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By G. Sachs, Jr. Brown W. F., Ebert L. J.

It is a generally recognized fact that a steel quenched from the austenitic range and tempered to yield a structure composed of tempered martensite becomes increasingly more ductile with increasing tempering temperature. However, the conventional tensile test fails to yield any value that is sensitive to differences in behavior on tempering among the various low-alloy steels or among different heats of a particular steel. The notched impact bending test, on the other hand, has been recognized for a considerable length of time as capable of revealing differences in impact properties among various steels tempered to 'the same strength level (i.e., the same tensile strength in a conventional tensile test). However, this test is very complex and its significance has not been clarified up to the present time. Of its three characteristic features—the high speed, the notch, and the bending—the notch has been found by Davidenkov2 to be the most potent embrittling factor. Recent investigations on low-alloy steels have shown static notch-bar tensile tests to be more lucid and to evaluate the metal properties in much the same manner as impact tests. In an attempt to analyze the fundamental nature of this test, it was found possible to separate the effects of the two basic characteristics of the stress pattern introduced by the presence of a circumferential notch, the stress state and the high initial stress concentration at the notch bottom. The major conclusions drawn from these previous investigations were as follows: I. The magnitude of the triaxiality at fracture depends primarily on the initial notch depth. Its effect is a great reduction in the average ductility (contraction in area at fracture in the notched section) as compared with that observed in uniaxial tension. This triaxial stress state occurs at a point in the interior of the notch specimen. It determines the notch ductility if the notch is mild and/or the metal possesses a considerable ductility. On the contrary, brittle specimens probably fracture on the metal surface (at the notch bottom) at which point biaxial stress state is present. This biaxiality also considerably reduces the ductility of the metal. For small notch ductilities the notch strength and the notch ductility become very sensitive to embrittling factors. This is contrary to the behavior. of the ductility values derived from a conventional tensile test, which are comparatively insensitive.

Jan 1, 1947

By Ebert L. J., G. Sachs, Jr. Brown W. F.

It is a generally recognized fact that a steel quenched from the austenitic range and tempered to yield a structure composed of tempered martensite becomes increasingly more ductile with increasing tempering temperature. However, the conventional tensile test fails to yield any value that is sensitive to differences in behavior on tempering among the various low-alloy steels or among different heats of a particular steel. The notched impact bending test, on the other hand, has been recognized for a considerable length of time as capable of revealing differences in impact properties among various steels tempered to 'the same strength level (i.e., the same tensile strength in a conventional tensile test). However, this test is very complex and its significance has not been clarified up to the present time. Of its three characteristic features—the high speed, the notch, and the bending—the notch has been found by Davidenkov2 to be the most potent embrittling factor. Recent investigations on low-alloy steels have shown static notch-bar tensile tests to be more lucid and to evaluate the metal properties in much the same manner as impact tests. In an attempt to analyze the fundamental nature of this test, it was found possible to separate the effects of the two basic characteristics of the stress pattern introduced by the presence of a circumferential notch, the stress state and the high initial stress concentration at the notch bottom. The major conclusions drawn from these previous investigations were as follows: I. The magnitude of the triaxiality at fracture depends primarily on the initial notch depth. Its effect is a great reduction in the average ductility (contraction in area at fracture in the notched section) as compared with that observed in uniaxial tension. This triaxial stress state occurs at a point in the interior of the notch specimen. It determines the notch ductility if the notch is mild and/or the metal possesses a considerable ductility. On the contrary, brittle specimens probably fracture on the metal surface (at the notch bottom) at which point biaxial stress state is present. This biaxiality also considerably reduces the ductility of the metal. For small notch ductilities the notch strength and the notch ductility become very sensitive to embrittling factors. This is contrary to the behavior. of the ductility values derived from a conventional tensile test, which are comparatively insensitive.

Jan 1, 1947

By Porter W. Shimer

The solution used in the following method for phosphorns-determination is the filtrate obtained in the nitric and sulphuric acid method for the determination of silicon (Transactions, vii., 346). This filtrate, being easily and quickly obtained, and always quite free from silica, is a desirable one for phosphorus-precipitation. IN order, however, to get all the phosphorus in a precipitable form the solution must be made under conditions more strongly oxidizing than simple solution in boiling nitric acid. In a solution thus

Jan 1, 1889

By S. K. Kawatra, R. A. Seitz

The use of inferential particle sizing for closed wet grinding circuit control has been practiced for several years. This paper presents a review of some inferential sizing equations developed for pilot and industrial plants using regression analysis. An analytical development is then presented showing how the general inferential sizing model arises from the nature of the classifier model. The relation between the general sizing model and the individual equations is then discussed.

Jan 1, 1984

EVERY forward-looking mining company realizes the need for employing graduate mining engineers so that there will be a supply of qualified men from which to draw for company officers, executives, and mine managers. The mining industry is competing today with numerous other fields of engineering for its supply of technical men, many of which are more attractive than mining because of better pay, living conditions, and well- regulated company training programs. The Ontario Mining Association and the mining companies of Ontario are conducting a postgraduate training plan which if adopted in the United States, might well encourage top quality men to study mining.

Jan 3, 1950

By George Asmus

Closed front, or open front for blast-furnaces, has been for a number of years a much discussed question among the furnace-men in every country where iron is made. As blast-furnaces are costly structures, and as the whole question is one of economy, I hope to be excused for entering a little into details. The "fore-hearth" is a prolonged opening in the lowest part of the hearth, from two to three feet wide, four to six feet long, and two to three feet high. It is a more or less fire-proof box, cooler than

By George Asmus

CLOSED front, or open front for blast-furnaces, has been for a number of years a much discussed question among the furnace-men in every country where iron is made. As blast-furnaces are costly structures, and as the whole question is one of economy, I hope to be excused for entering a little into details. The ('fore-hearth " is a prolonged opening in the lowest part of the hearth, from two to three feet wide, four to six feet long, and two to three feet high. It is a more or less fire-proof box, cooler than

Jan 1, 1876

By Raymond E. Riethmann, Beuford M. Bunnell

The spiral classifier was originally developed for closed circuit grinding It has since been applied very successfully to other classification duties where a two-product size split is required. Inherent operational qualities of this classifier make it ideally suited for sizing, washing, or dewatering materials such as ores, phosphate rock, sands, coal, oyster shells, solar and potash salts. Operating characteristics, flexible design and guidelines for proper application are presented.

Jan 1, 1978

POSITIONS VACANT No. 255. A company manufacturing malleable iron fittings in Connecticut needs a manager for its steel department. Experience with converter is essential. No. 256. A prominent mining company in Central America wishes a shift boss for its mill and cyanide plant, who is technically trained, experienced, and can speak Spanish. He should he sufficiently expert to be able to take entire charge of the mill in case of emergency. Salary $150 per month on a two years' contract, with additional allowance for board, lodging and transportation expenses. No. 257. A Mexican copper mining company in the State of Puebla needs an engineer on surveying and mapping and drafting in connection with field construction. Healthy locality. Salary $150 per month.

Jan 1, 1918

By Richard E. Ellwanger

Methods of utilizing flocculents as settling and filter aids for mineral processing slurries are reviewed. Broad chemical classifications and techniques for proper dilution, multiple addition, and combination treatments are discussed. A variety of custom built and commercially available systems for makeup and delivery of flocculents to the application points are in use throughout the mining industry. Those concepts which, in the author's opinion, are particularly important to the successful makeup and we of flocculants are presented in relationship to the available makeup and feed systems. Actual industrial applications are included in the presentation.

Jan 1, 1982

By James Lee Hibbard, Doraiswami Ramkrishna

A population balance model accounting for the transient variations in drop size distributions in a stirred liquid-liquid system is analyzed for its effect on chemical reaction conversion in a stirred, batch reactor. The analysis is applied specifically for phase transfer catalytic reactions, which indicates that transient effects of evolution of drop size distributions may be important in such systems.

Jan 1, 1981

G. M. TAYLOR,* Colorado Springs, Colo.-I do not think the plan outlined in this paper would work at Cripple Creek. Most of our men have had a pretty good education. The Cripple Creek district is a lessee district-I do not think there is one urine operating in Cripple Creek to-day that does not have the leasing system. We have as many men leasing on our property as we have mining and every man who is working for wages is looking for a lease-every man has mined for him-self, he has been his own boss on a lease, either on our own property or on some of the other properties, and it makes a different class of employees.

Jan 12, 1919

By Victor Rudenno

Feasibility studies for mining projects traditionally involve in their final stages a lengthy process of repetitive trial and error discounting, in calculating the discounted cash flow rate of return resulting from the respective yearly after-tax cash flows. Also, probability analysis and sensitivity analysis (in particular) require extensive additional calculations with each change of any project parameter . These inefficient repetitive procedures have two unacceptable results: 1. they are not flexible enough to allow ready analysis of dependent parameters , and 2. they require resort to high-capacity centralised computing facilities with their inherent impersonality, rather than a convenient and available desk calculator - a factor of particular importance to top mining management. Such problems can be overcome if the mining project can be represented by a reasonable straightforward mathematical economic model. The most flexible and appropriate model has been found to be one in which a maximum and minimum value for each of n parameters are supplied to a program which determines a large number of systematic combinations of parameter events and then statistically analyses them to determine the resulting coefficients of the model. In this paper the authors discuss the selection of the most appropriate type of model and outline the steps followed in its development and application.

Jan 1, 1977

By Kenneth L. Cook

The five serpentine masses exposed within the northern half of Riley County, Fig. 1, constitute a major part of the few exposures of igneous rock in Kansas. Although not many subsurface data are available for this part of Riley County, six deep wells indicate that the basement complex lies between 2500 and 3000 ft below the earth's surface. A northwestward-trending ridge in the present basement surface, which extends across the northern half of Riley County, is indicated on Mettner's contour map. The serpentine masses lie in a region that was active during Pennsylvanian and Permian time along two main tectonic trends, which may, in part at least, have developed contemporaneously. One trend is northeasterly, as evidenced by the Nemaha anticline, the Abilene anticline, the Voshell anticline, and many other smaller northeastward-trending folds. The other trend is northwesterly, as evidenced by the central Kansas uplift, the Salina basin syncline, and smaller northwestward-trending folds. The area of the Abilene anticline was actively deformed during much of this time, and the present surface rocks, for the most part Permian in age, show many normal faults

Jan 5, 1955

By J. J. McKetta, O. L. Culberson

A preliminary investigation was made to determine the time required to attain equilibrium within the equilibrium cell for this system. Experimental and smoothed data are presented for the solubility of ethane in water for temperatures of 100°, 160°, 220°, 280" and 340 °F at pressures to 10.000 psia. The minimum solubility phenomenon disappears at 10,000 psia within this temperature range. INTRODUCTION .is a continuation of the investigation of the behavior of hydrocarbon-water systems, the experimental data on the solubility of ethane in water have been extended to 10,000 psia. The experimental apparatus, technique, materials, and analytical methods are essentially the same as previously reported.' TIME-CONCENTRATION STUDY Prior to the initial determinations of solubility in the ethane-water system. it was desired to establish the time

Jan 1, 1950

By H. A. Doerner

METALLURGICAL problems relating to manganese and chromium ores have striking similarities. Ferroalloys, essential to the steel industry, are produced from both ores. Most of these alloys are obtained from imported ores, as domestic deposits have not yielded enough ore of metallurgical grade to meet more than a small fraction of vital needs. A survey of domestic manganese and chrome de- posits reveals numerous small, dispersed bodies of fairly good ore, none of which appears to be capable of yielding significant amounts of marketable products. To stimulate development of such deposits and to increase Government stockpiles, General Services Administration is offering $115 per long ton for limited amounts of chrome ores and $110 per long ton for 48 pct manganese ores that meet metallurgical specifications, with bonuses or penalties for grades above and below specifications.

Jan 4, 1953

By W. V. Kotlensky, H. E. Martens

In an earlier communication, Ref. 1, the authors presented the tensile properties and the changes in crystal structure and microstructure for pyrolytic graphite tested at 2750°C. It was suggested that changes in the structure may have an effect on the tensile properties of this material. Accordingly, tensile tests were run on a series of specimens, from one block of pyrolytic graphite, some of which were hot-worked by being strained at 2750°C, others of which were tested in the as-deposited condition. According to the manufacturer, General Electric Co., the polycrystalline material was deposited at 2100°C on a substrate of synthetic graphite by decomposition of a dilute natural gas mixture. The as-deposited material had a density of approximately 2.19 g per cc, and as shown in Fig. 1 had a structure of medium size growth cones which were regenera-tively nucleated. All specimens had a gage section 0.75 in. long by 0.06 in. wide by 0.1 in. thick with the thickness direction perpendicular to the basal planes. The testing method and equipment used have been previously described, Ref. 2 and 3. For both the hot-working and the testing the load was applied parallel to the basal planes; a cross-head speed of 1.5 x l04 in, per sec was used. All heating was done in an atmosphere of bottled helium.

Jan 1, 1962

By W. E. Glenn

The years immediately ahead-1961, 1962, 1963- will be critical years from every standpoint for the young engineer. In the next few years, he must learn to grow professionally. Most often, the rate and extent of this growth will be governed by his own initiative and perseverance. Habits and attitudes acquired during these early professional years relate very closely to, and even foreshadow, future accomplishments. The future goal of the young engineer is a moving target. It will change with professional growth, family requirements, changes in predominant interest, general economic and business conditions and geographic location. However ambitious and stead-fast in his goal he may be, the young engineer should not hesitate to adjust or change-for he really does not know initially what he is best fitted for and will not know until he has tried a number of things patiently and persistently.

Jan 1, 1961

By Persifor Frazer

The section along the left bank of the Susquehanna, in Lancaster County, from Falmouth to the Maryland line, which the writer made in 1877 to accompany his report on that county, was redrawn by Professor Lesley, as stated in the prefatory'letter to Vol. CCC. (p. x.).* As then stated, neither the numerous data, nor the general features of the structure obtained by the writer, were changed ; but enough was done to make a discrepancy between the text and the section as given; and some important points were made less clear in the published section than they were in the MS. map. Amongst other portions of the section, that between the railroad stations, 1190 to 1224, gives the impression on the published maps of a much too definite superposition. A few words will be devoted to this region in the following communication. There is absolutely no room to doubt the structure for about four miles on .each side of the Tocquan axis. The dips are gentle, and in opposite directions, and the lithological characters constant within ordinary limits of variation, nor do these characters resemble those of the rocks which flank these gneisses and mica schists to the northwest and the southeast. For the same reasons it is evident that the rocks which occur within these eight miles or so, represent an horizon below the basement of the fossiliferous or palaezoic series. Not only have no fossils been found, but their lithologieal characters are unmistakably eozeic. But on the upper and lower margins of this

Jan 1, 1884

By A. B. Young

IT is the he object of this paper to describe a Cottrell treater that was placed in operation, in April, 1919, at the Tooele plant of the International Smelting Co., for the purpose of recovering solids from the gases from the McDougall roasting furnaces. Fundamentally, the treater is simply a flue containing rows of vertical plates, forming the grounded electrode, alternated with rows of small horizontal pipes, forming the negative electrode, with proper provision underneath for taking away collected dust. There are advantages in construction over the more cumbersome types, both the vertical-tube and the vertical-box, particularly in the elimination of heavy supporting columns and massive foundations, giving a much lower first cost. There are no right-angle turns to interfere with gas distribution; consequently there is greater efficiency, or, in other words, a greater volume of gas per minute can be effectively treated. Another advantage of the horizontal installation over the vertical is that the principle of the selective precipitation of the various components of the dust and fume as they pass along the electric field may be utilized. Since the treater has been placed in operation, the results have been quite satisfactory and, in many ways, particularly in regard to the volume of gas that may be treated, have greatly exceeded expectations.

Jan 8, 1920