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By E. A. Nesbitt

The important permanent-magnet alloys 15 years ago contained carbon and depended upon it for their permanent-magnet properties. In recent years great advances have been made in a number of new alloys substantially free of carbon. These include Remalloy,' an alloy of iron, cobalt, and molybdenum, the various iron-nickel-aluminum alloys of the Mishima2 type, and the more recent Alnico V3 in which the best properties are developed by heat-treating in a magnetic field. The Mishima and the Alnico types of alloys are very brittle and after casting must be ground to size. This article describes a permanent-magnet material4 that can be machined as cast, and when handled with some care can be rolled to thin sheet and drawn to fine wire. Optimum magnetic properties are developed by a simple heat-treatment, and at this time the ductility of the alloy disappears. If the cast alloy is heat-treated without cold-working the mag netic energy product is about 1.0 X 106. This material is called Vicalloy I (pronounced vicalloy, V for vanadium, I for iron, and C for cobalt). When the alloy is first hot-worked and then considerably reduced in area by cold-swaging, drawing or grooved rolling, it is found that after heat-treatment the magnetic energy product measured in the direction of previous extension can be increased to 2.0 to 3.5 X 106. These higher values have been obtained only after reductions in area of 75 to 95 per cent, and since the material hardens considerably during working, the reduction ordinarily can be accomplished only in fine wires, although larger sizes can be reduced by the use of powerful machinery. When the material has been cold-worked in such a manner as to improve its energy product substantially, it is called Vicalloy 11. Commercial use of Vicalloy has been made in the recording of speech. Tape 0.002 by 0.050 in. has been found superior in quality to all others tried, and is now used in the Western Electric Mirrorphone 5 In a variety of forms Vicalloy I or I1 is useful in many laboratory instruments, and in experiments in which the sizes and shapes required cannot be obtained with the other more brittle permanent-magnet materials. In 1936, during a study of other age-hardening magnetic systems, it occurred to the author that some of the iron-cobalt-vanadium alloys might be suitable for permanent magnets. The proportions of iron, cobalt, and vanadium were varied and a range of alloys of particular interest was found, as shown by the indicated area in Fig. I. The limits of this range of composition are 30 to 52 per cent iron, 36 to 62 per cent cobalt, and 4 to 16 per cent vanadium. The compositions indicated by points outside this area were also tested. Preparation and Properties OF Vicalloy I The alloys were usually cast in graphite molds into bars 3/4 in. in diameter and

Jan 1, 1946

By E. A. Nesbitt

THE important permanent-magnet alloys 15 years ago contained carbon and depended upon it for their permanent- magnet properties. In recent years great, advances have been made in a number of new alloys substantially free of carbon. These include Remalloy,l an alloy of iron, cobalt, and molybdenum, the various iron- nickel-aluminum alloys of the Mishima2 type, and the more recent Alnico V3 in which the best properties are developed by heat-treating in a magnetic field. The Mishima and the Alnico types of alloys are very brittle and after casting must be ground to size. This article describes a permanent-magnet material4 that can be machined as cast, and when handled with some care can be .rolled to thin sheet and drawn to fine wire. Optimum magnetic properties are developed by a simple heat- treatment, and at this time the ductility A of the alloy disappears. If the cast alloy is heat-treated without cold-working the magnetic energy product is about 1.0 X 106. This material is called Vicalloy I (pronounced vicalloy, V for vanadium, I for iron, and C for cobalt). When the alloy is first hot-worked and then considerably reduced in area by cold-swaging, drawing or grooved rolling, it is found that after heat-treatment the magnetic energy product measured in the direction of previous extension can be increased to 2.0 to 3.5 X l06. These higher values have been obtained only after reductions in area of 75 to 95 per cent, and since the material hardens considerably during working, the reduction ordinarily can be accomplished only in fine wires, although larger sizes can be reduced by the use of powerful machinery. When the material has been cold- worked in such a manner as to improve its energy product substantially, it is called Vicalloy II. Commercial use of Vicalloy has been made in the recording of speech. Tape 0.002 by 0.050 in. has been found superior in quality to all others tried, and is now used in the Western Electric Mirrorphone In a variety of forms Vicalloy I or II is useful in many laboratory instruments, and in experiments in which the sizes and shapes required cannot be obtained with the other more brittle permanent-magnet materials. In 1936, during a study of other age- hardening magnetic systems, it occurred to the author that some of the iron-cobalt-vanadium alloys might be suitable for permanent magnets. The proportions of iron, cobalt, and vanadium were varied and a range of alloys of particular interest was found, as shown by the indicated area in Fig. I. The limits of this range of com- position are 30 to 52 per cent iron, 36 to 62 per cent cobalt, and 4 to 16 per cent vanadium. The compositions indicated by points outside this area were also tested. PREPARATION AND PROPERTIES OF VICALLY I The alloys were usually cast in graphite molds into bars ¾ in. in diameter and

Jan 1, 1946

By Peter Beardmore, Michael B. Bever

The effects of the temperature of deformation and the degvee of deformation on the annealing spectrum of a Au-Ag alloy have been determined by vesistance measurements. Specimens were deformed in torsion at 4°, 78K and room temperature up to strains nd/l of about 1.0 and were isochronally annealed. Discrete annealing stages similar to those found for pure metals were observed. Stage A occurred below room temperature; the decrease in reszstance associated with this stage increased as the temperature of deformation was lowered or the strain was increased. Stage B manifested itself as an increase in resistance; this is attributed to the restoration of short-range order promoted by vacancy or vacancy aggregate migration. At temperatures above 48S0K, recrystallization or Stage C occurred. Stages A, B, and C in the annealzng curves of this alloy may be considered to correspond to Stages II, Ill, and V, respectively, in the terminology used to describe the annealing spectrum of pure metals. ThE annealing behavior after deformation below room temperature has been thoroughly investigated on pure metals, in particular gold and copper. The occurrence of several discrete stages in the annealing spectrum of these metals has been established, but the interpretation of some of these stages in terms of specific mechanisms is still controversial.' The annealing of alloys deformed below room temperature has been the subject of only a few investigations. In the investigation reported here, a Au-Ag alloy was annealed after deformation at and below room temperature. This continues a research program on the deformation and annealing behavior of Au-Ag alloys.2-8s EXPERIMENTAL PROCEDURE An alloy rod of composition 82.6 wt pct Au-17.4 pct Ag was reduced to wire, 0.0428 in. diam, by swaging and drawing. After a recrystallization treatment, the grain size was 0.031 mm, as obtained from the average linear intercept.7 The ends of wires about 6 in. long were flattened and sealed into short brass tubes with cold setting cement to form the grips of the torsion specimens. The equipment used for deformation has been described elsewhere.6 The specimens were deformed at room temperature, 78", and 4°K to various strains nd/l, where n is the number of turns, d the diameter of the specimen, and 1 its length between grips. The strain rate ?max was 0.1 min-' at the sur- face of the specimen except where noted otherwise. The specimens were annealed isochronally for 30 min at intervals of approximately 30°K from the temperature of deformation to approximately 800°K, except that after deformation at 4°K the lowest annealing temperature was 78°K. A potentiometric method was used to measure the resistance: all measurements were made at 78°K with the exception of some measurements at 4°K mentioned below. Data obtained with a single specimen yielded a complete annealing curve: in several cases duplicate specimens were used to confirm the reproducibility of the curves. Since the surfaces of the specimens were rough after deformation, their diameters could not be measured accurately. The resistance increments after deformation and annealing are therefore reported as percentages of the resistance of the same specimen measured after completion of the annealing, that is, after full recrystallization. The corresponding resistivity values can be calculated by obtaining the effective diameter of a deformed specimen from the ratio of its resistance after recrystallization to the true resistivity, which was determined with a smooth specimen of known dimensions. This method of calculation was used to obtain data shown in several of the figures. RESULTS AND DISCUSSION The isochronal annealing curves after deformation to various strains at 4", 78K, and room temperature are shown in Figs. 1, 2, and 3, respectively. The resistance increment of the as-deformed specimens as a function of strain is shown in Fig. 4. For the specimens deformed at 4°K. values measured at 78°K are plotted with the exception of those for the as-deformed

Jan 1, 1970

By R. J. Wysor

J. S. UNGER, Pittsburgh, Pa.-On page 22 reference is made to 36 carloads .of dust shipped. Did the material in that last sample come from a; furnace running on pig iron, ferro alloys, or spiegel? R. J. Wysor.-Pig iron; we have not made any ferro alloys; or spiegel at Bethlehem in the last 3 years. J. S. UNGER.-DO you use domestic or foreign ores? R. J. WYSOR.-In regular practice, largely foreign ores. J. S. UNGER.-How much per unit does it cost to produce that? R. J. WYSOR.-You might say it does not cost anything; we do not change our blast-furnace practice at all to obtain the dust. Although it has been a profitable byproduct, I would rather not have it unless we could reclaim it on a large scale, as we would have better working stoves. J. S. UNGER.-Does the trade take it as readily as natural salts? W. J. WYSOR.-The fertilizer dealers have been anxious to get it. This did not happen, however, until the war started. J. S., UNGER.-They have been willing to take anything since the war started. R. J. WYSOR.-Yes. However, we could have sold the material before the war; in fact, about 4 years ago, we had a contract ready to sign, but we did not think it would pay us to bother with it then. W. H. Ross, Washington, D. C.-We of the Fertilizer Division of the Bureau of Soils have been particularly interested in Mr. Wysor's investigations on the possibilities of recovering potash from the blast furnace, and we look upon the results he obtained as among the-most important that have yet appeared on the subject of finding new sources of .American potash. About 5 years ago we undertook a corresponding investigation on the recovery of potash in the cement industry. Representative samples of raw mix and ground clinker were collected from the different cement plants in this country with a view to analyzing each sample for potash. With the data thus obtained and knowing the ratio between the raw mix and the cement produced and the output of the latter, we thought it possible to calculate approximately for each plant the quantity of potash that escapes daily from the kilns. After partly completing the work, however, it had to be abandoned for a time. It was again taken

Jan 4, 1917

By E. S. Davenport, R. J. Hafsten, R. A. Grange

The influence of austenite grain size upon the hardenability of steel is now fairly well understood; for a given austenite, increasing the grain size increases the depth of hardening, and, since the latter is related to the fundamental transformation behavior of austenite, it follows that austenite decomposition must, in general, be retarded by increasing grain size. To date, very little quantitative information bearing directly on the effect of austenite grain size upon the progress and result of isothermal transformation has been published. Davenport and Bain,' and Zimmerman, Aborn and Bain2 have shown that the transformation is definitely relarded in hypereutectoid plain carbon steels at temperatures near and above the upper region of rapid transformation (Ar') when the austenite grains are increased in size. More recently, Griffiths. Pfeil and Allen3 investigated the effect of a series of different heating (austenitizing) temperatures upon the progress of isothermal transformation at 1245°F. (675°C.) and 745ºF. (395°C.) in a medium carbon, low-alloy steel; while they reported no measurements of the austenite grain size, their results suggest that increase in grain size retards austenite transformation at 1245ºF. (675°C), but has no appreciable effect at 745°F (395°C.). The present paper deals with the results of a study of the isothermal transformation of austenite in a single commercial alloy steel in which a fine-grained or a coarsegrained state was induced by appropriate selection of austenitizing temperature. The data are presented in the form of isothermal transformation diagrams, which clearly show that coarsening the grains lessens the rate of transformation of austenite to proeutectoid ferrite and pearlite—that is, at temperature levels above about 1000°F. (540°C.)—but is without significant effect at lower temperatures where the transformation product is bainite or martensite. It is to he presumed that the foregoing statement would be valid, at least in principle, for many other grades of steel; it confirms again that the mechanism of transformation to a pearlitic structure is fundamentally different from that to an acicular structure. A number of related observations were made, which seem to throw some light on the transformation process as it takes place in alloy steels, particularly at temperature levels in the vicinity of 1000ºF. (540°C.), where the transition from lamellar to acicular structures occurs. These data are discussed briefly in the belief that they may lead to a clearer understanding of this aspect of the subject. Material and Experimental Procedure The material investigated was a cornmercial grade of S.A.E. 4140 steel, the composition of which was as follows: 0.37 per cent C, 0.77 per cent Mn, 0.98 per cent Cr and 0.21 per cent Mo. It was hot-rolled to a 1 1/8-in. round bar and normalized by air-cooling from 1800°F. (980°C.).

Jan 1, 1941

By R. J. Hafsten, E. S. Davenport, R. A. Grange

The influence of austenite grain size upon the hardenability of steel is now fairly well understood; for a given austenite, increasing the grain size increases the depth of hardening, and, since the latter is related to the fundamental transformation behavior of austenite, it follows that austenite decomposition must, in general, be retarded by increasing grain size. To date, very little quantitative information bearing directly on the effect of austenite grain size upon the progress and result of isothermal transformation has been published. Davenport and Bain,' and Zimmerman, Aborn and Bain2 have shown that the transformation is definitely relarded in hypereutectoid plain carbon steels at temperatures near and above the upper region of rapid transformation (Ar') when the austenite grains are increased in size. More recently, Griffiths. Pfeil and Allen3 investigated the effect of a series of different heating (austenitizing) temperatures upon the progress of isothermal transformation at 1245°F. (675°C.) and 745ºF. (395°C.) in a medium carbon, low-alloy steel; while they reported no measurements of the austenite grain size, their results suggest that increase in grain size retards austenite transformation at 1245ºF. (675°C), but has no appreciable effect at 745°F (395°C.). The present paper deals with the results of a study of the isothermal transformation of austenite in a single commercial alloy steel in which a fine-grained or a coarsegrained state was induced by appropriate selection of austenitizing temperature. The data are presented in the form of isothermal transformation diagrams, which clearly show that coarsening the grains lessens the rate of transformation of austenite to proeutectoid ferrite and pearlite—that is, at temperature levels above about 1000°F. (540°C.)—but is without significant effect at lower temperatures where the transformation product is bainite or martensite. It is to he presumed that the foregoing statement would be valid, at least in principle, for many other grades of steel; it confirms again that the mechanism of transformation to a pearlitic structure is fundamentally different from that to an acicular structure. A number of related observations were made, which seem to throw some light on the transformation process as it takes place in alloy steels, particularly at temperature levels in the vicinity of 1000ºF. (540°C.), where the transition from lamellar to acicular structures occurs. These data are discussed briefly in the belief that they may lead to a clearer understanding of this aspect of the subject. Material and Experimental Procedure The material investigated was a cornmercial grade of S.A.E. 4140 steel, the composition of which was as follows: 0.37 per cent C, 0.77 per cent Mn, 0.98 per cent Cr and 0.21 per cent Mo. It was hot-rolled to a 1 1/8-in. round bar and normalized by air-cooling from 1800°F. (980°C.).

Jan 1, 1941

By E. H. Bunce

CONTINUED progress in zinc metallurgy has been shown during 1933 by the adoption of new methods as well as the modernization of old processes and equipment, and by the initiation of new fields of activity for future advancement. The use of suspension roasting continued to grow as its advantages and adaptability became increasingly, apparent. The process developed by the National Smelting Co., Ltd., several years ago, of completely roasting on large sintering machines with utilization of the gas for acid manufacture has worked so successfully that an additional machine was installed during the year. At both the Swansea and the Avonmouth Works all of the ore for smelting is now roasted on the large sintering machines, thereby completely eliminating the old hearth-roasting furnaces. Work continued on obtaining partial purification of zinc ores from lead and cadmium by close control of conditions on the sintering machine, and in a few instances by chlorine additions to the ore before sintering. Ores so treated were either partially roasted or com-

Jan 1, 1934

By A. E. Outerbridge

It has been generally accepted as a fact that cast-iron, under the influence of repeated shocks, becomes brittle, and will finally break under a blow which otherwise it would have withstood. It will probably surprise metallurgists, therefore, to learn that experiment disproves the supposed fact, and establishes exactly its opposite. The result of about a thousand tests of bars of cast-iron of all grades, from the softest foundry-mixtures to the strongest car-wheel metal, enables me to assert with confidence that, within limits, cast-iron is materially strengthened by subjection to repeated shocks or blows. It is very well known that the usual process of annealing castings—such, for example, as car-wheels—increases their strength by relieving cooling-strains. But it is not well known (if known at all prior to this announcement) that the molecules of cast-iron are capable of movement—for they do not touch each other*—without the necessity of heating the casting, and that they can thus rearrange themselves in comfortable relation to their neighbors, and relieve the overcrowding near the surface of the casting. In more technical words, a molecular annealing may be accomplished at ordinary temperatures which will release the strains in the castings, precisely as does annealing by slow cooling in heated pits or ovens. A statement so surprising should not be made without sufficient data to establish its correctness beyond cavil, since it is contrary to former

Jan 1, 1897

By J. F. Wolff, Anson A. Betts

The following correspondence relating to a paper bearing the above title, presented by J. F. Wolff, at the New York meeting in February, 1917, and published in the Transactions, Volume LVI, page 142, has passed between the author of the paper, and Mr. Anson G. Betts, and is interesting, although it was received much too late for incorporation in its proper place in Volume LVI. Anson G. Betts, Asheville, N. C.—1. I should like to ask Mr. Wolff if he finds from analysis of the iron formation and of the iron ore, and from the relative amounts of each in each unit area of the formation, unleached and after leaching, that the iron remains entirely insoluble and the total quantity still remains present; or whether he finds that some of the iron is removed, or possibly even added by deposition from the water passing through the formation. 2. The water that passed into the iron formation had to go somewhere; was it absorbed by underlying formations through hydration, or, after passing through the ore formation, did it come to the surface in springs at a lower elevation, or how did it escape from the ground? 3. I should like to ask Mr. Wolff whether he finds that the iron formation in the sedimentary series does not come next to the quartzites and generally between the quartzites and slates. J. I?. Wolff, Duluth, Minn.—1. In common with others, you appear to have some hesitancy in accepting the fact of the removal, by solution, of the enormous quantity of silica which has been leached out of portions of the Biwabik iron formation, thus forming orebodies of merchantable iron ore. I believe that even Dr. Waldemar Lindgren once hesitated to accept this fact. However, the evidence is so simple and absolutely conclusive that the fact is established beyond all question. At the contact of orebodies with their rock walls, the bands of iron ore in the orebody can be seen in contact with the corresponding bands of original iron oxide in the rock wall, and the chert layers in the rock wall can be seen to give place to fine granular material (fine silica and iron oxide) and pore space. This is especially noticeable where slumping at the rock walls has not been so great as to displace the layers in the orebody from their contact with their corresponding layers in the rock wall. Although complete analyses of the entire original rocks in the iron series have not been made in any place, to my knowledge, from the best data at hand as to the average analysis of the Biwabik series and the

Jan 1, 1920

By E. Gregory, A. Coucoulas

Carbm dioxide, which exists metastably as a constantly subliming molecular solid in a normal room-temperature environment, has been shown to exhibit many microstructural features which are similar to those observed in metals and ceramics at temperatures approaching their melting points. An examinution has been made of some of the factors affecting a brittleness condition known as "smzdiness" which occurs in solid carbon dioxide. It has been shown to be highly dependent on manufacturing and storage conditions and is thought to be a marked intergranu-lay brittleness which results from a combination of excessive grain growth and a concentration of gas-filled pores at the grain boundaries. In the course of an investigation carried out to explain certain physical and mechanical properties of solid carbon dioxide, observations were made of the microstructure and fragmentation of samples after fabrication and storage under varying conditions. Many similarities between the structures of solid carbon dioxide observed under ambient conditions and those existing in metal and ceramic systems at temperatures approaching their melting points have been observed. There are, however, important differences between solid carbon dioxide and the common metallic and ionic solids which result primarily from the differences in the nature of the bonding forces. Despite these differences, the relative ease with which certain microscopic observations can be carried out, may make solid carbon dioxide a useful material model for the physical metallurgist and the ceramist. It could also prove a valuable material for educational purposes where it is required to illustrate grain phenomena which normally can only be seen with the aid of a high-temperature microscope, and after prolonged chemical or thermal etching.

Jan 1, 1963

By Earl S. Bardwell

The structural relations existing between cuprous oxide and copper were first systematically studied by Heynl; who suggested that a study of the microstructure of refined copper might be substituted for the analytical methods in vogue for determining the oxygen content of copper coming from the refining furnace. Hofman, Green and Yerxa,2 in their paper A Laboratory Study of the Stages in the Refining of Copper, working along the lines suggested by Heyn, showed that a study of the microstructure could be made to yield a correct estimate of the oxygen content of refined copper. In order to determine the oxygen content of the specimen of refined copper under examination a photomicrograph was first made. From the relative areas of copper and eutectic, the percentage of cuprous oxide and the corresponding percentage of oxygen were then readily calculated. It was found that the values for oxygen thus obtained corresponded closely with the analytical results. With the idea of utilizing this method of determining the oxygen content of each charge dipped from the refining furnaces at the Boston & Montana Reduction Plant, the physical testing laboratory was equipped with suitable apparatus for carrying out the work. It may be of interest to describe certain of the methods which have been worked out in this connection and give such data as have been obtained bearing on the effect of the oxygen content of refined copper upon its conductivity. Apparatus.—For the benefit of those who may be unfamiliar with metallographical apparatus and methods and may be interested to know what equipment is required, a few words with regard to the apparatus are in place at this point.

Jan 1, 1914

By Francis Church Lincoln

I. Situation and Surroundings, The Promontorio mine is situated at the northern end of the Sierra San Francisco de Coneto, in the town of Promontorio, Partido of El Oro, State of Durango, Mexico. As shown in the sketch-map, Fig. 1, the nearest railroad station is Chin-acates on the Mexican International Railroad, 82 miles north of the city of Durango. The mine is 16 miles north of the sta-tion by air-line. It is reached by means of a good wagon-road which first crosses the Guatimapé Plain, passing the ranches of San Antonio and San Julian, to Estacion—a distance of about 15.5 miles—and then entering the mountains crosses the Sierra to Promontorio—a further distance of 11.5 miles— making in all a distance of 27 miles by road from railroad to mine. Promontorio is just beyond the summit of the range, at an elevation of about 8,000 ft. above sea-level, or 1,350 ft. above the Chinacates station. The Castillo de San Francisco, the highest peak in the Sierra, has an altitude of 10,000 ft., and the Promontorio road crosses the summit of the ridge at an elevation of 9,000 ft. by a pass just below this peak known as the Puerto del Almagre. The Promontorio mill is situated at Santa Inés, 2 miles by tram or 3 miles by wagon-road to the north of Promontorio and about 600 ft. lower. The Sierra San Francisco de Coneto decreases in height towards the north and west till it comes to an end at the Mel-chor Arroyo on the ranches of Melchor and Ramos. Beyond this arroyo another range, the Sierra de la Candela, begins. In the vicinity of the Promontorio mine the hills are very rugged and the surface is furrowed by ravines which contain running streams during the rainy season-—July, August and

Jan 1, 1908

By H. A. Coy, H. B. Henegar

The Mascot mines of the American Zinc Co. of Tennessee are situated in the Holston River valley, in Knox County, Tennessee, about 13 miles (20.9 km.) east of the city of Knoxville, and form a property of three operating shafts and one open pit. A second open pit is located at Jefferson City about 16 miles (25.8 km.) east of the Mascot mines. Geology Topography.—The principal topographical features of the region within which the zinc deposits occur is a series of parallel northeast and southwest ridges which reach altitudes of 200 to 400 ft. (61 to 122 m.) above the valley. These ridges are formed of resistant formation such as sandstone, quartzites, etc., while the valleys are occupied principally by limestone, including Knox dolomite, and by shale and other formations subject to quick erosion. The Holston River valley is wide and open with a rolling surface. Sink holes are common to the limestone portion, the general aspect of the valley being that of well-rounded hills with low intervening valleys superimposed upon which is a characteristic sink-hole topography. General Geology.—According to Keith, the rock formation of the area extends from the lower Cambrian into the Silurian. The region has undergone severe deformation with hcavy faulting, the underlying Cambrian having been brought to the surface by a series of low angle thrust faults, the strike of the faults and formations paralleling the general northeast and southwest direction of the topography and dipping at varying angles to the southeast. In general, the Cambrian quartzites, sandstone, etc., occupy the ridges while the Cambro-Si urian dolomites, limestone and shales occur principally in the valleys. Of the latter, the Knox dolomite is of particular interest to this paper in that it is the ore carrier in the Mascot area. The ore is associated with more or less irregular breccia zones, the degree of brecciation varying from a fine crushing to a breaking that involves blocks of large size. The breccia zones

Jan 1, 1918

By Alfred Boyles

The experiments described below are a continuation of work on the graphitization of cast iron conducted as part of the program of fundamental research at Battelle Memorial Institute. In previous work it was found that melting in hydrogen increased the amount of eutectic carbide appearing in certain alloys and in others produced marked changes in the size of the graphite flakes. These effects seemed to be closely related to the amount of sulphur and manganese present in the material studied. Iron-carbon-silicon alloys did not respond to hydrogen in the same manner as cast iron and there was no evidence to show that hydrogen was able to stabilize the carbide in such alloys unless additions of sulphur were made. The two alloys examined contained about 2 per cent of silicon. The present paper is concerned with alloys of lower silicon content and describes the structural changes produced by melting in various atmospheres at pressurcs ranging from a partial vacuum up to 300 lb. per sq. inch. Experimental Method The experimental technique was similar to that previously employed, so that direct comparison might be made with earlier work. Alloys were

Jan 1, 1939

By Alfred Boyles

The experiments described below are a continuation of work on the graphitization of cast iron conducted as part of the program of fundamental research at Battelle Memorial Institute. In previous work it was found that melting in hydrogen increased the amount of eutectic carbide appearing in certain alloys and in others produced marked changes in the size of the graphite flakes. These effects seemed to be closely related to the amount of sulphur and manganese present in the material studied. Iron-carbon-silicon alloys did not respond to hydrogen in the same manner as cast iron and there was no evidence to show that hydrogen was able to stabilize the carbide in such alloys unless additions of sulphur were made. The two alloys examined contained about 2 per cent of silicon. The present paper is concerned with alloys of lower silicon content and describes the structural changes produced by melting in various atmospheres at pressurcs ranging from a partial vacuum up to 300 lb. per sq. inch. Experimental Method The experimental technique was similar to that previously employed, so that direct comparison might be made with earlier work. Alloys were

Jan 1, 1939

By Elmer W. Pehrson

The term "survival" in the title means the preservation of a society in which men are free from the political and economic restraints that characterize totalitarian systems, be they communist, socialist or facist. It means the ability to withstand the enemy's offensives in the fields of propaganda, commercial competition and, if necessary, war. The temptation to substitute "victory" for "survival" is great but a realistic appraisal of the creeping socialism and demagoguery that pervade our time indicates that we may have to be content with survival in status quo. "Mineral strength" means assurance that adequate supplies will be available to meet all the contingencies of cold and hot wars. The overall mineral position of the U. S. viewed in the light of these premises is far from secure. It is true that we are the leading producing and consuming nation of the world, but the Soviet Union is gaining and the Sino-Soviet Bloc confronts us with a sobering potential. The emergence of the Common Market in Europe as an economic and political unit places a third independent entity into the competition. Our total mineral output continues on an up- ward trend but the reverse is true in certain strategic commodities. Moreover, consumption is moving ahead faster than production so that there is increasing dependence on imports which has significant adverse geopolitical connotations. There is widespread belief that our resources can at least maintain present levels of self-sufficiency during this critical period in world history, but social dreamers, the labor monopoly, and trade and taxation policies have discouraged aggressive activity in exploration and development, and access to essential foreign sources is threatened by a variety of circumstances. Our stockpiles, belatedly built up to achieve minimum protection against shortages in time of war, are under. political attack and threatened with partial destruction on the basis of what are at best uncertain assumptions regarding the new: look of global warfare.

Jan 11, 1962

By T. R. Braithwaite

The brief comments made in this chapter deal mainly with shaft sinking, but don't assume that freezing techniques apply only to shaft sinking. They can be used on tunnel work, on such things as liquid gas storage in sediment, and I think you will probably see other applications for it as we go along. The method was first developed in 1883 and was used to sink shallow shafts through water-bearing overburden in Germany and in England. One of the early shafts was in Germany and was sunk by freezing to 310-ft depth. The project required 17 months for drilling, roughly 5 1/2 months for freezing, and another 7 months for sinking, giving an average progress of 10 ½ fpm. Fortunately there have been numerous improvements and new developments in this technique through the years. With equipment and techniques available today, we can take a 20-ft-diam shaft down through 2000 ft of water-saturated overburden and the time schedule runs roughly 4 months for site preparation, freeze-hole drilling, installing the casings, and setting up the plant; 4 ½ months for freezing; and 6 months for excavating and installing permanent linings. This gives a progress rate of about 140 fpm, on average. I might qualify that a little in that the special linings that are required for some formations can affect the time. If it's straightforward sinking where one can use a heavy concrete lining, up to 630-640 fpm may be achieved in a shaft; but with special cast-iron tubbing or types like that, 5 fpd is pretty good progress, so the lining does affect the time. The freezing method is used mainly for sinking shafts through unstable water-bearing formations which cannot be grouted either effectively or economically and which are too deep to enclose in pile casing. Even with overburden, grouting methods available today can handle roughly 100 lb water pressure; in the range of, say, 100 to 150 ft from the surface, it's very often best to grout 40 or 50 ft. You normally drive a pile casing and go through it. Below that range, freezing is very often the economical

Jan 1, 1970

By Edgar Kidwell

To any one acquainted with the practical conditions surrounding the mining engineer and mine-manager, especially in this country, the presentation to the American Institute of Mining Engineers of a paper on the above subject will need no explanation. The members of this profession are continually called upon to design and erect, both above and underground, structures which involve the use of beams. Not to mention the various buildings connected with large mining operations, I need only refer, in support of this statement, to trestles, derricks, headworks, etc., on the surface, and to timbered stations and other spaces of large span in the mine-workings. Notwithstanding the rapidity with which iron and steel are replacing wood in the construction of large buildings, there will always be cases in which the use of metal will be unadvisable. Especially will this be true in districts remote from large cities. Works of temporary character will continue to use timber. High freight-charges, the liability of delays in delivering iron, and the temporary character of many of the structures, will for many years to come make it advantageous for the mines west of the Mississippi and on Lake Superior to construct their buildings almost exclusively of wood. The timber-resources of the country are decreasing so rapidly that already the engineer finds difficulty at times in obtaining beams of large size. This difficulty will steadily increase, and will force the constructor to resort more frequently to built-up beams, such as have long been used in Europe, owing to the difficulty of obtaining there such large sizes of timber as have

Jan 1, 1898

By Lucien Eaton

The use of filling in mines is less common in the United States than it is in Europe, where in some places it is required by law. In most cases the filling is placed by hand, and the material used for this purpose is the waste from development and that sorted from the ore in the stopes. When these sources provide an insufficient supply, additional rock must be quarried on surface or mined underground, or some other material must be used. In different parts of the world sand, clay, gravel, culm, granulated slag, mill tailings, and even ashes, have been used as filling material in place of or in conjunction with rock. Of all the materials used for filling the best is probably clean sand. Gravel, finely crushed rock, granulated slag and coarse mill tailings are almost as good, and the methods used for placing and confining sand will apply equally well to any of these. The advantages of sand are its comparatively slight compressibility and the ease, economy and convenience with which it may be placed. On account of the voids, which necessarily occur in fills made of coarse waste, such fills will compress 10 to 25 per cent before they develop their full strength, whereas clean sand seldom compresses more than 5 per cent. Sand is especially desirable when practically complete filling is required, and sand derived from mill tailings, especially when not thoroughly cleaned, has been remarkably effective in sealing off and extinguishing mine fires. When natural sand is available on surface, or when it can be obtained from the mill tailings or tailings dump, the cost of using this material for fill will probably be considerably less than that of rock. In this paper it is not proposed to discuss all methods of filling, but to describe some of the methods used for placing sand fill and to make a brief comparison of their merits. Methods of Placing Sand Sand may be transported and placed underground by several methods, which may be classified as follows: 1. By Hand.—The sand, which must be comparatively dry, is taken down the shaft in cars on cages and is distributed to its destination in these cars, or it is dumped down raises and is drawn off and distributed by means of cars, wheelbarrows or scrapers.

Jan 1, 1932

By C. E. Ells, A. Sawatzky

The effect of neutron irradiation on tensile properties of the Zr-2.5 wt pet Nb-0.5 wt pet Cu alloy has been evaluated for integrated neutron fluxes up to 3 x 1020 n per sq cm (E > 1 Mev). Specimen temperature during irradiation was normally 300°C. The material was studied both in annealed and in quenched and aged conditions. When the alloy (fab-ricatedfrom sponge zirconium) is quenched from a temperature =40°C below the a + ß/ß transformation and aged 6 hr at 535oC, neutron irradiation up to the maximum studied has little effect 071 reduction in area, although there is a drop in uniform elongation and the yield strength is increased by = 25 pct. Conversely, irradiation of the alloy in an annealed condition can result in much greater changes in properties, with yield-strength increases of up to 200 pet. The dose dependence of irradiation hardening obeys the saturation equntion proposed by Makin and Minter to explain hardening in copper and nickel: Act = C[1 - exp(-Døt)/1/2 A rnodel is proposed to explain the effect of niobium content and metallurgical condition on irradiatiotz behavior. THE Zr-Nb alloys form a class of material susceptible to marked strengthening by quench and age heat treatment. With niobium concentrations as low as 2.5 wt pet, strengths can be developed which are double those of annealed zircaloy-2.1 Since the neutron-capture cross section of the Zr-2.5 wt pet Nb alloy is nearly identical to that of Zircaloy-2, significant gains in power-reactor neutron economy could be obtained by replacing stressed in-reactor components of Zircaloy-2 with the heat-treated Zr-Nb alloy. When the solution heat-treatment temperature is in the high (a + ß) phase, then the tensile properties of the quenched (and aged at 500°C) material have been shown to be relatively insensitive to neutron irradiation.1-3 Addition of small quantities of copper to the binary Zr-2.5 wt pet Nb alloy gives a useful reduction to the corrosion rate in air and carbon di- oxide,&apos; and a ternary alloy of composition Zr-2.5 wt pet Nb-0.5 wt pet Cu was chosen for one component in the Douglas Point Reactor. This application utilizes both the corrosion resistance to a moist air-carbon dioxide environment and the strength developed by a quench and age heat treatment. By suitable choice of solution heat treatment and aging temperatures, tensile properties of the ternary alloy can be made nearly identical to those considered as optimum for the binary alloy. One effect of the copper addition, however, is to give marked changes in the aging kinetics of the alloy.&apos; For this reason, it appeared that neutron irradiation might promote overaging in the ternary alloy, particularly at the elevated service temperature (=300°C). This paper describes the effect of neutron irradiation on the tensile behavior of the Zr-2.5 wt pet Nb-0.5 wt pet Cu alloy in several metallurgical conditions pertinent to its use as a reactor material. The metallurgical conditions included those for which aging occurs in the unirradiated material, and fully annealed conditions for which a higher degree of thermal stability could be expected. 1) EXPERIMENTAL Two batches of alloy were used, both made from sponge zirconium. The fabricator&apos;s analysis of principle constituents showed no significant difference between the two batches, Table I. The rod material was rolled to 1.5 in. diam, and then swaged to final sizes of 0.5 to 0.375 in. diam at nominal temperatures of 785" and 625°C for the AM and AS batches, respectively. Subsequent hydrogen analyses at CRNL confirmed that the hydrogen concentration of the as-received rod was indeed <20 ppm. However, it was found that the (a + ß)/ß transus for the AM material was approximately 25°C lower than that of the AS material, indicating rather more difference in oxygen concentration than given in Table I. Except for a small difference in yield-point behavior, the tensile prop-

Jan 1, 1965