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By Robin O. Williams

The increase in internal energy as the result of deformation has been measured for lead, aluminum, silver, nickel, iron, and zirconium by using rapid, adiabatic compression. The stored energy increase is roughly Proportional to the strain; the propor-tionality constant increases rapidly with increasing melting point. The fraction of the mechanical energy which is stored increases more slowly, since the strength of the metals also increases with melting point. The values of the stored energy are considered accurate to about 10 pet. The present values appear about 50 pet larger than the more reliable published results where comparisons are possible. It is possible that this difference is due to the high strain rate used in this investigation. Immediately after deformation all these metals release energy at a rate roughly proportional to (time)-'. This release is considered to be associated with dislocation motion but in aluminum (and copper) some additional process seems to be present. This release can represent 20 pet or more of the stored energy. WHEN pure metals are plastically deformed, most of the mechanical energy is converted into heat. The energy remaining within the metal is significant in that it is the energy of the disorder produced and thus detailed knowledge of this energy is a powerful tool in understanding the nature of deformational disorder. While much effort has been expended on this problem, the amount of information available is limited. The situation as of 1958 has been carefully reviewed by Titchener and ever.' The present results have been obtained by a new experimental approach to this problem. The method necessitates high-strain rates which make comparisons with published results less certain, but a high-strain rate is an advantage in that the energy release immediately after deformation can be followed. EXPERIMENTAL PROCEDURE In the experimental method used, the internal (stored) energy is given as the difference between the mechanical work used in deforming the sample and the heat which is released (the first law of thermodynamics). The work is supplied by two identical hammers swinging freely from a fixed height, the available energy being the product of the mass, the gravitational constant, and the distance through which the center of gravity moves. The initial temperature rise of the sample represents the heat produced by the deformation. The sample temperature is determined by a small thermocouple embedded in and supporting the sample. This process can be repeated over and over to produce increased strains. Most samples are run through about five cycles to a total strain of around 0.7. Further details are covered elsewhere. The determination of the heat is dependent upon the sample weight, its specific heat, the rise in temperature, and any gains or losses to the surroundings. One is dependent on published results for specific heals (the values were taken from a collection).3 The values must be accurate to about 0.1 pet in order that they not affect the results. The best values thus do not contribute to the uncertainty, but this is probably not always the case. The accuracy of the temperature rise is limited primarily by knowledge of the thermocouple characteristics over short temperature intervals, but careful calibration eliminates this as an important factor. One can calculate readily the heat flow between the sample and hammers if the time of contact and the sample temperature are known and if there were no oil at the interface. Assuming the maximum temperature difference, upper values for this interchange have been calculated (the time of contact is determined from the decrease in sample length) and it may or may not be significant. However, no correction is colnsidered necessary because of the presence of a thin oil film which has a thermal conductivity much less than the metals. Except for the possible uncertainty in specific heat, the heat is considered to be adequately known. The mechitnical losses which are recognized as important are: 1) friction between the sample and the hammer:;, 2) the kinetic energy in the hammer suspension system which may not be entirely usable, 3) the rebound energy of the hammers, and 4) the vibration of the hammer heads. All these have been covered in detail elsewhere2 and only the more significant points are made here. The friction turns out to be small except for soft materials (lead)

Jan 1, 1962

By W. H. Bassett

ALTHOUGH brasses and bronzes have been made for ages, a systematic study of their physical properties has been carried out only during the years of the present century. Among these properties may be included those which are to be detected by means of microscopic examination; in other words by the science of metallography. The earlier workers in this field, both in this country and abroad, gave their attention to steel. When the senior author explored the situation in 1902, there was little encouragement to be found in undertaking the study of the non-ferrous alloys. A start was made, and the metallography of the brasses and bronzes, as well as of the copper-nickel- zinc alloys developed materially under his direction. Annealing experiments were begun in 1902, and in the succeeding years the effect of temperature, and the influence of previous working, on the grain size of brass were studied. The conclusions so well known and widely published today were largely reached during those earlier years. In 1905 the first complete annealing series were made. By this it is meant that brass and copper sheet, 5 B & S Nos. hard, was machined into tensile test specimens, then annealed under accurate control for 30 min. at temperatures up to the melting point of the material. Various determinations were made, including tensile strength and elongation in 2 in. There rapidly followed similar series on all of the copper-zinc alloys from 100 to 60 per cent. copper, on the bronzes, cupronickels, and on copper-zinc-nickel alloys. At this point there was published by Grard, in October, 1909,1 the very comprehensive and complete work on the tensile properties of cartridge brass, 90-10 copper-zinc, and electrolytic copper. The excellent photomicrographs in that paper illustrated the changes in structure produced by cold rolling as well as by annealing at different temperatures, but where Grard's work was confined to copper and to two alloys, the investigations in this laboratory have been over the entire fields of the commercial copper-zinc alloys, copper-tin alloys, representative copper-nickel and copper-nickel-zinc alloys as well as aluminum bronzes and others of a more special nature.

Jan 1, 1927

By Robert A. Colten, Frederick C. Hull, Robert F. Mehl

It is known that pearlite forms from austenite by a process of nucleation and growth, and that the rate of formation of pearlite may be described by a rate of nucleation and a rate of growth.l,2 The manner in which these two quantities operate to produce the observed isothermal reaction curve has been analyzed in a paper published in I939.3 Two types of process were described: (I) that in which nucleation occurs at the grain boundaries of the parent phase, with the nodules growing toward the centers of the grains, initially as hemispheres and then after impingement as roughly radial-columnar structures; and (2) that in which nucleation occurs generally, with the nodules growing to full spheres until impingement with other growing nodules restricts growth. Both cases are met in the formation of pearlite from austenite (Fig. I);2,4 the former, occurring near the knee of the S-curve, has been named "grain-boundary transformation," and the latter, occurring at temperatures near Ael, has been named "group-nodule transformation." In developing our knowledge of the factors that determine the rate of formation of pearlite from austenite, it is important1,2 to obtain data on the rate of nucleation and the rate of growth of pearlite. Such data, when obtained near the knee of the S-curve, will furnish information of use in understanding the factors that affect hardenabil-ity; when obtained at higher temperatures, such data will be useful in understanding the behavior of steels that during heat-treatment react to pearlite.2 It is the purpose of this paper to present data on the rate of nucleation and the rate of growth of pearlite in dependence upon composition, grain size, temperature, and the degree of homogeneity of the parent austenite. The studies are restricted chiefly to plain carbon commercial steels." Previous Data on Rate of nucleation and rate of Growth Data on the rate of nucleation and the rate of growth of pearlite have been published by Scheil and Lange-Weise,5 by Mirkin and Blanter,6,7 by Meh1,l and by Dorn, De Garmo and Flanigan.2, It is difficult to interpret the data, for in most cases too little information is given on austenitizing temperatures and times, the state of homogeneity of the austenite (presence or absence of carbide, etc.), austenite grain size, and mode of formation of pearlite at the temperatures given. Except for the approximations of Mehl and the work of Dorn, austenite grain size was disregarded, though it is well known

Jan 1, 1942

By Leon W. Dupuy

INTRODUCTION A BRIEF elemental discussion of the fundamental factors involved in diamond drilling often fills a need, particularly when a mine operator is contemplating for the first time an exploratory drilling campaign. Mr. James A. Barr, of the Mining Methods Committee of the Institute, has suggested that many engineers must undertake a drilling program of one kind or another and, in the case of diamond drilling, sometimes even are at a loss as to how to start correspondence. The Bureau of Mines has acquired much experience in managing exploratory diamond-drilling activities. Its activities in diamond drilling included exploring for potash in Texas, Utah and New Mexico 1-4 during the 1920's. The Strategic Minerals Exploration program was started in 1939 and was materially expanded during the war to include critical and essential minerals. At the peak of its war-time activity more than 200 engineers were employed, a majority of whom supervised diamond drilling. Many of them had little experience with such work prior to their employment with the Bureau, and it was necessary to instruct them in their duties. The purpose of this paper, therefore, is to present the fundamentals of exploratory diamond drilling from the viewpoint of management in such a way that they will serve as a basis on which those beginning exploratory diamond drilling may build an experience and acquire ability to direct exploration as they gain that experience. SELECTION OF METHOD OF DRILLING Selection of the method of drilling is governed by the type of material to be penetrated and by the type of sample needed to determine the quality and importance of a deposit. Types of drills that might be used for a given job include diamond drills, churn drills, hand auger drills, power auger drills, bucket drills, and rotary drills (sometimes called "seismograph rigs"). Each type has a specific field in which it is most useful. While the Bureau of Mines utilized all the types of drilling mentioned, diamond drilling was used on a majority of its exploratory projects. FACTORS GOVERNING SELECTION OF DIAMOND DRILLING The prime consideration in selecting a method of drilling is first to determine what results are desired and then to choose a method that will furnish reliable data in the ground to be penetrated. Use of diamond drills permits recovery of a core as well as sludge at a comparatively low cost. The core provides an excellent means of studying the formation being drilled and furnishes much information that would be difficult to obtain otherwise. Diamond drills will recover a satis-

Jan 1, 1947

By M. M. Fine

THE problem of producing a uniform, medium-fine sand for glass-furnace feed has been of interest to the glass-container industry for many years. In the present investigation of the problem, conducted by the Bureau of Mines in cooperation with the Owens-Illinois Glass Co., Alton, Ill., a satisfactory method of producing such sand was developed. The investigation involved continuous-grinding studies of glass sand with flint and porcelain pebbles, steel balls and rods, and a simultaneous study of classification. The most satisfactory procedure consisted of grinding in a pebble or ball mill followed by a double classification: hydraulic classification to separate the oversize for return to the grinding unit and mechanical classification to remove fines and impurities from the ground sand. The proper application of this flowsheet usually yielded a graded sand containing less iron than the feed even when grinding was done in a steel-lined ball mill. The amount of sand ground into the so-called "dusting" sizes was, in all cases, less than 10 pct. Experiments were made which showed that this very fine sand could be beneficiated to a usable material. Background The advantages in utilizing a uniform, medium-fine sand as a feed for glass furnaces has motivated a considerable amount of research on the ,problem of producing such sand by glass producers and others. For the glass producer, the faster melting rate of such a graded sand offers the possibilities of reduced fuel costs and increased furnace capacity. In addition, there is the likelihood of improving the quality of the melt and thereby reducing the number of seeds (air bubbles) and stones (unrnelted grains) in the finished ware. Although the melting rate of a glass batch depends on other factors in addition to the grain size of the sand, there is experimental evidence to show that grain size influences the melting rate considerably. Potts, Brookover, and Burch' found that when the raw materials (sand, soda ash, and limestone) were always matched in- size, there was a great decrease in the melting time as the grain size of the materials was decreased. They found, too, that when the grain sizes of the soda ash and Limestone were held constant at 40 to 60 mesh, the minimum melting time occurred when 40 to 60 mesh sand was used. The increase in melting time with decrease in grain size beyond 40 to 60 mesh was due, they postulated, to accelerated demixing or separation of batch during melting as the grain size of the sand decreased in relation to the grain size of the other materials. An earlier investigatora found that the highest rate of melting and purifying ordinary glass was obtained when medium-size sand (0.385 to 0.120 mm, correspondingly roughly to 40 to 120 mesh) was used. Although batches containing smaller-size sand were found to fuse more rapidly, the time required to remove air bubbles from such melts actually increased the total duration of the process. Coarsegrained sand, it was stated, increased greatly the times of both melting and purifying. Although the laboratory data are difficult to confirm on a plant scale, observations by the Owens-Illinois Glass Co. indicate a higher furnace capacity of better-quality ware when a medium-fine sand is used in the batch. During the recent war, the glass producer was inclined to overlook a considerable variation in raw materials in the interest of higher production. For instance, table I shows the wide range in the amounts of various screen fractions in sand supplied by one producer to the Terre Haute plant of Owens-Illinois. The sand, from the northern Illinois St. Peter sandstone, represented material used by that plant over a period of a few years during the war. Since the war, the glass industry has insisted on

Jan 1, 1951

By R. Maddin, C. H. Mathewson, W. R. Hibbard

According to conventional crystal mechanics, a face-centered cubic single crystal slips on the system {111} <110> which receives the highest shear stress in terms of the stated orientation of the stress axis of the crystal.l However, in brass, the slip process is never as simple as this conventional analysis indicates. There is always a second cooperating plane which contains the same slip direction as the primary plane.2&apos;3 There is still another cooperating slip system commonly called the conjugate system3 previously observed to function with considerable lag only after the rotation due to the action of the first plane had produced a symmetrical condition of equal shear stress on the two systems. In the 1943 Campbell Lecture,4 a slip mechanism was outlined in which the {111) planes moved step-wise in two adjacent <112> directions integrating into the <110> slip direction. "... the slipping process would be visualized as a succession of steps 30" to the right and left of the resultant, microscopically observed, slip direction; a first step setting up the twinned configuration in the single spacing involved and an ensuing slip returning the atoms to the untwinned configuration while completing a fully integrated <110> movement."4 This process is shown diagrammatically in Fig 1 which shows two close packed layers of atoms at a slip site. A movement of the full circles through the "valleys" into the adjacent sites would produce a twin configuration with respect to the open circles. The term, "twin fault," seems most appropriate to define this faulted condition of the lattice. Annealing twins in face-centered cubic metals may arise from preformed nucleii which could be described as twin faults produced by the first movement of this two stage slip process. However, it is clear that this kind of slip does not take place so as to embrace a measurable number of adjacent planes because careful X ray examination has not conclusively shown the existence of ponderable twin lamellae (as in the case of Neumann bands in the body-centered ferrite). In view of the imponderable character of these hypothetical twin faults, the search for evidence of their existence seems restricted to indirect methods. The most obvious experimental technique serving this purpose is the determination by micrographic and X ray methods of the alignment of the composition planes of annealing twins with the former slip planes in axially strained and recrystallized single crystals. In previous attempts of this sort not all of the annealing twins could be traced to slip planes known to be operative in the conventional sense and hence evidence appeared negative or inconclusive. With the discovery of additional slip systems2&apos;3 operating in conjunction with&apos; the major system of highest resolved shear stress in axially strained brass it became apparent that the simple technique outlined above might be re-employed with more gratifying results. If, on annealing single crystals of alpha brass previously strained in tension, twins are found with their composition planes parallel to all three operative slip planes and with no participation of the fourth plane there is good evidence in favor of the existence of twin faults and of the two stage slip process. Experimental Procedure and Resuits Single crystals of alpha brass of the 70-30 composition were grown by solidification from the molten state.

Jan 1, 1950

By C Macquarie, Maurice Cook

Normally the grain size of cold-rolled and annealed copper sheet is of the order of 0.02 to 0.06 mm., and 0.1 mm., for example, would, for many purposes, be regarded as undesirably large. The occurrence of very large grain sizes in a few isolated cases of copper sheet led the authors to inquire into the causes giving rise to such unusual results. During the course of this work a very large number of experiments have been carried out to determine the effect of varying the conditions of the final and penultimate rolling and annealing operations, as well as of earlier rolling and annealing treatments. A correspondingly large number of observations have been made, but within the space of one paper it is possible only to outline relatively briefly what appear to be the more important of these experiments and observations. The presentation of the results does not follow chronologically the order in which the experiments were carried out and they have been rearranged for the sake of simplicity. In recent years a considerable amount of work has been done in connection with the recrystallization and grain growth in metals arid alloy. that take place on annealing, and a number of generalizations have beell reached. It is known that the crystal size in wrought material in the annealed condition depends on a number of factors, including the time and temperature of the annealing operations and the nature and amount of cold-work to which the material has been subjected. Results. however that are not covered by these generalizations can be obtained, which, in some instances, may even appear to be contradictory to them. Xccortling to these generalizations gradual changes in grain size are effected by progressive variation of the factors involved in annealing or cold-working. The work recorded in the present paper, however, relates to the development of grain sizes which are far beyond those normally encountered in ordinary annealing operations and far in excess of grain sizes which,

Jan 1, 1939

By H. D. Hoskold

This paper is presented in fulfillment of the promise made in my paper, " Remarks upon Surveying-Instruments,"" etc., and much of the material which would constitute an appropriate introductioil here is omitted, because it has been already published by the Institute, in connection with my own contributions- or those of Mr. Scott and others, in vols. xxviii. to xxxi. of the Transactions, and in the special Institute volume on Mine-Surveying Instruments. In these preceding publications will be found, for instance, descriptions of the writer&apos;s " miner&apos;s transit-theodolite" of 1863,† and his later " angleometer,"‡ both of which were steps of the progress in engineering instruments and methods which originated in the work of Bourns, before 1842, on the " BoxTunnel " of the Great Western railway in England, in which he had to make connections by direct telescopic sights down the shafts. About 1870 the writer devised a practical and much superior plan, and made detailed drawings for an instrument to meet all the conditions he had proposed prior to that year. The detailed plans were communicated to a celebrated optical firm in London; but, owing to their loss (in Paris or Germany, it is believed) and to other reasons, the matter was, for the time, allowed to lapse. Following upon Bourns&apos;s idea, my friend, the late Mr. Beansland, introduced, in 1856, a new system and a portable astronomical instrument.§ Such instruments, however, were neither common nor convenient, and did not come into general use among engineers.

Jan 1, 1902

By J. P. Hirth, G. M. Pound

The flux of evaporation J from {loo) , {111), and (110) planes of silver single crystals and from poly crystalline specimens was measured at 744°C under a high vacuum using a time average weight loss method. The evaporation coefficient a was computed from the measured flux and vapor pressure data through the relationship J = aPe/21rmkT. The evaporation coefficients for the close packed planes and the poly crystalline specimens were found to be about 0.4 providing tentative confirmation of the theoretical limiting law for evaporation of metal crystals, a = 73(P/Pe) + % . The (110) planes faceted to form (111) planes, resulting in a greater evaporating area and larger a . The evaporation morphology of the plane surfaces and the surfaces of spherical single crystals is described in some detail. RECENTLY a detailed theoretical analysis of the mechanism and kinetics of metal crystal evaporation was made.1&apos;2 A mechanism for vaporization involving the recession of monatomic ledges across a metal surface was deduced, and evaporation rate equations were derived by considering the dynamics of these ledges. In most metals, the process of evaporation is one of dissociation of atoms from ledges, surface diffusion, and desorption. The gross vaporization rate is controlled by the surface diffusion and desorption rates. It was shown that the monatomic ledges, under the action of surface diffusion gradients, tend to assume a terminal velocity and spacing. Further, it was shown that crystal edges and grain boundaries are a ready source for monatomic ledges. In the case of evaporation of large, perfect crystals with clean, low-index surfaces, the kinetic treatment1 leads to a limiting law for crystal evaporation: where J is the gross flux of vaporization, a is the evaporation coefficient, Pe the equilibrium vapor pressure, m the atomic mass, k Boltzmann&apos;s constant, T the absolute temperature, and P the actual pressure of vapor over the crystal surface. Imperfections such as grain boundaries, pores, cracks, and macroscopic steps should have the effect of causing positive departures from this limiting law. Such an imperfection is a source for monatomic ledges, which, near their origin, are closely spaced and thus give rise to higher evaporation rates there. However, under many experimental conditions,&apos; this effect should be negligible due to the relatively low concentration of imperfections. In general, a more important cause of positive departure should be screw dislocations, and the effect of these has been considered in some detai1.2,3 Monatomic ledges emanate from points where the surface is intersected by a dislocation with a screw component normal to the surface. The dynamics of ledges arising from a screw dislocation are similar to those of ledges arising from a crystal edge. There is a perturbed region near the origin where the monatomic ledges are, under certain experimental conditions, closely spaced and the

Jan 1, 1960

By E. I. Radzinovsky, D. W. Dareing

This paper presents theory which is used to predict rock-bit bearing life reduction due to simple harmonic variations in bit forces. The theory is based on the premise that if a constant load acts for a certain fraction of the life which the bearing would have if that constant load were applied for its entire life, then the same fraction of thelife of the bearing is consumed. Total bearing life is related to simple harmonic variations in bearing life associated with instantaneous bearing loads. The results show that rock bit bearing life is not affected appreciably by forces commonly impressed upon a bit, but it is affecied appreciably by relatively large dynamic bit forces occasionally encountered during drilling. In addition, the results show that the life of sealed bearings is more sensitive to bit force variations than is the life of unsealed bearings. INTRODUCTION Roller bearings are important components in roller cone rock bits because they transmit a large portion of the drill collar weight to the formation being drilled. Unfortunately, they have a relatively short life under down-hole drilling conditions. Roller bearings are usually the first bit components to fail, and their failure leads immediately to failure of the entire bit. Short roller bearing life, and thus short bit life, is due mainly to high unit loads transmitted by the bit and to the adverse environment in which the bearings operate. The results of the study discussed in this report show how dynamic bit forces also affect roller bearing life. The purpose of this paper is to discuss theory developed to predict the effect of different magnitudes of periodic bit forces on roller bearing life. Theoretical results are used to compare the life of rock bit roller bearings subjected to steady forces to the life of rock bit roller bearings subjected to unsteady forces similar to the type of unsteady forces measured at the bit with a special downhole recording instrument. BACKGROUND AIanufacturers of bearings have conducted laboratory tests which show how bearing life is affected by steady bearing load. 1 The well-known empirical equation which defines bearing life follows from bearing test data. It is: where L = bearing life, hr P = bearing load, Ib C = constant q = exponent (constant). The effect of environment on bearing performance is manifested through the exponent q and the constant, C. King,2 in similar tests conducted on roller bearings used in rock bits, showed that, in addition to the load, the environment (abrasive materials, chemical components, etc.) greatly affects bearing life. His data, which show how the life of roller bearings in a 7-7/8-in. W7R bit rotating at 60 rpm is affected by bit weight and fluid environment, are displayed on a log-log plot by broken lines made up of straight line segments. Each broken line corresponds to a given environment. One segment (q = 1.4) of the broken line corresponding to a fluid environment of barite mud is shown in Fig. 1 along

Jan 1, 1966

By G. K. Manning, C. H. Lorig

TWO metallurgical tools have acquired wide use within the past several years as a means of studying the transformation characteristics of steel. One is a technique used first by Bain and Davenport for determining the transformation characteristics of a steel at constant temperature; the second is the end-quench hardenability test. Constant-temperature transformation curves like those of Bain and Davenport have done much to rationalize the metallography of steel; however, in commercial practices, constant-temperature transformation is seldom encountered, therefore only rarely can such curves be directly applied. The real reason for the determination of such curves lies in the fact that they provide a way of thinking about transformation that is both convenient and productive. The end-quench hardenability test is a more practical means of studying transformation, for, by correlating positions on the hardenability bar with shapes of different masses, an almost direct application of the results can be made. Unfortunately, the end-quench test, though practical, can do very little toward improving the metallurgists&apos; way of thinking about transformation. These two metallurgical tools, dealing with precisely the same phenomenon, should be very closely associated in metallurgists&apos; minds. Actually, they are frequently pushed into separate mental corners and considered as being more or less distinct and unrelated. The reason for this is that no strong connecting link between them has been developed. An attempt is sometimes made to relate these two tools by projecting the critical cooling rate on the isothermal transformation plot as illustrated in Fig. I. The critical cooling rate is considered as a constant rate-though in practical applications, cooling rates are never constant—and this constant cooling rate is given uniform significance from the Ae temperature down to the temperature of initial transformation. A little thought indicates the errors of such a procedure. Certainly the time interval spent just below point A of Fig. I cannot be as effective in promoting nucleation as is the time interval spent just above point B. Yet the procedure represented in Fig. I considers all the time spent between temperatures A and B to be just as effective in promoting nucleation as though all the time were spent at temperature B. Furthermore, change the shape of the isothermal curve between points B and C in any way desired, and the required critical cooling rate is not changed one iota. This cannot possibly be true. Such a way of thinking about critical cooling rates not only is incapable of giving any results that are quantitatively satisfactory but is likely to give very misleading qualitative results.

Jan 1, 1947

By John Johnston

When I was honored by being invited to give the Howe Memorial Lecture, I decided to read Howe&apos;s book, "The Metallography of Steel and Cast Iron," published in I9I6—that is, about 25 years ago—in search of a text. I found the book written in fine, clear, attractive, yet precise style, as I expected, knowing that his father— Dr. Samuel Gridley Howe, his mother— Julia Ward Howe, and all of his four brothers and sisters had lived in a New England literary atmosphere and had written books. This leads me to suggest that many authors of metallurgical papers and books could well study Howe&apos;s writings with a view to the improvement of their own. I failed to find a specific text, but did find a subject, for in reading his book I was struck by the few instances in which time is considered explicitly as a factor in the phenomena examined, and by the fact that many of the hottest arguments would have been settled had time been taken properly into account. Indeed, Howe hardly mentions time except in a rather incidental way, as in a few references to lag; for instance: The lowering of temperature at which the transformation occurs by rapid cooling . . . is a phenomenon of undercooling or lag. It is in part explained by the fact that the transformation itself is a time-consuming reaction which, setting in during a rapid fall of temperature, is naturally protracted till the temperature has sunk far below that at which it is due. He does discuss, quite fully, the iron-clrbon equilibrium diagram, as known at that time, introducing it by stating: As he is a reasonable man who is not deterred from using a hand truck for moving his trunk by the consideration that he has thus to move a trunk plus a truck, so am I reasonable in putting into your hands this useful, indeed indispensable. tool for mastering the ABC of iron metallurgy. Somewhat later, in introducing a discussion of the phase rule, which "it would be hardly proper to pass ... by without an attempt to outline its meaning," for "a clear exposition of its applicability or jurisdiction is needed to restrain the half-initiated from misusing it and the uninitiated from being misled by these misuses," he writes—and I quote his statement because we cannot properly discuss the influence of time on a process until we know the state of equilibrium which would ultimately be reached by the system under consideration: It is a most remarkable and valuable generalization, its conceptions help greatly toward getting a broad outlook on metallography, but its misconception has brought out a flood of obscuring writings. it tells us about the constitution towards which alloys tend, that which they reach when equilibrium is complete, when all tendencies have corrected themselves and have been complied with completely. Its application, in absence of true equilibrium, is like determining density with a telescope or even with a tuning fork; it is like the mad tea party at which the butter put into the works of the watch was the best butter. If the reader learns no more than to beware of attempts to dccipher the conditions of inequilibrium by a law which touches only the conditions of exact

Jan 1, 1942

By C. R. St. John, R. W. Lindsay, Charles R. Austin

Many of the factors influencing the creep behavior of ferrous alloys have been investigated and reported upon in the literature, including such variables as grain size, steelmaking practice, nature and stability of the microstructure, and the effect of alloying elements in steels. However, with respect to the latter, the microstructures involved are usually heterogeneous and as a result the effect of the addition is related to its effects on the various phases present in the microstructure. In the instances where this structure consists of ferrite and carbide, the behavior of the alloy addition will be related to its action in strengthening ferrite and in opposing temperature softening of ferrite as well as coalescence of carbide. The present paper is the third in a series comprising a comprehensive review of investigations on the properties of iron binary alloys.l,2 Its purpose is to describe the results of isolating one microstructural phase, namely ferrite, and studying its creep characteristics in both the unalloyed and alloyed conditions. This should aid in establishing to a large degree the importance of ferrite in the creep behavior of steels consisting of the previously mentioned ferrite-carbide aggregate. In view of the fact that the present investigation deals only with the effects of silicon, manganese, chromium, molybdenum, nickel, and cobalt, and to a certain extent with the effects of carbon, the review of previous literature will be confined to these elements. Practically no references were encountered dealing with the influence of these elements on the creep characteristics of the isolated phase. However, various contributions have dealt with the creep behavior of low-carbon steels alloyed with the elements under consideration. A particularly concise review in this respect is given by Bullens (Battelle)= and much of this material has been drawn upon. The definite improvement in creep resistance and high-temperature strength conferred by molybdenum is well known. Published suggestions by the A.S.M.E.4 permit of an increase of some 2000 to 5000 lb. per sq. in. in permissible design loads over a temperature range from 650" to IOOO °F. as a consequence of additions of 0.40 to 0.60 per cent of this element in carbon steels of the order of 0.25 to 0.35 per cent carbon content. Babcock and Wilcox Tube CO.5 has published data showing the pronounced increase in stress necessary to cause one per cent creep per 10,000 hr. when additions of 0.5 or I per cent molybdenum are made to a plain carbon steel. These data apply to temperatures over a range from 800° to1000°F. 4

Jan 1, 1945

By M. R. Tek, M. L. Katz

The flow of fluids in stratified porous systems, in which adjacent layers of the system are in communication over part or all of their common interface, in many instances involves crossflow between layers. A theoretical study has been made of the unsteady-state flow of slightly compressible fluids during depletion of bounded stratified porous systems. Consideration has been restricted to single-phase flow, with negligible capillary and gravity effects. Analytical expressions have been derived for pressure distribution and for (luxes at the producing face in two-layer systems with complete fluid communication between layers. These expressions occur in the form of double Fourier and Fourier-Bessel series. The method of extending the solution to any number of layers is demonstrated by deriving the equation for pressure distribution in a three-layer system. On the basis of the exact results for two-layer systems, certain generalizations regarding the behavior of stratified systems in general are presented. The performance of stratified systems, in terms of cumulative flux as a function of time, is shown to lie at all times between bounds established from single-layer theory. The upper bound is given by treating the system as a single layer with arithmetic average physical properties. The corresponding lower bound is the summation of the fluxes from each layer as treated individually. Variation in performance of stratified systems between the upper and lower bounds is determined by the extent to which crossflow occurs in the system. The principal parameters affecting the amount of crossflow are the vertical permeability of the system, the ratio of system thickness to "radius of drainage" and, for radial systems, the ratio of system thickness to interior radius. At very early times, the system performance is near the lower bound. As time and the radius of drainage increase, the per- formance tends toward the upper bound. INTRODUCTION One of the principal problems confronting the reservoir engineer today is the incorporation of the effect of reservoir heterogeneity into predictions of reservoir performance. The first part of this problem is the characterization of the actual reservoir heterogeneity in a mathematically useful manner.1, 2 It is then necessary to calculate the effect of this heterogeneity on the system performance. It is frequently possible to estimate this effect by comparison with the known behavior of an idealized system. One such idealized system is the stratified or "layer-cake" model. Many studies have been made of the behavior of stratified systems, from both a theoretical and experimental standpoint. The great majority of the theoretical studies have been concerned with systems of separated layers, with no fluid crossflow. Among the more noteworthy of such theoretical papers is that recently published by Lefkovits, et al,3 in which a comprehensive analysis was presented for the behavior of bounded stratified systems which are unconnected except at the wellbore. Three recent references have dealt with stratified systems including the effect of crossflow. Jacquard4 has presented mathematical derivations pertaining to depletion of two layer systems producing at constant rate. A doctoral dissertation by Katz5 contains analytical solutions and tables of results for pressure distribution and fluid flux during constant-terminal-pressure depletion of two-layer and three-layer systems with crossflow, together with tables of eigenvalues necessary in the computations. The dissertation also presents results from experimental studies of stratified systems using a heat-transfer analog model. This paper is largely based on the material in this dissertation. A third paper has been presented by Russell and Prats6 since completion of the work resented herein, containing mathematical derivations for and discussion of the behavior

By George M. Enos, Robert J. Anderson

This paper gives a summary of tests made on the accelerated electrolytic corrosion of the tin brass, 70:29:1 copper-zinc-tin (admiralty metal), of different grain sixes in various electrolytes. There has been great difference of opinion as to the effect of grain size on the corrosion rate of brass, particularly in condenser-tube practice, but so far as is known no information has been published on the subject. It has been assumed, on the basis of the amorphous-cement theory, that fine-grained brass would corrode more rapidly than coarse-grained because the amorphous phase is more soluble than the crystalline and there is more cement per unit area exposed in the fine-grained material. In previous work on the corrosion of metals and alloys in acid mine waters from coal mines,1,2 it was found that the grain size, within a restricted range, had practically no effect on the corrosion of the brass 70:29:1 copper-zinc-tin: In the tests made, samples of three grain sizes were included; viz., 0.025, 0.035, and 0.075 mm. diameter (1600, 817, and 177 gr. per sq. mm., respectively), and the average losses on exposure to the most acid of three waters were 7.07, 6.80, and 6.72 mg. per sq. cm. per day (24 hr.), respectively. No distinguishing features were observed on microscopic examination of the corroded samples. In two other mine waters, the corrosion losses were substantially the same for the respective samples. These tests were -incidental to other tests and were not sufficiently comprehensive to warrant drawing definite conclusions. In further work with the accelerated electrolytic corrosion test, as developed recently in the Bureau of Mines, tests were made

Jan 1, 1924

By N. P. Goss

Asterism appearing in X-ray Laue diagrams is an extremely sensitive index of changes in the internal structures of individual grains of polycrystalline metals. It indicates the existence of various forms of subboundary structure or subdivision within the grain. The present viewpoint is that the grain is made up of lattice blocks having substantially the same size and shape.l-4 When these blocks all assume exactly the same orientation, the crystal is perfect and asterism is absent. Cleaves and Thompson5 observed that the hardness of iron is virtually constant over a range of grain sizes. It is quite possible that the subboundary structure caused this, and that the latter is just as important as grain size itself. While the experiments reported here are not conclusive, they do support this viewpoint. Metals can, under certain conditions, be prepared entirely free from asterism, but this preparation does not necessarily require long heating or slow cooling, as will be shown here. In this paper a distinction is made between mosaic and distorted grain structures but the difference is only a matter of degree. In a previous paper9 it was shown that the grains can become distorted even during heat-treatment. The block structure exists inherently, even in a perfect crystal; the size and shape of these crystallites, or lattice blocks, varies, depending upon a number of factors. Goetz, for example: has shown that a metal before crystallizing from the molten state must go through a paracrystalline phase with oriented groups of atoms about 10-l4 to 10-l5 c.c., or 10-15 cm. in size. These crystallites, or blocks, appear to survive the most drastic cold-working, for it has been shown, and more elaborately by Wood&apos;s recent work," that cold-working cannot reduce the size of these crystallites smaller than of the order 10-5 cm. The interesting correlation brought out by the experiments of Goetz and Wood is that the block size after severe cold-working is of the same order of magnitude as the groups that formed in the metal just before crystallizing from the molten state. The work of Ewald and Rennenger17 and the now classical experiments of Darwin and James12,13 all strongly suggest the existence of a periodic structure of crystal. lites smaller than the grain itself. Related to this effect is the appearance of veinlike markings in the microstructures. Ammer-man and Kornfeld,16 in their experiments, did not observe any evidence of veining in specimens of alpha iron annealed below A3 and believed that veining was not due to impurities in the iron, as Northcott16 suggested; veining was observed by them only in specimens annealed above A3. Hanemann,16 Schrader and Tangerding found that annealing in hydrogen did not diminish veining and so it could not be caused by oxides. They concluded that veining was due to a slight difference in the orientation of ferrite lattice blocks. This viewpoint is well supported by the evidence presented here.

Jan 1, 1941

By T. Prof. Ph. D. Egleston

(Read at the Amenia Meeting, October, 1877.) THE copper-bearing rocks of Lake Superior are composed of a series of metamorphic rocks, comprised under the names of amygdaloid and conglomerate, in which the copper and silver found with them are pseudomorphs. These rocks, generally, have well-defined walls which cause them to separate easily. Generally, the country rock is sterile, but it occasionally rises into the copper-bearing rock, and then carries copper. Usually, the amygdaloids carry copper, and the greenstones or melaphyres which encase them do not. There is a very generally received opinion that the copper in these beds occurs in shoots. This does not appear to be proved, though the opinion seems to have some foundation from the experience of the Calumet & Hecla Mine, where a body of poor rock has been left, which, on the mine map, shows a general direction. The theory may be true of that individual mine, but too little work has been done in the other mines to draw any decided conclusion. The copper is very unequally disseminated in the rock, if any given piece be taken as an example, but, if the whole copper-bearing series be considered, its distribution is uniform. It may prove that there are certain directions in which the copper has been deposited more abundantly than in others, and these may be found to correspond with certain geological causes, but up to the present time the knowledge gained is not sufficient to warrant any general conclusion. These rocks are supplemented by a series of true fissure veins, of which there are several systems, making the amount of native copper very large. Unfortunately, except in the fissure veins, known as "mass-mines," the copper is so scattered through the rock, and is in such a fine state of division, that, although it is not always difficult to mine, it is always difficult to dress it sufficiently too make it pay. The metal is so uniformly distributed through these copper-bearing rocks that detached pieces, called " float," are found in digging on almost any land in the country. These pieces vary from very small fragments, weighing not more than a few ounces,, up to many pounds. III one instance, in making an excavation for a cellar of a

Jan 1, 1878

By A. B. Kinzel, Walter Crafts

Inclusions of nonmetallic matter have long been recognized as objectionable in steel. A complete theory of the effect of inclusions, which is consistent with that held today, was outlined in Howe&apos;s early work on the metallurgy of iron and steel. This, by analogy with wrought iron, assumes that the observed difference in properties between specimens with and across the direction of rolling is due to slag enclosures. The fact that wrought iron shatters in ballistic test is taken as an indication of the effect of inclusions on the resistance to&apos;shock. Since that time, the development of the metallurgical microscope has shown the discrete nonmetallic inclusions in the iron matrix. Better resolution has brought out the great number of inclusions, and the availability of good microscopes in steel mills and laboratories has constantly drawn more attention to these inclusions. This recent emphasis on inclusions has resulted in studies as to their nature, mode of formation and methods of elimination, such as the work of Wohrman, Dickenson, Herty and Schenk. In addition to the published works, many investigations which have not been published have been carried out by private laboratories and have resulted in the application of specifications intended to limit inclusions in many qualities of steel. Neverthless, a clear understanding of the quantitative effect of inclusions on the physical properties of steel has been lacking. It is the specific purpose of this study to determine the quantitative effect of inclusions on the physical properties of steel that determine its behavior under dynamic stress. The study has shown that a quantitative relation between counted inclusions and impact strength does exist in normalized steels, but that factors other than readily visible inclusions are equally important. Furthermore, the present commercial rating of inclusions is unreliable with respect to counted inclusions or dynamic tests, and this study indicates that the tensile-impact test is more reliable as a measure of quality. General Scheme The general plan of the study follows: (1) To develop or establish a satisfactory measure of dynamic strength; (2) to develop or establish a

Jan 1, 1931

By J. Nutting, D. H. Kirkwood

The oxidation of lead sulfide in air between 200° and 350°C has been investigated by electron diffraction from thick sulfide films and from galena surfnces. It has been demonstrated that sulfate is the stable reaction product up to 570°C. Sulfate is HAGIHARA has investigated&apos; single crystals of galena roasted in air by the reflection electron-diffraction technique, which owing to the very limited penetration of the beam into the crystal gives information of the nature of the surface only. He has shown that up to 280°C the first oxidation product is lead sulfate, followed by lead mono-oxysulfate (PbO . PbS04). At longer times and higher temperatures more complex patterns appeared which could not be analyzed. All of these patterns were of streaks or spots arising from crystals oriented on the galena surface, and it is probable that these crystals are lead compounds whose structures have not been determined, such as the other oxysulfates (2Pb0 • PbS04 and 4Pb0 . PbS04) or a number of oxides. Certain lead sulfide films, formed chemically, give ring patterns in transmission electron diffraction2 because they are polycrystalline, and should also give ring patterns of the products after oxidation. It was thought that a diffraction study would reveal the sequence of phases produced in the reactions at different temperatures, since X-ray powder patterns are available for many lead compounds. PREPARATION OF FILMS The films were prepared by passing H2S over a saturated solution of lead nitrate in water. Once a silvery film had formed on the solution surface, no further thickening was apparent. The films were transferred by a gauze to a bath of distilled water for washing and pieces of film were caught on small discs on which they were dried. The discs were formed initially on galena up to temperatures of 300°C, followed by oxide and oxysulfates in turn at longer times. The appearance of- these phases is believed to result from an inadequate rate of supply of sulfur to the top surface 01. the crystal. standard Siemens mounts, made of platinum alloy, and had seven 20-p apertures drilled through them. The parts of the film which had dried onto the disc surface were light blue in color, which is the interference color of a film about 600A in thickness. A strong pattern of lead sulfide was obtained in transmission electron diffraction through the apertures but slight broadening indicated a crystallite size of around 200A. Tilting a sulfide film in the beam produced arcing of the rings, increasing the intensities of the (Ill), (3111, and (222) rings and reducing (200) and (220). This arises from preferred orientation in the film, a [loo] direction of the crystallites being normal to the plane of the film. These specimens were oxidized in an oven maintained at the required temperature. The reported times include that taken to heat the film to the reaction temperature. STABLE PHASES FORMED IN OXIDATION The conditions in which various oxidation products of lead sulfide are stable have been considered by the authors in a previous paper.3 It was shown that in a normal atmosphere, taken as containing lo-&apos; atm of SOs, lead sulfate would be stable up lo about 570°C. This was confirmed by oxidizing thin films of sulfide for several days, and the analysis of the transmission-diffraction pattern is given in Table 1. The fit with the patt$rn from X-rays is good, except for the missing 3.62A ring. Some disagreement in intensities of reflections given by X-rays and electrons is to be expected. Up to 570°C a spotty pattern of sulfate was still obtained, indicating grain growth, but above this temperature the film disintegrated. Probably this is associated with the decomposition to PbO . PbS04. It needs to be emphasized that the atmosphere

Jan 1, 1965

By Noah Fields Drake

During July and August, 1899, the writer took advantage of an opportunity of going to Shansi to gather some information concerning the geology and value of the already famous coalfields of that province. The long journey, mainly on slow river-boats, and the limited time at command, allowed only about ten days of work to be done in the coal-fields around Tsê Chou. The geologic structure and the rock-formations were found to be simple and quite regular, so that in that time the accompanying sketch-map (Pig. 1) was made, and a fairly good idea of the distribution of the coal and general geologic features was obtained. The map was made by measuring a base-line about three-quarters of a mile long, triangulating for principal points over the field, and filling in the details by rapid sketches. The few elevations marked on the map were taken with an aneroid barometer. Only a few of the great number of towns and villages that are within this densely populated area are shown; and the coal-mines indicated are not the only ones within the area, but the ones where most of the following information about the coal was obtained. The value of this coal-field was first clearly set before the scientific and commercial world by Baron von Richthofen,* who made a geologic reconnaissance of Shansi in 1870. Since that time the hostile attitude of the Chinese government and people towards foreigners and their enterprises has kept the coal-fields from being developed. But the last few years of rapid change in the conditions of China have at last apparently opened a way for the exploitation of this coal-field. The Peking syndicate, a joint English-Italian company, now has concessions from

Jan 1, 1901