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By H. R. Wheeler

CREATION of a "committee on promotion of student interest in coal mining" has an encouraging implication for the coal industry. It is indicative that mining men, both in the field and in the educational centers, realize that the problems of the industry require the best talent available. Young men are being invited into coal on the premise that it needs them, that it offers opportunity for creative work and the realization of their objectives. In initiating a movement which purports to meet the objectives of any young man who spends four or five years of his life in college, the industry does so with a full realization of its obligations.

Jan 1, 1940

By George Comstock

IT seems a common opinion among metallographists that all light-gray inclusions seen with the microscope in polished sections of steel are manganese sulphide. Examples of this belief are continually appearing, as for instance in the paper by Dr. Henry Fay on manganese sulphide as a source of danger in steel rails,1 and in Lieutenant-Commander Cook's paper on Metallography of Steel for U S. Naval Ordnance.2 Slate FIG. 1-TRANSVERSE VIEW OF THE EDGE OF A SMALL HOT-ROLLED STEEL ROD. ETCHED WITH PICRIC ACID. X 200. colored inclusions are considered to be silicates, and dove-gray inclusions, manganese sulphide. To show the danger in the latter unqualified assumption, it should be sufficient to examine the edge of any piece of steel that is covered with a fairly thick scale, and that has been polished in such a way as to prevent the scale from breaking away entirely below the polished surface. This can be done by protecting the scaled edge of

Jan 12, 1916

By B. S. Old, E. R. Poor

PRODUCING more steel without major capital investment in new plants is one of the most perplexing difficulties which confront the nation's postwar steel industry. The lack of scrap at a reasonable price results in an especially heavy pressure being brought to bear on the pig-iron production facilities which consist of 245 blast furnaces scattered throughout the country but concentrated most heavily in the Pittsburgh-Chicago area. Present demands exceed the total optimum output of these existing blast-furnace plants. Management hesitates to authorize erection of new plants on a scale sufficient to satisfy 'the demand for pig iron for two main reasons: first, extensive building under the present high costs of construction would greatly increase . the over-all capital investment per ton of iron capacity; and, second, the amount of steel necessary for a major construction program would upset the already tight supply-demand situation. The answer to the problem would then seem to be the development and application of a method which would increase the capacity of existing blast furnaces with a minimum of alterations and expense. Experiments consisting of operating a blast furnace at higher-than-normal top pressures, as proposed by Arthur D. Little, Inc., were carried out by the Republic Steel Corp. initially during World War II, and much more extensively during the past twenty months. The results of the Republics trials indicate that pressure blowing is a solution to the problem of increasing pig-iron capacity without necessitating major changes to existing equipment.

Jan 1, 1948

By James C. M. Li, J. Weertman

James C. M. Li (United States Steel Covp.)—The author has discovered a single analytical relation between the minimum, or the steady-state, creep rate and the applied stress confirming a statement made earlier by orn" that such relation should exist and should reduce to the power law at low-stress levels and to the exponential law at high-stress levels. However, as pointed out by the author, all the available theories of creep are not adequate to explain such a single relation. Inspired by such a statement, I have made a suggestion concerning a possible explanation13 of the new relation. This is based on the concept that the rate-controlling step is the cooperative motion of a short dislocation segment. The nature of and the reason for the cooperation have been discussed13 as well as the reason why the motion of the dislocation could be controlled by the mobility of the short segments. A natural short segment has been proposed13 to be the node formed at the intersection of two dislocations. The reason why the node may contain only a few atoms has not been discussed and the application of the proposed model to all the metals and alloys reported in this paper has not been attempted. It seems appropriate to include these in this discussion. The model was partly inspired by the substructure recently observed in the electron microscope on creep specimens. One such example is shown in Fig. 48 in Darken's Campbell Memorial Lecture. The substructure is a collection of dislocation intersections and irregular networks. No pileups have ever been observed in such specimens. A closer look at the network indicates that one set of dislocations is more straight than the other set sug- gesting that the other set may be mobile in the plane of the net. Since, for the network to survive the creep deformation, some dislocation reaction has to take place at the intersection of the two sets of dislocations, the mobile dislocation, even if it can slip in the plane of the net, will have difficulty in moving at these intersections. To illustrate, an idealized network is shown in Fig. 9. The thin lines represent the set of dislocations which are mobile and can slip in the plane of the net except at the nodes which are formed at the intersection of the two sets of dislocations. The other set of dislocations, represented by the thick lines, may have a Burgers vector which is not parallel to the plane of the net, and therefore may be immobile. Because of this nonparallel Burgers vector, the Burgers vector of the node, which is avectorial sum of the Burgers vectors of the two sets of dislocations, will also be nonparallel to the plane of the net. Therefore, the node cannot slip in the plane of the net and the set of mobile dislocations will have to drag the node along as indicated in Fig. 9. Now the problem is how many atoms could be involved in the nodes. Exact calculation of the length of the node is a difficult task especially since the length should be a steady-state length and not an equilibrium length. An estimate of the equilibrium length can be made by balancing the line tension of all the dislocations. The results would be a small fraction of the length 1 between nodes as shown in Fig. 10. In some instances such a calculation shows that the node will not be formed. But, since the calculation is only approximate, it does not rule out the possibility of the formation of a short node. In other instances the equilibrium length of the node is an appreciable fraction of I. Such a node would

Jan 1, 1963

By Daniel T. Brian, O&apos

Exploration targets and results in the mining industry are commonly summarized in terms of tonnage and grade. Business appraisals require, as additional information, the expected profit or loss implied by the physical summay. The early incorporation of knowledge gained through financial analysis computations can provide a means for economically resolving many common exploration and development problems. Examples of such applications from the activities of exploration planning, reconnaissance, land acquisition, and development planning are presented. While prospecting for mineral deposits, geologists are frequently asked what they hope to find or have found. The response is usually descriptive, such as "50 million tons of 1% copper," and the economic implications are deferred until a capital investment decision is required. At that time, a financial analysis integrating the four analysis components is completed. These components are: 1) Tonnage and Average grade above cutoff grade 2) Capital and operating costs 3) Product value 4) Appropriate profit or loss accounting Close examination of these components reveals that there is no intrinsic reason for avoiding financial analyses at earlier stages in exploration, as long as the uncertainty of the estimate is realized. Tonnage and average grades are commonly estimated at early stages in exploration. For this component, the appropriate cutoff is the major uncertainty. Capital and operating costs are difficult to estimate before detailed quantitative information is available, but estimates useful for the types of applications pertinent to earlier exploration stages are possible. Product value estimates may or may not be difficult, depending on the pricing structure of the particular commodity. A simplified accounting procedure usually may be adopted without introducing any significant loss of validity. This paper describe some of the financial analysis applications which are pertinent during mineral exploration and deposit development. These applications lend additional insight during exploration planning, land acquisition, physical exploration, and development. The examples are oriented toward a hypothetical management investment policy which is based on a single criterion, a minimum 15% discounted cash flow rate of return. In reality, managements use multiple criteria. This simplification is convenient for purposes of presentation and does not invalidate the examples. Computers are useful, but not a requirement, for the applications described. The use of computers provides the results on a more timely basis at costs lower than equivalent manual computations. UNDERLYING PRINCIPLES AND ANALYSIS METHODS Data estimates are subject to uncertainty. The analyst may choose to assess this uncertainty by using one of two principles. Each principle has some advantages. The principle most commonly employed is "assumed certainty." Each financial analysis is based on one set of selected data, which may represent the average estimates, minimum expected conditions, etc. The critical data is identified by making successive calculations, varying the values used. Such studies, called sensitivity analyses, isolate the economic effect of various uncertainties, and guide the allocation of future efforts toward improving the overall accuracy of the analysis. A second principle, "assumed risk," examines the interactive effect of the current uncertainties by qualitatively assigning probability distributions to each data element. These probability distributions indicate the currently appraised chance that a given numerical value will prove to be true. The corresponding procedure, risk analysis, consists of processing many individual financial analyses, each analysis being based on randomly selected numerical values from the probabilistic distributions. The result is a numerical presentation of the uncertainty, but care must be exercised in the interpretation of results. The advantage of this procedure is the direct measurement of economic uncertainty caused by the interaction of uncertain estimates. Kennecott Copper Corp. has developed computer systems for accomplishing sensitivity and risk analyses.

Jan 1, 1970

By Geoffrey Gilbert

A study of specimens shows that the key to both oxidation and enrichment at Duck-town is the behavior of pyrrhotite, which is in part dissolved and in part replaced by marcasite. Enrichment takes place chiefly at the expense of marcasite. THE material that forms the basis of this paper was collected in the spring of 1922, during a ten-day visit to Ducktown by the writer in the company of Prof. L. C. Graton. The time available for the work was far too short to allow anything like a thorough study of the deposits, and structural and stratigraphic questions, though they have an important bearing on the origin of the primary ores, were necessarily left untouched. Attention was focussed on the zone of oxidation and enrichment; and by devoting most of our time to the upper levels, open pits, and old workings, and examining the deeper levels only thoroughly enough to obtain a fair idea of the nature of the primary sulfide ore, we were able to make a reasonably complete survey of the various orebodies. With this field work for a background, the writer later made a study, in the Harvard laboratories, of the specimens obtained during the visit. As some of the facts brought to light by this study appear to be new, it seems worth while to set forth the outstanding features and a proposed explanation of them. Much of the Ducktown material that is obviously of greatest significance, as regards oxidation and enrichment, is soft and crumbly. Notwithstanding the desirability of gaining from such material all possible information as to its mineral composition and textural relationships, but little has heretofore been learned regarding it; but, by suitable preparation of this material in connection with the present study, it has been possible to examine it under the microscope without any disturbance of its texture and about as satisfactorily as if it were hard, fresh ore. The information thus gained has contributed measurably to the results set forth in this paper.

Jan 3, 1924

By A. U. Seybolt

RECENTLY, cases of coexisting ordered and disordered phase equilibria have been reported among face-centered cubic metals,1"3 but not on body-centered cubic systems.4 McQueen and Kuczynski5 showed a single line as the boundary between ordered solid solution of Fe3Al type and corresponding disordered solution in the Fe-A1 phase diagram based mainly on dilatometric and magnetic measurements. Such a single line would indicate a second or higher order transition. or an absence of coexisting order and disorder. The writer found previously a two-phase equilibrium region at 800°C consisting of ordered and disordered solid solutions of Fe3Si in a matrix of approximately 1-6 wt pct Si (Fe3Si is of 14.3 wt pct Si). A similar two-phase region of ordered and disordered Fe3Al solid solutions might be expected if the similarity between Fe3Si and Fe3Si structures hold true. In the present investigation, a wire of 22 at. pct Al, balance Fe and 0.0513 cm in diameter was subjected to electrical resistivity measurement in vacuum as a function of temperature between 300 and 800°C, see Fig. 1. There was excellent agreement between data taken on heating and on cooling: no hysteresis was observed. The Curie temperature was determined to be 640 °C which agrees with the finding by McQueen and Kuczynski.5 But in addition, there were two transitional points in the resistance-temperature plot at 510oC and 400 "C. The former is thought to be a connection with the transition from disordered state to a coexisting order and disordered equilibrium state; while the latter, from such coexisting state to ordered state. Fig. 2 shows a phase diagram where the suggested two-phase region lies between dotted lines. The solid lines are those of McQueen and Kuczynski.5 Since these authors found only a single-phase boundary between ordered and disordered Fe3 Al, it would seem likely that the dilatometric method used by these authors was not sufficiently sensitive to resolve the ordering reaction into the two-phase boundaries. In addition, their phase diagram conflicts with the statement they make on P. 1 of their paper: "The sharpness of the peaks indicates that ordering to Fe3A1 is a first order reaction." The suggestion of coexisting order plus disorder in Fe3A1 must be considered tentative until confirmed by high-temperature X-ray examination. If

Jan 1, 1961

About 1300 members and guests attended the Seventh Annual Mid-winter Convention of the American Institute of Electrical Engineers, which was held in the Engineering Societies' Building, New York, on Feb. 19 to 21. The opening session was a joint session with the American Institute of Mining Engineers, when welding was discussed. The various phases of standardization in engineering work were discussed by President Comfort A. Adams at the Thursday morning session. Thursday afternoon was spent in visiting. Some of the guests visited the Brooklyn Navy Yards, where they inspected the power plant, shops, dry, docks, etc. ; others visited the Bell System Laboratories of the Western Electric Co. The papers at the various technical sessions provoked considerable

Jan 4, 1919

By K. Sallmann

Spurred by a variety of factors, coal flotation is making headway among the preparation plants of West Germany. The author gives some statistics on German coal flotation plants and information on the properties of the feed and quality of the derived products. Types of machines and reagents used, dewatering practices, tailings disposal, and thickening operations are covered. There is special emphasis on the many-sided problems that confront German coal preparation engineers. The coal mining industry of West Germany is concentrated in three coalfields: the first on the Ruhr and the Rhein rivers, the second on the Saar river, and the third near the frontier between Germany and the Netherlands, around the towns of Aachen and Erkelenz. The total run-of-mine production of these three coalfields amounts to 736,000 tpd which come from 145 collieries. There are 121 washeries, 43 of them with a flotation plant. The total throughput of these 43 washeries is 280,000 tpd, out of which 26,000 tons (9.3 pet of the washery feed coal) are cleaned by flotation. The capacity of the individual flotation plants varies within relatively wide limits, the average being 40 tph and the capacity of the largest flotation plant being 120 tph. During the last few years, the number and size of flotation plants have been steadily increasing, although flotation must be looked upon as an expensive and rather complex cleaning process. The considerations which have led to the widespread application of flotation may be summarized as follows: 1) In making coking coal, it is seldom possible to add uncleaned fines to the coke oven charge, as their ash content is too high. If, however, the ash content of the fines is reduced to a maximum of 7 or 8 pet, they can be admixed to the washed and crushed small sizes without difficulty. This means, naturally that revenue is increased since the price of coking fines is always higher than the price for dust or uncleaned wet fines. 2) To prevent silicosis and pneumoconiosis, water infusion and spraying of the coal are practiced much more today than ever before. As a result, moisture content of run-of-mine coal has markedly increased and the washery feed coal contains more and more slurry instead of dry dust. The price of slurry, how- ever, is very low, and in many cases it is impossible to sell filtered raw slurry with a moisture content of 20 to 25 pct and, at the same time, 20 to 25 pct of ash. Reduction of the ash content of these slurries improves the possibility of dewatering them and, in this way, also enhances the marketability of this product. 3) The new severe laws and regulations against pollution of air and rivers make it necessary to de-dust coal better than in the past and to reduce the quantity of the waste water from coal preparation plants and their solids content to a minimum. 4) Even if there were no compulsory reasons to clean the fines, flotation will often lead to an increase in the overall yield. Although not the only application, it appears that the treatment of coking fines is the primary field for the flotation process in coal preparation. It must not be overlooked, however, that a series of arguments may be advanced against flotation: 1) Flotation is an expensive process because, in addition to the cleaning operation itself, the dewatering of the froth and the disposal of the tailings is very costly. 2) Operation of a flotation plant requires well trained personnel. 3) Filtered froth has about a 20 pct moisture content and, therefore, if mixed with the cleaned small coal it causes an undesirable increase in water content of the coke oven charge. For this reason it is necessary to take additional measures for dewatering washed small coal and this, of course, entails additional expense. 4) Disposal of flotation tailings involves very difficult problems, particularly in the highly industrialized regions. An investigation covering 32 flotation plants of Western Germany shows the following composition and properties of their feed:

Jan 1, 1961

By G. J. W. Kor, F. D. Richardson

The sulfide capacities a1 1500°C of slags in the systern CaO + CaF, +Al2O3 have been measured by bringing samples into equilibrium with gas mixtures made from CO + CO2 + SO, + N2. The capacities are negligzble both JOY CaF, and CaF, + Al2O3 melts but when lime is present even at 20 wt pct capacilies as high as 30 x lom3 can be obtained. The results have yielded information concerning the liquidus at 1500°C and fluoride-oxide melts in general. The slags used in electroslag refining contain substantial amounts of calcium fluoride. Robinson and Grainger' report that good results can be obtained by using slags of the approximate composition 70 wt pct CaF2 + 30 pct Al2O3. It has also been reported2 that a mixture of 50 pct CaF2 + 30 pct A12O3 + 20 pct CaO makes a good slag for general use. In view of the fact that very low sulfur contents are claimed for ingots produced by the electroslag process. studies have been made of the sulfide capacities [c, = wt pct S (PO2/Ps2)1/2 at 1500°C. of slags consisting of pure calcium fluoride, and of its mixtures with lime and/or alumina. These studies have also provided information on the phase diagrams. The slags were brought into equilibrium with gas mixtures prepared from NZ + CO + CO2 + SO2. Because CaFz is volatile and also easily hydrolyzed. measurements were made of its loss in weight in various flowing gas mixtures. EXPERIMENTAL Procedure. The apparatus and procedure were the same as described previously. Both platinum and iridium crucibles were used (height and inner diameter about 1 cm), but those made from iridium were stronger and able to withstand a greater number of experiments. In each experiment two crucibles were set in an alumina support and 1 g of slag mixture was divided between them. The materials from each crucible were analyzed separately after being brought to equilibrium with the gas, and then quenched in the water-cooled end of the reaction tube. Materials. Alumina and lime were prepared as de-scribed previously.4 Calcium fluoride was obtained by igniting Analar calcium fluoride in a platinum boat at about 800°C in a stream of pure dry nitrogen: the product was cooled in a desiccator. The slags were produced from mixtures of the powdered constituents, these being melted together in the course of each equilibrium experiment. The sulfur analyses and the X-ray diffraction meas- urements on the solidified slags were made as described previously.4 From the latter it appears that the CaF2 contained less than 0.5 mol pct CaO. RESULTS Values of (ps2/po2) for the Gas Mixtures. The re-sults have been represented in terms of (ps, /Po,)"? for the various gas mixtures used. The va1;es of this function at 1500°C are listed in Table I: they were calculated from the data cited previously for calculations at 1350°C 4 Weight Losses with CaF, and CaF, + CaO. The re-sults of the weight loss measurements* at 1500°C for

Jan 1, 1970

By E. R. Morgan

A series of manganese-rich ferromagnetic alloys has been studied. The alloys are based upon an interstitial solution of carbon in manganese. In each of the systems investigated, the ferromagnetic phase was found to be face-centered-cubic in structure. This magnetic phase is based upon the composition (Mn, X)4C; where X is a metallic element which has both a positive size factor with respect to manganese and a high positive valence. Typical elements of this type are aluminum, indium, and tin. Preliminary magnetic measurements indicate that the effective magnetic moment of manganese in the alloys is at least 1.0 Bohr magneton per atom. It is emphasized that the critical atomic separation beyond which ferromagnetism can occur will be governed by the electronic configuration of the manganese atoms. Lattice parameter measurements show that the ferromagnetic condition in the present alloys is associated with an increased atomic separation of only 3 to 6 pct compared with a hypothetical face-centered-cubic lattice of pure manganese. MANGANESE which is paramagnetic and not ferromagnetic in the pure state can become ferromagnetic if suitably alloyed. Under favorable conditions manganese can have an effective ferromagnetic moment of the order of 3.41,2 or even 4.0 compared with a moment of 2.2 Bohr magnetons for iron. The incidence of ferromagnetism is believed to be controlled by the degree of atomic separation.4,5 This is consistent with the fact that the atomic separation, when considered in terms of the ratio of the atomic diameter R to the diameter r of the 3d-shell, is larger in the ferromagnetic metals. The values of R/r calculated by Slater,' for metals of the iron group are given in Table I, and Slater has suggested that the critical ratio of R/r is 1.5. Consideration of the criterion of atomic separation alone would suggest that there are three classes of possible ferromagnetic manganese alloys: 1— Ordered structures, of either solution or compound types, such that manganese atoms are not near neighbors; 2—Structures in which the separation of near-neighbor manganese atoms is sufficiently increased by the presence of suitable solute atoms; and 3—Dilute solutions of manganese. Typical ferro- magnetic alloys of types 1 and 2 are the Heusler alloys and Mn4N, respectively. There are no recognized ferromagnetic alloys of type 3. In view of the proximity of the ratio R/r for manganese to the critical ratio of 1.5, the present work was concentrated on manganese-rich alloys rather than on ferromagnetic alloys of low manganese content, several examples of which are already known. Calculation of the distance of closest approach of manganese atoms in each of its allotropic forms, Table 11, indicates that the high temperature ? phase provides the most suitable basis for ferromagnetic alloys of high manganese content. However the high temperature forms of pure manganese cannot be retained on quenching, although a face-centered-tetragonal form apparently can be produced by electrodeposition. Since the critical separation which must be exceeded in order to obtain ferromagnetism is dependent upon the number of electrons in the d-shell, no exact critical value of R/r can be assumed. Not only will this separation vary from one pure metal to another, but it will also vary with the valency of the given type of atom when it is in an alloy. Raynor8 has shown that metals of the iron group probably

Jan 1, 1955

THE Institute assembled in Packer Hall of the Lehigh University, the President, Mr. David Thomas, of Catasauqua in the chair. Professor Henry Coppée, President of the Lehigh University, made an address of welcome to the Institute, and placed at its disposal a convenient hall for purposes of meeting. Mr. Thomas tendered his resignation as President of the Institute, as advancing years prevented him from actively participating in its meetings. The Institute declined to accept the resignation, and, on the assurance that active duties would not be expected of him, Mr. Thomas was induced to withdraw it. Invitations were received from Mr. B. C. Webster, President of the Lehigh Zinc Company, to visit the mines and works of the company; from Mr. Charles Brodhead, to visit the Chapman Slate Quarries; and from the Lehigh Coal and Navigation Company, to visit their works at Summit Hill and Mauch Chunk and the Nesquehoning Tunnel. The Council reported the names of persons already elected in the two classes of members and associates. The following resolutions were passed : Resolved, That a committee of three be appointed, who shall take into consideration the printing and publishing of papers originating with the Institute, and that a uniform system as regards size and execution be adopted. The committee appointed consisted of Messrs. R. W. Raymond, E. B. Coxe, and the Secretary. Resolved, That the Council design and prepare a seal for the Institute at the earliest practicable time. Resolved, That a committee of six, with power to add to its numbers, be appointed to examine into the question of the more economical production of iron in this country. The committee appointed consisted of Messrs. G. W. Maynard,

By L. Mair

A STUDY by J. R. Low, Jr.1 on the effect of quench aging on the Charpy-impact specimens of semikilled 1020 steel disclosed that a decrease in cooling rate from 1275°F raised the transition temperature. This was demonstrated in his investigation by controlling the cooling rate of impact specimens to duplicate that of a heavier plate and com- paring the properties with air-cooled specimens and quenched specimens. The transition temperature of the samples that had been cooled at a rate estimated to be similar to that of an air-cooled 3/4 in. plate was approximately 45ºF higher than the quenched samples. The transition temperature of the air-cooled series was between that of the slow-cooled and the quenched series. On the basis of this work, it appeared that the cooling rate of plates after rolling in a hot mill would have a bearing on the brittle fracture of the

Jan 1, 1955

By J. E. Campbell, A. W. Wesner, M. Pobereskin

This paper summarizes the results of an investigation sponsored by The Coates Steel Products Company. The objective was to determine the relative effects of certain chemical and physical properties on the wear resistance of grinding balls when grinding cement. In making this study, a number of types of balls were used in both dry and wet grinding in commercial ball mills. The radioactive-tracer technique was used in separating the test balls from the rest of the mill charge and in sorting the different types of halls that were all tested at the same time for each of the grinding operations. PROCESSING OF GRINDING BALLS In order to determine whether the properties of grinding balls, namely, composition, microstructure and hardness, can be related to the rate of wear, the halls used in this study were selected to represent various combinations of these properties. It was recognized that the mechanism of wear was not the same in the wet mill as in the dry mill. Therefore, the types of balls tested in each of the two environments were not necessarily the same. However, all of the types of balls evaluated in the dry mill were tested simultaneously for one time period, while those evaluated in the wet mill were tested simultaneously for three different time periods. All of the test balls were separated from the charge when the mill was dumped. All of the balls were of 0.940-inch diameter when charged, and all but the regular production balls were finish ground to this size to eliminate the decarburized surface layers. The steels and processing methods used, as well as the micro-structures and hardness levels of the balls, are described as follows: Regular production forged SAE 1095 steel balls were used in both the wet and dry mills. They were forged to a nominal diameter of 0.940 inch and quenched in oil from the forging temperature. Each retained a partially decarburized surface layer from the forging bar stock; the maximum depth of this layer was about 0.030 inch and the decarburization was negligible where the ball was sheared from the bar. The hardness at the surface was 40 to 46 Rock-well C in the partially decarburized area and 57 to 62 Rockwell C in the areas not decarburized. The hardened zone extended to a depth of about one-third of the radius. Below the decarburized layer, the hardened zone consisted primarily of hard as-quenched martensite with varying amounts of retained austenite. This structure changed to fine pearlite at a depth of about one-third of the radius. In order to eliminate the effect of the decarburized layer, a set of production balls of SAE 1095 steel was forged to about a 1-inch diameter, quenched in oil from the forging temperature, and ground on ball-bearing grinding equipment to a 0.940-inch diameter to remove the decarburized layer. The balls' hardened zones were similar to those in the previous set. The hardness of the finished surfaces was 52 to 60 Rockwell C. A slight amount of decarburization apparently remained after the removal of about 0.030 inch from the surface. Balls of this type were tested in the dry mill only. Another set of forged SAE 1095 steel balls of 1-inch diameter was heated to 1500 F and quenched

Jan 1, 1961

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Jan 1, 1907

By C. N. Kravig

STANDARD raises at Homestake are 150 ft long. Raises of more than 150 ft, driven with the use of a cage and hoist, are considered long raises- some have been driven more than 900 ft. Long raises have eliminated the need for access drifts on each level when transfer and ventilation raises are driven. These timbered cage raises, 7x9 ft in cross section, include a rock compartment and a combination cage, pipe, and manway compartment. To prevent excessive weight on the timbers, 10x10-in. bearing beams are cemented into hitches cut in the rock at 150-ft intervals. The beams also hold back timber movement caused by daily drawing of rock through the rock compartment.

Jan 6, 1957

By H. C. Chao, Y. E. Smith, L. H. Van Vlack

ThE phase relationships for the MnO-MnS system have been investigated only in the eutectic region. wentrupl reported a eutectic at 1280°C (2345°F) with approximately 50 wt pct of each component, as based on the earlier work of Andrew, Maddocks, and Fowler.2 More recently silverman3 corrected these figures to 2275° ±10°F (1246°C) with 63 wt pct MnS and 37 pct MnO. Neither Wentrup nor Silverman investigated the solid-solution limits in this system. However, Wentrup did suggest with his phase diagram sketch that the maximum solubility of MnS in MnO is 10 wt pct, and the solubility of MnO in MnS is nearer 20 wt pct, Fig. 1. These figures have been utilized in subsequent publications without further verification.4 There had been evidence found in this laboratory that the above solid-solution figures were high. An investigation was therefore conducted using the following procedure. Samples containing MnO and MnS were contained in platinum foil, heated just above the eutectic temperature in a purified nitrogen at- mosphere, and quenched into distilled water. The MnO had been prepared by calcining reagent grade MnCO3 in nitrogen at 1400°C. Only MnO was detected in subsequent X-ray diffraction analyses. The MnS had been prepared by sulfur deoxidation of reagent grade MnSO4 according to the reaction: MnSO4 + S2 ? MnS + 2SO2 The details of the sulfide preparation procedure, which utilized atmospheric sulfur pressures at 950°C, are discussed elsewhere.5 The sulfur content of the sulfide was determined to be 36.8 * 0.2 pct, which matches the stoichiometric value of 36.9 pct. No evidence of either MnO or MnSO4 was detected microscopically or by X-ray diffraction. The single-phase combinations of MnO and MnS at the eutectic temperature indicate the limit of solid solution as shown in Fig. 2(a) and (c), and the revised phase diagram is shown in Fig. 2(d). The melting temperature for MnO is that provided by Glasser.6 The eutectic temperature of 1232° ± 5°C and eutectic composition of 64 wt pct MnS are in close agreement with Silverman's correction of Wentrup's work. The maximum solubility of MnO in MnS was determined to be 1.7 ± 0.2 wt pct. The maximum solubility of MnS in MnO was determined to be 1.8 ± 0.2 wt pct. These figures represent the lower limit for the presence of liquid at 1260°C and are significantly lower than the earlier estimated solid-solution figures. The authors wish to acknowledge the support of U.S. Steel's Edgar C. Bain Laboratory for Fundamental Research. The comments and critical suggestions of Drs. A. S. Keh, R. Rickett, and R. B. Snow are appreciated.

Jan 1, 1963

By Francis Lucas

EACH year we gather in this auditorium to honor the memory of a. distinguished American metallurgist and educator. I cannot bring to you reminiscences of Prof. Henry Marion Howe as other lecturers have done. It was not my good fortune to enjoy the-privilege of studying and working under his direction. As I have reflected on the published works of Professor Howe, it has seemed to me that his mind was trained on the nature of metals and on the mechanism which produced known but unexplained effects. He was interested in controlling and regulating the causes so as to produce specific effects, useful in serving mankind. I recall an afternoon in May, 1925, when, at the invitation of Mrs. Howe, I visited his former home, Green Peace at Bedford Hills, N. Y. The purpose of my visit was to receive at the hands of the widow an engraving of Professor Howe, a reproduction of a painting from life. Mrs. Howe showed me his study. The walls of this large attractive room, brilliantly illuminated by the spring sunshine, were literally covered with the scrolls of honors and of decorations which had been conferred on Professor Howe by governments, academies, universities, societies and institutions the world over. As we walked about the room, she pointed out the significance of each honor and recited a few details of each occasion. I sensed the pride with which Mrs. Howe, then in the late autumn of her life, told me of her husbands' achievements, of his struggles, of his disappointments and of his successes. There was a surprisingly familiar note in the recital to which I was listening. I 'have found the same theme running as a disconnected thread through the written accounts of the lives of most men of science. We then went to the drawing room to chat for a few minutes before I said my farewells. As we seated ourselves, Mrs. Howe turned to me and asked: "Mr. Lucas, what of this great microscope of yours? Cannot it be applied to the study of disease? What a great blessing it would be if it could be directed to relieve the suffering of mankind."

Jan 1, 1931

By W. C. Phalen

The production of salt in the United States divides itself at the outset into two distinct classes…

Jan 1, 1915

By AIME AIME

T HE Board of Directors of the A. I. M. E. held a meeting at Institute headquarters on Jan. 28, 1921. There were present 10 directors and 14 guests, the secretary and the assistant secretary. The following actions of the Executive and Finance Committees were approved: Wilkes-Barre Meeting, Sept. 12 to 17, 1921; authorization of Oregon Section; authorization of Upper Peninsula Section; appointment of Philip W. Henry and Thomas H. Leggett on special committee on Code of Ethics; and presentation of five copies of Raymond Memorial Volume to T. A. Rickard, who edited it. The By-Laws of the Ohio Section were approved. The resolutions in reference to the payment of certain contributions and assessments to the Library Board of the United Engineering Societies, adopted by the Board of Directors on June 27, 1919, were rescinded, and the resolution adopted that the income of the James Douglas Trust of $100,000 be paid over to the Library or otherwise applied by it for the purpose of maintaining the Scientific Library of this Institute in such manner as may be deemed advisable in furtherance of the purposes of such trust, and that said income shall be paid on account of and included in. the assessment levied by the United Engineering Societies on the Institute for the maintenance of the joint libraries of the Founder Societies.

Jan 1, 1921