Search Documents

The Library of the above-named Societies is open from 9 A.M. to 10 P.M., except on holidays. It contains about 70,000 volumes and 90,000 pamphlets, including sets of technical periodicals and publications of scientific and technical societies. Members of the Institute, with few exceptions, are forced to spend a portion of their time in localities isolated from sources of information. To these the Library, through its Library Service Bureau, can render valuable service through correspondence; letters requesting information will receive especial attention. The Library is prepared to furnish references and photographic copies of articles on mining and metallurgical subjects; to determine the existence of mining maps, and to furnish general information on the geology and mineral resources of all countries. All communications should be made as definite as possible so that the information received may be what is desired and not include collateral matter which may not be of interest. The time spent in searching for such collateral matter will be saved, and the information will be sent more promptly and in more usable shape.

Jan 12, 1917

By R. H. Card

THE geophysicist is interested greatly in the resistivities of different formations or parts of the earth's crust; sometimes he is interested in a single figure in the nature of an average, or what may be called the effec-tive resistivity, of all the formations or parts of the crust at a given location to a certain depth. Conversely, the engineer whose work is concerned with the coordination of power and communication lines in such a manner as to avoid electrical interference between these two types of facilities is concerned very much with this effective resistivity; to a lesser extent he is interested in the resistivities of individual forma-tions. In connection with his work the coordination engineer often estimates the effective resistivity; of the earth from measurements of the mutual impedances of lines; in other instances he derives front measure-ments of a different type the resistivities of different layers of the crust and synthesizes these to obtain an estimate of the effective resistivity. In connection with problems concerning the coordination of power and telephone lines, measurements from which earth resistivities can be estimated have been made at many points in the United States by the American Telephone and Telegraph Co. and its associated companies, in cooperation with various power companies and with railroad companies having electrified sections of line. Other such measurements have been made by the Joint Subcommittee on Development and Research of the Edison Electric Institute and the Bell Telephone System. A study has been made of the correlation of these data with the ages and types of materials of the strata of the earth's crust at each of the test locations. The purpose of this study has been primarily to provide information to assist in predicting the order of magnitude of effective resistivities to be used in the preliminary consideration of problems con-cerned with the coordination of power and communication lines. To make the results of such a study, most useful, it is essential that the geo-logical data to be secured when such a prediction is wanted be readily obtainable. Data on the ages of strata and the types of materials com-posing geological structures can usually be obtained, therefore particu-

Jan 1, 1937

By Renato G. Bautista, Robert A. Hard

A comparative study has been made of the ex-tractability of several of the transitim metals from thiocyanate sohtions using methyl isobutyl ketone as the organic solvent. Extractions were made of scandium (III), chromium (III), manganese (II), iron (III), and cobalt (II), of which only the scandium , iron, and cobalt were readily extracted. All extractions were made at pH 2 and at 25.5 °C. A series of extraction experiments was made on scandium, iron, and cobalt to determine the effect of thiocyanate cmcentration added as the ammonium and also as the calcium salt. Also determined was the effect of metal ion concentratim and ionic strength on the distribution ratio. Analyses of the organic extracts indicated the scandium and iron were extracted principally in the uncharged trithiocyanate form, while the extractable form of the cobalt contained the cobaltotetrathiocyanate anion. THE chemical separation of metal complexes in solution by solvent extraction has in recent years been developed for large scale separation as well as bench scale work in the laboratory. It has also found increased application in analytical chemistry. Its extension to extractive metallurgy as a unit operation is best illustrated in the recovery of uranium and vanadium from their leached liquor.5-8 The extractability of some thiocyanate systems have been extensively investigated. The rate earths have been separated from one another using butanol as a olvent. Scandium was effectively extracted in ethyl ether using ammonium thiocyanate as the com-plexing agent.'' Similarly, the separation of hafnium from zirconium has been reported using ether""' or hexone13 as the organic solvent. The extractability of various metal thiocyanates in ethyl ether is given by 0ck.l Sharp and Wilkinson15 prepared nickel-free cobalt slats by thiocyanate extraction. The mechanism of extraction of titanium (IV) thiocyanate with methyl isobutyl ketone was determined by elafosse.''" The characterization of cobalt (TI) thiocyanate complex using methyl isobutyl ketone as the solvent at near neutral aqueous solution and the spectrometric studies of the ex-tractable cobalt complex has been made by Hard." It is noteworthy to mention at this point that the fundamental characteristic of ketone (oxonium) solvent extraction is that the extractable species are uncharged ion pairs solvated by the ketone molecules, but probably still partially hydrated.

Jan 1, 1963

By L. C. Uren

Field studies and laboratory research have established the fact that the expulsive force which drives petroleum into wells, from the reservoir sands in which it is stored by nature, is primarly an expression of the energy latent within compressed natural gas dissolved or occluded in, or otherwise associated with the oil. Each barrel of oil produced is forced into the recovery well by the expansive energy of a certain volume of compressed gas, originally stored with the oil in the pores of the reservoir rock; and each cubic foot of gas so produced with the oil and expanded to atmospheric pressure reduces by so much the total natural energy available for oil expulsion. This relationship between the volumes of gas and oil produced has seemed so important that petroleum production technolo-gists have come to regard the "gas-oil ratio," or the "gas factor" as it has been more conveniently termed, as a measure of oil-production efficiency. Different methods of oil recovery and production devices are now Com pared on this basis and estimates of ultimate recovery obtainable through their use are considered by many to be inversely proportional to the values of their respective gas factors. The writer has been among those who have given support to a widcspread movement toward a proper recognition of the significance of the gas factor as a guide in the control of producing oil wells, and does not wish to oppose its more extended application. It seems necessary, how-cvcr, in view of the almost elemental faith with which the principle of the gas factor has been received in many quarters, to point out that it is a most complex factor, and one which cannot be regarded as an absolute index of production efficiency without due regard to other contributing factors by which it is influenced to an important degree. Variables Influencing Gas Factor The mere recording of a low gas factor, obtained through the use of some method or device, does not necessarily imply efficient oil production; and conversely, a high gas factor does not always signify inefficient recov-

Jan 1, 1928

By N. M. Parikh, T. J. Koppenaal

The strengthening mechanism of fiber-reinforced silver has been investigated as a function of fiber density and fiber material. Stress-strain curves were determined in the range 2 x 10-6 to 2 x 10-3 plastic styain and slip lines were examined. The yield strength at 0.2 pct permanent strain is markedly dependent upon fiber density but the stress necessary to initiate plastic deformation is independent of fiber density. The strengthening mechanism of the fibers is shown to be malogous to grain boundary strengthening in poly crystalline metals. The variation in strengthening with different types of fibers is also noted and discussed. In recent years, considerable progress has been made in the understanding of the mechanical properties of two-phase systems, particularly in the classical dispersed-phase alloys where the separation between the dispersed phases is 0.01-0.1µ. However, little work has been done on fiber-reinforced metals where the dispersed-phase separation is considerably larger than this. Parikh1 investigated the mechanical properties of many fiber-reinforced metals and found that two general relationships are always observed, as follows: 1) A fibrous network incorporated into a second weaker metal strengthens the latter, and the amount of strengthening increases with fiber concentration. 2) At a corrstant fiber concentration, the amount of strengthening in a given matrix can vary considerably, depending upon the type of fiber employed. The object of the present investigation was to examine the fuiidamental factors controlling these two observations. procedure: Fig. 1 shows the initial step in the fabrication of the specimens. The sieve is shaken so that the fibers fall into a mold with the longitudinal axes of most fibers in the X-Z plane. The fibers are then compressed to a predetermined density, thus forming a "felt", and the necessary amount of matrix metal is added to the top of the felt. The mold is heated, in vacuum or hydrogen, to above the melting point of the matrix metal; the molten metal flows into the felt, and the entire assembly is cooled. This produces a "composite" that is essentially free of voids. A number of composites were prepared in this manner using 1/4-in. kinked lengths of mild steel

Jan 1, 1962

By John R. Edwards

Introductory.—There are many interesting and important events connected with the petroleum problem. The remarkable men who conceived 'the thought of transporting petroleum by pipe line, conserving the byproducts of the commodity, and conducting extended investigation and research whereby the flash point of the oil was raised, its cost reduced and its supply assured, are deserving of the gratitude of this nation. It was primarily the success attained by Captain Lucas, after his comprehensive search for oil in Texas and Louisiana, that was the impelling cause which prompted the Navy Department to conduct the extensive series of liquid fuel-oil tests that were made from 1901 to 1903. The sensational discovery of oil at Spindle top made a deep impression upon Rear Admiral George W. Melville, then Engineer-in-Chief of the Navy, and the discovery of the vast oil field in Texas convinced him that, within a generation, if not within a decade, crude petroleum was going to play a very important part in warfare, and that the commodity might possibly develop into a necessary munition of war. The United States' Commanding Position as a Petroleum Producer.— In the study of the various problems relating to the world's production of crude petroleum, the position of the United States is one of commanding importance, whether viewed from the industrial or the military aspect. The present yield of this country is practically double that of the rest of the world, and, in view of the productive and prospective fields possessed by various countries, together with the comprehensive and exhaustive search that has been made throughout the world for petroleum, it is extremely probable that this lead will be maintained for the next decade. As regards the character of the crude-oil yield of different countries, America possesses the greater part of the supply that contains a paraffine base, and therefore a considerable portion at least of the American product produces the best illuminant. Of all the crude-oil distillates, kerosene is in many respects thc most important, and the Appalachian product for this purpose is favored, particularly in the Far East, above that of any other petroleum yield of the world.

Jan 1, 1915

By P. F. McIntyre

Electrolytic refining of lead was first carried out on a commercial scale at Trail, B. C., in 1903. The capacity at that time was small, and cell-changing operations were managed with chain block and monorail. Development up to 1922, utilizing crane installations and cell additions, attained a production of 100 tons per day. Successive additions from 1922 to 1926 further increased the rated capacity to 396 tons per day. Other improvements in metallurgical practice have gradually increased production, until for the year 1935 it was 448 tons per day. During the first five months of 1936, an average daily production of 504 tons was maintained without increasing the size of the plant. Lead Refinery Buildings.—The tank room and the lead-melting and casting equipment are housed in two buildings, which parallel each other and which for the greater part of their lengths are joined by a connecting aisle. All basements, walls, sumps and floors are of concrete. Where exposed to the electrolyte, the concrete has a protective coating of asphalt (220" melting point) over a coat of asphalt paint as a primer. Buildings erected before 1924 are of wood. More recent additions are made of structural steel with gunite siding. A brick building, adjoining the older section of the tank room, houses the slimes-treatment plant. The power house, containing motor generators, air compressors and rectifiers, is constructed of tile. Cell Construction.—The electrolytic cells are of reinforced concrete lined with asphalt. They are cast in pairs, the outside dimensions of a double cell being 113 in. long by 73 in. wide by 48 in. deep. The bottom is 6 in. thick and the sides, ends and center wall are 4 in. thick. A ledge 3 in. wide and 2½ in. deep is left along the top of the side walls to carry the insulators and bus bars. Reinforcing consists of ½-in. round iron rods. Cell inspection and repair work is done in conjunction with the cell-changing operations. The repair work necessary is usually confined to renewing chipped asphalt, unless a tank has been accidentally broken. Minor concrete repairs can be easily made in place. The broken concrete

Jan 1, 1937

By AIME AIME

OUR own Institute of Metals and Iron and Steel divisions cooperated with the Iron and Steel Division of the American Society of Mechanical Engineers, the American Welding Society, and the American Society for Steel Treating in a busy week at Cleveland. The morning sessions were held at the Hotel Cleveland and the afternoon ones at the Auditorium, where the metallurgical exhibition under the auspices of the American Society for Steel Treating not only occupied the arena of the Auditorium but completely filled the huge adjacent Annex. In the intervals of sessions the members thronged the exhibits but in the evenings the local attendance was so great that if the crowds had been any larger it would have been difficult to see the exhibits. With so many firms, both producers of metals and of equipment accessory to their production and use, it would be impossible to mention them -all and unfair to single out a few, since no two individuals' judgment would coincide as to relative interest and importance. In any case an exhibit is a thing to be seen rather than described, and these were well worth seeing.

Jan 1, 1929

By C. R. Breck

THERE has been a running discussion over the past several years with respect to the life and adequacy of our natural gas reserves. Some of the experts agree on one phase of the subject at least-that eventually it will be necessary to augment deliveries of natural gas in the northern markets by the development of a more or less comparable synthetic gas made from coal. The purpose of this paper is to point out: 1. It may be later than a good many people think-the demand for addi¬tional domestic and commercial pipeline gas in at least one section of the North will probably be felt rather keenly before an adequate synthetic pipe¬line-gas project, developed on economic lines, could be completed, even if initiated in the near future. 2. The evidence is considerable that such a project would be technically sound and economically self-supporting, although the margin of profit at first might be so small and the magnitude of an economic enterprise so great -that financing would be impossible without Government aid in some form or other. The part of the country referred to is the heavily populated section in the northeast of the United States. To simplify an examination of the situa¬tion, let us take the potential marketing areas within range to the north and east of the three pipelines: 1. Tennessee Gas Transmission Co. as it enters Erie County, New York state. 2. Texas Eastern Transmission Corporation just before the tap that sup¬plies the general Philadelphia area. 3. Transcontinental Gas Pipe Line Corporation as it enters the state of New Jersey. The sources of gas for these three pipelines are in Texas and Louisiana. The ultimate maximum combined capacity of the three lines at the points stated is approximately 1,200,000,000 cu ft per 24 hr at the maximum load factor probable of attainment in normal operation. The areas supplied by the three lines north and east of the points stated, or assumed as eventual markets, are: 1. Central New York state, from Buffalo to Albany (both inclusive).

Jan 1, 1953

THE distinction btween price reduction as a re-sult of lowering of production cost and price re-duction through unrestricted competition cannot be made too clear, because they are often interwoven in actual experience. Take the whole population of a town whose principal industry is shoe manufacturing as a concrete example. If the manufacturer is able to cut his price per pair in half because he has found out how to make a pair at half the cost, he will com-monly let a number of his men go, because reduction in production cost usually results from substituting cheap mechanical energy for expensive human energy. These people will normally find other employment. The workmen who remain employed usually earn more in dollars than they did before, and in spending it give employment where there was less before. Mining companies that initiate considerable enter-prises in foreign lands where the economic level is low, and where most of the people are busily but in-efficiently engaged in raising enough food to support themselves and their families, often find themselves confronted with an acute labor problem. If any con-siderable number of workers leave the land to work in and about the mines, those left on the land cannot raise enough food to keep them all unless they are taught better methods of agriculture and provided with equipment that will enable them to produce more with less expenditure of effort. Add to this the fact that managers commonly find that the "natives," as our British cousins designate them, usually need more food and a better balanced diet than they have been accustomed to in order to show anything above the lowest order of efficiency in industrial work,. and it is clear that to make a new industry possible in what may be termed an economic province involves increas-ing the productivity, not only of those who are em-ployed in it, but of the whole social group. It has already been pointed out that the employ-ment of large numbers of men in automobile manu-facture is only possible because the others have in-creased their productivity enough to turn out every-thing else that is needed without the help of the auto-mobile workers.

Jan 7, 1928

By H. C. Jennison

Two distinct types of defects occur at times in copper wire as a result of the use of dies of improper design or undesirable wire-drawing practice. The conditions under which these defects may be produced, as well as precautions to be taken in order to prevent them, have been known to The American Brass Co. for many years. The quality of the copper wire bars and rods has too often and unjustly been held responsible for these particular defects and it is to correct any such belief that this paper is presented. An extremely high quality of electrolytic copper has been supplied to the trade by all refineries for the last 20 years at least. The purity of the copper would average well above 99.900 per cent. The casting of the wire bars has been handled in a generally satisfactory manner. The bars have been cast sound, with a flat to slightly crowning set and have been free from sloppy edges, cold sets, etc. In other words, the wire bars have met A. S. T. M. specifications and have been generally satisfactory. For the most part, they have been everything that could be desired from a quality standpoint yet most of the wire mills in this country and in Europe have at times held the quality of the copper responsible for the two types of defects described in this paper. As a matter of fact, these defects are produced entirely in the wire mills. The author has visited many of the large wire mills in the United States and in Europe to investigate these defects. In some cases the trouble has been so serious that the wire mill has ceased operations. At times the wire mills are reluctant to believe that they are responsible for the defective product. The effect of die design, wire-drawing practice, etc., upon the quality of copper wire has received' little study on the part of wire mills, particularly those that have commenced operations in the last few years.

Jan 1, 1930

By J. E. Johnson

(Cleveland Meeting, October, 11,1912.) THE subject of blast-furnace slag is one which has had much consideration, particularly from the scientific standpoint, and several years ago technical literature contained many learned discussions on the oxygen-ratio of the acids and the bases, all on the assumption that acids and bases must be present in a ratio depending on molecular weight and chemical valency. Much work has also been done, sometimes in conjunction with the former, on the total heat and the temperature of initial fusion or softening of various slags. A wider knowledge of the blast-furnace now enables us to say that for practical purposes this work has been of almost no value. It is now generally admitted that on the physical side the important point of a given slag is neither its total heat of fusion nor its softening-point, but its free-running temperature, since this is the critical temperature of the furnace. This temperature bears no definite relation to the softening-temperature, as determined by Seger cones, for instance, because some slags melt relatively like ice, with a very short viscous-range, while others melt relatively like tar, with a very long viscous-range. In one the difference between the softening- and the free-running temperature may be very small, as little as 100° F., while in another this difference may easily be 200° or 300°. The importance of this difference is so great in practice as to destroy completely the value of exhaustive investigations, even such as those of 0. Boudouard, published a few years ago.1 * Presented also at the Joint Meeting of the Institute with Section IIIa, Metallurgy and Mining, of the Eighth International Congress of Applied Chemistry, New York, September, 1912. 1 It may not be amiss at this point to call attention to the excellent suggestion of Woolsey McA. Johnson, made several years ago, for determining the temperature at which different slags have the same practical fusibility. This suggestion

Oct 1, 1912

By C. Richard Tinsley

At least three major consortia are gearing up for actual mining tests in the near future, two prospective entrants are seeking partners, and significant behind-the-scene changes are occurring in attitudes at the Law of the Sea Conference. On top of this, the prospects for passage of a deep-ocean mining bill through Congress arc steadily improving, although Administration objections persist and the threat of a Ford veto remains.

Jan 4, 1976

By W. H. Bassett

Beads of metal frequently appear at the ends of cast-copper wire bars and on the sides of wedge cakes near the top. These are richer in cuprous-oxide than the rest of the casting. A micrographical study of these exudations has been made. It is suggested that the material is forced through the surface while the copper is solidifying. If not eliminated in process of manufacture, it shows on the finished polished sheet copper in patches differing in color from the main body of the sheet. FIGURES 1 to 4 show the copper exudations, at different magnifications, as they appear on the ends of cast wire bars, and on the sides, usually near the top, of wedge cakes. Sometimes the exudations are in fine "drops;" at other times, large masses of the material are found. Microscopic examination of the copper exudation indicates that it is high in oxide and of eutectic proportions. Because of the difficulty of securing a suitable sample, the protuberances have not been analyzed chemically; but the spectroscope shows no indication that there are any more metallic impurities present than in the balance of the copper. The lowest copper plus silver content of the coppers studied for this? paper was 99.914 per cent.; the highest, 99.966 per cent.; so the oxygen content of the whole casting would be well under 0.07 per cent.

Jan 2, 1926

There have been no major field developments during 1935. Operations have proceeded normally on the company's three producing fields, Masjid-i-Sulaiman, Haft Kel and Naft-i-Shah. The refinery at Kermanshah was commissioned in September, 1935, with a rated throughput capacity of 75,000 tons a year of topped crude to meet local requirements. Crude production from the Masjid-i-Sulaiman and Haft Kel fields is tabulated below: Masjid-i-Sulaiman Field.—The flowing lives of wells have been extended by (I) a process of acid treatment, thereby reducing the bottom-hole pressure differentials, and (2) by reducing the back-pressure. Optimum producing conditions for individual wells have been determined as a result of an experimental study of the amount of available energy in the reservoir crude and of energy losses in flowing wells. The return of surplus products to the reservoir has continued to be a satisfactory economic operation and the crude throughput capacity of the topping plant has been increased. The viscosity of residue returned to the reservoir is reduced before injection by regassing at 35 lb. per sq. in. absorption pressure with surplus gas. The pressure in the gas dome is falling at the low rate of one pound per annum. Haft Kel Field.—The delimitation of the main structure has proceeded; the oil-bearing area so far proved being about 50 square miles.

Jan 1, 1936

RICHARD R. HICE, Beaver, Pa. (written discussion *).-The matter of selective. mining is probably of more importance in Pennsylvania than is washing, and perhaps washing would not be necessary at some plants where now practised if proper care were taken in the mining. I have in mind one plant where the sulfur content of the entire bed is more than 2 per cent., yet if the bottom 12 in. and the top 12 or 15 in. are separated, the main portion of the bed, some 6 ft., will not contain more than 1.25 per cent. sulfur; and yet in this mine the entire bed .is worked together, the resultant coke, as a matter of course, not being fit for use in iron smelting. Not sufficient notice is taken of the "Double-thick" Upper Freeport coal in Allegheny and Butler counties. This is a very valuable deposit. Other areas where there is a, top member of the Upper Freeport coal are also known, which add to the value of this bed as a coking coal. This double Freeport coal is especially suited for byproduct coking. I cannot be as optimistic as regards the "low-sulfur" Pittsburgh coal in Greene county as the authors. If the term low-sulfur is to he confined to coal with not exceeding 1.25 per cent. sulfur, there is probably little

Jan 10, 1919

There have been no major field developments during 1935. Operations have proceeded normally on the company's three producing fields, Masjid-i-Sulaiman, Haft Kel and Naft-i-Shah. The refinery at Kermanshah was commissioned in September, 1935, with a rated throughput capacity of 75,000 tons a year of topped crude to meet local requirements. Crude production from the Masjid-i-Sulaiman and Haft Kel fields is tabulated below: Masjid-i-Sulaiman Field.—The flowing lives of wells have been extended by (I) a process of acid treatment, thereby reducing the bottom-hole pressure differentials, and (2) by reducing the back-pressure. Optimum producing conditions for individual wells have been determined as a result of an experimental study of the amount of available energy in the reservoir crude and of energy losses in flowing wells. The return of surplus products to the reservoir has continued to be a satisfactory economic operation and the crude throughput capacity of the topping plant has been increased. The viscosity of residue returned to the reservoir is reduced before injection by regassing at 35 lb. per sq. in. absorption pressure with surplus gas. The pressure in the gas dome is falling at the low rate of one pound per annum. Haft Kel Field.—The delimitation of the main structure has proceeded; the oil-bearing area so far proved being about 50 square miles.

Jan 1, 1936

By K. J. Miller, R. E. Hucko

The Coal Reparation Division of the Pittsburgh Mining Technology Center conducted an investigation to assess and compare the pyritic sulfur reduction potential of coal-pyrite flotation and high-gradient magnetic separation (HGMS). Tests were run on three coals - an Upper Freeport bed coal, a Lower Kittanning bed coal, and a Pittsburgh bed coal - to establish grade-recovery relationships characteristic of both processes. Representative portions of each coal sample were crushed to two top sizes-nominal - 500 pm (-35 mesh) and nominal - 149 pm (-100 mesh)-and subjected to conventional froth flotation. The froth product was then beneficiated by coal- pyrite flotation or HGMS, to provide a direct technical companion of the two processes. At - 500 pm (- 35 mesh), the size normally employed for coal flotation, both coal-pyrite flotation and HGMS effectively separated pyrite from coal, and the performance of the two processes was essentially the same. At a - 149 pm (- 100 mesh) sire, however, the performance of HGMS exceeded that of coal-pyrite flotation. The separation effected by HGMS were more efficient at - 149 pm (- 100 mesh) than at - 500 pm (- 35 mesh). On the other hand, it was concluded that either the effectiveness of coal-pyrite flotation decreases with diminishing top size or the process has not been optimized to treat material finer than 500 pm (35 mesh).

Jan 1, 1983

By J. Intrater, E. S. Machlin

In a study of grain boundary sliding in superpure Copper (99.999 pct),&apos; bicrystals of a specific shape were used, Fig. 1. That shape was adopted in order to minimize the deformation of grains on both sides of the boundary due to clamping. Another requirement was to obtain bicrystals with a rnicroscopically straight boundary, Fig. 2. Single crystals of predetermined orientation (growth axis parallel to <310>) were grown in a graphite mold from seed crystals. The apparatus for growing single crystals consisted of a vacuum system, argon purification train, vycor tube (in which a graphite mold was placed), a carriage for the induction coi1,and a Lepel (7-1/2 KW) high-frequency converter. The graphite mold was heated by induction and the charge in turn was heated by conduction. The induction coil was moved by means of a motor at a speed of 1 1/2 in. per hr. Single crystals of two different orientations were grown from the melt in one-half of a split graphite mold, Fig. 3(a). Two such crystals were then placed in contact with each other in another split mold, Fig. 3(b) using tapered inserts. The pair of crystals was then remelted starting 2 in. from the top to insure that the whole top portion of the crystals was maintained molten. By moving the induction coil

Jan 1, 1960

By W. J. Reagan

A SURVEY of the literature on bottom-cast practice gives but scant information as to some of the real facts concerning this most interesting method of steel manufacture, and some of the information available is very misleading.1 An exceptionally good description of this method of pouring or teeming is to be found in an English publication2 on the heterogeneity of steel ingots. Quoting from this paper: (a) With bottom teeming, the metal rises steadily and progressively in the mold with the minimum possible agitation, the main force of the stream coming from the ladle being broken down or retarded by the down gate or runner. Further, the stream of metal from the ladle, under these conditions of casting, is invariably main-tained at a much more continuous rate and is steadier than with top teeming. (b) In view of the facts referred to in (a) it follows that with bottom teeming the metal is not exposed to atmospheric oxidation to anything like the same degree as with top teeming. In this paper it is intended to detail briefly some of the advantages of bottom-cast practice and to discuss the possibilities of iron-oxide control in the basic open-hearth furnace. A description of the type of charge, ingot mold set-up, etc., is found in detail in an earlier paper.3

Jan 1, 1934