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By Oliver Bowles

DISCUSSIONS of trade and commerce are generally more comprehensive today than in the past; the problems are approached with a vision unrestricted by national boundaries, and broad enough to comprise the entire world. The extent to which the limited viewpoint that has characterized past ages is yielding to an economy of world-wide scope is exemplified by the Atlantic Charter which blazes a trail in the direction of trade principles that aim to preserve the interest of each individual country in the commonwealth of nations. Its fourth article promulgated the principle that all nations should have access on equal terms to the trade and to the raw materials of the world which may be needed for their economic prosperity. Future developments in reciprocal international trade may have some effect upon the flow of nonmetallic minerals but such effects are not likely to be great because tariffs and trade policies have not affected that flow profoundly in the past. Nevertheless conditions may change and new problems may arise demanding important decisions. Sudden changes are not to be expected, but rather an orderly evolution in which national interests will merit due consideration in establishing broader policies.

Jan 1, 1945

By C. S. Smith

QUANTITATIVE methods were used to good effect in the earliest days of metallography1-3 but they mysteriously passed into virtual disuse until the important paper4 by Howard and Cohen in 1947. Various devices for the measurements of integrated linear intercepts have been constructed, primarily by petrographers. The hydraulically operated stage designed by the writer5 was satisfactory, but prolonged use caused air bubbles to become entrapped, which introduced back-lash. A new stage has been constructed which avoids this defect and provides better integration when measuring directional structures. This utilizes a circular traverse, and integration is achieved by counting electrical pulses produced by a photocell and a light chopper.* The stage is shown diagramatically in Fig. 1 and in photograph, Fig. 2. It is of simple construction. Mounted on a plate with clamps to fit the stage of a standard metallurgical microscope is a worm and 100-tooth worm gear, the latter supporting the specimen to be measured. The worm is manually actuated by a knob which contains inside it three

Jan 1, 1961

By Arthur B. Cummins, Henry Mulryan

DIATOMITE is a hydrous or opaline form of silica, commonly known as diatomaceous earth, diatomaceous silica or kieselguhr. The term "infusorial earth" has lost its original meaning and today is incorrect in view of the distinctions between diatoms and infusoria. Various locality and variety names are obsolete but some retain local significance. Moler and Celite are trade names that have become associated with diatomite products from certain deposits in Denmark and near Lompoc, California. COMPOSITION Diatomite is essentially silica with some combined water (2 to 10 pct). Frequently it contains organic matter (from traces up to over 30 pct) and varying amounts of inorganic impurities such as sand, cryptocrystalline silica, clay, volcanic ash, calcium carbonate, magnesia and soluble salts. In the natural or crude state, diatomite contains from 10 to 65 pct or more of free water. Table I gives analyses of several diatomites from deposits of different types. PROPERTIES Pure varieties, either massive or stratified, are friable and porous, of low apparent density, and somewhat chalklike in appearance. Varieties containing organic matter vary from sedimentary oozes to peatlike materials. Impure varieties may be more or less claylike, sandy, calcareous or cherty. Compacted types approach porcellanite and silicified shales. COLOR-white, cream, gray, tan, brown, greenish to nearly black. HARDNES-light-weight varieties appear 1 to 1.5 because of porosity, but microscopic particles are 4.5 to 6.5. SPECIFIC GRAVITY-1.9 to 2.35. APPARENT DENSITY---dry block form, 20 to 40 lb per cu ft; dry powder, 5 to 16 lb per cu ft. CRYSTAL SYSTEM-generally amorphous (isotropic by X-ray diffraction) but frequently showing faint cristobalite pattern.67.68,70 MELTING POINT-1400° to 1650°C. STREAK-white. LUSTER

Jan 1, 1949

By D. S. Rowley, F. C. Appl

Assuming that rock behavior, during cutting with a single diamond, may be approximated by that of a rigid, Coulomb, plastic material, a theory of single diamond cutting action has been developed. Using this theory, the stresses on the diamond cutting surface and the components of the cutting force have been determined. Theoretical results agree reasonably well with available experimental data. The theory of cutting of single diamonds may be used as the basis for subsequent study of the perfonnance of surface set diamond drill bits and other surface set diamond cutting tools. INTRODUCTION For more than twenty years, surface set diamond bits have been used successfully in the mining and petroleum industries to drill and core rock formations that range from medium hard to the hardest known formations. Most extremely hard rock formations cannot be economically drilled or cored by any other means. In view of the growing use and importance of surface set diamond drill bits, it is reasonable to study the way in which these tools cut, and the factors that influence wear of the diamonds. Such knowledge will contribute to better bit design and will improve operating procedures. To analyze the cutting performance of these tools it is appropriate to consider the way in which an individual diamond cuts. Once this is established, the over-all performance of the bits can be determined by considering the total effect of the individual diamonds. In recent years there has been a growing interest in rock mechanics and there now exist several publications dealing with the deformation and failure of rocks. Notable experimental work has been reported by Bredthauer,1 Handin and Hager,2, 3 and Gnirk and Cheatham.4 An extensive collection of data pertaining to rock properties at low confining pressures has been given by Wuerker.5 Cheatham and Gnirk have recently presented an excellent review of the state of knowledge regarding analytical and experimental rock deformation and failure.6 Generally rocks are extremely weak in uniaxial tension, and weak or only moderately strong in uniaxial compression. Both tensile failure and compressive failure are generally brittle in nature. This means that there is little or no deformation or "flow" of the material before shear or tensile fracture occurs. Thus, until fracture occurs, rock behaves very nearly like an elastic material in uniaxial stress. Significant changes in behavior of rock occur under conditions of triaxial compressive stress. There is generally a marked increase in compressive strength and in ductility. It has been demonstrated that the failure becomes plastic (in a macroscopic sense) at sufficiently high values of confining pressure. Sharp wedge chisel indentation studies conducted by Gnirk and Cheatham indicate that many rocks behave in a plastic manner at relatively low triaxial compressive stress states.4 If "failure" under triaxial compressive conditions is considered to be either complete rupture or macroscopic plastic flow, then the general failure characteristics of a rock can be reasonably well represented by the commonly known Mohr envelope. This certainly is not a perfect failure criterion (since the effect of the intermediate principal stress is neglected) but it has been found to be adequate for most engineering purposes. Mohr envelopes usually are constructed graphically using experimental triaxial test data. For purposes of analysis it is convenient to represent the envelope in equation form. Among the several approximate forms appearing in the literature, a parabolic form is suggested by Cheatham,7 and an exponential form is suggested by Paone and Tandanand.8 The exponential form has been adopted for this study, and based on published data, appropriate parameters have been established for 19 rock types. A typical plot of the data compared with the approximate envelope, and a summary of the rock properties and

Jan 1, 1969

By R. Schuhmann, J. Th. Overbeek, P. L. De Bruyn

W. E. Ewers (Commonwealth Scientific and Industrial Research organization, Melbourne, Australia)— Any attempt to elucidate further the meaning of the contact angle, particularly if it deals with the magnitudes of those mysterious quantities rsa and YRL, is certain to receive attention from those interested in the fundamentals of flotation. It is imperative, therefore, that attention should be drawn to a serious defect in the treatment by de Bruyn, Overbeek, and Schuhmann. Their Eq. 5 dy = — ld/u — Th2odiH2n states correctly the relationship between the change in surface free energy dy, the surface excesses Tx and Th2o of the components x and H2O and the changes du, and dph2o in the chemical potentials of these components. This equation applies for constant pressure and con- stant temperature and for the interface of the solid in contact with the solution of X. The relation remains valid when 1.1 is defined so that TH2O becomes zero and the equation becomes dr = — r:dur [17] From this equation de Bruyn et al. correctly concluded that increased adsorption of the collector at the liquid solid interface would reduce the interfacial energy ysl. Their second conclusion, however, that an increase in the contact angle, corresponding to a greater decrease in rsa than in rsL can be attributed to greater adsorption of X at the solid-air interface than at the solid-liquid interface is quite unjustified. The portion of the solid surface from which the collector solution has been displaced by air must be considered in terms of the equilibria between the gaseous phase and the surface. If the pressure and temperature

Jan 1, 1955

By G. E. Pralle

INTRODUCTION The decade from 1969 to 1979 saw the crest of a wave of investments by companies and investors, primarily from the major industrial nations, in the metals and minerals industries of the so-called lesser developed countries. This was brought about by two major considerations: 1). The higher ore grades and therefore the higher profit potential of the mineral deposits in the third world countries, and 2). The desire, particularly by the European countries and by Japan, to ensure a safe supply of raw materials not available in their own countries. The decade began with the start of the Toquepala mine in Peru and the major investments in the Bougainville mine in Papua New Guinea and the Ertsberg mine in Indonesia. It ended with the start-up of Southern Peru Copper Company (SPCC) Cuajone mine in Peru and Inco's Soroako mine in Indonesia and the investments in several major alumina or aluminum projects in Australia and Brazil. Concurrent with this huge flow of funds into the mineral resources industry of the developing world was the build-up of a psychological fear in the host countries of exploitation/domination by the foreign investors. This resulted in an increasing trend towards: 1). Nationalization of existing mineral ventures, and 2). Tougher legal/fiscal frameworks for new ones. NATIONALIZATION Nationalization appeared in its earliest form as "Mexicanization" of the petroleum industry in Mexico in the 1930's, followed later by Mexicanization of the mining industry in general. This was enacted with the Mexican Mining Law of 1961 which required that 51% of the equity be owned by Mexican nationals. Later in the decade the equity share for foreign investors was reduced to 33 1/3% for the developers of the Frasch sulphur operations in the Isthumus of Tehuantepec. However, the law was not fully implemented in the copper industry until late 1970 with the purchase of 51% of the ownership in the Cananea Mining Company. The trend toward nationalization of the copper industry progressed to Chile where in 1967 under the Government of Eduardo Frei the major North American copper companies were induced to sell a one-half interest in their Chilean mines to the State. Likewise, in 1970, "Zambianization" took place, when the two major operating companies Roan Selection Trust (Amax) and Zamanglo (Anglo American) were restructured into Roan Consolidated Mines (RCM) and Nchanga Consolidated Mines (NCCM) providing the government with 51% of the equity ownership. Whilst the earlier forms of nationalization in general constituted a fairly priced buy-out (El Teniente, Chile for US$80 million, RCM for US$117.8 million, NCCM for US$178.7 million), the total nationalization of the Chilean mining companies in 1970 under Salvador Allende did not. Later, "Western" countries joined this trend and on October 29, 1973, Mr. Gough Whitlam proclaimed that "overseas capital must continue... in partnership with Australian capital" and "in some special energy cases we have an objective of 100% Australian ownership". In 1974 Mr. Pierre Trudeau stated: "The Liberal Party of Canada sets as an objective that new resources projects in the natural resource field should have at least 50% and preferably 60% Canadian equity ownership". FOREIGN INVESTMENT The situation for the foreign investor in the worldwide resource industry rapidly deteriorated from then on. New features appeared in mineral exploitation and operating agreements, centering not only on local government/local companies ownership but also on increased taxation. The new tax rate (mineral tax, royalty, and income tax) for the semi-government companies NCCM and RCM in Zambia became an effective 73%. Likewise the much publicized and discussed renegotiated Bougainville agreement brought dramatic increases in the total "take" by the PNG Government. More innovative forms of indirect taxation made their appearance and were added to the normal tax burdens of the mineral industry which already

Jan 1, 1985

By Ray W. Amstutz

The shaft was drilled on US government land m the Piceance Creek basin and was funded by the US Bureau of Mines (USBM). It was drilled to 723 m to provide access to rich deposits of oil shale, nahcolite, and dawsonite for geotechnical test work and environmental mining research. Rotary drilling and dual-string, reverse-air, jet-assist circulation methods were used. Drilling required eight months. Site preparation, running, and cementing the casing required another four months. A 2.44-m ID steel welded casing, 508 mm thick was installed and 2.7 kt of cement were slurried and pumped into the annulus.

Jan 1, 1982

By Kent R. Van Horn, W. P. Sykes

Since Honda and Murakamil in 1918 proposed their constitutional diagram of the carbon-free iron-tungsten system, considerable effort has been expended by several investigators in attempts to define more positively the structural features of the alloys. The existence of an intermediate phase corresponding to the formula Fe3W2 (68.7 per cent W) was proposed from evidence of a purely metallographic nature by one of the present authors2 in 1926. Since that time the identity of this phase has been confirmed by Arnfelt3 and by Takeda,4 both of whom employed X-ray methods as well as the microscope and the chemical analysis of isolated microconstituents. According to Arnfelt, Fe3W2, as crystallized from the iron-rich melts at a temperature above 1450° C., contains by analysis 68.7 per cent W. The lattice of this phase is characterized by trigonal symmetry. Arnfelt, moreover, proposed a second intermediate phase formed at some temperature between 1450" and 1000" C. by a peritectoid reaction involving Fe3W2 and the iron-rich solid solution. A melt containing 25 per cent W was cooled to 1000" C. and heated for 100 hr. The precipitated tungsten-rich constituent was separated and found by analysis to contain 62.6 per cent W. This composition agrees closely with that represented by the formula Fe2W (62.2 per cent W). Diffraction patterns from the concentrated precipitate showed a hexagonal unit cell. Takeda confirmed the data of Arnfelt regarding Fe3W2 but was unable to detect Arnfelt's second intermediate phase. While Takeda failed to describe in detail the treatments employed, he stated that in alloys containing 40 per cent W which were quenched after heating at various temperatures between 1200" and 1450" C. no evidence of the second phase (Fe2W) was observed 'either in the microstructure or in the diffraction patterns of isolated residues. He therefore considered the existence of this low-temperature hexagonal compound as disproved.

Jan 1, 1933

By AIME AIME

Report of Committee 24, of the International Association for Testing Materials, presented at the Brussels Congress, 1906. Republished for use at the 94th Meeting of the American Institute of Mining Engineers, New York, N. Y., February, 1908. Discussion by letter is requested by the Secretary of the Institute. The Committee appointed for the solution of Problem 24 consisted of the following members Prof. H. M. Howe, New York, N. Y. (Chairman); L. Levy, Paris, France (Vice-Chairman) ; Prof. D. Tschernoff, St. Petersburg, Russia (Vice-Chairman) ; Prof. Albert Sauveur, Cambridge, Mass. (Secretary) ; Van Drunen, Ixelles, Belgium; Lieut.-Col. H. Tusen, Copenhagen, Denmark ; E. P. Martin, Abergavenny, England ; A. Pourcel, Paris, France ; H. Brauer, Dortmund, Germany ; Dr. Prof. H. Wedding, Berlin, Germany; P. Verole, Milan, Italy ; A. Baalsrud, Christiania, Norway ; A. R. v. Dormus, Vienna, Austria ; A. Sailler, Vienna, Austria; Bureau des Forges, St. Petersburg, Russia; Prof. N. Belelub-sky, St. Petersburg, Russia ; N. Jossa, St. Petersburg, Russia ; Maj.-Gen. M. Korobkoff, St. Petersburg, Russia ; S. Smirnoff, St. Petersburg, Russia ;.Ladislaus v. Tetmajer, Budapest, Hungary ; H. H. Campbell, Steelton, Pa. Early in February, 1905, a list of species and varieties of iron and steel, with definitions, drawn by the Chairman and Secretary of Committee 24, was sent to every member of this Committee with a request for comments and suggestions. A special request was sent to the following gentlemen . for the equivalents in their several languages of these species and varieties : A. , Pourcel, Paris, France; Prof. H. Wedding, Berlin, Germany ; J. A. Brinell, Stockholm, Sweden ; Prof. H. I. Hannover, Copenhagen, Denmark; Prof. P. Kley, Delft, Holland; P. Verole, Milan, Italy; Col. Cubillo, Trubia, Spain. This present report, which is based upon our original list and definitions, and upon the replies to these requests, consists of four parts I. A polyglot, which gives the names of the chief classes of iron and steel in English, French, German, Swedish, Danish and Dutch. We .regret that we have failed to get the Italian and Spanish names. II. English definitions of principal classes of iron and steel. III. A glossary of special sizes and shapes of iron and steel. IV. A note on the boundary between steel and cast-iron. I. POLYGLOT, IN ENGLISH, FRENCH, GERMAN, SWEDISH, DANISH AND DUTCH, OF THE CHIEF CLASSES OF IRON AND STEEL, AND OF THE APPARATUS IN WHICH THEY ARE MADE. This list is not intended to be complete, but rather to include only those varieties which are of interest to the Association.

Mar 1, 1908

By Homer F. Staley, C. P. Karr

The casting alloy 88 copper, 10 tin, 2 zinc, commonly known in England as Admiralty metal and in this country as Government bronze, gun metal, or Naval Department composition G, has, at its best, many valuable properties. However, its physical properties are known to vary widely with slight changes in method of manufacture of the castings, such as slight variations in composition, variation in pouring temperature, kind of mold used, method of pouring and gating of molds, size and shape of castings, amount and kind of heat treatment, and so forth.' The microstructure of castings made from this alloy is influenced by slight variations of composition, rate of cooling, and kind and length of heat treatment. This is best understood by reference to the equilibrium diagram. The part of the diagram in which we are interested and the effect of the thermal equilibrium relations on the physical properties of the alloy 88 copper, 10 tin, 2 zinc, have been discussed by Hoyt, Campbell, Primrose, and Rawdon.2 In Fig. 1 is given the equilibrium diagram of the copper-tin alloys. Briefly stated, the relations of composition and temperature changes are as follows. Compositions between A and a consist of but one constit ent—the a bronze, which is a solid solution of copper and tin, rich in copper. On cooling from the molten state these compositions gradually crystallize, at temperatures above 790°, into a mass of interwoven treelike crystals or dendrites. The cores of the dendrites are rich in copper and the percentage of tin gradually increases as the surfaces are approached. AS cooling progresses, after a11 the metal has crystallized, no further changes occur in the crystals other than diffusion within the crystals, which tends to erase the dendritic pattern and to render the structure more homogeneous. * Metallurgical Ceramist, U. S. Bureau of Standards, Associate Physicist, U. 8. Bureau of Standards. A. D. Flinn: Iron. Age (1915) 96, 1292-3. C. P. Karr: U. S. Bureau of Standards Tech. Paper 59, Pt. 1. S. L. Hoyt: Enging. (1913) 96, 667-7, 704-5. William Campbell: Trans. Am. Inst. Met. (1912) 6, 158-172. H. S. Primrose: Metal Ind. (1916) 14, 202-4. H. S. Rawdon: U. S. Bureau of Standards Tech. Paper 59, Pt. 11.

Jan 1, 1921

By C. E. Lundin, M. Hansen, D. J. McPherson

PRIOR work on the Zr-Cu phase diagram by Alli-bone and Sykes,' Pogodin, Shumova, and KUGU cheva,' and Raub and EngeL3 as confined largely to copper-rich alloys. The investigations of Raub and Engel were the most recent and seemingly the most complete of these. Alloys from 0 to 68.3 pct Zr were studied principally by thermal analysis and microscopic examination. These authors reported an inter metallic compound ZrCu, (1116°C melting point) and two eutectics, one at 86.3 pct Cu (977°C mp) and the other at 49 pct Cu (877°C mp). The solubility of zirconium in copper was reported to be less than 0.1 pct at 940°C. The zirconium melting stock consisted of Westing-house "Grade 3" iodide crystal bar (nominally 99.8 pct pure). It was treated by sand blasting and pickling (HF-HNO, solution) to remove the surface film of corrosion product, resulting from grade designation tests. The crystal bar was cold rolled to strip, lightly pickled again, and cut into pieces approximately 1/32 in. thick and 1/4 in. square. These were cleaned in acetone, dried, and stored for charging. The high-purity copper (spectrographic grade) was supplied by the American Smelting and Refining Co. with a nominal purity of 99.99 pct. These copper rods were rolled to strip, cut into squares the same size as the zirconium platelets, cleaned in acetone, dried, and stored. Equipment and Procedures The equipment used for melting and annealing the zirconium binary alloys and for the determination of solidus curves has been described in connection with previous work on the Ti-Si system' and in recent papers in this series describing the studies on eight binary zirconium systems.5-' Techniques employed for preparing and processing the alloys were also similar to those used in the above references. Ingots of 20 g were melted under a protective atmosphere of helium on water-cooled copper blocks in a nonconsumable electrode (tungsten) arc furnace. The ingots were homogenized and cold-worked prior to isothermal annealing to aid in the attainment of equilibrium. The specimens were heat-treated in Vycor bulbs sealed in vacuo or under argon, depending on the temperature of the anneal. Quenching was accomplished by breaking the Vycor bulbs under cold water. Temperature control was within ±3OC of reported temperatures. Thermal analysis was primarily relied on to determine eutectic levels, peritectic levels, and compound melting points. The induction furnace incipient melting technique was also used but did not provide the accuracy obtained by thermal analysis in this system, which involves much lower solidus temperatures than the other zirconium systems. A special technique for the determination of characteristic temperatures was employed in the case of several intermediate phases and their eutectics which displayed very small differences in melting temperatures. Specimens were sealed in Vycor bulbs and annealed at a series of very accurately controlled temperatures. Metallographic examination was then employed to reveal incipient melting. Furnaces and techniques in general were described previously.' The echant used was 20 pct HF plus 20 pct HNO3 in glycerine unless otherwise stated. Results and Discussion The chemical analyses of the majority of alloys prepared for the determination of phase relationships in this system are given in Table I and a brief summary of the equilibrium anneals employed is given in Table 11. In a preliminary program, alloys containing 1, 4, and 7 pct Cu were annealed for three different times at each of the temperatures 700°, 800°, and 900°C. No change in the relative amounts of phases present was detected after 350, 150, and 75 hr at the above temperatures, respectively. The times listed in Table II were accordingly chosen as a result of these preliminary tests. Zirconium-rich alloys containing from 0.1 to 10 pct CU were reduced by cold pressing from 58 to 8 pct, depending upon thk alloy content, homogenized for 7 hr at 900°C, and then reduced 80 to 13 pct by cold rolling, again depending upon copper content. Other alloys were studied in the cast, or cast and annealed conditions. The contracted scope of investigation for this system included the range 0 to 50 atomic pct Cu. This approximate region is shown in Fig. 1. Due to evidence of phase relationships departing considerably from those proposed by Raub and Engel" in the 50 to 100 atomic pct range, the investigation was extended to cover this composition area rather thoroughly also. Fig. 2 is a drawing of the entire diagram. The labeling of some phase fields was omitted in Fig. 2 for the sake of clarity. An expanded view of the zirconium-rich region, with the experimental points necessary for its construction, is given in Fig. 3. The generally accepted value of Vogel and Tonn8 or the allotropic transformation a + 862' ±5OC, was employed in the construction of these diagrams. A careful study revealed that the "Grade 3" crystal bar used in this investigation actually transforms over the approximate range 850" to 870°C, due to impurities. It must be expected that this two-phase field in unalloyed zirconium will cause some departures from binary ideality in the very dilute alloys. Zirconium-rich Alloys: The a + ß transformation temperature is decreased from 862" to about 822°C by increasing amounts of copper. Thus, a eutectoid reaction, fi ß a+ Zr,Cu, occurs at a composition of about 1.6 pct Cu. The eutectoid level was determined to lie between the alloy series annealed at 815" and 830°C. The placement of this eutectoid temperature

Jan 1, 1954

By D. F. Hewitt

Page Introduction..............................305 Geologic features of eastern Oregon....................306 Geology of the Sumpter quadrangle....................306 Rocks older than the ore deposits...................307 Rocks younger than the ore deposits.............. . Lodes of the Sumpter quadrangle..................312 Areal distribution.......................312 Geologic distribution.................... . Major features of the veins...................313 Mineralogy and texture of the veins.............. . Ore deposits zonally disposed around the Bald Mountain batholith . 317 Summary of mineralogy and texture.............336 Zonal relations......................337 Ore deposits zonally disposed around Greenhorn Mountain batholith. 340 Zonal relations..................... . Relation of textural features to zonal arrangement of veins.....341 Summary of zonal relations.................. . Comparison with similar districts................. . Outlook for the district......................344 Introduction In an earlier report on the Sumpter quadrangle1 it was briefly stated that the quartz lodes of that region might be separated into several groups or belts on the basis of the kind and abundance of the minerals of which they are composed, and that these belts were disposed as areal zones around the principal intrusive mass of the region. When the opportunity to revisit the region was offered in 1929, as a result of a cooperative agreement between the State Mining Board of Oregon and the United States Geological Survey, it seemed advisable to pay particular attention to this feature of the lodes, in the hope that if the idea of zonal relations was confirmed it might serve as a guide in exploitation.

Jan 1, 1931

By J. W. Clark, C. T. Sims

Wrought chromium-base alloys containing yttrium, cubic monocarbides of the Ti(Zr)C type, and similay alloys containing manganese and rhenium have been melted and fabricated. Strength has been studied by hot hardness and elevated-temperature tensile and rupture measurements, low-temperature ductility by tensile testing, and surface stability by oxidation testing. In additiod, studies have been conducted of the carbide stability, and of aging behavior. The carbide dispersion generates effective elevated-temperature strength, which is further enhanced hv strain-induced precipitation. The dispersion exhibits classical dissolution and aging response. The ductile-to-brittle transition temperature of these alloys is above room temperature. The alloys reported show fairly good oxidation resistance, but nitrogen contamination can cause fortnation of a hard Cr2N layer under the oxide scale. Manganese does not appear to be a promising alloying element in chromium. In the years 1945 to 1950, the metal chromium was considered as a possible base for alloy systems due to its considerably higher melting point than superalloys, its low density, its high thermal conductivity, and its apparent capacity for strengthening. However, this interest in chromium was short-lived. It was found difficult to melt and cast, to be exceptionally sensitive to the effect of minor imperfections, to have a lack of ductility at both room and elevated temperatures, and to be subject to a deleterious effect of alloying elements upon the ductile-to-brittle transition temperature.' Since then, chromium, as a practical alloy base, has remained virtually unstudied. Further, purposeful ignoring of chromium has been promoted by statements that its bcc structure would not allow it to be strengthened to useful values, when compared to the "austenitic" alloys.2 Recently, a new look has been taken at chromium-base alloy systems. Study of the literature will show that chromium, providing some of its disadvantages could be eliminated or minimized, actually has a rather attractive potential as an alloy-system base. Analysis of rather scattered data suggests that chromium is quite capable of being strengthened to high levels. Also, significant strengthening of its two sister elements in Group VI-A, molybdenum and tungsten, has been demonstrated in a number of commercial and exploratory alloys. Chromium should be similar. Since chromium does not readily form a volatile oxide like tungsten or molybdenum, it offers a much higher probability of giving birth to alloy systems with useful oxidation resistance. Concerns about possible high elemental vapor pressure have been mitigated by recent data.3 In addition, the physical properties exhibited by chromium are attractive for application as a high-temperature structural material. For instance, its thermal conductivity varies from 49 to 36 Btu-ft/hr-sq ft-°F over its range of usefulness (which is two to four times higher than most superalloys), its density is about 7.2 g per cc (20 pct less than most nickel-base alloys), its coefficient of thermal expansion varies from 4 to 8 x 10-6 per OF, and it has a relatively high modulus of elasticity, approximately 42 x 10' psi.4 Alloying studies on a chromium base in the past have usually encompassed rather sweeping solid-solution alloy additions for strengthening. This is not consistent with contemporary alloying practice in Group VI-A. For instance, molybdenum, also in Group VI-A, is primarily alloyed for strength improvement by use of heat-treatable carbide dispersions.5 Chromium and molybdenum are similar in their chemical activity and other properties. Thus, strengthening of chromium by carbide dispersions was studied. Chromium-base alloys are plagued with room-temperature brittleness, although high-purity unal-loyed chromium can be made ductile.4,8 Use of yttrium as a scavenger has done much to improve ductility and resistance to nitrogen embrittlement in chromium systems,7 so it was utilized in this program. It has also recently been found8 that small rhenium additions (1 to 5 pct) create improvement in the ductility of Type 218 tungsten wire. This is apparently related to the remarkable effect of rhenium additions near its terminal solid solubility in all Group VI-A metals.9'10 Investigation to establish if dilute concentrations of rhenium would also be effective in chromium appeared to be logical for this program. Since rhenium is too expensive to be practical in alloys for application as structural components, ductility improvements through solid-solution alloying were also sought by substitution of manganese for rhenium; manganese, like rhenium, exists in Group VII of the periodic system. The optimum amount of carbide dispersion for chromium-base alloys was obtained by analogy with molybdenum. Strengthening in molybdenum is achieved by use of Ti-Zr carbide dispersions. A

Jan 1, 1964

By L. Luini, E. Lee

An exploratory survey of the heat treatment response of commercial titanium alloys (Ti-150A, RC-130B, and MST 3AI-5Cr al-loys) shows a wide range of possible hardness and microstructural characteristics. The hardening is primarily dependent on the solid state transformation of the phase. An age hardening reaction which apparently is associated with ß decomposition and precipitation has been shown. Brittleness and notch sensitivity appear to be characteristic of age hardening to high hardness. Ductility, tensile strengths, and elongations are given. A NUMBER of commercially produced titanium-base alloys have been made available by the titanium metals industry. These alloys were developed to combine the light weight of titanium with increased strength through alloy additions. Usually the properties of these alloys are reported for material in the hot rolled and annealed condition. Since the production of commercial titanium has preceded the investigation of titanium-base alloy systems, the potential of these alloys is not well known. Although heat treatability has been indicated for these alloys, data on the response to heat treatment are quite limited. The heat treatability of titanium is based on the allotropic transformation of the high temperature, body-centered cubic ß structure to the low temperature, hexagonal close-packed a structure at approximately 1625 °F. This transformation in the pure metal is of little practical significance in heat treatment since the high temperature phase is not amenable to controlled transformation. Alloy additions serve to alter the transformation kinetics and permit control of the transformation by heat treatment variables. The effects of different alloys on the allotropic transformation in titanium classify them in two general categories,1 a stabilizing and ß stabilizing elements. The a stabilizers, represented by aluminum and oxygen, raise the temperature limits of the low temperature phase and introduce a two-phase a + ß temperature range. The ß stabilizers, represented by molybdenum and columbium, lower the equilibrium temperature of ß and give rise to an extended temperature range where both a and ß phases are stable. Another type of ß stabilizer, represented by iron, chromium, and manganese, introduces a eutectoid reaction. Some commercial titanium alloys belong to complex multiple element systems. Based upon the phase diagrams of the binary systems, the general effect of commercial compositions is to vary the stability of the high temperature phase and significantly alter its transformation characteristics. Therefore it is expected that the characteristics of alloyed titanium can be altered by heat treatment. The present investigation was undertaken to survey the variations in hardness, microstructure, and mechanical properties as affected by heat treatment variables. Commercial Alloys lnvestigated The commercially available titanium-base alloys selected for this investigation and obtained as 3/4 in. diameter hot rolled and annealed bars are listed in Table I. The producer did not determine the chemical composition of the Ti-150A heats X1052 and L685. The early heats of Ti-150A, prefixed with the letter X, were melted with tungsten-tipped electrodes and cast in approximately 500 lb ingots 12 in. in diameter. The heats prefixed with the letter L were melted under a revised melting practice yielding approximately 1300 lb ingots 16 in. in diameter. The final annealing treatment was at 1200" to 1250°F for 1 hr. The MST-3A1-5Cr alloy was melted in an induction furnace and cast in 7 in. diameter ingots. This practice produces high carbon material and some variation in the amount of carbides was found in different sections of the same bar. The RC-130B alloy was melted with a carbon arc. This alloy showed approximately 2 pct carbides. No large segregation effects were observed.

Jan 1, 1955

CONTENTS PAGE BARTON, D. C.-The Eötvös Torsion Balance Method of mapping Geologic Structure (T. P. No. 50) 1 GEORGE, P. W.-Experiments with Eötvös Torsion Balance in the Tri-State Zinc and Lead District (T. P. No. 65). 15 LANCASTER-JONES, E.-The Computation of Eötvös Gravity Effects (T. P. No.75) HEILAND, C. A.-A Cartographic Correction for the Eötvös Torsion Balance-(T. P. No. 52) 17 SLICHTER; L. B.-Certain Aspects of Magnetic Surveying (T. P. No. 120). . . . 18 WEAVER, W.-Certain Applications of the Surface Potential Method (T. P. No.121) LUNDBERG, H.-Recent Results in Electrical Prospecting for Ore (T. P. No. 98). . 20 HOTCHKISS, W. 0., ROONEY, W. J. and FISHER, J.-Earth-resistivity Measure-ments in the Lake Superior Copper Country (T. P. No. 82) 21 LEONARDON, E. G. and KELLY, S. F.-Some Applications of Potential Methods to Structural Studies (T. P. No. 115) 23 MASON, M.-Geophysical Exploration for Ores (T. P. No. 45) 25 The Eötvös. Torsion Balance Method of Mapping Geologic Structure Discussion of the paper of D. C.. Barton, issued as Technical Publication No. 50 with Mining and, Metallurgy, February, 1928. D. C. BARTON.-The field surveys which I have been privileged to use as illustrations for this paper were done for Mr. DeGolyer's companies and were released through his favor. W. J. MILLARD, Tulsa, Okla.-Has any oil been found by the torsion balance in West Texas? D. C. BARTON.-NO new oilfield has been discovered on the basis of torsion balance work. It has had some part in controlling the policy of certain companies in playing the extension of known oil fields. A number of "T. B." structures have been drilled and dry holes obtained. Of those known to the writer, one apparently was a structural high, one is a broad general high but locally low and probably is a deep-seated structural high, one seems normal although the control is poor, and one was considered structurally low but is now suspected by some geologists of being structurally high. E. L. DEGOLYER, New York, N. Y.-A large gravity structure, generally referred to, I believe, as the Crosby County Structure, has been found in West Texas. This structure is perfectly symmetrical with the arrows all pointing toward a common center, very much like the Nash salt-dome pattern in Dr. Barton's paper (Fig. 9). One of the peculiar things about it, from the standpoint of the gravity high, is that it is so

Jan 1, 1928

By John Hall

SOME months ago one of the authors was asked to write a paper on the heat treatment of steel castings that would be more comprehensive than other matter lie had published; this is an attempt to present in condensed form the results of experimental work and actual practice carried out for the most part in 1907, 1908; and 1909. It is not a laboratory research and the work done was carried out for the express purpose of putting in practice the processes discovered as fast as possible. Most of the tests are the result of commercial practice and not of bars annealed in our laboratory; most of the micrographs were made for our own records and not for publication. Certain of the micrographs, therefore, are not as clear as we may wish but they were good enough for our purpose at the time they were made. The tests and micrographs are selected from several thousands in our files. All of these micrographs are magnified 60 diameters. These experiments were conducted almost entirely on steel made in a 3-ton bottom-blown converter, and most of the steel illustrated analyzes about 0.05 in phosphorus and sulfur. Unfortunately, a certain number of specimens are shown of which we do not have the complete analysis, but in most cases in which the phosphorus and sulfur vary much from the figure just given that fact is noted. For purposes of comparison, we have included a certain number of micrographs and tests of steel made in the electric furnace, some of which were from specimens made in other shops and some in our own shop, and some tests of acid open-hearth and tropenas steel.

Jan 9, 1919

By Michael Tenenbaum

The importance of semikilled steel as a high tonnage grade has long been recognized. The increasing severity of the applications for which semikilled steel is used makes it desirable to obtain further information regarding the features of open hearth practice and ingot structure that can affect steel performance in subsequent rolling and fabricating operations. Accordingly, an investigation is being carried out studying the structure of various types of semikilled steel ingots. This paper reviews some of the observations made and information gathered in this investigation. By definition, semikilled steel may be considered to include all nonrimming steels in which the natural shrinkage occurring during ingot solidification is offset to an appreciable degree by gas formation. Accordingly, this type of steel includes the entire range intermediate between rimmed and fully killed steel. The resultant ingot structures range from those of steels that have been capped to suppress a weak rimming action to those steels that have been killed in the furnace or ladle to the extent that no mold deoxidizer is required. A survey reported to the 1946 -AIME Open Hearth Conference' reviewed the practices being used at 28 major plants for the deoxidation of semikilled steel. It was found that most plants divide the deoxidizing additions between the ladle and the mold—many of the plants adding only minor amounts of deoxidizer to the bath or none at all. Silicon, aluminum and titanium were the only elements used for ladle and mold deoxidation. Mold deoxidizers were added as capping additions or as uniformly fed additions. Several practices were reported in which the steel was deoxidized in the ladle to the extent that little or no mold deoxidation was needed. No reference was made to grades capped by using special mold designs or special closures over the top of molds. .Accordingly, specific examples of this type of practice will not be considered in this paper. It appeared from this survey of deoxidation practice that semikilled steel can be divided into three types, namely, capped semikilled, in which aluminum is added near the end of pour or after shut-off, intermediate semikilled steels, in which aluminum is fed uniformly throughout the pour, and semikilled steels requiring no mold deoxidation. In an attempt to cover the ingot structures obtained by the range of practices reported in the preceding survey, three series of experimental heats were made using increasing amounts of aluminum, silicon and titanium for ladle deoxidizers. The ladle deoxidizers were added as stick aluminum, 50 pct ferrosilicon and 20 pct ferrotitanium (4 pct carbon), respectively. Two methods of studying ingot structures were used. Ingots were removed from production, burned longitudinally and machined to allow observation of the central pipe and coarse blowholes. During the machining operation much of the finely porous subsurface structure was obliterated. Accordingly, observations were also made

Jan 1, 1949

By Michael Tenenbaum

The importance of semikilled steel as a high tonnage grade has long been recognized. The increasing severity of the applications for which semikilled steel is used makes it desirable to obtain further information regarding the features of open hearth practice and ingot structure that can affect steel performance in subsequent rolling and fabricating operations. Accordingly, an investigation is being carried out studying the structure of various types of semikilled steel ingots. This paper reviews some of the observations made and information gathered in this investigation. By definition, semikilled steel may be considered to include all nonrimming steels in which the natural shrinkage occurring during ingot solidification is offset to an appreciable degree by gas formation. Accordingly, this type of steel includes the entire range intermediate between rimmed and fully killed steel. The resultant ingot structures range from those of steels that have been capped to suppress a weak rimming action to those steels that have been killed in the furnace or ladle to the extent that no mold deoxidizer is required. A survey reported to the 1946 -AIME Open Hearth Conference' reviewed the practices being used at 28 major plants for the deoxidation of semikilled steel. It was found that most plants divide the deoxidizing additions between the ladle and the mold—many of the plants adding only minor amounts of deoxidizer to the bath or none at all. Silicon, aluminum and titanium were the only elements used for ladle and mold deoxidation. Mold deoxidizers were added as capping additions or as uniformly fed additions. Several practices were reported in which the steel was deoxidized in the ladle to the extent that little or no mold deoxidation was needed. No reference was made to grades capped by using special mold designs or special closures over the top of molds. .Accordingly, specific examples of this type of practice will not be considered in this paper. It appeared from this survey of deoxidation practice that semikilled steel can be divided into three types, namely, capped semikilled, in which aluminum is added near the end of pour or after shut-off, intermediate semikilled steels, in which aluminum is fed uniformly throughout the pour, and semikilled steels requiring no mold deoxidation. In an attempt to cover the ingot structures obtained by the range of practices reported in the preceding survey, three series of experimental heats were made using increasing amounts of aluminum, silicon and titanium for ladle deoxidizers. The ladle deoxidizers were added as stick aluminum, 50 pct ferrosilicon and 20 pct ferrotitanium (4 pct carbon), respectively. Two methods of studying ingot structures were used. Ingots were removed from production, burned longitudinally and machined to allow observation of the central pipe and coarse blowholes. During the machining operation much of the finely porous subsurface structure was obliterated. Accordingly, observations were also made

Jan 1, 1949

By M. C. Fuerstenau, A. M. Gaudin

A homogeneous suspension is viewed by X-rays. The radiation density seen, affords a measure of the extra absorption due to the solids contained. This radiation density, at a predetermined depth, varies with time. The chart of this relationship gives the desired determination. s it is frequently necessary to know the distribu-rt tion of particle sizes in various products used in industrial applications, a number of means have been devised for these determinations. Some of them include direct microscopic measurement, screening of product, extraction of samples from a settling slurry, air and liquid elutriation, adsorption of gases and liquids, and light absorption. The absorption of light as a means for particle size analysis has been known and employed for some time. X-ray absorption has not received the attention that light has enjoyed primarily because of the complex and costly instrumentation involved with X-rays. In 1954, Brown and Skrebowskil suggested the use of X-rays for this type of determination but did not supplement their suggestion with experiment. In 1958, the authors conducted size analysis experiments on suspensions of quartz with the Trans-viewer: an X-ray unit specifically adapted for sedimentation research, and Rossa conducted experiments in a similar manner in 1959 with a stable gamma emitter, AmZ4l, on suspensions of uranium oxide. To illustrate the applicability of X-ray absorption for analyzing particle size distributions, an essentially mono-energetic and well collimated X-ray beam was used as a source. The beam was made mono-energetic by placing a zirconium filter before the counting window together with feeding the pulses from the proportional counter into a reverter, a device capable of discriminating against pulses of various heights. The sketch in Fig. 1 shows the collimation arrangement in more detail. As shown, the X-ray beam was collimated by inserting a 3/8-in. ID pipe into one of the ports of the X-ray tube and further by two small steel plates with slits 3/32-in. wide and 1/2-in. long placed in front of the window of the Geiger-Mueller (G-M) tube. One of the plates was located 1/2 in. and the other 2 1/2 in. from the window of the counter; both plates were contained in an aluminum holder mounted on the box containing the G-M tube. This type and degree of collimation should eliminate any intensity due to scattered radiation; the transmitted intensity would then be solely a functior. of the absorption by the suspension at that level. Experimentally, homogeneous suspensions of finely ground quartz were prepared, Daxad (a sulfo-nated compound made from wood) was added as dis-persant, and the transmitted X-ray intensity measured as a function of time at a fixed depth in the suspension. In more detail, the experimental procedure involved the following: 1) measuring the transmitted X-ray intensity through the Daxad solution at a predetermined position or settling depth in the absence of solids, 2) placing a known amount of dry solids into the vessel and agitating thoroughly, 3) measuring the transmitted X-ray intensity at time zero (i.e., immediately upon cessation of stirring), and 4) measuring the transmitted X-ray intensity as a function of time (a 10-sec counting interval being chosen and counting being started 5 sec before the desired time). Since a linear relationship exists between percentage solid in a slurry and the logarithm of transmitted intensity for a homogeneous material, the cumu-

Jan 1, 1961

By Edgar R. Kendall

A KNOWLEDGE of the fundamental principles of locating, sampling, testing and evaluating materials is essential in prospecting for mineral aggregates. In this discussion, mineral aggregates will be considered sand, gravel, crushed stone and slag that are used as materials of construction. The quantity of mineral aggregates produced in the United States during the year 1935 for such purposes was roughly 165,000,000 tons, about 60 per cent of which was sand and gravel, 37 per cent crushed stone and 3 per cent crushed slag. The total value of this material was approximately $100,000,000. It is apparent therefore that the prospecting for suitable mineral aggregates is of considerable economic importance. In prospecting for mineral aggregates, the methods employed are the same whether the organization is large or small. In the large organization there may be available geologists for locating sources of supply, a land acquisition department to arrange for the necessary options or permits, engineers to do the sampling, a laboratory for testing, and a board of consulting materials engineers to make the final selection. Even small organizations must follow the same general procedure, though the responsibility for the selection of aggregates may rest with one man, who may or may not be an engineer, but who must depend entirely upon his own judgment. LOCATING THE SUPPLY The initial step in prospecting for mineral aggregates is the locating of suitable, adequate and economic sources of supply for the project in mind. Commercial plants in the vicinity should be investigated and a survey made of the existing structures that have been built of aggregates from these sources. If the structures are rather old and show no signs of deterioration, it is fairly good evidence that the aggregate is satisfactory. If materials of the proper quality can be obtained from commercial sources in sufficient quantity, and delivered to the job economically, it

Jan 1, 1939