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By George F. Comstock

It has been reported recently1 that the hardenability and toughness of forging steels may be improved appreciably by the use of complex deoxidizers containing titanium, aluminum, and vanadium. In the light of these results, an investigation of similar deoxidizers containing various hardening and grain-refining elements was proposed. These deoxidizers included three manganese-silicon-aluminum-titanium al- loys with and without boron and calcium, three titanium-aluminum ferroalloys with vanadium, molybdenum and zirconium, respectively, an aluminum-zirconium ferroalloy, and plain ferroboron. Their approximate compositions are given in Table I, and the results obtained so far in the investigation of their effects on steel are presented in the later parts of this paper. Method of Using Deoxidizers The deoxidizers listed in Table I were used in three series of 0.40 per cent carbon steels, which were melted in a small basic-lined induction furnace and cast in the form of I7-lb. ingots about 2.75 in. square. The basic charge for each heat was 10 lb. Armco iron and 6 lb. of clean low-carbon sheet-steel scrap. When melted, this charge was deoxidized with 15 grams of ferrosilicon, then about 500 grams of pig iron was added to give the desired carbon content. After the pig iron was dissolved, nickel shot and high-carbon ferrochromium were added if required, and additions of 80 per cent high-carbon ferromanganese and 50 per cent ferrosilicon were made to provide the proper amounts of those elements. Aluminum was added to every heat 2 min. after the silicon, for grain-size control and preliminary deoxidation. One minute later the special deoxidizer was added to the clean bare surface of the molten steel, and 2 min. afterward the steel was poured into the ingot mold, using a hot-top and pipe-preventing compound after pouring to decrease the depth of the shrinkage cavity. The special deoxidizers were used mostly in the form of about ½ to¾-in. lumps,

Jan 1, 1942

By T. Chen

One of the limitations of the 3-dimensional Lerchs-Grossmann pit optimisation algorithm has been the difficulty in calculating an optimum pit with variable wall slopes. The difficulties have been related to establishing various wall slopes without changing the sizes of the blocks used in the normal computation, but still retaining an optimum solution.

Jan 1, 1977

By William E. Ford, Edward Salisbury Dana

This section includes one distinct group, the Stibnite Group, to which orpiment is related; the other species included stand alone. Pyr., etc. - In the closed tube melts and gives a dark red liquid when hot and a red- dish yellow solid when cold; in the open tube (if heated ver slow? ) sulphurous fumes, and a white crystalline sublimate of arsenic trioxide. B.B. on ciarcoaTburm with a blue Hame, emitting arsenical and sulphurous odors. Soluble in caustic alkalies. Artif. - Realgar is frequently noted as a sublimation product from furnaces roasting ores of arsenic. Crystals are produced when arsenic sulphide is heated in a sealed tube with a solution of sodium bicarbonate. Obs. - Realgar occurs usually in veins associated with silver and lead ores. It has been found in volcanic regions as a sublimation~duct. It has also been noted as a deposit from hot spring waters. It is often rtasociate wlth orplment. It occurs at Felsi5bBnya, Kapnik and NagyAg, Hungary; Allchar, Macedonia. Binnental, Switzerland, in dolomite. In the United States, at Mercur, Utah; in the Norris Geyser Basin, Yellowstone Park, as a deposition from the hot waters. Found at the Monte Cristo millin district, Snohomish Co., Washington: the namerealga7 is from the Arabic, Rahj af gh&r,powder of the mine. Use. - Was used in fireworks to give a brilliant white light when mixed with saltpeter and ignited. The artificial material is now used for this purpose.

Jan 1, 1922

By Jerome J. English, Gordon W. Powell

An experimental investigation and mathematical analysis of the thermal-dilation behavior of the titanium alloy Ti-7Al-3Cb have shown that the linear dimensional changes associated with the polymorphic transformation need not be isotropic. The absolute magnitude of the linear dimensional change, which may be either positiue or negative, associated with the cr-p transformation is dependent upon the relutzve volumes of different orientations of the transformation product. It is hypothesized that the dilation irregulati-ties that have been observed during the polymorphic transformation of pure, coarse-grained titanium and other titanium-base alloys can be explained in the same manner. When titanium is heated above about 165O°F, the hcp a structure transforms to bcc 0. Thermal-dilatioh measurements have shown that the transformation is accompanied by a decrease in length of 0.16 pct.' Such dilation behavior would be expected because the volume of the hcp unit cell is about 0.3 to 0.4 pct greater than that of the bcc unit cell. A recent investigation2 of the thermal-dilation behavior of an experimental a-p* titanium alloy, Ti- 7A1-3Cb, containing 0.06 wt pct 0 showed that its dilation behavior during the polymorphic transformation differed substantially from that reported for unalloyed titanium. The first time the alloy was cycled through the transformation, the dilation curve closely duplicated that of unalloyed titanium. However, upon repeated cycling through the transformation temperature range, both the magnitude and the sign of the dimensional change associated with the transformation were observed to vary with each cycle. This investigation was undertaken to obtain additional data on the dimensional changes associated with the polymorphic transformation in the Ti-7A1-3Cb alloy and to determine the cause of the dimensional irregularities. After testing, the specimens were examined metallo-graphically. In addition, Laue back-reflection patterns were obtained from selected sections taken perpendicular to the specimen axes to determine the a orientations present in these sections. White radiation from a tungsten target and a 0.1-mm-diam collimator were used to produce the diffraction patterns. RESULTS Dilation Curves. Three types of thermal-dilation curves were obtained when the a-8 titanium alloy was heated and cooled through the transformation temperature range. These three types of curves are illustrated in Fig. 1. The type I curve represents what is considered normal behavior, because the dilation change is what would be expected on the basis of the volumes of the unit cells of a and p. The Type I1 curve is the inverse of Type I. Normal behavior is characterized by an expansion on cooling through the transformation, whereas a contraction takes place in the Type 11 curve. With Type ni behavior, no clearly distinguishable length change occurs during the transformation. No other anomalies that might be indicative of other phase transformations were observed in the dilation curves at lower temperatures. Apparently, the cooling rate was low enough for equilibrium to be reached during the 0 to a transformation. Table I lists the types of dilation curves observed during the polymorphic transformation as a function of the direction of measurement and cycle number. The A1 value was determined by extrapolating the low-temperature (a + 5 pct p) and high-temperature (100 pct p) segments of the dilation curves to a common temperature and measuring the difference in the or-dinates at that temperature, see Fig. 1. The transformation occurs over a temperature range in this alloy, so the magnitude of A1 is not an absolute value but depends on the choice of temperature. A mean temperature, T,, within the transformation temperature range was selected for the measurement. T, on cooling occurred about 100°C lower than T, on heating. The first time each of the three dilation specimens was heated to above the temperature, that is, Cycle 2, normal Type I behavior was observed. In Cycle 3, two deviations from normal behavior occurred. First, during cooling of the longitudinal specimen, a substantially larger expansion, +0.21 pct, was measured as 0 transformed to a compared with +0.03 pct in Cycle 2. Second, the thickness specimen was observed to undergo a contraction instead of the anticipated expansion on cooling. Continued cycling of the three specimens from room temperature to 2500°F produced additional changes in the dilation behavior. These changes did not seem to be related to the fabrication direction of the alloy because the values of a1 for the longitudinal, transverse, and thickness specimens varied unpredictably in magnitude and sign. Furthermore, both the longitudinal and transverse specimens showed all three types of dilation curves at least once during the six cycles that they received. Fig. 2 is a sketch of the transverse specimen after

Jan 1, 1967

By Chas. A. R. Lambly

In the extreme northeast corner of the State of Washington, on the Canadian border, lies the Metaline mining district. This district is old in history, but young in production. Geology The Metaline district is a zinc-lead area of the replacement type in dolomite and limestone. The ore bodies of the Josephine horizon are in many ways similar to the ore bodies of the famous Tri-State zinc fields. The beds are faulted and folded and have varying low dips in varying directions, and underlie large areas of the district. History Production started in 1927 on a very limited basis. The property is now mining and milling 700 tons per day. The mine is opened by adit tunnels and a vertical shaft. As the ore horizons gained depth, it was necessary to sink inclines to follow the ore horizon (see Fig 1). From 1927 to date, approximately 600,000 ft of diamond drill was put down This work indicated that suficient tonnage existed to justify a redesigning of the whole operation, surface and underground. After four years of general study, the following program was planned: 1. A new mine entrance, which would be an incline, that could follow the ore body down at whatever pitch was necessary. The incline will be equipped with conveyors for the moving of ore and waste to the surface and with tractor-type locomotives for man and supply transportation. 2. The new incline also required a new type of mining which was developed and is now in use. It is called contour mining and will be described in a future paper. 3. The new incline exit would necessitate the moving of the mill and mine shops across the Pend Oreille River. This part of the program is now underway. The Incline The sinking of the incline was to start as soon as World War II ended and was as follows: The first leg of the incline was to be sunk from the surface 1600 ft on a 17" slope. The collar and first level at elevation 2180 ft, the second level at elevation 2000 ft, the third level at elevation 1875 ft, and the fourth level at elevation 1700 feet. From the 1700 ft elevation the incline was to flatten out to 12" for 400 ft to give the necessary depth for the ore pockets below the 1700 ft level and the necessary clearance for future sinking (see Fig 1 and 2). Due to lack of manpower in 1946, the program was changed and was as follows: A drift was driven from the old mine workings on the 1700 ft elevation in an easterly direction. At 1300 ft the drift was turned N 50" E and at this point a raise was driven 180 ft on a 50" slope. This raise intersected the Josephine horizon and commercial ore was encountered. At the 2000 ft mark, a main raise was driven, 245 ft on a 50" slope, and the 1875 ft elevation was cut. Exploration drifts were started on this level and production followed on a limited basis. The main drift at the 2500 ft point was turned N 35" E and ran parallel to and 10 ft east of and under the proposed incline line. At the proposed intersection of the drift and incline on the 1700 ft elevation, it was planned to raise the incline to intersect the 245 ft raise and to continue on to the surface, a distance of 1600 ft. When this proposed intersection point was reached, a heavy flow of water, approximately 800 gpm, was encountered and all work on the main drift face was stopped. This water flow flooded the main pump station in the old mine and the two lower levels with approximately 20,000,000 gal of water. The water was controlled and finally drained from the cave areas and lower levels after six months of pumping. After the heavy flow of water was encountered in the main heading, it was decided that the incline would have to be started from the surface, as originally planned, so that too much time would not be lost. The surface overburden had to be removed, a total of 6000 yards. A temporary dry house for 6 men was built. An 8 in. churn drill hole was intersected in the first raise driven from the 1700 foot elevation tunnel. Air and water lines were placed in this hole, and air and water were delivered to the collar of the incline from the mine working. The incline started down at 15 ft wide and 7 ft high through the Leadbetter slates. After sinking 4 sets, it was

Jan 1, 1950

By C. C. Singleterry, D. L. Katz

The critical phenomena have been studied during the past century but our knowledge of the critical temperatures and pressures of complex hydrocarbon mixtures still is very limited. The critical temperatures and pressures of pure substances have been examined in large numbers120 and in great detail.11.17 No experimental determinations of the critical phenomena have been reported on such complex hydrocarbon systems as a reservoir fluid. The critical temperature is defined by Taylor18 as follows: "there is some temperature for each gas above which the gas cannot be liquefied. This temperature is called the critical temperature." The critical pressure of a pure substance is the vapor pressure at the critical temperature. It should be noted that these definitions refer to a given substance in the pure state and do not mean that the pure substance cannot be liquefied in the presence of a second constituent. The normal procedure for obtaining the critical temperature of a substance is to heat it in a glass tube 1,20 under pressure until the meniscus between the liquid and vapor phase disappears, although other methods, especially for mixtures, have been used.13,14 However, when considering oil and gas reservoirs, it is more enlightening to consider a critical phenomenon that occurs when a mixture of oil and gas are compressed at a reservoir temperature until the meniscus disappears because the two phases become equal in composition. This conception, along with erroneous applications of the definition of the critical phenomena of a pure substance to that pure substance when it is part of a complex mixture, has caused confusion even among persons familiar with the classical theories. The purpose of this paper is to discuss the critical phenomena of pure substances and mixtures and to report experimental data on a mixture of

Jan 1, 1939

By D. W. Mitchell

Mine fires are a serious hazard; surveys show that the coal-mining industry lags considerably behind industry in general in planning and training for fighting fires, and providing adequate fire-protection facilities. The results of the experiments discussed in this paper emphasize that every effort must be made to extinguish a fire in its incipient stage. The research also demonstrated that extinguishing agents and techniques, superior to those presently used in most operating mines, are available. An underground coal mine fire, if not extinguished quickly, can develop rapidly, create a serious hazard, and cause loss of life and property. The problem of controlling a fire increases in direct relationship to the time interval necessary to initiate control measures; as the fire increases in size and intensity it becomes progressively more difficult to cope with roof control, visibility, ventilation, and explosion prevention. Despite the constant vigilance of the industry, the number of coal mine fires is increasing. During the eight-year period, July 1952 to July 1960, following enactment of the Federal Coal Mine Safety Act, the Bureau of Mines investigated 401 fires that caused 30 fatalities and 75 injuries. More than half of these fires burned for more than one shift; 20 pct could not be extinguished by direct attack and had to be sealed. Agents and techniques for extinguishing simulated mining-machine and underground coal fires have been investigated in the Bureau's experimental coal mine. The research shows that visibility in the fire area is a primary factor affecting control operations. Associated with good visibility is accessibility to the fire; the closer the attack can be made, the less time and quantity of agent are required for extinguishment. Approach to the fire and visibility are hindered by the smoke and hot gases backing up against the ventilating current. In open entries an increase in air velocity assists in driving smoke ahead; at low airspeeds approach can be made by placing a brattice across the lower two-thirds of the entry, pushing the smoke ahead with water sprays, or discharging rock-dust from a rock-dust distributor. In a dead-end entry, fires can be approached by coursing fresh air along an airtight line brattice. However, it is safer, easier,

Jan 1, 1962

By J. Larsen-Badse

The resistance to dry sliding abrasion us been measured for some hardened and tempered carbon steels. The wear resistance, defined as the reciprocal of the volume loss per unit sliding distance, is found to vary linearly with the hardness of the abraded surface. The data fit two lines, one, of high slope, for the pure metals and for the annealed steels and another, of smaller slope, for the hardened and tempered carbon steels. A relationship is developed showing the alwasion resistance to be proportional to the hardness of the material and to en, where n is the exponent of work hardening. The values of n and of the hardness FOR most materials a high resistance to abrasion is generally associated with a high value of indentation hardness. Brine11 even used the abrasion resistance as a measure of hardness in an attempt at expanding the hardness range covered by his indentation-hardness test.' When comparing different types of materials there is, however, only a very general relation between abrasion resistance and hardness. Sample brittleness seems to contribute to the deviation from a direct relationship. In general, increased brittle- are those relating to the heavily deformed abraded surface. However, for materials having n constant or varying m a regular manner over a wide range of strailts, the wear resistance will also be a linear function of the bulk hardness of the material. For tempered steels containing a dispersion of cementite in ferrite the increase in wear resistance due to the dispersion is found to be a linear function of the volume fraction of Fe3C and of the reciprocal of the mean free ferrite path. This indicates indirectly that the yielding of this material, when it is already heavily deformed, follows the Orowan criterion. ness leads to decreased abrasion resistance.' When comparing materials in the same group, e.g., the metals, the spread is less. Kruschov found that the abrasion resistance of pure metals and of annealed steels is directly proportional to the hardness of the metal. For hardened and tempered steels he obtained another linear relationship, one of smaller slope and intersecting the line for the pure metals at the location of the data for the annealed steels. He also found that the abrasion resistance of cold-worked metals is independent of the degree of cold working. This shows, as he concluded, that the process of abrasion work hardens the metal in the surface region to a very high degree.

Jan 1, 1967

By L. L. Wyman

Previous studies1 by the writer dealing with the embrittlement of copper have been concerned with the behavior of various pure and deoxidized coppers when exposed to an oxidation-reduction cycle, and the consequent evaluation of these materials on the basis of their resistance to this action. No attention was devoted to the variations in penetration of embrittlement with time, when these copper materials are exposed to a strong reducing gas, such as hydrogen, nor to the variations in oxygen penetration, with time and temperature, into the "pure" coppers. The cause of the embrittlement is the reduction of the oxygen in the copper by the hot reducing gas, so that a consideration of time, temperature, the occurrence of hydrogen and oxygen must be given. For the purpose of differentiating some of the involved factors, the present work may be divided into two separate series of experiments. The first of these deals with the oxidation of purified coppers under various conditions and then the subjection of these to a standard hydrogen treatment. The second series concerns the reduction, under different conditions, of tough-pitch coppers of several oxygen contents. The resulting data will give the rates of oxidation, and of reduction, for the materials involved. The first series of experiments will reveal how rapidly copper may become oxidized, while the second series will indicate how rapidly embrittlement will penetrate into an oxygen-containing copper when it is exposed to hydrogen at different temperatures. Materials For the purpose of determining these variables, three types of material were selected, to cover the extremes in the ranges of materials commercially obtainable. The first class of materials is represented by an oxygen-free copper, as well as the high-purity vacuum-melted copper2 used in previous work. These materials were selected to determine the variation of oxidation with time and temperature, by oxidizing these coppers under various combinations of these factors, and noting the effect as indicated by a

Jan 1, 1934

Jan 1, 1940

By Carl A. Zapffe, George A. Moore

In a previous publication from this laboratory1 the conclusion was drawn that the embrittling effect of occluded hydrogen on iron and steel must result from the precipitation of the gas within small openings through the crystal structure. A review of the literature then published indicated the real existence of crystal substructures of the mosaic type and gave presumptive evidence that the "rift openings" associated with hydrogen occlusion are the same as the L'disjunctions" of the mosaic theory. Inasmuch as no clear conception of the actual nature of the crystal fragments and openings inherent in these theories has been established, it was considered desirable to obtain direct micrographic evidence of their true configuration. In this direction the standard methods of metallographic attack have proved useless. Recourse was had, therefore, to the direct examination of the surfaces upon which failure by cleavage had resulted from the presence of hydrogen. It was expected that such a surface, unaffected by chemical attack and undis-torted by polishing, would reveal the fine openings penetrated by the gas and thus indicate the real nature of the substructures. Materials Studied In commercial steels, defects caused by hydrogen take various external forms according to such factors as structure and purity, and to the extent to which hydrogen either occludes or produces chemical changes. The present work relates only to the well-known transcrystalline hydrogen embrittlement—-"pickling brittleness "—in which elemental hydrogen occluded within the grain develops cleavage characteristics. For example, hydrogen embrittlement resulting from hydrogen reaction products is excluded from detailed study. It was also desirable, as far as possible, to have the study uncomplicated by other elements which themselves cause brittleness. Three types of iron were used. These included ingot iron, decarburized free-machining steel, and a specially prepared, aluminum-killed, electrolytic iron. This choice allowed a comprehensive selection of unavoidable minor impurities and inclusions, which could subsequently be shown to have no specific effects on the structures within the grains. Carbon, and any other impurities free to react with hydrogen, were first removed by a preliminary annealing treatment in hydrogen. Subsequent treatment in vacuo extracted much of this hydrogen and its gaseous reaction products. The resultant ductile iron was then embrittled either by a second anneal in hydrogen, followed by rapid cooling, or by cathodic electrolysis. Group 1: Prepared from Armco Ingot Iron As shown in Table 1, the principal impurity in this iron was oxygen, which survived the purifying treatment to a large extent. Two series were prepared. The first (Nos. SIO-24) was purified only one day in hydrogen and dehydrogenized one day in nitrogen. Containing both hydrogen and its

Jan 1, 1943

By F. J. Radd, R. L. McGlasson

The mechanisms of corrosion and corrosion fatigue damages to sucker rods are examined from a fundamental electrochemical viewpoint, and the relationships of sucker rod microstructures to these damaging effects are defined. The common corrosive agents in crude oil production and storage are discussed as to types of attacks that they cause. The variations of fatigue strength with alloy content, surface preparation, and stress ranges are analyzed. Finally, conclusions are drawn as to how microstructures largely influence and control sucker rod performance. INTRODUCTION Greater than 90 per cent of the crude oil produced by artificial lift methods is produced through sucker rod pumping systems. In the USA each year more than $14 million is spent for sucker rods in new and old pumping installations. It is important to make this investment a wise one. Essentially, the sucker rod system is a long series of steel rods, operating under alternating stress loadings and under mechanical vibrations, which connect the surface power source with the subsurface pump. These rods often operate in a variety of corrosive media, including water, brines, carbon dioxide, hydrogen sul-fide, and air. Basically, this paper is concerned with the problem of the behavior of certain steels in various corrosive media under high and dynamic stress patterns. The main objective of this paper is to show how, once the stress effects and the corrosive environments are defined, one can still realize structural control and beneficial influence upon corrosion and corrosion fatigue. FUNDAMENTAL DEFINITIONS AND ANALYSIS In the corrosion and stress behavior of this solid state mixture of iron and iron carbide called steel, one must analyze upon what major factors does its service life depend and of what, exactly, is steel composed. The former question can be referred to two external factors and two internal factors. The two major external factors are: 1. the nature of the stress patterns — size and range of stresses present 2. the nature of the corrosion — erosion environment — the corrodent and/or wear involved The two fundamental internal factors that govern the strength and useful life of a steel both in normal duty and in heavy-duty corrosion service are: 1. the nature of the steel volume properties 2. the nature of the steel surface properties For the latter question normal steel is defined as a solid mixture of iron and iron carbide particles, generally with certain accidental and intentional elements present. (The amount of iron carbide present is determined by the carbon content of the steel.) These additional elements generally dissolve into either the iron (ferrite) or the iron carbide (cementite) components.

Jan 1, 1955

By William M. Brewer

Since writing the paper on this subject,* which was presented at the Atlanta meeting in October, 1895, I have had opportunity for more thorough investigations in several localities, and venture, therefore, to offer some additional facts and opinions. The literature of the subject is not very abundant. Dr. George F. Becker's " Reconnaissance of the Gold-Fields of the Southern Appalachians "† contains some brief notes relating to Georgia, but does not include Alabama. The paper of Messrs. Nitze and Wilkens on " Gold-Mining in the Southern Appala-

Jan 1, 1897

By R. S. Dean

The commercial production of electrolytic manganese on a small scale commenced in 1939. The writer made a short report on the progress of production and utilization in Mining and Metallurgy for January 1941. Progress during the last two years, naturally, has been more rapid. In June 1940, Congressman (now Senator) Scrugham presented a proposal to Congress for an appropriation authorizing erection of a pilot plant for " the production of metallic manganese by electrolytic or other means." As a result of this, a pilot plant, having a capacity of a few hundred pounds per day was built at Boulder City, Nev. Subsequent appropriations permitted expansion of the plant to about a ton per day. Much has been learned in this plant about electrolytic manganese, and the product even in its small way has found war uses of considerable importance. Meanwhile, the Knoxville plant of the Electro Manganese Corporation, the sole commercial producer, was expanded to about 4 tons per day to supply needed material for the war program. Other proposals for commercial plants have not been favorably received by the War Production Board. The Bureau reported on one such proposal by the American Alloys and Chemical Corporation. Practice at BouldeR City The present practice, as carried out at Boulder City, which is being described in more detail in a current paper by the Bureau staff at Boulder City, starts with a manganese dioxide ore containing about 20 per cent manganese. Currently this ore comes from the Three Kids deposit near Las Vegas. The steps for the production of electrolytic manganese, in general, are as follows: 1. The manganese in the ore is reduced to MnO. 2. The MnO is dissolved from the ore in spent electrolyte, which contains about 38 to 47 grams per liter of free sulphuric acid, 135 grams per liter of ammonium sulphate, and 10 to 12 grams per liter of Mn as sulphate. In the leaching step the manganese is built back up to 32 to 36 grams per liter of Mn as sulphate; the pH is adjusted to neutral by means of gaseous ammonia and passed through thickeners. 3. The electrolyte is purified by adding H2S, which precipitates the heavy metals. After filtering, ferrous sulphate is added to the solution and oxidized with air and the solution is filtered and clarified on a precoat filter. 4. The purified catholyte is electrolyzed in a diaphragm cell using stainless-steel cathodes and lead-silver anodes. The current density is about 45 amp. per sq. ft. Current efficiencies of 60 to 65 per cent are regularly obtained.

Jan 1, 1944

By E. H. Dix

All commercial aluminum contains small percentages of copper, iron, and silicon as unavoidable impurities. The purest metal obtainable commercially, special grade high purity ingot, contains a maximum of 0.50 per cent. impurities of which the usual minimum amount of copper is 0.01 per cent.; silicon, 0.12 per cent.; and iron, 0.20 per cent. This grade is too costly for most purposes. The two standard grades, Nos. 1 and 2, containing a minimum of 99.0 and 98.0 per cent. aluminum, respectively, are more generally used. Other grades of secondary aluminum often contain as high as 3 or 4 per cent. of impurities, which include 1 per cent., or more, of zinc. Specifications for high-grade aluminum-casting alloys generally allow a maximum of 1.7 per cent. for total impurities. The S. A. E. Specification No. 33, which is intended to cover alloys made from secondary aluminum ingot, gives the iron maximum as 1.5 per cent. and the maximum for silicon (including manganese and tin) as 0.75 per cent. The effect of even relatively small amounts of impurities on the physical properties of ingot aluminum is shown by the following cornparison of two lots of aluminum, which may be taken as representative of special grade and grade No. 2 ingot, respectively. AnalysEs Special Grade, Gbade No. 2, Per Cent. PeR CBnt. Copper................................. 0.01 0.32 Silicon................................. 0.12 0.32 Iron................................... 0.42 0.82 Aluminum.............................. 99.45 98.54

Jan 1, 1923

By W. B. Finkeldey, C. H. Mathewson, C. S. Trewin

This paper was prepared upon request as a contribution to a symposium covering the manufacture, properties, and uses of the important non-ferraus metals. In approaching a subject as broad as this, there is a natural desire to build up a comprehensive and finished production which shall constitute a dependable source of information on all questions properly belonging to this branch of metal technology. There are, however, a number of circumstances, apart from the mere routine of labor and thought involved, which operate rather effectively against the possibility of completing such .an ambitious program at the present time. First of all, as far as any public record of results is concerned, the commercial rolling, drawing, and forming of zinc with relation to changes of structure and properties—and this we consider to constitute the clement~ of metal technology—might as well be an unpractised art. We have never seen a published photomicrograph showing the structural characteristics of either hard or soft sheet or strip, although the structure of castings has been frequently described, and other coarse-grained structures resulting from hard-hammering and annealing have been reproduced. Thus, an author in this field must proceed to his task without much assistance from the literature, and the outcome can represent only a personal estimate of principles, facts, or findings, and not a summary or survey of progress in the entire field as determined by varied experience, practice, and settled opinion.

Jan 1, 1921

By Edgar S. Cook

Portions of this paper repeat in substance the statements made by me in an address before the meeting of the American Society for Testing Materials, held in June, 1903, at Delaware Water Gap, Pa. The views I then expressed, I still hold and believe to be pertinent to the present discussion of this subject. In doing my part, therefore, at the request of our Secretary, towards the further consideration by the Institute of the Physics of Cast-lron from a commercial as well as a theoretical standpoint,—a theme which received interesting treatment in our meeting some years ago, but has been somewhat neglected recently,—I make no apology for reiterating the views I have expressed elsewhere. Indications all point to the substitution of classifying pig-iron by chemical analysis for the old-time method of grading by fracture. Commencing with the larger users, and the makers of specialties, who require more positive information as to the composition than is afforded by the fracture; the use of pig-iron, guided by analysis, has spread with much greater rapidity to all classes of foundry-work than the most sanguine expected. Grading by fracture, as guided by experience with any particular brand of iron, has some points in its favor. The fact that, for so many years, castings of multitudinous forms, and for an endless variety of uses, were made in a fairly satisfactory

Jan 1, 1905

My question relates to tundish nozzle plugging on aluminum-killed heats. North Star has avoided this problem by silicon deoxidation. What has been Inland's experience with this problem on open-pour and submerged nozzle pouring?

Jan 1, 1972

By Emil Gathmann

INTRODUCTION. IN presenting this paper I will attempt to answer certain questions proposed at this meeting and describe and illustrate methods of producing sound steel in an economical and hence commercial manner, which are adaptable to the production of practically all steel manufacturers, by readily effected rational changes in the methods of casting, cooling, and subsequent handling of the ingots. In some of the high-grade mills of America, where it is essential to obtain perfectly sound billets or blooms, it is the practice to discard from 35 to 40 per cent. of the crop- or pipe-end, and even with this excessive discard, secondary pipe or shrinkage-cavities are frequently discovered during subsequent working of the blooms and billets into their various manufactured products. The usual discard of from 10 to 20 per cent. from the crop-end of the ingot, which is made by the present generally employed methods of form and solidifying of the castings, certainly does not give the slightest assurance of the saleable product being physically sound or chemically homogeneous. I am aware that in the past there has been and at the present time there still is a decided difference of expert opinion as to what constitutes physically sound steel.

Jan 4, 1913

By R. H. Pemberton

The principle of airborne electromagnetic prospecting is well-known. The basic geophysical texts in most cases discuss the main elements involved in electromagnetic prospecting. However, there is certainly little information available to the public concerning the present types of airborne electromagnetic systems being flown today by both contracting companies and some of the mining companies which have their own instruments. This is unfortunate since it is difficult for those people not conducting such operations to understand thoroughly the large variation in the electromagnetic instruments available.

Jan 1, 1961