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By C. D. Hall

This paper may be divided into two main parts: (1) analysis and data to show that Eq. 6 adequately correlates the authors' experimental data, and (2) the assertion that Eq. 20 "should permit scale-up with data taken from one pipe diameter for Newtonian, inelastic non-Newtonian, and viscoelastic fluids, such as dilute polymer fracturing fluids, which produce considerable pressure reductions." The authors might well recommend that this broad grouping of fluid types could be correlated by using Eq. 6 (requiring data from at least two pipe diameters). On the other hand, Eq. 20 is only shown to be adequate for conditions within the range of the present data set. Specifically, predictions by Eq. 20 for diameter scale-up to casing sizes would give larger deviations than implied in Table 2, and scale-up for some other fluids that give large drag reduction could be grossly in error. The description of a class of fluids "which produce a diameter family of straight parallel lines on a log (d?p/4L) vs log (8 v/d) plot. . ." defines a necessary condition for using Eq. 6; i.e., that s shall be constant for each fluid. The proposal that Eq. 20 is applicable to turbulent flow of such fluids is equivalent to saying that the spacing of these parallel lines, with A being constant, will be found to correspond to m = -1.20 for all such fluids. Table 1 shows the values of m derived from data on 16 non-Newtonian fluids. The key statement of this paper is that the diameter exponents "do not vary significantly from . . . -1.20." In statistical terms, this says that the m value for each fluid, which was obtained from all the measurements made on that fluid. has not been shown to be different from the arithmetic mean of the m values for the 16 fluids tested. This implies that the group mean, -1.20, is a more reliable value to use for an individual fluid than is the m value derived from the data on that fluid alone. No statistical test is described to support the key statement that the diameter exponents do not vary significantly from -1.20. Such a test would have to take into account that each individual m value is shown to correlate the pressure gradients for its fluid, with only about 3 percent standard deviation over the diameter range covered. That is, the m value is not the result of a single independent measurement. Thus, it would not be sufficient, or valid, to compare the deviation of one of the m values with the variance of the 16 values of m about their mean. An alternative interpretation of the key statement is that the diameter exponents do not vary appreciably from -1.20; i.e., that using -1.20 does not cause serious inaccuracy. Table 2 seems to be offered in support of such an assertion. However, such a statistical treatment (1) is unnecessary and (2) cannot lead to any valid scale-up generalization. The amount of error introduced by using a 1"wrong" value of diameter exponent — i.e., -1.20 instead of m — is determined by Eq. 6. The ratio of the pressures predicted by Eqs. 6 and 20 for scale-up from ds in small pipe to d, in casing is The pressure for 30-percent calcium carbonate slurry (m = -1.112) in 10-in. ID pipe would be predicted 30 percent higher by Eq. 6 than by Eq. 20, if based on tests in 0.5-in. ID pipe. The data set tested in Table 2 represents only a limited sample of pipe diameters (ratio of about 4:l) out of the population of diameters that would

Jan 1, 1970

By B. M. Larsen, T. E. Brower, J. W. Bain

A mass of circumstantial evidence is presented to indicate that the main source of alloy losses in open-hearth tapping is oxidation by air, with the steel apparently reacting with an amount of oxygen equivalent to about 30 times its own volume of air. The effect is erratic from heat to heat, depending largely on turbulence and distance of free fall of the stream of liquid metal. THIS paper reports another phase in a general study of oxidation in the open-hearth, various aspects of which have already been discussed in previous papers.1,2,3 It is based on experiments conducted on commercial, basic open-hearth furnaces at various times when opportunity offered, beginning about 1938, in an attempt to determine the mechanism and measure the amount of air oxidation during the flow of the tapping stream through the air into a ladle. This effect is closely connected, not only with alloy losses and control of chemical analysis, but possibly with various questions regarding inclusion content and steel quality and with a true picture of the deoxidation of steel in general. Thus it is believed that discussion of a large part of the results to date may be of assistance to others who are studying problems related to deoxidation or to steel cleanliness and quality. The literature reveals that strangely little attention has been devoted specifically to the effect of pouring steel through open air. Bardenheuer and Henke4 in 1939, in a paper devoted largely to overall losses of manganese in the basic open-hearth, reported that for a number of heats tapped into a tilted ladle held just beneath the runner so that the maximum distance of drop of the stream through the air was held to less than about 30 in., there was in most cases almost no loss of manganese from furnace to ladle. Hultgren,5 in 1945, showed that in high-carbon basic electric steel deoxidized in the furnace and containing no large inclusions as it left the furnace, large silicate inclusions, often rich in manganese oxide, were present in samples dipped from the pool in the ladle; also that the rise in content of large inclusions (above 0.01 mm dim) was greater when the metal stream was made to spray or flow in a turbulent manner. Our interest in this phase of oxidation in the open-hearth was first aroused by a study of alloy efficiencies on ladle additions. The frequency curves of manganese efficiency (net recovery of metal added in ladle) given in fig. 1 are of interest in this connection. Lowest, and also most variable (47 to 95 pct), recovery was in low-carbon heats having no coal additions to the ladle, progressing upward to a maximum average and least variable (82 to 97 pct) recovery in high-carbon heats killed with aluminum and silicon. Both coal additions and higher carbon contents in the tap stream, as well as additions of silicon and aluminum, help to lower the amount of manganese loss. But the most interesting point is the amount of manganese oxidized in many heats tapped at 0.50 to 1.06 pct carbon. It has been shown in a previous paper3 that the amount of oxygen in the tap stream in such heats is very small, usually below 0.01 pct, too small to oxidize any appreciable amount of manganese. Also, the fact that manganese should be oxidized at all in a metal solution containing such more stable oxide-forming elements as aluminum and silicon is an indication of some rather intense oxidizing effect such as could be caused by reaction with the air during ladle filling. Oxygen Balances from Tap Stream to Teeming Stream: Data in the form of alloy efficiencies, such as those shown in fig. 1, are not a proper measure of such a general oxidation effect. Having available

Jan 1, 1951

By J. E. Forciea, O. E. Palasvirta, L. G. Hendrickson

AH pilot and commercial plants working with Mesabi Range taconite employ wet magnetic separation. Progress is being made with a dry magnetic process, but this has not yet been applied to taconite except in the laboratory and pilot plants. Flowsheets in all five plants are similar, including multiple stages of grinding, each followed by magnetic separation, which rejects a finished tailing. The flowsheet in Fig. 1 is used in the preliminary and commercial plants of the Erie and Reserve mining companies and in Unit C of Oliver's Pilotac plant. At Erie the desliming operation is omitted. In the Reserve plants two ball mills are used with each rod mill. Pilotac uses flowsheet 2 in Unit A-B and has also tested flowsheet 3. Principal differences in the three flowsheets are the number of grinding stages and the type of roughing. The terms open-circuit roughing and closed-circuit roughing are best defined by the diagrams. Special Test Data Given in Table I: For the Erie and Reserve commercial plants, Table I reflects routine conditions. Pilotac, the experimental plant, has been run with several flowsheets, including those followed at Erie and Reserve's commercial operations. Pilotac data for these last two flowsheets are similar to commercial plant results and are not repeated in Table I; statistics are given, however, for special test conditions. using other flowsheets. when the objective was to 'to extra-grade concentrate, Variations Among Taconites: Although crude ore tributary to these plants is generally classified as taconite, there are important differences in mineralogy and fineness of dissemination.

Jan 1, 1959

By SAMUEL GOMPERS

THE name engineer makes a very strong appeal to one who appreciates the mechanism underlying the fabric of our civilization. Engineers are scouts of civilization. We send them ahead into the lone 'places-the wilderness, the jungles, the great watery expanses, to build the highways necessary for civilized man. The engineers must deal with Nature, with that mysterious dynamic thing we call "force," with materials. It is their function to direct the human activity necessary to coordinate these forces and material in order to make them serve the needs and aspirations of men. Because of my high conception of the engineering profession I was glad to accept the invitation to address The American Society of Mechanical Engineers to voice my understanding of the possibilities of your work as engineers of industry, and to suggest what seems to me the responsibility of the-engineer to the whole modern industrial system.

Jan 1, 1921

By F. L. Bosqui

NO metallurgical process developed in the last half century has been more widely advertised to both technologists and lay- men, or has done more to promote efficiency and economy in the extraction of the valuable portions of ores than has the flotation process. Practically everybody has heard of this strange procedure whereby the heavy portions of an ore are made to float while the light parts sink. Some- times it is called froth flotation, the mineral-bearing froth being from the first a distinguishing characteristic. Many times it is called oil flotation, because a thin film of oil was commonly applied to the particles to be floated to make them adhere to the bubbles that rise through the pulp to form the surface froth. Oil, though commonly used, is not, however, necessary for this purpose, which is one of the facts that has been learned as the process has been developed.

Jan 1, 1940

By Theodore W. Robinson

WHEREVER the amount of work renders it practicable the plan of using permanent standard solutions, in connection with the colorimetric carbon test, affords such manifold advantages that it is to be strongly recommended. That it has not attained a wider and more general application, is mainly due to the fact that, as the method is generally employed, the difficulty attending the production of the colors, and their doubtful stability when produced, have been only too evident to those who have undertaken their composition. The old method of using standard solutions made from sugar, coffee, etc., has always been hampered by the tendency of the colors to change upon exposure to the light, and the consequent liability to serious error, unless they are closely watched. Appreciating these difficulties, while recognizing the desirability of permanent colors, Mr. Magnus Troilius, at the suggestion of Prof. F. L. Erkmann, investigated the properties of cobalt, copper and ferric chlorides, with the view of determining their efficacy in the production of standard solutions. His results, as obtained, seem to have been satisfactory, but his treatment failed to eliminate many of the objections that have rendered the use of organic colors undesirable. The

Jan 1, 1888

By E. J. Schmitz

Coming from San Antonio, Texas, and following the Galveston, Harrisburg and San Antonio Railroad westwards, one enters soon the Cretaceous formation, which forms a belt of several hundred miles, extending westwards to the boundary of Arizona and across the Rio Grande into the State of Coahuila, Mexico. The members of this formation are very numerous and in petrographical character very diverse—from a whitish or bluish, slaty, impure limestone to a hard, beautiful blue-and-red striped, and a compact heavy-bedded,

Jan 1, 1885

By J. M. Hodge, H. M. Reichhold, R. D. Manning

The work reported in this paper represents the first of a series of investigations of the factors governing notch toughness in ferritic materials. This paper is concerned with two of these factors, namely, the effect of ferrite grain size, and the effect of an alloy content of 3.64 pct nickel. Every effort has been made to hold other variables constant in order to isolate the effects of these two. The compositions chosen for study were 0.02 pct carbon in order to eliminate the variable of carbide distribution, one steel being a plain carbon steel and the other alloyed with 3.64 pct nickel. Both steels were fully killed with silicon, without an aluminum addition, so that the variable of deoxidation practice was held constant. Finally, all samples were water quenched from 1200°F and tempered 24 hr at 300°F in order to hold the quench aging variable constant and to decrease the tendency for grain boundary carbide precipitation. The ferrite grain size was varied by heat treatment over the range of A.S.T.M. grain size numbers of about 2 to 6 in each steel so that the effect could be evaluated individually and the notch toughness of each steel could be compared at comparable ferrite grain sizes. Materials and Experimental Procedure MATERIALS The materials for this investigation were obtained from Battelle Memorial Institute as 250 Ib induction melts which were forged into 134 in. square bars and then rolled into 0.6 in. square bars. Both steels were deoxidized with silicon, the aluminum content being held to a minimum. Check analyses of these materials are shown in Table 1. HEAT TREATMENT FOR GRAIN SIZE The grain size was varied by varying both the cooling rate and the austeni- tizing temperatures. The heat treatments used and the corresponding grain size values are tabulated in Table 2. A semicontinuous network of grain boundary carbide was observed in the microstructure of both the plain carbon and nickel steels in the as rolled condition and an additional heat treatment was necessary to eliminate this variable. Therefore, all samples were water quenched from 1200°F and tempered 24 hr at 300°F as a final treatment before testing. This heat treatment served to eliminate to a great extent the grain boundary carbide network and to hold the quench aging effect constant. IMPACT TESTING Standard keyhole Charpy impact tests were machmed after heat treatment. A bath of acetone and dry ice was used for refrigeration of the samples down to temperatures of —94°F (—70°C) and a bath of either methyl-cyclohexane or isopentane, cooled by

Jan 1, 1950

By Gorr W. W., Wyche E. H, R. Smith

The combination of high strength and corrosion resistance of cold-worked 18 Cr, 8 Ni steel has been advantageously utilized for some time, particularly in aircraft and rail car structures. There are, however, certain limitations on the use of such materials because the high strengths can be obtained only by cold-working, limiting the available products to sheets, strip, wire and tubes. The authors sought to overcome these limitations by resorting to precipitation-hardening, which has been used so successfully in nonferrous metallurgy but only to a limited extent in iron-base alloys. Accomplishment of this objective not only overcame the limitations, but also effected certain improvements in mechanical and other properties. This paper is an account of the development by Carnegie-Illinois Steel Corporation of a precipitation-hardening 18-8 stainless steel (called Stainless W‡ and tentatively identified as type 322). A description is given of its composition and metallurgical characteristics, heat-treatment, physical and mechanical properties and corrosion resistance. Development of the New Steel For a considerable length of time the authors were unable to determine the mechanism of the precipitation-hardening process that had been noted by Ffield18,19 in 18-8 Ti or 18-8 Cb after cold-working and reheating to moderately elevated temperatures. All known variables were exhaustively studied, but with little success. However, results began to indicate that chemical composition was the most important variable, particularly the ratio of austenite-forming to ferrite-forming elements. The investigators then focused their attention upon the composition, and, in particular, upon the element titanium and its mode of alloying in the presence of other elements. A heat was obtained that could not be brought to the softness level of annealed 18-8. The response to cold-straining and aging* was very marked by previous standards, and, more important, cold-straining was found to be entirely unnecessary to produce the precipitation-hardening effect. The chemical composition of this heat was: C, 0.06 per cent; Mn, 0.54; P, 0.016; S, 0.016; Si, 0.58; Ni, 7.28; Cr, 17.60; Ti, 0.90; Al, 0.17. For some time the development work, particularly on composition, was carried

Jan 1, 1947

By Gorr W. W., R. Smith, Wyche E. H

The combination of high strength and corrosion resistance of cold-worked 18 Cr, 8 Ni steel has been advantageously utilized for some time, particularly in aircraft and rail car structures. There are, however, certain limitations on the use of such materials because the high strengths can be obtained only by cold-working, limiting the available products to sheets, strip, wire and tubes. The authors sought to overcome these limitations by resorting to precipitation-hardening, which has been used so successfully in nonferrous metallurgy but only to a limited extent in iron-base alloys. Accomplishment of this objective not only overcame the limitations, but also effected certain improvements in mechanical and other properties. This paper is an account of the development by Carnegie-Illinois Steel Corporation of a precipitation-hardening 18-8 stainless steel (called Stainless W‡ and tentatively identified as type 322). A description is given of its composition and metallurgical characteristics, heat-treatment, physical and mechanical properties and corrosion resistance. Development of the New Steel For a considerable length of time the authors were unable to determine the mechanism of the precipitation-hardening process that had been noted by Ffield18,19 in 18-8 Ti or 18-8 Cb after cold-working and reheating to moderately elevated temperatures. All known variables were exhaustively studied, but with little success. However, results began to indicate that chemical composition was the most important variable, particularly the ratio of austenite-forming to ferrite-forming elements. The investigators then focused their attention upon the composition, and, in particular, upon the element titanium and its mode of alloying in the presence of other elements. A heat was obtained that could not be brought to the softness level of annealed 18-8. The response to cold-straining and aging* was very marked by previous standards, and, more important, cold-straining was found to be entirely unnecessary to produce the precipitation-hardening effect. The chemical composition of this heat was: C, 0.06 per cent; Mn, 0.54; P, 0.016; S, 0.016; Si, 0.58; Ni, 7.28; Cr, 17.60; Ti, 0.90; Al, 0.17. For some time the development work, particularly on composition, was carried

Jan 1, 1947

By W. S. CAYPLESS, H. O. Hofman, E. E. HARRINGTON

I. INTRODUCTION. LIME-ROASTING is a term proposed by Ingalls 1 for the operation of forcing air under pressure through a mixture of galena and lime at the kindling-temperature with the object of oxidizing lead and sulphur and of fritting or fusing the charge. If, finely-divided galena were treated in this manner without the addition of lime, the heat set free by the oxidation of part of the lead and the sulphur would be sufficiently great to fuse undecomposed sulphide, and thus stop desulphurization. Besides the chemical action that the addition of lime, limestone or gypsum to the charge may have, the admixture has the physical effect that it keeps the particles of galena separated from one another and accessible to the oxidizing effect of the air. At present, three methods of lime-roasting are carried out on a working-scale, the Huntington-Heberlein, the Carmichael-Bradford and the Savelsberg2 processes. In the last, which interests us here, an 8-ton charge is made up of galena, limestone and perhaps some siliceous or ferruginous flux; the whole is crushed to pass a screen with 3-mm. holes and moistened with 5 per cent of water. It is fed gradually into a bowl-shaped converter, 6.56 ft. in diameter, supported by trunnions attached to a truck. On the .bottom the converter has a grate with blast-inlet beneath. In starting, the truck with the converter

Jan 1, 1907

By G. P. Gladis, R. H. Atkinson

PALLADIUM has been used for jewelry for many years, particularly in conjunction with gold. This use increased in amount during the war, as palladium and gold were only moderately used for war purposes while demands for platinum and some of the other members of the platinum group were so great that their use in jewelry was prohibited. Palladium hardened with a small percentage of ruthenium has the necessary technical properties and appearance for good jewelry, and it is sufficiently rare to be desirable for luxury items-at least 100 times as rare as gold. Although both visual and spectrophotometric examination demonstrated that the color of palladium was almost the same as that of platinum, a few jewelers found the surface of palladium, even after some polishing, rather dark in areas that had been repeatedly heated during the soldering necessary to assemble certain types of handmade ornaments. This phenomenon is not to be confused with the thin, bluish oxide film that can be produced by heating in air over the range 400° to 800°C., as that film is easily reduced by dipping in warm 5 per cent formic acid or in warm methanol. It was suspected that the difficulty arose from heating in atmospheres that were alternately oxidizing and reducing, as Wise and Vines1 had found that this opened the grain boundaries of palladium and palladium-silver alloys in the same manner as in pure silver, as reported by Martin and Parker.2 This damage is caused by the reaction between oxygen in solid solution in the metal, acquired when heated under oxidizing conditions, and hydrogen diffusing in from subsequent heating under reducing conditions; the steam cannot diffuse out and therefore builds up sufficient pressure to disrupt the metal near the surface. Copper and various other metals can be damaged similarly, but platinum is nearly immune; therefore the problem was new to the platinum jeweler. Sulphur in the fuel gas also can cause trouble but did not appear to be dominant in the present instance. Metallographic examination of both pure palladium and ruthenium-palladium showed that the usual torch using oxygen and city gas as normally operated did in fact cause the surface and subsurface damage that had been observed, and also disclosed that a reducing flame caused more damage than an oxidizing flame and was very damaging even in the absence of any intentional swing in atmosphere from oxidizing to reducing (Fig. 7); besides the surface damage, there was serious loss of ductility. A full explanation of the mechanism of attack is not evident at the moment, but may be allied to the attack that occurs on heating catalytically active metals in nonequilibrium atmospheres.

Jan 1, 1946

CHUQUICAMATA, as the Chile Copper Company's mine is known, has the largest developed deposit of copper ore in the world. Indeed, it is improbable that its equal will ever be found. The Union Miniére du Haut Katanga, operating in the Belgian Congo, may some day surpass Chuquicamata in the total amount of copper produced; or one of the companies developing the rich copper region of Northern Rhodesia may ultimately outdo it. But in each instance, the ore will come from a group of mines separated by 80 miles or more; whereas the deposit at Chuquicamata is one vast integral mass containing as a minimum probably 1,000,000,000 tons of ore, averaging better than 8.5 per cent copper, and as a maximum-well, most any reasonable figure might err on the low side. Utah Copper approaches Chuquicamata more nearly than any other in tonnage of exploitable ore; but Utah's ore is less than half as rich. The figure for the aggregate copper content of the reasonably assured ore at Chuquicamata is breath-taking at 50,000,000,000 pounds. Other distinctions has Chuquicamata: It was the first of the Porphyry Coppers to use leaching as the method of treating the ore; its plant cost for producing is lower than that of any of the others, only Braden and Utah being close rivals; and it was worked for its copper long before any of the others. According to an authentic article published in Ingeniería Internacional (May, v 1982) the Incas smelted copper ores from Chuquicamata prior to 1536. Diego de ALnagro, to whom Charles V, King of Spain, generously allotted a one-fourth portion of South America lying south of Cuzco, the Inca metropolis, made an expedition into Chile in 1534. Better known to history, perhaps, is Pizarro, who was awarded the area immediately north, and who proceeded

Jan 1, 1933

By Louis E. Reber

Jan 1, 1922

By Ralph H. Sweetser

N Greenup and Carter counties, in the northeastern part of Kentucky, are the remains of many old charcoal furnaces built and operated during the period from 1818 to 1892. They were all included in what was called the Hanging Rock district. In the summer of 1930 I visited ten of these old blast furnaces, as follows:

Jan 1, 1931

By John L. Lamont, Walter Crafts

THE principle formulated by Grossmann1 for calculating hardenability of steel by multiplying the ideal diameter of "pure" iron-carbon alloys by factors for grain size and alloying elements has been confirmed on many steels and has proved useful in designing substitute alloy steels. Grossmann found that the typical behavior of the multiplying factors was to increase directly in proportion to the amount of the alloy present in a steel. However, the multiplying factor for the effect of silicon on hardenability was found by Grossmann to increase to a lesser degree as the amount of silicon was increased. In view of the in¬creasing use of silicon in heat-treating steels, the effect of silicon on hardenability is becoming more important. Calculation of the hardenability of high-silicon steels made at the Union Carbide and Carbon Research Laboratories, Inc., indicated that the multiplying factor for silicon increased directly in proportion to the amount of silicon present. A more extended study of high-silicon steels covering fairly wide ranges of grain size, carbon, manganese, and aluminum has confirmed that up to 2 per cent silicon the multiplying factor is directly proportional to the silicon content. Manganese and aluminum factors have also been determined. The results of the study offer strong confirmation of the general validity of Grossmann's multiplying principle. TESTING PROCEDURE Steels on which the study of the effect of silicon on hardenability was based were made in high-frequency induction furnaces using Armco iron and standard alloying materials. The ingots were forged to bars, and sections were normalized prior to machining Jominy hardenability test specimens. The Jominy test was carried out under standard conditions.2 The depth of hardness penetration for determination of ideal diameter at "half hardness" was taken at the hardness level indicated in Fig. 20 in Grossmann's paper by the solid line for 50 per cent martensite in plain carbon steel. The depth of penetration of hardness on the Jominy specimen was converted to ideal diameter by the relation given in Fig. 28 of Grossmann's paper. Chemical analysis was determined on a sample taken adjacent to the Jominy specimen. Aluminum was determined as "acid-soluble aluminum" rather than as total aluminum, as it is probably more representative of the aluminum that is effective as an alloying agent. In addition to the elements nominally present in the steels, analyses were made for residual phosphorus, sulphur, nickel, copper, molybdenum and chromium on one heat of those made with the same materials during the same period. Actual grain size was determined by microscopic examination of small samples quenched in water after receiving the same thermal cycle as the Jominy hardenability specimens. Chemical analyses, heat-treatment, grain size, and hardenability are shown in Table I representing three ranges of composition.

Jan 1, 1943

By C. B. Foster, S. I. Freedman, E. M. Jamgochian

Coal-oil mixture (COM) combustion technology is regarded by the US Department of Energy (DOE) as near term and Potentially applicable to existing utility and industrial steam generators and for injection into blast furnaces. From work done previously, it has been established that COM can be burned in existing boilers and blast furnaces. Therefore, the issues being addressed by the current DOE program are: (1) determination of best available technology to achieve environmentally acceptable long-term reliable operation and (2) determination of applications for which COM can be utilized economically. Some of the technological options have begun to be determined by projects already under way. However, many projects are still in the early stages of development.

Jan 1, 1980

By S. Warren Hobbs

The section of the Northwestern United States that includes the northern Rocky Mountains and adjacent areas to the west and east is one of large mineral production and important mineral potential. The metallic ore deposits vary widely in age and type and their geologic settings are similarly diverse. A brief resume of the region's physiographic characteristics and geology sets the framework for the selected ore districts that are described in following papers and makes it possible to place these ore deposits in their proper reference to space and time.

Jan 1, 1968

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,' 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