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By William R. Patterson

ACCORDING to the phase diagram for the Mn-Ni system,' the high-temperature, fcc y-manganese solid solution is stabilized to below room temperature, in the range approximately 22 to 28 wt pct Ni. However, pearson2 cites evidence in the literature showing that for manganese contents greater than about 75 wt pct the quenched phase in Mn-Ni alloys is fct. This is in keeping with zener's3 suggestion that in manganese-rich alloys the fcc high-temperature phase undergoes a diffusionless or martensitic transformation to a fct structure upon quenching. Work by Basinski and christian4 on manganese-rich compositions in the similar alloy system Mn-Cu established that in alloys of greater than about 82 wt pct Mn the y-manganese phase underwent a fee fct martensitic transformation upon quenching to room temperature. Striking evidence for this martensitic transformation was the highly twinned or banded microstructure, an example of which is shown in Fig. 1. Similar microstructures have also been found in quenched Mn-Cr5 and Mn-Au6 alloys. In the present investigation, we attempted to obtain similar evidence of a fcc — fct martensitic transformation in manganese-rich Mn-Ni alloys. Manganese alloys in the range 10 to 30 wt pct Ni were prepared by arc-melting, under argon, at atmospheric pressure. The alloys all were 50 g in size, and negligible weight loss occurred during melting. The starting materials were electrolytic manganese and nickel, both of 99.9+ pct purity. The alloys were subsequently homogenized 48 hr at 1750°F, hot-rolled 50 pct at 1700°F, annealed 2 hr at 1700°F, and water-quenched to room temperature. All heat treatment was done in purified argon. Both X-ray and metallographic techniques were used to examine the structures of the quenched alloys. X-ray diffractometer studies were conducted on powder specimens obtained from filings rean-nealed 2 hr at 1700°F in argon and water-quenched. Identification of the intensity peaks from the diffractometer counter traces showed that below about 10 to 12 pct Ni the y phase decomposed partially upon quenching to give an a- + ?-manganese structure. In the range approximately 12 to 25 pct Ni, the structure was found to be fct ? manganese with a c/a ratio approaching 1.0 at 25 pct Ni. Beyond approximately 25 pct Ni, the structure remained fcc. These results, including lattice-parameter determinations, are given in Table I. Metallographic examination. was carried out on specimens polished and etched after quenching, and also on polished specimens reannealed and quenched. In the first case, the distinctive twinning or banding so prevalent in Mn-Cu alloys was sought, while in the second, the surface relief effect generally regarded as being truly characteristic of a martensitic transformation was sought. The microstructure of representative alloys in the range 12 to 25 pct Ni is shown in Fig. 2. The structure of the Mn-15 pct Ni

Jan 1, 1965

By L. S. Darken

The manufacture and treatment of metals comprises operations whose effectiveness depends in large measure upon diffusion phenomena. The significance of such phenomena has, for a few simple cases, long been understood, but in more complex cases it has not been adequately recognized. This paper presents a mathematical analysis of some of the cases in which diffusion leads to the formation of a new phase within the metal, and this analysis provides a basis for interpreting quantitatively many apparently diverse experimental observations recorded in the literature, some of which are outlined in the following pages. OBservt1ons Recorded in Literature An outstanding instance is the general type of phenomenon in which diffusion of an element into an alloy is followed by a phase change, which most frequently is a reaction (precipitation) of the diffusing element with one or more components of the alloy to form a compound. Thus in certain alloys heated in contact with oxygen not only the usual oxide scale appears but, in addition, beneath the surface, a well-defined zone in which free oxide particles are dispersed with notabIe uniformity. This zone, commonly referred to as the subscale or zone of internal oxidation, is remarkable in that the visible boundary between it and the unaltered metal is usually sharp. Such a subscale, which appears to have been recognized first in oxidized copper alloys, has been described and studied by C. S. Smith,l by Rhines,2 and by Rhines, Johnson and Anderson;3 but it appears also in other alloys when they are exposed to conditions that bring about the precipitation of some compound, not necessarily an oxide. Another clear case of this same kind is the diffusion of carbon into a steel containing an element such as molybdenum, chromium, vanadium or tungsten, whose carbide is less soluble in iron than iron carbide, the result being that some part of that element is precipitated as a dispersed carbide. A similar phenomenon may occur on the welding of two alloys each of which contains one of a pair of elements that react to form a compound or a new phase of any sort. But in addition to the precipitation of a compound formed from the diffusing element, other effects may result merely from the presence of the diffusing element. For instance, if homogeneous austenite, nearly saturated with respect to carbon, is heated in contact with silicon in the absence of oxygen, one would expect to find, behind the several iron-silicon phases analogous to a scale, a zone of austenite containing dispersed carbide, because of the fact that silicon decreases the solubility of carbon in iron. As still another example, oxidation of an alloy may result in diffusion toward the surface of one or more of the constituents; for instance, during oxidation of a steel containing an element such as "copper, which is less prone to oxidation than iron, there is a notable enrichment of copper just beneath the scale-metal interface. AS an example of a yet more

Jan 1, 1942

By L. S. Darken

The manufacture and treatment of metals comprises operations whose effectiveness depends in large measure upon diffusion phenomena. The significance of such phenomena has, for a few simple cases, long been understood, but in more complex cases it has not been adequately recognized. This paper presents a mathematical analysis of some of the cases in which diffusion leads to the formation of a new phase within the metal, and this analysis provides a basis for interpreting quantitatively many apparently diverse experimental observations recorded in the literature, some of which are outlined in the following pages. OBservt1ons Recorded in Literature An outstanding instance is the general type of phenomenon in which diffusion of an element into an alloy is followed by a phase change, which most frequently is a reaction (precipitation) of the diffusing element with one or more components of the alloy to form a compound. Thus in certain alloys heated in contact with oxygen not only the usual oxide scale appears but, in addition, beneath the surface, a well-defined zone in which free oxide particles are dispersed with notabIe uniformity. This zone, commonly referred to as the subscale or zone of internal oxidation, is remarkable in that the visible boundary between it and the unaltered metal is usually sharp. Such a subscale, which appears to have been recognized first in oxidized copper alloys, has been described and studied by C. S. Smith,l by Rhines,2 and by Rhines, Johnson and Anderson;3 but it appears also in other alloys when they are exposed to conditions that bring about the precipitation of some compound, not necessarily an oxide. Another clear case of this same kind is the diffusion of carbon into a steel containing an element such as molybdenum, chromium, vanadium or tungsten, whose carbide is less soluble in iron than iron carbide, the result being that some part of that element is precipitated as a dispersed carbide. A similar phenomenon may occur on the welding of two alloys each of which contains one of a pair of elements that react to form a compound or a new phase of any sort. But in addition to the precipitation of a compound formed from the diffusing element, other effects may result merely from the presence of the diffusing element. For instance, if homogeneous austenite, nearly saturated with respect to carbon, is heated in contact with silicon in the absence of oxygen, one would expect to find, behind the several iron-silicon phases analogous to a scale, a zone of austenite containing dispersed carbide, because of the fact that silicon decreases the solubility of carbon in iron. As still another example, oxidation of an alloy may result in diffusion toward the surface of one or more of the constituents; for instance, during oxidation of a steel containing an element such as "copper, which is less prone to oxidation than iron, there is a notable enrichment of copper just beneath the scale-metal interface. AS an example of a yet more

Jan 1, 1942

By Robert P. Burrows

Discussion of the paper of R. P. Burrows, presented `at the New York meeting, February, 1916, and printed in Bulletin No. 107, November, 1915, pp. 2237 to 2245. EDWIN M. CHANCE, Wilkes-Barre, Pa.-I have been very much interested in the comprehensive and able discussion of the important topic of mine lighting just given by Mr. Burrows, especially as I know by common report Mr. Burrows' ability and his close touch with the development of the electric mine lamp, and its use in mines in connection with a portable electric lamp. It is regrettable that Mr: Burrows was not able to acquaint himself more closely with the cost of mine illumination, the actual cost, as produced by a portable light as carried by miners, whether a flame safety lamp or an open light. Had he been able to acquaint himself more closely with these data, he perhaps would not have arrived at some of the conclusions which he has presented to us in his paper. For example, we find Mr. Burrows advises that the open torch is by far the cheapest source of illumination, as produced by a portable light. I am very sure that is not the fact. The cost of miners' oil varies from about 25.c. a gallon to 90b. a gallon. The various States have passed laws from time to time rendering it mandatory that the miner shall use, whether he is willing or not, a so-called better or higher grade of burning oil. These laws have entailed the use of an oil so expensive that the use of the oil torch has become practically impossible, and the acetylene or carbide miners' lamp has largely taken its place. I have evolved a few figures showing the relative efficiency and usefulness of the open oil torch and the acetylene miners' lamp. For example, the acetylene miners' lamp consumes or burns 4 liters of acetylene per hour, or 0.14 cu. ft.; the oxygen consumed is 10 liters, or 0.35 cu. ft. per hour; air consumed, 50 liters, or 1.76 cu. ft. per hour; black-damp produced, 40 liters, or 1.41 cu. ft. per hour; air rendered extinctive to the acetylene flame, 112 liters, or 3.95 cu. ft. per hour; carbide con- sumed, 13 g. per hour. The open oil torch, on the other hand, burns about 20 g. of oil per hour; the oxygen consumed is 48 liters, or 1.69 cu. ft. per. hour; air consumed, 240 liters, or 8.47 cu. ft. per hour; blackdamp produced, 191 liters, or 6.73 cu. ft. per hour; air rendered extinctive to oil flame is 1,413 liters, or 49.92 cu. ft. per hour.

Jan 5, 1916

By J. Murray Riddell, Arthur E. Anderson, Grover J. Holt

OUT of the depths of each business cycle we emerge with a stimulus for greater efficiency and a realization of progress in industrial technique. The recent years have not been an exception to this rule, and in retrospect we sense that significant advances have been made in mining practices on the Mesabi Range, with emphasis on speed of production and economy of operation. A survey of such changes does not reveal anything that is fundamentally or basically new, but it is apparent that ideas and machines that have found wide application in industry elsewhere, with necessary modifications, are being put to productive use in mining iron ore. Innovations in transporting and conveying ore from the open pits stand out with greatest prominence, so that, in the main, it will be with these features that this paper will treat, in the review of progress made to this date. The late years have witnessed the development of small deposits for open-pit operation, the cleaning up of pits nearing exhaustion, and in two large operations the approach to the limit for haulage by steam locomotives, owing to grades, making it necessary to recover the ore in slopes, track benches and below the power-shovel limit by a milling and scram operation. For several years small standard-type dump trucks have been used in clean-up or scram operations within the pits, but during the seasor1 of 1936 the first effort was made to use heavy truck haulage in the transportation of stripping and iron ore. The new units in use today vary from 15 to 20 tons in capacity, and are equipped with powerful gasoline or Diesel engines and supplemented by trailers or wagons on rubber or crawler treads. The Diesel engine finds favor with most operators because of fuel economy. These units develop upward of 125 hp. in the 15-ton trucks. The speed of these trucks varies from 2 miles per hour in low gear to 35 in high gear. The transmission affords 12 speeds forward and 3 speeds in reverse.

Jan 1, 1938

By B. K. Miller, R. S. Bradley

THE principal producing areas of fire clay in Missouri are: (I) the east central district, which includes Audrain, Callaway, Montgomery, Warren, and Boone Counties [ ] (Fig. I); (2) the St. Louis district, which includes St. Louis and St. Louis County; (3) the north central Ozark district, which includes Franklin, Gasconade, Osage, Maries, Phelps, and Crawford Counties. Most of the semiplastic[$] fire clay is found in Audrain, Callaway, Montgomery and St. Louis Counties, and in St. Louis. Flint fire clay is found in Callaway, Audrain, and Montgomery Counties and in most of the north central Ozark district. High-alumina diaspore clay is found only in the north central Ozark district, except a few deposits found in Montgomery County. This paper is concerned with the semiplastic fire clay that occurs in the east central Missouri district near Mexico, Audrain County, Missouri, which is mined by the open-pit method as practiced by the A. P. Green Fire Brick Co. About one-fourth of the semiplastic fire clay in that district is mined in shaft mines, and three-fourths in open pits.

Jan 1, 1941

By J. M. Lommel, B. Chalmers

The transfer of material from the solid to the liquid states can be accomplished in several ways. It occurs by the application of heat in the more familiar metallurgical operations of melting but it can also be accomplished by solution in a liquid, as can occur in systems using liquid metals for heat-transfer media. The kinetics of this reaction were studied to learn more of the separate steps in the process. In the case of a pure material at its melting temperature, Te,A,, thermal energy must be supplied to the solid in an amount equal to the latent heat of fusion in order for the solid-to-liquid transfer to occur. The rate at which heat is supplied, and hence the rate of melting, is a function of the temperature gradients in the system. This phase transfer can also occur in the absence of temperature gradients in the system illustrated in Fig. 1, which is a partial phase diagram between the components A and B. A solid of composition CI will

Jan 1, 1960

By Ursula E. Wolff

Il.lechanica1 twins have been observed in brigsten single crystals of a variety of axial orientations defornzed at room temperature in tension or bending. The twins formed near the final fracture and were up to 3 p thick. The twinning plane was always of the type (113). Twinning at room ternperature occurred only after considerable prior slip. Twins usually preceded fracture and nucleated cracks. The crack surfaces often alternated between a (001) plane and the twin interfaces. Secondary twins could also nucleate from cracks. In the absence of twinning tensile samples failed by shear; twinned samples failed by cleavage. On the assumption that observed sudden load drops in the stress-strain curves are associated with twinning, a critical resolved stress for twinning of 60, 000 to 65, 000 psi was calculated. MeCHANICAL twinning has been observed in iron and iron alloys at low temperature by a number of investigators.'-7 Similarly, for high-purity tungsten, twinning has been reported for deformation temperatures below 211°K.8-10 In W-Re and Mo-Re alloys, 20 pct Re was determined as the lower limit for twin formation at room temperature." Since the twins are generally very narrow, they are usually identified only by etching techniques. The expected (112) habit plane has always been confirmed by angular analysis of the surface traces. Recently, however, a complete identification by X-ray analysis has been performed on twins in a Mo-35 pct Re alloy.12 During an investigation of the deformation charac- teristics of tungsten single crystals, twins were revealed in tensile and bend samples deformed at room temperature. This paper deals with the conditions for such twinning and the relation of twinning to fracture. EXPERIMENTAL PROCEDURE Tungsten single crystals, 1/8 in. in diam, of a variety of axial orientations were grown from un-doped material by four-pass electron-beam zone melting. A representative analysis is given in the following table: From these crqstals, tensile samples with 1 in. gage lengths were made by surface grinding, leaving shoulders for gripping. The diameter after grinding was 0.082 in. The distorted surface layer was then removed by ele1:trolytic polishing which reduced the diameter of the gage length to 0.080 in. Tensile tests were carried out at room temperature in an Instron machine under two different sets of conditions: a) Rigid mounting; strain rate 0.02 in. per in. per min. b) Gimbal mounting; strain rate 0.002 in. per in. per min up to a total strain of approximately 0.2 pct, then 0.01 in. per in. per min to fracture. Stress axis and growth direction coincided in all samples and are subsequently called orientation.

Jan 1, 1962

By W. A. Wood, W. H. Reimann, K. R. Sargant

A study is made of the microstructural changes produced in armco and pure iron subjected to alternating torsion at amplitudes above and below the knee of the S/N curve. The aim was to identify the basic mechanisms of fatigue and to find why they should give rise to a sharp S/N knee in contrast to the type of S/N curve shown by fcc metals. It is found that the basic structural change above the knee in the iron is a pronounced cell formation in the grains, which determines irregular micro-cracks, and below the knee a dispersion of fine slip that determines a dispersed pore formation in the grains. Comparison of these changes with those in fcc metals similarly tested shows that they do not include an intermediate structural change, a concentrating of slip in narrow bands with associated slip-band cracking, that characterizes the fcc metals and accounts for their different type of S/N curve. RECENT conferences on basic mechanisms of fatigue emphasize that fatigue damage takes many forms: for example, cracking in slip bands (Thompson1), at grain boundaries and inclusions (Hempel'), at precipitation zones in alloys (Han-stock, Forsythe), or at surface notch-peak effects, both hypothetical (Mott, cottrel16) and observed (Wood). Evidently it is not easy to see in this diversity a basic mechanism. At the same time the contributions suggest that some reconciliation may be possible if distinctions are drawn between three phases of the fatigue process: initiation of damage at nuclei, distribution of these nuclei, and the final macroscopic crack system. In initiation, the relevant features appear to be that nuclei may appear early, at least by 1/100th to 1/1000th of the life of a test specimen; that they may do so at many independent centers, appearing according to some observationsa as pores or voids; and that they are not necessarily self-propagating, damage spreading rather by their multiplication. In distribution, the relevant feature appears to be that they form preferentially in zones where the microstructure becomes abnormally strained (as defined more closely below). Now in these two phases the basic fatigue process should be systematic. But, at the same time, the "abnormal strains" in particular set the stage for considerable diversity in the final phase of macroscopic cracking, for where zones of abnormal strain develop will depend on what kind of fatigue deformation is applied and what kind of prior processing the test material has had. On this view it seems desirable to know what in

Jan 1, 1964

By David A. Sterling, Roger C. Malan

The Atomic Energy Commission is investigating the distribution of uranium and thorium in the Precambrian of the western United States and the relationship of time-space-facies patterns of uranium and thorium enrichment in the Precambrian, to the major resources of umanium in Mesozoic and Cenozoic continental clastic sediments. The results of preliminary studies in the southwestern. United States are summarized. Approximately 50% of the uranium resource of the Free World is in deposits of Precambrian age, principally in lower Proterozoic conglomerates in Canada and South Africa (Uranium Resources, Joint Report, ENEA and IAEA, 1967). Most of the uranium resource of the United States is in Mesozoic and Cenozoic continental clastic sedimentary rocks that fill intracratonic basins. The Atomic Energy Commission (AEC) is investigating the distribution of uranium and thorium in the Precambrian of the western United States and the relationship of time-space-facies patterns of uranium and thorium enrichment in the Precambrian to the major resources of uranium in the Mesozoic and Ce-nozoic host sedimentary rocks. This paper summarizes the results of preliminary studies of the Precambrian in the southwestern United States including New Mexico, Arizona, southern Nevada, and southern California (Fig. 1). The host rock provenances for the major uranium resources in epigenetic deposits of Mesozoic and Ce-nozoic age in the western United States were in areas of extensive Precambrian exposure along the eastern margin of the Phanerozoic geosynclinal belt (Fig. 2). Mesozoic continental clastic sediments in the Colorado Plateau contain about two-thirds of the uranium resource of the United States. These sediments formed from detritus derived from the Mogollon highland in the southwestern United States where the Precambrian was extensively exposed1-1 (Fig. 2). A genetic relationship may exist between this provenance and the major uranium deposits of the Colorado Plateau. The Pre- cambrian might be equally important in the genesis of uranium deposits whether the most important process in the formation of these deposits was the leaching of low-order intrinsic amounts of uranium from Precam-brian granite or from Mesozoic pyroclastics derived from syntexis of the Precambrian basement rocks.' Precambrian Geochronology of the Southwestern United States The Precambrian geochronology of the southwestern United States is in an early stage of systematic study. Until recently, the only basis of correlation was through inconclusive field relationships. However, with the increased use of isotopic age dating, new data are becoming available for correlating regional and local events. As yet, there is no undisputed evidence of ages greater than 1.8 billion years (by) old in the southwestern United States. However, most geologists who have studied the region agree that volcanism and marine sedimentation of predominately eugeosynclinal facies took place in a northeasterly trending geosyn-cline prior to 1.7 by."' Because of insufficient evidence for a pregeosynclinal continental crust, some researchers believe the geosyncline may have developed on oceanic crust.' However, sediments metamorphosed to 1.7 by-old felsic paragneisses in the Panamint Range, California," and southeastward into southern Nevada are believed to have had a nearby continental provenance. The three Precambrian disturbances that are recognized in the southwestern United States are 1.6 to 1.8 by, about 1.4 by, and about 1.1 by-old (Fig. 3). In addition to plutonism, these disturbances are characterized by predominately lower-grade metamorphism. In this report, lower-grade metamorphic rocks include argillite, phyllite, slate, mica schist, and gneiss with relic sedimentary textures. Higher-grade metamorphic rocks, in this report, are recrystallized beyond megascopic recognition of the original rock type. Principal

Jan 1, 1971

By Reinhardt Thiessen

Under sulfur in coal, is usually understood that form of sulfur which is combined with iron and known as pyrite. It occurs in the form of balls, lenses, nodules, continuous layers, thin sheets, or flakes, both in horizontal planes and vertical cleavage fissures. But pyrites also occur as very fine microscopic particles, or nodules, disseminated through the compact coal. This form has had but very little consideration. Finally, there is sulfur in coal in an amicroscopic form (not visible with an ordinary microscope), probably combined with the organic matter that exists in the coal. This form has had considerable attention from a scientific standpoint, but has probably not been recognized enough on the economic side. One or the other, or both, of these two latter forms may comprise the larger part of the sulfur content of coal, especially after it has been washed or otllerwise prepared for use. Pyrites in Microscopic Particles All coals that have been examined by the author contained a varying amount of sulfur in very small globules, or particles, of pyrite. These particles are seen in a thin [section as roughly rounded opaque dots, Figs. 1 to 10. When isolated, they are generally shown to be approximately spherical in shape, with a rough outer surface. They vary in diameter from a few microns to a hundred microns, the majority messuring from 25 to 40 microns; relatively few exceed the latter diameter. They are, therefore, very small objects. Their size is best appreciated by comparing the illustrations, in which they are shown. at a magnifiea tion of 100 diameters, with some known area like the period used in the ordinary printed page. The period is about 0.6 mm. in diameter, and . when magnified 100 times, will cover a circular area of about 2 1/2 in. in diameter, or all but the corners of the illustrations. The illustrations, therefore, represent an area about as large as an ordinary period, and the pyrite globules form but a small part of the total area. Very frequently a number of these particles are joined together in horizontal rows; oc-

Jan 1, 1920

By M. Baeyertr

Since 1915 many papers and books have covered industrial applications of X-rays from various angles. Two of the more recent are a paper by Fink and Archer, which describes in detail the technique of radiography, and a paper by Clark2, which embraces the whole field of X-ray metallogmphy. This paper, therefore, is confined to work of the X-ray Laboratory of the Western Electric Co., which naturally divides into two categories: radiography and diffraction patterns of various types. Radiography Radiography is the field in which the application of X-rays has had most general appeal among the industries which produce or use metals and alloys. Equipment permitting the examination of heavy sections of metals less permeable than aluminum or other light alloys requires apparatus capable of generating hard X-rays over a considerable period of time. The equipment used in the work presented in this paper is practically identical with that described by Fink and Archer in their paper on radiography in industry and is easily capable of penetrating 1/8 in. of lead. Radiography is used in two major groups of problems: (1) in the development of cquipment and tools and (2) in studies of materials. So far there has been no instance in which the use of radiography for routine inspection is justified. This is partly due to the fact that the manufacture of telephone apparatus involves the production of many identical parts by standardized procedures and equipment that has had development and trial before being put on a regular production basis. It is during this stage of development of equipment and tools that radiography has been used to particular advantage.

Jan 1, 1931

By D. T. Peters

To better understand the Co-Mo interaction in maraging steels, the precipitate reversion behavior of two alloys closely related to the 18 Ni-250 grade has been studied. The reversion experiment is carried out by aging at a low temperature, T1 (preaging temperature), for some period of time and then aging at a higher temperature, T2, called the reversion tetnperature. Aging and reversion tmzperatures used were in the range 679 to 1050°F. Reversion is marked by an increase in resistivity and a decrease in hardness. It teas found that some reversion took place at all cornbinations of T1 and T2 but that pronounced rei3ersion resulfed for an Fe-18 pct Ni-5 pct Mo-8 pcl Co alloy exposed to preagz'ng' temperatures at or below 850°F. A similar alloy not containing cobalt exhibited no such discontinuity in reversion behazior with TI. The results are interpreted in terms of two types of molybdenum-rich precipitates, one nucleated at dislocations and the other in the matrix. The increased supersaturation resulting from the presence oj- cobalt evidently provides sufficient energy to nucleate the matrix phase. Anotnalies in the temperature dependence of the resistivity decrease and peak hurdness in the Fe-18 pct Ni-5 pct Mo-8 pct Co alloy as a junction of aging temperature noted in an earlier study are explained on this basis. SEVERAL investigatorsl-9 have studied the details of the precipitation-hardening reaction of the maraging steels. The great majority of conclusions have been drawn from transmission electron microscopy. Although much has been learned by this method, alternate techniques which will give information earlier in the aging process are needed for a more complete understanding of the series of precipitation steps probably involved in the aging reaction. Peters and cupp'' have recently shown, by measurements of the kinetics of precipitation, that an 18 pct Ni-Co-Mo maraging steel shows a distinct change in precipitation behavior at aging temperatures below 850°F. The results were interpreted in terms of the existence of two types of precipitates at low aging temperatures. Only one precipitate type is present at higher aging temperatures. The low-temperature precipitate was found to be a particularly effective strengthener. No evidence for the additional low-temperature precipitate was found in the 18 pct Ni-5 pct Mo ternary alloy. The object of this investigation was to study further the characteristics of the two types of precipitates and the interaction between cobalt and molybdenum characterizing this system. Some preliminary experiments indicated a difference in reversion behavior in specimens aged above and below 850°F. This suggested that knowledge of the reversion behavior might shed some light on these two questions. Hardy and Heal11 have defined reversion as the loss of hardness, electrical conductivity, or other properties caused by heating for a very short time at temperatures above the aging temperature. The precipitate reversion referred to in this paper is entirely distinct from "austenite reversion" often referred to in maraging steel literature. This latter phenomenon could more accurately be called the diffusion-controlled formation of austenite. Much has been written about reversion in several of the aluminum-base binary and ternary alloys.'2-16 Two explanations for reversion have been advanced. Based on the classical nucleation theory of Volmer-Weber-Becker-Doring,17 Konobeevski18 suggested that reversion was due to the size of the precipitate particles

Jan 1, 1968

By William Hamilton Merritt

Since 1880 the occurrence of gold-ore has been known in the Lake of the Woods district. In 1879 the writer examined a so-called silver-location in the lake. More recent developments have extended, south and east, to the Rainy lake and along the Seine river, which flows from the northeast into the Rainy lake. The gold occurs in quartz-veins in the Huronian series. These Huronian rocks occur in belts in the Laurentian; the latter being the predominant formation in the eastern part of Ontario.

Jan 1, 1897

By James Aston

Three years ago the writer presented a paper on the trend of development in the wrought iron industry,' wherein was described a process in the development of which he has been a factor, which at that time had passed through several years of progressive experimental development but which had not then been put upon a commercial scale of operation. The present paper deals with two years of observation and experience in the commercial operation of a plant by the A. M. Byers Co. at Warren, Ohio. It will not enter into the controversial field of the relative merit of wrought iron and steel in various classes of service, nor will it elaborate upon the characteristic services or fields of utility to which wrought iron is particularly adapted. It is sufficient to state that the wrought iron industry is upon a substantial basis and that the material finds service in pipe, where its advantages are in superior corrosion, fatigue, welding and threading qualities; in bar iron for staybolts, engine bolts, and rivets, demanding maximum service against corrosion and fatigue; in plates for corrosion service; and in chains, because of welding and shock-resisting characteristics. In short, ability to withstand the stresses of shock and vibration, or the ravages of corrosion, to hold protective coatings, and to give maximum efficiency in welding, are its features of relative superiority. If these features were not well recognized, the wrought iron industry would have shrunk to insignificance in the face of high costs and acknowledged limitations in manufacture. To charge that this industry is built upon a structure of assumption, psychology, and improperly weighed evidence is an impeachment of the integrity or belittling of the powers of observation of users through many centuries of service experiences. In a history which extends to prehistoric time, and which is linked up with the earliest records of ferrous products, the dominant method of manufacture, as we have known it for little over a century, occupies a very small niche in the span of years that mark production and use of wrought iron. Puddling, the outstanding manufacturing method of

Jan 1, 1929

By A. L. Barnes

Residual oil in watered-out reservoirs is a tremendous reserve which has been unrecoverable by established production methods. A study of the new recovery methods indicated that the forward combustion urocess might- recover oil from such reservoirs; however, no thermal recovery operating experience in a watered-out system was available. The Delaware-Childers pilot thermal test was undertaken to test the feasibility of thermal recovery in this watered-out reservoir. The pilot test consisted of a 2.22-acre, inverted five-spot in the 600-ft deep Bartlesville sand. The reservoir in the pilot area had a porosity of 20.6 per cent, a permeability of 118 md and an average sand thickness of 45 ft. The reservoir contains a 33' API, 6-cp oil. Combustion was started Nov. 22, 1960. The initial air injection capacity was 750 Mscf/D, but it was eventually increased to 2,000 Mscf/D. The test was surrounded by an active water flood; therefore, water production was initially high, but decreased as the heat wave moved toward the producing wells. Oil-bank arrival at an individual well was indicated by a drop in GOR and WOR, and an increase in oil production. Combustion-front arrival was evident at three of the pilot producers, and they were plugged. Cumulative oil production from pilot area wells war over 12,000 bbl. Operational difficulties were negligible and only conventional equipment was necessary. The combustion efficiency of this test averaged over 80 per cent. Results from coring showed that the leading edge of the combustion front tended to be wedge-shaped but a nearly complete sweep of the reservoir was eventually obtained. An isopach map based on evidence from 10 core holes and the existing wells showed that 126 acre-ft had been swept by the heat wave. Using this swept volume, an air requirement of 15.7 MMscf/acre-ft was calculated. It was calculated that 275 ,STB/acre-ft was consumed bv the heat wave. INTRODUCTION There is a large amount of oil remaining in reservoirs that have been water flooded. A study of ways to recover this oil showed that the forward combustion process might be applicable. Results from a number of forward combustion tests have been reported in the literature, but none of these tests were conducted in a watered-out system. The Delaware-Childers pilot thermal test was initiated in 1960 to define the operating characteristics of underground combustion in this watered-out Bartlesville sand reservoir, The purpose of this paper is to present the pilot test results in detail. FORWARD COMBUSTION PROCESS The forward combustion process consists of initiating combustion in the formation surrounding an injection well and driving this heat wave through the formation toward offset producing wells. As the combustion front progresses through the reservoir, oil and formation water are vaporized, driven forward in the gaseous phase, and recon-densed in the cooler part of the formation. These distilled liquids, water of combustion and gaseous combustion products, form a bank or three-phase region ahead of the burning front. This bank pushes mobile reservoir fluids toward the production wells. The rate of movement of the combustion front is controlled by the rate at which the nondistill able residue which serves as process fuel can be completely burned off the sand. The production performance from a heat wave conducted in a watered-out oil reservoir will differ from one conducted in a dissolved gas-depleted reservoir because of the difference in fluid saturations. The primary depleted reservoir contains connate water saturation, relatively high oil saturation and some gas saturation. The watered-out reservoir contains a highly mobile water saturation, residual oil saturation and little gas saturation. As the combustion front moves forward in either type of depleted reservoir, it drives the distillable oil, the water in place and the water of combustion ahead, and burns the nondistillable portion of the oil. The heat-wave process in a watered-out reservoir differs from the process in a

Jan 1, 1966

By H. M. St. John, T. Rynalski, G. K. Eggleston

Maintaining a satisfactory structure in brass and bronze castings has always been a foundry problem of great practical importance. While metallurgists and scientific investigators have not entirely ignored this matter, it has received less of their attention than has been given to iron, steel and the wrought copper and aluminum alloys. Investigation in this field has probably been discouraged to some extent by the complicated nature of the alloys involved. Hundreds of alloys are in more or less common use, most of them containing copper, zinc, lead and tin in widely varying proportions. They also contain appreciable percentages of iron and antimony as impurities, and often phosphorus, which has been added as a deoxidizer and fluidifier. Small amounts of sulfur are usually present. It is not uncommon to find nickel, sometimes in rather substantial quantities. Traces of other metals are frequently present. So complicated and variable a mixture obviously offers difficulties in any investigation of the various factors that influence the structure and other properties of the casting. Incipient Shrinkage Bolton and Weigandl have called attention to a type of structure characterized by intercrystalline fissures and large dendritic crystals which are frequently tarnished to an orange or reddish brown color. This intercrystalline porosity they term "incipient shrinkage" and attribute to the presence of carbon monoxide in the atmosphere under which the metal was melted. The defective structure to which Bolton and Weigand refer has become a brass-foundry problem of major importance, because it occurs with distressing frequency in leaded brasses and bronzes when these are melted in a neutral or reducing atmosphere. Since the electric furnaces, now coming into general use in brass foundries, normally operate with such an atmosphere and, in fact, depend upon it in part

Jan 1, 1930

By George E. Cole

While many parts of Canada's pre-Cambrian shield are well served by railway, it is frequently necessary for prospecting purposes to proceed farther into areas inaccessible by rail. To such areas in summer the canoe was at one time the accepted means of travel for the prospector while the dog team was much used in winter. Although summer travel was much improved by the development of the outboard motor, the lack of facilities for cheap transportation has been a serious hindrance to the employment of capital in opening up the distant fields. The pre-Cambrian surface of Manitoba, like that of Ontario, is hummocky, with rounded hills and ridges of rock alternating with basinlike depressions and valleys occupied by lakes and rivers Or by many low-lying portions covered with muskeg' Routes to the mines have not usually been direct or easy and seasonal vagaries have presented problems in themselves. In summer, water transportation may be the cheapest method for the longer distances but it is not every water route that will satisfy the conditions of loading freight on to a boat or scow and of conveying it without interruption to its destination. By its location, a mine may require a large program of boat transportation in summer Over part of its route, to be followed by winter freighting for the remainder. In order to carry on development and produc- tion over a long period, it may be necessary to haul large quantities of supplies during the winter. This seasonal problem, particularly for the out-of-the-way properties, is SO important and demanding as to make it a major operation in the life of the mine. The -use of the tractor during winter months for heavy machinery and bulk supplies, and the use of the airplane throughout the year for the transportation of personnel and for emergency requirements, have greatly improved transportation to places that are inaccessible by rail. Canada has pioneered in both these methods. Development oF Transportation Twenty-two years have seen a marked change in transportation methods in Canada's mining country. Horse-drawn sleighs have given way to the tractor and that to some extent has been supplanted by the airplane. One of the earliest ventures involving transportation of considerable magnitude was that of the Mandy mine, on Schist at in northern Manitoba. According to accounts of early mining activities in Manitoba, the Mandy mine, beginning December 1916, had 3300 tons of ore hauled 40 miles by sleigh to Saskatchewan River and in summer this was conveyed by barge to The Pas, 130 miles, and then by railroad to Trail, British Columbia, 1200 miles. The mine shipped 6000 tons of ore in 1918 and 15,000 tons in 1919. In winter of the latter year, as many as 300 teams of horses were used on the 40-mile stretch to

Jan 1, 1943

By George E. Cole

While many parts of Canada's pre-Cambrian shield are well served by railway, it is frequently necessary for prospecting purposes to proceed farther into areas inaccessible by rail. To such areas in summer the canoe was at one time the accepted means of travel for the prospector while the dog team was much used in winter. Although summer travel was much improved by the development of the outboard motor, the lack of facilities for cheap transportation has been a serious hindrance to the employment of capital in opening up the distant fields. The pre-Cambrian surface of Manitoba, like that of Ontario, is hummocky, with rounded hills and ridges of rock alternating with basinlike depressions and valleys occupied by lakes and rivers Or by many low-lying portions covered with muskeg' Routes to the mines have not usually been direct or easy and seasonal vagaries have presented problems in themselves. In summer, water transportation may be the cheapest method for the longer distances but it is not every water route that will satisfy the conditions of loading freight on to a boat or scow and of conveying it without interruption to its destination. By its location, a mine may require a large program of boat transportation in summer Over part of its route, to be followed by winter freighting for the remainder. In order to carry on development and produc- tion over a long period, it may be necessary to haul large quantities of supplies during the winter. This seasonal problem, particularly for the out-of-the-way properties, is SO important and demanding as to make it a major operation in the life of the mine. The -use of the tractor during winter months for heavy machinery and bulk supplies, and the use of the airplane throughout the year for the transportation of personnel and for emergency requirements, have greatly improved transportation to places that are inaccessible by rail. Canada has pioneered in both these methods. Development oF Transportation Twenty-two years have seen a marked change in transportation methods in Canada's mining country. Horse-drawn sleighs have given way to the tractor and that to some extent has been supplanted by the airplane. One of the earliest ventures involving transportation of considerable magnitude was that of the Mandy mine, on Schist at in northern Manitoba. According to accounts of early mining activities in Manitoba, the Mandy mine, beginning December 1916, had 3300 tons of ore hauled 40 miles by sleigh to Saskatchewan River and in summer this was conveyed by barge to The Pas, 130 miles, and then by railroad to Trail, British Columbia, 1200 miles. The mine shipped 6000 tons of ore in 1918 and 15,000 tons in 1919. In winter of the latter year, as many as 300 teams of horses were used on the 40-mile stretch to

Jan 1, 1943

By J. L. Brimhall

Slip-line formation during bending has been studied on neutron-irradiated molybdenum single crystals. For equivalent strains, the slip lines are coarse and distinct in the irradiated molybdenum and not resolvable in the unirradiated molybdenum. The slip lines have been directly correlated with dislocation channels present in the irradiated and deformed thin foils. The heterogeneous distribution of the dislocations during deformation in the irradiated material results from dislocation interaction with the dejects produced during irradiation. Impurities , in the form of' carbides, affected the dislocation channeling Principally by acting as dislocation sources. ALTHOUGH the mechanical behavior of irradiated materials has been studied extensively, the precise mechanism of irradiation hardening has not been established. Some information on the microstructural species responsible for hardening of irradiated materials has been derived from direct and indirect observations. The direct observation of the structure of deformed irradiated metals, particularly by transmission electron microscopy, is a relatively new and unexplored area. Slip-line studies in fcc metals have been restricted primarily to copper.1-3 Very coarse slip lines, representing slip on many closely spaced planes, have been observed in deformed, irradiated copper. Coarse slip lines have also been observed in irradiated aluminum.4 Clear channels in irradiated copper caused by dislocation motion through the defect structure have been seen by transmission electron microscopy and correlated with slip lines.5-6 To date, little work has been reported on the irradiated bcc metals. Eyre described the slip lines around hardness indentations on irradiated iron and found them to be more distinct than lines in unirradiated material.' Mastel et al.' have observed channels in deformed irradiated molybdenum similar to those reported in copper. As part of a program concerned with the effect of neutron irradiation on metals, the slip-line

Jan 1, 1965