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By J. F. Breedis

The morphology and crystallography of marten -site formed during quenclzing were examined by transmission electron microscopy in alloys whose compositions lie between Fe-19 wt pct Cr-11 wt pet Ni and Fe-33 wt pet Ni. Depending upon composition, four types of transformation products were observed in this portion of the Fe-Cr-Ni system. Three of these products are denoted as lath, plate, and surface martensite. The hcp structure found in association with martensite it? certain higlz-clzromium stairzless steels does not influence the transformation crystallogyaphy and cannot he Considered to act as a transitional structure in the transformation from austenite to martensite. DISTINCT changes in the characteristics of mar-tensitic transformations are produced by the partial replacement of nickel by chromium in austenitic iron alloys. Large, discrete martensite plates form in Fe-30 pct Ni, while aggregates of small crystals form in sheets parallel with (111)A austenite planes in stainless steels containing in the vicinity of 18 pct Cr and 8 pct Ni. These transformation structures are termed plate and lath martensite, respectively. In addition, an hcp structure (E) has been observed in certain high-chromium stainless steels in association with martensite. It has been suggested that the E structure acts as an intermediate step in the nucleation of martensitel-' and influences the morphology and crystallography of the final transformation product. However, this structure may be the consequence of the deformation of austenite arising from the shape distortion accompanying the transformation to bcc martensite.' An hcp stacking of atoms is produced in an fcc lattice by the introduction of an intrinsic stacking fault on alternate (111)A planes. At present, the arguments behind each explanation for the E structure are based on circumstantial evidence. This investigation seeks to determine the importance of the hcp structure to the martensitic transformation, and to examine the crystallography and morphology of the structures produced in bulk samples by quenching in alloys whose compositions lie between Fe-19 wt pct Cr-11 wt pct Ni and Fe-33 wt pct Ni. These aspects of the martensitic transformations occurring in these alloys have been studied by electron metallography and selected-area diffraction of foils examined in transmission in the electron microscope. EXPERIMENTAL METHODS The alloys have been prepared from thoroughly mixed powders of pure iron (99.6+ pct, 0.06 max pct C, 0.15 max pct N), chromium (99.9+ pct), and nickel (99.9+ pct). After sintering in an Ar-H2 atmosphere, the mixtures were melted by induction heating in recrystallized alumina boats under purified argon. The ingots were cold-rolled to 0.4-mm sheets (100 pct reduction in thickness) after the removal of at least 1.5 mm from their surfaces by grinding. Three-millimeter discs were punched from the cold-rolled sheet and annealed at 1150°C for approximately 24 hr in evacuated quartz capsules. The average grain size was 40 µ Thin foils for examination in transmission in the electron microscope were prepared from discs quenched to liquid-nitrogen temperature. A depression was first jet-machined into the center of a disc and a thin area (less than approximately 3000A in thickness) was produced at the base of the depression by electropolishing. Electron-microscope studies utilized the RCA EMU-3 and the Philips EM-100B microscopes operating at 100 kv. X-ray examination of the polycrystalline alloys was performed either in a diffractometer or in a

Jan 1, 1964

By S. G. Lasky

EVENTS during and since the war indicate that the nations of the world are trying to initiate an era of international co-operation. Definitions and objectives include social, economic, and human considerations no less than political considerations. The mineral resources of the world and the absolute and relative position of each nation enter into this situation. The possible use of armed might, the application of sanctions, the international flow of commerce, the ways in which this flow may encourage or hamper international well-being, and the influence of international and domestic well-being upon one another are all matters that must take mineral resources into account. If the United States is to act wisely and forthrightly in such matters we must be thoroughly informed as to our position with respect to mineral resources. What is the mineral position of the United States? A variety of widely conflicting opinions are held in authoritative and intelligent quarters: (1) For practical purposes our mineral resources are already exhausted.

Jan 1, 1946

By MARIUS R. CIMPBELL, Edward W. Parker

DESCRIPTION. ACCORDING to the estimates prepared by the U. S. Geological Survey, the area underlain by workable coal-beds in the United States is 496,776 sq. miles. Of this total area, 480 sq. miles contain the entire anthracite coal-fields of Pennsylvania. The bituminous coal-fields are estimated to be contained in areas aggregating 250,051 sq. miles. The grade of coal between bituminous and lignite, and which is designated by the Geological Survey as " sub-bituminous," is estimated to be contained within areas aggregating 97,636 sq. miles, while the areas containing lignite aggregate 148,609 sq. miles. The coal-fields are divided, for the sake of convenience in classification, into six main provinces, as follows: 1. The Eastern. Province, containing the anthracite coal-fields of Pennsylvania and the bituminous coal-fields of the Appalachian region-namely, those of western Pennsylvania, Ohio, Virginia, West Virginia, Kentucky, Tennessee, Georgia, Alabama, and small outlying areas in North Carolina. 2. The Interior .Province, containing the bituminous coal-producing regions of Michigan, Illinois, Indiana, western Kentucky, Iowa, Kansas, Missouri, Oklahoma, Arkansas, and Texas. 3. The Gulf Province, containing the lignite-areas of Alabama, Mississippi, Louisiana, Arkansas, and Texas. 4. The Northern or Great Plains Province, containing the lignite and sub-bituminous areas of North and South Dakota, eastern Montana, and northeastern Wyoming. 5. The Rocky Mountain Province, containing the bituminous and sub-bituminous areas of western Montana and western Wyoming, Colorado, Utah, and New Mexico. 6. The Pacific Coast Province, containing-the areas of Washington, Oregon, and California.

Apr 1, 1909

By R. D. Schoone, J. T. Michalak

Recovery, recrystallization, and texture development of a cold-rolled aluminum-killed steel have been studied during simulated box annealing. Two different initial conditions existed prior to cold rolling: 1) essentially all of the nitrogen in solid solution and 2) most of the nitrogen precipitated as AlN. The combined effect of nitrogen and aluminum in solid solution before annealing was to inhibit recovery and sub-grain growth at temperatures above about 1000°F and to raise the recrystallization temperature range on continuous heating at 40°F per hr from 1000"-1050°F to 1065"-1085°F. For the material with nitrogen and aluminum initially in solution there was an inhibition in the nucleation of the (001) [110] texture component and an enhancement of the (111) [110] texture component. The differences in annealing behavior mzd texture development are attributed to preprecipitation clustering of aluminum and nitrogen at subboundary sites developed by prior cold working. THE annealing of cold-worked aluminum-killed steels has been the subject of numerous investigations.'-'2 These studies have been concerned with kinetics of recrystallization, with microstructure and texture development, and with the individual and combined effects of composition, thermal history prior to cold rolling, and heating rates during subsequent annealing. It has been shown that the inhibition of recrystallization, and the development of the pancake-shaped grain and recrystallization texture characteristic of aluminum-killed steels, can be associated with the precipitation of A1N particles during a recrystallization anneal involving heating rates in the range 20" to 80°F per hr. If the AIN is precipitated before cold rolling or if more rapid heating rates are employed, the cold-rolled steels recrystallize more rapidly to an equiaxed grain structure and texture comparable to that of rimmed low-carbon steel. The retardation of recrystallization, the development of the elongated grain structure, and the pronounced (111) texture have been attributed to: 1) precipitation of A1N at prior cold-worked grain boundaries to form a mechanical barrier to grain boundary migration;' 2) precipitation on the boundaries of the growing recrystal-lizing grains as well as on cold-worked grain boundaries;'" and 3) preprecipitation clustering or precipitation on subboundaries to retard recovery, nucleation, and growth. The present study was undertaken to study in more detail recrystallization and texture development during commercial box annealing of cold-rolled aluminum-killed steels. Comparison of the annealing be- havior after cold rolling, for two different conditions prior to cold rolling, was made in an attempt to define more clearly the role of aluminum and nitrogen in forming the recrystallization texture. A) MATERIAL AND PROCEDURE The material used in this investigation was a commercial low-carbon aluminum-killed steel which was hot-rolled with a finishing temperature of about 1565"F, then coiled at about 1020°F. The composition, in wt pct, was: 0.050 C, 0.30 Mn, 0.007 P, 0.019 Si, 0.03 Cu, 0.02 Ni, 0.02 Cr, 0.045 Al, and 0.004 N. Two 4.5 by 13 by 0.078 in. sections were cut from the center section of a hot-rolled panel and one of these was reheated to provide two different conditions prior to cold rolling: low AlN: as commercially hot-rolled, with aluminum and nitrogen in solid solution; and high AlN: as commercially hot-rolled, then reheated at 1300°F for 3.5 hr to precipitate most of the nitrogen as AlN. ~etallc&a~hic examination indicated that the reheating did not change grain size nor carbide distribution (some spheroidization of pearlite was noted). Texture analysis at half-thickness level showed that both sections had the same substantially random as-hot-rolled texture. The results of check chemical analysis of each sample are given in Table I. Both sections were cold-reduced 65 pct on a laboratory rolling mill to a final thickness of 0.027 in. Cold rolling, in one direction only, was in the direction of the prior hot rolling. Specimens 1.0 by 1.25 in. were cut from the cold-rolled sheets and given a simulated box anneal in an atmosphere of 2 pct HZ-98 pct He. Specimens were heated at a constant rate of 40°F per hr from room temperature to various temperatures in the range 750" to 1300°F and cooled immediately by withdrawal to the water-cooled end of a tube furnace. The temperature in the 6-in. uniform hot zone of the furnace was controlled within 3"F. Selection of the individual specimens was made to give a random distribution of annealing temperatures with respect to location in the cold-rolled sheet. At least two specimens of each condition were annealed to the same temperature and smaller specimens for light microscopy, transmission electron microscopy, and X-ray studies were prepared from each of these. Rolling-plane sections for each of these studies were taken at half thickness. Light microscopy and transmission electron micro-

Jan 1, 1969

By Alfred Weiss

Over the past 25 years hard-rock mining companies have developed a number of profitable computer applications which appear applicable to operations in the coal industry. The evolution of these applications are described and the most profitable discussed. The basic nature of these systems is that they must cut across organizational boundaries. While technological advances contributed significantly to the successful implementation of computers within mining, the human aspects related to organization, management and control of systems projects remain as key to future success in coal as they were and still are in hard-rock mining.

Jan 1, 1983

THE Institute of Metals Division of the A. I. M. E. has joined with the American Society for Steel Treating and the American Welding Society in support of National Metal Week in Philadelphia, Oct. 8 to 12. Individual and joint technical sessions, plant inspection trips, and a general exposition to be held in Commercial Museum have all been arranged. With the coming of the Institute of Metals Division into the circle, the scope of the exposition has been broadened to cover non-ferrous metals, and exhibits of much interest are promised. Headquarters for the Institute of Metals and the American Society for Steel Treating will be at the Benjamin Franklin Hotel, and for the American Welding Society at the Bellevue-Stratford. The American Society for Steel Treating and the Welding Society will hold technical sessions each forenoon at their hotel headquarters. The Institute of Metals Division will hold sessions Tuesday morning and Wednesday and Thursday afternoons; that for Wednesday being a joint session with the American Society for Steel Treating. The latter society will hold independent afternoon sessions on Thursday and Friday. Registration and information desks will be open at the hotels throughout the week, and an attractive program of entertainments has been arranged.

Jan 1, 1928

By Noel Cunningham

MANY excellent descriptions of the mills of the, Porcupine district have been written, but no discussion exclusively devoted to the metallurgical technology has been given. These notes are intended to cover this feature briefly. They are based upon 2 ½ years' mill operation in the district-i.e., practically since the beginning of metallurgical operations. Character of the Porcupine Ore.-There is no oxidized ore in the district, the surface having been deeply planed by glacial action in recent geologic time. The precious-metal content is about in the proportion of 85 of gold to 15? of silver by weight; hence, the silver is practically negligible. There are two classes of Porcupine ore, having very different characteristics; these will be referred to throughout this paper as Class A and Class B. Class A ore is a pure quartz with inclusions of schist. Generally it is heavily fractured .and breaks down readily to sharp, hard grains, about minus 10 plus 20 mesh, requiring further comminution to release the gold. It carries very little pyrite; the gold is entirely free and apt to be coarse, but often spongy, going into solution readily on that account. This gold is 60 per cent. to 85 per cent. free milling, depending on the grade of ore. Class B ore is an iron silicate schist, strongly laminated, carrying 4 to 5 per cent. pyrite; its specific gravity is 2.8 to 3.0, depending upon the amount of mineralization. In breaking the ore in the mine, generally over 25 per cent. of material through a ½ -in. ring is made; the ore readily breaks down in milling and makes a comparatively large amount of non-crystalline slime; owing to its high specific gravity, however, it is quick settling.' In my opinion, the gold in this ore is free, but so finely divided that it will neither pan nor amalgamate; it appears to be disseminated through the rock and not chiefly associated with the pyrite. Veins of Class A ore occur with or without side walls of Class B, and veins of Class B occur unassociated with Class A; more often the veins are closely banded, Class A and Class B alternating, generally with Class B in excess. Both classes of ore are more-or less blocky at times, and with ref¬erence to Class B this is indicative or low gold content.

Jan 3, 1915

By W. Spencer Reid

ALTHOUGH there have been some developments during the last five years which have had far- reaching and important bearing on lead smelting, it cannot be said that any basic principles of pyrometal-lurgy have been discovered. Eighteen or twenty years ago the Dwight & Lloyd sintering machine was intro-duced and literally turned the roasting end of lead smelting upside down. There has been nothing com-parable to the advent of the sintering machine during recent years. Actual blast-furnace practice today is slightly, if any, better than it was five years ago ; although immeas-urably better than it was twenty to thirty years ago. Some tell us that as far as cleanness of slags is con-cerned, it is no better today than in the days of the old Romans. The metallurgist of a generation ago did very good work, considering the equipment he had available. It is true he was working with the cream of the ores, the clean oxides and carbonates and the low-zinc sul-fides. He was troubled very little with high zinc and selected his type of slag according to preference of -some authority such as Eilers, Iles, Raht, Hahn, etc. As these free-smelting ores were depleted the complex ores were encountered, and the metallurgist gradually discovered that he had to forget the old type slags and run a slag according to the percentage of zinc on the charge. I believe it is now universally agreed that SiO2 and CaO must be lowered and FeO raised in a slag as the ZnO increases. The ratio of these variations is practically uniform and can be relied upon over wide fluctuations of the determining element, zinc. These "bastard" slags, as they are sometimes inappropriately designated, are actually in daily use, and the metallurgist of today has been forced to adopt certain standards, as a guide to successful operation. These slags practically refute the old Eilers' theory that all good slags are chemical combinations of SiO2 with FeO and MnO, and CaO and MgO. Eilers' and the other type-slag theories were based upon the assumption that a good slag must con-form to a definite formula, such as 3 (FeO)2 SiO2 + 2 (CaO)2 SiO2 or 2 (FeO)2 SiO2 + 2 (CaO)2 SiO2 which respectively figure 31.3 and 36 per cent SiO2. The SiO2 was supposed to remain constant even with the entrance of impurities such as Zn and A1,0? into the slag. The increasing amount of impurities, espe-cially Zn, soon discredited the theory, for in actual practice the slag failed to run freely.

Jan 1, 1927

By N. Van Wingen

EFFective sand permeabilities can be ascertained from core analysis if the laboratory data are compensated to allow for the presence of connate or residual water. Such adjustments can be made by applying empirically derived correction factors. Effective sand permeabilities can be estimated also from analytical studies of field depth-pressure measurements. In one method the time rate of pressure build-up after a well is shut in from steady-state flow is required, and in the other the direct measurement of a steady-state rate of flow and the corresponding equilibrium pressure. The results of the investigation discussed in this paper demonstrate that these methods for determining mean effective sand permeabilities can be correlated. Introduction In recent years many investigators have demonstrated the practical value of an accurate knowledge of the physical and dynamical characteristics of reservoir sands containing oil and gas. Of these factors, which serve to completely define a porous medium as a container or carrier of fluids, the dynamical characteristics are of particular interest to the production engineer because they afford a direct measure of the rate at which the oil or gas content of a reservoir will become available. The constant that defines dynamically the porous medium as the carrier of a homogeneous fluid in viscous motion is the "permeability." Coke-analysis Method The generally accepted practice in com-piling permeability data has been to analyze in the laboratory core samples taken in the course of drilling through the productive horizon, and to obtain the mean measure of the productive ability or permeability for the interval open to production by graphical integration of the permeability profile. An average permeability ascertained in this manner, however, is useful to the production engineer only for comparisons of wells drilled in the same horizon, as permeabilities determined in the laboratory are measures of only the ability of a porous medium to transmit a single fluid. As a result of many investigations, it has been shown, however, that under actual reservoir conditions water is coexistent with the petroleum and that its presence greatly reduces the permeability of the sand to oil. Empirical relationships showing the effect of the presence of any immiscible fluid A (such as water) in a porous medium on the permeability of the medium to a fluid B (such as oil) have been established separately by Hassler,1 Dunlap,2 and the writer (Fig. I),3 so that the average specific or dry-core permeability as determined in the laboratory can be corrected to give the true measure of the ability of the horizon penetrated to transmit oil, provided the percentage of pore space occupied by connate water is known accurately.

Jan 1, 1942

By N. Van Wingen

EFFective sand permeabilities can be ascertained from core analysis if the laboratory data are compensated to allow for the presence of connate or residual water. Such adjustments can be made by applying empirically derived correction factors. Effective sand permeabilities can be estimated also from analytical studies of field depth-pressure measurements. In one method the time rate of pressure build-up after a well is shut in from steady-state flow is required, and in the other the direct measurement of a steady-state rate of flow and the corresponding equilibrium pressure. The results of the investigation discussed in this paper demonstrate that these methods for determining mean effective sand permeabilities can be correlated. Introduction In recent years many investigators have demonstrated the practical value of an accurate knowledge of the physical and dynamical characteristics of reservoir sands containing oil and gas. Of these factors, which serve to completely define a porous medium as a container or carrier of fluids, the dynamical characteristics are of particular interest to the production engineer because they afford a direct measure of the rate at which the oil or gas content of a reservoir will become available. The constant that defines dynamically the porous medium as the carrier of a homogeneous fluid in viscous motion is the "permeability." Coke-analysis Method The generally accepted practice in com-piling permeability data has been to analyze in the laboratory core samples taken in the course of drilling through the productive horizon, and to obtain the mean measure of the productive ability or permeability for the interval open to production by graphical integration of the permeability profile. An average permeability ascertained in this manner, however, is useful to the production engineer only for comparisons of wells drilled in the same horizon, as permeabilities determined in the laboratory are measures of only the ability of a porous medium to transmit a single fluid. As a result of many investigations, it has been shown, however, that under actual reservoir conditions water is coexistent with the petroleum and that its presence greatly reduces the permeability of the sand to oil. Empirical relationships showing the effect of the presence of any immiscible fluid A (such as water) in a porous medium on the permeability of the medium to a fluid B (such as oil) have been established separately by Hassler,1 Dunlap,2 and the writer (Fig. I),3 so that the average specific or dry-core permeability as determined in the laboratory can be corrected to give the true measure of the ability of the horizon penetrated to transmit oil, provided the percentage of pore space occupied by connate water is known accurately.

Jan 1, 1942

By Jack R. Elenbaas, Donald L. Katz

A radial turbulent flow formula has been developed which permits the computation of the pressure drop for radial flow in gas wells whether the flow is laminar, turbulent, or partially laminar and partially turbulent. Using the formula a complete back-pressure curve has been calculated and analyzed by a comparison with existing back-pressure curves. A procedure is presented for computing the permeability of the porous media when the porosity, sphericity and average particle diameter are known. Introduction Recent studies on the flow of fluids through porous media have provided new methods for computing flow under turbulent conditions. The present study was initiated as an investigation of pressure -drop computations for flow through porous sands in gas wells and as an analysis of present-day back-pressure tests. Although laminar flow exists in the producing formation of gas wells under normal flow rates, turbulent flow does take place adjacent to the well bore. As the flow rate is increased, turbulent flow exists further and further into the producing formation and under open-flow conditions in relatively deep wells a considerable portion of the flow through the sand will be turbulent. In order to calculate a complete backpressure curve for relatively deep wells without resorting to extrapolation of curves drawn from data obtained in back-pressure tests or calculations made in the completely laminar region, it was necessary to have some means of calculating pressure drop for flow through porous sands under turbulent conditions.4.6 As a result, a radial turbulent flow formula was derived from the equations recently presented by Brownell and Katz.1 A rigorous solution of this equation involves a trial and error graphical integration. By making the assumptions of average viscosity, temperature and compressibility factor of the flowing gas, it was possible to graphically integrate the relation for the general case of radial flow of gases through the porous sand of gas wells. A chart has been prepared relating the value of the integral to the radius of the well bore and to the Reynolds number of the flowing gas. The chart actually performs the graphical integration and the solution of the formula is then reduced to a simple trial and error calculation. A typical back-pressure curve is calculated to show the transition from laminar to turbulent flow. This paper will briefly describe the pro-cedurcs for computing flow through porous media, including a method for predicting sand permeability from porosity and grain size and shape. Flow through Porous Media Brownell and Katzl recently reported a correlation for computing flow of fluids through porous media by the use of an enlarged Reynolds number and friction factor in which the porosity of the bed is included as an additional prime variable. The enlargcd Reynolds number com-

Jan 1, 1948

By Donald L. Katz, Jack R. Elenbaas

A radial turbulent flow formula has been developed which permits the computation of the pressure drop for radial flow in gas wells whether the flow is laminar, turbulent, or partially laminar and partially turbulent. Using the formula a complete back-pressure curve has been calculated and analyzed by a comparison with existing back-pressure curves. A procedure is presented for computing the permeability of the porous media when the porosity, sphericity and average particle diameter are known. Introduction Recent studies on the flow of fluids through porous media have provided new methods for computing flow under turbulent conditions. The present study was initiated as an investigation of pressure -drop computations for flow through porous sands in gas wells and as an analysis of present-day back-pressure tests. Although laminar flow exists in the producing formation of gas wells under normal flow rates, turbulent flow does take place adjacent to the well bore. As the flow rate is increased, turbulent flow exists further and further into the producing formation and under open-flow conditions in relatively deep wells a considerable portion of the flow through the sand will be turbulent. In order to calculate a complete backpressure curve for relatively deep wells without resorting to extrapolation of curves drawn from data obtained in back-pressure tests or calculations made in the completely laminar region, it was necessary to have some means of calculating pressure drop for flow through porous sands under turbulent conditions.4.6 As a result, a radial turbulent flow formula was derived from the equations recently presented by Brownell and Katz.1 A rigorous solution of this equation involves a trial and error graphical integration. By making the assumptions of average viscosity, temperature and compressibility factor of the flowing gas, it was possible to graphically integrate the relation for the general case of radial flow of gases through the porous sand of gas wells. A chart has been prepared relating the value of the integral to the radius of the well bore and to the Reynolds number of the flowing gas. The chart actually performs the graphical integration and the solution of the formula is then reduced to a simple trial and error calculation. A typical back-pressure curve is calculated to show the transition from laminar to turbulent flow. This paper will briefly describe the pro-cedurcs for computing flow through porous media, including a method for predicting sand permeability from porosity and grain size and shape. Flow through Porous Media Brownell and Katzl recently reported a correlation for computing flow of fluids through porous media by the use of an enlarged Reynolds number and friction factor in which the porosity of the bed is included as an additional prime variable. The enlargcd Reynolds number com-

Jan 1, 1948

By Frank S. McKenna, Myron A. Pugacz, Clarence E. Jackson

THE notched-bar impact test has proved worth while in certain applications as a test for control of the quality or the heat- . treatment of steel. In view of the serious thought that even so simple a test as the tensile test, has evoked during the past years, it is not surprising that the notched- bar impact test should have inspired much experimental work. The correlation of the great number of data has not been successful, although steady progress has been made toward a better understanding of this test. Progress has been made, especially, in the isolation of the effects of the many variables that control the results. The stress system imposed on a specimen with a notch is so complicated and un- predictable that no simple evaluation of the test has been possible. Because of this uncertainty, many engineers hesitate to use the notched-bar impact test, and this attitude may well continue until a better understanding of the effects of the variables in the test are available. Without doubt, any additional data that may be presented should be accompanied by as complete a description of the details of test as possible, so that it may be added to the general fund of information that is to serve as the basis for the theory of the notched-bar impact test. The many factors that may control the test results have been pointed out repeatedly. The importance of the effect of the type and dimensions of the specimen has been recognized. Most of the work reported by American investigators has been limited to small- size (Charpy) specimens tested as a simple beam; two types of notches (Fig. I) have been commonly used. Considerable data have also been presented by many investigators using a small specimen tested as a cantilever beam; this commonly being called the Izod test. Here, however, a shear component of stress makes the stress system even mare complex than that present in the simple beam type of test, hence a critical analysis is difficult. Much work has also been reported by investigators using the tension type of specimen. A second variable that must be con- trolled is the testing temperature. An indication that the tests were performed at room temperature is not sufficient, since in many steels a variation of a few degrees in the actual testing temperature may be sufficient to give an entirely different range of results. Other factors. such as the com- position and condition of the material being tested and the speed of test, should also be considered. Many investigators have contributed data and theoretical discussions on the problems encountered in notched-bar test-

Jan 1, 1944

By Raymond Ward

IN the past few years several papers have appeared dealing with different aspects of the oxidation of dilute alloys, especially with respect to the formation of internal oxides or subscales. Subscale has been defined1 as that layer or zone of oxide particles precipitated in a matrix of metallic metal in which the oxide particles are dispersed uniformly and occur by diffusion of the oxygen inward from the metal surface. Alloys composed of a solvent metal more noble than the alloying elements are subject to subscaling or internal oxidation. In these alloys the solute must be present in such quantities that if the alloy is exposed to an oxidizing atmosphere at elevated temperatures, the rate of diffusion of the oxygen into the metal will be greater than the rate of diffusion of the solute outward. There is a composition range of the iron-silicon system that falls into this classification. Knowledge of the nature and rates of oxidation of iron-silicon alloys is of great commercial importance, but very little information of this nature is available. Darken2 recently has made calculations to show the limits of concentration of silicon for which subscales are produced in iron-silicon alloys; however, the main thesis of his paper was to analyze and to explain the already existing data. The purpose of this paper is to present the effect of com position, temperature, time, and atmosphere on the type of scale-metal layer obtained and to give some qualitative indication of the effect of these variables on the rates of oxidation. Since this paper is a study of silicon steels that are available commercially, extremely low-silicon and high-silicon alloys are not included. EXPERIMENTAL PROCEDURE The alloys used in the experiment were taken from heats of silicon steel that ranged in analysis from 0.70 to 5.8 per cent silicon. This composition range takes in most of the commercial silicon steels. In Table I are listed the compositions of alloys used. Other than iron and silicon, the alloys normally contained approximately the following impurities: carbon, 0.03 per cent; manganese, 0.07; phosphorus, 0.008; sulphur, 0.02; copper, 0.07; tin, 0.01, and from nil to a trace of chromium, nickel and copper. All of the alloys used were melted in open-hearth furnaces, except where otherwise noted, and were hot-rolled to 0.100-in. plate. Samples approximately 1/2 in. square were then cut from these materials. So that the surface conditions of the samples used for oxidation would be standardized, each sample was ground through 000 emery paper immediately before oxidation. Two different techniques were employed in carrying out the oxidizing treatments. One consisted simply of heating the samples with free access to air. In this treatment the samples were set on edge on a refrac-

Jan 1, 1945

By George B. Lee

DURING The Two Years In Which The New Reduction-Works Of The Copper Queen Consolidated Mining Co. Have Been In Operation At Douglas, Ariz., There Has Developed A Remarkable Condition In Regard To The Corrosive Action Of The Water Used To Cool The Jackets Of The Blast-Furnaces. Were It Not For The Many Contradictory Features, It Might Pass As One Of The Unavoidable Troubles Due To The Composition Of The Water. This Water, Obtained From Wells 600 Ft. Deep, Is Also Used In The Steam-Boilers, And Its Composition, As Shown By The Following Analysis, Does Not Indicate The Presence Of Any Ingredient Which Would Explain The Corrosion Grains Per U. S. Gal. Silica, 0.861 Iron Oxide And Alumina, 0.223 Calcium Carbonate, 0.2111 Calcium Sulphate, Magnesium Carbonate, Sodium And Potassium Sulphates, . 14.850 Sodium And Potassium Chlorides, 9.732 Sodium And Potassium Carbonate, 6.452 32.409 The Jackets Are Made Of Inner Plates 0.5 In. Thick And An Outer Plate I In. Thick, With 3-In. Stiffeners Between The Inner And Outer Plates. In From 10 To 12 Months The Inner Plates Have Been Reduced By Corrosion To A Thickness Of From 1/8 To 1/16 In., While The Outer Plate In The Same Time Is Reduced By Less Than 1/16 In., And The Stiffeners Show Very Little Corrosion. The Plates Are Pitted And Eaten Away In Some Places More Than In Others. There Is Practically No Scale Found On The Jackets, But When Cleaned Considerable Iron Oxide Is Found In The Bottoms. With An Action So Marked, Serious Trouble Would Be Expected In The Boilers, But, On The Contrary, A Recent Inspection By a

Mar 1, 1908

IN accordance with a programme arranged by a committee of the Institute, consisting of Mr. William P. Shinn, of St. Louis, chairman, and Mr. Joseph D. Weeks, of Pittsburgh, secretary, the member's of the Institute, with their ladies and invited guests, assembled in Chicago on Sunday morning, August 22d. A special train, provided by the Chicago and Northwestern Railway,. left Chicago on Monday morning at 7.50 o'clock, and conveyed the party to Marquette, arriving at 9 o'clock P.M. Here the steamer Northern Queen, which had been chartered by the committee for the accommodation of the Institute, was in waiting, and the members and ladies at once took up their quarters on the boat. EXCURSIONS IN THE MARQUETTE IRON REGION. Local Committee. EXECUTIVE. -J. C. Morse, chairman; C. Y. Osburn, secretary ; D. F. Wadsworth, treasurer; C. H. Hall, H. Merry. RECEPTION.-S. P. Ely, J. P. Pendill, E. Breitung, W. F. Swift, A. P. Swineford, J. C. Fowle, C. G. Griffey. TRANSPORTATION.-Samuel Schoch, D. Morgan, D. H.. Merritt, J. Pickands. FINANCE.-Peter White, A. W. Maitland, W D. Rees, E. R. Hall. EXCURSIONS.-W. E. Dickinson, H. A. Burt, A.. Kidder, C. E. Wright. REFRESHMENTS.-J. Q. Adams, H. H. Stafford, Joseph Kirkpatrick, D. H. Bacon. On Tuesday the iron mines in the vicinity of Negaunee and Ishpeming were visited, transportation being provided by special trains on the Marquette, Houghton and Ontonagon Railroad. In the morning the McComber, South Jackson, and Jackson mines were inspected, and in the afternoon the Cleveland, New York, Lake Superior, and Barnum mines. Dinner was provided at Negaunee, and gracefully served by, the ladies of the town. In the evening the first session of the Institute was held in the saloon of the steamer. The President, William P. Shinn, of St. Louis, congratulated the Institute on the happy consummation of the wishes of its members to have a meeting on Lake Superior. After tedious and baffling negotiations arrangements had been com-

Jan 1, 1881

By V. H. Gottschalk

SEVERAL years ago a group in the metallurgical division of the U. S. Bureau of Mines began a study of the application of new developments in physics to metallurgical problems'. Among these developments were the extensions of what may be termed by analogy the "sound spectrum." Electromagnetic waves, from X-rays to radio waves, have been quite thoroughly explored for metallurgical use, but the sound spectrum, extending from low-frequency vibrations involved in certain types of metal failure by fatigue through the range of audible sound to inaudible vibrations having frequencies of many kilocycles, has had only meager consideration from metallurgists. Because of the general interest in the process recently demonstrated by St. Clair3 for flocculating smoke by means of sound waves, this article is written to point out possible applications of sound and supersonic (ultrasonic) waves in the metallurgical industry.

Jan 1, 1937

By J. J. Rutledge

THE first method of working coal mines in the middle western states, more particularly in Illinois, Indiana and Missouri, was by means of the so-called single-entry method. In this method a single main passageway, or entry, was driven in the coal seam. with no parallel passageways, and from this pas-sageway or entry there were turned at intervals sim-ilar cross-passageways or entries, and from these cross-passageways, if the coal seam worked lay fairly horizontal, rooms were turned right and left. These crude methods of working were followed when the com-panies opening the mines were small and of very limited capital, and when the demand for coal was small and irregular. The principal desire was to produce coal in the short-est possible time and at the cheapest price. The chief evil resulting from such method of working was de-fective ventilation, although there were other serious drawbacks. There were then few or no good mining laws and no restrictions on those operating the coal mines. The hours of labor were long, the wages low, and the miners accordingly worked hard. All the coal was either sheared or undercut with a pick by hand. Very little solid shooting and no machine mining was done. What little air entered the mine, openings was introduced through the entries or. headings and thence conducted through the rooms by means of curtains; in many cases, as the workings became more exten-sive, the number of curtains added so materially to the mine resistance that ventilation was extremely in-efficient. Shots were fired by the miners at any time during the working shift and consequently there was more or less powder smoke or fumes in the mine work-ings all day long. Moreover, the working days were much longer than at present. The fine, dry coal-dust falling from the miners' picks while they were shear-ing or undercutting the coal filled the mine atmosphere and was taken into the lungs of the mine employees.

Jan 2, 1927

By E. H. Phillips, A. F. Keenan

6.2-1. Historical Development. Hammering on hand-held drill steel was the earliest type of percussion drilling. It was not until 1838 that Singer developed a steam-operated drilling machine that lifted a drilling bar and let it drop by gravity. J. J. Couch of Philadelphia patented the first percussion drill in 1849. His machine was a steam drill which literally hurled the drill bar at the rock and retracted it by means of a ratcheted wheel. Later J. W. Fowle added automatic rotation of the steel. In 1871, Simon Ingersoll patented a rock drill mounted on a tripod which permitted drilling holes at any angle, vertical to horizontal. Up to the turn of the century, percussion drills in use were piston-type drills. The drill steel was solid and attached to an extension of the drill piston. Hole cleaning was accomplished by the pumping action of the steel in the hole. Down-holes were drilled wet and cleaned with a blow pipe while up-holes were drilled dry, allowing the cuttings to drop out by gravity. The forerunner of our present hammer drill was the free-piston drill which was first patented in 1884, by Sargent. Because solid drill steel was used, it did not successfully clean down holes. J. G. Leyner solved the problem of applying the hammer drill principle to down-hole and horizontal-hole work in 1897. The key was to pass com- pressed air and water through hollow drill steel to clean the hole. Leyner's work on valves and rotation mechanisms increased the blows per minute of hammer drills from 300 or 400 up to 1800 and more blows per minute and made possible the first lightweight drilling machines. The development of automatic feeds followed. 6.2-2. Percussion Drills. TYPES OF DRILLS. There are two types of percussion drills in use today; the piston drill and the hammer drill. In the

Jan 1, 1968

By C. L. Mantell

When considered from the viewpoint of world annual output, tin is one of the rarest metals. Its annual production is exceeded by that of iron, copper, lead, zinc. aluminum, magnesium; probably by that of the ferroalloys of manganese, chromium, and silicon, and possibly by the world production of sodium; while it exceeds only the output of such common metals as nickel, antimony, mercury, tungsten, molybdenum, silver, gold and the precious metals. Cassiterite, or tinstone, until the second World War was the only mineral that was an important source of tin. This mineral is frequently called "tin ore." The use of the term should be restricted to the ore containing the mineral, and not, in addition, to the concentrates of the mineral obtained from the ore or from stanniferous alluvial deposits. There is a general misuse of the term "tin ore" in the Malay Peninsula and adjacent localities, particularly where most of the mineral is obtained from secondary stanniferous deposits. The term "cassit-erite" is exclusively used in mineralogical, geological, and other scientific writings; it is unfortunate that it is not mole frequently used when referring to the occurrence of the mineral on an economic scale. Ores "Tinstone" js a very convenient old English term deserving a more frequent use. Tinstone is a dioxide of tin, or stannic oxide. When chemically Pure, as in the very rare transparent variety, it has a metallic content of 78.6 per cent tin. Frequently, however, the crystals and grains contain appreciable amounts of impurities, chiefly iron and tantalum. The impurities here referred to are those actually in the mineral itself. Tinstone usually has a deep brown or black color with an adamantine luster. Several other colored varieties are known, among them red ruby tin, yellow rosin tin, and yellow wax tin. the names jn each case being descriptive of the mineral's appearance. Ainalite is a variety of cassiterite con-taining almost g per cent of tantalum pentoxide. Sparable tin, tooth tin, and needle tin, as a result of their acute dite-tragonal pyramidal crystalline form, re-ceive their names from their crystallo-graphic appearance. Wood tin is a compact variety of cassiterite composed of radiating fibers resembling dry wood. Toad's-eye tin is a similar variety on a smaller scale in which the fibers appear to resemble the eye of a toad. Stream tin is water-worn tin-stone. Float tin is sometimes employed to describe the cassiterite occurring in soil derived from the weathered surface of a mineralized area. Stannite is an ore of tin of lesser impor-tance than cassiterite. It is a sulphide of tin, copper, and iron, sometimes known as tin pyrites or bell-metal ore. Its chemical com-position is sometimes expressed by the for-mula Cu,S.FeS.SnSz with zinc usually present in varying quantities. The tin con-tent varies from 22 to 27 per cent and there is about 29 per cent of copper, 13 per cent of iron, and 30 Per cent of sulphur.

Jan 1, 1944