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During 1918, the activities of the United Engineering Society, the Library, the Engineering Foundation, and Engineering Council Were deeply affected by the war and much important war work Was done in our building. The endowment of Engineering Foundation was increased to $300,000 by an additional gift of $100,000 from Ambrose Swasey. By bequest of Dr. James Douglas, the American Institute of Mining Engineers received an endowment of $100,000, the income of which Will be expended in the maintenance of its library (now a part of the joint library). The Library Service Bureau has gained steadily; its business for 1918 amounted to nearly $10,000. Indexing of current engineering literature has been undertaken in conjunction With the Founder Societies and the Index is being printed in their publications. This service has been extended to the Engineering Institute of Canada and the Canadian Mining Institute. The expense is borne by the Societies. In this connection the American Society of Mechanical Engineers has purchased the Engineering Index heretofore published by "Industrial Management." In June the Westinghouse and General' Electric Co. donated to the United Engineering Society their Patent Con¬trol Library of about 8000 volumes. Other noteworthy gifts Were a collection of 370 pieces relating to patent litigations, from Jesse M. Smith, and Dr. William Paul Gerhard's collection on gas engineering, transferred by the American Gas Association.

Jan 1, 1923

The income of the Institute is derived from dues, subscriptions to MINING AND METALLURGY and sale of publications. These sources are fortunately supplemented by the interest from invested funds now amounting to over $500,000, a considerable portion constituting endowments for especial purposes. Aside from the medal funds the principal endowments are the James Douglas Fund for support of the Library, the Rocky Mountain Fund and the Seeley W. Mudd Memorial Fund. The income from the two last named is available for the support of research and a variety of other purposes. It is allocated by the Board of Directors upon recommendation of standing committees in each case. An active effort is being made to increase the endowments of the Institute, it being felt that unusual opportunities exist for research and public and professional service through the organization and at a minimum of expense.

Jan 1, 1932

By V. D. Leary, O&apos

Contracts between The Anaconda Co. and its miners at Butte, Mont., are not contracts in the true sense of the word. They are weekly verbal agreements which tacitly admit that the company, on the one hand, will supply the place, the tools, the material, and the opportunity and that the miners, on the other hand, will supply such effective labor that both parties will profit from the arrangement. Prices are seldom discussed at the time of hiring. The miner, in effect, is hired for a definite working place, as a contract miner, and if satisfied, tries to earn as much as he can. If he is not satisfied three courses are open to him: he can quit, he can ask for a change, or he can discuss prices or improved working conditions with the mine superintendent. This rather informal arrangement is due to conditions that are particular to Butte

Jan 2, 1961

By H. K. Shearer

Oil production in north Louisiana in 1938 was 28,442,910 bbl., a decrease of 225,160 bbl., or less than 1 per cent, from 1937. The principal increases were at Cotton Valley, Lisbon and Zwolle. The greatest decrease was at Rodessa, with small normal declines in production of the old settled fields. Natural gas production from gas wells declined 15.9 per cent from 1937, but casinghead gas increased, so the decline in total production was only 6.9 per cent. Decline in completions was due to lack of proven areas for drilling, as well as price and marketing difficulties; and wildcat activity mas also less than in 1937. The increase in number of dry holes was due chiefly to shallow drilling in the old Caddo and Zwolle fields. Most important events in 1938 were the discovery of the Shreveport deep oil and gas field, extension of the Logansport gas-distillate field into Louisiana, development of oil production in the Bodeaw zone on the flanks of Cotton Valley, opening of deep gas-distillate production at Shongaloo, and completion of one well in a deeper horizon at Bluc Lake (Zwolle field). Geological Notes The deep drilling done in 1938 did not cause any important changes in geological correlation and nomenclature of the formations below the Upper or Gulf Cretaceous. The stratigraphic section of the Lower Cretaceous and deeper beds, with names used in the accompanying tables, as approved a year ago by the Shreveport Geological Society, is as follows:

Jan 1, 1939

By H. K. Shearer

Oil production in north Louisiana in 1938 was 28,442,910 bbl., a decrease of 225,160 bbl., or less than 1 per cent, from 1937. The principal increases were at Cotton Valley, Lisbon and Zwolle. The greatest decrease was at Rodessa, with small normal declines in production of the old settled fields. Natural gas production from gas wells declined 15.9 per cent from 1937, but casinghead gas increased, so the decline in total production was only 6.9 per cent. Decline in completions was due to lack of proven areas for drilling, as well as price and marketing difficulties; and wildcat activity mas also less than in 1937. The increase in number of dry holes was due chiefly to shallow drilling in the old Caddo and Zwolle fields. Most important events in 1938 were the discovery of the Shreveport deep oil and gas field, extension of the Logansport gas-distillate field into Louisiana, development of oil production in the Bodeaw zone on the flanks of Cotton Valley, opening of deep gas-distillate production at Shongaloo, and completion of one well in a deeper horizon at Bluc Lake (Zwolle field). Geological Notes The deep drilling done in 1938 did not cause any important changes in geological correlation and nomenclature of the formations below the Upper or Gulf Cretaceous. The stratigraphic section of the Lower Cretaceous and deeper beds, with names used in the accompanying tables, as approved a year ago by the Shreveport Geological Society, is as follows:

Jan 1, 1939

By Michael Hoch, Daniel B. Butrymowicz

The isothermal section of the Ta-Ti-Zr-0 system at 1500°C was investigated using X-ray diffraction and rrzetallographic techniques. Up to 71.4 at, pct 0 the system contains nine four -phase regions. Zsopleths at 10, 20, 30, 40, 50, and 60 at. pct 0 were constructed. The purpose of this investigation was to determine the general shape of the quaternary equilibrium phase diagram of tantalum, titanium, zirconium, and oxygen at 1500°C. The system was truncated at 66.7 at. pct 0 on the Ti-0 and Zr-0 binaries and at 71.4 at. pct 0 on the Ta-0 binary. The Ti-Zr-0 system was investigated in this laboratory.' The binary systems of interest have been compiled and discussed by Hansen and Anderk, chmidt, Hayes, Roberson, and asche, and Hoch and athur.' EQUIPMENT The Same equipment as that for the study of the Nb(Cb)-Ti-Zr-0 system was used.' The X-ray dif- fraction patterns were analyzed with the help of the ASTM card set7 and NBS circulars.' MATERIALS The tantalum powder (99 pct pure), the titanium powder (99.6 pct pure), the tantalum pentoxide, and the zirconium dioxide used in this study were purchased from the Fairmont Chemical Co., Newark, N.J. The zirconium powder (99.4 pct pure) was obtained from the Charles Hardy Co., Inc., New York. Reagent-grade titanium dioxide was purchased from the Matheson Co., Inc., Norwood, Ohio. The oxides were dried in air at 700°C for 24 hr before use. Though the materials used were not "hyper-pure", the impurities present do not affect the results (lattice parameters, phase boundaries), within the experimental accuracy. PROCEDURE The samples were heated by induction in a vacuum furnace, and examined metallographically and by X-ray diffraction at room temperature. The procedure was the same as that in the Nb(Cb)-Ti-Zr-O work,' EXPERIMENTAL RESULTS AND DISCUSSION OF DATA A four-component system can be represented by a tetrahedron at a single temperature and pressure

Jan 1, 1964

By W. D. Grundy, Frances Wahl Pierce, Jean-Paul Marbeau, Carol Waite Conner

Resource and coal quality estimates of three coal deposits in the Western United States were estimated by kriging, a geostatistical method that yields unbiased estimates with maximum achievable precision. Derived geostatistical models were used in kriging to estimate the tonnages of the deposits and to derive contour maps of thickness, structure, and sulfur content. Where data were available on quarter-mile spacing, kriging was used to obtain detailed information applicable to mine planning and design. Where data were sparse, kriging was used to do a preliminary evaluation of total resources. Geologic studies were required to correlate the individual coal beds and to identify complicating conditions such as the presence of faults, burnt zones, channels, and regional changes in thickness and elevation. Where these conditions were identified, they were explicitly integrated into the estimation procedure.

Jan 1, 1983

By Frank E. Hall

The needs of the World War showed the necessity of a metal stronger than cast iron which would supplement the supply of steel. SO patriotic metallurgists were spurred to new efforts to improve the status of that half-breed of the metal world that had been, more or less erroneously, christened semisteel. As a result, it was developed that for certain purposes semisteel was superior to steel in the manufacture of shells. Steel, because of its greater strength and toughness, is able to carry a greater charge of explosive, weight for weight; consequently, a steel shell can be expected to cause greater destruction when used against fortifications or other inanimate objects, while semisteel, because of its comparative brittleness and its resulting greater fragmentation, is capable of inflicting more serious loss of life when used against opposing forces of men. Therefore, each has its proper place in the economy of war. For the present purpose, steel may be defined as a comparatively pure iron whose physical nature is modified by small amounts of carbon, silicon, sulfur, phosphorus, manganese, and possibly other rarer elements; while cast iron generally is limited to approximately 93 per cent. of iron, the remainder consisting of larger percentages of carbon, silicon, sulfur, phosphorus, and manganese. Semisteel may be defined as cast iron in which the carbon and silicon have been reduced to as low a point as is consistent with maintaining the nature of gray iron, and in which the remaining elements are adjusted so as to give the greatest strength. The fact that the addition of steel scrap, in varying percentages, is the means used to reduce the carbon, together with the fact that a considerable increase in strength results, is probably the explanation of the origin of the name semisteel. That ordinary grades of steel show from three to four times the tensile strength of cast iron is due to the fact that the crystals, or grains, of cast iron are interspersed with flakes of

Jan 1, 1922

By Frank E. Hall

The needs of the World War showed the necessity of a metal stronger than cast iron which would supplement the supply of steel. SO patriotic metallurgists were spurred to new efforts to improve the status of that half-breed of the metal world that had been, more or less erroneously, christened semisteel. As a result, it was developed that for certain purposes semisteel was superior to steel in the manufacture of shells. Steel, because of its greater strength and toughness, is able to carry a greater charge of explosive, weight for weight; consequently, a steel shell can be expected to cause greater destruction when used against fortifications or other inanimate objects, while semisteel, because of its comparative brittleness and its resulting greater fragmentation, is capable of inflicting more serious loss of life when used against opposing forces of men. Therefore, each has its proper place in the economy of war. For the present purpose, steel may be defined as a comparatively pure iron whose physical nature is modified by small amounts of carbon, silicon, sulfur, phosphorus, manganese, and possibly other rarer elements; while cast iron generally is limited to approximately 93 per cent. of iron, the remainder consisting of larger percentages of carbon, silicon, sulfur, phosphorus, and manganese. Semisteel may be defined as cast iron in which the carbon and silicon have been reduced to as low a point as is consistent with maintaining the nature of gray iron, and in which the remaining elements are adjusted so as to give the greatest strength. The fact that the addition of steel scrap, in varying percentages, is the means used to reduce the carbon, together with the fact that a considerable increase in strength results, is probably the explanation of the origin of the name semisteel. That ordinary grades of steel show from three to four times the tensile strength of cast iron is due to the fact that the crystals, or grains, of cast iron are interspersed with flakes of

Jan 1, 1922

By M. M. Austin

Pure metallic tantalum, from a practical standpoint, is one of the newer developments in the metal field. Although it was used as filament in incandescent lamps in 1906, only within the last, five years has the metal been available in sufficient quantity and suitable form for more general application. In addition to corrosion-resisting properties and high melting point, the metal has an ability to withstand unusual amounts of cold working. It affords some striking demonstrations of block movement during plastic flow. Strength and Ductility of Tantalum Since there is no good way of defining working properties numerically, illustrations will be used. It is possible to roll a bar of pure tantalum 0.4 in. thick to sheet 0.001 in. thick, without heating or annealing. The sheet produced will be sound and may be bent upon itself at right angles to the direction of rolling. Longitudinally the sheet will be somewhat brittle. A disk of annealed metal may be cupped and drawn to the form of a capsule 3/16 in. dia. by 146 1? in. long. If carefully handled this capsule can be further deformed by drawing to a tube having an outside diameter of 0.050 in. Disks of tantalum may be spun into tubes of 39 in. dia. and 1½ in. long. In the form of rod, reductions may be made from 0.4 in. to 0.001 dia. In the latter process, it is necessary to heat the wire four or five times to 500" C., at intervals between 0.040 and 0.001 in. Although the melting point of tantalum is 2850" C., these heatings at 500" C. are sufficient to distinctly anneal it. Published figures on the strength and ductility of tantalum are not particularly accurate. This is due to the fact that these properties vary widely, depending on the extent to which the metal is contaminated by gas. There are no sharp critical points in these changes with gas content; samples of metal will vary from a springy or actually brittle condition to one of leadlike softness. Samples that have had a prolonged heating at high temperatures in a good vacuum, under conditions such as would be provided in vacuum-tube experimentation, will yield a product of about the hardness of annealed copper. The usual commercial metal will have the hardness of annealed mild steel.

Jan 1, 1930

By S. R. Rao

Interaction of potassium amyl xanthate with pyrrhotite has been studied thermochemically. Heats of adsorption of xanthate on unactivated mineral and the mineral activated with cupric ions have been compared with heats of reactions between potassium amyl xanthate and ferrous and cupric salts. It is shown that xanthate is consumed by stoichiometric exchange with anions present at the mineral surface. The floatability of the unactivated mineral is poor since xanthate is precipitated in bulk without creating a hydrophobic surface on the mineral. At the activated mineral surface, xanthate is adsorbed in certain isolated patches (active spots) and thereby creates a hydrophobic surface. The hydrophobicity of the mineral is greatly improved by lowering the pH to 4.5.

Jan 1, 1972

By Henry G. Granger

DURING upwards of three thonsand miles of canoc-travel in South America, including several mishaps, the writer has unfortunately lost his book of notes taken during the year 1894 in Dutch Guyana, or Surinam. But a year spent in a foreign country, visiting its principal mining properties, is necessarily productive of indelible memories and impressions, and some of these may be of interest to the Institute. The Guyanas include British, or Demerara, Dutch, or Surinam, French, or Cayenne, and the Disputed Territory, or that portion of Brazil on the northeast coast of South America. After passing the picturesque mountainous coasts of Colombia and Venezuela, one reaches a low, flat mud-bank which extends far out into the sea, so that from the steamer, over a couple of leagues of turbid, shallow water, one call just see the dismal outline of the pestilential "bush" that fronts the Caribbean sea, clear around to the mouth of the Amazon. Here, iii the order mentioned above, are the Guyanas. So much has been said about this out-of-the-way section during the late excitement over the Venezuela boundary question, that the historical part of the subject may be advantageously condensed. Gold-mining in the Guyanas is altogether placer-mining, and is of the same general nature throughout; hence by describing the methods in use in Surinam and the results there achieved, ail idea will be given of the work throughout the field. The product of this section is about three to four millions of dollars annually, mostly from Demerara, not because of superior richness of its placers, but as a result of its very much larger population, which exceeds twice the aggregate census returns of both Surinam and Cayenne. Mining ill all this section is of comparatively recent date, and is indirectly due to the decline of the sugar-industry. After the introduction of beet-sugar scores

Jan 1, 1897

By T. M. Williams

DURING the year just ended we have had three great fires in the mines in the Wilkes-Barre district. One at the Empire Colliery, one at the Prospect shaft, and the other at the Baltimore old mine. It is proposed in this paper to give a brief history of the fire at the Empire Colliery, and the methods employed in extinguishing it. The fire was first discovered breaking out in the air-stack, alongside what is known as the " Kidder Plane," about one o'clock on the morning of December 31st, 1873. Subsequently it was ascertained that the fire originated in the return airway somewhere near the steam boiler, located inside the mine, near the head of No. 5 slope. The coal from this slope was hoisted to the shaft gangway, at a point nearly four thousand feet distant from the foot of the shaft. As there were from four to five hundred mine cars hoisted per day from this slope the steam boilers were located at this place. The mines being of considerable extent required a large volume of pure air for ventilation, and no fan having been erected at this slope at the time, the heat from the boiler was made use of to assist ventilation, by conveying the return air from No. 5 slope into the large airway made from these boilers to the surface through the old "Kidder slope" to the stack where the fire was first discovered. The length of this slope or airway was about one thousand feet, with a sectional area of about sixty feet. The quantity of air passing through it must have been over sixty thousand cubic feet per minute

By Joseph Jensen

When the legal holders of Government permits in the Middle dome of Kettleman Hills entered into an agreement on May 27, 1929, to suspend all drilling activities on five permits, covering portions of the Kettleman Hills Middle dome, until Jan. 1, 1931, and the owners of fee lands contiguous thereto assured Secretary Ray Lyman Wilbur, of the Department of the Interior, that they too would respect a drilling suspension for a period of a little more than 19 months, none of these interested parties realized that this was the first step in a chain of events that would culminate, more than four years later, in the formation of the Middle Dome Corporation for the development of the Middle dome area in a unit plan that would be the first unit plan to be approved by the California Regional Producers Committee and recommended to the President as a satisfactory unit plan, under Section 7 of Article III of the Oil Code, approved Aug. 17, 1933. Neither did they realize that more than two million dollars would be spent before oil or gas would be successfully and continuously produced from wells drilled on that Middle dome area. On Oct. 1, 1933, under the terms of the Middle Dome Agreement, the Middle Dome Corporation assumes control of activities and is responsible for the division of all product's produced from the Middle dome area to members of the Middle Dome Corporation. This Middle dome plan is the second successful unit plan developed in California in the past three years, the first being the Kettleman North Dome Associationll formed under the agreement, of Jan. 31, 1931, for the unified operation and development of more than 12,000 acres of land on the North dome of the Kettleman Hills. All other unit plans discussed in the past four years in the state have not yet been completed, for one reason or another, but under Section 7 of Article 111 of the new Oil Code numerous plans of development, some of which may be unit plans, will be forthcoming within the next few months. There is much

Jan 1, 1934

By David Donoghue

The efforts towards curtailment in Texas have been successful, despite the great area covered and the wide variety of oils offered. There are, of course, examples of noncooperation, perhaps of absolute indifference, but of such it can at least be said that they have benefited from the restrictions imposed elsewhere. The prevention of waste is the legal background for proration in Texas. The legislature in 1899 passed the first laws to prevent waste of oil and gas. Subsequent legislatures, especially those of 1905, 1913 and 1917, undertook to regulate the development and transportation of oil and gas to the end that waste would not occur. In 1917 a constitutional amendment was submitted to the people, providing that natural resources of the state should be conserved and requiring that the legislature pass appropriate laws. This amendment was adopted, and the Acts of 1919 and 1929 have been passed, and these have had the effect of making a rather elaborate plan for the conservation of oil and gas and their protection against waste. In 1930 the new pipe line act, designed to provide for ratable purchases, was passed. The administration of these laws has been placed under the Oil and Gas Division of the Railroad Commission of Texas. The Commission can only consider actual waste, not economic waste. The various proration plans in use in the state, while differing in efficiency, are based on engineering principles. In the proration of flush fields, the limiting of drilling and the steady production of oil under restriction are the principal points involved, and these methods are entirely different from those which prevailed until recently in the Oklahoma City Pool, where apparently nothing beyond the restriction of production on a time basis was attempted. There is little to say in defense of proration in the older and smaller producing areas in Texas, except that, inasmuch as the market outlet has been reduced, proration distributes the market ratably among the producers. Work of Central ProRation Committee In the early part of 1930 the overproduction situation became acute, and, at the request of the Railroad Commission, a committee was formed composed of representatives of the Texas Division of the Mid-Continent

Jan 1, 1931

By H. F. Seifert

The classification and preparation of non-ferrous scrap mctals is a subject of interest to every individual and corporation that employs in its processes of manufacture non-ferrous metals and alloys and accurnulates in such manufacture scrap from these materials for disposition in the form of turnings, borings, short ends, punchings, clippings, grindings, washings, etc. All too frequently the disposition of such scrap is left to indivitluals who have no knowledge of the subject either from a metallurgical or a commercial standpoint, or both. Much money is thus lost whicli with a little more intelligent effort might be saved, and in this day of fierce competition and small profits such an opportunity cannot be ignored. The Mineral Resources of the United States for the year 1925, the latest issue available (Part 1, page 221), gives the secondary non-ferrous metals of certain classes recovered in the United States for the year 1924 to 1925 as shown in Table 1. The figures are tabulated simply to give the reader some idea of the scope of the secondary non-ferrous metal industry. Approximately 900,000 tons of an annual value of $244,000,000 were recovered in the year cited. In 1916 (again using thc Mineral Resources of the United States as authority) the tonnage reclaimed was approximately 632,000 tons and the value, because of the high prices for metals prevailing at that time, amounted to $265,000,000. It is not the purpose of this paper to discuss smelting and refining operations or the feasibility of an organization, primarily engaged in some other activity, conducting smelting and refining operations to convert its own non-ferrous scrap metals and alloys. The classification and preparation of these non-ferrous materials is a preliminary step, regardless of what subsequent operations the material may pass through or where these operations may be conducted. For that reason the subject can he readily discussed without any reference to subsequent activities. Space must be provided, with suitable handling facilities, scales and the necessary storage bins where the material may be accumulated. The scope of the activity, the nature of the industry and the tonnage handled will determine, in a large measure, what preparation, if any, it rrlay he desirable to give these scrap materials to put them in the best niarketable condition. By preparation is rneant largely what, for the want of a

By Frank G. Norris

Slag control is adjustment of the composition of the slag, especially with respect to the FeO content. The theoretical method of slag control would be to charge a mixture of pig iron and scrap of given composition into the furnace, to melt always at the same carbon, and, after a uniform ore addition, to tap with a constant slag composition. Such conditions are not even approximated. Both scrap and pig iron are of variable, and, in many cases, unknown composition. The charge is oxidized to a variable extent during melting. The result is that the FeO content of the slag, and consequently of the metal at tap, varies over a wide range. In order to make a nearly uniform product, this variation must be compensated for in some way. One way is to adapt the ladle deoxidation to the requirements of the metal. The other is to control the slag. In a general sense slag control may be considered as a method of compensating for variations in the composition of the charge and in oxidation during melting. The method of slag control for low-carbon steel was developed by Dr. Herty at our Butler plant3. Use of this method enables the furnace operator to tap heats at a more nearly constant FeO content and, therefore, to use a more nearly uniform deoxidation practice. The desired FeO and the accompanying deoxidation will depend on the application of the product. This statement implies that 0.10 carbon steel finished with a 15 FeO slag may be essentially different from a 0.10 carbon steel finished with a 30 FeO slag. In making low-carbon steel, the desired carbon places a lower limit on the FeO content of the slag, because the slag must be sufficiently oxidizing for proper carbon elimination. With this degree of oxidation, the phosphorus specification is met without difficulty, and there is little danger of phosphorus reversion. Thus a limiting factor in high-carbon heats is of slight importance in low-carbon heats. For heats of 0.05 to 0.07 per cent carbon, the FeO content of the slag may be controlled at

Jan 1, 1935

By Harold H. Haman

In view of Twentieth Century advances in mineral dressing technology, most modern metallurgists would be inclined to class jigging as an early, somewhat primitive, representation of their art. The practice of metallic sulfide concentration by jigging is becoming rare. This is so, in part, because the type of ore amenable to the process is becoming rare. It is appropriate, however, that this symposium recognize that a significant contribution of domestic zinc remains dependent upon coarse preconcentration by jigging, and that the state of the art be described even though the theory and applications are already well delineated in technical literature. One of the few areas still using jigging as a major concentrating process is The Upper Mississippi Valley. AREA HISTORY AND JIGGING The Upper Mississippi Valley (UMV) has produced one billion dollars worth of zinc and lead at current prices. The district includes the southwest part of Wisconsin, the northwest corner of Illinois and an adjoining narrow strip of Iowa. Within a total area of 4,000 square miles, important sub-districts cover about 400 square miles. As is widely known, early mining in this district involved shallow lead---crevice deposits of galena that were very selectively mined, hand sorted and cleaned, and then smelted at or near the site. The district has produced almost a million short tons of metallic lead, a very large part of this during the fifty- year period following 1830. Zinc mining began at the end of the civil war, but at a very low rate until about 1905.

Jan 1, 1970

By Ernest R. Darby

If the correct balance between fuel and air is maintained in an open-flame furnace,' little chemical action may be expected between the products of combustion and the metal being melted. Physical' changes in the metal are the object of the melting operation, and indirectly, under certain conditions, may be the cause of subsequent chemical actions. If sufficient heat has been introduced into the metal to bring about the change from the solid phase to the liquid phase, and still further from the liquid to the vapor phase, the metal vapor in all probability will be carried from the furnace by the exhaust and rapidly combined with the oxygen of the outside air. The charge being melted in the furnace may contain elements which are chemically inactive at normal temperatures but which will form compounds at the elevated temperatures of the metal bath, or even at a lower degree. Such indirect chemical actions are very confusing and often lead to incorrect conclusions regarding furnace atmospheres. In the open-flame furnaces used in the melting of bronze, the furnace atmosphere is spoken of as being either neutral, oxidizing or reducing in its effect upon the metal. A neutral atmosphere, as mentioned, is generally considered as the atmosphere of the furnace that will produce melted bronze, neither oxidized nor gassed. It is in effect an atmosphere which is not directly the cause of any chemical action. In such an atmosphere absolutely pure metals may be melted and poured without the absorption of gases or the formation of metallic oxide. The metal has undergone a simple, physical change. An oxidizing atmosphere is one in which the air introduced to the furnace is in excess of that required to complete combustion of the fuel used. The oxygen of the excess air may combine with the metal being melted to form metallic oxide, which may or may not be dissolved by the metal. If an absolutely pure metal is melted in a furnace operating with such an atmosphere, a portion of the metal charged may be converted into metallic oxide, the amount depending upon the duration of the

Jan 1, 1930

By Frank G. Norris

Slag control is adjustment of the composition of the slag, especially with respect to the FeO content. The theoretical method of slag control would be to charge a mixture of pig iron and scrap of given composition into the furnace, to melt always at the same carbon, and, after a uniform ore addition, to tap with a constant slag composition. Such conditions are not even approximated. Both scrap and pig iron are of variable, and, in many cases, unknown composition. The charge is oxidized to a variable extent during melting. The result is that the FeO content of the slag, and consequently of the metal at tap, varies over a wide range. In order to make a nearly uniform product, this variation must be compensated for in some way. One way is to adapt the ladle deoxidation to the requirements of the metal. The other is to control the slag. In a general sense slag control may be considered as a method of compensating for variations in the composition of the charge and in oxidation during melting. The method of slag control for low-carbon steel was developed by Dr. Herty at our Butler plant3. Use of this method enables the furnace operator to tap heats at a more nearly constant FeO content and, therefore, to use a more nearly uniform deoxidation practice. The desired FeO and the accompanying deoxidation will depend on the application of the product. This statement implies that 0.10 carbon steel finished with a 15 FeO slag may be essentially different from a 0.10 carbon steel finished with a 30 FeO slag. In making low-carbon steel, the desired carbon places a lower limit on the FeO content of the slag, because the slag must be sufficiently oxidizing for proper carbon elimination. With this degree of oxidation, the phosphorus specification is met without difficulty, and there is little danger of phosphorus reversion. Thus a limiting factor in high-carbon heats is of slight importance in low-carbon heats. For heats of 0.05 to 0.07 per cent carbon, the FeO content of the slag may be controlled at

Jan 1, 1935