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By Jack A. Crichton, Henry J. Gruy

This paper discusses methods used in the estimation of natural gas reserves and the general conditions under which the various methods are applicable. The factors used in estimating natural gas reserves are reviewed. Errors which have been found to occur frequently are listed. Introduction The estimation of natural gas reserves has become of paramount interest because of the increasing importance of gas in the nation's economy. Gas is a most desirable fuel, a fact substantiated by the continued rise in the market demand. In addition, new uses for gas are being developed by the chemical, plastic, and associated industries, and plants are being built to make gasoline from natural gas. These are a few of the factors contributing to the importance of the nation's natural gas reserves. With the increased importance of gas there is an increase in the need for reliable estimates of the magnitude and availability of natural gas reserves. These estimates are being used currently: (I) to determine which fields contain sufficient available reserves to justify the construction of pipe-line outlets to serve particular markets; (2) to design pipe lines necessary to serve those fields adequately;] (3) to determine the location of industrial and chemical plants; (4) to finance the development of gas properties, and the construction of gas pipe lines; (5) to determine fair and adequate depletion allowances and depreciation rates; (6) to justify applications for gas pipe lines before various regulatory bodies; (7) to determine the number of wells required to exploit the reserves most economically; (8) to aid in establishing values for the purchase or sale of gas properties, and for purposes of inheritance taxes; (9) to determine equities under unitized operations; (10) to provide a basis for calculating the economics of gas-cycling operations. History or Estimation of Natural Gas Reserves The natural gas industry in the United States had its beginning during 1826 when natural gas was used for lighting the city of Fredonia, N. Y. The first natural gas pipe line was a 25-mi]le wooden line constructed from hollowed logs, connecting West Bloomfield and Rochester, N. Y. There is no record of an attempt to estimate the gas reserve at West Bloomfield but an attempt was made to determine the capacity of the well by measuring the time required to 611 a large balloon. One of the earlier publications concerning estimation of natural gas reserves is the "Manual for the Oil and Gas Industry," published by the Treasury Department, United States Internal Revenue, in i9i9. The following methods of computing "gas depletion" are listed: (I) production decline of the gas well or property; (2) decline in open-flow capacity; (3) comparison with the life history of similar wells or properties, particularly those exhausted Art

Jan 1, 1949

By Brandon H. Grove

In Austria's only producing field, at Zistersdorf, Erdoel Produktions-gesellschaft completed a single new producer, its well Gosting 6 coming in early in October for an average production of about 15 tons daily. For further testing within the proved part of the field this company's Gosting 7 was at the close of the year drilling in Pannonian strata at 760 m., and its Gosting 8 was rigging up. Outside of the proved area of the Zistersdorf field two further tests located on the Steinberg dome failed to find production in the known oil-bearing strata of the Sarmatian, and were deepened as wildcats into the Cretaceous Flysch. The first of these, Neusiedel 1, about one kilometer north of the known producing area, found oil in the Flysch beds at a depth of 1290 m. for an initial production of about 10 tons per day. The second test, Windisch Baumgarten la, is an old well previously considered a failure, which when deepened achieved a production of about 5 tons per day in the Flysch Inoceramus beds at 985 m. Neither of the foregoing wells is producing from a stratigraphically definable horizon, oil accumulation in the Flysch of this area being apparently controlled by tectonic breccias or related crevices.

Jan 1, 1937

By Shiou-Chuan Sun

THIS paper presents the design and operation of a frothmeter capable of measuring the frothing characteristics of pine oils and other frothing reagents. The experimental data show that the froth-ability of pine oil is governed by: 1—rate of aeration, 2—time of aeration, 3—height of liquid column, 4—chemical composition of pine oil, 5—pH value of solution, 6—temperature of solution, and 7—concentration of pine oil in solution. The effect of mineral particles on the behavior of froth also was studied, and the results can be found in a separate paper.' The results also show that the relative froth-abilities of pine oils in the frothmeter generally correlate with those in actual flotation, provided that other factors are kept constant. In addition to pine oils, the other well-established flotation frothers were tested, and the results are included. In this paper, compressed air frothing is the frothing process performed by means of purified compressed air, whereas sucked air frothing is the frothing process accomplished by purified air sucked into the glass cylinder by a vacuum system. The term vacuum frothing denotes that froth was formed by degassing of the air-saturated liquid under a closed vacuum system. Apparatus The frothmeter, shown in Fig. 1, is capable of re-producibly measuring the volume and persistence of froth as well as the volume of air bubbles entrapped in the liquid and is capable of being used for compressed air frothing, sucked air frothing, and vacuum frothing. Fig. la shows that for compressed air frothing, the apparatus consists of an airflow regulating system, 1-3; a purifying and drying system, 4-8; a standardized flowmeter to measure the rate of airflow from zero to 500 cc per sec, 9; and a graduated glass cylinder, 13; equipped with an air regulating stopcock, 10; an air chamber, 11; and a fritted glass disk to produce froth, 12. The fritted glass disk, 5 cm in diam and 0.3 cm thick, has an average pore diameter of 85 to 145 microns. The pyrex glass cylinder has a uniform ID of 5.588 cm and an effective height of 63 cm. The inside cross-sectional area of the glass cylinder was calculated to be 24.53 sq cm, or 3.8 sq in. For sucked air frothing, Fig. lb shows that the apparatus for compressed air frothing is used again, with the following modifications: 1—compressed air and its regulating system, 1-3, are eliminated; and 2—a vacuum system, 16, equipped with a vapor trap, 15, and a vacuum manometer, 17, is added. The vacuum system can be either a water aspirator or a laboratory vacuum pump. Any desired rate of airflow can be drawn into the glass cylinder, 13, by adjusting the opening of the air regulating stopcock, 10. The sucked air stream is cleaned by the purifying and drying system, 4-8, before entering the glass cylinder, 13. When this setup is used for vacuum frothing, the air regulating stopcock is closed. The frothmeter has been used for almost 3 years and has proved to give reproducible results, as illustrated in Table I. With a magnifying glass and suitable illumination, the frothmeter also can be used to study the attachment of air bubbles to coarse mineral particles.' Experimental Procedures Except where otherwise stated, the data presented were established by means of the compressed air method. The volume and persistence of froth were recorded respectively at the end of 4 and 6 min of aeration at a constant rate of airflow of 29.3 cc per sec, which is equivalent to 71.6 cc per sq cm per min, or 462.6 cc per sq in. per min. The aqueous solution for each test, containing 1000 cc of distilled water and 19.2 ± 0.5 mg frothing reagent, was adjusted to a pH of 6.9 0.2. The volume of froth is expressed as cubic centimeter per square centimeter and is equivalent to the height of the froth column (the distance between the bottom and the meniscus of the froth). The volume of froth was obtained by multiplying the height of froth by the cross-sectional area of the glass cylinder, 24.53 sq cm. Before each test, the glass cylinder, 13, was cleaned thoroughly with jets of tap water, ethyl alcohol, tap water, cleaning solution, tap water, and finally distilled water. The cylinder with stopcock,

Jan 1, 1953

By Shiou-Chuan Sun

THIS paper presents the design and operation of a frothmeter capable of measuring the frothing characteristics of pine oils and other frothing reagents. The experimental data show that the froth-ability of pine oil is governed by: 1—rate of aeration, 2—time of aeration, 3—height of liquid column, 4—chemical composition of pine oil, 5—pH value of solution, 6—temperature of solution, and 7—concentration of pine oil in solution. The effect of mineral particles on the behavior of froth also was studied, and the results can be found in a separate paper.' The results also show that the relative froth-abilities of pine oils in the frothmeter generally correlate with those in actual flotation, provided that other factors are kept constant. In addition to pine oils, the other well-established flotation frothers were tested, and the results are included. In this paper, compressed air frothing is the frothing process performed by means of purified compressed air, whereas sucked air frothing is the frothing process accomplished by purified air sucked into the glass cylinder by a vacuum system. The term vacuum frothing denotes that froth was formed by degassing of the air-saturated liquid under a closed vacuum system. Apparatus The frothmeter, shown in Fig. 1, is capable of re-producibly measuring the volume and persistence of froth as well as the volume of air bubbles entrapped in the liquid and is capable of being used for compressed air frothing, sucked air frothing, and vacuum frothing. Fig. la shows that for compressed air frothing, the apparatus consists of an airflow regulating system, 1-3; a purifying and drying system, 4-8; a standardized flowmeter to measure the rate of airflow from zero to 500 cc per sec, 9; and a graduated glass cylinder, 13; equipped with an air regulating stopcock, 10; an air chamber, 11; and a fritted glass disk to produce froth, 12. The fritted glass disk, 5 cm in diam and 0.3 cm thick, has an average pore diameter of 85 to 145 microns. The pyrex glass cylinder has a uniform ID of 5.588 cm and an effective height of 63 cm. The inside cross-sectional area of the glass cylinder was calculated to be 24.53 sq cm, or 3.8 sq in. For sucked air frothing, Fig. lb shows that the apparatus for compressed air frothing is used again, with the following modifications: 1—compressed air and its regulating system, 1-3, are eliminated; and 2—a vacuum system, 16, equipped with a vapor trap, 15, and a vacuum manometer, 17, is added. The vacuum system can be either a water aspirator or a laboratory vacuum pump. Any desired rate of airflow can be drawn into the glass cylinder, 13, by adjusting the opening of the air regulating stopcock, 10. The sucked air stream is cleaned by the purifying and drying system, 4-8, before entering the glass cylinder, 13. When this setup is used for vacuum frothing, the air regulating stopcock is closed. The frothmeter has been used for almost 3 years and has proved to give reproducible results, as illustrated in Table I. With a magnifying glass and suitable illumination, the frothmeter also can be used to study the attachment of air bubbles to coarse mineral particles.' Experimental Procedures Except where otherwise stated, the data presented were established by means of the compressed air method. The volume and persistence of froth were recorded respectively at the end of 4 and 6 min of aeration at a constant rate of airflow of 29.3 cc per sec, which is equivalent to 71.6 cc per sq cm per min, or 462.6 cc per sq in. per min. The aqueous solution for each test, containing 1000 cc of distilled water and 19.2 ± 0.5 mg frothing reagent, was adjusted to a pH of 6.9 0.2. The volume of froth is expressed as cubic centimeter per square centimeter and is equivalent to the height of the froth column (the distance between the bottom and the meniscus of the froth). The volume of froth was obtained by multiplying the height of froth by the cross-sectional area of the glass cylinder, 24.53 sq cm. Before each test, the glass cylinder, 13, was cleaned thoroughly with jets of tap water, ethyl alcohol, tap water, cleaning solution, tap water, and finally distilled water. The cylinder with stopcock,

Jan 1, 1953

By M. Gangal, B. Paul

It may be seen from Maurer's survey (Maurer,l 1966) that most of the common methods used in rock drilling today depend upon mechanical loading of the rock. In order to predict the behavior of rock under an imposed system of stresses, it is necessary to have a valid criterion which delineates those combinations of stress which cause macroscopic rock failure from those which do not. Admittedly, the conditions under which brittle materials fracture depend very much upon statistically variable local effects such as inclusions, grain boundaries, minute imperfections, etc. However, it is extremely desirable to be able to predict fracture under complex states of stress by means of a stress-criterion of failure, where, for a given material, the effects of the other variables mentioned are incorporated into a small number of experimentally observable parameters. One of the most successful of these "macroscopic stress criteria" has been the Coulomb-Mohr theory 2,3 (also see Jaeger 4 and Terzaghi 5), modified by the addition of tension cutoffs (Paul 6). At first thought it might seem rather odd that a macroscopic theory is capable of predicting fractures which originate at highly localized random imperfections at an atomic level (or more likely at the level of individual mineral grains in rocks). However, Griffith7 showed that fractures originating near the tips of randomly oriented elliptical cracks lead to the macroscopic stress criterion of failure indicated in Fig. 1 (a). Fig. I (a) is to be interpreted in the following way: P and Q represent the maxi mum and minimum principal stresses (compression is considered positive) in a macroscopically isotropic body; fracture will not occur for any combination of principal stresses lying within the 'fracture curve' shown, but

Jan 1, 1967

By George J. Bancroft

INTRODUCTION. IT is unnecessary to repeat here the contents of many valuable contributions to this subject which have appeared in the Transactions and in the publications of the U. S. Geological Survey. As a basis for the further suggestions of this paper, the following are the most important: 1. The investigation of J. R. Don,1 showing the gold of certain Australasian veins to have been deposited by ascending solutions, and not by lateral secretion. 2. The theory of Prof. Posepny,2 distinguishing the vadose from the deep circulation, and ascribing the origin of certain classes of ore-deposits to ascending solutions of the latter class. 3. The theory of Prof. Van Hise,3 as to the underground circulation and the primary enrichment of veins thereby. 4. The paper of Prof. J. F. Kemp,4 showing that ore-deposits are largely the products of " expiring vulcanism." Many of Prof. Kemp's, ideas have been widely adopted by mining men. 5. The theory of secondary enrichment, so lucidly expounded by Mr. S. F. Emmons.5 This theory, dealing with, the rearrangement of ore-bodies after primary mineralization, has been generally adopted, and seems to me to have been as completely proved as the nature of the case permits. There are two facts which I think should be constantly borne in mind in formulating a theory of the genesis of ore-

Jan 1, 1913

By H. H. Hausner, H. S. Kalish

M. Hansen—This paper certainly is an interesting study. Although I have not had too much experience in the powder metallurgical methods of studying phase equilibria, I would like to say the following concerning the interpretations of the results obtained: 1. The existence of a zirconium-rich eutectic having a melting point close to 950°C and containing approximately 5 pct beryllium is well established. 2. Undoubtedly sintering of the original compacts (i.e., without repressing and resintering at 1350°C) resulted in a condition being far from equilibrium, even in the low-melting point zircon-rich region where undissolved zirconium particles have been observed. This means that only partial reaction between the component powders has taken place. 3. In preparing and handling powder mixtures for pressing and sintering, we have found that with powders differing considerably in density, and also in particle size, separation in layers of different composition may occur. This means that a concentration gradient would exist within such samples. This phenomenon may, at least to some extent, account for the difference in microstructure of the top and bottom regions of some of the sintered samples. If this is the case, density figures for some of the nominal compositions would not represent actual densities of those mixtures. 4. Fig. 1 shows that the low densities of mixtures with 40 and 60 pct beryllium sintered at 1350°C are changed to much higher densities if the products sintered at 1100°C are repressed and resintered at 1350°C, whereby an approach toward equilibrium takes place. This would mean that the low density and growth in volume is due to nonequilibrium conditions. If this is true, would it be justified, then, to conclude that "the remarkable growth of the alloys in the vicinity of 40 to 60 pct Be indicates the formation of a high-melting point phase, probably accompanied by a considerable change in volume due to a large alteration of the crystal structure from that of the original compounds"? If some compound formation has taken place already during the first sintering at 950" to 1350°C, more compound would be formed by repressing and re-sintering of the 1100" samples. This treatment, however, results in higher, rather than lower, densities. In general, the density-composition curve of alloy systems containing one or more intermediate phases is characterized by a more or less defined contraction (decrease in specific volume, increase in density) over the "theoretical" density. Does not discrepancy exist between the two statements that "growth of the alloy indicates the formation of a high-melting phase . . ." and "even at 1350°C, no indications of sintering have been observed"? 5. I am not sure that the explanation given for the fact that fig. 4 did not reveal as much eutectic as the top portions of the mixture with 2 pct Be, is correct. The density of the melt containing only 5 pct Be or even perhaps less, is not too much different from that of the nominal composition. The reason might be also that there was already some separation of the components in the pressed compact. 6. I do not understand why the microstructure of the bottom regions of the compact with 5 pct Be (fig. 6) is so different from that of the top regions (fig. 5). The compact was melted on sintering at 1100°C. Its composition lies close to the eutectic point. There should be at least some lamellar structure in the bottom regions too; otherwise, the composition of top and bottom must have been very different after sintering, because the eutectic is said to extend as far as the composition ZrBe2. In case the white and gray areas of fig. 6 are both gamma, and the black areas undissolved zirconium, this composition would be close to the phase coexisting with zirconium, that is, ZrBe2, according to the hypothetical diagram, or a compound richer in zirconium. 7. Figs. 9 and 10 are not mentioned in the text. 8. The great difference in microstructure of the composition 20 pct Be of figs. 8 and 14 on one side and fig. 15 on the other side proves that sintering at 950" and 1100°C results only in partial reaction of the powers. 9. The mixture with 60 pct Be (fig. 19) seems to consist of two phases, rather than one phase, one interspersed in a matrix of another. 10. The statement that the eta phase "may be an intermetallic compound or the product of a peritectic or monotectic reaction" seems to be misleading, because the product of a peritectic or monotectic reaction in this region of the system must be an intermetallic compound. 11. If there is some solid solubility of Be in alpha and beta-Zr, it would be expected to be higher in beta-Zr (b.c.c.) than in alpha-Zr (h.c.p.). The temperature of the polymorphic transformation of zirconium then would be lowered, rather than increased. In accordance with this, Battelle has found that the transformation point of titanium is decreased by beryllium. 12. In case the phases present in alloys with 80, 90, and 95 pct Be are identical (which appears to be correct), it is striking that the relative amounts of both phases (eta and beryllium) are not too different within this wide range of composition. With 60 to 65 pct Be

Jan 1, 1951

By Allen J. Johnson

Anthracite coals have been divided into three groups: (I) meta-anthracite, a high-carbon coal that is usually very slow to kindle and difficult to burn, at least on conventional equipment; (2) anthracite, a high-carbon low-volatile coal of widely accepted value as both a domestic and industrial fuel; and (3) semianthracite, a coal lying between anthracite and bituminous coal in carbon and volatile content, and also, generally speaking, in burning characteristics. Anthracite Groupings The technical differentiation between these groups, as defined by the A.S.A.-A.S.T.M. Sectional Committee on the Classification of Coals, is as shown in Table I. Tables 2 and 3 show typical analyses of anthracites and semianthracites and Figs. I to 3 show graphically the range of analytical samples. Table 4 shows the commercial sizes of coals. Meta-anthracite and Graphitic Anthracite Typical analyses from virtually every field in the United States indicate that there are few if any extensive deposits of meta-anthracite. Some of the anthracites of Rhode Island contain almost negligible quantities of volatile and would thus fall into the meta-anthracite grouping on a basis of analyses alone. However, their other characteristics indicate that it is doubtful whether they should be considered as fuels at all, but rather as graphite. In fact, this material is being mined for use as foundry facings and furnace linings.4 A typical analysis of Fenners Lodge graphite,4 from Rhode Island, is: graphitic carbon, 55.9 per cent; silica (ash), 40.6; sulphur, 1.6; moisture, 1.9; volatile, o. Other Rhode Island coals possess percentages of volatile that would throw them into the normal anthracite rather than the meta-anthracite class. However, this "volatile" is nearly all noncombustible,3,4 being composed almost entirely of carbon dioxide and inert gases, therefore its definition as volatile is open to discussion, leaving the exact classification of the fuel a moot question. One factor is certain, Rhode Island coal is so different from nor-mal anthracite in both analysis and burning characteristics that it should have a

Jan 1, 1944

By Allen J. Johnson

Anthracite coals have been divided into three groups: (I) meta-anthracite, a high-carbon coal that is usually very slow to kindle and difficult to burn, at least on conventional equipment; (2) anthracite, a high-carbon low-volatile coal of widely accepted value as both a domestic and industrial fuel; and (3) semianthracite, a coal lying between anthracite and bituminous coal in carbon and volatile content, and also, generally speaking, in burning characteristics. Anthracite Groupings The technical differentiation between these groups, as defined by the A.S.A.-A.S.T.M. Sectional Committee on the Classification of Coals, is as shown in Table I. Tables 2 and 3 show typical analyses of anthracites and semianthracites and Figs. I to 3 show graphically the range of analytical samples. Table 4 shows the commercial sizes of coals. Meta-anthracite and Graphitic Anthracite Typical analyses from virtually every field in the United States indicate that there are few if any extensive deposits of meta-anthracite. Some of the anthracites of Rhode Island contain almost negligible quantities of volatile and would thus fall into the meta-anthracite grouping on a basis of analyses alone. However, their other characteristics indicate that it is doubtful whether they should be considered as fuels at all, but rather as graphite. In fact, this material is being mined for use as foundry facings and furnace linings.4 A typical analysis of Fenners Lodge graphite,4 from Rhode Island, is: graphitic carbon, 55.9 per cent; silica (ash), 40.6; sulphur, 1.6; moisture, 1.9; volatile, o. Other Rhode Island coals possess percentages of volatile that would throw them into the normal anthracite rather than the meta-anthracite class. However, this "volatile" is nearly all noncombustible,3,4 being composed almost entirely of carbon dioxide and inert gases, therefore its definition as volatile is open to discussion, leaving the exact classification of the fuel a moot question. One factor is certain, Rhode Island coal is so different from nor-mal anthracite in both analysis and burning characteristics that it should have a

Jan 1, 1944

The following table summarizes the information on the Hurghada field. which is still the major producing field in Egypt. Age of field to end of 1937. years..................... 24 Producing area for gas and oil. acres.................. 1.050 Babbels Total oil production to end of 1937................... 30.188.500 Total oil production during 1936..................... 1.219.406 Total oil production during 1937..................... 1.141.230 Average oil production per acre to end of 1937.......... 28.750 Average oil production per acre-foot to end of 1937.... 2.359 Daily average production (Nov. 1937)................ 3.162 Daily average production per well (Nov. 1937)........ 41.88 MillionB Cu. Ft. Total gas production (Aug. 1925 to end of 1937)....... 4,189 Total gas production during 1936.................... 281 Total gas production during 1937.................... 222.5 Maximum daily average in 1937 (July)............... 0.7 Number of producing wells completed to end of 1937... 97 Number of producing wells completed during 1937..... 3 Number of wells abandoned during 1937.............. 1 Producing wells at end of 1937....................... 78= Total number abandoned wella at end of 1937......... 19 Total number dry wells at end of 1937................ 20 Average depth of bottom of producing horizon, ft...... 1,720 Average depth of top of producing horizon, ft.......... 1,598 Character of oil, approximate average in 1937: gravity at 60" F., 0.900; base, mixed. Character of gas, approximate average during 1937: gallons gasoline per 1,000 cu. ft., 6.9. Producing rock (main): Nubian (?) sandstone. Cretaceous (?); character, sand rock and sandstone. 1 Figures were given in E. tons. A conversion factor of 6.98, based on 0.900 sp. gr., was used to obtain the number of barrels.—Ed. *All pumping.

Jan 1, 1938

By Zay Jeffries

OF the new production of non-ferrous metals in 1930 gold will rank first in value. We usually think of copper as the most important non-ferrous metal. The copper industry as a whole, that is, adding copper production to copper fabrication, is the largest non-ferrous metal industry. Prior to the world war; however, gold led in value of new metal produced. During the war copper passed gold in value, but gold regained its position during the 1921 depression. For the past several years copper has again passed gold, but in 1930 gold promises again to regain the lead. The gold producer has at times been called a social parasite, largely because we ' cannot eat or drink gold, or because we cannot use it for clothes or for the construction of buildings. Let us briefly examine this accusation.

Jan 1, 1930

By R. G. Davies, P. Beardmore, T. L. Johnston

The flow stress of a series of Ni-Cr-A1 alloys consisting of a dispersion of y' (based on Ni3Al) in a rnatrix of nickel-base solid solution y has been measured at temperatures up to 950°C as a fwzction of the volume fraction of y'. At high temperatures the flow stress is controlled by the amount of Y' in the alloy, i.e., the higher the volume fraction of y', the greater is the flow stress. This simple relationship is not obeyed at low temperatures in so far as a peak in the flow stress-volume fraction relation occurs at about 25 pct y'. The variation in the mechanical properlies of these alloys as a function of both temperature and volume fraction of y' has been correlated with changes in distribution of both the dislocations and y'. The results are interpreted on the basis that at low temperatures the y matrix is strengthened significantly bv the presence of a hyperfine y' precipitate due to decomposition on cooling; at high temperatures the y matrix is a single phase of low strength. It is clearly recognized that the high temperature strength of most nickel-base superalloys depends upon a dispersion of the ordered fcc phase y', based on Ni3A1, in a fcc solid solution matrix y based on nickel. Although the volume fraction of y' varies widely from about 0.2 in Nimonic 80A to about 0.6 in Mar-M200, all such nickel-base alloys manifest an unusual insensi-tivity of the flow stress with respect to temperature. In Mar-M200 for example, the 0.2 pct flow stress remains essentially constant from room temperature to 750°C. The conclusion has been drawn1 that the characteristically low temperature dependence of the flow stress of y-y' nickel-base alloys is obtained when the state of dispersion of y' is such that dislocations are forced to cut through the y' particles at the onset of yielding. When the spacing between the y' particles is so large that the flow stress is controlled by dislocation bowing between particles, then the initial flow stress decreases progressively with an increase in temperature at a rate determined by changes in elastic properties. The same conclusion is inherent in the detailed, mechanistic model of the deformation process in commercial superalloys which has been developed by Copley and ear' in which the temperature independent flow stress is attributed primarily to the contribution of the antiphase boundary energy created in the y' particles during deformation. In this theory the temperature insensitivity of the flow stress is a reflection of the constant antiphase boundary energy as a function of temperature. An important microstructural parameter that is relevant to the explanations that have been suggested' to account for the temperature insensitivity of the flow stress is the volume fraction of y'. To vary the latter to any significant extent in a given commercial alloy is clearly difficult. However, it is possible in a relatively simple Ni-Al-Cr ternary system which manifests analogous microstructures in terms of the distribution of y' in y and contains specific alloys which have flow properties that depend on temperature in a manner quite similar to their more complex commercial counterparts. Hornbogen et . have studied precipitation phenomena and deformation mechanisms in such alloys but only where the y' volume fraction was small (less than 0.2) and the y' particle size varied from less than 100A up to a maximum of -1000A. In the present study, a series of alloys was prepared in which the volume percent of y' at 900°C was varied from 0 to 100 pct with the y' particle size (of the order 0.5 p) comparable to the sizes obtained in commercial superalloys. Particular attention has been given to the relationship between variations in the volume fraction and distribution of y' and the temperature dependence of the flow stress EXPERIMENTAL TECHNIQUES The Ni-Cr-Al system was selected because it is well characterized, bears a close relationship to commercial alloys, and offers the advantage of an extra degree of freedom over a binary system. In the present investigation, a series of alloys across the tie line between NisA1 and Ni3Cr (Ni3Cr is not an in-termetallic compound, the nomenclature is only used to designate the composition) were vacuum cast. The pseudobinary6 and the composition of the alloys used are shown in Fig. 1. It is important to note that the compositions of the y phase and the y' phase in the two-phase alloys was always the same. Alloy compositions were selected from the binary diagram, Fig. 1, in order that aging at 900°C would produce from 0 (100 pct y) to 100 pct y' by volume percent. (The size of the y' particles produced during the equilibrium aging treatment increased as the volume fraction of y' increased, ranging from about 0.2 p at low volume fractions up to about 0.8 p at the highest volume fraction.) The y' phase is based on the inter-metallic compound Ni,A1 which has the fcc LIZ type superlattice structure, and chromium substitutes for aluminum in the structure. The y phase is a disordered fcc solid solution. The alloys were heat treated at 1150°C for 2 hr, air cooled to room temperature, and finally annealed for 16 hr at 900°C. The rods were then centerless ground to 0.25 in. diam and cut into compression samples 0.5 in. long. The compression tests were made on an In-stron machine at a strain rate of 7 x 10"4 sec-'. A rapid heating radiant heat furnace was used which minimized the heating and temperature stabilization time to 10 min for the highest testing temperature. All the tests were stopped after 5 pct plastic strain.

Jan 1, 1970

By C. E. Van Orstrand

AN intrusive body is a mass of igneous rock that has migrated upward, presumably from great depths. Great variations in form, composition and depth of burial occur. It is not proposed in this paper to go into all of the details of the problem. Instead, it will be assumed here that the intrusive has the form and characteristics represented in Fig. I. According to W. H. Emmons,1 minerals are not deposited in appreciable quantities below the "dead line." Important amounts of ores of virtually all metals may be found around summit cupolas, but only gold, copper and zinc (in limited quantities) are usually associated with trough cupolas. Most students of ore deposits agree that temperature changes are largely instrumental in precipitating many ores in the "hood" and that the difference in temperature between the intrusive and that of the country rock may be the chief factor in determining the mineralogy of a deposit. A problem then of some interest is to correlate the principal physical features of the intrusive with the phenomena of heat conduction as evidenced by the cooling curves and the isothermal surfaces. MATHEMATICAL THEORY In order to show the possible application of heat conduction to the interpretation of the processes of metalliferous deposition associated with intrusives, it will be assumed that the intrusive is a large parallelopiped of dimensions, 2l, 2m, 2n. The equation that represents the flow of heat from the parallelopiped into country rock (v = o, t = o), which has the same thermal properties as the intrusive, is2,3 [ ] In this equation, the origin, x = o, y = o, z = o, is at the center of the parallelopiped. 'v = temperature at point x, y, z, time t. vo = initial temperature throughout the intrusive, t = o. K = coefficient of thermal diffusivity. a, ß, ? are variables of integration. Put n = m in Eq. I, and we have [ ]

Jan 1, 1944

By R. P. Smith

The carbon content of a number of alloys ranging (before carburitation) from purified iron to purified cobalt was determined for fixed activities of carbon by equilibration with each of six CO-CO2 atmosphere at 1000°C. At fixed carbon activity, the carbon content decreases continuously with increasing cobalt content. For concentrations of 0 to 50 at. pct Co the results can be expressed by a linear interaction equation of the type In y2 = 7.76n2/(n1+n3)+ 2.30 n3/(n1+n3) where y2 is the activity coefficient of carbon (standard state such that y2— 1 as n2 — 0 in the Fe-C binary) and n1, n2, and n3 are the number of atoms of iron, carbon, and cobalt per unit weight of alloy. The results are also given in terms of the a functions. In the same concentration range, the results are in accord with the regular solution theory of Alcock and Richardson. THE carbon content of Fe-Si, Fe-Mn, and Fe-Ni alloys at fixed activities of carbon has been reported previously.'-, The present work extends R. P. SMITH, Member AIME, is Research Chemist, E. C. Bain Laboratory for Fundamental Research, United States Steel Corp., Research Center, Monroeville, Pa. these measurements to a series of Fe-Co alloys. These alloys, like the Fe-Ni alloys, are fcc ("aus-tenitic") over the entire range of composition at 1000°C. EXPERIMENTAL PROCEDURE The alloys were made from electrolytic cobalt and Plast-Iron in a small vacuum-melting furnace. A small amount of graphite was added to each melt to keep the oxygen content low. The ingots were analyzed for iron and carbon: the amount of cobalt was obtained by difference. Analysis of the top and bottom of the ingots indicated that they were uniform in alloy content. Except for the pure cobalt the ingots were hot-rolled to approximately 0.15 cm thickness, cleaned by sandblasting, then cold-rolled to about 0.045 cm. We were not successful in cold rolling the pure cobalt; therefore it was hot-rolled to the final thickness. The last traces of surface oxide were removed by acid pickel, then the samples were treated in a hydrogen-2 pct water vapor mixture at 1100°C to remove carbon and most of the oxygen. The carburizing procedure was similar to that previously described.1,2,4 The alloys in the form of strips about 1.7 cm wide, 7.5 cm long, and 0.04 cm thick, together with a similar specimen of purified iron, were equilibrated with each of six CO-CO2 mixtures of fixed composition, then quenched in the

Jan 1, 1965

By S. A. Lever, R. Hultgren

(E. R. Jette and J. R. Long presiding) M. B. BEVER*—The method re- ported in this interesting paper promises to he of fairly wide applicability. It may be expected that the solidus and liquidus lines in other low-melting alloy systems can also be determined by resistance measurements. As these alloys are especi- ally slow to reach equilibrium, a static method will improve the accuracy with which these parts of their phase diagrams can be determined. It should be noted that the sensitivity of the method for the determination of

Jan 1, 1950

By AIME AIME

THE Petroleum Division opened its proceedings on Wednesday morning, with two simultaneous sessions on engineering and economics. The first paper at the engineering session, over which A. W. Ambrose presided, was "Underground Surveys of Oil Wells," by Alexander Anderson of Los Angeles, Calif., was presented by John Suman of the Humble Oil & Refining Co., Houston, Texas. Following this, the paper of E.'H. Griswold of the Mailand Oil Co., Houston, Texas, was presented by C. V. Millikan of the Amerada Petroleum Corp., Tulsa, Oklahoma. Following the presentation of these two interesting papers a general discussion followed on the subject of "Crooked Holes." The discussion was entered into by F. H. Lahee, Sun Oil Co., Dallas, Texas;'Messrs. Bigelow of Tulsa, H. W. Hixon of New York City, Van Court Warren of Los Anyeles, Calif; H. L. Wheeler of St. Louis, Mo.; R. R. Brandenthaler, United States Bureau of Mines, Bartlesville, Okla.; H. H. Riggs, Indiana Territory Illuminating Oil Co., Bartlesville, Okla.; C. V. Millikan and John R. Suman

Jan 1, 1929

By A. E. Jenkins, L. A. Baker, N. A. Warner

Rates oj decarburization of levilated Fe-C droplets conlaining 5.5 to 0 pct C have been measured at 1660°C. Gas mixtures of 1, 10, and 100 pct 0, with helium diluenl were used at velocities of 12.5 and 62.5 cm per sec. Rates were independent of carbon concentration in the mell and in good agreement with the calculated rule of oxygen diffusion through the gas boundary layer. The effects of flow rale and total pressure are as predicled and the rates are approxitnalely 2.5 times those with CO2 as oxidant. The mass-transfer correlation used incorporaled the efject of natural convection as well as forced conrection. Graphile spheres are shown to oxidize at the same rate as Fe-C droplets under the same experimental codlions. It is concluded that, for high carbon concentrations in the melt, the rate of- decarburizalion is controlled wholly by the rate of gaseous diffusion. Rate measurements with pure CO, are reported for low carbon concentrations where CO bubbles nucleate within the droplet. Under these circumstances the decarburi-zation decreased with carbon concentration and it is proposed that carbon diffusion is significant in conlrolling the decnvburization rate. In an earlier paper1 decarburization rate measurements were reported for levitated Fe-C alloys at 1660°C but with CO2 as the oxidant. The decarburization rate was found to be independent of carbon concentration in the melt but slightly affected by total pressure. The authors were unable to explain the slight pressure effect but in all other respects the results were consistent with control by diffusion in the gas boundary layer. Subsequent work has been directed at finding the reason for the slight pressure effect and whether the kinetics with oxygen as oxidant parallel those with CO2. Recently Ito and Sano2 have shown that with water vapor-argon atmospheres the decarburization rate is gaseous diffusion controlled until an oxide film appears on the surface. In this work the melts were contained in crucibles. MASS TRANSFER IN THE GAS PHASE In the earlier analysis1 only forced-convection mass transfer was considered. Subsequent recognition of the existence of some free-convection mass transfer explained the observed small effect of total pressure on the decarburization rate. Steinberger and Treybal3 and Kinard, Manning, and Manning4 have developed correlations involving the linear addition of the contribution of radial diffusion, free and forced convection. Steinberger and Treybal&apos;s correlation was chosen as the most applicable to the present work since it correlated most of the data available in the literature and handled the low Reynolds number region exceptionally well. The correlation for (Gr&apos;Sc) < 108 is where Nu&apos; is the Nusselt number for mass transfer based upon the total surface of a sphere in an infinite medium, G&apos; is the mean Grashof number for mass transfer defined by Eq. [2], Sc is the Schmidt number (µ/pDAB)f, Re is the sphere Reynolds number (dpu,pf/µf), p is the viscosity of the gas (poise), p is the density of the gas (g cm-3), Dab is the binary diffusivity for the system A-B (sq cm sec-&apos;), dp is the sphere diameter (cm), u is the approach velocity of the gas (cm sec-I), and subscript f denotes the property value is computed at the film temperature Tf defined by Tf = +1/2(To + Tr) where To is the specimen temperature and T, is the approach gas temperature (oK). Natural convection occurs when inhomogeneities exist in gas density. These may be caused by concentration gradients, temperature gradients, or both. In the present work the temperature gradient between the sphere and the bulk gas was very large and in some cases, for example the runs with pure oxygen, the concentration gradient was also appreciable. The Grashof number defined by Mathers, Madden, and piret5 was used since it took account of both temperature and concentration gradients: where Gr&apos; is the Grashof number for mass transfer (p2fgd3|-yA-yA|/µ2f), Gr is the Grashof number for heat transfer (p2f gd3p|To - T,]/µ2fTf), Pr is the Prandtl number (cpµ/k)f, g is the acceleration due to gravity (cm sec-&apos;f, a is the concentration densification coefficient (1/p)(ap/ayA)T, yA is the mole fraction of component A at the gas-metal interface, yA is the mole fraction of component A in the bulk gas stream, cp is the heat capacity of the gas per unit mass at constant pressure (cal g-I OK-&apos;), and k is the thermal conductivity of the gas (cal cm-&apos; sec-1 OK-1). Mathers et al. tested this combined Grashof number

Jan 1, 1968

By J. A. Cordier

USINOR has conducted four blast furnace tests with formcoke made from marginal coals in the pilot plant of HBNPC ("H. B. N." process) in four different blast furnaces of various sizes and with medium and high grade burdens. The tests in which up to 30% of the blast furnace fuel burden was replaced by HBN formcoke yielded good results on furnaces ranging in hearth diameters from 5.6 to 9.5 m. The tests demonstrated that: - the slight increase of pressure drop in the stack did not prevent smooth operation at record production rates with the same blowers - the total coke rate was not significantly affected, but there was a slight increase of the calorific value of the top gas - the hot properties of the formcoke are satisfactory as seen from the samples withdrawn at the tuyeres and tapholes. At the end of the two months test on BE nº 2 of Dunkerque, the hearth was as permeable and clean as with good standard coke. Our conclusion is that HBNPC formcoke made from lean coals is an adequate substitute for conventional coke in the range of 20 to 40% replacement, which is of interest to USINOR.

Jan 1, 1977

By Sir John Cadnan

The production from the Maidan-i-Naftun area for the year ending March, 1928, was 5,340,000 tons (40,210,200 bbl.), an increase of nearly 13 per cent. over the production for the year ending in March, 1927. The production by years since the opening of the field in 1912 is given in the following table: [1 ton = 7.53 bbl.] Year Ended MaRch Tons Year Ended March Tons 1912 (7 months)............. 43,084 1920....................... 1,354,631 1913........................ 80,800 1921....................... 1,767,070 1914........................ 273,635 1922....................... 2,310,098 1915........................ 375,977 1923....................... 2,913,908 1916........................ 449,394 1924....................... 3,583,000 1917........................ 644,074 1925....................... 4,221,000 1918........................ 897,402 1926....................... 4,470,000 1919....................... 1,081,919 1927....................... 4,735,000 1928....................... 5,340,000 The actual production represents only a small proportion of the potential production. The Masjid-i-Suleiman Field The present producing unit, the Masjid-I-Suleiman, is an anticline some 20 miles in length by 4 miles in width, including three domes as so far proved. The producing horizon is a very open, dolomitic limestone, which, while showing much variation in texture and porosity, is so connected that the lowering of pressure in one section of the field quickly affects the whole area. The topography of the field is broken, with differences of well elevations of as much as 1100 ft. The depths to the limestone vary from about 800 to about 5000 ft. The closed-in pressure of the oil wells varies from zero to 50 lb. per sq. in. and that of the gas wells is about 450 Ib. Although the static oil level may be several hundred feet below ground level, in oil wells of high elevation, all the wells flow continuously or intermittently after they are once started—the majority continuously. The gas is very high in hydrogen sulfide in gas-oil wells of low pressure.

Jan 1, 1929

By Craig R. Barrett, Oleg D. Sherby

The creep characteristics of four pure metals with widely Varying stacking-fault energies (silver, copper, nickel, and aluminum) were evaluated above 0.5Tm. Creep tests were performed under conditions of constant atomic diffusivity and constant stress over the elaslic modulus. The sleady-state creep rate, Es, was found to he a funclion of the THE most common empirical representation of the steady-state creep rate, Es, at high temperatures and intermediate stresses is of the form where a is the applied stress, E is an elastic constant, A and n are constants (n is typically stacking-fault energ, y, such that Es is proportional to y3,5. In addition, it was uncovered that the primary creep strain and the strain to fracture increased with increasing y, and that the ratio of initial to steady-state creep rate decreased with increasing y. about 5), Q is the activation energy for creep (usually equal to that for self-diffusion), and kT has its usual meaning. sherbyl and McLean and ale&apos; have used this expression to correlate creep data for a number of pure metals. An interesting aspect of Eq. [I] is the absence of any dependence on the stacking-fault energy. While most creep data seem to obey the stress and temperature dependence predicted by Eq. [I], when data for several metals are put on a master plot they do not fall on a common line but form a band. The width of this band corresponds to a variation in Es of 102 to l03. sherbyl attempted to explain this band by assuming that a grain-size effect was present which led to the observed variation. On the other hand, Felt-

Jan 1, 1965