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By H. E. Howe, A. A. Smith

The creep properties of lead alloys have been studied by a number of investigators but most of the work has been done on extruded material and the amount of data available on rolled alloys is surprisingly limited. Greenwood1 and his collaborators investigated various rolled commercial leads containing relatively small amounts of impurities, Phillips2 likewise studied rolled commercial leads, although he did include a few alloys— such as tellurium lead and one per cent antimonial lead. But as far as the authors are aware no data on the creep properties of so-called "hard leads"-—i.e., containing from 4 to 8 per cent antimony—have been published. In this paper some data are presented on a few antimonial lead alloys and compared with a copper-bearing lead. Preparation OF Specimens All the alloys used in this investigation were cast at a temperature of 400°C. into an open cast-iron mold preheated to Ioo°C., the resultant casting being % by I by 10 in. The copper-bearing alloy was cold-rolled by 10 per cent passes to a thickness of 0.100 in. Creep specimens 16 in. long were prepared by clamping the strips between wooden blocks and machining the edges of the strips parallel by means of a plane. Careful manipulation gave parallel specimens with no reduced section and with a minimum of distortion. The antimonial lead castings were hot-rolled in 10 per cent passes at a temperature of I50°C. to a thickness of 0.400 in., the heating being carried out in an electric oven after each pass through the rolls. After the castings had been broken down to 0.400 in., they were allowed to cool to room temperature and then cold-rolled to 0.100 in. with the usual Io per cent passes. Sufficient time was allowed after each pass for the strips to cool to room temperature. The apparatus and method of measuring strain have been adequately described in a previous paper3 and essentially the same practice was used in obtaining the present data. Time-extension curves for only two alloys are given, since these are typical of all. Figs. I and 2 show the time-extension Curves for the copper-bearing alloy A at 30°C. and loo°C., and Figs. 3 and 4 show

Jan 1, 1945

By John J. Egan

THE present list of problems relating to the physical chemistry of steelmaking has been prepared by the Committee on the Physical Chemistry of Steelmaking, from answers to a questionnaire Submitted to a number of metallurgists engaged in both industrial and educational work throughout the United States. The purpose of the project is to make available to research laboratories a list of problems, all reduced to their simplest terms, the solution of which would aid in creating a better understanding of the steelmaking process. It is not intended to restrict the problems to practical steelmaking. The list also includes the study of the properties, and their correlation, as well as the physical and chemical reactions, of all Substances that occur or that may be in any way associated with steelmaking operations, Such as metallic substances, refractories, nonmetallic inclusions, and the constituents of slags. Many of the problems can be carried out in university or other research laboratories. Others may be most successfully attacked by cooperation of the research men with the operating personnel. It is the Committee's earnest wish that this cooperation be fostered. It is requested that investigators who are working on any of the problems listed and who anticipate future publication of their results, notify the Secretary of the Committee that such investigation is in progress. Suggested additions to the present list are also requested. The Committee is undertaking to act as a clearing house for information regarding the topics in this field that are being actually studied. Interested persons are invited to correspond with the Secretary. I. Data involved in the state of equilibrium for the various systems (laboratory work, almost entirely). A. SPECIFIC HEATS, HEATS OF FORMATION, ENTROPIES AND FREE ENERGIES OF VARIOUS PURE ELEMENTS OR COMPOUNDS; ALSO CERTAIN TYPICAL SLAGS AND REFRACTORIES. I . Determination of specific heats and entropies of oxides, sulphides, nitrides, etc. over a wide temperature range. 2. Determination of free energies of oxides, sulphides, nitrides, etc. over a wide temperature range. 3. Determination of the heats of formation of the oxides, sulphides, nitrides, etc. 4. Determination of the thermodynamic properties of the more important mineralogical constituents of the basic open-hearth slags such as calcium silicates, calcium phosphates, calcium ferrites, manganese silicates, FeO and Fe2O3. 5. Determination of the specific heats of open-hearth slags, including liquid silicates, if possible.

Jan 1, 1941

By Sheldon Rideout, E. L. Kamen, B. S. Lement, Paul A. Beck, W. D. Manly

The 1200°C isothermal sections of the following ternary phase diagrams were investigated: Cr-Co-Nil Cr-Co-Fe, Cr-Co-Mot and Cr-Ni-Mo. In all these systems the u phase was found to form extended solid solutions. Two new ternary phases of unknown structure were identified. The existence range of intermediate phases of transition elements was correlated with 3d electron vacancy concentrations. THE occurrence of extensive ternary d solid solutions in the Cr-Co-Ni and in the Cr-Co-Fe systems was described in a brief note.' More recently d- solid solutions were also found in the Cr-Fe-Mo system by two independent groups of investigators.2,3 The existence of binary d phases in the V-Co and V-Ni systems, predicted in ref. 1, was experimentally discovered recently by Duwez and Baen and independently by W. B. Pearson, J. W. Christian, and W. Hume-Rothery.5 Duwez and Baen stated two general conditions for the occurrence of the d phase in alloys of the transition elements: "(1) The atomic diameters of the two metals do not differ by more than 8 per cent. (2) One of the two metals has a body-centered cubic structure while the other is face-centered cubic, at least in one of its allotropic forms." In the course of an extensive research program conducted at this Laboratory under the sponsorship of the NACA, several ternary systems, containing d solid solutions and also certain new ternary phases, were investigated. The present report describes the investigated portions of the 1200°C isothermal sections of the following ternary phase diagrams: Cr- Co-Ni, Cr-Co-Fe, Cr-Co-Mo, and Cr-Ni-Mo. It was found that the range of existence of the d phase in these four ternary systems, as well as in one of two ternary systems which were investigated by others, can be fairly consistently described in terms of electron vacancy concentrations. This supports the suggestion of Sully and Heal" that the d phase is an electron compound. Experimental Procedure The ternary alloys were prepared by vacuum induction melting in zirconia and alumina crucibles. Lot analyses of the metals used are given in Table I. Specimens of all alloys were annealed at 1200°C in an atmosphere of purified 92 pct helium and 8 pct hydrogen mixture. Alloys consisting mainly of

Jan 1, 1952

By Lester Guttman

THE connection between short-range order and thermodynamic activities in binary solid solutions has been pointed out by Birchenall1 who calculated approximate values of the energy of interaction of Zn and Cu and of the degree of short-range order in alpha-brass at one composition and two temperatures. The purpose of this note is to call attention to a somewhat more accurate theory than that used by Birchenall and to extend the calculations to a wider range of temperatures and compositions as a means of testing its applicability. This is an example of the well-known general method of comparing measured thermo-dynamic functions of a system with those calculated from a microscopic model by means of statistical mechanics. In this case, mathematical approximations must be used which make difficult any decision about the validity of the model. Birchenall's statistical method resembles closely that called by Fowler and Guggenheim2 the "quasi-chemical" method which has been shown to lead in certain cases to results identical with those obtained by the method of Bethe.3 The quasi-chemical method has been extended by Takagi4 to give general formulae for the free energy of binary solid solutions based on several lattices at all compositions and temperatures. Specifically, he treats the four systems typified by: I. ß-brass; 2. a- brass; 3. AuCu3; 4. AuCu. When the temperature is so high that no long-range order exists, these formulae reduce to the same form for all lattice types, namely: [ ] Here the symbols have the following meanings: [F-Helmholtz free energy E-energy S-entropy k-the gas constant per molecule z-coordination number, (e.g. 12 in. a-brass). N-total number of atoms c-atomic fraction of A] VAA, VBB, VAB-energy per bond of the corresponding bonds log means log, throughout The superscript 0 denotes the thermo- dynamic function in the standard state, which has been chosen to be pure A or B with the same crystal structure as the solid solution. The quantity x is the ratio of the number of A-A bonds to the total number and for minimum F satisfies the equilibrium condition [ ] The free energy may also be written in terms of µA and µB, the chemical potentials or partial free energies per atom:

Jan 1, 1948

By Stephen H. Stow

A relationship exists between the color and the chemical composition of the pebbles from the Bone Valley Phosphate Formation. Darker-colored pebbles are relatively high in iron oxide and relatively low in calcium phosphate when compared to lighter-colored samples; the brown color of the phosphate pebbles can be correlated with their iron content and the black and gray colors with their organic carbon content.1,3 It was anticipated that the darkness of a phosphate sample might be quantitatively measured by a simple reflectivity test and that the amount of reflected light could be correlated with the chemical composition of the rock, especially with the elements which cause the color and darkness of the Florida phosphates. Twenty-one samples of production grade phosphate rock from Hillsboro County, Fla., were studied. All samples were ground to -200 mesh for reflectivity tests and analyses. All analyses are accurate to well within ±2% of the reported value, except for aluminum and organic carbon, which are accurate to only ±15% of the reported amount. Reflectivity measurements were taken with a model 610 Photovoltmeter for tri-stimulus amber, blue and green, and white lights. Experimental procedures and data are available upon request. Results Table 1 contains linear correlation coefficients (LCC) for the element-reflectance relationships for the samples. The top portion of the table refers to the LCC between the percent of light reflected off the samples and the percent of a given element (or its oxide) as analyzed. In the lower portion of the table the LCC refers to the relationship between the same reflectance data and the chemical analyses which have been corrected on the basis of 0% acid insoluble material (chiefly quartz) in the phosphate rock. Each LCC presented in Table I is computed for the 14 coarser samples exclusive of the seven concentrates since the concentrate samples appear to have anomalous reflectivities upon comparison with the coarser grades. Only the most significant LCC for each element is presented in graphical form. Discussion of Data Iron: [Fig. 1] is a graph of the relationship between iron and reflectivity (LCC = - 0.98). A good correlation with Fe2O3, is expected due to the relationship between the tan (or brown) color and the abundance of iron oxide, the principal mode of occurrence of iron in Florida phosphates.8 Note the location of the seven triangles which repre-

Jan 1, 1972

By G. C. Weaver, G. T. Harley

BEDS or lenses of potash and magnesium salts are found in a thick salt section (Salado) overlain by Rustler Red Beds in several members of which water is present and from one of which the refinery process water used by International is obtained. Most of the holes drilled are less than 1000 ft. deep, but some wildcat holes have exceeded 3000 ft. Cable or rotary tools are used to drill down to the salt. When samples of water are desired the cable rig is used, but when this is not necessary, and where caving material is present, the rotary rig has an advantage. The rotary rig has a further advantage in that only one machine is required to drill and core the entire hole, whereas the cable rig must be moved off to make way for the core drill. Casing is placed in the upper section of the hole as required to shut off water, and a 5 3/16-in. string is set in the top of the salt before coring starts. With the rotary rig drilling is often carried to the salt with no casing, as drilling mud seals off caving ground and water-bearing strata, and a string of 4-in, line pipe or 4-in. flush-joint casing is landed on top of salt. Several types of gasoline-powered core rigs have been used in the field and all recover a 2 1/2-in. core. More recently the Sullivan Model 37 rotary rig has been tried, and a Sullivan Model N has been adapted to use a rotary bit in the upper section. Core is recovered in 20 ft. sections with a double-tube core barrel, and the bit used is a bottom-discharge type set with diamonds. The drilling fluid must be a saturated brine to prevent solution and etching of the minerals present. Blowouts are apt to occur from nitrogen gas trapped under the several polyhalite beds, and some have been strong enough to blow the tools out of the hole. Core recovery is practically 100per cent. All holes are plugged after drilling, with cement through the salt section and opposite each water horizon, and mud through the remainder of the hole. Cores are carefully logged and preserved, and in sections containing potash and magnesium minerals they are quartered and analyzed. The correlation of ore beds between drill holes is briefly described.

Jan 1, 1946

By J. Kittl, D. Arias

THE decomposition on cooling of the high-temperature ß bcc phases in copper- or silver-based binary systems usually takes place by a martensitic. massive, bainitic, or pearlitic reaction depending upon the particular conditions of each system. The AgAl system is one of these systems in which a massive or a martensitic transformation can occur upon cooling from the 3 phase field. Recently Hawbolt and Brown1 observed both massive and martensitic transformation products in a 22.7 at. pct A1 alloy. In the present work the massive and the martensitic transformations were investigated in a number of alloys for the composition range between 23.2 and 27.9 at. pct Al. The alloys were prepared using high-purity silver, 99.999 pct, supplied by ASARCO and aluminum, 99.999 pct, supplied by ALCOA. The metals were melted using a graphite or a sintered alumina crucible which was sealed in quartz tubes under an argon atmosphere. The alloys Were remelted to reduce segregation and homogenized in the 13 phase field for 24 hr. The weight of the alloys after homo-genization compared with the initial weight indicating the alloy composition to be within k0.1 pct of the in- tended composition. Chemical analysis of several samples confirmed the estimated alloy composition. All metallographic observations were performed on samples electropolished with ac current using a 10 pct solution of KCN and a stainless-steel electrode. The samples were cut into -1-mm-thick slices, polished, heat-treated in the ß phase field, and quenched in air, ice water, or iced brine. Some heat treatments consisted of a 2-min anneal carried out in air to allow maximum quenching speeds. Other samples were heat-treated in a vacuum of 10"4 torr and quenched using a helium blast in a quenching apparatus described elsewhere.&apos; In both cases, no appreciable losses of silver or aluminum were noted at the sample surface by sectioning and electropolishing. Table I summarizes the microstructure resulting from the various quenching treatments. The composition of the alloys investigated is also indicated on the equilibrium diagram in Fig. 1. The <, hcp phase, typical of a massive ß — cm, transformation, was observed in all alloys. A minimum temperature of 450°C was estimated for this transformation based on preliminary cooling experiments. the results being included in Fig. 1. In these

Jan 1, 1970

By Wilbur C. Helt

The United States is self-sufficient in bituminous coal and lignite resources to meet the high range of energy demands forecast for the remainder of this century and beyond. The known or proved recoverable reserves of energy from coal in the United States are estimated to be 88% of all fuel reserves, whereas the energy reserves for oil are estimated to be 276, gas 376, shale oil 5% and uranium 2% (as now used). The demand for all forms of energy used in the United States is increasing at a rate of 3% to 4% per year. Presently, coal is competitive on a supply and cost basis with other fuels in conversion to electrical energy and as a source of energy for converting raw minerals to metals and nonmetals, but it is not competitive in transportation and other uses that demand the high flexibility that oil and gas enjoy because of their form. Coal conversion to fluid forms is essential to make it interchangeable with gas and oil to meet the markets they now occupy. Essentially, the chemical constituents that make up coal are the same hydrocarbons that make up oil and gas; it is a matter of reconstituting the proportions of hydrocarbons to make coal interchangeable with the other fuels. The production of coal has fluctuated widely between the peak production of 631 million tons in 1947 to a low of 403 million tons in 1961. Throughout this period, the total value of the production, f.o.b. mines, has averaged more than $2 billion annually. Beginning with 1962, there has been a steady upward trend in coal production with only minor fluctuations that were mainly caused by labor disputes. Output for the latest typical year, 1970, was 588 million tons. Production in 1971 was affected by a major strike and dropped to 548 million tons. Exports of coal from United States to foreign countries have increased steadily and developed into a substantial annual market for over 71 million tons per year. About 56 million tons of this is suitable for metallurgical purposes, and the remaining 15 million tons is exported for electric power generation. The largest single-industry demand for coal is in the electric generating industry, Fig.1. Roughly, the production of electricity has doubled every

Jan 1, 1973

By Oliver B. Hopkins

Peru produced approximately 17,466,620 bbl., of oil during 1937, or slightly less than the record high of 17,593,700 bbl. established during 1936. As in 1936, the entire output of the country was derived from the La Brea-Parinas, Lobitos-Restin and Zorritos fields in the northwestern part of the country. Outside of the proven areas, drilling was &apos;continued by the Peruvian Government in the northern province of Tumbes on the reserved zone at Zorritos. Drilling was carried out on three locations, two of which are understood to have been abandoned during the year. In southern Peru, further attention was given by Government engineers to the Pusi and Saman districts and plans are being worked out for the commencement of drilling operations in the near future in the vicinity of Pirin. Activities in the montaiia region in eastern Peru were continued by the Compafiia Petrolera El Ganso Azul. This company acquired the interest of the Selden Breck Co., and holds some 90,000 acres along the Pachitea River a few miles above its confluence with the Ucayali. During the year, the preparation of a landing place, the cutting of a 12-km. (71/2-mile) road from the river to the drill site, and the construction of a camp were undertaken. Equipment for drilling on this company&apos;s concessions has already arrived in South America. La Brea-Parinas Estate.—Production of crude oil on the La Brea-Parinas Estate of the International Petroleum Company Limited amounted to 14,722,754 bbl. during 1937, a decrease of 403,736 bbl. from the all-time high reached during 1936. The total production from 1890 to Dec. 31,1937, was 178,390,767 bbl. During 1937, a total of 141,653 ft. was drilled, 129,516 ft. in new wells and 12,137 in deepening existing wells. In all, 57 wells were completed, 47 of which produced oil, 2 were gas wells and 8 dry. holes. Twenty-nine wells were cleaned out or deepened during the year. The average depth of new wells completed during 1937 was 2367 ft. compared with 1984 ft. for the new wells completed during 1936. There was an increased use of rotary tools during the year and this method is now used to a greater extent than the cable-tool method, which formerly predominated. Of the 57 wells completed during the year, 31 were

Jan 1, 1938

By George Watkin Evans

The need for mechanization in coal mining wherever it can be successfully introduced is evident when we take into account the fact that during recent years the coal-mine employee&apos;s wages have increased and his hours have been shortened. Coal is no longer King, and a brief study of statistics covering the production of coal, petroleum and natural gas and the development of water power will convince anyone that coal has had very powerful competitors during the past 10 years. Petroleum production in the United States between 1918 and 1936 increased from 100 per cent to 309 per cent. Water power increased from 100 per cent in 1918 to 270 per cent in 1936. Bituminous coal slipped from 100 per cent in 1918 to 75 per cent in 1936. The anthracite industry slipped from 100 per cent in 1918 to 50 per cent in 1932, but climbed to 55 per cent in 1936. In 1918, the State of Washington produced a little over four million tons of coal and the production of California oil, at that time, was a little less than one hundred million barrels per year. By 1929 the production of California oil had increased to a little over 292,000,000 bbl. or nearly 300 per cent as compared with 1918. By 1934 the production of coal in the state of Washington had dropped to about 1 1/3 millions of tons per year. Our neighbors in British Columbia had their coal production reduced from a little over 2 1/2 million tons in 1920 to less than 1 1/3 million in 1933. The North western Improvement Co., a subsidiary of the Northern Pacific Railroad Co., owns coal properties in various parts of Washington and Montana. The Northern Pacific is one of the very few railroads using any considerable quantity of coal in its operations. Practically all of the American railroads in the Pacific Northwest, except the Northern Pacific, are using cheap California fuel oil or electricity. This problem, of course, is not a new one in coal mining, and all of the progressive coal companies in the country have tried to meet competition from an overproduction of petroleum and an overproduction of natural gas as well as enlarged developments of hydroelectric plants.

Jan 1, 1938

By George Watkin Evans

The need for mechanization in coal mining wherever it can be successfully introduced is evident when we take into account the fact that during recent years the coal-mine employee&apos;s wages have increased and his hours have been shortened. Coal is no longer King, and a brief study of statistics covering the production of coal, petroleum and natural gas and the development of water power will convince anyone that coal has had very powerful competitors during the past 10 years. Petroleum production in the United States between 1918 and 1936 increased from 100 per cent to 309 per cent. Water power increased from 100 per cent in 1918 to 270 per cent in 1936. Bituminous coal slipped from 100 per cent in 1918 to 75 per cent in 1936. The anthracite industry slipped from 100 per cent in 1918 to 50 per cent in 1932, but climbed to 55 per cent in 1936. In 1918, the State of Washington produced a little over four million tons of coal and the production of California oil, at that time, was a little less than one hundred million barrels per year. By 1929 the production of California oil had increased to a little over 292,000,000 bbl. or nearly 300 per cent as compared with 1918. By 1934 the production of coal in the state of Washington had dropped to about 1 1/3 millions of tons per year. Our neighbors in British Columbia had their coal production reduced from a little over 2 1/2 million tons in 1920 to less than 1 1/3 million in 1933. The North western Improvement Co., a subsidiary of the Northern Pacific Railroad Co., owns coal properties in various parts of Washington and Montana. The Northern Pacific is one of the very few railroads using any considerable quantity of coal in its operations. Practically all of the American railroads in the Pacific Northwest, except the Northern Pacific, are using cheap California fuel oil or electricity. This problem, of course, is not a new one in coal mining, and all of the progressive coal companies in the country have tried to meet competition from an overproduction of petroleum and an overproduction of natural gas as well as enlarged developments of hydroelectric plants.

Jan 1, 1938

By F. D. Rosi

The slip and twinning behavior in extended titanium crystals were studied in some detail. The formation and appearance of coarse kink bands are discussed. Their crystallographic geometry was determined by X-ray analysis. A phenomenological interpretation of the complexities in kink band development is also presented. The critical resolved shear stress, coefficient of shear hardening, and plane of fracture were determined for several crystals extended at room temperature. THE slip and twinning elements observed in the room-temperature deformation of titanium were enumerated in a previous paper1 in which considerations were advanced regarding the nature and selection of these elements and their effect on the known mechanical properties of this metal. The present study concerns the crystallographic, microscopic, and mechanical aspects of flow in relation to the slip and twinning elements, and includes a prediction of slip systems, nature of slip and twin markings, inhomogeneities of plastic flow, and stress-strain characteristics. Unless otherwise noted, arc-melted titanium sponge (99.77 pct) was used in these experiments. The method of production of crystals, their dimensions, and the surface preparation for micrographic examination have been reported.&apos; For obtaining stress-strain characteristics, only those crystals which traversed the entire width of the specimen and were at least 8 mm in length were used. Tensile deformation of the crystals was performed with conventional grips for sheet specimens and a constant-stress loading beam, designed after the method of Andrade and Chalmers.&apos; The specimens were loaded by allowing sand to flow from a reservoir into a bucket suspended from the longer end of a balanced 6:1 lever arm at a rate controlled to load the specimen approximately 2 kg per min. Strain measurements were made using the Baldwin SR-4, bonded, resistance-wire strain gage, Type A-8, which permitted a reading accuracy of 2 microinches per inch. The formulas used in the evaluation of shear stress and shear strain, as in deriving the coefficient of shear hardening, are given by Schmid and Boasv n terms of the original orientation and change in length of the crystal. For calculating the critical resolved shear stress, the standard equation was used. The crystallographic nature of the unpredictable slip observed in a number of specimens was determined by the single-surface X-ray method of analysis as described in ref. 1. Experimental Results Prediction of Slip System: It was reported&apos; that room temperature slip in titanium takes place predominantly on {10i0} and in a <1120> direction, giving three potential slip systems. Hence, it should be possible to predict the operative primary system in the manner used by Taylor and Elam&apos; for alu- minum (i.e., the one with the greatest component of shear stress in the direction of slip). The stereo-graphic construction in Fig. 1 shows that this is true. In all cases, slip was found to occur initially on the (0110) plane and, in a number of cases, in the [21f0] direction. (The direction of slip was not determined for all orientations.) It follows that duplex slip can be expected when two slip systems are geometrically equally favorable for slip, as demonstrated in Fig. 2. In both crystals slip took place simultaneously on the (1700) and (olio) prismatic planes, as indicated by Fig. 2a and b. In the case of crystal B the movement of the specimen axis with increasing extension was toward the (10i0) direction, which represents the stable end orientation resulting from alternate slip on the [2ii0] and [1120] directions. This is analogous to the duplex slip process in face-centered cubic metals." Unpredictable Slip: In a number of crystals whose orientations were well within the operation of a single slip system, secondary slip occurred on planes not predicted by the criterion of maximum shear stress. Examples are shown in Fig. 3. In addition to

Jan 1, 1955

By Tasuku Fuwa, John Chipman, David H. Kirkwood

Fe-C-Si alloys in silica crucibles were held at 1600°C in a controlled atmosphere of CO and Co2 and the approach to equilibrium was obsertsed. Results were not of sufficient precision to establish the activity and interaction coefficients. Observations 012 the equilibrium provided an average value for the standard free-energy change which differed by + 1.1 kcal from the earlier accepted value. The C-SL relation at other temperatures is calculated and shown graphically. IN the refining of steel in an acid-lined furnace, it is well known that, unlike in basic refining, a very significant amount of silicon may remain dissolved in the metal even when the carbon content approaches a final endpoint. Further, it is known that the residual silicon increases with increasing temperature. The quantitative relation between silicon and carbon can be calculated for equilibrium conditions from data already available on the Fe-C-O and the Fe-Si-O systems. Such equilibrium calculations could show us approximately the limitations within which the reaction would be expected to operate in practice. In the oxidation of a bath containing both carbon and silicon it is well known that at low temperatures silicon is preferentially oxidized first. It can be shown by calculation that at high temperatures carbon will be oxidized preferentially. It is the purpose of this paper to record direct observations on the Si-C relation by means of experiments carried out in an atmosphere of carbon monoxide for Fe-C-Si alloys contained in silica crucibles. When such a system is brought into equilibrium, at a fixed temperature, the composition of the liquid metal is governed by the following equations: Both K1 and K2 are known with a fair degree of accuracy, and may be calculated from the tabulated In general the percentage of CO2 is extremely small compared to that of CO and in the experiments to be described the partial pressure of the latter was generally only slightly below 1 atm. EXPERIMENTAL METHOD The induction furnace employed was the same as that described by Rist and chipman&apos; and by Fuwa and chipman.2 It was modified slightly in view of the change from alumina to silica crucibles. The small silica crucible was surrounded by a thin susceptor of molybdenum sheet which in turn rested inside a zirconia crucible. Since the zirconia was subject to breakage, it was supported inside an alumina crucible. The charge consisted of 30 to 35 g of electrolytic iron along with the required amounts of refined silicon and graphite to produce a melt of required composition. Purified carbon monoxide and carbon dioxide were passed into the furnace through carefully calibrated flow meters. Two separate and independent series of experiments were carried out. In Series I (D.H.K.) the melt was held in the furnace at 1600°C for periods of time up to 6 hr. Samples were taken at intervals in silica tubes and were analyzed for carbon and silicon. The results of the last one or two samples taken from each experiment and the direction in which equilibrium appeared to be approached are shown in Table I. In Series II (T.F.) the silica crucibles were of less satisfactory strength and the melts were held at 1600° C for periods of only 2 to 4 hr. In heats number 29 to 45 inclusive, the metal was cooled in the furnace and the ingot itself served as a sample for analysis. In heat 46 and all subsequent heats, samples were withdrawn in silica tubes at the termination of the heat, and these samples were analyzed. The results of all of these experiments in which equilibrium appeared to be approached are listed in Table II.

Jan 1, 1965

By Donald A. Corrigan, John Chipman

It is shown that the heat of solution of nitrogen in liquid-iron alloys is Proportional to the interaction coefficient. This proportionality forms the basis for a method of predicting nilrogen solubility at any temperature when the interaction coefficient is knoun at 1600°C ov when the solubility is known at some one temperature. A method for predicting the solubility of nitrogen in liquid steels, including alloy steels, was proposed some years ago by Langenberg.&apos; Since the data available at that time were restricted to temperatures of about 1600°C, his predictions were similarly restricted. More recently, Nelssonz devised an approximate method for estimating nitrogen solubilities at higher temperatures. It is the purpose of the present paper to present a method by which the solubility of nitrogen at any temperature within the steelmaking range may be predicted from the known interaction coefficients at 1600°C. Nitrogen in iron and in all of the alloys to be considered here is known to obey Sieverts&apos; Law; hence the activity of nitrogen in an alloy of fixed composition is proportional to its concentration, here expressed in weight percent. The activity of nitrogen is defined as equal to its weight percent in the binary Fe-N solution at any temperature. Its activity coefficient in any alloy is the comparison being made at equal values of T and PN2. In all alloys the activity coefficient changes with composition, log fN being a linear function of the percent of alloying element at low concentrations. In the following calculations the alloy compositions are restricted to those in which this linear relation is exhibited. For most systems this is a fairly wide range, for example up to 5 pct V and to 10 pct Cr or Ni. For this composition range. complex alloy is the same as that in the Fe-N-j ternary solution. Langenberg&apos;s method of prediction was based on Eq. [3], the values of log fN for various additions being taken from a graph. Instead of using the simple addition indicated in Eq. [3], he used a more complex method suggested for Fe-S-j alloys by Morris and Buehl.3 For the composition ranges in which Eq. [2] is valid the two methods are equivalent. Nelson extended the prediction to other temperatures on the assumption that logfN is inversely proportional to absolute temperature. It may be shown that inverse proportionality would result if the partial molal entropy of nitrogen were unaffected by addition of the alloy element, an assumption which Nelson designated as a "regular" solution. It has been shown recently by the authors4 that this assumption is not a good approximation. The heat of solution of nitrogen (N2) in an alloy may be obtained if the solubility is known as a function of temperature. Measurements of this nature have been reported recently by Beer5 for Fe-Mn alloys, by Nelsson2 for Fe-C, by El Tayeb and parlee6 for Fe-V, and by Pehlke and Elliott7 for many alloys embracing a wide range of compositions. In connection with the work of the last named authors it is noted that their Fig. 22 gives the heat effect per half mole rather than per mole of N2. In using their data we have shifted some of their values slightly by using the best straight line in preference to their curve. Their data, supplemented by others from the literature, are summarized in Table I. In Fig. 1 the heat of solution of nitrogen is shown as a function of composition for the several alloy systems. The difference between the heat effect in the alloy. AH; and that in pure

Jan 1, 1965

By K. D. Jacob, W. L. Hill

Fluorine recovery in the United States has been restricted chiefly to manufacture of ordinary superphosphate and wet-process phosphoric acid. However, there is an expanding use of fluorine by industry in the form of hydrofluoric acid. Improved methods for recovering fluorine from phosphate rock would yield an adequate supply of fluosilicates and a substantial contribution to the hydrofluoric acid requirement. THE bulk of natural phosphates is comprised of calcium phosphates, which are usually apatites;&apos; calcium aluminum phosphates such as pseudowavel-1ite; and aluminum phosphates, which occur in extensive deposits, notably on Grand Connetable Island." Nearly all deposits of current commercial value are apatite, often with admixed material of other classes. In the trade coarsely crystalline material, mainly fluorapatite of igneous origin, moves as apatite, whereas the fine-grained material of sedimentary origin is marketed as phosphate rock. The latter classification includes the phosphate shales in western North America. Although several genetic varieties of phosphate rock are recognized, most known reserves are of marine origin. Calcium phosphate is concentrated from Florida land pebble and Florida hard rock deposits and from Tennessee brown rock deposits. Phosphate Rock as a Fluorine Carrier: More than two decades ago Reynolds and Jacob surveyed the fluorine content of commercial phosphate rock from various parts of the world. Later these samples were re-analyzed by a new and more reliable method of determining flourine. The revised results with interim additions of new samples, published a few years ago in a brief summary," are shown in Figs. 1-3. Through the points representing the respective varieties of rock medial straight lines are drawn. In some instances the lines are well defined by the points; in others, where scattering renders the position of the best line uncertain, the greater weight is given points near the end of the covered range. Wherever distinct varieties are not recognized among regional deposits the custom is to identify the sample with the geographical location of the deposit. Although all rock varieties cannot be classified with certainty, the plotted results exhibit three distinct types of rock in which the F to P2O5 ratio diminishes, remains sensibly constant, and increases, respectively, as the grade of rock increases. Existence of two types of Florida land pebble, Fig. 1, is supported by additional results recently supplied by a producer." Generally speaking, phosphate rock from continental deposits carries considerably more fluorine, and apatite and insular phosphates less, in proportion to the phosphorus content than is required by the formula for fluorapatite. Exceptions to this are apatite from Canada and certain samples of Florida waste-pond phosphate. The manner in which excess fluorine is held and the nature of the carbonate in carbonate apatite are discussed in recent articles. High-grade calcium phosphates with F to P2O5 ratios less than 0.05 have been found in Curacao, Christmas Island," Mexic,13 and elsewhere. The calcium aluminum phosphates and aluminum phosphates aften carry notable amounts of fluorine. The F to P2O, ratio for one sample of pseudowavel-lite concentrate was 0.05." Aluminum phosphate from Grand Connetable Island is very low in fluorine, whereas some aluminum phosphate minerals" carry as much fluorine as highly fluorinated phosphate rock. Fluorine in Domestic Phosphate: The curves shown in the figures permit interpolation of the F to P2O5 ratio corresponding to the midpoint of selected ranges in grade of any one of the several varieties of phosphate. Multiplication of the interpolated ratio by the mid-range grade (P2O5) yields a figure for the percentage of fluorine in this grade. Then, with the use of the mid-range grade, the amount of fluorine held in phosphate reserves can be estimated, see Table I. Accordingly, on Jan. 1, 1950, the fluorine complement of known domestic reserves exceeded 420,000,000 long tons of the element. A previous figure," deduced in 1940 by a simpler procedure

Jan 1, 1955

By J. J. Gilman

RECENT experiments have shown that the mar-tensite reaction in a standard tool steel is influenced by the history of the reacting austenite. The martensite reaction proceeds to a given extent at a higher temperature in austenite formed from an annealed spheroidal structure than it does in austenite formed from tempered martensite: that is to say, a prequench lowers the temperature range of the martensite reaction in this steel. Furthermore, a prequench alters the appearance of the martensite as compared to martensite formed from "virgin" austenite. The steel used for this work was a manganese nondeforming tool steel of the following composition: C, 0.85 pct; Mn, 1.43; Si, 0.23; Ni, 0.12; Cr, 0.59; and W, 0.59. A piece from a rolled bar was forged to Vz in. sq and annealed to a spheroidal structure. Disks 1/8 in. thick were used in the experiments. Several sets of the specimens were prepared and austenitized in lead at 1475°F. Three sets were held at 1475°F for 15 min, quenched in water, and immediately reheated to 1475°F. After this quench the three sets were held for 5 min, 30 min, and 3 hr, respectively, at 1475°F and then the individual specimens in each set were quenched in molten baths to 325", 300°, and 275ºF, respectively, and held for 15 sec. Immediately after the quenching treatments? the specimens were tempered at 600°F for 30 sec to darken the martensite and then were quenched in water. The holding times were short enough to avoid isothermal transformation. Three other sets of specimens were given the same final quenching treatments as the first three, but they were austenitized at 1475°F for 20 min, 35 min, and 3 hr and 15 min, respectively, without an intermediate water quench. The two individual specimens from each set were quenched together in order to eliminate quenching errors. Several experiments were run in this way but only the six sets referred to are described in detail because they all yielded essentially the same results. By means of the stated heat treatments the martensite reaction was investigated for: 1—austenite formed from an annealed structure, and 2— austenite formed from tempered martensite. The martensite reactions of the two types of austenite differed significantly. This is shown by Figs. 1 and 2. Comparison of the photographs on the left in Figs. 1 and 2 with those on the right shows that less martensite was formed by a quench to a given temperature from prequenched austenite than from austenite formed from an annealed structure, that is, the prequench suppressed the martensite reaction. The effect was observed for specimens austenitized 20 min, 35 min, and 3 hr and 15 min. A comparison of Figs. 1 and 2 shows that the martensite reactions in both sets of specimens occurred at lower temperatures with increased austenitization time. This was caused by the increased dissolution of residual carbides with time at 1475°F. However, the difference in amount of martensite formed in prequenched austenite as compared to virgin austenite was approximately the same for all three austenitization times. One further observation should be noted. The needles of the martensite formed from virgin austenite are somewhat longer on the average and show less of a tendency to cluster than those of martensite formed from prequenched austenite. This causes the martensite on the right in Figs. 1 and 2 to have a more acicular appearance than the martensite on the left. Since the sets of specimens used in this work were austenitized for identical total lengths of time and the effect of a prequench on the martensite reaction existed for specimens held at the austenitizing tem-

Jan 1, 1953

By Nicholas J. Grant, Olaf Troili, John Chipman

IN recent studies of the factors which affect the rate of desulphurization and its equilibrium, it became apparent that certain concurrent reactions were operative which had a significant effect on desulphurization. This is emphasized in the experiments of Hatch and Chipman1 and of Grant, Kalling, and Chipman&apos; by the slow approach to a final state of equilibrium which is in marked contrast to the initial rapid transfer of sulphur from metal to slag. Since the removal of sulphur is of such profound importance in iron and steelmaking, it appeared necessary to investigate the reactions responsible for this behavior. It is now known that the presence of iron oxide in the slag interferes seriously with the principal reaction of blast-furnace desulphurization: CaO (slag) +-S + C - CaS (slag) + CO [l] The interfering reaction is most simply expressed as: CaS (slag) + 0 = CaO (slag) +-S 121 and a small concentration of oxygen (or FeO) is sufficient to hold a considerable amount of sulphur in the metal. It has been shown by Grant, Kalling, and Chipman2 that the addition of MnO to blast-furnace slag slows the removal of sulphur from the metal. This effect overshadows the contribution of MnO to basicity and is ascribed to its oxidizing power. It will be shown in this paper that SiO, also has sufficient oxidizing power to interfere with blastfurnace desulphurization. This is, of course, only one of its several effects. Primarily it is an acid and therefore reduces the concentration of excess lime. But when silicon is reduced to the metal the oxygen to which it was previously bonded becomes in part available for reaction 2. The proof of this statement is found in the following experiments. Experimental Procedure and Results Utilizing the same procedure and apparatus described by Grant, Kalling, and Chipman&apos; five additional heats were made using slags IV and 11, the starting compositions of which were: slag IV—40 CaO, 10 MgO, 35 SiO,, 15 A1,0,; and slag 11—50 CaO, 10 MgO, 25 SiO,, 15 Al3O3. An important difference between these heats and those previously reported was that silicon to the extent of 1 to 4 pct was added to the present heats whereas the starting silicon content was formerly about 0.2 pct. Table I shows the slag and metal analyses for heats 82 to 87, and Table I1 shows the silicon addi- tions made to the charge. These additions are based on 400 g of metal and 400 g of slag. All heats had 1.65 400pct S charged before the cold slagadditions. The temperature was maintained at 1525°C. Rate of SiO, Reduction: Fig. 1 shows the silicon content of the metal in contact with slag IV at 1525°C as a function of time. Heat 70 from the work of Grant, afunctionKalling,of and Chipman is included as the lowest starting silicon. It will be noted that eeven with 4 pct Si in the starting metal, there is an increase in silicon content with time. Heat 84 is apparently approaching silicon equilibrium very slowly. Heats 70 and 82 with very much lower slowly.starting silicon show a more rapid initial rise in startingsilicon content but do not reach equilibrium during a long holding period. Fig. 2 shows 3 different initial silicon contents for Fig.2shows3differentheats 73 (from Grant, Kalling, and Chipman) 86 and 87, in contact with slag II, the most basic slag. Heat 73 is increasing in silicon with time, whereas heat 87 with an initial silicon content of 3.7 pct shows a decrease with time. Heat 86 shows a very close approach to equilibrium. The rate of transfer of silicon from slag to equilibrium.metal is very slow in all of those heats, even those which are initially far from equilibrium. ____

Jan 1, 1952

By Henry J. Sandri

The use of economic models for forecasting purposes is an inexact yet necessary tool for mineral decision making. One method not commonly used is cyclical analysis because of its "non-scientific approach". However, under certain circumstances a modified cyclical approach can provide useful insight to mining companies. The current paper discusses mineral modeling, the type of economic models and the use of cyclical forecasting for mining firms (not speculators) involved in precious metals.

Jan 1, 1984

By JAS. F. McCARTHY

THE present Hecla Co. is a Washington corporation; the Hecla Co. of Idaho was the old company. The older corporation owned two claims, the Hecla and the Katie May, and was incorporated for 500,000 shares of one dollar par value. The principal shareholders and officials of the older company were among the early mining men of the camp. Among the active officials were John A. Finch and A. B. Campbell. Among the directors and share- holders were Patrick Clark, J. R. Smith, Frank Upman, F. J, Kipp, Chas. Kipp, B. A. Kipp and Carl Landsee. F. J. Kipp and Carl Landsee are now directors of the Company. All of the others mentioned have died, but the surviving members of their families retain their ownership in the Company&apos;s shareholders. B. A. ,Kipp, who recently died, was the largest shareholder at the time of incorporation and Patrick Clark was the second largest shareholder. B. A. Kipp is a brother &apos;of F. J. Kipp, director of the Company.

Jan 1, 1924

Jan 1, 1927