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By J. M. McDowell

A study has been made to deter~r~irre how the behavior of a water drivee reservoir changes as a function of the permeability of the formation and as a function of the size of the aquifer. The effect of pressure maintenance programs on the rote of nat11rn1 water influx is also studied, (IS well as the influence on the influx of the position of water injection we1ls with reference to the oil-water contact. The results are determined by the use of an electrical reservoir analyzer and are plotted as families of curves of pressure, natural water influx, and water injection vs time or cumulalive production. Two size aquifers are studided. One is limited with a 36-inile radius, and the, other approximates an infinite reservoir. The field remains the same in all respects for the completed. study except that the permeability is changed to agree with that assumed for the aquifer. 1 N TR ODUCTI ON this study was undertaken in -dcr to determine how the pres- sure decline and water influx of a water drive field would change as a function of the rate of fluid withdrawals, as a function of the permeability of the formation, and as a function of the size of the aquifer. The effect of pressure maintenance programs on the rate of natural water influx was also studied as was the position of water injection wells with reference to the oil-water contact. The information has been determined by the use of an electrical reservoir analyzer1, sometimes referred to as a Carter type analyzer. This instrument is an analog type computer which can be set up to represent a water-drive oil field. It can reproduce the past performance of the field in terms of analogous electrical quantities when the proper circuit analog of resistors and condensers has been determined, also, it can determine the future behavior for any method of production which may be selected, or permit the comparison among several different methods. Although most applications of the reservoir analyzer"" have been to thc study of specific field performance, it is intended to use the analyzer here to help understand how various reservoir characteristics effect the final performance of the field and to sec under what conditions water injection will be of benefit and to what extent. Within the oil industry the performance of water-drive reservoirs was first described analytically by LV. Hurst' and M. Muskat2 for certain types of boundary conditions. The solutions of the equations developed involved products of exponential functions and Bessel functions. Later publications by Hurst4 and van Ever-clingen" and the hooks of Muskat6 gave further information on reservoirs with other boundary conditions. They also presented rather extensive curves and tables to help evaluate the analytical expressions involved. A rccent series of publications by Chatas. bascd on the work of Hurst and van Everdingen, gives quite complete charts and tables of data to evaluate the pressure decline or water influx in infinite or limited radial reservoirs. and in linear reservoirs. The curves in all of these publications are given in dimensionless form

Jan 1, 1956

By L. C. Kern

This paper presents information on the use of a new propping agent (malleable aluminum particles) which has been used successfully for producing high-conductivity fractures. The conductivity of a packed fracture depends on the width of the fracture as well as the permeability of the propping material. It is significant that the flow capacity of a propped crack is often increased many fold by propping the crack with a sparse distribution of particles. However, the flow capacity of a sparsely propped crack can be limited by two phenomena: (I) crushing of the propping particles, and (2) embedment of the propping particles in the formation walls. Malleable aluminum particles exhibit interesting properties which tend to overcome these limitations. As high loads are applied to the particles they will deform slightly, rather than shattering. The deformation results in a greater bearing area against the formation wall. This reduces the stress on the particle and reduces particle penetration into the formation. The behavior of aluminum particles under load and the bearing capacities of serveral formation rocks have been measured in the laboratory. By properly using these data, as explained in this paper, the flow capacities of aluminum-propped cracks can be calculated for a variety of conditions. Aluminum particles have been used successfully in the field to prop fractures. Where high-conductivity fractures were needed, the aluminum-propped fractures have given greater well stimulation than could have been expected for conventional fracturing processes. INTRODUCTION The purpose of a hydraulic fracture treatment is to create a conductive channel from the wellbore out into the oil or gas formation. The word conductive is emphasized because we believe that the fracture conductivity (flow capacity) is one of the most important factors influencing fracturing results. Previous papers have pointed out the additional well stimulation that can sometimes be achieved by increasing fracture conductivity. Several years ago, we investigated in some detail the effect of fracture conductivity on productivity increases to be expeced from vertical fractures. Both electrical analog and theoretical studies of unsteady-state flow behavior were made. A discussion of the electrical analog equipment and some of the results of the study were given in a previous paper' by Dyes, Kemp and Caudle. Further details were given recently by McGuire and Sikora.5 Fig. 1 shows the remarkable influence of relative fracture flow capacity and length on well stimulation. Briefly, the study indicates the following. 1. High-permeability formations require high-conductivity cracks for best results. 2. The longer the crack, the higher the fracture conductivity required for best results. 3. If the conductivity of the crack is very large compared to the formation (i.e., flow is not being limited by crack conductivity), then the longer the fracture, the better will be the results. Judging from recently published articles,1,314 there is current interest in methods for obtaining high fracture conductivities. Hence, we would like to present in this paper a discussion of a new fracture propping process (use of aluminum particle) which we have used successfully to obtain highly conductive fractures. There are several factors which influence the conductivity of a propped crack. Conventional fracturing techniques frequently result in a crack completely packed with fracturing sand. For such conditions, the crack conductivity is the product of the width of the packed fracture and the permeability of the propping material. It is significant that a large increase in conductivity sometimes can be obtained by propping with particles which are distributed sparsely (less than a

By P. Pollard

A method has been developed for evaluating acid treatments in fractured limestone fields by breaking down pressure drawdown into three component parts: (I) pressure differcntial across "skin" near the borehole face, (2) pressure differential due to flow resistance in the coarse communicating fissures and (3) pressure differential between the fine voids and the coarse fissures. It is apparent that in most successful acid treatments the first term, skin resistance, has been reduced or eliminated. Further, it is often possible to estimate the volume of coarse fissures associated with the second term, coarse fissure flow resistance. In cases where this volume is comparable with practical acid volumes it seems likely that this resistance also may be attacked with a suitably retarded acid. INTROD UCTION Acid treatment has been successfully applied as a general practice in the limestone wells in the Mara/ Maracaibo districts of Venezuela for some 10 years. At the same time the need has been felt for a more precise method of: (1) evaluating the effect of an acid job and (2) selecting wells which should benefit from an acid treatment. The following method, based on an analysis of build-up curves for wells producing from fractured limestone, provides a means of forecasting the effect acid will have on a well and in many cases the probable order of production rate increase which may be expected. In certain cases it is also possible to calculate the fissure volume through which the acid has to be displaced for best results. Various approximations are introduced in the method, but within the limitations of these the analysis gives an indication of how a well, whether previously acidized or not, may be expected to respond to acid treatment. Suitable build-up curves cannot be obtained on "tight" wells which do not give sustained production and the method is not applicable to such wells. Figs. 1 through 7 illustrate various types of build-up curves obtained from limestone wells in Western Venezuela. Curves are included showing (1) both skin and coarse fissure resistance, (2) skin resistance only, (3 and 4) reduction of skin resistance by acidization, (5) fissure resistance only, (6) reduction of coarse fissure resistance by acidization, and (7) acidization failure. This theory has been successfully applied for over three years during which 22 acid treatments have been carried out specifically to reduce skin resistance and three treatments to reduce coarse fissure resistance. The method has been found to be a useful aid in the selection of wells for acidization.

By O. H. Eschholz

THE electrostatic process of fume precipitation is an excellent example of the successful application of scientific knowledge to an industrial operation. Originally proposed for the precipitation of sulphuric acid mists, it has been extended until at present there is practically no fume carrying gas to which the method cannot be applied. Among the more common applications are: the recovery of non-ferrous smelter flue-dust, iron blast-furnace dust, cement dust, and potash fume. It should be borne in mind that the process is restricted to the precipitation of suspended particles, either liquid or solid, and does not separate gaseous constituents. However, -by proper temperature control, mixtures of vapors having different temperatures of condensation to either solids or liquids may he selectively precipitated. The process consists essentially of subjecting suspended particles, including those too minute to be effectively acted upon by centrifugal or gravitational forces, to such an electrical force that they are driven from the gas stream, acting as a conveyer, and deposited upon a suitable receiving surface. This directional impulse is obtained front the interaction of charged particles and an electrostatic field of definite intensity gradient existing between two dissimilar electrodes, known as discharge and receiving electrodes. In principle, the equipment is equally simple. As shown diagrammatically in Fig. 1, it consists of: (1) A source of high-potential direct current, requiring: (a.) Source of alternating-current energy. (b) Means of transforming from tow voltage to high voltage. (c) Means of converting alternating to direct current. (2) Precipitation chamber having: (a) Transmission tubes for fume-laden gases. (b) Suitably designed and disposed electrodes. (c) Means for affecting removal of deposited solids.

Jan 8, 1918

By R. N. Upadhyay, M. Maleki, I. Fatt

Conventional laboratory core analysis tests on samples of two limestone reservoir rocks indicate that about 20 per cent of PV is in dead-end pores. These tests (electric logging formation factor, mercury injection capillary pressure and miscible displacement) were carried out on 1/4-in. diameter test plugs. Test results show a clear dilference between these samples and sandstone or homogeneous limestone reservoir rock. Although the amount of dead-end pore space can be only roughly estimated, the presence of such pore space seems clearly indicated. Pressure transient studies also show presence of deadend PV. Although they do not give quantitative results, pressure transient data yield a reasonable estimate of the size of the neck connecting dead-end pores to the main flow channels. INTRODUCTION Equations conventionally used to describe reservoir flow behavior contain the implicit assumption that all connected pore spaces contributed to both porosity and permeability. Several authors3-7 have pointed out the changes in pressure transient behavior and in electric log interpretation that may result if this assumption is incorrect and, instead, dead-end or cul-de-sac pores are present. There is a need for laboratory tests that can detect presence of dead-end pores in core samples. With such information on hand the petroleum engineer can make more rational use of the mathematical tools now available for analysis of reservoir flow behavior. This paper describes laboratory studies designed to detect and, if possible, give a quantitative measure of dead-end PV in laboratory-size core plugs. Three reservoir rocks were used, two of which were limestones suspected of having deadend pore spaces and a well-known sandstone, used as a comparison standard, in which there is believed to be little or no dead-end pore space. All the studies were designed to measure the natural dead-end PV; i.e., the pore space which is dead-ended because of rock structure. During multiphase flow in a rock without dead-end pores, some parts of one of the phases can become surrounded by the other, thereby giving (for certain flow behavior) an effective dead-end pV8,9. Such behavior will not be described here.

Jan 1, 1967

By Walter S. McKee

When mixed with common cast steel in quantities ranging from 11 to 131/2 per cent. and properly treated, manganese increases the ductility of the metal and adds greatly to its toughness and resistance to abrasive action, which properties comprise the distinctive characteristics that make manganese steel so valuable for many purposes at the present time.. * At present the manganese-steel foundries of this country have an annual capacity of about 60,000 tons and most of the growth has occurred within the past 10 years. In the early days of the industry it was impracticable to make manganese castings weighing over a few thousand pounds, but at present crusher heads, rolling-mill pinions, and similar castings weighing up to 30,000 Ib. each are produced, and it does not appear that the limit of weight has been reached by a considerable margin. Manganese steel is similar in analysis to ordinary first-class converter metal except that it is high in carbon and contains from 11 to 13.5 per cent. of manganese. From one standpoint manganese steel is similar to malleable iron in that the casting as it comes out of the sand is hard and brittle and must be made ductile by a heat-treating process. The heat treatment is an essential part of the process of making manganese-steel castings and must be properly carried out to secure satisfactory results. The necessity for heat treatment limits the thickness of sections which may be made of manganese steel. Originally the annealing depth was comparatively small, but researches carried on during the past few years have resulted in an increase in the thickness of section up to 51/2 in., which it is possible to treat successfully. Large castings are cored out to a minimum thickness of 51/2 in., thus not only eliminating some of the internal stresses which are invariably set up in a very thick casting, but also reducing the weight and inertia of the piece, an important consideration if the casting is to be a moving part in a machine. At the same time, the thickness of 51/2 in. is sufficient to permit the use of manganese steel for the heaviest classes of machinery.

Jan 1, 1916

By Thomas Wilson

IN a single-crystal cube of iron the arrangement of the atoms is that characteristic of iron at room temperature: the body-centered cubic lattice. X-ray investigation has shown this structure to be characteristic of iron, as it has shown the atomic arrangement of other metals to be characteristic of those metals also. Rarely do substances have more than one characteristic atomic arrangement. Many physical properties of metals are directly connected with their atomic arrangements, so that changes of arrangements produce changes of properties. Only chemical change influences atomic arrangement. If a difference in the physical properties of a metal is caused by a process which involves no chemical change, the cause of the difference in properties must be sought elsewhere than in the atomic arrangement. Frequently this cause can be traced to alteration of crystal orientation. The orientation of a crystal may be defined as the relationship which the crystallographic axes bear to some quantity of reference. A cube of iron appears cubic whether it is regarded from a face, an edge, or a corner. Yet these three positions represent three different orientations of the cube with respect to the observer. It is evident that the orientation of this cube of iron, unlike the atomic arrangement, is not characteristic of iron but is entirely dependent on the previous history of the cube. Most of the processes of metal working, such as wire-drawing, rolling, and bending, change the orientation of the crystals present in the worked metals. These processes usually tend to produce rotation of the crystals into positions approaching a mean. Specimens of metals show-ing this characteristic are said to possess a preferred, orientation. Tensile strength, ductility, and many other properties are influenced by orientation changes; therefore two specimens of the same metal may show different values of these quantities. In metal specimens possessing a narrowly limited preferred orientation, these quantities will vary in magnitude in different directions throughout the specimens. The investigation of the influence of manufacturing operations upon crystal orientation, and hence upon physical properties of metals, is an important

Jan 1, 1929

By David Sinclair, Philip B. Bucky

The dimensions and shapes of mine structures may at present be determined by (1) field experience, (2) structural calculations, and (3) barodynamic tests. § None of these, however, provide information as to the stresses, their direction and distribution in a mine structure. For the design of pillars, the placing of openings relative to working places such as gangways, haulage levels, etc., this information is desirable. Photoelastic methods provide this and, while relatively new, their application in all engineering fields is assuming increasing importance. This paper, therefore, will present the method with a few applications to mining, and with sufficient reference for further study by the reader. PART I The Photoelastic Method The photoelastic method of stress measurement determines the stress distribution in a two-dimensional model by optical means. It makes use of the fact that when a piece of isotropic transparent material, such as glass, celluloid, or Bakelite, is stressed and viewed in polarized** light a picture is seen which indicates by its color bands of light, or fringes, the magnitude of the stresses, their direction and their distribution. General Explanation The stress at any point 0 in a structure (Fig. I), may be resolved into two components, P and Q, each a pure tension or compression, at right angles to each other, called principal stresses.' To fully identify the stress, the values of P and Q and their directions or angle F must be known.

Jan 1, 1940

By David Sinclair, Philip B. Bucky

The dimensions and shapes of mine structures may at present be determined by (1) field experience, (2) structural calculations, and (3) barodynamic tests. § None of these, however, provide information as to the stresses, their direction and distribution in a mine structure. For the design of pillars, the placing of openings relative to working places such as gangways, haulage levels, etc., this information is desirable. Photoelastic methods provide this and, while relatively new, their application in all engineering fields is assuming increasing importance. This paper, therefore, will present the method with a few applications to mining, and with sufficient reference for further study by the reader. PART I The Photoelastic Method The photoelastic method of stress measurement determines the stress distribution in a two-dimensional model by optical means. It makes use of the fact that when a piece of isotropic transparent material, such as glass, celluloid, or Bakelite, is stressed and viewed in polarized** light a picture is seen which indicates by its color bands of light, or fringes, the magnitude of the stresses, their direction and their distribution. General Explanation The stress at any point 0 in a structure (Fig. I), may be resolved into two components, P and Q, each a pure tension or compression, at right angles to each other, called principal stresses.' To fully identify the stress, the values of P and Q and their directions or angle F must be known.

Jan 1, 1940

By J. W. Dougherty, J. M. Douglas

THE Hollinger gold mine is in the Porcupine mining division, District of Cochrane, in the northern part of the Province of Ontario. The adjacent town of Timmins, with a population of 25,119, lies 490 miles by railway north of the city of Toronto. GEOLOGY The property is situated on the northwest limb of a major syncline, which pitches northeast at approximately 50°. The principal rocks of the Hollinger area are of pre-Cambrian age and consist of altered, schistose, Keewatin lava flows intruded by stocks of schistose, quartzfeldspar porphyry generally assigned to the Algoman period. The structure of the Keewatin series is extremely complex as a result of close folding and some faulting. The schistosity, trending north 70° east and dipping steeply to the southeast, is most highly developed along a subsidiary anticline in which the major porphyry bodies occur. The ore bodies, which exhibit three principal structures, consist of quartz veins and associated pyritized wall rock. Some lodes are composed of en echelon veins, others exhibit a main quartz body with branching stringers and a third consists of a single definite lead. Gold, in a coarse visible form, may be confined to quartz in some ore bodies but in others it is finely divided and is found not only in quartz but also associated with pyrite in the adjacent wall rock. In many veins the distribution of gold is such that there are several ore sections, separated by areas of low-grade material, in the same vein although its physical appearance remains unchanged. The veins form a very complex pattern in an ore zone which in places attains a length of 6000 ft. and a width of 4000 ft. They are most abundant in the Keewatin lavas in the neighborhood of the porphyry bodies. Few of the veins are persistent for long distances, though some

Jan 1, 1940

By Edward Thomas

THE late George S. Rice was active in the investigation of bumps, particularly in the last ten years of his career as chief mining engineer of the U. S. Bureau of Mines. Since most of his investigation was carried out in Great Britain, continental Europe, and-to a lesser extent-Canada, his thinking on prevention was influenced considerably by the experience of those countries. It is not surprising, therefore, that when he was called upon a few years before his retirement to investigate bumps in the U. S. and suggest ways to prevent them, he turned to longwall mining. A longwall method had been most successful in combating the bump hazard in mining coal under deep cover, especially in Great Britain, but the prevailing method there at the time was advancing longwall mining, which he knew was uneconomical under U. S. mining conditions. For this reason he proposed a modified retreating longwall system that he believed included the best features of the advancing method. As brought out by Rice,1 if the cover is 2000 ft and 50 pct of the coal is extracted, the static load on the remaining pillars will be about 4000 psi, which exceeds the ultimate crushing strength2 in most instances. If the pillar coal is overloaded before a pillar line is established, then the abutment zone preceding a line of extraction is no place to split pillars or extract them by any method other than an open-end system. Rice therefore advocated open-end mining, preferably by longwall, but he was willing to compromise with long-face mining if the longwall method was not acceptable.

Jan 8, 1958

By H. F. Korman, M. C. C. Mow, P. K. Dai

INTRODUCTION Detonations of high explosives in soil and rock have been used frequently in civil engineering applications. Of particular interest in recent years has been the development of test methods to simulate the desired blast and shock environments for the testing of protective structures. The United States Air Force, in particular, the Air Force Weapons Laboratory, in conjunction with the Defense Atomic Support Agency, has in recent years, developed special technology for simulation testing of protective structures in soil and rock media. Such a technology, although initially developed for military applications, is rapidly finding its way into civil applications. One of the major problems in the design of the simulation test is the correct prediction of ground motion induced by the detonation of high explosives. This paper presents a useful prediction method which is developed specifically for ground motion in rock that is induced by the detonation of a buried planar array of explosive columns (See Figure 1). The technique of simulating shock environment using such an array is called the Direct Induced High Explosive Simulation Tech- nique (DIHEST). Normally, each shot hole may contain canisters of ammonium nitrate positioned at various depths, or a slurry explosive with detonators positioned along its length (See Figure 1). The depth and width of the array, the spacing of shot holes, the spacing of detonators, the degree of containment, and the charge weight are the variables which govern the induced ground motion

Jan 1, 1971

By N. E. Norman, R. Stier

The mining industry is continually seeking out new and better underground mining techniques. One of the most recent-also, perhaps, the most significant-of the new concepts in underground mining is the use of mechanical rock-boring machines. And one of the problems that concerns us all in this matter is the cost of mechanical rock tunneling. To help answer the oft-quoted question "What will it cost me?" the following pages deal with the operating costs of so-called "medium to medium hard rock" boring machines-i.e., those designed to meet the drilling requirements in 8000 psi to 25,000 psi rock. A few machines are capable of drilling hard rock above 25,000 psi, but the economics of mechanical tunneling in rock that hard is limited at the present time. [ ] For mechanical rock tunneling, there are five main cost factors influencing the expense: Capital Investment, Cutters, Labor, Power Requirements, and Maintenance. These factors give us a good basic picture of the cost of excavation, although muck handling, erecting supports, and other costs directly related to conventional tunneling and mechanical boring enter into the final picture.

Jan 6, 1967

By Clifford Frondel

THE aluminum oxide known as corundum has several varieties that have been used as gem materials since ancient times. These include the red variety called ruby, the blue variety sapphire, and the asteriated types of ruby and sapphire. Asteriated sapphire was known to the ancients under the name of astrios, and descriptions of this gem were given by Pliny and other early writers. The relation of these gem materials to each other as varieties of a single species, corundum, was first clearly established by Haüy in 1805 and J. M. Güthe1 in 1809. Natural gem corundum is obtained principally in Ceylon, Siam, Burma, India, and Australia. Star sapphires and rubies always have been highly prized and in recent years have become particularly popular in the United States. Natural star rubies of large size and fine quality are extremely rare and rank with large and fine emeralds and diamonds as the most valuable of gem stones. Interest thus attaches to the recent success in commercially synthesizing star sapphires and rubies of a size and perfection unmatched by nature.

Jan 1, 1954

By H. E. Lee, P. C. Feddersen, D. R. Gittinger, G. W. Dunn, J. B. Schuettenhelm

The new Bunker Hill slag-treatment plant, designed ior, a capacity of 300 to 400 tons of hot slag per day, was "blown in" April 5, 1943. In the ensuing I5-months period, 157,530 tons of slag was processed, with an average recovery of over go per cent of the zinc and practically all of the lead contained. In addition to this high metal recovery, utilization of the waste heat in the gas and fume venting, the process has enabled the generation of 231,376 tons of steam at 250-lb, gauge. Over the first six months opcration the volume of slag treated averaged somewhat under 300 tons per day. Reclaimed dump slag made up only about 1 5 per cent of the plant feed. In October 1943, preparations for the smelting of additional tonnages of dump slag were completed and the plant capacity was increased to an average of about 420 tons of slag per day. During the nine-months interval since that date, monthly averages of 450 toils per operating day have been maintained several times. The new plant (Fig. I) is constructed in close proximity to blast-furnace operations. The fuming furnace and other necessary equipment are housed in an eastward extension of the existing blast-furnace building. Beyond this housed extension the dust-laden gas is conveyed about the perimeter of a large rectangle formed by the flues, cooling towers and baghouses. The course of a 10-ft. balloon flue, which transports the fuming furnace gas, describes the west and south perimeters. This flue connects with a set of cooling towers located at the southeast comer. The flue and cooling-tower system serving the deleading kiln constitute the north side and the two baghouses, serving the kiln and furnace operations, -border the east side. From these baghouses the several discharge gas flows are come biped and conveyed in to the rectangle, being vented to atmosphere by means of a fan through a centrally located zoo-ft. brick stack. In general, the plant design and operation follow quite closely that dictated by experience gained in years of slag-fuming practice by the Anaconda Copper Mining Go., at East Helena, Mont., and the Consolidated Mining and Smelting Co. of Canada, Ltd., at Trail, B.C., and more recently by the International Smelting and Refining Co. at Toocle, Utah. : Fuming operations at the East Helena and the Tooele plants are more or less identical. Trail practice differs chiefly in the methods employed for the storage of the hot feed slag and in the methods utilized for the handling and cooling of the fuming furnace gas. The new Bunker Hill fuming plant closely follows Trail procedure in the treatment of the furnace discharge gas while East Hclcna methods have been adopted for the storage of feed slag.

Jan 1, 1944

By N. S. Stoloff, M. Gensamer

The effects of temperature, grain size, and magnesium content on the strength and ductility of cadmium were studied in the range -269° to 23 °C. A sharp drop in ductility between -140° and -190°C marked a transition in fracture mode from ductile shear to inter gvanular fracture. The addition of up to 15.35 wt pct Mg in solid solution raised the transition temperature, and for two compositions produced basal cleavages. The relatively high ductility of unalloyed cadmium at cryogenic temperatures is attributed to temperature independence of the yield stress and the absence of dislocation locking. ALTHOUGH numerous studies have been made of the mechanical properties of cadmium single crystals,1-5 no comprehensive investigation of deformation and fracture in polycrystalline cadmium has been carried out. This investigation was initiated to determine the mechanisms of deformation and fracture in polycrystalline cadmium, and to attempt to correlate these mechanisms with the behavior of other metals of hexagonal close-packed structure. A second objective of this work was to determine whether the slip systems and mode of fracture of polycrystalline cadmium could be altered by reduction of the axial ratio, which is 1.886, through alloying. Dorn and co-workers' have been able to induce prismatic slip in magnesium through alloying to reduce the axial ratio. Single crystals of cadmium are so highly ductile that glide strains of 400 pct are observed at room temperature, and 80 pct at -269°c.l Failure in every reported case is by necking down and shearing off of the crystal. Cleavage in cadmium single crystals has never been observed. Magnusson and aldwin reported a ductile to brittle transition for polycrystalline cadmium at about —160 C for specimens tested at a strain rate of 0.05 in. per in. per min in tension. However, even at -196° substantial ductility was retained. The transition temperature was strain rate dependent, impact loading at 19,000 in. per in. per min raising the transition temperature to about -85°C while leaving the low temperature ductility unchanged. No information was given on microstructures or fracture mode, nor were stress-strain characteristics reported. In the present investigation, tensile tests were carried out on polycrystalline cadmium and solid solution Cd-Mg alloys to determine flow stresses, work-hardening behavior, fracture strength, and fracture ductility. Variables employed included temperature, alloy content (and c/a ratio), and grain size.Some compression data also have been obtained for comparison purposes. I) EXPERIMENTAL PROCEDURES A) Polycrystalline Cadmium. Two purities of cadmium were employed in this investigation. Cadmium of 99.95 pct purity was supplied by Belmont Smelting and Refining Co. Cadmium of 99.99+ pct purity was supplied by American Smelting and Refining Co. Threaded cylindrical tensile specimens were machined to give approximately a 1/2 in. long straight gage section with a reduced diameter of about 0.110 in. Specimens were heat treated in evacuated pyrex capsules in the range 140" to 290°C to produce desired grain sizes. All specimens were polished in a solution containing 320 g Cr03 and 20 g NaS04 in 1000 cc of H20. Occasionally this solution caused staining of the specimen, in which case a further polish with a solution of one part HN03 and two parts H202 in two parts ethyl alcohol was employed.' Tensile testing was carried out on a screw-driven Instron machine, at a constant rate of crosshead movement, which for most tests was 0.01 in. per in. per min. Load vs time, and therefore load vs total strain, were recorded. Temperatures from -196" to -40°C were obtained by passing nitrogen gas through a copper coil immersed in liquid nitrogen, and then feeding the gas into a jacket around the specimen. Tests at -269°C were carried out in a helium cryostat, at a crosshead rate of 0.1 in. per in. per min, with specimens of 1 in. gage length. Compression specimens were tested in a jig similar to one designed by ilman. The jig was mounted on the under side of the Instron crosshead. Load was transmitted by means of a rod connected to a movable part of the jig at one end, and the load cell at the other end. A downward movement of the crosshead applied a compressive load to the specimen.

Jan 1, 1963

By H. S. Cannon, F. N. Rhines

IT. H. Hausner( Sylvunia Electric Products Inc., Bay-side, N. Y.)—The results reported by the authors are interesting because they contribute some information on the principles of sintering and also because of a certain practical value for the manufacture of powder . metallurgical parts in production. Pressed powder compacts are frequently sintered in a boat in several layers so that the lower layers are actually sintered under the weight of the upper layers and, therefore, are frequently deformed. The authors gave information on this deformation process by determining the effect of the load on the density. The experimental setup of the authors, however, has a disadvantage—that the sintering occurred in a cylindrical container so that the deformation was stopped in the direction of the diameter. The authors should have rather called this a study of hot-pressing than of sintering. I want to call the attention of the authors and others interested in sintering under load to the experimental work described by Dawihl and Rix.' These authors sintered cylindrical compacts under a lengthwise ten-sional load of 0 to 25 g and found that the shrinkage in length and diameter changes considerably with the load, but that the volume shrinkage is affected very little by the load. H. S. Cannon (authors' reply)—We wish to thank Dr. Hausner for calling attention to the experimental work of Dawihl and Rix. The fact that they found volume shrinkage little affected by varying tensional loads during sintering seems to support the contention that the forces due to loading are equivalent to and additive to the forces which cause densification. This contention is the basis of our comparison of sintering and creep.

Jan 1, 1952

By Gust Bitsianes, Joseph H. M. Beaty

Successful blast-furnace operation depends upon securing an optimum balance between a number of important variables. This balance will vary somewhat from furnace to furnace in the same plant and with raw materials available in different plants. It is difficult to isolate the effect of any one variable unless it has a rather pronounced effect upon the efficiency of operation. The physical properties of iron ore and coke are known to affect the process, yet it is difficult to set up any definite yardstick by which these differences can be appraised. In recent years, whenever practicable, operators have taken steps to obtain better control over the absolute size and uniformity of size of the ore and coke. The size and physical character of the stone, however, have received comparatively little attention, emphasis being placed upon chemical composition, fluxing efficiency, and action as a desulphurizing agent. Since the stone occupies only about 10 per cent of the volume of the stock column, its influence upon permeability is less than that of the ore and the coke. The large pieces now used have a tendency to roll to the center and thus increase the permeability of this part of the stock column. Smaller pieces would be more effective in promoting the permeability of denser portions of the stock. The size and physical properties of blastfurnace stone are important also for reasons best understood by considering the results obtained by the crushing and the sizing of iron ore. Crushing ore to about 2 in. at Provo, Utah, and to about I in. in Alabama produced material somewhat less permeable to gases, even though sized. In spite of some sacrifice in permeability, the efficiency of the process was improved by crushing and sizing the ore, as indicated by a substantial saving in fuel and increased output. This saving in fuel is due in large measure to more thorough reduction of ore in the upper part of the furnace and to a corresponding decrease in the amount of carbon consumed prematurely above the tuyeres by the reaction CO2 + C = 2CO - 70,080 B.t.u. [I] The physical properties of stone, its size and rate of calcination are important because they influence the rate at which CO2 is released and the completeness of calcination before reaching a level in the furnace where the temperature does not exceed 1050°C. (1920°F.). Briefly, carbon dioxide from the limestone or from the reduction of ore may cause premature corn bustion of carbon above the tuyeres. Assuming that 1000 Ib. of limestone is used per ton of pig iron, about 435 Ib. of CO2 will be liberated during calcination of a good grade of stone. If all this CO2 from the stone were to oxidize carbon prematurely, about 120 lb, would be consumed above the tuyeres in a heat-absorbing reaction. The amount of carbon thus consumed when a

Jan 1, 1943

By M. S. Burton, G. V. Smith, A. Rosen

The kinetics of re crystallization and the effect of recovery on recrystallization of pure iron were investigated within the temperature range of 517" to 632 OC. Grain growth and activation energies were also studied. Two stages can be distinguished during recrystallization; the first is gvowth-controlled and the second is nucleation-controlled. The extent to which the first stage succeeds before the second stage begins depends on both temperature of recrystallization and temperature of recovery. The softening of cold-worked metals and alloys due to transformation of the deformed crystals to strain-free equiaxed grains during annealing is well-known, and early inestiators established that recrystallization kinetics is strongly influenced by minute quantities of impurities. Generally, it is believed that impurities decrease the rate of recrystallization and the rate of grain growth. To understand the basic phenomena of recrystallization, investigations should be on pure materials. Most of the research on high-purity materials has been on metals having the fee Bcc materials, and especially high-purity iron, have been studied only in recent years. It is known that recovery may influence recrystalliation;" however, no general description of the influence, applicable to all materials, has been presented. This paper presents results of a study of the recrystallization kinetics of high-purity iron, after 60 pct cold deformation by drawing, with particular reference to the influence of recovery on the rates of recrystallization and grain growth. From observations of these rates, conclusions are drawn concerning nucleation. MATERIAL AND EXPERIMENTAL PROCEDURE Preparation of Material. High-purity iron, prepared by zone refining of vacuum-melted electroiytic iron at Battelle Memorial Institute under sponsorship of the American Iron and Steel Institute, was used in this study. Table I gives the reported chemical analysis of the material, taken at a point near the last molten zone and thereby rep- resenting the maximum impurity level for the entire bar. Prismatic specimens, approximately 10 x 10 X 50 mm, were sawed from the 50-mm-diam bar, perpendicular to the zone-refining direction, and turned to cylindrical shape. These specimens were sealed in quartz capsules under vacuum, approximately 10"e mm Hg, austenitized at 930° C for 15 min, slowly cooled, removed from the capsules, and cold-worked in air by swaging to approximately 20-pct reduction of area. The encapsulating, austenitizing, and swaging operations were repeated two additional times, after which the samples were encapsulated, austenitized, and cold-drawn to 60-pct reduction of area. A further vacuum anneal at 630°C for 120 min and cold drawing to 60-pct reduction of area produced wire 2.8 mm in diameter. The drawn wire was electropolished to remove deformed material on the surface, after which it was sawed into 4-mm-long specimens for the recrystallization study. Microscopical examination before the final cold reduction revealed equiaxed grain structure with very fine grains in a thin layer near the surfaces of the specimen and nearly uniform ASTM 3-4 grain size in the center. Recrystallization Heat Treatment. a) Direct Recrystallization of Cold-Worked The 60 pct cold drawn iron specimens were recrystallized at five temperatures, 517, 556, 590°, 612, and 632C, in a lead bath covered with graphite (the temperature was controlled to 1°C). Specimens were treated for twelve different times at each temperature, and all were water-quenched after heat &eatment. b) Recrystallization Following Preliminary Recovery Heat Treatment. After cold working, specimens were sealed into quartz capsules under vacuum, 105 mm Hg, and recovery-annealed at 362", 400", and 440°C for 20 hr prior to recrystallization. No evidence of recrystallization was found

Jan 1, 1964

By Joseph H. M. Beaty, Gust Bitsianes

Successful blast-furnace operation depends upon securing an optimum balance between a number of important variables. This balance will vary somewhat from furnace to furnace in the same plant and with raw materials available in different plants. It is difficult to isolate the effect of any one variable unless it has a rather pronounced effect upon the efficiency of operation. The physical properties of iron ore and coke are known to affect the process, yet it is difficult to set up any definite yardstick by which these differences can be appraised. In recent years, whenever practicable, operators have taken steps to obtain better control over the absolute size and uniformity of size of the ore and coke. The size and physical character of the stone, however, have received comparatively little attention, emphasis being placed upon chemical composition, fluxing efficiency, and action as a desulphurizing agent. Since the stone occupies only about 10 per cent of the volume of the stock column, its influence upon permeability is less than that of the ore and the coke. The large pieces now used have a tendency to roll to the center and thus increase the permeability of this part of the stock column. Smaller pieces would be more effective in promoting the permeability of denser portions of the stock. The size and physical properties of blastfurnace stone are important also for reasons best understood by considering the results obtained by the crushing and the sizing of iron ore. Crushing ore to about 2 in. at Provo, Utah, and to about I in. in Alabama produced material somewhat less permeable to gases, even though sized. In spite of some sacrifice in permeability, the efficiency of the process was improved by crushing and sizing the ore, as indicated by a substantial saving in fuel and increased output. This saving in fuel is due in large measure to more thorough reduction of ore in the upper part of the furnace and to a corresponding decrease in the amount of carbon consumed prematurely above the tuyeres by the reaction CO2 + C = 2CO - 70,080 B.t.u. [I] The physical properties of stone, its size and rate of calcination are important because they influence the rate at which CO2 is released and the completeness of calcination before reaching a level in the furnace where the temperature does not exceed 1050°C. (1920°F.). Briefly, carbon dioxide from the limestone or from the reduction of ore may cause premature corn bustion of carbon above the tuyeres. Assuming that 1000 Ib. of limestone is used per ton of pig iron, about 435 Ib. of CO2 will be liberated during calcination of a good grade of stone. If all this CO2 from the stone were to oxidize carbon prematurely, about 120 lb, would be consumed above the tuyeres in a heat-absorbing reaction. The amount of carbon thus consumed when a

Jan 1, 1943