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By Donald Gilbert

PRIOR to July, 1919, the sampler at each mine of the Anaconda Copper Mining Co. in Butte did his work in his own way and was responsible to the mine foreman only. At that time, the sampling at all the company's Butte mines was placed in charge of a member of the geological department and stand-ardized methods of doing the work, were adopted. These standards were incorporated in a set of instruc-tions accompanied by blueprints representing typical conditions. The main features of the instructions were as follows: All samples to be cut at breast height and horizontally, regardless of dip of vein, and the horizontal width reported. A single sample to include not more than a 5-ft. width of the breast and to weigh not less than 4 lb. for this width. Where the vein is made up of two or more streaks of different hardness or mineral content, each streak is to be sampled sepa-rately and the average value of the combined width figured. If two streaks of ore are separated by a streak of waste, which is not sampled, in obtaining the average value of the breast the waste must be figured in with a zero assay. Drifts to be sampled in the breast after each round. Raises to be sampled for each floor raised. Each end to be sampled separately and the average width and value of the two ends to be used as the average of the floor. All veins cross-cut to be sampled along the side of the cross-cut, at breast height and horizontally. Where the vein strikes at an acute angle to the line of the cross-cut, the width of sample must be corrected to show the horizontal width at right angles to the line of strike of the vein. Rill stopes must be sampled across the full mining width. In square-set stopes, each set must be sampled separately along the line of the caps. Waste portions of the vein which are mined for filling must not be included in the sample.

Jan 2, 1922

By L. O. Bond, R. P. Alger, A. W. Schmidt

Well logging provides valuable information for planning coal mining operations. In addition to locating, defining, and evaluating coal beds, electrical logs indicate the relative competence of roof and floor formations. Electrical well logging is the .recording of various physical, chemical, or physicochemical properties of the strata penetrated by a drill hole. To perform logging operations, borehole measuring probes, or sondes, are lowered on a cable into the drill hole. Insulated conductors in the cable pass power to the sonde and transmit signals to the surface. As the sonde is pulled up the hole, the measurements are recorded as a well log. These measurements serve to define the formation lithology. Common rock minerals exhibit characteristic log values such that computer analysis of the log data defines the mineral content of the formations. Shales, carbonates and sandstones, and coal beds are readily distinguished. Furthermore, preliminary results in coal studies indicate the log data delineates variations in ash and moisture contents. Of major concern in planning mining operations is knowledge of roof and floor competence. Here again the logs provide valuable information. Measurements of formation density and acoustic wave velocity provide data for computation of a compressional modulus. This compressional modulus is an effective index of formation competence. Electrical logging thus efficiently provides information for economic planning of mining operations.

Jan 1, 1972

By Walter Miller

Any review of the engineering progress made in 1932 in the petroleum refining industry must necessarily be broad and general, improvements having been made in practically all major branches of this activity. Several factors contributed to an advancement on a wide front, much of it coming from those active in refining, considerable from those not, immediately in it but engaged in designing and installing equipment and maintaining large and capable staffs of experts in both engineering and development work. Another factor has been the ability of the refiner, because of less than capacity operation, to carry on experimental and development work in regular plant equipment. The movement to higher antiknock value gasoline has continued through 1932, and the average improvement of the more widely sold branded gasolines is from 3 to 4 points higher in the octane scale. A very great improvement was brought about during the year in the method of determining the octane number of gasoline. While the procedure and equipment for determining this value as developed by the Cooperative Fuel &search Steering Committee prior to 1932 had received fairly general acceptance, evidence that it did not always evaluate in a measure consistent with road performance quickly accumulated, and led to further effort to synchronize laboratory results with actual use. As the result of some really brilliant work on the part of the C.F.R. Committee and a large number of collaborators, it was found that a comparatively minor modification of the previously developed equipment and method gave surprisingly concordant results between laboratory tests and trial per-formance on the road. This method has been officially accepted by the Society of Automotive Engineers and the American Petroleum Institute, and will according to present plans go into general use on April 1, 1933. The American Society for Testing Materials has studied the method but at the time of writing this had not reached a final decision regarding it. Improved Volatility of Gasoline The most notable trend during the year, in addition to a very considerable increase in antiknock value referred to above, has been in the

Jan 1, 1933

By Donald C. Moore

INTRODUCTION Published laboratory procedures used by the major crusher manufacturers for estimating crusher size are based upon techniques developed in the mid 1940's. Specifically, the two largest U.S. crusher manufacturers are using the Bond impact procedure. Although the procedure is still in use, there is little confidence in the results. Unless the laboratory results fall within a preconceived range, personal experience is used for selecting the number of crushers and connected horsepower (Coleman, 1978). There have been numerous theoretical studies of the communition of particles. However, no procedure has been widely acclaimed for predicting crusher power requirements. Experimental studies have included breakage by slow compression, slow speed impact and high speed impact. Theoretical results have increased our knowledge of the comminution process, but the procedures have not been capable of analyzing the complex mechanism of industrial crushing machines. The purpose of this chapter is to review the empirical crushing procedures that have been used, including advantages and disadvantages. A new procedure which has been in development at Allis-Chalmers Corp. from 1977 to 1982 is detailed. Actual results of the new procedure on a concentrator feasibility study are included. EXPERIMENTAL GOALS The goals of a laboratory crushability procedure are accurate predictions of: (1) Rock crushability, measured as energy per unit mass. (2) Crusher product size analysis. A procedure capable of predicting these parameters should be inexpensive and require a minimum amount of sample. CRUSHABILITY TESTS Bond Impact Procedure F. C. Bond (1946) detailed the development of the pendulum impact device that is still used by the leading crusher manufacturers (Bond; Rexnord, 1976). The device (Fig. 1) is comprised of two bicycle wheels with 13.6 kg steel hammers tangentially attached to the rims. The hammer faces are 50 mm apart at rest. On opposite ends of the hammers lifting

Jan 1, 1982

By Rufus J. Foster

During the discussion on the Preparation and Utilization of Sniall Sizes of Anthracite (page 613 of present volume), several inquiries were made concerning the use of the McClave grate, which was mentioned by Mr. Coxe as having proved satisfactory in the generation of steam at his collieries, and also at a large number of industrial estal)lishments in Scranton and elsewhere. For a more satisfactory repIy to such inquiries than could be furnished in the oral discussion, I have prepared the following paper to be included in the published proceedings. And, as the use of the fuel under consideration necessarily requires the employment of a blower to change the fire, from a condition giving an incandescent radiant heat only to one giving a hot gaseoua flame as well, I shall add a description of the McClave Argand blower and its method of action. The grate and blower combined form a complete and effective system fcr burning small fuels, such as anthracite culm, birdseye, buckwheat, bituminous slack, etc., in boiler and other furnaces; while the grate alone is now extensively used with the larger sizes of hard and soft coal in furnaces where blast is riot required. Fig. 1 is a view of the RlcClave grate as built in two sections. It is constructed on the principle best approved by practice to prevent warping and burning out; that is, it presents no long lines of

Jan 1, 1892

By R. J. Murphy, N. J. Grant, J. W. Dowding

A large number of blast furnace slag-metal tests were examined to determine if the manganese reduction could be used as a primary indicator of the degree of oxidation or reduction of the slag and of its desulphurizing power. Slag basicity and temperature were also evaluated. Two laboratory heats were made and sampled prior to reaching equilibrium to check blast furnace data. IN a recent investigation of the factors affecting desulphurization in the blast furnace, is was evident that manganese reduction appeared to parallel the course of desulphurization. Grant, Kalling, and Chipman1 pointed this out in a series of time studies utilizing closely controlled laboratory melts. Fig. 1 is a composite plot of sulphur removal and manganese reduction as a function of time under two slags of different basicity. Manganese reduction appears to approach equilibrium at approximately the same rate as does sulphur. It was also demonstrated that the addition of oxygen to the slag, as manganese oxide, caused a sharp reversal of sulphur from the slag to the metal.' It has been shown that "Excess CaO" was a primary factor in measuring the degree of desulphurization under ideal reducing conditions,1,2 the following reaction being representative of the process: CaO (slag) + S + C (solid) = CaS(slag) + CO (gas) It was also evident that a second reaction could drive the sulphur from the slag into the metal. A suggested reaction was' CaS (slag) + 0 = CaO (slag) + S Any change in the oxidizing power of the system would thus affect both the sulphur and the manganese without causing any change in the calculated basicity of the slag. "Excess CaO," "Excess Base," and other similar basicity values, under such oxidizing conditions, would therefore not be the best measure of desulphurizing power; instead, as was shown by and Chipman" he oxygen content of the slag at low oxygen levels would be the controlling factor. Unfortunately, the extent to which FeO is reduced in the blast furnace makes it difficult to utilize slag FeO as an accurate indicator of the degree of oxidation. By comparison, manganese reduction in the blast furnace proceeds more slowly and is generally only about 40 to 70 pct complete. manganese, which is present in significant amounts and is readily analyzed, offers an opportun-

Jan 1, 1954

By W. J. Shearer

A COMPARISON of statistics relating to coal min-ing in Great Britain and the United States leads one to suspect widely differing conditions and practice. A brief review of some of the conditions may enable American mining men to appreciate more fully the difficulties with which British engineers are faced, and to some extent explain why American, coal can be sold f.o.b. mine at the present time at about 50 to 60 per cent of the cost of British coal at the mine, and why British man-shift outputs fall far below American at present being less than 30 per cent. Bulman gives the average depth of 6-ft. seams. in Britain at 1350 ft., and of 2-ft. seams at 517 ft. George S. Rice states that 90 per cent of American coal 'is taken from less than 600 ft. Much English coal is taken below 2000 ft. and some below 3000 ft. The total influence of depth on cost is not always evident. Room work as known in America becomes less advisable with increasing depth, as pillars crush badly if left -for any length of time. A limited amount of bord and pillar work, taking very small amounts of coal in the first working, takes the place of room work, with rapid working of the pillars as soon as the panels are broken. Ventilation difficulties increase tremendously with depth and thinning coal. In America the chief use of air underground is to dilute gas. In Britain it serves a dual purpose, in many cases the amount of air cir-culated being far in excess of the quantity necessary to dilute gas to reasonable proportions. At great .depths rock temperatures exceed-95 deg. F., and great volumes of air are necessary for rock cooling. At these high temperatures humidity becomes an important factor. At present a great deal of research is under way to find methods of overcoming the troubles experienced with high temperature and humidity in deep mines.

Jan 8, 1928

By Henry M. Howe

If a bar of wrought iron or steel is suddenly cooled from a bright red-heat, the contraction which then occurs is considerably greater than the expansion previously caused by heating the bar, so that its final length is considerably less than its initial length. Mr. Thomas Wrightson has investigated this phenomenon,* and has shown that not only does this permanent contraction occur on sudden cooling, but, if the heating and cooling be repeated, say fifty times, a further permanent contraction occurs at each successive cooling. In Mr. Wrightson's opinion, this contraction cannot be explained on mechanical grounds, and he ascribes it to some molecular change caused by sudden cooling; but I think that we need not invoke mysterious molecular changes to explain this phenomenon, which appears to me to be due to very simple and purely mechanical action. Let us consider the cooling as divided into two periods, in the first of which the exterior or skin of the bar becomes almost completely cooled, and hence tends to contract almost to its initial dimensions, while the still hot arid plastic interior contracts but little; in the second period the already cool skin remains nearly constant in temperature, and hence tends to contract but little, while the interior cools from a comparatively high temperature to the ordinary temperature, and hence undergoes great contraction. The excess of the contraction of the skin over that of the interior during the first period tends to make the bar bulge in the middle of its length. This, as well as the decrease of density which occurs, Mr. Wrightson correctly explains. The interior of the bar just sufficed to fill the skin when both were in their initial condition, before being heated at all. At the end of the first period, the volume of the still hot interior is more than the now contracted skin can hold while maintaining its initial shape; and the effect is much the same as when we powerfully blom into a soft India-rubher Lag of the shape of the skin of the bar—it bulges, and tends to approach the spherical shape, in which the ratio of surface to

Jan 1, 1886

By V. R. Garfias, A. C. Fernandez

Despite artificial curtailment in all the fields of Mexico during 1937, owing to strikes and other disturbances, the production of crude petroleum aggregated approximately 46,738,000 bbl., showing a substantial increase of about 5,571,000 bbl. over the preceding year. Most of this increase occurred in the Poza Rica area, where, although only two wells were completed during the year, production increased from 14,162,000 bbl. in 1936 to 18,634,000 in 1937. While production in the South fields (Golden Lane) remained practically stationary, the output in the heavy-oil district of the Northern fields showed an increase of 1,930,000 bbl., because production had been considerably curtailed during 1936. Production in the Isthmus of Tehuantepec decreased about 596,000 bbl., owing to labor disturbances. Crude run to stills in local refineries increased from 34,000,000 bbl. in 1936 to 36,650,000 in 1937. Exports of crude and refined products were approximately 22,700,000 bbl., or 500,000 bbl. less than in 1936. Domestic consumption, excluding ships bunkers, reached a total of 20,000,000 bbl., which shows a small increase of 200,000 bbl. over the. previous year. Domestic demand for gasoline is estimated at 3,400,000 bbl. for the year, which represents an increase of 500,000 bbl. over 1936. In all, 60 wells were completed in Mexico during 1937, as compared to 70 in 1936 and 74 in 1935. In proven areas 52 completions resulted in 25 producers and 27 failures. In the Northeastern area near the United States border, five gas wells were drilled, all of which were producers; one of them, in Camargo, came in with a daily production of 20,000,000 cu. ft. of gas. One well, resulting in a failure, was drilled in Las Uvas, Coahuila, and three wells were completed in Quebrache, to the southeast of the heavy-oil district, resulting in two small producers and one failure. TWO more wells drilled in San SebastiBn, east of the Golden Lane, were failures. Fields Northern Fields (Heavy-oil District).—A total of 11 producers and 22 failures was completed in the proven areas of the Northern fields, as compared to 16 producers and 25 failures in 1936. In the Altamira

Jan 1, 1938

By Clarence Zener

Theoretical considerations by one of the authors have ledl to the prediction that the dynamic internal friction of annealed metals has a broad maximum at a certain grain size. This prediction they have verified2 for alpha brass. In the present paper the theory is extended to include the precise manner in which the internal friction varies with grain size on either side of the maximum. New experimental data are presented to test this extended theory. The physical basis for the type of internal friction that is being investigated lies in the interplay between stress and temperature. Just as local fluctuations in temperature give rise to local fluctuations in stress, so likewise fluctuations in stress give rise to fluctuations in temperature. But temperature gradients give rise to necessarily irreversible thermal currents, and hence to internal friction. The theory for this type of internal friction has been developed quantitatively,³ and has been experimentally verified,4,5 for the particularly simple case of the transverse thermal currents accompanying transverse vibrations. Of more fundamental importance are the intercrystalline thermal currents accompanying all types of vibration. The variation in stress across grain boundaries arises from the elastic anisotropy and at least partial random orientation of the individual crystallites. An exact quantitative treatment of the internal friction due to these thermal currents is of course out of the question. However, much information can be obtained from general arguments.1,6 Thus when the frequency of vibration f is low, or when the grain size d is small, adjacent grains remain nearly in thermal equilibrium, and vibration proceeds isothermally with little internal friction. Again, when the frequency is high, or the grain size large, the heat flow per cycle is small, the vibration proceeds adiabatically with little internal friction. The internal friction will become a maximum in the transition region. The degree of adiabatic-

Jan 1, 1940

By Thomas H. Leggett

In speaking of the mining and economic conditions prevailing at the present time on the Rand, it is not my intention to go into the details of the mining practice, since this has been already well described both in the Transactions' and elsewhere,2 but rather to take a more comprehensive view of the industry and its surroundings as a whole, marking its general development and the lines of its future progress. In a paper entitled Deep-Level Shafts on the Witwaters-rand, with Remarks on a Method of Working the Greatest Number of Deep-Level Mines with the Fewest Possible Shafts,' presented to this Institute in August, 1900, I drew attention to the great cost of sinking the very deep vertical shafts that were then being seriously proposed as necessary for the development of the deeper areas, pointing out the strong advisability of working this ground by means of inclines to be sunk from the existing shafts of from 3,000 to 4,000 ft. in vertical depth. In this paper it is stated (p. 975): '" In short, practice upon the Rand now tends towards fewer vertical shafts and more underground inclines, especially for the very deep mining about to be undertaken." In consequence, the 6,000-ft. vertical shafts, at one time so much discuesed, have never been started, and they do not now seem likely ever to be. The necessity of placing all deep shafts further apart in order to make them control and exhaust larger areas was also dwelt upon. This economy wae vitally necessary for both

Jan 1, 1909

By John Jermain Porter

THe value of any particular ore, coke, or limestone, for iron-making, depends upon its effect, first, upon the quality or value of the resultant product; and second, upon the cost of smelting. The factors under the first head are the percentages of phosphorus, manganese, and other elements, which remain in the pig-iron ; while those under the second head are the percentages of iron, carbon, or lime, the slag-forming constituents, which must be fluxed, and any other ingredients which give rise to variations in cost of fuel and flux. The first of these criteria of value is perhaps not capable of being reduced to a general formula embracing all cases, since it must vary to a great extent with market-fluctuations. For example, Bessemer pig is worth sometimes more and sometimes less than foundry-pig; and the premium paid for high manganese varies within wide limits. The second, or smelt-ing-value, however, can be expressed numerically with a fair degree of accuracy; and it is with this phase of valuation that the present paper is concerned. The utility of a means of comparing numerically the relative smeltiug-values of difierent ores, cokes, and limestones, is self-evident, although it may not have importance in Northern practice, where materials are largely standardized. On the other hand, there are, especially in the South, many furnace-managers who must use a great variety of materials of widely varying grade; and it is with special reference to this district, and in connection with the efficiency-methods which I have elsewhere proposed,' that the methods herein described were devised.

Jan 1, 1913

By D. W. Fuerstenau, J. H. Brown

The paper by Professors Sun and Mitchell illustrates the value of ultrasonics as a tool for the mineral engineer. In particular, it opens up a number of possibilities to those interested in the field of comminution. The provision of desliming technique, which is thorough as well as rapid, is a distinct contribution, but the data of the paper suggest applications beyond desliming, in that the same treatments may be useful for size determination purposes. Fig. 1 shows that a marked dependence exists between particle size and the height to which it can be elevated by ultrasonic vibrations. While the curves are only extended down to a size of about 100 u, the fact that they appear to be increasing in slope in this range suggests that the separation may be even more marked here. This, we feel, is very strong evidence that a nlethod for fine sizing could be developed to use ultrasonic waves as the separating force. Professors Sun and Mitchell indicate that floccula-ti~n will present no difficulty: "During the investigation it was found that ultrasonic waves were able to dislodge the adhering gangue particles from the min- era1 surfaces and to disintegrate the soft particles into fine sizes." Thus, it appears that the use of ultrasonic waves as the power behind a size separation process may eliminate the problem of flocculation encountered in most wet sizing techniques. It would be interesting to size a fine material under conditions in which particles are known to be flocculated and under conditions where they are known to be dispersed. Use of a sizing technique of this nature may solve several problems that have long persisted in the fine sizing field. The flocculation problem may be overcome; the continuous production of closely sized fractions may be possible with a device similar to the one described; and with photoelectric methods, rapid analyses in the subsieve sizes may be possible. In general, we suggest that this paper be followed by a study of the sizing applications of the apparatus described. We feel that such a study would not only be rewarding in providing a new sizing technique, but also that the present paper almost requires such work to complete the picture of particle motion in a field of ultrasonic waves.

Jan 1, 1958

By Alexandre Pourcel

The perusal of Mr. Willard P. Ward's " Notes on the Behavior of Manganese to Carbon," presented at the Washington meeting of the Institute in February, 1882, has suggested further reflections on the same general topic, and has led to the preparation of the present paper. The same observation that Mr. Ward has put on record in his "Notes" was also made by myself at about the same time (in August, 1875), and under almost the same conditions. From a blast-furnace that was very hot, as was the furnace mentioned by Mr. Ward, I obtained a pig-iron containing about fifteen per cent. of manganese, gray in color, and very tough. It could be pulverized, but could not be cut with the chisel. I analyzed this iron and found that it contained, as I had suspected,a large amount of silicon. From this fact I drew the conclusion that the silicon had deprived the manganese of its power of dissolving carbon, since the latter, instead of occurring in the pig in combillation, appeared as graphitic carbon. I thus saw reproduced on a large scale, and demonstrated in a visible way, the property that Colonel Caron, a French scientist, had discovered in silicon,—the property of obstructing the process of hardening in steels by keeping the carbon in the graphitic condition. An attentive study of the conditions under which the phenomenon observed by Mr. Ward takes place led me to go back to operations of synthesis, and to make as I wanted them pig-irons containing varying quantities of silicon, manganese, and carbon. An iron, thus prepared, was intended to serve me as a chemical reagent in the production of steels cast without blow-holes, such as my lamented friend, Mr. A. L. Holley, has introduced and made known to the United States. What I needed in order to make very soft steels, cast without blow-holes, was an iron which, when it was added to the bath of steel, introduced into the bath a sufficient amount of silicon and of

Jan 1, 1883

By Enrique Touceda

As IN the case of steel and the non-ferrous alloys in general, the use of the microscope in connection with the manufacture of malleable cast iron has proved of inestimable value to the industry. Had its use not been invoked, many facts either would not be known at all or, if suspected, would be confined to the realms of conjecture. No fairer statement could be made than that the start of real progress in the industry was coincident with the application of metallography to the product, though the full significance of this statement can hardly be appreciated except by those who not only are conversant with conditions as they existed at the time referred to, but are familiar with the character of works' practice at the present time. A few years ago, about the only test made to ascertain the physical properties of the product, t except in the case of certain plants, was the bending of a casting to destruction, not only with the object of discovering whether or not the metal was ductile, but for the purpose of inspecting the fracture. The characteristics of the fracture, if correctly interpreted, were known to be of value in locating the trouble in, castings that were inferior. In general, it was found that if a casting of medium or heavy section would bend through a wide angle before failure took place, the fracture in the majority of cases would have a black velvety appearance; while if it was held at different angles to the direction of the rays of light, it would show a change of color and an iridescent sheen. But an inferior air-furnace heat or anneal might yield castings which, if thin and consequently largely decarburized, could be bent double on themselves and still not possess the fracture described. If, on the other hand, a casting broke short, its fracture might have one of a great many different color and structural peculiarities. Depending on the cause of the trouble, such castings might have any of the fracture characteristics, of which the following is but a partial list.

Jan 2, 1920

By W. W. Colpitts

To me, as to many other students of railroad needs, the necessity for reducing the dead weight in railroad rolling stock, both passenger and freight, has been apparent for, many years. The problem of weight reduction of passenger cars is so entirely different from that of freight cars, is so much more to the fore at the present moment and would seem to be so much nearer solution, that I shall confine myself in these remarks to the former. On the surface of things there would appear to be no close association of thought between the decline in traffic on the railroads, which is largely responsible for their present deplorable financial condition, and new metal alloys. It sounds like a trick riddle a school boy might propound to his parents. But that there is a relationship between the two, and one that bids fair to be of great mutual benefit to the railroads and the makers of .high-strength metal alloys, I hope I shall be able to show before I have finished. To make the situation understandable to those who are not entirely familiar with the problems of railroad management, and, who feel that the railroads have not moved as rapidly as they should in the direction of greater use of newer materials and newer appliances, I shall have to review briefly the course of recent railroad history. If in this part of my talk I seem to the professional man to be a little off key I feel sure my remarks will be fully appreciated by the business man who cannot understand why he is not making better headway in selling things to the railroads. To do this I shall have to go back to war times for a moment.

Jan 1, 1936

By E. P. Klier, Volker Weiss, George Sachs

IT has been shown that the isothermal transformation of austenite in a special steel can be modified by isothermal holding in the high subcritical transformation range.' Since this treatment potentially leads to increased hardenability, limited testing has been completed to determine if the stabilization effects observed with this treatment can be used to advantage in the heat-treating of 4340 steel. As an index of the effects of the several austenitizing treatments on the hardenability of the steel, Jominy-type hardenability tests were completed for specimens 2.5 in. in diameter and 8 in. long. Since the steel studied is to be used at strength levels where notch sensitivity is of major concern, notch sensitivity after selected austenitizing treatments has been evaluated by notch tensile tests for several specimen sizes. The steel composition and the austenitizing treatments are given in Table I. The test specimens are presented in Fig. 1. The hardenability data are given in Fig. 2 and the notch tensile properties are presented in Fig. 3. The hardenability of the steel investigated when determined by use of the standard Jominy test specimen2 as high and remained essentially unchanged for the different austenitizing treatments. For the larger test specimen, as has been shown by other investigations," the characteristic hardenability indexes are changed and it becomes possible to isolate austenitizing treatments which promote maximum hardenability. The stepped austenitizing treatment promotes higher hardenability as is indicated in Fig. 2. The evaluation of notch sensitivity for very high strength steels is best accomplished by means of the notch tensile test. The experimental conditions of the test, however, modify the notch strengths measured, and in the present experimentation an effort was made to achieve a limiting notch condition by fixing the notch root radius at 0.001 in. while the specimen diameter was allowed to increase from 0.3 to 1.1 in.* For this root radius the notch strength, 0.3-in.-diam specimen, and this trend differs from that for the larger specimens. At the highest tempering temperatures the 1.1-ip.-diam specimens yield comparable results for the austenitizing treatments compared. However, as the tempering temperature is progressively lowered below 800°F, em-

Jan 1, 1958

By Peter Q. Nyce

Law is as old as civilization. In its early stages the so-called law of the jungle, "the survival of the fittest," was entirely operative. Man was quite largely a law unto himself and was likewise his own lawyer. As civilization developed and individuals segregated themselves into bands or communities, man-made laws became a reality, the individual sacrificing certain privileges for the benefit of the band or community in which he was privileged to live. Our present system of law is a continued development of that process. Very early in this development the exigencies of the occasion called into being classes of individuals who were given to study the laws then existing, and this group became known as lawyers. They advised what could or could not be done under existing laws. They were the aggressors in formulating new laws and principles under which the communities must live. Concurrently with the development of the law and the lawyer, the engineering profession was born. In our early civilization, each man was his own engineer; he built his own home, constructed his own bridge, and provided his own means of conveyance. As civilization became more complex, technical study was required to consummate projects and thus meet the requirements of an expanding community. The engineering profession assumed this burden. Both groups were human and thus susceptible to human mistakes and errors. It was Macaulay who said: "The world generally gives its admiration not to the man who does what nobody else ever attempts to do, but to the man who does best what multitudes do well." BiRth of Petroleum Industry In 1859, by the completion of the Drake well in Pennsylvania, the petroleum industry as we know it was born. Its rapid progress since that time has been both extraordinary and remarkable. The zeal of the individual operator to secure all possible oil in the shortest time, even to the extent of bringing into possession a part of the oil underlying a neighbor's property, developed unnecessary drilling, wasteful methods of recovery, great loss of gas, the early abandonment of property with much unrecovered oil thereunder. Such methods, plus

Jan 1, 1931

By R. F. Mehl, W. Batz, C. Wells

L. S. Darken—It is indeed gratifying to find that the results of the two different methods here reported are in substantial agreement with each other and with the earlier work1 of two of the authors. Dr. R. P. Smith, of our laboratory, has been conducting some experiments at 1000°C to determine the diffusivity of carbon in austenite by a third method— the steady state method. This work, which will soon be reported, is far enough advanced that we can say it is in substantial agreement with that of the present authors. The only disparity which might be considered significant is in the high-carbon region, where we find that the diffusivity rises a little less steeply than indicated in fig. 8. F. E. Harris—The authors have presented an impressive arrangement of data concerning the diffusion of carbon in austenite. Of particular interest is the compilation, table IV, which is repeated in col. B of table V for direct comparison with values (col. A. table V) from a formulation using a single Q value of 31,000 cal as the activation energy for diffusion. This comparatively simple formulation has been used quite successfully in the practical application of calculating the carbon added (or removed) through the face in carburizing and decarburizing experiments, where the face concentrations are held quite constant for known times and temperatures. Literally hundreds of tests have been so checked where the computed and experimental values have varied by less than 5 pct. For higher temperatures, where proper carburizing data are hard to obtain, the diffusion couple is treated as a decarburization of the high-concentration bar and as a carburization of the low-carbon member. The analysis has been limited to a maximum of 1.40 wt pct carbon. The agreement between cols. A and B in table V may be considered fair, if a liberal viewpoint is taken. The use of a diffusion couple has one serious drawback, in that comparatively small amounts of carbon pass through planes of concentration close to those of the initial high-carbon and low-carbon members, and hence small errors become important. In addition to the sensitivity at these high and low concentrations.

Jan 1, 1951

By A. B. Kinzel

A PREVIOUS study1 of the relations of impact strength to inclusions showed that the dynamic strength of steel is lowered by the presence of visible counted inclusions, but that other factors comprised in the term "body" have a marked influence. The previous work was carried out on selected steels from a single source, so that the body factor was purposely minimized, but even under these conditions it was found that inclusion counting or the use of the commercial inclusion rating is not satisfactory. The tensile-impact test, however, was indicated as a satisfactory measure of dynamic strength. It was further suggested that the tensile-impact test should be so standardized as to be suitable for use in specifications, and that the hardness factor should be worked out over a sufficient range to admit ready commercial use of the tensile-impact test. In accordance with these suggestions, and in view of the fact that the steels reported in the previous paper were selected and treated so as to have a minimum variation in body, hardness and structure, further work has been performed on a variety of steels which are not limited by these conditions. The word "body" is used here for want of a better term. It is simply a convenient expression which comprises the effect of the various unknown factors that modify the dynamic strength of the steel. Thus at our present state of knowledge, the writers have chosen to consider hardness, structure and counted inclusion content as factors not comprised in the term "body," and such factors as raw materials, process of melting, fabricating, etc. as comprised in the term "body." Numerous grades of steels made in several ways have been taken from different sources and have been heat-treated to varying hardness by normalizing and by quenching and drawing. The results, therefore, may be considered to be generally applicable to current engineering steels. A certain limitation with respect to the hardness at which steel should be

Jan 1, 1931