Search Documents

By John V. Beall, William F. Haddon

A long the mighty Andean Cordillera, there is splendor beyond imagination-in the natural beauty of the mountains and in daring engineering and lavish investment in the mines. This is the story of the great copper mines of Chile and Peru. Each mine has a special quality which has tested the physical and spiritual resources of the founder. In the early days of the older mines, the mining engineer of song and story was more the rule than the exception. He was physically tough, ingenious and a leader of men. In the current political and social environment of Chile and Peru, the foreign contract mining engineer is still needed; but he must be a different type of man. To John J. Selters at Cerro's Rio Blanco, the principal ingredient is still "toughness," but it is "toughness of mind" that is needed. "He probably should be a teacher." The copper mines are not new. They were, almost without exception, worked by Indians (La Exotica might prove the rule), and later by the intrepid Spaniards. Modern mining began after the turn of the century. In Chile, the first of the big ones was the Braden Copper Co. founded on the El Teniente deposit. This development was followed by Chile Exploration Co. at Chuquicamata and Andes Copper at Potrerillos. These properties have been developed over the years by vast expenditures of money and a monumental amount of labor. None was free of technical problems-metallurgy at Chuqui, marginal grade of the old mine at Andes, avalanches and the great fire at El Teniente. The evolution which has brought the established mines of Chile, and the new ones coming on stream, to their present state of development is in reality the work of wonders of input-money, engineering and responsible management in an atmosphere of political stability. Without any one of these, the result would have been failure.

Jan 11, 1969

By H. A. Koch, R. L. Slobod

This paper discusses a new oil recovery process called the "miscible slug process." This process involves the injection of propane or LPG into the reservoir prior to gas injection. The operating conditions are maintained so that the slug is miscible with both the reservoir oil and the injected gas phase. Thus, a miscible phase displacement is achieved, and high recoveries are obtained from the area of the reservoir contacted. The most striking discovery of the laboratory study which included displacements from cores up to 123 ft in length was that relatively small slugs of LPG are effective over reservoir distances in the miscible displacement of oil. This makes possible the commercial application of the process. The important factors controlling the size of the slug are: (I) reservoir length, (2) reservoir fluid composition, and (3) reservoir pressure at the displacement front. Of lesser importance are the effects of injection rate and porous medium type. Questions which have not been completely answered deal with the effects of gravity and reservoir inhomogeneities on the process. INTRODUCTION One of the major problems facing the oil industry today is recovery of the large fraction of the discovered oil which will remain unrecovered unless some new processes are found. Water flooding has been one successful method used to increase recovery over natural depletion. But even successful water floods may leave 25 to 40 per cent of the pore space filled with residual oil. Recently a process which involves the use of thermal energy has been reported1,'*' which may prove useful in increasing recovery from shallow reservoirs containing highly viscous crudes. This paper deals with a new oil recovery process involving use of miscible phases to displace the oil from the reservoir. Miscible phase displacement oil has been an intriguing idea because the elimination of capillary effects in the reservoir leads to 100 per cent recovery in the areas contacted by the miscible displacing phase. The big deterrent in the past to the practice of miscible phase displacement has been the high cost involved in using large volumes of solvent in the process. The use of high pressure gas to achieve a miscible phase displacement of reservoir oil has been reported4,5 as one economically feasible method. However, this process calls for the maintenance of pressures above 3,000 psi at the dis-placement front. The process described in this paper is not restricted to high reservoir pressures; the only qualification being that the slug of material which is injected into the reservoir must be miscible with both the displaced oil 2nd the displacing phase. Two such cases are the use of an alcohol slug followed by water to achieve a mis-cable water flood, and the use of a low boiling hydrocarbon slug such as propane followed by gas to achieve a miscible gas drive. This paper will deal specifically with the propane dug process. This process will obtain a miscible phase displacement at pressures as low as about 1,200 psi at a reservoir temperature 01 150°F. The process is very simple. The propane displaces oil completely at one front because it is miscible with the oil, and gas displaces the propane completely at a second or trailing front because it is miscible with the propane. A small band of propane should thus remain wedged between the gas and oil phases. This idea has been called the "miscible slug process."6 Unfortunately, the propane slug will become diluted as it flows through the reservoir. This results from a mixing action since the fluids flow through a complex reservoir porous medium rather than simple capillaries. Fig. 1 diagrams a miscible slug displacement. The effects of some of

Jan 1, 1958

By A. S. Richardson

THE conditions that make necessary the mechanical ventilation of the Butte mines of the Anaconda Copper Mining Co. are due to a number of causes, all of which are incidental to the depth at which mining operations are now carried on. The main object to be accomplished, of course, is the reduction of the temperature and humidity of the air in the working places. Ventilation fans, both surface and underground, have been used for many years, but increasing depth has made the problem much more difficult. Further improvement in both ventilation equipment and methods, therefore, became necessary; and it is the purpose of this paper to describe the work planned and done under the improvement program. The mines of the district have been frequently described in various technical publications, so a description is unnecessary here. From a mine-ventilation viewpoint, compared with coal-mine ventilation systems, the problem is complicated by the fact that the workings to be ventilated are situated on a large number of steeply dipping veins which frequently intersect and are faulted, and also by the fact that the extent, or existence, of orebodies is not definitely known in advance of actual development work. For these reasons ventilation work cannot be planned in advance of actual operations, nor can such regular systems of ventilation as are used in working the more uniform and continuous bodies of coal be developed. When operations are conducted at a normal rate, about 10,000 miners are employed on two shifts, so that about 5000 men will be underground at one time. But as ventilation is necessary to reduce high temperature and humidity due, mainly, to natural causes, the quantity of air per man per minute is not a governing consideration in determining ventilation requirements. Most important among the numerous sources of heat and humidity in the mines are : heat generated during decay of mine timber; heat and humidity given off by mine rock and water; heat generated by oxidation of sulfide minerals; heat given off by electrical equipment; heat generated by mine fires (in certain localities).

Jan 2, 1922

Jan 5, 1976

By H. I. Aaronson, C. Laird

The kinetics of thickening and of lengthening of ?' plates in an Al-3.93 pct Cu alloy in the temperature range 203" to 300" C were determined by means of transmission electron microscopy. The rate of thickening was found to be less than that allowed by volume diffusion control at all temperatures, by amounts which increased with decreasing temperature, in agreement with the predictions of a general theory of precipitate morphology.1 Thickening was treated on the basis of the ledge mechanism. Ledges were deduced to spread across the broad faces of ?' plates at volume dzjrfusion-controlled rates, as anticipated from the disordered structure of their edges. Lengthening of 8' plates, on the other hand, took Place more rapidly than allowed by volume dzjrfusion. This occurred despite clear morPhological evidence of a bmrier to growth at the edges of these plates. It was concluded that the misfit dislocation structure comprising the barrier requires that lengthening take place by a jog mechanism. The tnisfit dislocations, however, also serve as diffusion short circuits, and allow high overall lengthening rates to be achieved. In Part I' it was shown that, within the range of aging temperatures and times studied, the broad faces of 8' plates formed in Al-4 pct Cu are fully coherent with the a, matrix. Virtually .all of the dislocations present in these faces were found to have developed as a result of plastic deformation in the a phase. Such dislocations are thus "intruders", rather than the more usual misfit-compensating variety. The edges of 8' plates were confirmed, by extension of the earlier studies of Mat-suura and Koda,3 to be made up of edge-type misfit dislocations, in sessile orientation with respect to lengthening of the plates. These interfacial structures should cause 8' plates to thicken and to lengthen at rates less than those allowed under the condition of volume diffusion control, such as would be expected if the interphase boundaries had disordered structures.' The narrow width of 8' plates, the reproducible crystallography of their broad faces, and the appearance of these plates in cross section as octagons rather than as circular discs2 provide qualitative support for these deductions. The present study of the rate of thickening and the rate of lengthening of 8' plates was undertaken in order to examine them on a quantitative basis. I) THICKENING KINETICS OF THE BROAD FACES OF?' PLATES A) Literature Review. The measurements now available on the thickening kinetics of single-phase precipitate plates consist of one plot of the thickening of a proeutectoid ferrite plate in an Fe-C alloy,' showing (as predicted) thickening rates less than those allowed by volume diffusion control. B) Experimental Procedure. Details of the preparation of the 4-3.93 pct Cu alloy used in this study have been previously reported.4 As in Part 1,' transmission electron microscopy was the observational tool employed. A general description of the apparatus and procedures of the electron microscopy studies is given in Section I of Part I. In thin foils, 0' plates tend to form at and parallel to the foil surface.' A direct investigation of the thickening process by means of hot-stage transmission electron microscopy was therefore not feasible. It was thus necessary to use the conventional method of aging individual bulk specimens for a wide range of different times at the various temperatures studied. In each specimen, the thicknesses of a number of plates were measured. Since thin foils prepared from "bulk-aged" material contain a large proportion of grains with orientations near (001) , it was relatively easy to find, near the edges of the foils, the characteristic multifold patterns of intersecting extinction contours which indicate regions where the foil is exactly at an (001) orientation. The thicknesses of large numbers of plates were measured along the (200) branches of the "stars" so that the 8' plates were precisely parallel to the optical axis of the microscope. Wherever possible, intersecting extinction contours were adjusted with the parameter s > 0 to improve the visibility of the plates in bright-field illumination. These precautions, in combination with taking the measurements at the thinnest parts of the foils, minimized the errors in the measurement of the thickness of the plates resulting from inexact parallelism to the electron beam. Since the plates were very thin, it was not easy to measure their thickness on the photographs. The techniques of enlargement and of microdensitometry were employed to minimize errors from this part of the measurement. A further source of possible error, that the plates can appear thicker because of contrast associated with mismatch normal to the plane of the plate, was also considered. The images of the plates were usually thinner than those of dislocations, however, and no anomalous changes in apparent plate thickness were observed when regions of foil containing plates were tilted through various diffracting conditions. Any error from this cause must therefore be small. Other sources contributing errors were: a) the microdensitometer traces per se and the subjective estimates of their peak limits, and b) slight fluctuations in magnification associated with small changes in the current of the objective lens of the electron microscope. The overall error probably amounted to no more than 5 to 10 pct. In order to obtain readily interpretable data on thickening kinetics, it is essential that the diffusion fields of adjacent ?' plates not be allowed to overlap. Calculations'-' showed that this condition is definitely not ful-

Jan 1, 1969

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 Marcus A. Grossmann

This paper offers for consideration certain somewhat radical modifications in the iron-carbon diagram, these modifications being the result of the presence of notable amounts of alloying elements. When only small amounts of alloys are present, the standard iron-carbon diagram (Fig. 1) can be used with but insignificant changes; when larger amounts of alloys are present, however, it assumes a distinctly altered appearance. No comment is offered for the present except to call attention to the delta area, A4BM, which represents a region of mixtures of austenite and delta iron, just as area A3SP represents mixtures of austenite and alpha iron. Absence of Carbon We may turn at once to the effect of the presence of alloys. It has been found that in the complete absence of carbon, the gamma change will sometimes disappear entirely when sufficient alloying element is

Jan 1, 1927

A shrinkage stope is an overhand stope in which the broken ore accumulates until the stope is completed to, or near, the level above. As broken ore generally occupies at least 60 per cent. more space than ore in place, about a third of this must be drawn out as the stope advances to leave a working space under the back. The ore remaining supports the miners and gives temporary support to walls, and is all withdrawn when the stope is finished. The shrinkage-stope method is applicable to steep-dipping deposits of strong ore with strong walls. It may be applied to narrow or wide veins, and is simple and cheap. Five examples, which include important and varied types of deposits, are given: namely, Kennecott, Homestake, Jarbidge district, Mogollon district, and Cripple Creek district.

Jan 1, 1925

By Francis S. Peabody

This paper will not be a technical paper, because, although I have been in the business of mining and selling coal for 30 odd years, I am neither a mining engineer nor a practical miner. If I digress from time to time from my thesis, I must be forgiven by the expert engineers and highly technical gentlemen for whose proceedings this article is written. Waste of the wonderful store of power that the Creator placed at our disposal appears to have been the theory and the basis of our methods of extracting this power—waste from the time the coal is mined to the time it is consumed. Let us consider the prime causes of this wastage which has been the heritage of the coal mining industry. In the early days—about 150 years after " Stone Cole" was discovered in Illinois by Joliet and Marquette, and Father Hennepin noted a "cole" mine on his map—the mode of mining prevalent among farmer landowners, on whose property coal was discovered near the surface or outcropping on the hillsides, was to enter the seam by a shallow shaft or drift into the hillside and remove the coal by wedging it down until a large room was left. The roof without support would fall and our primitive coal operator would then sink another shaft or drive another drift. In these early operations only the large lumps were taken and all small pieces and screenings were left to be covered by the fall of the roof—in fact this condition prevailed in Illinois up to about 1885. Gradually the method of mining changed from the open chamber, to a single entry with rooms turned to the right and left. Later, as the demand for coal increased and the necessity for larger mines became evident, the "room and pillar" system grew to be regular practice. The room and pillar system of mining consisted of starting away from the shaft bottom or drift mouth, with a pair of entries usually 12 to 15 ft. wide and about 30 ft. center to center, one entry being used for the air intake and the other for the return air and haulage; from each entry rooms or chambers were turned, narrow at the mouth and widening

Jan 1, 1918

By J. E. Fox Jr., J. L. Lummus, J. P. Gallus

Fresh water or brine drilling fluids may be kept free of suspended drilled solids by the addition of a water soluble acrylamide-carboxylic acid copolymer at the flowline. Addition of from .01 to 0.2 lblbbl of the polymer solution to drilling fluids containing less than 5 per cent clay solids by weight causes the solids to flocculate and settle rapidly to the bottom of the pits. Solutions of the polymer injected at the pump suction reduce the loss of water to permeable formations without impairing the permeability to oil. The use of drill-itlg fluids clarified with the polymer has resulted in increased drilling rates, extended bit life, and lower drilling fluid costs. INTRODUCTION Field experience and the results of a number of investigations have established that the accumulation of solids in drilling fluid reduces drilling rate.'-' Drilling with water makes possible higher drilling rates than can be achieved with mud but in many areas drilling with water may not be feasible because of the possibility of encountering high formation pressures or by-dratable formations. To combat these conditions, the drilling fluid must possess certain physical properties such as viscosity, density, fluid loss, etc., which require the presence of solids. The current trend in drilling fluid treatment is to maintain as low a percentage of solids as is possible without harmfully affecting the mud properties needed for drilling. Mechanical separating devices such as wet cyclones and decanting-type centrifuges are proving to be an economical means of controlling the percentage of solids and thereby maintaining low solids muds. Also: special muds have been developed for the purpose of retarding the hydration of drilled solids so that they may be more easily removed by shale shakers or settling pits. In some areas, such as West Texas, the characteristics of some formations will permit drilling with water. However, because of the dispersion of drilled solids, it is usually not possible to maintain clear water even with the aid of mechanical separators, or by utilizing large settling pits. For this reason the commonly used term "water drilling" is a misnomer since the water usually contains some solids. Because of the improved drilling rates and other benefits which might be effected, a laboratory and field study was made of the use of flocculating agents for maintaining clear water for drilling. PROCEDURE Laboratory—Solids Settling Two techniques were employed to determine the effectiveness of flocculating agents in settling solids from drilling mud. First, the rate of fall of solids was measured in graduated beakers containing mud treated with various flocculating agents. Natural gum, oil-in-water emulsions prepared with ethoxylated nonyl phenols and diesel oil. and a powdered synthetic acrylamide-carboxylic acid copolymer* (hereinafter referred to as "polymer") were tested as flocculating agents in both fresh water and salt saturated muds containing 4 per cent solids. The polymer was not added in the powder form directly to the muds but was first dissolved in water in a concentration of 3.5 lb/bbl. The polymer solution was then added directly to the mud. The concentration of the flocculating agents, including the polymer, was varied. High rates of fall of the solids indicated high flocculating efficiency. A second technique consisted of measuring the time in minutes required to obtain clear water at the pump suction after addition of the various flocculating agents at the flowline. These tests were made using a model mud circulating system having a total volume of approximately 10 gal. The natural fresh water and brine muds used contained 4 per cent solids. A sketch of the circulating system appears in Fig. 1. The circulating rate

By A. W. Peake, F. O. Prior

Considering the great advance in the development and application of electricity, it is not strange that eventually a big field for its use has been found in oil-field operations. So far as is known, the first electric drive in oil-field operations was in the Russian field of Baku in 1900. The first application in this country was made by the South Penn Oil Co. near Folsom, West Va. in 1903. In 1916, electric power was first used in the Burma fields of India for drilling and pumping. Between 1916 and 1922, The Empire Gas & Fuel Co. made the first large electrical installation in the Mid-Continent fields. But although the first application was made 27 years ago, it is only within the last 10 years that oil companies have begun to look upon its use with much favor. Within the last few years, there has been a steady increase in the use of electricity in the oil fields. The first application of electricity for oil-field operations in Wyoming was in the Lander field in 1919; the second was in 1924 in Salt Creek; and the third, and last to date, was made by the Continental Oil Co. in the Big Muddy field during 1926. Lander Field The electrification of oil-field operations in Wyoming was initiated by J. W. Steele, superintendent of the Producers & Refiners Oil Corpn., in the Lander field in 1919. At that time, 32 wells were being pumped from five band-wheel powers, with oil engines as the prime movers. Eight barrels of fuel oil were used for power per day and at the price of 90 c. per bbl. the fuel bill was $36 per day. It was decided to try a 15 to 35-hp. oil-field motor on one of these powers. Electric power was generated with steam at the old Wind River refinery station. This test was so successful that in 1920 all five powers were equipped with 15 to 35-hp. oil-field motors, the power being obtained from the Sinks Canyon hydroelectric station. Four of these powers pumped wells at an average depth of 1450 ft., and the fifth pumped wells at an average of 2100 ft. In 1920, the average production per day from the 32 wells was 325 bbl. The power bill on the

Jan 1, 1928

By George M. Fowler

THE Tri-State district, as outlined in this paper, refers to the entire mineralized area in southwestern Missouri, southeastern Kansas and northeastern Oklahoma (Fig. 1). The part of the district in Missouri and near Galena, Kans., is still sometimes referred to as the Joplin district (Fig. 2). The Picher-Miami area is that part of the Tri-State district located contiguously in Kansas and Oklahoma in the vicinity of Baxter Springs, Picher and Miami. This paper is confined almost wholly to the ore deposits of the Tri-State district and particularly to the Picher-Miami area. Our study of the ore deposits of this district dates from late in 1925 (by Fowler) and early in 1927 (by Lyden) to the present. Our work has been confined almost entirely to the search for ore for numerous companies and individuals. It was not possible for us to undertake numerous highly interesting investigations which presented themselves but which would not immediately help in finding ore. We particularly refer to the general structural geology of the Ozark uplift, the genesis of the ore, and other problems of a similar nature. The local and general structural problems of the district are being solved gradually as the work progresses. The factors that control the loci of the several orebodies are evident. This paper is based almost exclusively upon our own observations. Most of the important mines in the Picher-Miami area were studied in detail. A map (Fig. 5) is included which shows this area and the properties we have examined to date. When it was convenient we visited, studied and compared structural relations in numerous mines in states outside the district. Some of these observations are noted in this paper.

Jan 1, 1932

By W. M. Peirce, R. K. Waring

Zinc of high purity offers definite advantages in certain fields. A process by which zinc of 99.99 + per cent purity is produced by pyro-metallurgical methods is described in this paper. The process consists of a fractional distillation following the primary reduction; this fractional distillation employs the principles of rectification for the separation of lead and other high-boiling impurities and cadmium and other low-boiling impurities. Theoretical Considerations Involved in Production of High-purity Zinc by Distillation Fractional distillation, fractional condensation, and rectification are recognized methods of separating mixtures of liquids. In the field of organic liquids these methods are widely used but not commonly to effect as complete a separation of liquids as is done in the problem under consideration. Zinc boils at 905" C., cadmium at 778" C. and lead at about 1620" C. Zinc may contain from several hundredths of one per cent to over one per cent each of cadmium and lead, and the problem is to reduce these impurities to a few thousandths of one per cent. For lead and zinc, the spread in boiling points is substantial, 715° C., while for zinc and cadmium it is only 127" C. The basic limitation of any separation by distillation may be found from the relation between the equilibrium composition of the vapor and the liquid for all mixtures of the two substances involved. If a mixture of constant boiling point is found, or if a stable compound that vaporizes without dissociation occurs, there is a definite theoretical limit to the degree of separation that is possible when operating at atmospheric pressure with respect to that mixture. Otherwise, any degree of separation is theoretically possible. The equilibrium composition of vapor in contact with liquid mixtures of zinc and cadmiurn at the boiling point has been determined experi-

Jan 1, 1937

By J. T. Eash, N. B. Pilling

As a group, the alloys of iron, nickel and carbon are, in application, one of the most versatile of the ferrous alloy family, and while many investigations have been made of their properties and structure only a few attempts have been made to show the microstructural relation over a wide range of composition. It is neccssary at once to be clear about the kind of structural relation with which we are concerned. The equilibrium diagram provides quantitative data regarding structural make-up and its variation with temperature, but equilibrium structures often are far different from the technologically significant ones. This is particularly true of steels and cast irons, and some of the most important cornponents of their structure may have no place in the diagram of equilibrium. The fugitive phases that result from transFormation are dealt with in a highly detailed and descriptive manner in. the S-curves originated by Bain. The present effort lies in a still different field, which is to portray the relation between sweeping changes in composition and in resultant structure, under controlled but nonequilib-rium conditions of thermal treatment. The Guilletl diagram presented in 1903 was the initial attempt at such a correlation and frequent references to this diagram can be found in the literature even though later work has shown it to require considerable modification. Kase2 published in 1925 a diagram that was based upon observations of furnace-cooled melts: At low carbon contents this diagram agreed fairly well with experience in showing pearlite to exist in alloys containing up to 6 per cent nickel, and completely austenitic steels at 24 to 28 per cent nickel. At high carbon contents, however, irons were indicated as being martensitic at around 2 per cent nickel and austenitic at 12 per cent nickel; these interpretations are open to serious question. Based upon experience with steels and cast iron, Wickenden3 suggested a diagram that agreed fairly well with Kase's in the steel range but which presented a wide departure from it in the higher-carbon, high-nickel regions. In its broad picture, the Wickenden diagram is an approach to "practical" structures. Reference may be made at this point to the efforts of Marsh5 to construct an iron-nickel-carbon equilibrium diagram by the coordination of scattered data, which are described at length in the monograph cited. None of these preceding attempts has appeared to meet the need for an exposition of the structural sequence that is encountered in traversing the nickel-steel nickel-cast-iron range under what might be called ordinary departures from equilibrium. ExperimentaT. Conditions Since the intent has been to establish structures developed under arbitrary conditions, experimental details have perhaps more than usual importance. Three of these conditions should particularly be noticed: (I) the material was cast and not subjected

Jan 1, 1942

By J. T. Eash, N. B. Pilling

As a group, the alloys of iron, nickel and carbon are, in application, one of the most versatile of the ferrous alloy family, and while many investigations have been made of their properties and structure only a few attempts have been made to show the microstructural relation over a wide range of composition. It is neccssary at once to be clear about the kind of structural relation with which we are concerned. The equilibrium diagram provides quantitative data regarding structural make-up and its variation with temperature, but equilibrium structures often are far different from the technologically significant ones. This is particularly true of steels and cast irons, and some of the most important cornponents of their structure may have no place in the diagram of equilibrium. The fugitive phases that result from transFormation are dealt with in a highly detailed and descriptive manner in. the S-curves originated by Bain. The present effort lies in a still different field, which is to portray the relation between sweeping changes in composition and in resultant structure, under controlled but nonequilib-rium conditions of thermal treatment. The Guilletl diagram presented in 1903 was the initial attempt at such a correlation and frequent references to this diagram can be found in the literature even though later work has shown it to require considerable modification. Kase2 published in 1925 a diagram that was based upon observations of furnace-cooled melts: At low carbon contents this diagram agreed fairly well with experience in showing pearlite to exist in alloys containing up to 6 per cent nickel, and completely austenitic steels at 24 to 28 per cent nickel. At high carbon contents, however, irons were indicated as being martensitic at around 2 per cent nickel and austenitic at 12 per cent nickel; these interpretations are open to serious question. Based upon experience with steels and cast iron, Wickenden3 suggested a diagram that agreed fairly well with Kase's in the steel range but which presented a wide departure from it in the higher-carbon, high-nickel regions. In its broad picture, the Wickenden diagram is an approach to "practical" structures. Reference may be made at this point to the efforts of Marsh5 to construct an iron-nickel-carbon equilibrium diagram by the coordination of scattered data, which are described at length in the monograph cited. None of these preceding attempts has appeared to meet the need for an exposition of the structural sequence that is encountered in traversing the nickel-steel nickel-cast-iron range under what might be called ordinary departures from equilibrium. ExperimentaT. Conditions Since the intent has been to establish structures developed under arbitrary conditions, experimental details have perhaps more than usual importance. Three of these conditions should particularly be noticed: (I) the material was cast and not subjected

Jan 1, 1942

By Walter H. Bruckner, George B. Clark

SINCE the end of World War II interest has been increasing in the use of shaped charges in the mining industry and in other industries using explosives for blasting purposes. Shaped charges employ the principle known as the "Munroe effect," which was discovered by Charles E. Munroe more than 50 years ago (in 1888). Details of their design have been explained e1sewhere.l,2,3 Fig I shows the essential features of design of two types of shaped charges (with conical and hemispherical cavities) and a schematic sketch of their action upon detonation. The following discussion deals with the behavior of the metal in the cavity liners when they are subjected to intense pressures exerted when the explosive charge is detonated. Among the conclusions reached in research on shaped explosive charges, the following have been established concerning cavity liners: 1,2 I. The optimum wall thickness of a conical cavity liner is dependent upon the apex angle of the cone as well as on the base diameter of the charge. Acute apex angles require thinner walls for optimum performance and more obtuse angles require thicker walls for the same base diameter. 2. Cones were more effective in forming a penetrating jet when the walls were tapered; i.e., the thickness of the wall of the cone increased from the apex down. 3. The physical and mechanical proper- ties of metals have a marked effect upon their performance as cavity-liner material. Boiling point, ductility, malleability, tensile strength, and hardness are among the properties that influence the effectiveness of a metal used as a cavity liner. Lead, for example, makes a wide, flat crater in steel plates. Aluminum makes a deeper crater than lead, and an aluminum alloy having a high tensile strength makes a deeper hole, but slightly smaller in diameter. Cast iron makes a deep, narrow hole. These findings, together with the following analysis under Metallographic Survey of Slug, offer solutions to many of the problems involved in solving the mechanism of the formation of Munroe jets. It has been fairly well established that cavity liners collapse in a manner similar to that indicated in Fig 2. Conical liners are known to collapse upon themselves while hemispherical liners are believed to turn inside out in the process of jet formation. The first has been definitely proved by recovery of collapsed portions of cones, while liners from partly detonated charges show that hemispheres may turn inside out. Fig 3 shows a sketch of a recovered slug from a 6-in. shaped charge using a 45° cone made of cast iron. (This size of charge drilled holes up to 3 ft in depth in solid granodiorite.)

Jan 1, 1947

By Albert Sauveur

This paper explains the possibility of using advantageously a boiling solution of sodium picrate to reveal dendritic segregation in steel. The mechanism of the action of the reagent is described. The failure of manganese alone to produce persistent dendritic segregation is also considered. IRON, like other metals, solidifies through the formation of dendritic crystals; iron alloys forming solid solutions, like other solid solutions, solidify likewise through the formation of dendritic crystals. The alloying elements or impurities as well as the inclusions segregate generally in the interstices, or "fillings," between the axes and branches of the dendrites; that is, in the portions last to solidify. This results in dendritic segregation or heterogeneity, which is generally persistent and makes possible the revelation of the dendritic crystallization of the metal through the selective action of a suitable etching reagent.1 For this purpose, a cupric solution, such as Le Chatelier's, is generally used, copper being deposited on the pure, or relatively pure, ferrite present in the axes while the fillings remain free, or relatively free., from copper deposition. The dendritic structure, formed on solidification in a steel containing 0.50 per cent. carbon, 0.37 per cent. manganese, 0.12 per cent. silicon, 0.07 per cent. sulfur, and 0.035 per cent. phosphorus is shown, after treatment with Le Chatelier reagent, in Fig. 1 under a magnification of 8 diameters. Commercial steel always contains inclusions of manganese sulfide, which are located in the fillings of the dendrites. Comstock has shown that boiling sodium picrate imparts a dark coloration to these inclusions. We find that this reagent likewise reveals dendritic segregations in commercial steel, as shown in Fig. 2, under a magnification of 8 diameters, which represents the same spot as that shown in Fig. 1. The fillings

Jan 2, 1924

By H. L. Luo, P. Duwez, C. C. Chao

BY rapidly cooling alloys from the liquid state, it is possible to obtain solid solutions beyond the equilibrium concentrations, provided that the components are miscible in the liquid state. Typical such cases include CU-Ag,1 Pt-Ag,2 CU-Rh,3 nickel-base alloys with silicon, germanium, and tin,4 and cobalt-base alloys with silicon, germanium, tin, aluminum, and gallium.5 In the present note it is shown that terminal solid solutions can be appreciably extended in A1-Mg alloys. The alloys whose compositions are given in Table I were prepared by induction melting in tantalum crucibles under an argon atmosphere. Both aluminum and magnesium were 99.99 pct pure. Weight losses after melting were less than 0.2 pct for the aluminum-rich alloys and less than 0.4 pct for the magnesium-rich alloys. From these weight losses it was estimated that the compositions of the ingots after melting were accurate within 0.3 at. pct for aluminum-rich alloys and within 0.5 at. pct for magnesium-rich alloys. As indicated in Table I, the compound AuCd10 in which there is an ionic contribution to the bonding. The authors thank Dr. J. H. Westbrook of the Research Laboratory, General Electric Co., for arranging the supply of materials and for his interest. This investigation was supported by the U.S. Atomic Energy Commission under Contract AT(30-1)-1002, Scope I. some of the alloys were also chemically analyzed and the results confirmed the limits of uncertainty based on weight losses. Rapid quenching from the liquid state was achieved by techniques previously described.8,7 The principle of these techniques consists of propelling a small globule of liquid alloy (about 20 mg) onto a copper substrate. The thin foils easily detached from the copper substrate were analyzed by X-ray diffraction using a Debye-Scherrer camera 114.6 mm in diameter and either nickel-filtered copper Ka or iron-filtered cobalt Ka radiation. Since the back-reflection doublets were resolved, the wavelengths used in the computatioas were CuKal = 1.54050A and CoKa1= 1.78892A. Lattice parameters were obtained by extrapolation of the Nelson-Riley function, and the tables compiled

Jan 1, 1964

By Donald L. Ball

The equilibrium of boron nitride, gaseous nitrogen, and solute boron was investigated in Fe, Fe-C, and Fe-Si rnelts by the Sieverts technique. The free ellergy of dissociation of boron nitride, involving -the implied standard states, was evaluated in the range 1400" to 1600°C as: ?Fo = 38,000 - 23.5T, cal ber mole The solute-solute interaction coefficients eBB, ecB , and eg were determined as 0.058, 0.22, and 0.078, respectively. BORON is an important ingredient in some types of steel and cast iron. It was employed at a particularly high level, 0.01 wt pet, in the as-cast malleable iron "CentraSteel".1 In this material, the boron concentration was critical in order to assure graphite, and avoid primary cementite, in the as-cast structure. One possible function of the boron in this alloy was the nucleation of graphite through the agency of boron nitride, which, conceivably, precipitated from the melt during cooling. A research program was instituted to assess the validity of this proposed mechanism. The first undertaking, reported here, was a determination of the thermodynamic possibility of boron nitride precipitation. Data available in the literature on the activity coefficient of solute boron in iron-base melts are inadequate for the present purpose. They will be reviewed briefly, however, so that comparison can be made, when

Jan 1, 1968

By A. C. JR. Boyle

I. INTRODUCTION THE geological field work of the Bully Hill district, upon which this paper is based, was begun July 1, 1908, and covered a period of three months. The time was found too short for a complete report and the district was again visited in the early part of July, 1912,. from which time detailed study of the locality continued until September of the same year. This paper is the result of observations made in the mines in the immediate vicinity of Winthrop, Shasta county, Cal., during these two periods of study. The preparation of this report has been greatly facilitated by various courtesies rendered the writer by D. M. Riordan, President of the Bully Hill Copper Mining & Smelting Co., and by John B. Keating and Herbert R. Hanley, managing officers actively in charge at the mines. The elaboration and further study of the notes and collections were carried on in the laboratories of the Departments of Geology and Mining at Columbia University, and the writer takes pleasure also at this point in expressing his acknowledgments to Profs. James F. Kemp, A. W. Grabau, Charles P. Berkey, and William Campbell, for advice and assistance. In order that one may appreciate at first reading the significance of some of the details which follow, and for the sake of clearness, a brief outline of the geological relationships is here given, together with certain conclusions which have been reached regarding the genesis. of the ores and the gypsum masses. In the Bully Hill mining district an associated series of Triassic lavas and tuffs, chiefly andesites, is preceded as well as followed by sediments. The entire system is tilted so that the original bedding planes dip in general to the southeast. The surrounding region has been greatly disturbed, and in the immediate vicinity of the mines close folding of the later sediments and extreme shearing of the igneous rocks locally is a striking feature. Into the nearly vertical shear zones have been intruded post-Triassic dikes of various rock types in the following order: alaskite-porphyry and andesite-porphyry. Outside the area under consideration diorite dikes are known, but they will not receive attention further than to note that' they, probably, represent a differentiation product of the same magma from which the other two dikes came. In this connection all the dikes have an important bearing on the origin of the ores and of the gypsum found in the mines.

Jan 1, 1914