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By William E. Ford, Edward Salisbury Dana

274. The PHYSICAL CHARACTERS of minerals fall under the following heads : I. Characters depending upon Cohesion and Elasticity - viz., cleavage, fracture, tenacity, hardness, elasticity, etc. 11. Specijic Gravity, or the Density compared with that of water. 111. Characters depending upon Light - viz., color, luster, degree of trans- parency, special optical properties, etc. IV. Characters depending upon Heat -viz., heat-conductivity, change of form and of optical characters with change of temperature, fusibility, etc. V. Characters depending upon Electricity and Magnetism. VI. Characters depending upon the action of the senses-viz., taste, odor, feel.

Jan 1, 1922

JOSEPH W. RICHARDS, Chairman. J. E. JOHNSON, JR., Vice-Chairman. ARTHUR S. CALLEN, Secretary, 453 Chestnut St., So. Bethlehem, Pa. SUB-COMMITTEES IRON ORE DWIGHT E. WOODBRIDGE, Chairman. ERNEST F. BURCHARD, WILLIAM KELLY, CHARLES F. RAND, FELIX A. VOGEL. BLAST FURNACES II. A. BRASSERT, Chairman. WILLIAM H. BLAUVELT, AMBROSE N. DIEHL, JAMES GAYLEY RICHARD V. McKAY. STEEL WORKS HENRY D. HIBBARD, Chairman. GUILLIAEM AERTSEN, C. F. W. RYS, .1. S. UNGER. FRANK D. CARNEY, A. A. STEVENSON, WILLIAM It. WALKER. MECHANICAL TREATMENT CHARLES A. BUCK, Chairman. ROBERT W. HUNT, GEORGE MESTA, FREDERICK W. WOOD.

Jan 6, 1915

CHARLES KIRCHHOFF, Chairman. ALBERT SAUVEUR, Vice-Chair-man. A. A. STEVENSON, Vice-Chair-man. HERBERT M. BOYLSTON, Secretary, Abbot Bldg., Cambridge, Mass. John Birkinbine, J. Esrey Johnson, Jr., Felix A. Vogel, William H. Blauvelt, William Kelly, Leonard Waldo, James Gayley, Richard Moldenke, William R. Walker, Henry D. Hibbard, Joseph W. Richards, William R. Webster. Henry M. Howe, E. Gybbon Spilsbury, Frederick \V. Wood. Robert W. Hunt, A. A. Stevenson is appointed an additional Vice-Chairman of the Committee. He will serve as Acting Chairman during the absence abroad of Professor Sauveur.

Jan 7, 1913

ASHBEL WELCH, Lambertville, N. J.: Dr. Dudley has given the wear of steel rails under four different conditions. He arrives at the conclusion that the softer rails, or those that from their composition ought to be softer, wear better than the harder. But there is another condition which has an important bearing on the subject, and should not be overlooked,—the weight on a wheel. With the lighter weights of the past, the softer rails may have worn best; with the heavier weights of the future, the harder may wear best. Weights will probably be increased up to the capacity of steel to bear; then doubtless the harder steel will wear best. A leaden rail with ten pounds on a wheel might carry millions of tons, but with one hundred pounds on a wheel, it would be destfoyed by a few thousand tons. So in the days of iron rails, my experience was that the softer rails under light machinery stood better than some of the harder; but under heavy machinery the softer were muqh the most rapidly destroyed. It is doubtless the same with steel. The pounding motion of the wheels loosens or spreads the particles of a thin film of steel; the pull lengthwise on the rail de-

Jan 1, 1881

By R. Moldenke

The presence of nickel-chromium in pig iron made fro111 Cuban oles is so well known that the word "Mayari" is unconsciously associated with it. Since 1904, when exploration of the Mayari deposits of iron ore in northeastern Cuba was undertaken, there llas been increasing interest in these ores. Tlie Transactions contain numerous references to t1ieln.l This iron ore, which is shipped to the Tinited States in the nodulizecl state, has been thoroughly tested and found very valuable; the deposit covers over 25,000 acres and there is in sight over 500,000,000 tons of ore that, by systematic mining, runs practically constant in composition. With nickel and chromium present, also titanium in sufficient quantities to attract attention, as well as extremely low phosphorus and sulfur contents, the iron founder is naturally interested in the utilization of RInpari ore for pig iron for the better grades of finishrtl iron products. The present point of coilsn~iil)tion ol ILlapri ore is at Sparrow's Poi111, where hlayari pig iron of ally desiretl coml>osition is made. The composition of the dried ore is about as follows: Iron -29 per cent., silica 3 pc.r cent., nickel 1 per cciit., chroiniun~ 1.5 per cent., alumina 11 per cent., ant1 coinbined water 13 per cent. When nodulized, the iron runs up to nearly 56 per cent., the silic:~, :tlumi~i:i, nickel, and c~llromiurn are slightly highr than the arno~l~its just given. Practically all the, combined wntcr is driven off aild the iiodulizccl ore carries only a few- tenths per cent. of 1 C. M. Weld: Residual Rrolvn Iron Ores of Cuba. Tmns, (1909) 40, 299. C. K. Leitll nnd If'. J. Mcncl: Origin of Iron Ores of Central and Northeostr~n rlbn. Trans (1911) 42, 00. C. W. Hayes: May:~ri and Mos Iron-ore Deposits in Cuba. Idem, 109. J. E. Little: Maynri lron Mincs, as Developed by the Spanish-American Iron ('0. Idem, 152. J. F. Iie~np: M'ryari Iron-ore Dcposi(s. Trans. (1915) 61, 3. C. K. Leith 2nd N. J. Mead: Additional Data on Origin of Lateritic Iron 01cs or Eastern Cubn. Tmns. (1916) 63, 75.

Jan 1, 1923

By R. Moldenke

The presence of nickel-chromium in pig iron made fro111 Cuban oles is so well known that the word "Mayari" is unconsciously associated with it. Since 1904, when exploration of the Mayari deposits of iron ore in northeastern Cuba was undertaken, there llas been increasing interest in these ores. Tlie Transactions contain numerous references to t1ieln.l This iron ore, which is shipped to the Tinited States in the nodulizecl state, has been thoroughly tested and found very valuable; the deposit covers over 25,000 acres and there is in sight over 500,000,000 tons of ore that, by systematic mining, runs practically constant in composition. With nickel and chromium present, also titanium in sufficient quantities to attract attention, as well as extremely low phosphorus and sulfur contents, the iron founder is naturally interested in the utilization of RInpari ore for pig iron for the better grades of finishrtl iron products. The present point of coilsn~iil)tion ol ILlapri ore is at Sparrow's Poi111, where hlayari pig iron of ally desiretl coml>osition is made. The composition of the dried ore is about as follows: Iron -29 per cent., silica 3 pc.r cent., nickel 1 per cciit., chroiniun~ 1.5 per cent., alumina 11 per cent., ant1 coinbined water 13 per cent. When nodulized, the iron runs up to nearly 56 per cent., the silic:~, :tlumi~i:i, nickel, and c~llromiurn are slightly highr than the arno~l~its just given. Practically all the, combined wntcr is driven off aild the iiodulizccl ore carries only a few- tenths per cent. of 1 C. M. Weld: Residual Rrolvn Iron Ores of Cuba. Tmns, (1909) 40, 299. C. K. Leitll nnd If'. J. Mcncl: Origin of Iron Ores of Central and Northeostr~n rlbn. Trans (1911) 42, 00. C. W. Hayes: May:~ri and Mos Iron-ore Deposits in Cuba. Idem, 109. J. E. Little: Maynri lron Mincs, as Developed by the Spanish-American Iron ('0. Idem, 152. J. F. Iie~np: M'ryari Iron-ore Dcposi(s. Trans. (1915) 61, 3. C. K. Leith 2nd N. J. Mead: Additional Data on Origin of Lateritic Iron 01cs or Eastern Cubn. Tmns. (1916) 63, 75.

Jan 1, 1923

By W. C. Meyer

In an effort to conserve and extend oil resources, the use of powdered coal-in-oil mixtures (COM) as an alternate fuel in oil-fired boilers is receiving increasing attention. For the approach to be successful, some degree of stability of the suspension against settling is needed. The variety of means available to achieve stability of this nonaqueous slurry is reviewed along with some of the physical and chemical concepts which underlie each method.

Jan 1, 1983

By GORDON H. FISHER

During the year 1945, the drilling pace in West Texas increased above that in the year 1944, and represented the highest number of well completions since 2941. The 1680 new wells drilled 8,287,958 ft. of hole for a per well average of 4933 ft. This depth is approximately 30o. ft. deeper than the average for the year 1944. Although the deepest well drilled in West Texas (Phillips Petroleum Company's Ada Price No. 1, in Pecos County) was completed during the year. 1944 to a depth of 15,279 ft. and tested the Ellen-burger horizon, the producing depth record for West Texas was set during the year 1945 with the completion of Amerada Petroleum Corporation's Jones No. I-A, in the Jones Ranch field, Gaines County, which now is producing at 11,422 ft. from the Devonian formation.

Jan 1, 1946

By E. C. Truesdale, Gerald Edmunds

A few years ago H. M. Cyr, working in the Research Laboratories of The New Jersey Zinc Co., produced a few pounds of zinc1 of such purity that no other elements were detected in it by spectrographic analysis, using the facilities then available. This zinc contained less than one ten-thousandth of one per cent of metallic impurities.&apos; During the decade that followed upon the laboratory production of this "spectro-graphically pure" zinc, commercial developments brought about the production of large tonnages of zinc of purity exceeding 99.99 per cent, and today zinc of 99.999 per cent purity is produced and marketed as "chemically pure" zinc. Typical analyses of present supplies of high-purity zinc are given in Table 1. Table 1.—Typical Analyses Percentnge by Weight Sum of Zinc Fe, Ib1 Fe Cd 1A1 cd Special High Grade*.......... 0.007b 0.005b 0.005b none O.OIOb C.P. (chemically pure)......... < 0.0002 0.0005c 0.000052 S.P. (spectrographically pure).. <0.0002d <0.00005d a A.S.T.M. Standard Specification for Special High Grade Slab Zinc (A.S.T.M. Designation: B 637). b Maximum. &apos; Fe chemically determined. Pb and Cd are spectrographically determined. d Differences between composition of C.P. and S.P. zinc are discussed later in this paper. The availability of commercial tonnages of special high-grade zinc has been the basis for the development of the zinc-base die-casting alloy industry which, in the year 1936, consumed one-eighth of the zinc used in the United States for all purposes. This and the C.P. and S.P. grades have given impetus to scientific investigations into the properties of pure

Jan 1, 1939

By E. C. Truesdale, Gerald Edmunds

A few years ago H. M. Cyr, working in the Research Laboratories of The New Jersey Zinc Co., produced a few pounds of zinc1 of such purity that no other elements were detected in it by spectrographic analysis, using the facilities then available. This zinc contained less than one ten-thousandth of one per cent of metallic impurities.&apos; During the decade that followed upon the laboratory production of this "spectro-graphically pure" zinc, commercial developments brought about the production of large tonnages of zinc of purity exceeding 99.99 per cent, and today zinc of 99.999 per cent purity is produced and marketed as "chemically pure" zinc. Typical analyses of present supplies of high-purity zinc are given in Table 1. Table 1.—Typical Analyses Percentnge by Weight Sum of Zinc Fe, Ib1 Fe Cd 1A1 cd Special High Grade*.......... 0.007b 0.005b 0.005b none O.OIOb C.P. (chemically pure)......... < 0.0002 0.0005c 0.000052 S.P. (spectrographically pure).. <0.0002d <0.00005d a A.S.T.M. Standard Specification for Special High Grade Slab Zinc (A.S.T.M. Designation: B 637). b Maximum. &apos; Fe chemically determined. Pb and Cd are spectrographically determined. d Differences between composition of C.P. and S.P. zinc are discussed later in this paper. The availability of commercial tonnages of special high-grade zinc has been the basis for the development of the zinc-base die-casting alloy industry which, in the year 1936, consumed one-eighth of the zinc used in the United States for all purposes. This and the C.P. and S.P. grades have given impetus to scientific investigations into the properties of pure

Jan 1, 1939

By AIME AIME

TEXAS not only produces millions of barrels of petroleum daily, but supplies the oil industry with an asset infinitely more valuable than liquld gold. That asset is leadership. The oil industry was built from its humble beginning a few decades ago into a potent force in world economy by human hands and human brains. One of these great leaders in the busy world of oil is Wallace Pratt, of the Humble company, who has been called to a position as director and member of the executive committee of the Standard Oil of New Jersey. So reads the Houston Post of June 3, 1937.

Jan 1, 1944

By AIME AIME

IN times of stress nations pick strong men to lead them. Similarly the Coal Division selected forceful Larry A. Shipman, fuel engineer for the Southern Coal and Coke Co., Knoxville, Tenn.. to lead it through the year 1945. He was born in Indianapolis May 13, 1891. Following graduation from a technical high school in that city Larry began his fuel career approximately 35 years ago attached to one end of a scoop shovel, firing locomotives for the Pennsylvania Railroad. At the end of two years he transferred to the New York Central Lines and held these jobs successively: locomotive fireman, engineer, fireman instructor, supervisor of instructors, and fuel engineer.

Jan 1, 1945

By William T. Folwell

The Lucky Friday mine east of Mullan, Idaho, is an outstanding example of a property in the Coeur d’Alene district where a small and insignificant- appearing silver-lead-zinc vein at the surface has changed at depth into a large vein of great importance. The Lucky Friday vein has little if any surface expression and above the 1200 level the ore shoots are small and discontinuous. Between the 1200 level and 2450 level, the lowest developed level, the main ore shoot has shown remarkable improvement on each succeeding lower level, and today the mine is one of the major lead-silver producers in the Coeur d&apos;Alene district. History: The Lucky Friday property is on the north side of the South Fork of the Coeur d&apos;Alene River in sections 25, 26 and 35, T. 48 N., R. 5 E., Hunter mining district, Shoshone County, Idaho. This is about one mile east of the town of Mullan, which serves the eastern portion of the Coeur d&apos;Alene district. The southern part of the property is crossed by a branch line of the Northern Pacific Ry. and by U. S. Highway 10. This highway is the principal road crossing the panhandle of Idaho and connects the district with Spokane, Wash., on the west and Missoula, Mont., on the east. The main portal and surface plant of the Lucky Friday mine is at an elevation of 3365 ft, only a short distance above the valley floor and a few hundred feet from U. S. Highway 10, so the mine is readily accessible for year-round operation.

Jan 12, 1958

By H. H. Rachford

Numerical solutions of immiscible flow problems in which dispersive effects of capillarity are dominated by convection require excessively fine grid spacing with attendant high computing costs. The use of coarser spacing reduces cost but often produces oscillation or undue dispersion associated with displacement fronts, A numerical formulation is proposed here which should be applicable to two-dimensional flow problems. it is in part analogous to an approach previously tested for miscible systems. The convective transport is approximated using a change of variables to yield a coordinate system moving approximately with the local characteristic velocity. The capillarity-induced dispersive terms in the differential system describing the process are approximated with respect to a fixed coordinate system by the usual implicit formulation. One-dimensional tests of the procedure yielded results in which the saturation profiles tended smoothly to the zero-capillary pressure solution as the ratio of viscous to capillary forces was successively increased in a sequence of calculations. This contrasted favorably with solutions by other numerical procedures which would require attendant grid refinements to approach the zero capillary pressure results. INTRODUCTION Numerical solution of displacement problems has until recently relied on applying methods developed primarily for transient heat-flow problems. Such problems are classified as parabolic in type, and where the heat transport is purely by diffusion their solutions are characterized by a high degree of smoothness. It is not surprising, therefore, that for approximating these solutions available finite difference methods are quite adequate. In flow problems the transport is partly by diffusion, partly by convection or flow. Although the problem remains of parabolic type because the dispersive effects of capillary forces or diffusion play some role in every displacement, at high flow rates the problem is dominated by convection, and solutions tend toward those of equations of the hyperbolic type. Solutions of hyperbolic problems are characterized by the translation of fronts, or discontinuities, that may progressively increase in sharpness. Numerical methods for treating parabolic problems become less and less satisfactory as displacement rates increase and the role of dispersion due to concentration or capillary pressure gradients becomes small relative to transport due to flow. In computation the difficulty manifests itself as an error associated with the grid size chosen. 1-6 In summary, if the heat-flow type approximations are to include the terms arising due to convection, one of several choices may be made: (1) an upstream (to the direction of flow) approximation for the convection terms may be used; (2) a centered-in-distance (CID) approximation may be used; or (3) a recently developed approximation based on the theory of oscillation matrices may be chosen.6 The last appears to have significant promise for one-dimensional flow problems; its extendibility to two or three dimensions is an open question. In either of the first two approaches, a suitably small ratio of v&/D must be maintained, where v is the velocity, & is the grid spacing and D the effective dispersivity in the direction of flow. In the first choice, the approximation of the convective part is only first-order correct and errors introduced appear as a numerically induced dispersivity of magnitude proportional to v?x. In the CID choice, the approximation can be second-order correct, but the difference formulation fails to satisfy the maximum principle unless a condition on v?x/D is met. Practically, this means that for high flow rates oscillatory solutions may result in the neighborhood of a front unless exceedingly small grid intervals are taken. While the procedure proposed by Stone and Brian4 permits a less severe limitation to be placed on this ratio, ultimately the flow rates increase relative to the dispersivity the oscillation obtains. Further, extensions of their approach to higher dimensional systems may be attended by considerable

Jan 1, 1967

By O. F. Thornton, D. L. Marshall

Results of the determination of the inter stitial water content of several core samples from oil reservoirs are presented. Data obtained by the capillary pressure method, which has recently been developed, are compared with water saturations measured in cores cut with oil-base mud and with values calculated from the electrical resistivity of the formation. The agreement between the capillary pressure and other methods, combined with the fact that similar agreement has been obtained by others, indicates that the capillary method properly applied yields results sufficiently accurate for most engineering purposes. In some cases, it may be possible to extend the utility of data obtained with the capillary pressure method by correlation of interstitial water saturation with more easily measured physical properties of the media. Introduction Several methods are in use for determining or for estimating the interstitial water saturation at given points within oil and gas reservoirs. The direct measurement of the water content of cores obtained with nonaqueous fluid in the hole is believed to be an accurate method under most conditions. The water saturation may be calculated by use of the resistivity curves of the electric log,&apos; although this method is not applicable under conditions that exist in some reservoirs. Recently, a method has been developed and described3.&apos; wherein the interstitial water saturation of cores is measured at a capillary pressure such that conditions existing in the reservoir are simulated. The purpose of this paper is to present data obtained by use of this latter method, and to compare the results obtained with determinations made by other means. Method The theory underlying the capillary pressure method applied to petroleum reservoirs has been discussed adequately in the literature by Garrison,2 Leverett,5 and Others.3,6,7 Briefly, and simply, capillary pressure is defined as the difference in pressure between two contacting fluid phases, such as oil and water. For the simplified sand, water and oil system illustrated in Fig I, the pressure difference can be stated as follows:6 where Pc is the capillary pressure in pounds per square inch, ? is the interfacial tension between oil and water in pounds per inch, r1 and r2 are the radii of curvature of the interface between oil and water in inches. Capillary pressure varies in a given reservoir with depth because of the greater density of the water phase as compared with oil or gas. The following equation expresses the difference in pressure between two points: p1- p2 - h?p/144 [2] where p1 — p2 is the capillary pressure difference in pounds per square inch, h is

Jan 1, 1947

By D. L. Marshall, O. F. Thornton

Results of the determination of the inter stitial water content of several core samples from oil reservoirs are presented. Data obtained by the capillary pressure method, which has recently been developed, are compared with water saturations measured in cores cut with oil-base mud and with values calculated from the electrical resistivity of the formation. The agreement between the capillary pressure and other methods, combined with the fact that similar agreement has been obtained by others, indicates that the capillary method properly applied yields results sufficiently accurate for most engineering purposes. In some cases, it may be possible to extend the utility of data obtained with the capillary pressure method by correlation of interstitial water saturation with more easily measured physical properties of the media. Introduction Several methods are in use for determining or for estimating the interstitial water saturation at given points within oil and gas reservoirs. The direct measurement of the water content of cores obtained with nonaqueous fluid in the hole is believed to be an accurate method under most conditions. The water saturation may be calculated by use of the resistivity curves of the electric log,&apos; although this method is not applicable under conditions that exist in some reservoirs. Recently, a method has been developed and described3.&apos; wherein the interstitial water saturation of cores is measured at a capillary pressure such that conditions existing in the reservoir are simulated. The purpose of this paper is to present data obtained by use of this latter method, and to compare the results obtained with determinations made by other means. Method The theory underlying the capillary pressure method applied to petroleum reservoirs has been discussed adequately in the literature by Garrison,2 Leverett,5 and Others.3,6,7 Briefly, and simply, capillary pressure is defined as the difference in pressure between two contacting fluid phases, such as oil and water. For the simplified sand, water and oil system illustrated in Fig I, the pressure difference can be stated as follows:6 where Pc is the capillary pressure in pounds per square inch, ? is the interfacial tension between oil and water in pounds per inch, r1 and r2 are the radii of curvature of the interface between oil and water in inches. Capillary pressure varies in a given reservoir with depth because of the greater density of the water phase as compared with oil or gas. The following equation expresses the difference in pressure between two points: p1- p2 - h?p/144 [2] where p1 — p2 is the capillary pressure difference in pounds per square inch, h is

Jan 1, 1947

By Harrison Everett Ashley

(Pittsburg Meeting, March, 1910.) Slimes are usually defined as all material passing a certain-sized sieve, which is invariably the finest sieve employed by each metallurgist in his tests; 100-mesh and 200-mesh have been taken as the limits by different writers in recent volumes of the Transactions ; 150-mesh is common practice. The reader of the first two volumes of Richards 1 is impressed by the inflexibility with which all grinding-arrangements are praised or condemned according as they make little or much slime. Until recently, one of the principal aims of the mill-man was to keep down the slimes. He was obliged to have separate apparatus for sand- and slime-treatment. The latter was sometimes puzzling and erratic. Often it was found most .economical to omit treatment of the slimes entirely, or to store them in immense basins or heaps, waiting for possible future improvements in methods of treatment. Recently, improved processes of agitation and filtration have made possible the successful extraction of values from many slimes. The tendency, when the metal is exceedingly finely disseminated, is to cut out all sand-treatment and to slime everything. These processes have been almost entirely mechanical in their conception, and it is the object of the present paper to show that certain chemical considerations may greatly hinder or assist their successful operation. It has long been a source of dissatisfaction to chemists that their analyses fail to be of much help to the clay-worker; that it is a matter of common occurrence for clays of closely identical ultimate chemical constitution to show the widest possible divergence in physical properties. * Published by permission of the Director of the U. S. Geological Survey. Ore Dressing (1903).

Aug 1, 1910

By Ashbel Welch

Ashbel Welch, Lambertville, N. J.: Dr. Dudley has given the wear of steel rails under four different conditions. He arrives at the conclusion that the softer rails, or those that from their composition ought to be softer, wear better than the harder. But there is another condition which has an important bearing on the subject, and should not be overlooked,—the weight on a wheel. With the lighter weights of the past, the softer rails may have worn best; with the heavier weights of the future, the harder may wear best. Weights will probably be increased up to the capacity of steel to bear; then doubtless the harder steel will wear best. A leaden rail with ten pounds on a wheel might carry millions of tons, but with one hundred pounds on a wheel, it would be destfoyed by a few thousand tons. So in the days of iron rails, my experience was that the softer rails under light machinery stood better than some of the harder; but under heavy machinery the softer were much the most rapidly destroyed. It is doubtless the same with steel. The pounding motion of the wheels loosens or spreads the particles of a thin film of steel; the pull lengthwise on the rail de-

Jan 1, 1881

By M. A. Grossman

The harden ability of most steels can be predicted within 10 to I5 per cent provided the complete chemical composition is known, including "incidental" elements; and provided the as-quenched grain size is known; and provided, finally, that the composition and heating temperatures for hardening are such as to result in austenite free from carbide particles. In the method proposed herein, the steel is considered as having a base hardenability due to its carbon content alone (the hardenability of a "pure steel" of the given carbon content, without any other elements), and this base hardenability is multiplied by a multiplying factor for each chemical element present. After multiplying all these together, the final product is the hardenability. Grain size may be taken into account either in the base hardenability or after the multiplication. Hardenability is stated in terms of "ideal critical diameter", namely, the diameter of bar, in inches, that will just harden all the way through (absence of un-hardened core) in an "ideal" quench, and the calculation may also be related to the Jominy test The data bring out certain features rather clearly. For example: i. It is quite useless to attempt to predict hardenability unless all elements, including "incidentals,,) are known; thus an "incidental,, chromium content of 0.20 per cent increases the hardenability by about 50 per cent. 2. The relative effectiveness of different alloys is sometimes unexpected; thus molybdenum when calculated in this way appears to be of the same order of effectiveness as manganese, rather than much more powerful, as would appear to be common experience; observe that an increase from no manaanese to 0.20 per cent Mn provides a multiplying factor of 1.67, and an increase from no molybdenum to 0.20 per cent Mo provides a factor of 1.63, an increase of over 60 per cent in each case. However, if to a steel containing 0.50 per cent Mn there is added "20 points of manganese," the factor is raised from 2.65 (for 0.50 per cent Mn) to 3.35 (for 0.70 per cent Mn), or an increase of only 26 per cent. Thus the fist small addition of an element has a much more powerful percentage effect than an equal further addition when some is already present, and in most cases the effect of molybdenum is considered in relation to a steel in which molybdenum is absent. 3. If two elements are equally effective, a greater hardenability will be obtained by using, for example, 0.5 per cent of each than by using I.o per cent of either of them alone. 4. A knowledge of the as-quenched grain size is essential for precise work, since a difference of only one grain size number (say No. 7 instead of No. 6) makes a difference of almost 10 per cent in hardenability (in these units); this, however, does not apply to certain It should be emphasized that in chromium steels (over 0.30 per cent Cr) and chrome-molybdenum and chrome-vanadium steels, un-dissolved carbides are likely to be present in the steel as quenched, and that in such cases the charts can indicate only a maximum Passible hardenability, whereas the extent of hardening actually obtained may be much less. Thus tests on a number of chrome-molybdenum steels have indicated a degree of hardening amounting to only 50 to 65 per cent of the maximum possible, and in chromium steels from full hardening (100 per cent) down to as low as 70 per cent. On the other hand, when the amount of such elements is small (Cr under 0.30 per cent, Mo up to 0.25 per cent in the

Jan 1, 1942

By M. A. Grossman

The harden ability of most steels can be predicted within 10 to I5 per cent provided the complete chemical composition is known, including "incidental" elements; and provided the as-quenched grain size is known; and provided, finally, that the composition and heating temperatures for hardening are such as to result in austenite free from carbide particles. In the method proposed herein, the steel is considered as having a base hardenability due to its carbon content alone (the hardenability of a "pure steel" of the given carbon content, without any other elements), and this base hardenability is multiplied by a multiplying factor for each chemical element present. After multiplying all these together, the final product is the hardenability. Grain size may be taken into account either in the base hardenability or after the multiplication. Hardenability is stated in terms of "ideal critical diameter", namely, the diameter of bar, in inches, that will just harden all the way through (absence of un-hardened core) in an "ideal" quench, and the calculation may also be related to the Jominy test The data bring out certain features rather clearly. For example: i. It is quite useless to attempt to predict hardenability unless all elements, including "incidentals,,) are known; thus an "incidental,, chromium content of 0.20 per cent increases the hardenability by about 50 per cent. 2. The relative effectiveness of different alloys is sometimes unexpected; thus molybdenum when calculated in this way appears to be of the same order of effectiveness as manganese, rather than much more powerful, as would appear to be common experience; observe that an increase from no manaanese to 0.20 per cent Mn provides a multiplying factor of 1.67, and an increase from no molybdenum to 0.20 per cent Mo provides a factor of 1.63, an increase of over 60 per cent in each case. However, if to a steel containing 0.50 per cent Mn there is added "20 points of manganese," the factor is raised from 2.65 (for 0.50 per cent Mn) to 3.35 (for 0.70 per cent Mn), or an increase of only 26 per cent. Thus the fist small addition of an element has a much more powerful percentage effect than an equal further addition when some is already present, and in most cases the effect of molybdenum is considered in relation to a steel in which molybdenum is absent. 3. If two elements are equally effective, a greater hardenability will be obtained by using, for example, 0.5 per cent of each than by using I.o per cent of either of them alone. 4. A knowledge of the as-quenched grain size is essential for precise work, since a difference of only one grain size number (say No. 7 instead of No. 6) makes a difference of almost 10 per cent in hardenability (in these units); this, however, does not apply to certain It should be emphasized that in chromium steels (over 0.30 per cent Cr) and chrome-molybdenum and chrome-vanadium steels, un-dissolved carbides are likely to be present in the steel as quenched, and that in such cases the charts can indicate only a maximum Passible hardenability, whereas the extent of hardening actually obtained may be much less. Thus tests on a number of chrome-molybdenum steels have indicated a degree of hardening amounting to only 50 to 65 per cent of the maximum possible, and in chromium steels from full hardening (100 per cent) down to as low as 70 per cent. On the other hand, when the amount of such elements is small (Cr under 0.30 per cent, Mo up to 0.25 per cent in the

Jan 1, 1942