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By G. W. P. Rengstorff, L. E. Olds

High purity molybdenum ingots containing controlled amounts of a single impurity element (oxygen, nitrogen, or carbon) were prepared. These ingots were tested for ductility by bending test specimens at various temperatures. The relationship between the plastic behavior of the ingots and their chemical composition has been determined. MANY proposed applications for molybdenum require ductility at or near room temperature. At the present time, it is possible to obtain wrought molybdenum with considerable ductility only if special fabrication techniques are used to control the grain structure. Starting with are-cast or powder metallurgy ingots, the usual methods for obtaining ductility rely on fabrication procedures that result in fibered microstructures in the finished product. Recently, it has been found that the ductility of either powder metallurgy or are-cast molybdenum can be improved by uniform recrystallization of the metal to a very fine equiaxed grain structure.' The need for a fibered or a fine grained structure may limit the practical usefulness of molybdenum. For example, welding. which may be used in fabricating the metal, generally produces coarse grained structures that lead to brittleness. This applies, certainly, to currently available commercial molybdenum. Although commercial molybdenum is brittle when the grains are coarse, it has been shown experimentally that fine grained structures are not always essential for ductility. For instance, as-cast molybdenum with a coarse columnar grain structure is ductile if it is sufficiently pure.' Because high purity cast molybdenum has good ductility even when coarse grained, it is probable that the brittleness in coarse grained commercial molybdenum is caused by the impurity content of the metal. Although the general effects of impurities on the cold ductility of molybdenum have been known in a qualitative manner for some time, no quantitative evaluation of these effects has been available. The present investigation was made in order to determine more accurately the effects of oxygen, nitrogen, and carbon on the cold ductility of cast molybdenum. Oxygen has long been known to be detrimental to ductility, although the minimum amount which will embrittle molybdenum has been open to speculation. Parke and Ham" showed that ingots with oxygen contents above 0.003 pct could not be forged. Maringer and Schwope have described the embrittle-ment of molybdenum wire by oxygen. A discussion on the effects of heat treatment on the distribution of oxygen in molybdenum has been given by Perry, Spacil, and Wulff." Although nitrogen would also be expected to have harmful effects on ductility, no extensive work has been done previously to determine whether this is so. However, Tury and Krausz" found that wires presumably with less than 0.007 pct N were brittle. Carbon is added to commercial cast molybdenum for deoxidation. Parke and Ham" have shown that molybdenum containing as much as 0.06 pct C could be forged if the oxygen was kept below 0.003 pct. Also, Bruckart and others' found that the room temperature ductility of sintered molybdenum improved with carbon contents up to 0.84 pct. However, Rengstorff and Fischer' found that residual carbide particles in cast molybdenum apparently had an unfavorable effect on room temperature ductility.

Jan 1, 1957

By D. M. Kehn

A method has been devloped for chromatographic analysis Of the vapor and liquid phases Of a a system containing methane to components having 20 or more carbon atoms. The method uses a windowed equilibrium cell in which volumetric phase behavior of the system can be observed accurately and from which small samples of gas or liquid can be withdrawn for analysis. Analyses are made using two chromatographs, one for the lighter and one for the heavier components in a sample. Combination of the two analyses yields a detailed analysis of the gas or liquid sample. The complexity of the condensate heavy ends is evident from the chromatograms of these fractions, and the predominance of the paraffin hydrocarborn serves as a useful marker in interpreting the chromatograms. The K-values obtained in this analytical method are presented for a high-pressure condensate system and predict closely the observed volumetric behavior of the system. INTRODUCTION Quantitative analysis of hydrocarbons from natural gas reservoirs is necessary for several reasons—to calculate the amount of sales gas produced, to calculate the amount of natural gasoline produced, to plan a liquid recovery system, or to calculate the potential economic value of a reservoir produced under one or more of several different conditions. Analysis of natural gas fluids produced to the surface consists of identifying and computing the mol fraction of each component of the mixture. Although methane is the predominant component, varying amounts of ethane, propane, butane, pentanes and heavier components are also present. Materials containing up to 30 carbon atoms occur in amounts which decrease with increasing molecular weight. However, the quantities of components in the 20 to 30 carbon atom range are usually so small that their importance is negligible, and they are undetect-able in natural gas by ordinary analytical methods. All the components up to those having 20 carbon atoms may sigsficantly affect phase behavior, however. Commonly, only the methane-through-pentane fraction is analyzed quantitatively for each component, while components heavier than Pentane are lumped and repored as "hexane- plus". Expensive, tedious techniques are required for analysis of this fraction. Consequently the detailed analyses needed for prediction of reservoir behavior are usually undertaken only when major gas fields are being developed. The need for complete analyses of condensate systems is apparent when it is recalled that most gas fields are produced by pressure depletion. As the pressure declines, some of the heavier hydrocarbons are lost as liquids which are in the reservoir. In many instances the amount of liquid in equilibrium with the gas phase at high pressure constitutes only 1 or 2 mol per cent of the total system. Flash calculations generally must predict the actual amount of liquid with an accuracy of a few per cent in order to be useful. This retrograde condensation has been understood for years, but accurate correlation methods to permit quantitative prediction of phase behavior in the retrograde region are not presently available. The increasing importance of natural gas has made accurate prediction of phase behavior and composition of produced natural gas streams an economic necessity. The work reported here was undertaken to provide a rapid, economical method for obtaining the vapor-liquid equilibrium information needed to predict accurately the composition of the fluids produced from a gas reservoir throughout its life. TO develop this method, a pressure cell equipped with windows was designed and built for observing the volumes of liquid and gas present at reservoir pressures and temperatures. Use was made of established chromatographic methods for rapid and detailed analysis of both phases. This paper describes the equipment and techniques developed for obtaining vapor-liquid equilibrium data, presents the results of analyses of a condensate system, and indicates the usefulness of these data in predicting hydrocarbon phase behavior. DESCRIPTION OF EQUIPMENT USED The equipment used in obtaining the required information on phase behavior and the complete analysis of hydrocarbon mixtures through C, will be described first, followed by a discussion of the operation of the equipment. It will be helpful, however, to consider first a brief outline of the technique used. A sample of separator gas and liquid is charged to the windowed cell (see Figs. 1 and 2) where volumetric equilibrium phase behavior at reservoir pressures and temperatures can be determined. Then samples of the coexisting phases are withdrawn. The methane-through-pentane fraction is analyzed with a chromatograph equipped with a hot-wire detector, and the pentane-plus fraction is analyzed with a second chromatograph equipped

Jan 1, 1965

By T. A. Read, M. S. Wechsler, D. S. Lieberman

IN the formation of martensite in steel, it has been observed that the habit plane does not change continuously as the alloy content is varied. Instead, it appears that discrete habits correspond to certain ranges of composition. Greninger and Troiano' found that in low-, medium-, and high-carbon steels, the habits are approximately (1l1), (225), and (259), respectively.* The work of Mehl and Van Winkle2 indicated that the change from the (225) to the (259) habit is fundamentally a consequence of the lower transformation temperature rather than the higher carbon content. Also, Otte and Read3 observed that the habit plane orientation for a chrome-carbon steel scattered within a cone of semivertex angle of 5 deg, which was outside of the experimental error in the determination of the habit plane. These observations suggest the importance of investigating what factors in the crystallography of the formation of martensite account for the several types of habit and the inherent scatter in the precise orientation of the habit plane. A theoretical treatment of the austenite-martensite transformation has been given,4 which considers the total transformation distortion to be composed

Jan 1, 1961

By Wallace W. Wilson

The Cook Ranch Field produces from a very permeable lens of Cook Sand of lower Permian or upper Pennsylvanian age, occurring at an average depth of 1.300 ft. The field was discovered in 1926, and has been operated with low pressure gas injection since July, 1927, one of the first such projects in Texas. Cumulative recovery to Dec. 31. 1950, was 14,701,131 bbl of crude oil, an average of 1,013 bbl per acre-ft of oil rection. and 72.5 per cent of the oil originally in place. Analysis of the reservoir performance indicates that grav-ity drainage has been an important factor in the producing mechanism. The high permeability and uniformity of the reservoir were extremely Favorable tor this type of operation. INTRODUCTION The Cook Ranch Field is the largest of a number of relatively small, shallow producing areas near .Albany, in Shackelford County, Texas. This field is one of the first to be operated by gas injection in Texas, and probably is the most successful low pressure gas injection project ever attempted. The field is owned entirely by Koeser and Pendleton, Inc., and Continental Oil Co., and has been operated by Roeser and Pendleton, Inc., since it was discovered. This study has been made possible through the cooperation of Roeser and Pendleton, Inc.. in making availahle a remarkably complete set of records covering all phases of their operations. The purpose of this paper is to present a summary of the history of the operations through Dec. 31, 1950, and to analyze some of the factors which appear to be responsible for the success of the project. Information concerning the physical plant and the early gas injection history has been presented in an earlier paper.' RESERVOIR CHARACTERISTICS production in the Cook Ranch Field is from a large lens of Cook Sand. of lower Permian or upper Pennsylvanian age, occurring at an average depth of 1.300 ft. The average dip of the sand body, as shown in Fig. 1. is only about 50 ft per mile to the northwest. The reservoir has an area of 930 acres and contains 15,512 acre-ft of Sand, consisting of about 14.512 acre-ft of produc-tive oil zone. and an estimated 1.000 acre-ft of primary gas-cap. The iso-pachous map (Fig. 2) was prepared from drillers' logs. Recent coring in the field has proven these logs to be quite accurate. The productive limits of the field are defined by shale on all sides but the southwest where a small zone of edgewater was encountered. This water does not appear to have encroached into the reservoir, and water production has been small. A smaller producing area to the south of the Cook Ranch Field also produces from the Cook Sand. but is separated from the reservoir under consideration by a band of shale. The sand consists of well sorted, coarse grained. rounded and subangu-lar quartz fragments. very poorly cemented. The analysis of 46 chip-core samples from two recently completed test wells indicates a range of porosity values between 12.5 and 28.2 per cent. wit11 an arithmetic average of 24.0 per cent. Air permeability values range between 50 and 2,300 md, with an arithmetic average of 1.200 md. The reservoir where cored is a Solid sand body. with no discernible major shale breaks or impermeable streaks. Vertical permeability appears to be of the same magnitude as the horizontal permeability. A core of the Cook Sand was cut ill the smaller field to the south, using lubricating oil as drilling fluid. The connate water content of the sand in this core was found to average about ten per cent, and the porosity and permeability were comparable with the values reported above. No analysis was made of subsurface or recombined hydrocarbon samples,

Jan 1, 1952

By E. Posnjak

IT is rather the general belief that acidified solutions of ferrous salts are readily oxidized when in contact with air, and often elaborate pre-cautions are taken to prevent it. This, however, is not the case and several statements may be found in the literature expressing surprise at the extreme slowness with which oxidation takes place when air or oxygen is bubbled through such a solution. Thus C. Baskerville and R. Stevenson1 "observed with surprise" that no. oxidation apparently took place, as shown by titration with 0.5 N KMnO4, when a stream of air was passed for 3 hr. through an acidified solution of ferrous ammonium sulfate or ferrous sulfate. The same authors state that even the presence of salts such as cobalt, chromium, copper, manganese, etc., which usually act as oxygen carriers, had "no effect upon the oxidation as was observed by, passing air for 3 hr. through solutions of Mohr's salt acidified with sulfuric acid." While this statement will be proved further on to be at least partly incorrect the slowness of the oxidation of ferrous salts alone has been previously established by McBain.2. His investigation also showed that the rate of oxidation increases markedly with an increase in the concentration of ferrous sulfate as well as that of oxygen; the concentration of free acid had a comparatively small influence, which in the case of sulfuric acid was to retard slightly the rate of reaction. More recently R. Thomas and E. T. Williams3 investigated the catalytic effect of nitric oxide on the oxidation of ferrous salts, which had been earlier patented by McCulloch.4 They found that the probable mechanism of the catalytic action was the oscillation of the catalyst between two stages of oxidation and its interaction alternately with the oxygen and the ferrous iron.

Jan 1, 1927

By Dudley Homer

MINAS DE MATAHAMBRE, S.A. is a Cuban mining corporation with mines located in the Matahambre district about 100 miles westerly from Havana in the Province of Pinar del Rio. The port of entry is the subport of Santa Lucia on the north coast of Cuba. The mines are located six miles inland at the town of Minas de Matahambre. Minas de Matahambre and Santa Lucia are connected by a 9-mile automobile road, and a 30,000-ft. Leschen aerial tramway. At the subport of Santa Lucia the company maintains docks, concentrate bins, tugs, lighters, and miscellaneous shipping equipment. The power plant of the company is also located at Santa Lucia. Connection between the power plant and the mine is effected by a 30,000-ft. transmission line. In the town of Minas de Matahambre are located the mines, concentrator, shops, and warehouses. The con-centrates are transported to Santa Lucia by the Leschen aerial tramway. The mines are equipped with three shafts, viz., Nos. 1, 2, and 3. (Fig. 1.) No. 1 Shaft is a three-compartment vertical tim-bered shaft and has reached a depth of 1825 ft. This is the present main hoisting shaft. No. 2 Shaft is a four-compartment vertical shaft lined with steel sets and native hardwood lagging. Certain portions where the ground is heavy have been lined with re-inforced concrete. Practically all production will be hoisted eventually through this shaft. No. 3 Shaft is a three-compartment vertical timbered shaft. It has reached a depth of 1090 ft. Its purpose is for prospecting, ventilation, and handling men and sup-plies through the north section of the mine.

Jan 1, 1933

By P. K. Strangway, H. U. Ross

Briquets consisting of pure artificial magnetite, pure artificial hematite, and mixtures of the two were reduced by hydrogen in a loss-in-weight furnace at temperatures in the range 500° to 1000° . The rate of reduction of the pure hematite briquets increased continuously with increased temperature. In contrast, the pure nmgnetite briquets exhibited a pronounced rate ninimutn at about 700°C. Metallographic studies of partially reduced briquets rerlealed that, at this temperature, the he.matite samples reduced in a topo-chemical manner while the magnetite ones reduced uniformly throughout, and after partial reduction their cross sections contained a mixture of iron and unreacted wustite grains. No iron shells could be detected on the surfices of any of these uwstite grains. X-ray diffraction investigations indicated that these grains had a rzinimum lattice parameter when they had been formed at the rate rninimum temperature. Also, it was found that an activation energy of 41,000 cal per mole zoas required for reduction when only these wustite grains were present. Thus, it is suggested that the overall reduction rate of the rnagnetile su?nples at temperatures in the range influenced by the rate nzinirnum phenomenon was limited by the rate qf iron ion diffusion in the unreacted wustite grains. THE rate minimum phenomenon, which has often been observed when reducing iron oxides at a temperature of about 700°C, is one of the most interesting, yet unresolved, problems in the field of reduction kinetics. Basic principles of chemical kinetics and 'In some instance, a second rate minimum has been observed at about 900°C. Since most investigators are in agreement that this minimum is directly related to the transformation from a to y iron (which takes place at 911°C) and since it was not encountered during the present reduction tests, it will not be referred to in this vaver. fundamental laws of diffusion all agree that, as the temperature is increased, the rate of reduction should also increase. However, with certain ores, it has been found that their reduction rate actually decreases with an increase in temperature up to some value X where a minimum reduction rate is reached. With further temperature increases beyond X the rate becomes more rapid again. Temperature X is usually referred to as the "rate minimum temperature", while the overall type of behavior constitutes the "rate minimum phenomenon". This phenomenon has been reported by numerous investigators. They have found rate minima during the reduction of both artifiial' and natural374 magnetites and artificia15j6 and natural5" hematites. Rate minima have been observed when reducing high-purity material2 or low-grade ores,3'4 when studying particles in the micronsize range5 or relatively large agglomerates,g10 and during reduction with either hydrogen7 or carbon monoxide.11"2 Previously, this phenomenon has been attributed to many factors; these include sintering and recrystallization of the iron formed during reduction374 changes in microporosity of the ore upon redction,"" formation of dense iron shells around retained wustite grains,11716 and chem-isorption,17 to name only a few. However, most investigators who have reported a rate minimum merely speculated as to what seemed to influence it and they did not examine the fundamental causes. Consequently, the present experimental study was initiated in order to evaluate the basic factors which could be associated with this phenomenon. MATERIALS AND METHODS The experimental techniques, followed during this investigation, are similar to those which have been described previously.18 The chemically pure magnetic powder was prepared by partially reducing Fisher reagent-grade hematite with a gaseous mixture of carbon monoxide and carbon dioxide in a rotating-drum furnace. Three-quarter-inch diam cylindrical briquets which weighed about 12 g were formed from this magnetite powder and pure hematite powder. All of the briquets were sintered while they were slowly raised through the 1200°C hot zone of a vertical tube furnace. An argon stream was continually flushed through this furnace in order to prevent oxidation of the magnetite briquets, while in the case of the pure hematite briquets sintering was carried out in air. The sintered hematite briquets had a density of 5.06 g per cu cm while the density of the sintered magnetite briquets was 4.27 g per cu cm. The sintered briquets were reduced by purified hydrogen in a loss-in-weight furnace at temperatures in the range 500" to 1000°C. In all instances, the critical reducing gas velocity was exceeded and, in order to ensure that the results were reproducible, duplicate briquets of each type were reduced under each set of experimental conditions. A continuous record of the weight loss during reduction was obtained with the aid of a Statham transducer. The present experimental setup was capable of detecting a change in weight as small as 10 mg. Since a weight loss of over 2 g usually occurred during each reduction test, an accuracy of better than 0.5 pct of the total weight loss could be achieved. RESULTS AND DISCUSSION Reducibility Tests. In the first set of experiments, pure hematite and pure magnetite briquets were used.

Jan 1, 1969

By George A. Colligan, John M. Lo

Electrical resistivity as a function of temperature was investigated in undercooled gallium and under-cooled Ga-In alloy of eutectic compositian to examine structural changes in undercooled melts. A continuous linear extension of the resistivity was determined for 99.999 pct pure gallium when undercooled below the stable Ga(l)-liquid, and the metastable Gafl)-liquid equilibria. In icndercooled Ga-In, a significant continuous negative departure from linear resistivity behavior was observed below the eutectic temperature. All resistivity measurements were made by the four-point probe technique. ThE temperature range for investigations into the physical properties of liquids before freezing has been greatly extended with the undercooling of massive melts of pure metals and alloys. Experimental determinations of thermal and transport properties and diffraction patterns in undercooled systems should throw further light on the structural behavior of liquids. Many measurements showing prefreezing anomalies in viscosity1'5 have been regarded677 as evidence for structural groupings in the liquid state. However, the majority of viscosity results,~)~-~~ conforming to the law 17 =A exp(~/RT), do not support theories of atomic aggregation. For the system Cd-Sb, which exhibits a metastable solid phase, Fisher and Phillipsg reported that, in undercooled alloys, the activation energies for viscous flow below the stable liquidus are much higher than those above it. Similarly, Miller et a1." observed a doubling of the activation energies for electrical conductivity in undercooled Cd-ib alloys. These effects were suggested as indicative of atomic association and clustering in the liquids at lower temperatures. With the recent establishment of metastable phases in pure gallium22 and its alloys,23 attempts were made during this investigation to undercool bulk samples and to determine the temperature dependence of electrical resistivitv. Pure gallium, when undercooled below -17°C at atmospheric pressure, can crystallize to either a stable Ga(1) phase (mp, 29.78"C) or a metastable phase identi-

Jan 1, 1967

By R. A. MacGregor

The Stanrock mine of Stanrock Uranium Mines Ltd. is located on Quirke Lake in the Elliot Lake area of northern Ontario, about 25 miles north of Lake Huron. The property was developed and brought into production at a rate of 3000 tons of ore per day during the uranium boom of the mid-1950's. The mine workings are from 1200 to 2100 ft below sea level. Mining was done by the room-and-pillar method with 65 to 80% extraction. The plant is located at an elevation of 1400 ft above sea level. The orebodies are conglomeratic beds, 6 to 40 ft in thickness and dipping 5º to 40º. The ore is a quartz pebble conglomerate with a pyritized sericitic matrix. The ore minerals are brannerite, frequently intergrown with anatase or rutile, uraninite, and some monazite and minor coffinite and thucolite. Sulfides constitute 5 to 10% of the ore as pyrite with minor amounts of pyrrhotite, chalcopyrite and galena.

Jan 3, 1969

By H. H. Reamer, B. H. Sage

An experimental investigation was conducted upon five different paired samples of oil and gas from a field in Louisiana. The study, with each pair of samples, included the measurement of the formation volume and the volume of the liquid phase for three mixtures of the oil and gas. The gas-oil ratio varied from approximately 200 to over 40,000 cu ft per bbl and measurements were made at temperatures between 40" and 250°F. The gravity of the tank oil for the five samples under investigation varied between 38.0" and 55.8" API. The composition of the oil and gas samples and their mixtures is submitted 'References given at end of paper. Manuscript received at the office of the Petroleum Branch February 21, 1950. in tabular form. A number of diagrams depicting the effect of temperature and gas-oil ratio upon retrograde dew-point pressure are presented. INTRODUCTION During the past two decades a fairly large number of investigations were made of the volumetric behavior of naturally occurring hydrocarbon mixtures. The earlier work of Beecher and Park-hurst' and a more recent report on samples from Dominguez Field2 are typical of research of this nature. Such studies have been used in estimating the volumetric behavior of fluids in producing fields other than those from which samples were taken. Progress has been made3.4.5 in correlating the influence of pressure, temperature, and composition upon the specific and formation volume of hydrocarbon mixtures of relatively low gas-oil ratios, but attempts to extend this correlation to higher ratios have not been particularly successful. The influence of composition upon the volumetric behavior of such systems cannot be simply related to a single parameter such as gas-oil ratio. In order to aid in the extension of the correlation of the volumetric behavior of mixtures of oil and gas to higher ratios, a rather complete study was made of five different pairs of samples from a Louisiana field. The complexity of the influence of composition upon the volumetric and phase behavior of such systems in the regions of retrograde condensation was indicated by earlier Work,6,7,8,9,10 and it is doubtful if simple correlations can be established in these regions with the information currently available. The terminology employed in this paper is identical to that utilized earlier."

Jan 1, 1950

By Carl Davis

A description is given of grinding practice on the Rand and of experiments made to improve that practice. The paper includes a description of the experimental plants and methods and the results obtained. THE first tube-mill on the Rand was put into operation in May, 1904, at the Glen Deep Mine. From that time onwards, tube-mills were added to various plants, although little was known regarding the capacity of a given tube-mill when working on banket ore. Within a few years, however, the so-called standard size (length of shell 22 ft. 0 in. diameter 5 ft. 6 in.) was generally used until the last year or two. Practically the only exceptions were about 30 tube-mills having a length of 16 ft. and a diameter of 6 ft., and a few open-end mills of the roller-supported type. Most of the information obtained during the last 15 years has been obtained with mills of the standard dimensions. The adoption of the tube-mill as an accessory to the stamp mill was rapid; and where 3 tube-mills were working on the Rand at the end of 1904, 244 were in use seven years later.1 By 1910, good practice provided 1 tube-mill for 20 stamps of 2000-lb. falling weight. The horsepower of the motors driving the tube-mills had increased from. 80 to 100 and then to 125 at this date. Broadly speaking, current practice at that date aimed at a final product of which 60 per cent. was suitable for sand treatment and 40 per cent. for slime. The sand grading was +60 mesh, 6 per cent.; +90 mesh, 25 per cent.; -90 mesh, 69 per cent.; and the slime grading -200 mesh, 2 per cent.; -200 mesh, 98 per cent.

Jan 12, 1924

By W. E. Crawford

The Fresnillo Company's mill at Fresnillo, State of Zacatecas, Mexico, treats oxide ores from the Fresnillo mine, dump ores and underground ores from the Plateros district, company leases and custom ores from the Zacatecas district, custom ores from other districts and tailings from old dumps at Fresnillo. The normal capacity of the mill is approximately 2600 dry short tons per 24 hours (a ton of 2000 lb.). The final product of the mill is a precipitate containing gold and silver, which is smelted and shipped as doré bullion to the refinery of the Compania Minera de Penoles, S.A., at Monterrey, State of Nuevo Leon, Mexico. The geology of the district was described in 1923, by T. C. Baker,' from whose paper the following data have been taken: The mineralization of the district was effected in the Tertiary period, following the intrusions and preceding the appearance of the flows. The area within which productive veins have been found is 1 mile long by 1/2 mile wide. The important units of each of the four general fracture systems meet in the central portion of Proano hill, which is an outcrop of graywacke, and where the rock was also intensely fractured by subsidiary movements, resulting in a shattered zone 1200 ft. long by 400 ft. wide. The mineralization was more intense in the immediate vicinity of the principal channels through which the solutions rose. The valuable metals are silver and gold, the ratio by weight of the former to the latter being 1000 to 1.5. Argentite is the predominant silver mineral, and is associated with pyrite and manganese mineral. The sulfides are primary throughout. A slight secondary action is represented by small quantities of native silver and silver halides, principally cerargyrite, which are found in the upper part of the mine. Oxidation has penetrated with great thoroughness to the lowest horizon so far exposed, this being 420 ft. below the present ground-water level. The shattered mass within the central portion of the hill and near the surface was sufficiently mineralized to produce a large stockwork

Jan 1, 1935

By C. M. Weld

The southeastern coast of China, from Ning-Po to Macao, represents an element in the continental mass of Asia which has at practically all times in the remote past exhibited a tendency to rise father than to subside.

Jan 1, 1915

By John Birkinbine

The favor with which the members of the Institute received Mr. Fernow's paper upon the use of charbon roux in the manufacture of iron has encouraged me to present this paper, in the hope of having the discussion upon the manufacture and use of the oldest and undoubtedly the best fuel for producing pig iron continued. Owing to the advances made in employing anthracite coal, bituminous coal, or coke, or mixtures of them, we are apt to forget how much of our present development is due to the pioneers in iron manufacture and the fuel which they employed in the production of pig iron. In Mr. Swank's last compilation of the iron and steel works of the United States, the furnace capacity of the country is given as 5,868,000 tons, of which 1,000,000 tons can be made in the 264 charcoal furnaces. In other words, over one-third of the furnaces now in existence use charcoal for fuel, and produce more than onesixth of the iron made. If to this is added the 130,000 tons of blooms and billets turned out by the 122 forges and bloomaries, the importance of the charcoal industries will be appreciated.

Jan 1, 1879

By R. W. Carpenter, J. C. Ogle

It is possible, by using pack-rolling instead of conventional rolling, to reduce a number of metals to thicknesses of 2µm or less. Such thinfoils are generally made at room temperature without intermediate annealing. In addition, pack-rolled foils fail by developing pinholes at thicknesses near 2µm instead of developing the shear cracks usually observed in cold-rolled ductile metals. This paper presents the results of a general investigation of the deformation substructure and texture developed in copper and iron pack -rolled from 130 to about 2µm thickness. Electron microscopy showed that in both metals a fine (0.2 to 0.5?µ m) deformation subgrain structure formed during pack-rolling; in neither case was this substructure grossly different from substructures formed during conventional rolling. The deformation texture formed in pack-rolled iron was quite similar to usual bcc textures; however, in the case of copper, the cube texture was stable during pack-rolling and the normal copper deformation texture was unstable. It is shown analytically that the constraining pack induced a large hydrostatic pressure in the foils during pack-rolling. The pinhole failure mechanism is attributed to the presence of the large hydrostatic pressure during pack-rolling; this strongly suppressed the growth of shear cracks. The stability of the cube texture in copper is also probably due to the unusuul stress distribution developed during pack-rolling. EXPERIMENTS at several laboratories have shown that very thin foils of the common structural metals and many of the rare earths can be made by "pack-rolling". 1-3 The technique was originally developed to make specimens for nuclear scattering experiments and foils for X-ray filters. It is also useful for making experimental laminar metallic composite bodies and foils thin enough for direct examination by ultra-high voltage electron microscopy without the need for special thinning techniques. Pack-rolling in the present context means a three-layer pack, with the material to be rolled into foil comprising the center layer. The outer two layers, which constrain the foil during reduction, are ordinarily austenitic stainless steel. Typically, a 130 µm (0.005 in.) metal strip can be reduced to a final thickness of 2 µm or less by this process. This is accomplished at room temperature, without intermediate annealing. It has been observed that foils produced by this process do not exhibit at any stage of their reduction the severe work-hardening found in strip rolled by conventional cold-rolling methods. Neither is the failure characteristic the same."&apos; Conventionally cold-rolled ductile metal strip fails by developing shear cracks on planes whose normals nearly bisect the angle between the rolling direction and normal to the rolling plane; these are planes of maximum shear stress. In pack-rolling this mechanism has not been observed; failure occurs by the formation of pinholes on the foil surface (penetrating the foil). If pack-rolling is continued the hole density increases. These differences in behavior imply the existence of appreciably different substructure in pack-rolled foils compared to substructure in conventionally rolled material, or perhaps that the geometry of pack-rolling has an effect on the foil behavior. This paper describes an investigation of deformation substructure and texture in some specimens of pack-rolled copper and iron, and some considerations of the stress distribution in the foils during rolling that result from the geometry of pack-rolling. EXPERIMENTAL DETAILS Three different materials were used for pack-rolling in the present work: soft copper sheet (99.8 pct Cu, 0.03 pct 0, electrolytic tough pitch) and two types of iron, Ferrovac E* and Armco iron. Each was "Crucible Stccl Co. initially in the form of 130 µm annealed strip with grain size ranges of approximately 10 to 40 µm. The initial texture of the copper (determined as noted below) was the normally observed cube type (001)[100]; there was evidence of a small amount of material in the cube-twin orientation reported by Beck and Hu.4 The initial texture of the Ferrovac E was similar to that reported for recrystallized iron by Kurdjumov and sachs,5 who list the principal orientations as {111}<112>, {001}<110> 15degfrom RD and a weak component {112}(110) 15 deg from RD. The starting texture of the Armco iron was not determined. Pack-Rolling Procedure. A four-high mill was used for all specimens. The work roll and backing roll diameters were 1.625 and 5.25 in., respectively. The peripheral roll speed of the work rolls was about 2.5 in. per sec. All foils were initially reduced from 130 to 100 µm by conventional straight rolling and then inserted into a pack, without any intermediate annealing, for further reduction. The pack consisted of an 0.033 in. (838 µm) thick 3 by 6 in. polished sheet of austenitic stainless steel, folded to make a 3 by 3 in. jacket. After folding, the jacket was given a small reduction to close the fold tightly before insertion of the foil. During pack-rolling a constant change in roll spacing was made every third pass. The roll-spacing change corresponded to a 5 pct reduction in thickness for a new pack. This approached a 10 pct reduction when the pack had decreased to about half its original thickness. At this point the deformed pack was discarded and a new one

Jan 1, 1970

By S. Floreen

Seven iron alloys ranging from 5 to 12 pct Ni and 5 to 14 pct Cr were studied. All alloys transformed to bcc massive martensites. Tempering increased the strengths , probably because of relief of residual stresses generated by the martensite transformation. The major strengthening mechanism appeared to be solid-solution hardening by nickel and chromium. Studies of the work-hardening behaviw, of the effects of prior austenite grain size, and of the effects of changing strain rate and test temperature gaue results very similar to iron or low-alloy steels. Increasing nickel contents markedly improved the toughness at subzero temperatures. Studies of the flow properties did not, however, indicate the reason for the beneficial effect of nickel on toughness. The marine atmosphere corrosion resistance of the alloys was improved primarily by chromium additions, but increasing nickel contents were also beneficial at low levels of chromium. J\ number of maraging and PH stainless steels are strengthened by precipitation hardening in a low-carbon Fe-Ni-Cr martensite matrix. To some extent the resultant properties of these steels must depend upon the properties of this matrix. The present study therefore was conducted to evaluate the transformation characteristics and mechanical properties of a series of Fe-Ni-Cr martensitic ternary alloys. A limited evaluation of the corrosion resistance of the alloys in marine atmosphere was also made. ALLOY PREPARATION Seven 100-lb air induction melts were prepared using electrolytic iron, nickel, and chromium metal additions. The initial Fe-Ni charge also contained 0.05 wt pct graphite to produce a carbon boil during melt down. After melting of the base charge, the heats were refined with 0.1 wt pct additions of manganese, silicon, aluminum and titanium and poured into cast-iron molds. The ingots were homogenized at 1250°C and uni-directionally hot-rolled to 2-in. plate. They were then homogenized another hour at 1250°C, and unidirection-ally hot-rolled to %-in. plate at a finishing temperature of approximately 1050°C. The compositions of the heats are given in Table I. Two additional heats were prepared as 40-lb vacuum-induction melts using electrolytic iron, nickel, and chromium metals, and commercially pure molybdenum chips. A carbon boil, and 0.1 wt pct additions of aluminum and titanium were again employed, but manganese and silicon were not added. The heats were converted to %-in. plate using the procedure described above. The compositions of these heats are included in Table I.

Jan 1, 1967

By G. M. Ikeda, J. G. Sibakin

An investigation was carried out to determine the variables affecting the coiling temperature of strip in the 56-in. hot strip mill. After statistical treatment, equations have been derived to determine the temperature drop between mill and coiler for both full spray (top and bottom) and top spray only practices. The individual influences of each variable in the temperature drop were derived for both practices. Limitations of the present practices were shown and adjustments in cooling for increased rolling speeds were suggested. A method of estimating the required number of sprays, their spacing, pressure, etc., to achieve a desired temperature drop is developed. MAXIMUM finishing temperature of a hot strip mill is mainly determined by the rolling speed, gage, and the temperature of the bar entering the mill. This finishing temperature may be limited by the maximum admissible coiling temperature in cases when either the cooling facilities on the runout table are not adequate or, more generally, when the cooling capacity of the runout table and the production capacity of the continuous mill are out of balance. Some time ago, the balance between these two factors was not considered detrimental to production. Recently, a new drafting schedule was introduced which increased the production rate, the entry temperature, and hence the finishing temperature. Thus, the restriction of the maximum specified coiling temperature became an important factor for many of the thicker gages. An investigation of the factors determining the coiling temperature may be, therefore, of considerable importance. A brief description of the available equipment will be a useful illustration of the techniques and methods used for this investigation. The 56 in. continuous hot strip mill is composed of six 4-high stands each containing two 221/2-in. diam work rolls and two 45-in. diam back-up rolls. Either of the last two stands can be used as the finishing stand. Which stand is used is dependent on the total percentage of reduction to be taken over the whole train, i.e., on the entry thickness and the final gage. The characteristics of these last two stands are given in Table I. Table I. Operational Characteristics of Nos. 5 and 6 Stands No. .5 NO. 6 Maximum voltage GOO 600 Power, hp 30(10 W00 I normal, kilonmp 4.35 3.73 Rpm of motor and rolls ISO 15 0 ITS to 300 Spettl ot strip, fpm 333 6 to 376T.2 103) to 2062 The speed of the finishing stand varies with the amount of reduction, strip width, and the exit gage. Finishing speeds in general use for varying gages are shown in Table 11. These speeds may change with an increase or decrease in the entry temperature of the strip. Even though the maximum speed of No. 6 stand is shown as 2062 fpm, this has so far never been attained,

Jan 1, 1957

By Seymour G. Epstein

Using a modified capillary-reservoir technique, electromigration of dilute solutions of silver in liquid bismuth has been measured with relatively good precision. The effects of experiment duration, temperature. current density, and silver concentration have been investigated. Chemical diffusion coefficients of silver in liquid bismuth were also measured at temperatures ranging from 300°to 600°C. The effective valence of silver in bismuth was calculated as a function of temperature from a comparison of electric mobilities and diffusion coefficients. In an alloy containing 1 wt pct Ag, the electric mobility of silver increased from 1.65 x X sq cm per v-sec at 300°C to 2.38 x 10-4at 600°C; the diffusion coefficient in-creased from 3.0 to 17.5 x 10-5 sq cm per sec over the same temperature range. Calculated values of effective valence decreased from 0.28 at 300°C to 0.10 at 600°c. ALTHOUGH there has been considerable progress in the theoretical treatment of electron-transport properties in liquid metals, the mechanisms of mass-transport phenomena in liquid metals are still not clearly understood. This is especially true for the case of electro migration, alternatively termed elec-trotransport or electrodiffusion, which is mass transport induced by an applied electric field. A thorough knowledge of the mechanisms governing electromigration will considerably aid in understanding the electronic state of an impurity atom in a liquid metal. Electromigration has been long observed and studied in liquid metals and alloys. However, no satisfactory theory to explain the observed effects has been developed. The disparity in the present theoretical treatments, summarized by Verhoeven,1 has been attributed to the difficulty in describing the momentum transfer between electrons and ions and to the lack of precise measurements in liquid metals, especially at elevated temperatures. Prior to the last decade most of the electromigration studies were qualitative, in that only the direction of migration of alloy constituents was determined with any degree of reliability. These results have been summarized by schwarz,2 who was able to measure the electric mobility of several elements in mercury. More recently electromigration in liquid metals has been measured by a variety of techniques, with a varying degree of success. Mangelsdorf3,4 made precise measurements on dilute amalgams at room temperature, using a technique relating changes in composition to changes in alloy resistivity, but was unable to make measurements at elevated temperatures. Using a modification of this technique, Verhoeven and Hucke5 measured electromigration and resistivities in liquid Bi-Sn alloys. However, the resistivity technique is not sensitive to small composition changes and is impractical for very dilute alloys. Verhoeven and Hucke6 also measured electromigration of several solutes in liquid bismuth by adapting the capillary-reservoir method for determining diffusion coefficients in liquids. The reported precision of these measurements was poor, however, primarily due to the large uncertainties in the chemical analyses to determine concentration changes. Belashchenko7 has summarized the recent Russian investigations of electromigration, many of which, however, are of questionable accuracy. The present study was initiated to develop an experimental technique which would be both versatile and sufficiently sensitive to yield precise measurements of electromigration of solutes in dilute metal alloys at elevated temperatures. Using this technique, a comprehensive study of silver in liquid bismuth was made to determine the effects of experimental variables on the apparent electric mobilities. Chemical diffusion coefficients of silver in liquid bismuth were also measured over the same temperature range for comparison with the electromigration data. EXPERIMENTAL TECHNIQUE Electromigration Measurements. Electromigration of silver in liquid bismuth was measured by the capillary-reservoir technique, similar to that used by Verhoeven and Hucke,6 but modified to yield more

Jan 1, 1967

By D. R. Uhlmann, T. P. Seward, O. Chalmers

A magnetic field has been used to damp out liquid convection during the solidification of castings. Ingots of Al-2 pct Cu were poured from various sperheats (10" to 65°C) into a room-temperature graphite mold located between the poles of an electromagnet. The effect on ingot structure of varying the strength and time of application of the magnetic field was investigated, and the results are interpreted in light 01- current theories of ingot structure. In the solidification of alloy systems, thermal gradients in the melt and differences in density of the constituents are expected to produce convective motion in the liquid. The thermal convection caused by temperature gradients should be present during the freezing of both alloys and pure materials, while the solute convection caused by density differences should be of concern only for alloys. The possible influence of this natural convection on the structure of castings has been discussed by Ruddle,&apos; Chalmers, and Tiller. More recently, an experimental investigation of such effects was carried out by Cole and Bolling. These workers took stationary molds containing lead- and tin-based alloys and. using a brine solution. quenched them from various superheats above their respective liquidus temperatures. When grids were placed across the mold diameter to suppress convection, the grid region was later observed to contain a larger percentage of columnar grains than other parts of the casting or than similar castings poured without the grids present. From thermocouple measurements, they found the temperature in the grid region to be higher than that in the region outside the grids throughout the freezing process, and concluded that convection should be an important mode of heat transfer in normal castings. In addition to such convection arising from thermal gradients or differences in density of the constituents, a further source of convective motion, which we shall call "momentum convection", may be particularly important in small (laboratory-size) castings. By this term we refer to the convective motion produced in the initial pouring process, a motion which is damped out as the linear momentum and angular momentum of the liquid are dissipated. Besides these sources of convection, which are present to some extent in all castings. external influences may also be effective in producing convective motion. Examples of such "forced" convection which have been discussed in the literature include stirring the melt, shaking the mold, rotating the mold, and so forth The purpose of the present study was to examine the effect of convection on the structure of castings poured into a cold mold. In this work, a magnetic field was employed to damp out the convective motions within the liquid, and hence control the extent of con- The effect of a magnetic field on convective currents in a conducting liquid is to induce eddy currents which oppose and damp out the convective motion. vection. The technique of magnetic damping was previously used by Utech and F1emings" in their study of convective effects on impurity banding and other substructure in alloy crystals grown unidirectionally from the melt. In their investigation, fields as small as 200 gauss were found to be effective in damping the convection currents which influence the banding. I) EXPERIMENTAL TECHNIQUE In the present study, alloys of A1-2 wt pct Cu were poured into a room-temperature graphite mold. The mold, in the shape of a circular cylinder, 2 in. ID, 2-3/4 in. OD, 5 in. inside height, and 5-1/2 in. outside

Jan 1, 1967

By Walter Rosenhain

In selecting solid solutions for the subject of this lecture I have been guided by several considerations. The bodies known under that somewhat paradoxical name play a most important part in all types of alloys; consequently, a deeper knowledge of their constitution must &apos;be of fundamental importance to both metallurgical science and practice. Further, having been asked to deal with some of the more theoretical aspects of metallurgy, I have been tempted to describe certain considerations, which I believe to be novel, in regard to the nature of solid solutions. These considerations constitute a theory that requires much experimental confirmation, but they have passed the stage of speculations, for experimental evidence has become available and one inference after another, that can be derived from the theory, is found to be in accord with well-known facts. In putting before you these ideas and inferences, it must be understood that detailed quantitative proof of every step cannot be furnished. Our conclusions must therefore be stated with the reservation that their acceptance must depend on the manner in which the discovery of fresh facts may either confirm or confound them. If we wish to understand the structure of solid solutions we nust carefully realize the manner in which these bodies are formed in alloys. The formation of solid solutions is by no means confined to alloys, but it is desirable to confin5 attention, at the outset, to intermetallic solid solutions. It is not easy to formulate a precise definition of the term "solid solution." It may be said that a solid solution is a crystalline body formed from a liquid solution or from an intimate mixture of solids, or of liquid and solid, that retains in the solid state an admixture of the two substances (solvent and solute) as intimate as that which exists in a liquid solution. The term is undoubtedly paradoxical, for one usually associates solution with a liquid, but the difficulty cannot be evaded by using such a term as solidified solution, for this might refer to a solution that has set, or congealed, without undergoing crystallization. The German term mischkry stall avoids the difficulty and appears to

Jan 1, 1923