides was found. Recrystallization of the air-formed film below 400' and above 900°C. led to the formation of Fe3O4. In the range where thicker films consisted of FeO, the air-formed film was converted to a new hexagonal oxide not previously described.

Jan 1, 1947

By Samuel Dolbear

PUBLIC discussions of mine finance in the tech-nical press have been confined mainly to methods of providing funds for the development of pros-pects or other mining operations which have not reached the stage of productivity. The application of modern financing methods to mines which have behind them a successful record of net earnings has, for some reason, been given scant consideration by mine owners and managers. In a few conspicuous cases, such for example as the Anaconda Copper Mining Co., Chile Copper Co., and one or two others, industrial finance has been applied to mining operations on the scale and after the fashion of other operations. When extensions are needed re-course is usually had, however, to the sale of common stock, with the obvious disadvantage of diluting the holdings of every stockholder of record prior to such financing. In some cases, it has been sought to over-come this disadvantage by issuing stock purchase rights to shareholders of record. If the stockholder is in a position to acquire additional stock, he may then pre-serve his interest intact, otherwise he must suffer a dilution of his holding. If he purchases additional stock he is, from one point of view, paying more for his in-terest than he bargained for when he made his original purchase. In many cases development and equipment are paid for out of surplus or current earnings. It is sometimes most difficult to explain to a manager why he can afford to borrow money when funds are available from a sur-plus account. Nevertheless, industrial enterprises with adequate surplus accounts often finance new construc-tion by the issuance of bonds. Such a procedure enables the company to maintain its surplus intact, and to con-tinue the payment of dividends during a temporary period of unusual expenditures.

Jan 2, 1927

By Albert Sauveur

Iron, like other metals, solidifies through the formation of dendritic crystals; iron alloys forming solid solutions, like other solid solutions, solidify likewise through the formation of dendritic crystals. The alloying elements or impurities as well as the inclusions segregate generally in the interstices, or "fillings," between the axes and branches of the dendrites; that is, in the portions last to solidify. This results in dendritic segregation or heterogeneity, which is generally persistent and makes possible the revelation of the dendritic crystallization of the metal through the selective action of a suitable etching reagent.' For this purpose, a cuprie solution, such as Le Chatelier's, is generally used, copper being deposited on the pure, or relatively pure, ferrite present in the axes while the fillings remain free, or relatively free, from copper deposition. The dendritic structure, formed on solidification in a steel containing 0.50 per cent. carbon, 0.37 per cent. manganese, 0.12 per cent. silicon, 0.07 per cent. sulfur, and 0.035 per cent. phosphorus is shown, after treatment with Le Chatelier reagent, in Fig. 1 under a magnification of 8 diameters. Commercial steel always contains inclusions of manganese sulfide, which are located in the fillings of the dendrites. Comstock has shown that boiling sodium picrate imparts a dark coloration to these inclusions. We find that this reagent likewise reveals dendritic segregations in commercial steel, as shown in Fig. 2, under a magnification of 8 diameters. which represents the same spot as that shown in Fig. 1. The fillings have been darkened while the axes remain white, the action being, therefore, the reverse of that of cupric reagents. On closer examination, under higher magnification (Fig. 3) it is found that the picrate blackens the small particles of manganese sulfide, that these are frequently surrounded by a rim of white, or relatively white, ferrite, and that both the ferrite

Jan 1, 1924

Despite the uncertain political situation in Katanga, copper and cobalt mining and metallurgical operations of Union Miniere du Haut-Katanga were normal at the time of this writing. In fact operations continued normal after Congo independence on June 30, 1960, with copper and zinc production for that year being slightly higher than in 1959. United Nations military operations from September to December 1961 resulted in death, shutdowns and damage to company persons and installations. Nevertheless, results for that year were only slightly off normal production. Moise Tshombe delared Katanga a separate state after Congo independence. Although there has been tribal unrest, the new State has enjoyed relative calm and normal industry by comparison with other parts of the Congo as a result of the firm hand of Moise Tshombe's government and the continued presence of Belgian officials and technicians.

Jan 12, 1962

By Thomas Brownfield

The chronicle of the oil industry in Oklahoma in 1939 is one of declining production bolstered by strenuous efforts to find new pools or new producing horizons in the older, highly exploited, relatively shallow areas. Production, which averaged 608,000 bbl. daily in 1937, the post-depression peak, declined to 463,000 bbl. daily in 1938 and continued downward to 421,000 bbl. daily for the year 1939. While the state could produce somewhat more oil if demand warranted it, production in most areas is at as great a rate as could be justified on the basis of maximum efficient operation. Outlet for Oklahoma crude has been seriously affected by the increase in production in the Illinois Basin. Crude movements from the Kansas-Oklahoma area to the northeastern consuming centers averaged 314,000 bbl. daily in 1939 as compared with 397,000 bbl. in 1938. Oklahoma producers bore the brunt of this loss of market. The general production decline was accentuated by the August, shutdown of 15 days, precipitated by the action of a major crude purchaser posting a 20-cent reduction in the price of crude. The Oklahoma Corporation Commission, in collaboration with other members of the Interstate Oil Compact Commission, ordered a complete shutdown of all producing wells in order to prevent the premature abandonment of stripper wells, which might result from a prolonged period of production at prices below operating costs. The reduction in price was forestalled, most major purchasers failing to meet the cut in view of the shutdown, and the company initiating the move rescinded its action. Fear of the shutting in of oil wells, especially those making considerable quantities of water, is generally unfounded in the light of a superficial examination of the records. Oklahoma's unprorated pools, which produced 154,000 bbl. daily in May, declined to 152,000 bbl. in June and 143,000 bbl. in July. Immediately following the shutdown, the same pools produced 150,000 bbl. in September, 145,000 in October, and 145,-000 in November. Thus, while the half month's production loss in August has not been made up, the wells apparently hare produced at a greater rate since the shutdown than immediately preceding it.

Jan 1, 1940

By Thomas Brownfield

The chronicle of the oil industry in Oklahoma in 1939 is one of declining production bolstered by strenuous efforts to find new pools or new producing horizons in the older, highly exploited, relatively shallow areas. Production, which averaged 608,000 bbl. daily in 1937, the post-depression peak, declined to 463,000 bbl. daily in 1938 and continued downward to 421,000 bbl. daily for the year 1939. While the state could produce somewhat more oil if demand warranted it, production in most areas is at as great a rate as could be justified on the basis of maximum efficient operation. Outlet for Oklahoma crude has been seriously affected by the increase in production in the Illinois Basin. Crude movements from the Kansas-Oklahoma area to the northeastern consuming centers averaged 314,000 bbl. daily in 1939 as compared with 397,000 bbl. in 1938. Oklahoma producers bore the brunt of this loss of market. The general production decline was accentuated by the August, shutdown of 15 days, precipitated by the action of a major crude purchaser posting a 20-cent reduction in the price of crude. The Oklahoma Corporation Commission, in collaboration with other members of the Interstate Oil Compact Commission, ordered a complete shutdown of all producing wells in order to prevent the premature abandonment of stripper wells, which might result from a prolonged period of production at prices below operating costs. The reduction in price was forestalled, most major purchasers failing to meet the cut in view of the shutdown, and the company initiating the move rescinded its action. Fear of the shutting in of oil wells, especially those making considerable quantities of water, is generally unfounded in the light of a superficial examination of the records. Oklahoma's unprorated pools, which produced 154,000 bbl. daily in May, declined to 152,000 bbl. in June and 143,000 bbl. in July. Immediately following the shutdown, the same pools produced 150,000 bbl. in September, 145,000 in October, and 145,-000 in November. Thus, while the half month's production loss in August has not been made up, the wells apparently hare produced at a greater rate since the shutdown than immediately preceding it.

Jan 1, 1940

Engineering Experiment Station, Kansas State College, Manhattan, Kansas. For publications or a list of publications, address the above Of the 29 Bulletins issued by the Engineering Experiment Station, a few on cement and road-building materials may well be listed here: Bulletin 12, Road materials of Kansas; 15, Tests of Kansas road materials, 17, Some strength characteristics of portland cement; 25, Volume change of concrete, 26, A study of fourteen brands of standard portland cement and four early-strength concretes, 28, The durability of concrete, 29, The effect of aggregate and other variables on the elastic properties of concrete

Jan 1, 1933

By M. F. Trice

PYROPHYLLITE is a hydrous aluminum silicate (A12Si4O10(OH)2)1 that occurs in both the foliated and the massive forms. The foliated variety resembles talc in that it has a greasy feel, a pearly luster, perfect basal cleavage, and usually is white, although in some deposits apple green, gray, brown, russet, and nearly black specimens may be found. The massive deposits of pyrophyllite yield pearl gray to light tan aggregates, some of which are so friable that they may be crushed with the hands into a fine gritty powder. Frequently specimens of the massive variety are studded with crystals of radial structure. The mineral has a specific gravity of about 2.7 and a hardness of 1 on Mohs' scale.1 The chemical composition of commercial pyrophyllite reflects the mineralogy of the deposits, which, according to Stuckey,2 contain pyrophyllite and quartz, together with chloritoid, sericite, and a few other minerals of negligible importance. The latter, he says, "are noticed in but small quantities to the extent they might occur as accessory constituents of an igneous rock or as products of regional metamorphism or weathering. . . . Quartz is abundant everywhere except in the very best grades of pyrophyllite." Analyses of specimens from several deposits are listed in Table 1, showing that the silica content varies from 57 to 73 per cent and the alumina from 22 to 33 per cent. Oxides of iron and the alkaline metals are collectively present, with one exception, to an extent of about 1 to 1.5 per cent. SOURCES At present, North Carolina is the only commercial source of pyrophyllite, although the mineral has been found in small quantities in many parts of the world. The North Carolina deposits are in the "Carolina Slate Belt," which traverses the center of the state in a southwesterly direction. This

Jan 1, 1940

By E. L. Kapfer

A preliminary description is made of the field of automation and optimization of the oxygen blast furnace process. The concept of static and dynamic process control is illustrated. After a short general description of all factors concerning the optimization of this process, a learning system is derived which gives better results than models previously used. This learning or self-adaptive control system uses statistical methods with exponential aging of process data and requires derivation of multi-variable functions of the process for which measurements can be made available. The practical application of this new procedure and of additional measuring instruments are discussed, and results obtained in plants using the adaptive control system are described. A survey of European steel plant automation using the Siemens technique is presented.

Jan 1, 1969

By William H. Pettee

A few weeks ago the Institute lost, by death, from its list of members one who in recent years, by frequent attendance at meetings, by the preparation of papers, and in many other ways, had shown a warm interest in Institute affairs; who had an extensive acquaintance among his fellow-members, and whose memory it is fitting to perpetuate by a permanent record in the volumes of our Transactions. Dr. Byron William Cheever, acting Professor of Metallurgy in the University of Michigan, died at his home in Ann Arbor, on the 6th of March, 1888. He was born September 17th, 1841, in Ellisburg, Jefferson County, New York. In 1844, the family moved to Geneva, Illinois, and thence, in 1857, to Dundee, Michigan. Two years later, a third removal was made to Ann Arbor to take advantage of the educational facilities there offered; and in 1859 the subject of this sketch, with his two brothers, entered the University of Michigan. In 1863, he took the degree of Bachelor of Arts. After a year or two of business life, he entered the medical department of the University, and graduated as Doctor of Medicine in 1867. A taste for scientific work had been developed in him in early life; and, even while carrying on undergraduate and medical studies, his proficiency in chemistry found recognition in his occasional employment as assistant in the University laboratory. The interval between the close of his course in Arts and the commencement of his course in Medicine was also devoted to chemical work, partly in the city of Philadelphia, and partly in the West Indies, where he was employed in the service of a commercial company engaged in the guano trade. Dr. Cheever never took up regular practice as a physician. After receiving his medical diploma he went again to Philadelphia, and for about two years was employed as an analytical and consulting chemist in that city. A favorable opportunity occurring for work in the Rocky Mountain mining region, he left Philadelphia and

Jan 1, 1888

By C. Ernest Birchenall

As a basis for further progress in several branches of metallurgy, particularly the study of physical properties of solid solutions and the kinetics of solid-solid reactions, a more complete understanding of the structure of solid solutions and the nature of the metallic bond is necessary. Any investigation contributing to this understanding should be of primary interest to the metallurgist. Since the metallic bond is characteristic of an assemblage of atoms, it can be studied only where this assemblage exists. One of the most promising approaches to this study of the interactions in metals is through the general problem of binary metallic solutions. Although crystal structures of many solid metallic solutions have been determined and solubility limits for many systems are given in phase diagram studies, progress beyond this is irregular. Electromotive force and vapor pressure determinations have provided thermodynamic activity data for small concentration and temperature ranges in the amalgams and a few other systems.1 In two systems, however, copper-zinc and iron-carbon, data are available for the calculation of activities over wide ranges of temperature and concentration. This activity data for the brass system is summarized in. the preceding paper.2 A detailed study of the solubility and distribution of carbon in iron is given by Smith and Darken .3 Their treatment of interaction energies is applicable only to dilute interstitial solutions. The objectives here will be to derive from activity data given in the previous paper for the brasses and structural considerations as much new and detailed information as possible about the interactions between copper and zinc in metallic solid solution and the effect of these interactions in determining the short range structure of the equilibrium phases; that is, we shall investigate the energy of interaction between pairs of atoms of the same and different kinds, the deviations of the distribution of nearest neighbors from complete randomness, and show that the conclusions found are consistent with the observed behavior of the brass system. The method of treatment is fairly general for substitutional metallic solid solutions and will be applied to other systems. The determination of vapor pressures of the components of alloy systems is being undertaken in this laboratory to supply more data for this purpose. The information obtained from solid solutions may be extended by careful analogy to liquids as long as the metallic type of bonding is preserved. Since it will be necessary to employ the language of thermodynamics, a brief summary defining the terms used extensively in solution theory is given below.

Jan 1, 1947

By C. A. Hartnagel

The production of petroleum in New York state in 1942 amounted to 5,410,000 bbl. This represents an increase over each of the four preceding years, and, with the exception of 1937, is the largest production since the peak of over six million barrels in 1882, shortly after the discovery of oil in Allegany County. The oil industry in New York is virtually stabilized and there has been little or no exploration for new sources of supply in recent years. The boundaries of the present fields were established more than 30 years ago and since then no additional reserves have been found. Deep drilling for natural gas during the past 10 years both within and without the oil fields has failed to find oil in quantity below the present producing sands of Devonian age. Oil Since 1882, the New York fields have produced approximately 140 million barrels of oil. Of this amount, 65 million was produced up to the year 1919 by ordinary pumping methods; that is, without flooding by water or the use of other secondary-recovery methods. In the year 1919, when a law was passed making the use of water-flooding methods legal, the oil production, of the state amounted to only 851,000 bbl. In the 23 years since 1919, there have been produced in the state 75 million barrels, or 10 million more than in the previous 37 years, which included the period of flush production. Price.—On March 26, the price of crude oil was raised from $2.75 to $3.00 per barrel, hut this increase had little or no effect on the number of wells drilled. In the Allegany field, which accounts for three fourths of the state's oil production, 1259 wells were completed in 1942, 7 less than in 1941. The smaller number of wells drilled was not only due to the shortage of labor but also was caused by the fact that in water-flooding territory a definite program for drilling wells is followed, and the flush period of an oil well is not usually reached in time to profit by any given price increase. Daily Production.—All of the oil wells in New York state, some 21,000 in number, are small producers. The average daily oil production is 7/10 bbl. per well. Under good flooding conditions, a maximum production of 5 to 8 bbl, a day is reached about one year after the flood begins to act on the well. In 5 years the daily production usually is less than one barrel. Although most of the oil in New York is produced by flooding, an estimated 2500 old wells produce without flooding. Some of these produce as little as 1/20 bbl. a day and are pumped only at intervals. The small producing Wells are mostly on lands leased to the larger oil companies and later will be included in a flooding program. At present, they are pumped only because the owners of the land insist on the royalty. Government Aid Needed.—Because of its good lubricating qualities, New York oil is one of those for which there is an insistent and growing demand, but even at its present price of $3.00 per barrel, many of the operators are producing at a loss.

Jan 1, 1943

By C. A. Hartnagel

The production of petroleum in New York state in 1942 amounted to 5,410,000 bbl. This represents an increase over each of the four preceding years, and, with the exception of 1937, is the largest production since the peak of over six million barrels in 1882, shortly after the discovery of oil in Allegany County. The oil industry in New York is virtually stabilized and there has been little or no exploration for new sources of supply in recent years. The boundaries of the present fields were established more than 30 years ago and since then no additional reserves have been found. Deep drilling for natural gas during the past 10 years both within and without the oil fields has failed to find oil in quantity below the present producing sands of Devonian age. Oil Since 1882, the New York fields have produced approximately 140 million barrels of oil. Of this amount, 65 million was produced up to the year 1919 by ordinary pumping methods; that is, without flooding by water or the use of other secondary-recovery methods. In the year 1919, when a law was passed making the use of water-flooding methods legal, the oil production, of the state amounted to only 851,000 bbl. In the 23 years since 1919, there have been produced in the state 75 million barrels, or 10 million more than in the previous 37 years, which included the period of flush production. Price.—On March 26, the price of crude oil was raised from $2.75 to $3.00 per barrel, hut this increase had little or no effect on the number of wells drilled. In the Allegany field, which accounts for three fourths of the state's oil production, 1259 wells were completed in 1942, 7 less than in 1941. The smaller number of wells drilled was not only due to the shortage of labor but also was caused by the fact that in water-flooding territory a definite program for drilling wells is followed, and the flush period of an oil well is not usually reached in time to profit by any given price increase. Daily Production.—All of the oil wells in New York state, some 21,000 in number, are small producers. The average daily oil production is 7/10 bbl. per well. Under good flooding conditions, a maximum production of 5 to 8 bbl, a day is reached about one year after the flood begins to act on the well. In 5 years the daily production usually is less than one barrel. Although most of the oil in New York is produced by flooding, an estimated 2500 old wells produce without flooding. Some of these produce as little as 1/20 bbl. a day and are pumped only at intervals. The small producing Wells are mostly on lands leased to the larger oil companies and later will be included in a flooding program. At present, they are pumped only because the owners of the land insist on the royalty. Government Aid Needed.—Because of its good lubricating qualities, New York oil is one of those for which there is an insistent and growing demand, but even at its present price of $3.00 per barrel, many of the operators are producing at a loss.

Jan 1, 1943

By A. B. Kinzel

SILICON, unfortunately, is not in the same category as some other metals with respect to the absolute value of the highest purity material prepared. Tucker, in England, and Becket, in this country have devel-oped procedures for the purification of silicon, and Becket's process has made industrially available silicon of a purity of 99.8 per cent or better. However, even the term "silicon metal" may be a paradox to some people, although not more so than the term "amorphous" as applied to silicon. These terms come from commerce, and "metal" is used to distinguish industrially high-purity silicon from ferrosilicon, silicon-aluminum, and other high-silicon alloys. Alloys of iron and silicon with 95 per cent Si or less are known as ferrosilicon, with a designation of silicon content where necessary, and the terns "silicon metal" is invariably applied to the grades containing 96 per cent Si and higher. The Becket method of purification was referred to in a monograph on the Alloys of Iron and Silicon, and the Tucker procedure was described in some detail in that publication.1 In order to get silicon of still higher purity, a sample, prepared by the Becket method, analyzing 99.84 per cent Si, 0.020 Fe, 0.016 Al, 0.005 Ca, 0.025 C, 0.033 per cent 02, 0.006 H2, 0.006 N2, and 0.001 per cent Mn, was crushed to pass a 100-mesh sieve said further purified by a modification of Tucker's procedure. This modification differs from Tucker's method in that after treatment the 100-mesh alloy was centrifuged to remove the last traces of acid. Our directly determined analysis of this purified sample shows: Si, 99.952 per cent; Fe, 0.009; Al, 0.012; Ca, 0.003; C, 0.006; or 99.982 per cent. Silicon by difference equals 99.97 per cent. The variation between silicon by difference and silicon as directly determined is important. Although Tucker mentions the amount of insoluble matter in commercial silicon both before and after his treat-ment, he does not mention the existence of carbon in the alloy; neverthe-less, lie reports silicon by difference. Any final figure as to purity obviously results from agreement between direct determination and

Jan 1, 1939

By Michael B. Kahle, Fred J. Scheaffer

Production scheduling, along with production planning, provides projections of future mining progress and time requirements for the development and extraction of a resource. These schedules and plans are used by management as a means of attaining the following objectives (1) maintaining or maximizing expected profit, (2) determining future investment in mining, (3) optimizing return on investment, (4) evaluating alternative Investments, and (5) conserving and developing owned resources. The first four goals are generally concerned with mining costs, both capital and operating requirements, and as such, play an important role in production planning. However, this chapter is concerned with the fifth management objective of resource development in order to conserve and perpetuate the corporate entity. The following discussion is based on the premise that detailed economic evaluations and market surveys have been performed and analyzed and that the results indi¬cate a viable project.

Jan 1, 1979

By T. B. Massalski, C. S. Barett

THAT metals and alloys of the body-centered-cubic structure tend to become unstable at low temperatures is so nearly universal that any exceptions are worthy of special attention. Studies of the exceptions may disclose unrecognized examples of metastability or may shed light on the nature of some of the factors that stabilize the body-centered-cubic phase. Among the structurally analogous body-centered-cubic 3/2 electron compounds, the ß-phase in the Cu-Zn system deserves further attention for, although this phase is known to undergo partial mar-tensitic transformation on cooling below room temperature to the temperature of liquid nitrogen when the composition is less than about 42 wt pct Zn, it does not transform on cooling .when there is more than this amount of zinc present.1-4 The present authors recently found that an alloy containing 48.35 wt pct Zn could be transformed, however, if deformed severely at room temperature or lower temperatures.V his discovery led to the suggestion that the jerky flow of ß-brass single crystals6 and some of the unusual temperature variations of the yield strength and hardness are due to strain-induced transformation during the tensile tests. The present investigation is an extension of that work to cover the entire available range of compositions of Cu-Zn ß-phase alloys and certain interesting compositions of the ß-phase in the Cu-Zn-Ga system. Particular attention is given to the structure of the transformation product resulting from cold work, which is found to vary with alloy composition, and to the temperature range in which transformation can be induced in the various alloys. The composition limits of the body-centered-cubic phase in the Cu-Zn system, based on a recent review by Raynor7 and the precision determinations of Beck and Smith: are shown in Fig. la; in the ß region the alloys are disordered and in the ß region they are ordered. The rate of ordering is so rapid that a high degree of order is found in any of these alloys immediately after quenching. Experimental The nine binary and four ternary alloys of this investigation were prepared from cathode copper (99.99 pct purity), electrolytic zinc (99.99+ pct), and gallium (99.98+ pct). All alloys were cast in transparent Vycor tubing, homogenized at temperatures between 800° and 890°C, and quenched in water. Ternary alloys were cast in small amounts (-5 g) to predetermined compositions to fall along a line of constant electron concentration in the ternary system. Changes of weight during the casting operation of the ternary alloys were not greater than 1 part in 2500 from the intended nominal weights and therefore their compositions were accepted without chemical analyses. All binary alloys were cast in larger amounts (100 to 150 g), homogenized, and hot rolled after preheating to 800°C. The central portion of the rolled strip of each alloy was annealed for eight days and quenched in brine. All binary alloys were analyzed chemically. The compositions, heat treatments, and metallographic appearances of all alloys are tabulated in Table I. Various samples were subjected to heat treatment or cold work at several temperatures and were then examined metallographically or by means of X-rays. Specimens about 6x6x3 mm in size were examined metallographic ally to confirm the presence of the ß-phase after quenching. Cold work was introduced by fastening each sample between two pieces of steel, cooling the assembly to the desired temperature, and transfering it rapidly to a vise where moderate or severe compression was immediately applied. Cold working at liquid helium temperature was done by a chisel-shaped tool mounted on an X-ray spectrometer, described elsewhere.% A!! metal-

Jan 1, 1958

By Paul J. Bennett, James E. Castle

The kyanite minerals, including kyanite, silimanite, and andalusite, are anhydrous aluminum silicates with the formula Al2O3SiO2. lumortierite and topaz are also included in this group because they are closely allied in composition and thermal behavior. However, leither are mined commercially today. They ire typical metamorphic minerals which are found in metamorphic rocks on every continent. Kyanite minerals are prized chiefly for their refractoriness and are important components in a broad range of acid refractory products, especially in mortars and castables. World production of kyanite minerals is currently about 250,000 tpy and has been increasing at the rate of 3 to 8% a year for many {ears (Anon, 1972). While kyanite minerals lave widespread occurrence, the consumption of kyanite minerals is concentrated in the relatively few highly industrialized areas where refractories are manufactured, and which in turn are typically close to the major iron and steel producing regions of the world. Thus northern Europe, England, the United States, and Japan are the principal consumers of refractories and kyanite minerals. Of these countries only the U.S. is a significant producer. The largest use for domestic kyanite, both raw and calcined, is in the manufacture of refractory mortars, cements, castables, and plastic ramming mixes. In these applications kyanite constitutes from 10 to 40% of the mixture, the balance being refractory clays and coarser grog materials. A certain proportion of raw kyanite is used to offset the shrinking of the clay binder, whereas the calcined kyanite is used in the coarser sizes for body. Certain high grade refractory shapes and kiln furniture are composed chiefly of graded sizes of calcined kyanite bonded with a little ball clay. In most applications, however, kyanite is used only to fortify the mix or as a minor ingredient. Some manufacturers of mullite brick use domestic calcined kyanite for the fine-grained portion of the brick, but seldom in quantities exceeding 10% by weight. Kyanite is used by ceramic manufacturers of wall tile and sanitary ware to offset shrinkage and cracking after firing. Indian kyanite has traditionally been used to make the coarse grog sizes needed for the manufacture of mullite brick, and for the grog portions of mortar, cement, and castable mixes. It has been largely replaced, however, by synthetic mullite, high fired flint, and diaspore clay or calcined bauxite for other applications. Indian kyanite is available in lump as well as in granules and concentrates, as are sillimanite materials from India and South Africa. Andalusite is available as 8 mesh granules and as fines with chemical analyses not unlike those of domestic kyanites. From time to time and from place to place minor amounts of other aluminum silicate minerals such as dumortier- ite, topaz, and pyrophyllite have been made available at various prices and specifications, but have not been significant factors in the refractory industry. A mixture of kyanite and sillimanite of relatively fine grain-size and of low iron content was at one time offered to the molding sand industry by the Du Pont Co. as a byproduct from their deposits of heavy

Jan 1, 1975

By Edmund Newton

THE steel industry of the United States has depended in the past almost wholly upon imports for its supplies of manganese. Many of the important domestic sources yield ores leaner in their natural condition than the foreign ores the steel industry has been accustomed to use. To make them available, therefore, either' the ores must be concentrated or the practice of the steel industry modified. Roughly 25,000 T. annually of high-grade manganese ores are used for dry batteries, for chemical purposes, and in other ways; while approximately 750,000 T. are required for making steel. By present practice, every ton of steel takes an average of about 14 lb. (1.8 kg.) of metallic manganese. This is generally added to the steel in the form of an alloy, the standard alloys being the 80-per cent. ferro-manganese and the 20-per cent. spiegeleisen. During the year 1917 286,000 T. of ferromanganese and 193,291 T. of spiegeleisen were made in this country, the former largely from imported ores; and 45,381 T.

Jan 2, 1919

By Andrew Corry

GEOPHYSICAL investigations based on radioactivity have been applied to the earth's crust for the purpose of discovering bodies rich in radioactive substances, or for the location of solutions with high emanation or radioactive-salt content, or for the detection of oil, which, in virtue of colloidal properties, has strong powers of radioactive absorption. RADIOACTIVE SUBSTANCES Radioactive substances are distributed in all rocks, waters, and gases in the earth's crust in small quantities. Granites and similar acidic rocks are richest in uranium and thorium, two chief radioactive substances; yet the quantities present in such rocks are of the order 10-12g., this concentration being expressed in grams per gram of the whole substance per cubic centimeter. In granites the uranium yields, according to Haddock, 3 X 10-12 g. of radium per gram of rock. In basalts the uranium yields 1.19 X 10-12 g. per gram per cubic centimeter. Of thorium the granites yield -2 X 10-5 g. per gram of rock; the basalts, 0.77 X 10-5 g. per gram. Certain series of alkalis of low atomic weight, like potassium and rubidium, show weak radioactivity; this property has no significance so far for geological research. The uranium is esti-mated indirectly from the electrical properties of one of its derivatives as a -gas (emanation) into which it is transformed. The thorium is expressed directly, though it is measured as a derivative, thorium emana-tion. There is a measure for the gaseous radium emanation, the curie, which is that quantity of radium emanation, or radon, which stands in equilibrium with 1 g. of radium. The concentration of the emanation is the Mache unit corresponding to 3.64 X 10-10 curie per liter. When gases become permeated by alpha, beta, and gamma rays, plus and minus ions are produced in them by the decomposition of neutral gas molecules, and under the influence of an electrical field these ions are given opposite motions. The measurement of the alpha rays and the bisection thicknesses of the beta and gamma rays is a means of analyzing unknown radioactive substances. These rays accompany the disintegration of radioactive substances and arise from "spontaneous internal changes

Jan 1, 1929

By William A. West

One manifestation of anelastic properties in solids is the mechanical elastic aftereffect, which may be described briefly as follows: If a stress is applied to a solid body, a deformation or strain is produced. On removal of the stress, this deformation disappears, at least in part. As a first approximation, this appearance or disappearance of deformation usually has been considered instantaneous. Actually, however, for a very wide variety of substances, on application of stress the instantaneous deformation is followed by a further slow yielding, which continues, although at a rapidly diminishing rate, for as long as the stress is applied. Similarly, on removal of the stress, the instantaneous recovery from deformation is followed by a further slow recovery, which continues, although at a rapidly diminishing rate, often for a long time. This latter phenomenon has been called the "elastic after-effect." Experiments upon the elastic after-effect in metals, when properly designed and when properly interpreted, are capable of giving quite precise information regarding the relation between stress and strain in the various constituent parts of the metal. For example, if certain parts of the metal, such as grain boundaries or slip bands, behave in a viscous manner—that is, if therein—the relaxation spectrum will contain lines or bands associated with the relaxation of shear stress within these parts. No attempts have heretofore been made to utilize elastic after-effects for obtaining such detailed information. The purpose of the present paper is to explore the possibilities of properly designed and interpreted experiments on the elastic aftereffect in metals. Since new procedures and principles are employed in this study, an attempt has been made to record each step taken. Elastic after-effect observations are susceptible of simple interpretation only when the stress level employed is so low that all effects are linear with the stress. Just how low the stress level must be can he determined only by experiment. An advnntage, other than simple interpretation, is associated with low stress levels. When all effects are linear, derived quantities, such as the relaxation spectrum, are independent of the stress distribution. It is, furthermore, possible to employ the type of deformation that is most convenient from the experimental standpoint; for example torsion. It appears that in experiments involving both loading and unloading the following would be observed: I. Instantaneous deformation, recoverable instantaneously in whole, or in part. 2. Delayed deformation, recoverable slowly in whole, in part, or not at all. 3. Permanent deformation, the difference between total deformation and total recovery. In the work here described, unloading experiments only were made. Wires were

Jan 1, 1947