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By Thunaes, Arvid

Pilot plant test work in 1942 and 1943 showed that by a combination of desliming, fine-size classification, and Sullivan deck concentration it is possible to recover heavy minerals such as cassiterite at least as fine as 10 microns in size. This appreciable improvement in gravity concentration practice has been substantiated by several full-sized plants.

Jan 1, 1950

By Homer Staley

THE casting alloy 88 copper, 10 tin, 2 zinc, commonly known in England as Admiralty metal and in this country as Government bronze, gun metal, or Naval Department composition G, has, at its best, many valuable properties. However, its physical properties are known to vary widely with slight changes in method of manufacture of the castings, such as slight variations in composition, variation in pouring temperature, kind of mold used, method of pouring and gating of molds, size and shape of castings, amount and kind of heat treatment., and so forth.1 The microstructure of castings made from this alloy is influenced by slight variations of composition, rate of cooling, and kind and length of heat treatment. This is best understood by reference to the equilibrium diagram. The part of the diagram in which we are interested and the effect of the thermal equilibrium relations on the physical properties of the alloy 88 copper, 10 tin, 2 zinc, have been discussed by Hoyt, Camp-bell, Primrose, and Rawdon.2 In Fig. 1 is given the equilibrium diagram of the copper-tin alloys. Briefly stated, the relations of composition and temperature changes are as follows. Compositions between A and a consist of but one constituent-the a bronze, which is a, solid solution of copper and tin, rich in copper. On cooling from the molten state these compositions gradually crystallize, at temperatures above 790°, into a mass of interwoven tree-like crystals or dendrites. The cores of the dendrites are rich in copper and the percentage of tin gradually increases as the surfaces are approached. As cooling progresses, after all the metal has crystallized, no further changes occur, in the crystals other than diffusion within the crys-

Jan 9, 1919

By P. Shahinian, M. R. Achter

In a comparison of the creep -rupture properties of nickel in air arid in vacuum there is a reversal in relative strengths with variations in stress. At low stresses the properties are better in air while at high stresses they are better in vacuum. In the early stages of creep in a high stress test the specimen in air nzay have the lower creep rate but the one in vacuum is creeping at a lower rate in the later stages. A mechanism, involving two competing processes in terms of oxidation strengthening and weakening by surface-energy reduction, is proposed to explain these reversals. It had generally been assumed that, relative to their properties in air, the high-temperature strengths of metals would be increased in an inert atmosphere as a result of the elimination of the deteriorating effects of oxidation. However, several recent investigations have shown that the creep strength may be greater in air than in nonoxidizing gases. Pickus and Parker1 found that the creep rate of nickel was lower in air than in hydrogen or nitrogen. Internal oxidation was mentioned by Shepard and Schalliol as a possible cause for the longer creep life of Hastelloy C in air than in vacuum or helium. Sweetland and Parker, who observed lower creep rates for aluminum and copper in air than in helium, discuss the possible applicability of the dislocation-barrier mechanism to explain their results. Surface oxide layers may interfere with the escape of dislocations through the surface or with their generation there. In addition to showing the strengthening in air of low-alloy and stainless steel, and nickel and cobalt-base alloys, shahinian4 presented notch-effect data which indicate the role of stress concentrations; alloys of relatively low ductility were more sensitive to atmosphere strengthening when notched specimens were used. Although Bleakney's copper wires had a lower reduction of area in air than in vacuum, it is difficult to interpret his results in terms of strength changes since the stresses employed were not measured. In contrast to these data showing the strengthening in air, a number of investigations, most at relatively low temperatures, have demonstrated that the environment may cause a decrease in strength. These results are generally explained in terms of the effect of environment on surface energy. In a review of the subject, Benedicks and Harden use the concept of atomic bonding to explain how the adsorption of impurities would decrease the energy of a clean surface. A decrease in surface energy would facilitate the propagation of cracks or extension of the surface. Use of this mechanism is made by sato7 to explain the weakening of steel specimens bent in various liquids, by Potek and Shcheglakovs for the reduction of fracture strength of steel in molten metal, and by Benedicks and Harden for the reduction of strength of a variety of materials in a number of liquids. A similar explanation might be used for the results of Forestier and Clauss. The fracture stress of fine wires pulled in a variety of gases, including air, is lower than in vacuum. They attributed their results to the "tendency" for the gases to condense on the metal surface. That the strength of metals is affected by the type of gas in which the test is conducted has been demonstrated convincingly; the mechanism of the effect, however, is still uncertain. This investigation represents one in a series to explore the influence of variations in alloy composition and test conditions on the atmosphere effect in the expectation that the results would afford an insight into the processes taking place. To determine the effect of specimen composition, the present investigation was conducted

Jan 1, 1960

By John B. Gayle

PRESENT flotation processes depend almost entirely on the buoyant properties of air bubbles to effect separations of mineral and gangue, but there is no convenient method for measuring aeration in flotation cells. Consequently the relation between aeration and cell performance has not been definitely established. In connection with a comparative study of kerosene and froth flotation processes, a modification of the displacement method' was developed in which air escaping from the cell surface is measured with a wet-test meter. The arrangement shown in Fig. 1 is satisfactory for use with a number of cells and is not critical, except that care must be taken to use connections and tubing large enough to avoid excessive back pressures. Attempts to use smaller tubing resulted in back pressures that caused displacement of the liquid level in the receiver, so that some air was lost around the sides, an occurrence readily visible when measurements were taken with only water passing through the cell. With the arrangement shown, the manometer indicated an average reading of about ½ -in. water pressure. No loss of air was evident.

Jan 7, 1958

By E. van Walsum

Tunneling methods through rock have, since the successful development of explosives, relied almost solely on blasting. Over the last ten years, rock-tunneling machines (moles) have been developed and some major projects have been carried out successfully with the use of such machines, which rely on the destruction of rock by mechanical means rather than blasting. Various other basically new methods are presently under study, such as the use of laser beams, water jets, etc. For practical purposes, there are presently only two methods commercially available: 1) blasting or 2) tunneling by mole. A contractor would choose at present either one method or the other. Both methods have their advantages and disadvantages (Fig. 1). The thought has occurred that the next practical development in rock- tunneling technology might be a combination of the best features of the mole technique and those of the blasting technique. A preliminary evaluation of this approach indicated that there is definitely a good potential for fruitful developments along these lines. My purpose is to place on record some of the thinking and some of the ideas which were developed along these lines and to point out certain areas where development efforts are required. In trying to find an improved tunneling technique, we looked in particular for the following qualities: 1) safety, 2) continuity, 3) uniformity, 4) automation, and 5) flexibility. TUNNELING BY BLASTING Conventional tunneling by means of blasting proceeds generally in recurring sequences of events: 1) drilling, 2) loading, 3) firing, 4) mucking-out, and supplementary operations (such as scaling and lining). These four operations (drilling, loading, firing, mucking) proceed one after another.

Jan 1, 1970

By Zay Jeffries

AMONG the various metals with low specific gravity, two, aluminum and magnesium, are used in the nearly pure state or as bases for light-weight alloys. Although the production of magnesium is only about one-twenty-fifth that of aluminum, a higher percentage of its output is used in the transportation industry than that of any other metal. The per-centage varies from year to year but, on the average, more than three-fourths of the magnesium production has been used for this purpose. In the United States, about 40 per cent of the aluminum production is used for transportation purposes. It seems obvious that equipment demanding repeated movement with need for rapid acceleration and deceleration should be as light in weight as the economics of engineering materials will permit. There are, however, differences of opinion with reference to both the economics and the engineering aspects of this subject. Tables 1 to 7 inclusive relate to the principal light-metal materials currently used in the transportation industry. These, with the accom-panying titles and footnotes, are in the main self-explanatory. Although the variations in mechanical properties can be easily seen from the tables, it should be kept in mind that the values given are for ordinary tempera-tures and that the changes in properties with temperature are not the same for the different alloys. Also, the corrosion properties cannot be deduced accurately either from the compositions or from the physical properties. Again, certain of these alloys are used because they possess desirable combinations of properties not listed in tine tables, including heat conductivity, coefficient of expansion, machinability, ease of casting or working, light reflectivity, anodic coating characteristics, etc. These, together with variations in prices, must be given careful analysis to effec-tively utilize the light alloys. Some of the alloys listed in the tables are new and some are old, but all are standard. Even the older alloys are available in new shapes and larger sizes than heretofore, and all are used in the transportation industry in structures of new design. Certain of the applications of specific alloys will be touched upon in the following brief history of the use of the light metals in transportation.

Jan 1, 1936

By F. A. Forward, A. H. Ross, J. Halpern

Application of the carbonate leaching process to carno-tite ores has often been limited by the difficulty of obtaining simultaneous high recoveries of uranium and vanadium. The chemical aspects of this problem are discussed and the effect of prior roasting procedures on this discovery is described. IN treating carnotite ores by carbonate leaching it is often necessary to subject the ore to a prior roast. Among the advantages that may result from roasting are: 1) improvement in settling and filtering characteristics of the ore; 2) destruction of carbonaceous impurities that would otherwise contaminate the leach solution and consume carbonate reagent; and 3) substantial increase in extraction of vanadium, which is usually low when the un-roasted ore is leached. Recovery of vanadium may be an important factor in processing carnotite ores, and the fact that vanadium is usually recovered in good yield by acid leaching has often been an economic advantage over results obtained with carbonate leaching. It has been found that response of an ore to carbonate leaching, following roasting, depends primarily on its composition and on the conditions of the prior roast treatment, particularly with regard to the roasting temperature, the atmosphere maintained above the charge during roasting and cooling, and the presence of certain reagents. These factors, especially the last, virtually determine the extractions of uranium and vanadium attainable by carbonate leaching, as well as the reagent consumption on leaching, whereas adjustment of the leaching conditions has only a limited influence. These variables were examined systematically to elucidate roasting and carbonate leaching of carnotite ores and to establish a treatment yielding high recoveries of both uranium and vanadium. Tests were conducted on samples of four different Colorado Plateau ores, described in Table I. Roasting Procedure: The roasting tests were conducted in an electrically heated furnace in which the temperature was controlled to ±15°C. The ore (usually a 500-g charge) was ground to —100 mesh, mixed with the desired reagent, and spread in a silica tray to a bed depth of about 1/2 in. During the roast the charge was rabbled at intervals of 15 min. To provide free access of air the furnace was usually ventilated; however, in a few experiments a controlled atmosphere such as carbon dioxide or hydrogen was maintained above the charge. Leaching Procedure: The pulp, generally comprising 500 g of ore and a 2000-cc solution containing 80 g per liter of Na2CO8 and 20 g per liter of NaHCO3, was agitated in an autoclave at 120°C, under 30 psi 02. Samples were withdrawn periodically, and the solution and ore residue were analyzed. Under the conditions employed, maximum attainable extractions were generally achieved in 4

Jan 1, 1959

By Robert W. Hunt

In 1888 the writer had the honor of submitting to the Institute a paper on " Steel Rails and Specifications for their Manufacture."* In his judgment the specifications were sufficient for "that day and generation." In that paper I said: '' The first duty falls upon the railroad engineer in designing his section. If that is bad, the steel-maker will be heavily handicapped in trying to furnish a satisfactory rail. I suppose it is hopeless to expect the adoption of standard sections."

Jan 1, 1896

By J. W. Wolfe

The Benedict-Webb-Rmbin equation of state was used in digital computer programs to make rapid determinations of natural gas equilibrium phase compositions. Mixture components were the nine hydrocarbons, methane through heptane. Comparative tests were made with data from field separators, plant exchangers and literature sources. For most tests made, the B-W-R equations predrcted component K-vallles, mixture enthalpies and phase aensities within tile accuracy of available correlations for rune-component mixtures: significant deviations were noted when mixtures contained components heavier than heptune. INTRODUCTION Rapid, accurate methods for calculating the properties of hydrocarbon mixtures are needed for predicting the behavior of natural gas processes. For example, because of the common use of two-phase separation methods in gas proccssing, calculations must be made for the density and composition of equilibrium vapor and liquid phases. In addition, predictions must often be made for the temperature and pressure changes associated with the flow of single- and two-phase natural gas fluids through heat exchangers, chokes and turbines. The complex nature of non-ideal mixtures makes rigorous calculations for these natural gas properties difficult and time-consuming. Natural gas properties have conventionally been determined with generalized data correlations. These correlations, such as the K-values presented in the NGAA Equilibrium Ratio Data Book, are usually based on some average property of the mixture and have proven to give satisfactory estimates for the properties of most oil and gas systems. Digital computers, however, have not only increased the utility of these correlations, but also have made practical the use of equations of state for calculating the properties of natural gases. Potentially, if basic pure component data are available, all the desired thermodynamic properties of mixtures can be derived from a single equation of state describing the mixture. Currently. the best equation of state for describing the behavior of pure, light hydrocarbons over single-and two-phase regions, both below and above critical pressure, is that of Benedict. Webb and Rubin.' The equation contains eight constants which are determined by empirically fitting the equation to pure-component PVT data. Benedict and his co-workers presented the clevelopment of their equation as early as 1940.2 The B-W-R equation is a modification of the Beattie-Bridgeman equation of state and gives better PVT predictions than the Beattie equation at densities above the critical density. Benedict et al. made the equation applicable to mixtures by relating the mixture constants to composition and the constants for pure compounds. These authors, in a serics of articles in 1951,' showed the accuracy of the B-W-R equation when applied to light hydrocarbons and their simple mixtures, and demonstrated the equation's utility for making vapor-liquid equilibria calculations. Since its inception, the B-W-R equation has been the subject of many papers. Numerous additions and modifications have been proposed,'-',"'-':' the purpose of most being to improve the equation's ability to predict PVT properties of specific mixture systems. In 1959, Opfell, Pings and Sage summarized much of the work on the B-W-R equation in their book on equations of state." Since natural gases are primarily mixtures of light hydrocarbons, the B-W-R equation is a natural choice for an equation of state to compute both phase equilibria and thermodynamic properties of natural gases. Consequent-

Jan 1, 1967

By John Birkinbine

For two pears past the Warwick Furnace, at Pottstown, Pa., has attracted attention by the remarkable work done in it, and a statement giving details of its operation and the unexpectedly short biast of 1880 will be acceptable to every member who studies blastfurnace practice. There are so many interesting features in connection with this blast, and so touch to be learned from investigating it, that the results of ' thorough examination are offered to the Institute sans theories. In collecting the information, the courtesy of the various officers of the Warwick Iron Company was of material advantage, every facility for investigation being extended and an inspection of records being kindly permitted. In the following description these authoritative data are given in full where practicable, without making the paper too prolix, and the

Jan 1, 1881

By R. W. Gurry

IN the course of a series of measurements of the rate of diffusion of carbon in austenite at about 960°C. (1760°F.) and 1110°C. (2030°F.), it became necessary to determine carbon concentration when austenite is saturated with graphite, because of indications that the hitherto accepted value of the solubility of graphite in this temperature range is too low. Specimens of carbonyl iron were saturated at temperature in a hydrogen-toluene atmosphere which was in equilibrium with graphite. The carbon content of the steel was measured either by combustion or by the loss of weight after substantially complete decarburization in an atmosphere of hydrogen saturated at room temperature with water vapor. The absence of carbide or graphite as a phase at temperature was demonstrated by microscopic examination of saturated specimens that had been drastically quenched. The mean result of concordant measurements is that gamma iron saturated with respect to graphite contains 1.39 per cent carbon at 957°C. (1755°F.) and 1.89 per cent at 1110°C. (2030°F.). These two values, plotted along with what appears from the literature to be the best value (0.69 per cent) at the iron-graphite eutectoid temperature (738°C. or 1360°F.), yield a curve that is almost linear, and which, continued upward through a short interval, leads to a limiting solubility of 1.98 per cent at the iron-graphite eutectic temperature 1135°C. (2075°F.) instead of the commonly accepted value of about 1.7 per cent. EXPERIMENTAL PROCEDURE The samples of carbonyl iron, with the exception of those for microscopic examination, were cylinders 3.8 cm. long, 0.475 cm. in diameter. They were placed in a graphite holder and suspended in a vertical furnace, the temperature of which was controlled precisely by means of the resistance of the platinum winding.1 In the empty furnace the range of temperature over a distance of 4 cm. at the heat center was 9°C. (16°F.) but at a given location the temperature remained within ±0.5°C. (0.9°F.); it was measured by inserting a platinum-rhodium couple calibrated at the melting point of palladium, 1555°C. Since the presence of the sample probably improved the uniformity of temperature, it was decided to consider the average temperature of the sample to be 3°C. lower than the maximum measured in the empty furnace with the same setting of the controller. Data were obtained in the vicinity of two temperatures, 960°C. (1760°F.) and 1110°C. (2030°F.). The samples for microscopic examination, 2.2 cm. long, 0.475 cm. in diameter, were suspended individually on pure iron wire; for these no temperature correction was applied. The carburizing gas passed into the furnace was dry, oxygen-free hydrogen saturated at room temperature with

Jan 1, 1942

By E. P. Bucklen, L. J. Prelaz, J. R. Lucas

Today, the future of the coal industry is extremely bright because coal can be produced at a cost which makes it competitive with other energy sources. However, the industry has been forewarned that further cost reductions must be made if it expects to remain a serious contender in the growing energy market. Surface as well as underground operations must be improved. The very same elements which affected production a few years ago still exist today and will continue to be present in the future. Improvements in production mining equipment, mining methods and auxiliary equipment have resulted in reduced costs over the past few years. Efforts must be continued toward further reducing costs in areas which have been previously improved and new areas should be investigated for possible improvements. Therefore, new techniques must be developed which will enable the industry to augment its current efforts in reducing the cost of mining. The logical place to begin evaluating the factors affecting production and cost is in the immediate face area where a substantial part of the total cost of mining is incurred. The coal industry stands to gain much through the development of new techniques for analyzing the numerous variables affecting production and by establishing methods for eliminating or minimizing the adverse effect of those variables which can be controlled. Intuition and trial-and-error methods have been the standard means used to resolve many of the factors which influence production. As a result, many elements are overlooked or ignored because their effects on production are not pronounced and cannot be readily resolved.

Jan 3, 1965

By Robert E. Wilson, J. K. Roberts

IN order to make clear the reasons for the basic importance of petroleum and natural gas in the world today, and the problems faced by our scientists and technologists in using efficiently these great natural resources and finding possible replacements for them, it will be necessary to present a brief discussion of hydrocarbon chemistry The most important use of petroleum products is as fuel, particularly for the various forms of the internal-combustion engine There are, of course, hundreds of thousands of chemical compounds that give off heat when they burn, that is, when they combine with the oxygen of the air If a capable chemist were assigned the problem of finding the ideal volatile liquid fuel for use in an engine, he would probably begin by referring to the tables that give the heats of combustion of the chemical elements Of all the ninety-odd elements, hydrogen shows up with by far the highest heat of combustion-about 52,000 British thermal units per pound Unfortunately, however, hydrogen is a very light gas, which can be liquefied only at very low temperatures To burn it as fuel in an automobile would require a balloon about as big as the car to hold the equivalent of a gallon of gasoline, or, the hydrogen could be compressed in heavy steel cylinders, but -this would require about 125 pounds of steel per pound of hydrogen. Obviously, then, hydrogen itself cannot be considered

Jan 1, 1947

By Knapp. Arthur

THE ORDINARY well log is subjected to a great deal of criticism, much of which is well founded. Sometimes, though, the difficulty in interpreting the log is due to the fact that the geologist or engineer using the logs does not know the limitations of the drilling method used. The rotary drill, especially, has inherent limitations that make it difficult, to secure .definite information at all times. The identification of well-defined key beds is about all that can be expected from the rotary log. The formation in a drilled hole, as reported by the driller; has a direct relation to the speed with which the drill makes the hole or to the reaction of the various strata on the bit, called the "feel of the bit." When this is not thoroughly understood by the geologist or engineer endeavoring to interpret the log, the result is an erroneous correlation with other wells or a discarding of the log as worthless. GENERAL TERMS Hard and Soft.-Hard and soft are relative terms. In the case of well logs, they are very misleading as they are used in connection with both resistance to abrasion and resistance to percussion. In technical rock classification, hardness is relative resistance to abrasion. The term brittleness is used in connection with resistance to blows. These terms are misleading to the geologist or engineer who is not familiar with both the cable-tool, or standard tool, method of drilling and the rotary method. In the case of the standard tools, the driller's report of the hardness of the formation is in terms of its resistance to blows. For instance, a cable-tool driller might be able to make from 30 to 50 ft. a tour in a brittle limestone, which he would call soft and at the same time he might call a relatively soft (from a purely mineralogical standpoint) gypsum hard, because it is somewhat elastic and is not readily broken by blows. The rotary driller would reverse the terms. The limestone is hard in that it resists the abrasive action of the bit, while the gypsum might be soft in that it is readily cut by the rotary bit. It is rare that wells drilled by the

Jan 2, 1920

By AIME AIME

THE fifth annual fall meeting of the Petroleum Division of the A. 1. M. E. went down into history as being one of the best ever held by this Division and marked progress was made in the concentration of sentiment regarding several matters-particularly the principles of unit control or operation of oil pools. The first day's program was devoted to the discussion of well spacing and many valuable data were assembled and presented and the discussions following the reading of the different papers was interesting and spirited. However, throughout the whole trend of the discussion it was noted that in the background there was the idea of unit control of the pool and if such a condition could be secured the well spacing theories could be applied much better than could be hoped for if each lease in the pool was treated as a separate and individual unit.

Jan 1, 1929

By S. W. Poole, J. A. Rosa

The object of this investigation was to determine the distribution of chemical elements within a large, killed alloy-steel ingot, by sulphur printing and quantitative chemical analysis. With regard to segregation in steel ingots, the factors of melting practice, pouring temperatures, mold design, etc., and the mechanics of solidification and its attendant functions, have been the subject of intensive study over a period of years by many investigators. Notable among these is the Sub-committee of the No. 5 Committee of the British Iron and Steel Institute. For an exposition of the many problems awaiting the researcher on the heterogeneity of steel ingots, the methods of attacking these problems, together with some of the answers, the reader is referred to the nine reports and numerous papers of that committee and its membership. Steelmaking Data Melt.—The heat was made in a 70-ton direct arc-type basic electric furnace. Furnace charge consisted of nickel-chromium-molybdenum steel, most of it in the form of heavy mill scrap. All of the scrap was charged cold. The standard double-slag method was employed, the heat being finished under a strong carbide slag. Aluminum was used as the deoxidizing agent. Tapping tempera- ture, as observed with an optical pyrometer, was 3000°F. Detail of Mold and Ingot Size.—Details of the ingot mold and the ingot itself are given in Fig. I. Teeming.—Teeming temperature of the subject ingot as observed with an optical pyrometer was 2830°F. The ingot was top-poured directly through a 1 1/2-in. nozzle and required 7 min., 44 sec. to fill up to the hot top. An additional 2 min., 30 sec. were required to fill the hot top. The ingot was stripped hot and charged with the remainder of the heat into an annealing furnace. There it was given the standard annealing cycle used for these ingots. Subsequent heat-treatments are described elsewhere in this paper. Sectioning and Preparation for Sulphur Printing Because of previous favorable experience in sectioning ingots up to 21 1/2 in. square with an oxyacetylene torch, it was decided to use this method to section the subject ingot. The ingot was preheated to 900°F. for 12 hr. It was then placed on a steel bed in a horizontal position so that the longitudinal axis was level and parallel to the track of the motor-driven torch carrier. Two cuts were made, one 2 in. above the longitudinal axis and the other 2 in. below. The time required to make each cut was approximately 75 min. The cutting operation is shown in Figs. 2 and 3. The 4-in. thick slab was mmediately charged into a furnace standing at 1200F.

Jan 1, 1945

By S. W. Poole, J. A. Rosa

THE object of this investigation was to determine the distribution of chemical elements within a large, killed alloy-steel ingot, by sulphur printing and quantitative chemical analysis. With regard to segregation in steel ingots, the factors of melting practice, pouring temperatures, mold design, etc., and the mechanics of solidification and its attendant functions, have been the subject of intensive study over a period of years by many investigators. Notable among these is the Sub-Committee of the No. 5 Committee of the British Iron and Steel Institute. For an exposition 0f the many problems awaiting the researcher on the heterogeneity of steel ingots, the methods of attacking these problems, together with some of the answers, the reader is referred to the nine reports and numerous papers of that committee and its membership. STEELMAKING DATA Melt.-The heat was made in a 70-ton direct arc-type basic electric furnace. Furnace charge consisted of nickel-chromium-molybdenum steel, most of it in the form of heavy mill scrap. All of the scrap was charged cold. The standard double-slag method was employed, the heat being finished under a strong carbide slag. Aluminum was used as the deoxidizing agent. Tapping temperature, as observed with an optical pyrometer, was 3000°F. Detail of Mold and Ingot Size.-Details of the ingot mold and the ingot itself are given in Fig. I. Teeming.-Teeming temperature of the subject ingot as observed with an optical pyrometer was 2830°F. The ingot was top-poured directly through a 1 ½ in. nozzle and required 7 min., 44 sec. to fill up to the hot top. An additional 2 min., 30 sec. were required to fill the hot top. The ingot was stripped hot and charged with the remainder of the heat into an annealing furnace. There it was given the standard annealing cycle used for these ingots. Subsequent heat-treatments are described elsewhere in this paper. SECTIONING AND PREPARATION FOR SULPHUR PRINTING Because of previous favorable experience in sectioning ingots up to 21 ½ in. square with an oxyacetylene torch, it was decided to use this method to section the subject ingot. The ingot was preheated to 900°F. for 12 hr. It was then placed on a steel bed in a horizontal position so that the longitudinal axis was level and parallel to the track of the motor-driven torch carrier. Two cuts were made, one 2 in. above the longitudinal axis and the other 2 in. below. The time required to make each cut was approximately 75 min. The cutting operation is shown in Figs. z and 3. The 4-in. thick slab was mmediately charged into a furnace standing at 1200°F.

Jan 1, 1944

By C. Augustus Carlow

THE subject which has been allotted to me is so vast and far-reaching that it is impossible to deal adequately with it in the time available. A complete survey would occupy the spare time of any one man for many years, whereas the time available to me is measured in weeks In the circumstances, I have been fortunate in securing the aid of several willing collaborators, and shall endeavor to re present such information as presently exists in published form, examine the situation critically in the light of present-day conditions, and arrive at certain conclusions' which I shall venture to put forward for your consideration No one who has lived through the past 25 or 30 years, and who has witnessed the amazing achievements of recent scientific research, would venture to deny the possibility that new sources of energy-may yet become available, or to prophesy to what extent these may be harnessed to the service of mankind So far as we can see, however, coal, as a source not only of power and heat but also of that wonderful range of derivatives that form the raw materials of so many industrial processes, must continue to play a vital role in our economic life It is the chief mineral fuel, exceeding all other mineral resources in value, production and demand In value coal overshadows the industrial metals, while of the sources of energy-coal, oil, gas and water power-the first named is the most important Thus, for example, in the United States, coal as a fuel (that is, as a source of heat and power) is still predominant, the figures of percentage of

Jan 1, 1947

By William Campbell

(Cleveland Meeting, October, 1912.) [SECRETARY'S NOTE.-To avoid repetitions of foot-notes, references to authorities are made in the paper by means of figures, referring to a numbered list in the appendix.-J. S.] I. INTRODUCTION. IN the olden days the making of alloys was au art, and the secrets of the craft were jealously guarded. To-day it has become a science, though the old ideas in regard to the secrets and formula are dying hard. Modern progress may be attributed to scientific research and testing of materials, and the substitution of chemical analytical control for " cook-book " methods. We know to-day a great deal about the constitution of alloys, the reasons of the change in structure and physical properties by heat and mechanical treatment; and this new knowledge is due for the most part to the physical chemist and metallographist, who have shown us that alloys are simply solutions, and as such obey definite laws. The application of the theories of solutions and of the phase rule tells us what ought to happen when our alloys are in a state of equilibrium. The working-out of the temperature-composition diagram (thermal diagram) for numerous alloys has thrown a light on the structure and constitution which has dispelled most of the darkness in which we labored before the advent of metallography. The work began with the determination of the freezing-point curves, and here the research of Le Chatelier,1 Gautier,2 Roberts-Austen,3 and the other pioneers broke the ground. Next the physical chemists, Tammann,4 Rooseboom,5 Bancroft,6 and their colleagues, showed us the complete thermal diagram and its meaning. Then the researches of Heycock and Neville 7 on the Cu-Sn series and of Shepherd 8 on the * Associate Professor of Metallurgy, Columbia University in the City of New York.

Dec 1, 1912

By Pedro G. Salom

I HAVE had an opportonity, within the last few months, of making a large number of physical and chemical tests of steel for boiler and ship-plate, which has been, and is now being, used principally for the United States Government cruisers, now building in Mr. John Roach's yard, at Chester, Pa. Through the courtesy of the Messrs. Houston, of the Chester Rolling Mills, I have the honor to lay before the members of the Institate the results of these tests. These results have developed some points in regard to the nature of steel, which are more or less new, and which, I hope, will prove interesting. The original specifications, as regards the manner of testing, were so inipracticable (when their severity mas taken into consideration), that the keel of the first vessel, which will be launched next month, would, had they been carried out, probably not have been laid until next year. At my suggestion, in order to simplify and expedite the immense amount of testing that had to be done, the Naval Advisory Board was induced, after considerable discussion, to alter the specifications, so as to test each heat, instead of each lot of twenty plates, but reserved the right of making the quenching-test on a piece from each ingot, after it had been rolled. This relieved us from the anxiety of having a lot of plates rejected, after they had beell rolled and sheared, by reason of the presence of one or two plates which might have been injured in heating or rolling, or which might not have been able to stand the tests; while it insured the Government in obtaining a uniform quality of steel, and prevented the temptation to introduce a half-dozen or more had plates in a lot, and run the risk of their being selected as the testplates. I give below a portion of the original specifications, as prescribed

Jan 1, 1884