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By L. H. Marshall

MALLEABLE-IRON castings frequently are made brittle by hot-dip galvanizing. The castings may be and usually are perfectly normal before the hot-dip treatment, in that they will stand a remarkable amount of distortion and punishment before fracturing, yet, after galvanizing, a single blow with a hammer will often cause a break. One such casting broke when accidentally dropped on a concrete floor. Such weakness causes galvanizers to view malleable cast iron with misgivings, and, in turn, is a source of worry to the manufacturer of the castings. It is felt, therefore, that a practical method of overcoming this embrittlement, a method that has already been used on several thousand tons of castings, will be of general interest. The purpose of this paper is to describe this immunizing process. DEVELOPMENT OF THE PROBLEM In the early days the trade was not much concerned with the finish of the castings and in most cases the only protection given to the parts placed in service was a coat of paint. It was soon found that this form of protection was inadequate and the user demanded a better type of rustproofing. In compliance with this demand, the use of zinc for coating gradually spread until it became general practice. More than half of all the zinc produced today is used for coating iron and steel, and, in spite of the recent use of cadmium and chromium, zinc coatings are still recognized as among the best general rust inhibitors for atmospheric exposure.

Jan 2, 1926

By A. R. Troiano, W. J. Barnett

IN recent years the demands of space limitations and increased loads, particularly in the aircraft industry, have accelerated the trend toward utilization of ultra-high strength steels. The increased application of such steels has focused attention on the phenomenon of delayed failure or static fatigue. Parts subjected to a static load, after successfully sustaining the load for an extended period of time, may fail in a brittle manner. Subsequent examination of such failed parts by conventional laboratory tests in many cases reveals no apparent signs of embrittle-ment. That is, the material exhibits good ductility and impact resistance. Furthermore, consideration of the service conditions (environment and temperature) under which this brittle failure occurred eliminates its classification as a stress-corrosion or creep type of failure. Recently this unique time dependent fracture process has been the subject of numerous investigations. The most significant result of these studies was the recognition of hydrogen as the source of embrittlement. While the effect of numerous variables on the occurrence of static fatigue failure has been defined, an adequate explanation of these behaviors is lacking. The occurrence of this phenomenon in steels generally has been limited to strength levels in excess of 180,000 lb per sq in. Although steels at high hardness levels have exhibited delayed failure in the absence of hydrogen introduction after heat treat-ment,'.' this behavior was most prevalent when the material in processing had been subjected to an environment conducive to the absorption of hydrogen. Delayed failures have been produced in high strength steels by the introduction of hydrogen

Jan 1, 1958

By A. S. Richardson

THE rating of a mine ventilation fan, or the characteristic curves illustrating the duty it may be expected to perform under various mine conditions are, in general, determined by the fan manufacturers. The information is of importance to the operator, or engineer, of a mine in many ways. For instance, when an increased flow of air is desired and the fan speed is to be increased, it becomes necessary to know what increase in volume may be expected and what the power requirements will be. In other cases, it may be decided to make changes in the mine to reduce the resistance to the flow of air, or to make changes in the general system of ventilation. Under any changed mine conditions there will be a difference in the duty performed by the fan. When mechanical ventilation is adopted, the factors governing the selection of equipment for the new system include not only the requirements of existing conditions, but also those that may be expected with the development of the property. Efficiency of service is required over a variable range of operating conditions. Characteristic curves, giving the duty performed by their fans under variable resistance conditions, are published by most fan manufacturers. General statements as to the effect of variation in speed of the centrifugal-type fan, under fixed mine conditions, appear in textbooks and trade catalogs. However, to the author both sources of information appear to be unreliable, at least under certain circumstances. The catalog of a leading fan manufacturer says: 1. The volume of air delivered by a fan varies directly as the speed. 2. The pressure, or water gage, produced by a fan varies as the square of the fan speed. 3. The horsepower of a fan varies as the cube of the fan speed. While these statements are accurate when the fan is operating under conditions similar to those that exist when a blower is used to force air through a pipe, they are not correct under mine conditions that are by no means unusual. Such conditions may be found in deep mines operated through shafts, in which a wide range of temperatures may be

Jan 8, 1925

By C. H. Hitchcock

A brief resiclence in Virginia hasenabled me to examine some of its crystalline strata, and a few hints, concerning their correspondence with similar rocks elsewhere, may be of service to those who are studying them. In comparing the crystalline rocks of Virginin and New England, we may first recall the similarity of their geographical position. They constitute a continuous belt, being traceable through the Highlands of New York and yew Jersey, Southeastern Pennsylvania, in the counties of Bucks, Montgomery, Philadelphia, Delaware, and Chester, and Marylund. Thus the Green Mountains of Vermont and the White Mountains of New Hampshire seen] to be topographically continuous with the Blue Ridge and Midland districts of Virginia. This tract of country has been termed the Atlantic area in distinction from the Appalachian territory, whose eastern limit is the great, Lower Silurian limestone valley extending from the St. Lawrence and Champlain valleys to Alabama. The Appalachian formations were studied by the brothers Rogers, forty years since, and found to refit, unconformably upon the western flank of the Blue Ridge, the oldest of the series adjoining the gneisses, followed westerly by the other Palseozoic members in a regular ascending order, to which numercial designations were applied—Number 1 being the Cambrian, Number 2 the Lower Silurian Iimeqtones, etc?. In Vermont the same conclusion Was presented in the State reports: the Green Mountains were said to possess the anticlinal structure, and to underlie the quartzites and limestones. Inasmuch as this Atlantic area is' topgraphically continuous from the Middle to the Northern States, and is unconformably overlaid upon the west side by the same succession of strata, the presumption ii very strong that the history of bath sections has been the same, and that the entire area is of Eozoic age. Cross sections, in both districts, illustrate the existence of gigantic overturns, causing the strata of 'the Appalachian region to dip to wards the Atlantic gneisses. To the beginner it would appearthat tile Silurian group must dip beneath the crystallines, and hence many of the geologists in the beginning of the study of the stratigraphy of this easters border of the continent believed that

Jan 1, 1882

By Henry M. Howe

1. The purpose of the National Research Council as organized for war purposes is twofold, to stimulate those outside its own personnel to conduct researches of importance for winning the war and to carry on such researches through its personnel to a limited extent. How this is done is explained in Section 10. "Research" is used here in a very broad sense, including, for instance, inventing and developing mechanical and physical devices. The need of this work arises from the inevitable concentration of most of the governmental war agencies on the production and transportation of war materials of the types now adopted, as distinguished from devising new kinds of instrumentalities, such as armor, guns, aircraft, and apparatus for detecting, locating, observing, signaling, transporting, and many other military purposes. But it is important that we should devise new agencies. The war came near being won by an invention, the submarine, and its course has been affected greatly by two other inventions, tanks and aircraft. In spite of our numerical superiority victory may well be snatched from us by an invention, if we allow Germany to outstrip us in inventing. Hence the importance of the Council's work in mobilizing and organizing the services of the patriotic civilian experts throughout the country, so as to bring their powers to bear on important war problems and on inventing war devices, as an adjunct to the development work of the regular governmental bodies. 2. Status of the Council.—Though President Wilson's request caused the Council to be created in 1916 by the National Academy of Sciences under its congressional charter; though his executive order of May 11, 1918, directs the heads of "Governmental departments immediately concerned" to "continue to co-operate with it in every way that may be required;" and though the Government has contributed largely to its financial support; it is not a department of the Government but an independent research body, aiming to evolve the necessary mechanism for the novel work of systematic stimulation and guidance of research. Thus the Government, which instigated the creation of the Council, recognizes and collaborates with it, and in part supports it. The Council acts moreover as the Department of Science and Research of the Council of National Defense.

Jan 1, 1919

AT the meeting of the Board of Directors in March 1945, plans were discussed for a special General Meeting to commemorate, in an appropriate way, the founding of the Institute at Wilkes-Barre, Pennsylvania, in 1871. It was decided that seventy-five years of growth, progress, and achievement; of service to the profession, to the mineral industry in all its branches, and to society at large should be fittingly celebrated. Harvey S. Mudd, then President of the Institute, was authorized to appoint a General Committee on Arrangements as well as necessary working committees. On June 6, 1946, Louis S. Cates, as President, at a special meeting of the Pennsylvania-Anthracite Section at Wilkes-Barre, officially announced plans or a three-day meeting to be held at The Waldorf-Astoria, in New York City, September 16-18, 1946. Four major sessions to be addressed by eminent speakers had been-planned in some detail to constitute a "World Conference on Mineral Resources." The U. S. Department of State had dispatched a 1500-word airgram to all its diplomatic posts giving worldwide publicity to the scope and importance of the meeting; and formal invitations had been issued to more than 150 institutions in 40 foreign countries to send official delegates. These included scientific and engineering societies, educational institutions, and sundry government agencies connected with the mineral industry. However, about a month later it was found necessary to postpone the celebration. The reason was an unforeseen expansion in the requirements of the United Nations for hotel living space in New York to accommodate delegates to the meeting scheduled to start September 3; and, of course, U.N. delegates would be given priority. It was decided to postpone the Celebration-conference to the week beginning March 17, 1947; t6 devote the first three days primarily to the Celebration; and to follow it with the technical sessions, committee meetings, and other functions, that are regular features of the Annual Meeting. To accommodate the combined "show" it would be necessary to hold some of the Annual Meeting sessions at another hotel;

Jan 1, 1947

By Richard Moldenke

The author discusses some economic conditions which have made the career of the cast-iron pipe industry in the United States a checkered one. He next describes the two new developements in the manufacture of cast-iron pipe-both along the lines of centrifugal casting. The advantages and disadvantages of both processes are presented in some detail. Finally, statistics on the production of pipe in the United States at the present time are given, as well as the plants-and their capacities-so far as these are situated in the South. No SINGLE branch of the foundry industry has been brought to a production basis of huge tonnage, low manufacturing cost, and producing material of a remarkably high quality, as has the making of cast-iron pipe. The pipe shop is an excellent illustration of the fact that repetition work in specialties leads to mechanical equipment and manipulation that lower production costs to an. astonishing degree. Hence cast-iron pipe, in dull times, has been sold at a few dollars a ton over the selling price of the pig iron used. On the other hand, these same pipe, shops make fittings .of many varieties, and in much smaller quantities, where the cost is high, and when pipe may be sold, say, at $50 a ton, the fittings on the same shipment will be sold for nearly double that price. The history of pipe-making, in the United States, is a checkered one the mortality of plants is high and, from the nature of the industry, plants must be large to live. In spite of the fact that the best processes must be used to turn out this rather strict specification material, pipe is easy to make and a pipe plant is more of a tonnage mill than the really high-class specialty foundry it should be. Every time, therefore, that the demand for pipe is strong new shops spring up, only to close when the demand has ceased, but the financial damage to the more permanent plants has been done. Both the South and the North have had abundant experiences of this kind, and when recently a northern Public Service Corporation gave its order to France, the pipe plants thus adversely affected were content to have this occur rather than see-a plant started to supply the surplus demand.

Jan 9, 1924

By H. F. Moore

AT PRESENT, I am connected with an investigation of the so-called fatigue of metals under stress. So far we have studied the more fundamental and simple case of the repeated stress, without the additional complexity of impact, which might bring in other factors. We feel that this investigation, which has been in active progress for a little over a year, has shown more conclusively than has been shown before that steel under repeated applications of stress, reversed from positive to negative, will not fail below some fairly clearly defined limiting stress that,, so far we can see, does not bear any definite relation to the ordinary elastic limit, being as large as the elastic limit in some cases and about one-half the elastic limit in others. I might be asked, first, what is fatigue. The old view is summed up "in the word "crystallization." The idea was that under repeated stress the material changed its crystalline structure. I do not know of any evidence in favor of the theory that metals materially change their crystalline structure under repeated stress. The crystals are broken under repeated stress. The second theory, advanced by Bauschinger, the German scientist, is that under repeated stress some inherent property of the material changes its elastic limit; it is an inherent property of the material, possibly some property of the amorphous cement between the crystal. The third view is that all fatigue of metals is the result of the spread of damage from little localized overstresses. I do not feel justified in stating my positive belief in the third view as against the second, but I have yet to run across a case of failure of steel or other metal, either in the laboratory or in service, that could not be explained by the gradual spread of damage from some nucleus. We have found, for example, that it is possible to subject a homogeneous steel, like Armco iron or a 0.90 per cent. carbon steel, that hag been thoroughly annealed, to one hundred million reversals f stress as high as the elastic limit of the steel with no sign of failure. We stopped the test at one hundred million because the machines Were required for other work. Forty-five days, continuous running at 1500 revolutions a minute is required to produce one hundred million repetitions. On the other hand, a complex structured steel, like a chrome-nickel steel that

Jan 6, 1921

With the inauguration of Petroleum Technology this year, and approval by the Board to add an Assistant Secretary to the New York staff to serve the Petroleum and Coal Divisions, the Petroleum Division looks forward to greater opportunities and responsibilities. An improved medium of publication offers further incentive to engineers and investigators in the oil industry to make contributions. The authorization by the Board of Directors of a new Assistant Secretary is an appreciation of the splendid contributions made to the industry by the open forum of the Petroleum Division. It is also a recognition of the possibilities of greater service to the membership along the lines established ten to fifteen years ago by DeGolyer, Fohs, Ambrose and Lovejoy, to mention a few leaders. It isexpected that the new officer will spend a substantial part of his time in the field, visiting the student sections, the respective Divisions, helping in the arrangement of papers and Section meetings and intensifying interest in the Institute. The Petroleum Division will hold three meetings this year. The Fall Meetings will be held on Oct. 6 and 7 in San Antonio and on Oct. 20 and 21 in Los Angeles. The programs for these meetings will deal chiefly with engineering research and production engineering problems. Papers on production statistics and general economics of the industry are reserved for the Annual Meeting in New York. The annual production symposium and statistics are accepted as standard for the industry. With continuously deeper penetration into the earth in search for and exploitation of petroleum, it is necessary to have a better understanding of reservoir conditions and to place more phases of the operation under engineering control. Among the subjects relating to reservoir conditions tha thave been proposed for the fall meeting programs are phase equilibria at high pressures, interfacial tension between oil and water, the flow of oil and water through sands, the chemistry of films and underground temperatures. Investigations relating to control of operations include methods of continuously logging while drilling both visually and electrically, methods of studying drilling samples, properties of drilling fluids, improved cementing practices for isolating thin sands under high-temperature conditions and gas conservation, particularly production from high-pressure reservoirs. Additional suggestions of general themes or individual subjects will be welcomed, since it is desirable to build a backlog of material for Petroleum Technology. 9

Jan 1, 1938

By Felix B. Shay

THE Agua Fria mine is in eastern Honduras at Lat. 140° 06' N., Long. 86° 36’ W. Danli, the seat of the local municipal government, is the nearest town. The property is approximately 44 miles east of Tegucigalpa, the terminus of a truck road from the Pacific coast. The mine lies at an altitude of 3300 ft. with surrounding elevations as high as 6000 feet. For 20 years the oxidized croppings of the Agua Fria vein had been worked intermittently when in 1927 an attempt was made to open the property. A shaft was sunk 300 ft. and considerable ore was blocked out, but before a mill could be installed financial difficulties arose and the mine reverted to the original owners. Erle P. Halliburton, of Los Angeles, purchased the property in 1934. At that time a careful consideration of all factors involved showed that air transport was the only practical method of moving the equipment and machinery necessary to commence production. The other alternative was by muleback, which required sectionalizing all equipment to a maximum load of 200 lb., and during the rainy season this type of freighting was subject to serious delays. It was decided to purchase a trimotor Ford powered by three Pratt and Whitney Wasp B motors developing 400 hp. each. There were several reasons for the choice: (1) this type of plane was available at a reasonable price, owing to its replacement by faster models on most of the airlines in the United States; (2) the ship was capable of carrying a pay load of 3000 lb. over the required distance; (3) since this airplane had been widely used there would be no difficulty in securing competent personnel or in purchasing spare parts. It was necessary to rebuild the plane for cargo service. The windows were removed and the fuselage was entirely covered. A hatch was cut in the top of the fuselage to receive heavy crane loads and pieces of freight that were too large or too long to go through the rear door. The seats were removed and the interior of the plane was lined with Duralumin sheets. A heavy-duty landing gear was installed and the floor was reinforced. The nearest site for an airport was two miles north of the mine. The necessary grading was done by a small track-type tractor with a wheeled grader, which was brought in overland. Six weeks was required for bring-

Jan 1, 1940

By Alfred James

John Stewart MacARthUr, born in 1856, was the son of Robert MacArthur of Glasgow, and came of Scots stock distinguished for character and religious conviction. His election as elder of the Free Kirk gave him greater pride than the receipt of the gold medal of the Institution of Mining and Metallurgy. The former honor was for character— it marked him as a son worthy to follow in his father's footsteps; the latter was awarded for his life work of eminent service to the gold industry. Cheery optimism, resolution, tenacity of purpose, and industry ever characterized his actions. Apprenticed to the Tharsis Sulphur & Copper Co., his work on the chemical staff brought him to the notice of the Cassel Gold Extracting CO.,. at that time struggling with an unworkable electrolytic process..He was engaged by that company, in 1886, as technical manager and before long brought out the perchloride process, which was speedily followed (in 1887) by the epoch-making cyanide process. This process revolutionized gold mining and directly led the way to the elevation of the mining engineer to the most broadly trained product of the engineering profession. A noteworthy feature of the cyanide process was its completeness when introduced. Over thirty years have elapsed and the use of the process has been worldwide, but no suggested improvement has stood the test of time. The extension of the process to the beneficiation of silver ores—containing far more metal per ton and thus requiring the employment of stronger solutions—has brought us the Merrill and Crowe improvements in precipitation and the Nipissing desulfurization process for certain silver-hearing minerals. Roasting apparatus, fine crushing, filtration, and settling equipment have all aided the extension of the process in and from its original field. As Hennen Jennings put it,, the cyanide process today is essentially that of 1890. This self-containedness of the cyanide process arose from no mere chance; it was directly due to MacArthur. It was he who personally investigated every known method of precipitation and then every form of zinc from sheet, punchings, filings, millings, rods and shaving down to fume; it was he who investigated the effect of protective alkalies, of so-called accelerators, and of the addition of lead salts; he was determined to leave nothing to chance.

Jan 1, 1921

Your esteemed favors transmitting my discharge as your representative on the War Minerals Committee have come duly to hand and the kind words of commendation contained are greatly appreciated. Like other war committees, The War Minerals Committee's business in Washington was to meet an emergency as best it could, and as soon as the emergency had passed pressure of personal responsibilities immediately scattered the individual members. A detailed report of the Committee's work is therefore impossible. But before the matter is closed I feel it incumbent on me to ask you to report to the Directors and the Council, and through them to the members of the Institute and of the Society, the inestimable value to our Committee of the unstinted support given by both your officers and members. The instant response to all requests for funds was of the greatest assistance in getting started with office force, stationery, etc., and led later to a regular organization in the Bureau of Mines, working under a special appropriation, which is still doing good work as the War Minerals Investigation under Dr. Spurr. The voluntary work of the special sulphur and manganese committees formed by the War Minerals Committee was of great value to the Government. Copies of private reports supplied were of much assistance. But the great service of engineers and geologists as a whole was rendered in connection with the passage of the War Minerals Bill by Congress. Though every assistance possible was rendered by the Bureau of Mines and the Geological Survey, by the close of 1917 our Committee had about reached the limit of its usefulness in the way of stimulating the various Government executive committees, bureaus and departments to a realization of the country's need of preparation for domestic production of "war minerals" and had found that special Congressional action was imperative if the war was to continue for anything like the time then generally feared. This was necessary not only 'to insure a. supply of war minerals but to make possible the appointment of some able mining administrator of large experience in the mineral industry who, with ample authority, could sit in the councils of the Government and see to it that the ever increasing autocratic powers the war was developing were used toward the mining industry so as to foster rather than crush the latter in its effort to produce sufficient raw material for war and essential civil requirements.

Jan 7, 1919

By Norman F. Patton

The subject assigned is so broad that thorough discussion is well-nigh impossible within the space allotted, and further, few specific data are available upon which to predicate conclusions concerning the efficiency of present methods of distributing anthracite. This paper treats briefly the various agencies through which both primary and secondary distribution are effected, the methods of transportation and the general interrelation of production, demand, inventories and price. Avenues of Distribution Three distinct types of primary distribution are common in the marketing of anthracite. First, though not most important, is the sale by the producer, or operator, direct to the consumer. These sales, other than to employees and the local trade, are generally confined to steam sizes for industrial uses, and are consigned to the sidings or docks of the consumer. Sales of this type often are so closely priced to compete with oil and bituminous that the addition of even a small dealer's margin is sufficient to increase the cost to the point where the business might be lost. Second, the operator sells to a wholesaler or broker for subsequent resale, either to a retail dealer for clearance through his yard or direct to large consumers. Usually this method of distribution is employed by the smaller operators, who do not find it economically feasible to maintain extensive sales organizations. In most instances, the wholesaler retains some 5 per cent for his services, paid, of course, by the producing company whose anthracite he handles. He may, and frequently does, handle the output of several different companies, suited to the varying needs of the different communities he serves. His business includes all sizes of anthracite. The third, and by far the most general method, consists in selling to retail dealers, shipments being made direct from the breakers to the yards of the dealers. In large consuming areas, such as the metropolitan districts of New York or Philadelphia, one operator may sell to several

Jan 1, 1936

By Thomas Fraser, Robert MacLachlan

The dry cleaning of coal is a relatively new art and, as might have been expected, a number of unforeseen problems have been brought to light in the few years that dry methods of treatment have been in commercial use. The pneumatic concentrators that were first adapted to the cleaning of coal had already been developed to a fair degree of efficiency, although at low ratings, in the field of ore dressing. The concentrating machines, therefore, were in a relatively more perfected state than the general technology of dry cleaning and, for this reason, the major difficulties encountered in the early plants were in the accessory operations involved in the servicing of the cleaners rather than in the functioning of the cleaners themselves. The crudities of a new technology were further aggravated, in some cases, by meagerness of appropriations which precluded even the provision of adequate storage bins and such other facilities as had been long recognized as indispensable to the proper functioning of older types of cleaning plants. The practice of dry cleaning is now sufficiently established so that we may examine critically auxiliary equipment and operations. The cleaning processes have been so simplified, with respect to presizing of the raw coal required and the quantity of air circulated, that stinting of expenditures for auxiliary equipment is not necessary to keep the per ton cost of installation in line with complete and well designed plants of other types. Furthermore, sufficient operating experience has been accumulated to ascertain the conditions most conducive to effective operation of dry-cleaning machines; at least the essentials of a definite technology of dry cleaning has been established. Early Operating Problems The problems that have occupied the builders and operators of dry-cleaning plants from the beginning have been relatively few, but difficult of solution. The principal difficulties have been: 1. The proper sizing of the raw coal to suit the cleaning process. 2. The handling of raw coal when it is delivered wet from the mine. 3. Dust collecting. 4. The maintenance of uniformity in cleaning performance.

Jan 1, 1931

By Norman F. Patton

The subject assigned is so broad that thorough discussion is well-nigh impossible within the space allotted, and further, few specific data are available upon which to predicate conclusions concerning the efficiency of present methods of distributing anthracite. This paper treats briefly the various agencies through which both primary and secondary distribution are effected, the methods of transportation and the general interrelation of production, demand, inventories and price. Avenues of Distribution Three distinct types of primary distribution are common in the marketing of anthracite. First, though not most important, is the sale by the producer, or operator, direct to the consumer. These sales, other than to employees and the local trade, are generally confined to steam sizes for industrial uses, and are consigned to the sidings or docks of the consumer. Sales of this type often are so closely priced to compete with oil and bituminous that the addition of even a small dealer's margin is sufficient to increase the cost to the point where the business might be lost. Second, the operator sells to a wholesaler or broker for subsequent resale, either to a retail dealer for clearance through his yard or direct to large consumers. Usually this method of distribution is employed by the smaller operators, who do not find it economically feasible to maintain extensive sales organizations. In most instances, the wholesaler retains some 5 per cent for his services, paid, of course, by the producing company whose anthracite he handles. He may, and frequently does, handle the output of several different companies, suited to the varying needs of the different communities he serves. His business includes all sizes of anthracite. The third, and by far the most general method, consists in selling to retail dealers, shipments being made direct from the breakers to the yards of the dealers. In large consuming areas, such as the metropolitan districts of New York or Philadelphia, one operator may sell to several

Jan 1, 1936

By Carle Hayward

SULPHUR has long been one of the banes of the steel manufacturer and often no effort and expense have been spared in order to reduce it to a small per cent. in the finished product. This condition is clue to a general conviction that in many cases where steels have failed in service, sulphur has been the cause. But there has been a growing feeling in recent years that the verdict against sulphur has been unnecessarily severe. In cases of segregation it was present in augmented amounts along with other impurities, but it had not caused the segregation. High sulphur in pig iron is caused by poor furnace conditions and the sulphur is merely one indication of an iron that has not been properly reduced. No amount of subsequent treatment under oxidizing conditions in the open-hearth furnace can remedy the defects, although the per cent. of sulphur may be considerably reduced. In other words, the causes of bad steel can frequently be traced back to bad pig iron, and sulphur is merely one indication that the pig iron is bad. The writer recently visited a steel plant where a mass of evidence had been accumulated which substantiated this fact, and the superintendent was .emphatic in stating that high sulphur was not harmful provided the steel was not otherwise poor due to insufficient reduction in the blast furnace. The presence of a moderate amount of sulphur is desirable from the standpoint of the man who machines the steel. The low-sulphur material drags and the production of a smooth surface is very difficult. A slight increase in sulphur enables the machinist to produce a smooth surface without difficulty. Since, therefore, such large quantities of steel are subjected to machining, it becomes highly important that the sulphur controversy should be settled, and if its presence is proved to be harmless the ban on it should be lifted.

Jan 10, 1916

By R. P. Heuer, Paul M. Tyler

THE literature on refractories, although fairly extensive, is so scattered through books and periodicals as to be difficult of access to the general reader and most of the individual papers serve merely to illuminate some particular phase of the industry. Two general treatises by American authors8.16 are available, also the somewhat older works by a well-known British authority, 12,13 but these make their appeal to the technically minded ceramic engineer. Another small group of publications deals with the use of refractories, mainly in the iron and steel industry.1, 3,5,6,11,15 Raw materials utilized by the refractories industry have been covered by sundry books and articles. For the relatively nontechnical reader and economist, however, there appears to be no single review that purports to describe the industry as a whole. Furnace linings and other products that are classed as "refractories" are designed primarily to withstand high temperatures but this important property is by no means the only requirement; a suitable refractory material must likewise withstand slagging (chemical' action), abrasion (physical wear), and spalling, as well as the various other stresses and physical phenomena induced by heat, of which softening or incipient melting is only one phase. Nevertheless, subject to these highly practical considerations, the definition of a refractory material is based upon temperature resistance. Broadly speaking, any material that shows obvious signs of fusion after being heated slowly to 1500°C (2732°F) cannot be classified as a refractory material. The characteristic properties and requirements of refractory materials are conveniently summarized in Fig 1, prepared on the American Refractories Institute Fellowship at Mellon Institute, Pittsburgh, Pennsylvania. Most of the factors of service and properties of refractories given in this chart are interdependent and are greatly affected in degree by the functions of temperature and time. The factors in the chart are believed to cover the commoner questions.

Jan 1, 1949

By Horace Knerr

The term. "high-yield-strength," used in the title of Dr. Gillett's paper (p. 40) is obviously relative. His discussion is limited to improved steels intended to compete with the low-cost, low-carbon, hot-rolled, sheet and plate steels of commerce made and used on a tonnage basis, without heat-treatment. In his list of about three dozen steels, only three have a yield strength of 70,000 lb. per sq. in., or over. Double such values are not uncommon in aircraft steels. Dr. Jeffries (p. 21) refers to "light-weight metals," obviously meaning strong alloys of low specific gravity; namely, aluminum alloys of the duralumin type and certain magnesium alloys. In a structural material, "lightness" is determined by two factors, strength and specific gravity. They must always be considered jointly. The basis of comparison is a strength-weight ratio, obtained by dividing the desired strength value, such as tensile strength, yield strength, or endurance limit, by weight per unit of volume, such as specific gravity or pounds per cubic inch1. For example, aluminum is a heavy metal, structurally, unless alloyed and heat-treated to give it high strength. When the strength of a structural metal is raised by heat-treatment or by cold-work, its specific gravity is not appreciably changed, but it is made lighter in direct proportion to the increase in strength because less of it will be required to carry the load. The lightness of the finished structure of adequate strength is the real point of interest. This structure must not only carry designed load, but "stand the gaff" of service, which includes the effects of accidental overload, fatigue, corrosion, loosening of joints, and so forth. Neither Dr. Gillett nor Dr. Jeffries mentions the true "lightest material of construction," which is alloy steel, tubular in form (Fig. 1), assembled by welding and heat-treated to a yield strength in excess of 150,000 lb. per sq. inch.

Jan 1, 1936

By R. J. Wensley

The use of small substations for the supplying of 275-volt energy to the locomotive and cutting machines in coal mines is a well-established practice. A few years ago, when labor costs were lower, these substations were located as near to the load as possible, and an operator was provided for each station. This practice has now become so expensive that substations are being located with reference to other mining machinery, such as hoists or pumps, so that one operator can look after both. Sometimes the substation is operated by one whose duties make him traverse quite a large area. In such cases the interruption of alternating-current supply may produce a long interruption in the direct current, as the station cannot resume service until this man reaches it. Such interruptions interfere seriously with production and may easily counterbalance the supposed saving gained by such operating methods. The grouping of substations for convenience in operating may also result in excessive copper loss and consequently poor trolley voltage, with its attendant evils of low locomotive speeds and increased locomotive motor maintenance. The speed of the coal-cutting machines will also be reduced. By relieving the substation of its burden of the operating labor cost, the most economical location, from an electrical standpoint, may be chosen. The matter of machine insurance should also be considered. If an attendant is caring for several kinds of equipment, he cannot watch the machine continually for signs of trouble; therefore, continued overload, phase failure, low alternating-current voltage, bearing trouble, etc. may result. Some partly automatic equipments have been installed; these have protection against low voltage, reverse current, and bearing trouble and are provided with automatic reclosing circuit breakers. This is a step in the right direction but it does not go far enough to give first-class machine insurance. The saving in maintenance costs is often the smallest item, when considering the automatic substation as machine insurance. When the coils in a machine are roasted out, due to continued overload or to opera-

Jan 1, 1922

By A. E. Bellis

THERE is a wide difference of opinion among rifle experts in the matter of barrel steel, and the relative importance to the life of the barrel of the steel's composition, heat-treatment, structure, and physical properties. In order to promote discussion, which it is hoped may lead to the discovery of the source of 'some of the traditional beliefs on the subject, the results of some tests are presented here, with data on heat-treating, physical tests, and erosion. The detailed metallographic study of this steel is given in another paper.1 The conclusions from these tests should be capable of wider application than their direct bearing on the barrel-steel problem. The Government specifications for barrel steel for model 1903 rifle (Springfield) call for carbon 0.50 to 0.60 per cent., manganese 1.00 to 1.29 per cent., silicon under 0.25 per cent., sulfur under 0.06 per cent., phosphorus under 0.08. per cent. The minimum physical requirements are: Tensile strength,- 110,000 lb. per sq. in. (7733 kg. per sq. cm.); yield point, 75,000 lb. per sq. in (5472 kg. per sq. cm.); elongation, 20 per cent.; reduction of area, 45 per cent. Material fulfilling these requirement's gives practically no failures when proof-fired, with charge of 70,000 lb. per sq. in. pressure, which is 40 per cent. in excess of the service charge. The turning and drilling operations show up any seams or laps such as accidentally occur even in- the best heats of open-hearth steel, so that' faulty stock is practically all eliminated before proof-firing. These physical requirements are met either by rolling billets at, a proper temperature clown to the form of tapered barrel blanks or by heat-treating bars that have been upset to enlarge the breech section. The transformation temperature of this steel, on heating, is around 1350° F. (732° C.), varying somewhat with the composition and the rate of heating. The actual treatment of the barrel blanks, as carried out by different

Jan 7, 1919