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By M. K. Barnett

Engineering research consists, broadly speaking, in the investigation of the effect of the variations in a number of factors on some property of a product or characteristic of a process. The unambiguous description of the product or process requires that the property or characteristic be expressible in quantitative terms. For the purpose of practical control, it is likewise desirable that the independently variable factors governing the product or process be quantities, although this ideal goal is not always attained. Maximum efficiency—i.e., the attain- ment of the maximum amount of reliable, useful information relating to the influence of, the factors on the property of the product or characteristic of the process, for the least expense—is an important requirement for the satisfactory operation of a research organization. Obviously, a necessary condition for the attainment of maximum efficiency is an adequate knowledge of the specialized field in which the experimental research lies. While necessary, this condition is not sufficient. Proper attention must also be given to the general principles of experimental design together with the modern methods for the analysis and evaluation of experimental data. The Present discussion is confined to a single design, the so-called "factorial" design. This design is of special interest in that it attains its goal, maximum efficiency, by directly departing from the

Jan 1, 1948

By Alexander Field

IN THE light of the experimental data on equilibrium for the reaction C + FeO = Fe + CO in molten steel recently obtained by Kinzel and I Egan,1 it is necessary to revise current theories regarding the nature of equilibrium between carbon and FeO in the basic open-hearth furnace. According to the measurements of these investigators the equilibrium constant m for the above reaction for a pressure of dissolved CO equal to 1 atm. is equal to 0.0005 at 1550° C., when concentrations of carbon and. FeO are expressed in percentages by weight. Their work also shows that, with the pressure of CO fixed at 1 atm., not only is the product of carbon and FeO constant, but carbon and FeO are each independently constant-a circumstance which might have been predicted from theoretical considerations. At 1550° C., carbon is constant at about 0.025 per cent. and FeO at about 0.020 per cent., with the pressure of dissolved -CO equal to 1 atm., the product of these two constants being equal to the originally mentioned constant of 0.0005. Available data on the dissolved FeO content of samples taken from the metal bath at practical slag-metal equilibrium prove that this FeO content is determined solely by temperature and the effective FeO content of the slag. The distribution constant r at 1550° C., as determined by Herty, Gaines, Larsen, Simkins, Geruso and Watkins2 is equal to 0.0086. A slag would have to contain 0.020/0.0086 = 2.3 per cent. effective FeO or less in order to prevent the metal from containing more dissolved FeO than that required for equilibrium with CO at 1 atm. pressure. Such low percentages of FeO are never found in basic open-hearth slags at the completion of a heat when rate of carbon drop has become practi-

Jan 1, 1930

By Jean Howard

RECENT attempts to produce secondary recrystalli-zation in high-purity iron have given conflicting results. Coulomb and Lacombe1'2 did not find it but Dunn and Walter3,4 did. The latter workers have stated that (100) [001] and/or (110) [001] orientations develop depending on the oxygen content of the annealing atmosphere. This Technical Note records results which are in agreement with Dunn and Walter in so far as it shows that secondary recrystallization can be produced in high-purity iron, but does not confirm that both types of orientation are obtainable. Similar observations have been made on chromium-iron and molybdenum-iron, although when this technique is used on 3 1/4 pct Si-Fe, both types are obtained as in the work of Dunn and alter.' Pure iron strip was cold-rolled from sintered compacts prepared from Carbonyl Iron Powder-Grade MCP of the International Nickel Co. (Mond) Ltd. The powder contains about 0.5 pct 0, 0.01 pct C, 0.004 pct N, (0.002 pct S, $0.005 pct Mg and Si, and 0.4 pct Ni—that is, it is substantially free from metallic impurities other than nickel, which is thought to be unimportant in the present work. The iron powder was (a) pressed at 25 tons per sq in. into blocks measuring 3 by 1 by 0.3 in., (b) deoxidized in hydrogen (dewpoint -60°C) by heating first at 350°C and then at 600° C until the dewpoint returned to -60°C at each temperature and (c) sintered in hydrogen (dewpoint -40°C) at 1350°C for 24 hr. (when dewpoint is referred to in this Note, it is the value as measured on the exit side of the furnace). The sintered compacts were cold-rolled to 1/8 in., annealed in hydrogen (dewpoint -60°C) at 1050°C for 12 hr and cold-rolled to 0.004, 0.002, and 0.001 in. with inter-anneals at 900°C for 5 hr and a final reduction of 50 pct. Final annealing of strip between alumina or silica plates at 875" to 900°C in hydrogen with dewpoints of -20°, -55" and -80°C produced secondary grains with the (100) in the rolling plane; the extent of secondary recrystallization was greatest when the dewpoint was -55°C. Annealing in a vacuum of 2 x 10"5 mm Hg at the same temperature produced no secondary recrystallization at all. With strip thicker than 0.002 in. very few secondary crystals developed whatever the conditions of annealing. Using a processing schedule somewhat similar to that described above, secondary recrystallization was produced in two bcc alloys of iron, viz. 80 pct Fe + 20 pct Cr and 96 pct Fe + 4 pct Mo. The former was reduced to final thicknesses of 0.001 to 0.004 in. and the latter to final thicknesses of 0.001 to 0.016 in. With the chromium-iron, a final anneal at 1250°C (found to be the most effective temperature for developing secondary crystals in the 0.004-in material) with a dewpoint of -25°C produced a greater degree of secondary recrystallization than with dewpoints of -50°C or -20°C. Secondary crystals developed in strips of all thicknesses from 0.001 to 0.004 in. Final annealing in vacuum produced no secondary crystals at all. For the molybdenum-iron a temperature of 1200°C was most effective. It was found that a dewpoint of -50°C during the final anneal gave better results than a dewpoint of -25 "C on the 0.008 in. material. Final annealing in vacuum gave slightly worse results than annealing in hydrogen with a dew-point of -50°C. Secondary crystals were developed in strips of all thicknesses up to 0.008 in. The experiments show that the extent of secondary recrystallization is a maximum for certain critical values of oxygen content of furnace atmosphere and annealing temperature, and that these values are different for different alloys. The thinner the material, the less critical these values are. The general conclusions are that secondary recrystallization can be obtained in high-purity iron, chromium-iron, and molybdenum-iron, using a processing schedule similar to that which will cause the phenomenon to take place in high purity 3 1/4 pct Si-Fe. Unlike the silicon-iron, however, only the (100) (0011-- orientation has been produced in these alloys, irrespective of the temperature of final annealing and the oxygen content of the furnace atmosphere. The information used in this Note is published by permission of the Engineer-in-Chief of the British Post Office.

Jan 1, 1962

By T. Smales, P. L. Wright, K. Barron

The results of field measurements using an air injection technique to investigate the integrity of three pillars in the Mclntyre Mines Ltd. 114 seam at Crande Cache, Alberta, are reported. These pillars are shown to be stable and an estimate is made of the strength of these pillars. Using these results, together with Hustrulid's pillar strength formulae, a general pillar strength equation for the 114 seam is developed. This equation takes into account the probability of failure that may be deemed tolerable within the design requirements. The variation of the minimum pillar dimensions with depth below surface for uniform pillar layouts is then examined for a range of tolerable failure probabilities. A general equation of the form B = 2.60 +B Z relates the minimum pillar design width, B metres, with the overburden depth, Z metres, where B is a parameter related to the tolerable failure probability. This equation only applies for 3.05m high pillars with 6.lm wide entries. Finally, the question of what failure probability is tolerable within the design of mine pillars is discussed. This will depend on the support role required of that pillar and the anticipated period over which the pillar must perform that role. Five categories of coal mine pillars are defined, each with a somewhat different role to perform. Tentative design criteria in the form of "tolerable probabilities of failure" are suggested for four of these five categories of pillar. The fifth category of pillar has no reliable support function to perform and support must be obtained by other means.

Jan 1, 1983

By C. G. Durdaller, W. H. Robinson, G. M. Pound

The nucleation rate of the a (pay) to 0 (white) tin transformation was measured as a function of temperature and a tin particle size using an X-ray diffraction technique. The powder specimens of a tin were essentially monodisperse and the small dinzension of the particles of these specimens was varied from 13 to 75 p. Several types of nucleation sites of differing potency were fbund to be operative in the nucleation process, but it could not be determined whether these sites were on the free surface of the tin particles or within the volume. Assuming that they were on the free surface, the average density of the most potent sites was calculated to be 2.5 to 5.3 x 10' sites per sq cnz through the application of a Poisson distribztion finction to the isothermal data. Analysis of the temperature dependence' of the rate constmts at a given fraction transformed suggests that the active sites are regions of higher free energy and not catalytic interfaces. Appreciable induction periods were observed at the lower temperatures of transformation. Experimental studies1 of solid-solid phase transformations have led to the belief that the new phase nucleates at structural imperfections. The purpose of the present work was to learn more about the mechanism of nucleation in solids and the nature of the singularities at which nucleation occurs. In this investigation nucleation rates in the isothermal transformation of gray to white tin were measured by an X-ray diffraction technique using essentially monodisperse powders of gray tin. This particular phase transformation was chosen for study because it presented fewer experimental difficulties than most others. The experimental temperature-control problems were minimal because the two phases coexist in equilibrium at 13.3"C, and measurable transformation rates occur at temperatures only slightly above room temperature. The growth rate of the P phase into the a2 is sufficiently fast to make the measured transformation rate equivalent to the nucleation rate, provided that the particle size of the samples is small enough; for the experimental temperatures used in this study, the particle diameter must be less than 100 p. EXPERIMENTAL TECHNIQUE The P tin used in this study was obtained from Capper Pass and Son Ltd., North Ferriby, Yorkshire, England, and was of 99.999 pct purity. It was transformedS to the a phase and ground into a fine powder in an agate mortar. This powder was separated by a Roller air classifier into seven fractions whose dimensions, as determined by microscopic measurement of many thousands of particles, are given in Table I and whose distribution of size within each fraction is given in Figs. 1 and 2. The shape of the particles was roughly that of an oblate spheroid,

Jan 1, 1964

By Ichiro Ito

At present, in Japan, the application of in-place leaching technique to the mined-out stopes has been carried out at two copper mines in a comparatively large scale. These mines are the Kosaka mine and the Tsuchihata mine, both are situated in the north-east district of Japan. At first, the author would like to tell about the in-place leaching operations and their results at these two mines. Then, the problems involved in the application of in-place leaching technique to the Japanese metal mines and the possibility of the future development of this technique in Japan are referred, too. Next, as to the research works, the author would like to explain briefly about some of the important results obtained in the recent studies on in-place leaching as well as on bacterial leaching in Japan.

Jan 1, 1976

By E. J. Dulis, R. M. Fisher, K. G. Carroll

IT is well known that ferritic steels containing more than 15 pct Cr when subjected to temperatures in the range of 700" to 1000°F exhibit increasing hardness and decreasing ductility. The phenomenon has been widely termed the "885 °F embrittlement," after the temperature of most marked effect.'.' In view of the excellent review articles available in the literature3-6 only a brief account of experimentally established facts need be given here. The extent of changes in physical characteristics during embrittlement depends on chromium concentration and time at temperature, higher alloy content and longer time both promoting more rapid and extensive changes. In a 27 pct Cr steel, changes in impact strength and in angle of fracture in bending can be detected after only a 1 hr exposure at 885°F; after 50 hr this steel becomes quite brittle. Hardness increases slowly with time during thousands of hours exposure and may attain a maximum hardness number twice as large as that of the unexposed steel. Microstructural changes accompanying embrittlement have been described as an initial widening of grain boundaries followed by eventual darkening of ferrite grains. Embrittled steels etch more readily, e.g., the weight loss of a 27 pct Cr steel in acid solution may occur at a rate one hundred fold greater following exposure at 885 OF. Marked changes which accompany embrittlement have been observed in electrical resistivity, specific gravity, and magnetic coercive force. Changes in physical properties may be readily removed by heating at temperatures above the embrittling range, such as a treatment at 1100°F for 1 hr. It has frequently been noted that the 885 °F embrittlement suggests precipitation on a submicro-scopic scale of a chromium-rich constituent, the nature of which has not been revealed by X-ray diffraction. Progressive broadening of the body-centered cubic diffraction lines during embrittlement has been observed," and recent observations by Lena and Hawkes' upon single crystals have shown early asterism in X-ray photographs, disappearing within an hour at 900 °F. Many workers have ascribed8-13 the phenomenon to a precipitation of a phase (FeCr), which is known to cause embrittling effects at temperatures much higher than 885°F. Two general observations, however. suggest that a precipitation cannot be responsible for the 885°F phenomenon: 1—prior cold work greatly enhances a formation, whereas it scarcely affects the 885 °F embrittlement, and 2—the presence of an alloying element such as nickel or manganese may have an effect on the 885 °F embrittlement which is opposed to its effect upon a formation. The slight enhancement of a formation and 885°F embrittlement observed in the presence of elements with strong carbide and nitride forming tendencies' is probably a consequence of lessened chromium depletion of the matrix. The bar graph in Fig. 1 shows a typical example, taken from two 27 pct Cr steels used in this work, of the hardness after exposure for 10,000 hr at 900°, 1050°, and 1200°F. Steel A (0.03 pct C, 3.13 pct Mn) showed marked hardening at 900" and 1200°F, whereas steel B (0.12 pct C, 0.63 pct Mn) exhibited only the 900°F hardening. The cr phase was found in steel A at the higher temperatures but not in steel B. Presumably a formation is enhanced by the low-carbon and high-manganese concentrations in A," Thus there are two distinctly different hardening phenomena present which cannot both be ascribed to v precipitation without invoking a transition phase possessing remarkable properties. Materials A number of chromium steels exposed for long periods (5000 to 34,000 hr) at 900°F, as well as unexposed samples of one of the steels, were available for this investigation. Table I gives the chemical compositions and aging treatments of these steels. In addition to these steels exposed in the elevated temperature test furnaces of the National Tube Division, a number of high-chromium steels were heated for short periods in small laboratory air furnaces and lead baths. Supplementing these commercial steels, a sample of high-purity (0.018 pct C, 0.002 pct N) 28 pct Cr iron, exposed 1000 hr at 887°F. was furnished by the Union Carbide and Carbon Corp. In addition, an alloy of iron and chromium of high purity containing 46 pct Cr was used. This

Jan 1, 1954

By Oswald J. Heinrich

During the last twenty years much has been done to investigate and define the Mesozoic formatibn of the United States along the Atlantic States, as well as in' the Territories. The investigations of Professors Hitchcock, Emmons, Hayden, H. D. Rogers, and those now in progress in connection with the geologicd surveys of Penn-

Jan 1, 1879

By Jaakko Kajamaa

Neutron diffraction was applied to determine sheet textures by the transmission method. Cold-rolled and recrystallized copper sheets were investigated. The amount of cube texture was determined for three compositions, in which the phosphorus content was, respectively, 0, 0.005, and 0.03 wt pct. The heat treatment was in every case 8 sec at 650°C. In the two latter cases the cube texture was prevented. In addition a comparison with the X-ray diffraction transmission method was made with the 96 pct cold-rolled copper sheet. Outer parts of both (111) pole figures can be considered to be rather identical. This is seen from the fact that the intensity ratio ITD/120" was 0.45 for neutron diffraction and 0.40 for X-ray diffraction. Differences between the methods were discussed in detail. Features peculiar to neutron and X-ray diffraction in texture studies were listed and compared. In this work neutron diffraction was applied to determine sheet textures. Specifically, it was desired to ascertain whether this method can be used to reveal differences when compared to other methods. In addition, the amount of the cube texture in copper sheets was determined as a function of phosphorus content. Previous applications of neutron diffraction to texture problems include the following: nickel wires,' wire of some bcc metals,' and uranium bars.3 In the neutron diffraction technique the greatest difference is in the sample—its method of production and its volume. A sample needs no treatment and its volume is roughly 105 times larger than the volume of an X-ray diffraction sample. The cold-rolled sheet was investigated both by neutron diffraction and by X-ray diffraction, because it is expected that, due to large number of defects, possible differences in the results of the two methods would be revealed. It is a well-known fact that X-ray lines show broadening when cold-worked. Analysis has shown that this is based chiefly on small crystalline size, micro-stresses, and/or faults.4'5 Neutrons are sensitive to the above-mentioned disturbing factors as well, but circumstances in diffraction are different from the X-ray case. Because the sample represents a larger volume, the result is an average over that volume. In addition, it can be assumed that the sample has preserved its original structure, because it needs no special preparation. The particular limitation of neutrons is the relatively low neutron intensity available from nuclear reactors. This decreases the resolution as compared to the X-ray diffraction methods. Furthermore, absorption mainly reduces diffracted X-ray intensity, while multiple scattering effects, i.e., secondary extinction, disturb neutron diffraction. SO neutrons and X-rays behave in a different way when interacting with matter. As in other structural investigations, one can utilize this difference in texture studies as well. One cold-rolled and three recrystallization textures in copper sheets were investigated by neutron diffraction. The samples were produced at the Outokumpu copper factory to the specifications shown in Table I. The paper is divided into five parts. The first deals with the theory of the measurement. In the second, experimental procedures are described. Results are presented in the third part. Both cold-rolled and re-crystallized samples are studied. Discussion is in the fourth part, and finally in the fifth part some conclusions are drawn. 1) THEORETICAL CONSIDERATIONS Properties peculiar to neutron diffraction are the following: a) the scattering length varies greatly between one element and another; b) many of the elements do not absorb neutrons appreciably. In this connection it is of primary interest to know the interaction of neutrons with lattice imperfections. As with X-rays this problem leads to diffraction analysis of deformed and recrystallized metals. From the physical point of view the main difference is that neutrons are scattered by nuclei (magnetic scattering is not considered here), whereas X-rays are scattered by electrons. The features peculiar to neutron and X-ray diffraction methods in texture studies are listed in Table 11. Pole figures are an important tool in performing structural analysis of deformed or recrystallized metal. Present texture research technology requires pole figures which are as precise as possible. The choice between these two methods depends on the technical information which is required. The X-ray diffraction transmission technique may give results which are not necessarily representative of the average physical state of the sample. Although foil samples normally contain enough crystallites for diffraction, they may not necessarily represent the whole structure. An example of this problem is the frequently observed difference between the "surface" and the "inside" texture of a sample. The production of foil samples may disturb the original structure of the parent material. The selection and orientation of the foil from the sample is quite arbitrary. Normally, a highly deformed piece of metal has several texture components. Different components are deformed in a slightly different manner. This is a re-

Jan 1, 1969

By Pablo Hadzeriga

Great Salt Lake brine was subjected, in laboratory scale, to conditions simulating solar evaporation. Solid phases and the variation in composition of the liquid phase throughout the potassium salts crystallization zone are presented. These experimental results are discussed and compare with stable equilibrium data of the quinary system Cl-, SO4, Na+, K+, Mg + + and H2O. The Great Salt Lake brine in Utah is a vast reserve of several potential chemicals which has attracted much attention in the recent past. From the standpoint of an ore reserve, it may be said that the lake contains a low grade ore which has to be concentrated by evaporation of water. Because of the fairly favorable weather conditions in the Great Salt Lake area, it seems reasonable to consider solar evaporation as an economical means of concentration. From the view of phase chemistry, the main constituents of Great Salt Lake brine make it belong to the five component system: C1-, SO4=, Na+, K+, Mg++ and H2O. Because of their low concentration, the presence of other elements may be regarded as having little effect on the equilibrium of the five main components. Equilibrium data for the quinary system of our interest has been available for many years. Using these data, it is possible to calculate how the brine of the lake will concentrate when subjected to solar evaporation. In practicing solar evaporation, the weather factor and supersaturation conditions cannot be ignored, but their introduction into calculations using equilibrium diagrams is almost an impossible task. With the experimental work presented in this paper, an attempt is made to compare the stable equilibrium data of the quinary system as applied to the case of the Great Salt Lake brine and the dynamic equilibrium when that brine is subjected to continuous solar evaporation. Sea water brine belongs to this quinary system when only the major constituents are considered. The study of this system has been carried on since the last decades of the nineteenth century. The reason for these intensive studies was to give a geological explanation to the underground potash deposits. AS a result, many theories were presented trying to relate the equilibrium data with the geological formation, paragenesis and metamorphism of these deposits. Two main approaches were followed for the equilibrium studies of this quinary system. One of them, and the best known to us, was the school started in Germany in the last century by J. H. Van't Hoff. The other one, which started about the same time, was the school of N. S. Kurnakov in Russia. Both approaches were different and as a consequence generated opposite theories about the geological formation of potash deposits. The Van't Hoff school studied the quinary system of sea water under careful laboratory control, resulting in stable phase diagrams. During these studies, Van't Hoff recognized the difficulties in crystallizing some double salts.' ". . . . we unexpectedly found that some compounds whose formation in the solutions under investigation was possible at 25°C, nevertheless totally failed to put in an appearance. These, not to mention the calcium salts, were leonite, MgSO4 . K2SO4 4 H2O; kainite, KC1-MgSO4 . 3 H2O; and kieserite, MgSO4 .H2O. Even exceedingly slow crystallization with the addition of the compounds themselves did not remove the condition of supersaturation in the case of these bodies." However, those salts (leonite, kainite, and kieserite) were included in the stable phase diagram at 25°C as shown in Fig. 1 using D'Ans data.3 The figure also shows the sequence of crystallization of the Great Salt Lake brine according to the stable diagram. In later studies by the Van't Hoff school, especially by D'Ans,3 Karsten,4 Autenrieth,5,6 attention

Jan 1, 1968

By C. B. Manula, R. Venkataramani, T. V. Falkie

A linear programming model has been developed to solve a production planning problem for a multi-plant stone operation serving several customers. The factors considered are production capacities, inventory restrictions, demand requirements, and available stone reserves. The objective function to be optimized is the total annual net returns from the quarry operations. For the purposes of model testing, annual stone sales from each plant were divided monthwise, productwise, and assigned to a market. The concept of assigning demands to market sectors and not to any particular plant creates the self-correcting interplay between the plants and the markets. Along with the inventory restrictions, and ending inventory requirements, this interaction enables the model to minimize the external diseconomics. The model was tested against an operating prototype and a number of alternative problems were also considered. Finally, the basic linear programming model has been enlarged by the addition of another dimension and the problem has been derived in a decomposition format.

Jan 1, 1972

By R. Schuhmann, A. M. Gaudin, J. Dasher

Occurrrences of South African uranium have been known qualitatively for over twenty years, but no account was taken of them because of their low grade. In 1945, known uranium deposits were few, but their grades were 20 to 100 times higher than South African ores. Viewed in this light, the exploitation of South Africa's uranium is revolutionary indeed. Development of various analytical procedures capable of dealing with the needs of the project accounted for one-half of the cost and included: a) simple and automatic radiometric analytical procedures, b) sampling procedures appropriate to prevent sample contamination, c) procedures for sample and record-storing to accommodate many thousands of analyses per month, d) chemical methods giving high accuracy analyses for high grade samples not at radioactive equilibrium, and e) development of rapid procedures having moderate accuracy for low grade samples i.e., mill tailings and barren liquors. This task is continuing today with major improvements coming from time to time.

Aug 1, 1956

By J. L. Rodda

A large amount of time has been devoted to the microscopical study of the copper-zinc alloys, emphasis naturally being placed upon the commercially important alloys of the system. Suitable methods are available for microscopically recognizing the two phases richest in copper, but none appear to have been developed for the positive identification of the other phases. This is, however, accomplished, for the phases normally encountered, by an electrolytic method described in the following pages. Five phases of the copper-zinc diagram (Fig. I) are considered for the purpose of this paper: the solid solution of zinc in copper, alpha (a); the intermediate phases, beta (ß), gamma (?), and epsilon (e); and the solid solution of copper in zinc, eta (11). Beta prime is not considered a separate

Jan 1, 1937

By W. F. Chiao

Ultrasonic attenuation, a, measurements in the frequency range of 5 to 55 mc per sec have been studied to determine their quantitative relationship with the following three variables of mixed microstructures in steels: 1) the volume percent, XF, of polygonal fer-rite in mixed structures of martensite and polygonal ferrite in Fe-Mo-B alloys: 2) volume percent, XA, of retained austenite plus martensite aggregates in high-carbon steel; and 3) substructural differences between 100 pct bainitic ferrite structures formed at various temperatures. The quantitative relationship obtained in the first two conditions by plotting a us the known structural parameters can be expressed, respectively, as: where al, a 2 and C1, Cz are constants. In the third condition the nature of the attenuation depends on the state of dislocations generated at the transformation temperatures and also on the alloy composition. From these measured results, the mechanism of ultrasonic attenuation caused by these mixed microstructures can also be studied. MUCH interest has recently been shown in the application of ultrasonic attenuation and wave velocity measurements to the study of the microstructural characteristics of steels. The general aims of most of the investigations in this field can be grouped into two categories: one is to study the mechanisms of ultrasonic losses caused by the characteristic phases in the microstructure of steel,''' and the other is to develop nondestructive test methods and applications for quality control.~' 4 Apparently no work has been done on the evaluation of ultrasonic attenuation meas -urements as a means of quantitative determination of a given phase in the microstructure of a steel. It is well-established that the decomposition of austenite results in four main microstructural constituents—polygonal ferrite, pearlite, bainite, and martensite—and that each phase has different mechanical properties. Thus, when a steel consists of mixed microstructures, the mechanical properties can often be related to a quantitative measure of the volume percent of each phase present. This study relates ultrasonic attenuation measurements to: 1) the volume percent of polygonal ferrite in mixtures of martensite and polygonal ferrite in Fe-Mo-B alloys; 2) the substructural differences between 100 pct bainitic ferrite structures formed at various temperatures; and 3) the vol- ume percent of austenite in austenite plus martensite aggregates in a high-carbon steel. The choice of the specimen materials was based on the laboratory stocks which were suitable to produce the required mixed microstructures for this study. EXPERIMENTAL PROCEDURES Materials and Heat Treatment. Polygonal Ferrite Plus Martensite Structures. This mixture of phases was produced in a vacuum-melted Fe-Mo-B alloy. The alloy was hammer-forged at 1900" ~ to a -f-in.-sq bar. By isothermally heat treating the alloy at 1300° F for various times and then water quenching, variations in the amount of polygonal (or proeutectoid) ferrite can be controlled in a microstructure in which the balance of the material is martensite. In the present work, four different times of isothermal transformation were adopted; after heat treatment, the four specimens were machined for ultrasonic measurements. The compositions, heat treatments, and dimensions of the four specimens are listed in Table I. 100 pct Bainite Structures Formed at Different Temperatures. It has been well-established by Irvine et al.= that the presence of molybdenum and boron in ferrous alloys can retard the formation of polygonal proeutectoid ferrite and expose the bainitic transformation bay, so that a more acicular or bainitic ferrite can be obtained over a wide range of cooling rates. Their investigation6 also showed that the mechanical properties of fully bainitic steels are usually closely dependent on the substructural characteristics of the steels. For studying the substructural characteristics in completely bainitic structures, six Fe-Ni-Mo alloys, of which five were free from carbon addition and one with 0.055 pct C addition, were selected so that a wide range of hardness values for 100 pct bainitic ferrite structures could be produced by normalizing at 1900" F followed by air cooling. The different bainitic transformation temperatures were recorded during air cooling. All of the alloys were vacuum-melted and then forged at 1900" F to square bars. Data on the six specimens of these structure series are summarized in Table 11. Austenite Plus Martensite Structures. The high-carbon steel used to study austenite plus martensite structures was vacuum-melted and then forged into Q-in.-sq bar. The series of mixed structures of austenite plus martensite was produced by quenching the specimens from the austenitizing temperature to room temperature and then refrigerating them at various temperatures within the range of martensite transformation to produce different amounts of retained austenite. Data on the four specimens of this series are listed in Table 111. Quantitative Analysis of the Microstructures. The microstructures containing martensite plus polygonal ferrite were analyzed by the point-counting technique.

Jan 1, 1969

By Arnulf Muan, D. P. Masse

PHASE relations in the system CoO-SiO2 have been determined as a basis for further investigations of thermodynamic properties of olivine solid solutions involving Co2SiO4 as a component. Previous data on the system CoO-SiO2 are incomplete or uncertain. Biltz and Lemke1 determined the melting point of cobalt orthosilicate as 1345°C , but Asanti and Kohlmeyer2 have later found a considerably higher temperature, 1420°C. The latter authors also studied melting relations of one mixture on the CO side and two mixtures on the SiO2 side of the orthosilicate composition and sketched a tentative phase diagram for a limited composition range of the system. However, no phase identification was carried out, and the authors left unanswered the question of the possible existence of a stable meta-silicate phase. Greig3 showed that a 90 wt pct SiO2-10 wt pct Co mixture at 1725°C consists of two immiscible liquid phases. The quenching technique was used in the present investigation. Mixtures of high-purity cobalt oxide ("Fisher Certified") and dehydrated silicic acid ("Baker Analyzed") were equilibrated in air atmosphere. The samples were then quenched to room temperature and the phases present were identified by microscopic and X-ray examination. The samples were kept in small envelopes made from thin (0.0004 in.) platinum foil. Thermodynamic data which have become available recently for Pt-Co alloys4 were used to check that the losses of COO from the oxide samples by alloying of cobalt with platinum in the present investigation were too small to change significantly the compositions of the oxide material during the equilibration. A vertical tube furnace with an 80 pct Pt 20 pct Rh resistance winding was used in runs up to 1510°C. Temperatures in these runs were measured with a Pt vs 90 pct Pt 10 pct Rh thermocouple calibrated against the melting point of diopside (CaMgSi2O6, 1391.5?C). The given temperatures as measured by this technique are estimated to be accurate to *5°C. Quench runs at temperatures above 1650°C were made with a modified Roberts and Morey5 strip furnace, using strip resistors composed of a 60 pct Pt-40 pct Rh alloy. Temperatures were measured with an optical pyrometer which was calibrated against the liquidus temperature of a mixture composed of 10 wt pct CaO, 90 wt pct SiO2 (1707°C). The temperatures measured with this technique have an estimated accuracy of +15°C. The results are shown graphically in Fig. 1. Only one intermediate phase, the orthosilicate Co2SiO4 with olivine-type structure, is stable in addition to the end members cobalt oxide and silica. The melting point of the orthosilicate was found to be 1415" ± 5°C. The metastilicate CoSiO3 is not stable at the temperatures of the present investigation. The two eutectic points in the system CoO-SiO2 where COO plus olivine, and olivine plus silica, coexist with liquid were found to be 72 wt pct COO and 1407°C and 63 wt pct COO and 1381°C, respectively. The melting point of cobalt oxide in air was taken as 1745?C, based on the previous data of Aukrust and Muan.6 Within limits of error (+ 5?C), identical eutectic temperatures to those determined in air were found when two representative mixtures were equilibrated at 1 atm O2 pressure and in an atmosphere of 84 vol pct CO2, 16 vol pct H2. This suggests that changes in oxidation state of cobalt in the condensed phases are not significant as far as their effect on the phase relations are concerned. This inference was substantiated by failure to detect7 any "excess oxygen" (i.e., oxygen in excess of that contained in Co2SiO4) in a sample of orthosilicate composition equilibrated in air 10°C above the liquidus temperature and subsequently quenched to room temperature. This work was carried out as part of a research program sponsored by the U.S. Atomic Energy Commission under Contract No. AT(30-1)-2781.

Jan 1, 1965

By Donald C. Barton

OF the four papers that comprise this Technical Publication, three are case histories of individual geophysical prospects, subsequently tested by drilling. The bibliography of Dr. Barton's published scientific paperst includes investigations in physiography and surface geological mapping, as well as his geophysical papers, and from this list it is to be observed that he early recognized the place of different types of geophysical prospecting methods in the search for geological structures of economic importance. Moreover, his viewpoint was not merely that the structures should be found, but that the geophysical data should be examined quantitatively to determine the geometry of the structures. In other words, that although these data are insufficient to deduce a unique form for the structure that caused the effects measured in the data, the engineering computations should be carried out to give as much of a definite configuration to the structure as the data permitted, in order that the testing of the structures could be conducted in the most economical manner and with the idea that the experience so gained could be later incorporated in the study of structures subsequently found. Dr. Barton continually emphasized the quantitative use of geophysical observations, whereas at the time that he began his specialization in geophysics it was considered sufficient to use observations only qualitatively. He, more than any one else, was responsible for the first volume on geophysical prospecting issued by the Institute in 1929, and his three articles in that volume stressed the quantitative use of geophysical prospecting. The fourth article in this present Technical Publication is a further contribution to this branch of geophysical interpretation, and is a supplement to the paper in the 1929 volume, "Calculations in the Interpretation of Observations with the Eötvös Torsion Balance." From the successful demonstration by Dr. Barton of the usefulness of quan-

Jan 1, 1946

By Donald C. Barton

OF the four papers that comprise this Technical Publication, three are case histories of individual geophysical prospects, subsequently tested by drilling. The bibliography of Dr. Barton's published scientific paperst includes investigations in physiography and surface geological mapping, as well as his geophysical papers, and from this list it is to be observed that he early recognized the place of different types of geophysical prospecting methods in the search for geological structures of economic importance. Moreover, his viewpoint was not merely that the structures should be found, but that the geophysical data should be examined quantitatively to determine the geometry of the structures. In other words, that although these data are insufficient to deduce a unique form for the structure that caused the effects measured in the data, the engineering computations should be carried out to give as much of a definite configuration to the structure as the data permitted, in order that the testing of the structures could be conducted in the most economical manner and with the idea that the experience so gained could be later incorporated in the study of structures subsequently found. Dr. Barton continually emphasized the quantitative use of geophysical observations, whereas at the time that he began his specialization in geophysics it was considered sufficient to use observations only qualitatively. He, more than any one else, was responsible for the first volume on geophysical prospecting issued by the Institute in 1929, and his three articles in that volume stressed the quantitative use of geophysical prospecting. The fourth article in this present Technical Publication is a further contribution to this branch of geophysical interpretation, and is a supplement to the paper in the 1929 volume, "Calculations in the Interpretation of Observations with the Eötvös Torsion Balance." From the successful demonstration by Dr. Barton of the usefulness of quan-

Jan 1, 1946

By J. F. Kemp

IN submitting an additional contribution to the discussion on ore-deposits in the recent volumes of the Transactions, it is my desire to adhere closely to matters of material importance as affecting the actual processes. Judging from the discussion by Professor Van Hise, and from one or two reviews or other articles by associates of his in geological work, the impression seems to prevail that, in so far as my paper* referred to ,his masterly essay,†I was guilty of misconceptions regarding both the part attributed by him in it to the igneous rocks and the ubiquitous presence of the ground-water. I should regret extremely to be wanting in these particulars or to have misunderstood one for whose great services in this and other branches of geology no one has a higher esteem than myself. I have, however, in the most careful way, and with these points in mind, read his essay again, anti, taking it as a whole, I cannot gain any different impression of relative magnitudes than the one first received. The importance of the igneous phenomena and the restrictive influence of the processes described by " cementation " in their effect upon the ground-water, as set forth in Professor Van Hise's " Discussion " (Trans., xxxi., 292), impress me as being in very marked contrast with the same things in his first essay. If the point seems to anyone of sufficient importance, it can easily be decided by reading the originals. My paper was the result of some years of observation, reading and reflection, and was meant to be an independent contribution, controversial only in some subordinate particulars. In depicting the drama of the deposition of ores, I cannot but feel that Professor Van Rise assigned to the chorus and the scene-shifters some characters which, it seems to me, should

Jan 1, 1913

By John S. Johnson

The maintenance cost, or renewal cost, in any preparation plant is a large item of expense and reflects in the total cost of producing and preparing the ton of coal. It is given constant study to the end that ways and means of controlling and reducing this proportion of the total cost may be developed. Study of this item of cost has proceeded along usual lines, which are: proper functioning of the maintenance organization; systematic and thorough inspection to prevent breakdonns; the making of repairs before renewals are needed; maintenance work done thoroughly the first time, instead of patching, study of parts needing frequent renewal or repairs or conditions resulting in delays, thorough knowledge of cost by the mall responsible for maintenance; and the use of special equipment and materials. This paper is to deal with special equipment and materials to reduce the maintenance cost hut before going into that I want to express an opinion on the general subject. Maintenance Organization Usually maintenance is taken care of by a group of men who perform their work on the off shift. The work is arranged by the operating official who should be thoroughly familiar with maintenance, so that materials needed may be made up for the particular job and waste of time in looking up materials be prevented. To perfect the maintenance organization, all operating attendants should be thoroughly trained to be familiar with all working parts of their equipment, to make a thorough inspection and to write out the slip for the work required. This requires job analysis, but it is worth the effort, because the attendant usually is better informed than anyone else about his particular equipment. The operating official can judge the scope of the work to direct the repair and to have material ready. Lubrication is an important item in maintenance, and a subject by itself. Usually the breaker oiler is designated to perform this task. This man should be picked for his ability and put in line for promotion to machinist. He should be trained as an inspector, as he is constantly visiting most parts of the breaker and has an opportunity to observe needed maintenance. The first thing is to lay out maintenance work and arrange to have it done; the next is to check the work and see that it has been properly done. This check should be made by the operating official, and through the attendant. The cost statement showing the various items of maintenance cost is not often understood by the man in direct charge. Cost sheets should be simplified and worked up by breaker sections; e.g., the cost of

Jan 1, 1947

By John S. Johnson

The maintenance cost, or renewal cost, in any preparation plant is a large item of expense and reflects in the total cost of producing and preparing the ton of coal. It is given constant study to the end that ways and means of controlling and reducing this proportion of the total cost may be developed. Study of this item of cost has proceeded along usual lines, which are: proper functioning of the maintenance organization; systematic and thorough inspection to prevent breakdonns; the making of repairs before renewals are needed; maintenance work done thoroughly the first time, instead of patching, study of parts needing frequent renewal or repairs or conditions resulting in delays, thorough knowledge of cost by the mall responsible for maintenance; and the use of special equipment and materials. This paper is to deal with special equipment and materials to reduce the maintenance cost hut before going into that I want to express an opinion on the general subject. Maintenance Organization Usually maintenance is taken care of by a group of men who perform their work on the off shift. The work is arranged by the operating official who should be thoroughly familiar with maintenance, so that materials needed may be made up for the particular job and waste of time in looking up materials be prevented. To perfect the maintenance organization, all operating attendants should be thoroughly trained to be familiar with all working parts of their equipment, to make a thorough inspection and to write out the slip for the work required. This requires job analysis, but it is worth the effort, because the attendant usually is better informed than anyone else about his particular equipment. The operating official can judge the scope of the work to direct the repair and to have material ready. Lubrication is an important item in maintenance, and a subject by itself. Usually the breaker oiler is designated to perform this task. This man should be picked for his ability and put in line for promotion to machinist. He should be trained as an inspector, as he is constantly visiting most parts of the breaker and has an opportunity to observe needed maintenance. The first thing is to lay out maintenance work and arrange to have it done; the next is to check the work and see that it has been properly done. This check should be made by the operating official, and through the attendant. The cost statement showing the various items of maintenance cost is not often understood by the man in direct charge. Cost sheets should be simplified and worked up by breaker sections; e.g., the cost of

Jan 1, 1947