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By Alfred V. de Forest

WE are now assembled in this hall for the eighteenth lecture in honor of the memory of our greatest American metallurgist, Henry Marion Howe. Many of his most intimate contemporaries, led, as was fitting, by Professor Sauveur, have described his vital accomplishments in three fields: as a leader in technical industrial development; in theoretical research; and finally as a teacher and source of inspiration for nearly two generations of students. In 1914 Professor Howe had retired from active teaching, but maintained his laboratory at Columbia University under the care of Arthur G. Levy, with whom he published many of the papers that later were incorporated into his last book, "The Metallography of Steel and Cast Iron." My position at the time was that of personal assistant to Professor Campbell-no pay, no duties, but the great privilege of preparing specimens, taking pictures and attending to some of the current consulting work. Whenever possible, I visited Howe's laboratory to chat with Levy and gather ideas about the wonderful field of metallography-in which I was a rank amateur, rescued by the quiet enthusiasm of Donald Smith of Princeton from an instructorship in civil engineering. Levy let me act as a fly on the wall during the Professor's occasional visits. Busy as he was, Professor Howe took the time and trouble to encourage my interest, as he had done for hundreds of others. He told me how he went about gathering his own information speculating as to causes, considering experiments, and verifying his conclusions. I ventured to mention some tests I had run on the irregular stretching of wires of different metals. He read the small volume I had prepared of ill-assorted facts and fancies and remarked: "Nobody cares for your theories or the history of your tests. Describe what you found as briefly as possible and perhaps I can help you to publish." Curiously enough, among my discards were some autographically recorded load-versus-electrical-resistance measurements. Taken with inadequate knowledge and equipment, these curves did not reproduce consistently, but if the relationship between strain and resistance had then been explored, the latest type of strain gauge might have been in useful service for the past 25 years. Professor Howe was a gifted teacher, perhaps because he was primarily an ardent and assiduous student. His own eagerness to learn and his willingness to revise and extend his opinions constantly encouraged those of his environment to be diligent and painstaking in the pursuit of knowledge. In honoring his memory, I also wish to bring to mind the kindly, humorous and quiet Levy, and join his name again, as it was for too brief a space in the past, with that of many-sided Henry Marion Howe. FACTORS OF IMPACT STRENGTH The subject chosen for the Howe Memorial Lecture by Dr. Gillett last year

Jan 1, 1941

By C. G. Grant, Wm. B. Price

This investigation of low copper-nickel silvers was untiertaken to check the work of Lèon Guillet on special brasses and to determine, more accurately, the effect of the addition of nickel on the mierostructure of the binary alloys of copper arid zinc. It was hoped that the results could be successfully applied to the practical production of low copper-nickel silvers. To explain the results of his investigations on special brasses, Lèon Guillet evolved his conception of "fictitious compositions." He states,' in his general conclusions, that on the introduction of a small amount of a third metal to a copper-zinc alloy, it enters into solid solution with the normal constituents up to saturation, but by so doing it brings the ternary alloy into a state microscopically equivalent to a binary copper-zinc alloy of fictitious composition, and physically more nearly like the latter than the brass containing copper-zinc in the ratio actually present. The physical properties of the ternary alloy, when compared to the same properties of an actual brass of the fictitious composition, are modified by the natural properties of the third element. Beyond the point of saturation, a special constituent appears and the above generalization no longer holds. For example, if a 60:40 brass has 4 per cent. of tin substituted for 4 per cent. of zinc, the actual composition would analyze 60:36:4. Assuming that 1 per cent. of tin plays the same part as 2 per cent. of zinc, the proportions of copper and equivalent zinc may be stated as 60 parts of copper and 44 parts of zinc, which, figured to 100 per cent., gives an analysis of 57.7 per cent. of copper and 42.3 per cent. of zinc, the fictitious composition for a 60:36:4 tin brass. The relation between ternary alloys containing copper and zinc together with a third metal, and the microscopically equivalent binary alloy of copper and zinc, may be expressed mathematically.

Jan 1, 1924

By Charles Prasky, Robert K. Zahl, John C. Nigro

Bench scale and pilot plant research was conducted using dolomitic (CaO - MgO) lime as the basic additive in the preparation of self-fluxed pellets from a typical magnetic taconite concentrate (5.5% SiO2). The specific objective of this investigation was to ascertain the viability of the magnesia lime pellets in high temperature oxidizing and reducing atmospheres. Pellet basicity and induration temperature were major parameters affecting fired pellet quality; temperatures ranging from 1200° to 1250°C appeared to be the most favorable for production of self-fluxed pellets with basicities (B) above 1.0. Comparison of the mechanical and metallurgical properties of regular (acid) and self-fluxed pellets (B = 1.55) produced under similar conditions in a modified grate pelletizing machine showed that the selffluxed pellets were more resistant to abrasion and to high and low temperature reduction disintegration, an important consideration in commercial application. The +3 mesh Linder index increased from 68% (regular pellets) to over 90% (self-fluxed pellets). The reducibility and swelling indices of the self-fluxed pellets were found to be comparable to the regular pellets.

Jan 1, 1974

By F. W. Newhall

DURING the latter part of the year 1931, the Republic mine of the Republic Steel Corporation, at Republic, about 4 miles south of Browns-ville, Pa., was mining coal along four rib or fracture lines. One of these lines, the west butt rib line, was retreating towards a concrete-lined air shaft, 320 ft. deep, which had been sunk in 1911 for ventilation purposes. With the normal rate of mining at that time, it was expected that this rib line would pass the shaft in three or four months and the shaft would then be abandoned and allowed to cave. Realizing the opportunity presented for the study of an unusual case of ground movement, the question of conducting the study was presented by the junior author to the chairman of the Institute's committee on Ground Movement and Subsidence, Mr. George S. Rice, who presented the matter to Mr. G. H. Morse, General Manager of the Northern Mines, Republic Steel Corpora-tion, and he agreed to cooperate with the Bureau of Mines in making the study, the results of which are presented in this paper. Acknowledg-ments are due to Mr. Morse for his full cooperation in this work and to Mr. G. S. Rice and Mr. J. W. Paul, both of the U. S. Bureau of Mines, for their advice and guidance during the course of the work. The authors are indebted to Mr. B. F. Herbert, mining engineer, Northern Coal Mines, Republic Steel Corporation, who assisted in all the surveys, and Mr. W. H. Smith, draftsman, U. S. Bureau of Mines, who prepared all illustrations for publication.

Jan 1, 1934

By G. A. Hellstrand

IN 1915, H. A. Guess, Vice President of American Smelting & Refining Co., in charge of its Mining Department, learned that the Anglo-New-foundland Development Co., Ltd., a pulpwood and paper-mill enterprise, had found upon its large concession in Newfoundland, and had opened up by shaft to the third level and some drifting, a lenticular orebody indicat-ing about 100,000 tons, as an extremely fine-grained sulfide ore, averaging about 0.05 oz. Au, 4 oz. Ag, 1.5 per cent Cu, 10 per cent Pb, 18 per cent Zn; and that having sent parcels of this ore to Minerals Separation, Ltd., and various other metallurgical testing concerns without obtaining any success in commercial separations thereon, had discontinued work thereon and let the workings fill. Mr. Guess wrote to the general manager of that company and obtained a few hundred pounds of the typical ore, which he sent to his company's metallurgical testing laboratory at Flat River, Mo., outlining various flotation tests desired thereon, in an endeavor to obtain separation into a commercial lead concentrate and a zinc concentrate. But the art of flotation had not then progressed far enough to treat such ore, the galena and zinc blende being so fine grained that grinding to about 300 mesh was required to release the mineral particles in their gangue. Mr. Guess had flotation and other tests continued upon this ore from time to time with whatever new reagents and flotation devices were evolved as time went on, and finally, in 1925, he succeeded in effecting in his company's testing plant, then at Wallace, Idaho, separations into lead concentrates and zinc concentrates of satisfactory commercial grade. Mr. Guess then proceeded to unwater, examine and sample the property and made with the owners a partnership operating agreement upon the mine itself and a considerable area surrounding it, and in the early summer of 1926 began to prospect for additional orebodies, utilizing for such prospecting geophysical methods, under the direction of Hans Lundberg, methods which up to that time had been little used in mining in the western hemisphere.. This geophysical work found two large flat-lying orebodies of a type precisely similar to the smaller body of the original discovery. The larger orebody, some 3500 ft. west of the original

Jan 1, 1934

By Kurt Stock

The grades of spelter demanded by the consuming industries were not definitely established until the American Society for Testing Materials undertook to fix specifications, based on the varying percentages of the common impurities (lead, iron, and cadmium) as follows: Total, Not Leap, Iron, Cadmium, Over. Per Per Cent. Per Cent. Per Cent. Cent. A. High grade.................. 0.07 0.03 0.05 0.10 B. Intermediate................ 0.20 0.03 0.50 0.50 C. Brass special................ 0.75 0.04 0.75 1.20 D. Prime western............... 1.50 0.08 The question which grade was the best for certain purposes and why was left unanswered. The conservatism of the zinc-smelting industry and the unwillingness of the spelter-consuming industries to engage in research work prevented the full benefits being obtained that such standardization promised. The custom smelters, producing spelter in pigs or plates, found it impossible to adhere closely to the established limits on account of the variety of ores treated; and the smelters with long-established and known brands, or those manufacturing their metal into marketable products, like sheet zinc, did not have to abide by the newly established grades based on chemical percentages. Smelters engaged in the smelting of custom ores had occasional complaints about the quality of their metal, as some of the consumers, especially brassmakers and some galvanizers, used the rigid standards of the A. S. T. M. as a basis for obtaining redress from zinc smelters whenever some of their work was faulty. Indirectly, much good resulted from such complaints; for while the brassmakers and galvanizers, on the whole, did not know what was wrong, the metallurgists in charge of zinc smelters were induced to abandon their conservatism and study the influence of impurities in spelter from the point of view of the consumer. For some of us, spelter gradually ceased to be considered merely spelter; it

Jan 1, 1925

By Leo F. Reinartz

Part III of a four-part series on the history of steelmaking in the US, describes furnace developments, improvements during the last few decades, and the contribution of the AIME. THE invention of the dolomite machine was a great boon to the open-hearth furnaceman. By speeding up bottom making, it helped to increase tons per hour and decrease cost. The first homemade unit was built and operated before 1925 at the South Side works of Jones & Laughlin Steel Corp., Pittsburgh The first commercial machine, similar to those known today, was built for the Donner Steel Co., Buffalo, N. Y., in 1925. Heavy slab buckstays, 6 in. by 15 in., supplanted lighter I-beam buckstays as furnace framework in the middle 1920's. They greatly improved the rigidity of the furnace binding. Although the first sloping back wall had been in- stalled prior to 1920 on a small basic open-hearth foundry furnace at Columbus, Ohio, the impetus to install such back walls universally in ingots shops came after S. Naismith installed the first one on an open-hearth furnace at Illinois Steel Company's South works in June 1924. Before that event, back- wall life had already been improved somewhat by the use of chrome rock or metal-encased basic brick. Here again, these changes heralded major for- ward steps in furnace design, decreased costs, in- creased production, and improved safety and working conditions on the back standing of the furnace. Fuels Up to 1930, a number of different kinds of fuel were used to melt and refine steel in American open hearth furnaces. During World War I, powdered coal was used in a few plants as an open-hearth fuel, but because of the high sulfur and ash content in the coals, many operational difficulties arose. There were also dust, explosion, and accident hazards, so that after the War its use was discontinued. In some steel-manufacturing centers, natural gas was available as a fuel and gave good performance. In most steel-manufacturing centers, operators had to rely on producer gas made from bituminous coals in producer gas houses. Low-sulfur low-ash, high-fusion coals required for the manufacture of such gas were not readily available. The quality of producer gas was uncertain. The gas had to be pre-heated. Maintenance problems connected with the use of this fuel were serious. Tons per hour per month was unsatisfactory. Although petroleum had been first discovered by Edwin L. Drake at Titusville, Pa., in 1859, it was not until the early 1930's that heavy fuel oil residues for open-hearth use began to appear on the market. They were cheap; the calorific value was high, and it was not necessary to pass this fuel through the checkers to preheat it. Various plants began to use such oil as an open-hearth fuel. Others used it in combinations with tar, coke-oven, and/or blast-furnace gases. Because of its low calorific value, blast-furnace gas had to be preheated in the checkers. These fuels were cleaner and more dependable than producer gas. The dirty gas house adjacent to the open-hearth shop was no longer needed, and

Jan 1, 1961

By C. P. Proctor, J. T. Crawford

TROUGH washers were among the earliest methods used for concentrating ores; they are referred to by Agricola about the middle of the sixteenth century as already being used while the hand- operated jigging sieve had only recently come into use. For cleaning coal the trough washer apparently was first used in France and Belgium about 1841. The early trough washers were intermittent and the refuse at least was shoveled out by hand. The invention of a continuous jig washer, by a Frenchman, Berard, in 1848, acted as a stimulus to coal washings in jigs and retarded progress in trough washing in the nineteenth century. Chapman and Mott' describe a number of trough washers developed in England and on the Continent from 1850 to 1900, such as the Bell and Ramsay, Ramsay, Bell and Green, Wunderlich, Scaife, McLellan, Lodge, Elliott, Blackett, and Murton. The later of these removed the refuse mechanically, either intermittently or continuously, but in ways that interfered with stratification.

Jan 1, 1943

By Frank H. Armstrong

All the mining machinery of the Penn Iron Mining Co. has been operated by electric power for several years and when another shovel for stockpile loading was required the advantages of an electric shovel were naturally considered. After considerable study, serious objections suggested themselves the use of a shovel operated directly by electrical apparatus by reason of the complicated control, severe service on the motors and the heavy surges of current required from the line. It was finally decided to construct an electro-hydraulic shovel using water under pressure to perform all the necessary operations except that of propelling, for which a separate motor was best suited. A car body with boom, dipper handle and dipper of late design, but without any of the steam machinery, was purchased. A motor-driven centrifugal pump, a pressure tank, an air tank, a small air compressor and water cylinders with plungers, pistons and valves, were installed in place of the steam equipment. Fig. 1 shows this shovel under construction and Fig. 2 shows it as it was operated during the first year, the summer of 1914. The large tank at the back of the car, in Fig. 1, carried air under

Jan 1, 1916

By Oliver Smalley

EXCEPT for the work of Guillet, who conducted a systematic investigation on the zinc-replacing value of nickel in brass, and extended his investigation with a view to developing commercial high zinc content nickel brasses, the author does not know of any systematic research on the subject. The most promising commercial alloys and their physical properties obtained by Guillet are given below: Maximum Elonga- Reduction Copper Zinc Nickel Stress, tion, of Area, Brinell Tons Per Per Cent. Per Cent. Sq. In. 55.0 41.0 5.0 24.4 46.5 94 Sand cast. 22.6 27.0 90 Chill cast. 56.7 39.74 3.35 30.0 43.0 51.7 97 Casting annealed 2 hr. at 750° C. 33.9 33.0 50.7 144 Cold-drawn bar. 55.15 42.3 2.24 29.8 33.0 116 Casting annealed 2 hr. at 750° C. 32.3 29.0 151 Cold-drawn bar. These test results scarcely justify the use of such quantities of so expensive a metal, and could have been obtained from ordinary commercial brass. For purposes of comparison, the physical properties of ordinary brasses, ranging from 70 per cent. to 50.1 per cent. Cu in both the cast and normalized1 conditions are included in Table 1. These incidentally furnish a useful standard of the properties of castings and of rolled, extruded and forged brass when correctly annealed. A close study of some of the well-known special brasses containing nickel reveals a series of alloys which bewilder by their complexity, and one can only hazard a guess at the function and commercial value of each of the many elements used.

Jan 10, 1925

By A. A. Smith, J. S. Smart

THE elements silver, cadmium, tin, antimony and tellurium either are found as impurities in commercial coppers or are intentionally added to produce coppers for special uses, When present in small quantities, each of these metals exerts a significant effect on the properties of copper, but despite considerable experience and investigation much remains to be learned about their specific behavior. The presence of extraneous elements, particularly oxygen, complicates the study of individual additions of impurities in the range 0 to 0.05 per cent, and the use of high-purity copper has been found extremely helpful in circumventing these difficulties. It has also been found that individual behavior can be satisfactorily determined from measurements of two commercially important properties, conductivity and softening temperature, according to methods that have been described previously.1,2 Data of this type, obtained in the course of a general investigation of the effects of impurities on the properties of both oxygen-bearing and oxygen-free copper are presented herewith. All samples except those containing cadmium were prepared as 3/8-in. continuously cast oxygen-free rod from pure copper and weighed amounts of a similarly synthesized master alloy. Composition was checked by chemical methods, which in every case verified the calculated analyses. Test wires were cold-drawn one B. and S. number per pass on a string-up machine using four 30-min. 600°C. anneals at 0.3125, 0.257, 0.204 and 0.162 in. and a final cold reduction of 75 per cent to 0.081 in. Some oxygen-bearing samples were produced directly from the 3/8-in. oxygen-free rods by diffusion from a surface scale at 850°C. and drawn to size as listed above, but most of the alloys were remelted in pure graphite and cast through air into a I-in. round mold, The slugs were then hot-rolled to 5/16 in., drawn to 0.162 in., annealed as listed above, and drawn to 0.081 inch. Conductivity wires were annealed for I hr. at 100°C. intervals between 300° and 800°F., using a hydrogen atmosphere for oxygen-free samples and purified nitrogen for the oxygen-bearing type, All samples were quenched from the annealing temperature in 10 per cent H2SO4 and conductivity was measured on a Hoopes bridge that had been checked against a Kelvin bridge. The softening temperatures represent the half-hard stage of the annealing curve as determined by a standard procedure.1 EFFECT OF SILVER Numerous excellent studies of the argentiferous coppers are found in the literature, and these have been adequately

Jan 1, 1943

By L. A. Willey, William L. Fink

TWO of the aluminum-alloy systems previously studied—the aluminum-titanium and the aluminum-chromium—exhibit a peritectic reaction at the extreme aluminum end of the diagram. Preliminary work indicated that the aluminum-zirconium and certain other aluminum systems were similar in this respect. The present paper, the twentieth of a series from the Aluminum Research Laboratories, reports the results of a recent investigation of equilibrium relations in aluminum-zirconium alloys of high purity, which confirm the preliminary observations. Previous Investigations There has been only one investigation of the aluminum end of the aluminum-zirconium system. Sykesl prepared and studied alloys containing 0 to 70 per cent Zr. The lowering of the freezing point of aluminum by the addition of zirconium was found to be very little, if any (less than 2" C.). He placed the solid solubility of zirconium in aluminum at room temperature between 0.57 and 0.97 per cent. A few other investigators have attempted to determine the composition of the intermetallic compounds occurring in this system. Honigschmid2 obtained the compound ZrAla as a by-product during the preparation of ZrSi2. He made no attempt to prepare other aluminum-zirconium compounds. Weiss and Newmann3 prepared an alloy by heating aluminum with a double fluoride of potassium and zirconium. When this alloy was treated consecutively with caustic soda and hydrochloric acid, there was a residue, which contained approximately 72 per cent Zr and 28 per cent A1 (Zr3AI4). Marden and Rich4 prepared an alloy in the same way, treated it with caustic soda, and obtained a residue of silver-white crystals, which contained 70 per cent Zr and 30 per cent A1 (Zr3A14). Alloys Materials Used.—Electrolytically refined aluminum was employed for thc preparation of all alloys used in this investigation. The chemical

Jan 1, 1939

By William L. Fink, L. A. Willey

TWO of the aluminum-alloy systems previously studied—the aluminum-titanium and the aluminum-chromium—exhibit a peritectic reaction at the extreme aluminum end of the diagram. Preliminary work indicated that the aluminum-zirconium and certain other aluminum systems were similar in this respect. The present paper, the twentieth of a series from the Aluminum Research Laboratories, reports the results of a recent investigation of equilibrium relations in aluminum-zirconium alloys of high purity, which confirm the preliminary observations. Previous Investigations There has been only one investigation of the aluminum end of the aluminum-zirconium system. Sykesl prepared and studied alloys containing 0 to 70 per cent Zr. The lowering of the freezing point of aluminum by the addition of zirconium was found to be very little, if any (less than 2" C.). He placed the solid solubility of zirconium in aluminum at room temperature between 0.57 and 0.97 per cent. A few other investigators have attempted to determine the composition of the intermetallic compounds occurring in this system. Honigschmid2 obtained the compound ZrAla as a by-product during the preparation of ZrSi2. He made no attempt to prepare other aluminum-zirconium compounds. Weiss and Newmann3 prepared an alloy by heating aluminum with a double fluoride of potassium and zirconium. When this alloy was treated consecutively with caustic soda and hydrochloric acid, there was a residue, which contained approximately 72 per cent Zr and 28 per cent A1 (Zr3AI4). Marden and Rich4 prepared an alloy in the same way, treated it with caustic soda, and obtained a residue of silver-white crystals, which contained 70 per cent Zr and 30 per cent A1 (Zr3A14). Alloys Materials Used.—Electrolytically refined aluminum was employed for thc preparation of all alloys used in this investigation. The chemical

Jan 1, 1939

By Charles R. Austin, Carl H. Samans

In an earlier serics of studies on 18-8 stainless steel at 600º, 700º, and 800ºC.l one pretreatment was used throughout; viz., 15 min. in hydrogen at 950°C., followed by an air quench. Several manufacturers of this alloy since have expressed doubt as to the suitability of the temperature employed, recommending instead the more customary Strauss treatment as promising superior results. In this subsequent investigation on the effects of the temperature of pretreatment several interesting points have arisen, which are described in this paper. Previous work on our equipment had shown a marked difference between alloys of "similar chemical composition" that had been manufactured by different companies. Accordingly, one mill-bar length was selected from which to prepare all specimens. It could then be assumed that any marked differences in creep characteristics would be due to effects resulting from variations in the pretreatment of the alloy. The material was furnished by the Allegheny-Ludlum Steel Co. in the form of 5/16-in. dia. rod, finished by air cooling from a mill anneal at 1950°F. (1066°C.). It was analyzed only for the elements shown: carbon, 0.07 per cent; chromium, 18.73; nickel, 9.46; manganese, 0.40. Three pretreating temperatures were chosen, the specimens being held for 15 min. in hydrogen at either: (1) 1150°C., to conform to the recommended Strauss treatment; (2) 950°C., to compare with the results of previous tests; or (3) 75Q°C., to initiate precipitation of carbides in the material before testing. As the test cross sections were only 1/8-in. dia., air cooling followed the annealing treatment. These treatments permitted two direct comparisons: (1) between the 1150" and 950°C. treatments to indicate the effect of grain size when all carbides were probably in solution at the start of the test; and (2) between the 950" and 750°C. treatments to indicate the effect of carbide "nucleation" for similar grain sizes.

Jan 1, 1940

By Carl H. Samans, Charles R. Austin

In an earlier serics of studies on 18-8 stainless steel at 600º, 700º, and 800ºC.l one pretreatment was used throughout; viz., 15 min. in hydrogen at 950°C., followed by an air quench. Several manufacturers of this alloy since have expressed doubt as to the suitability of the temperature employed, recommending instead the more customary Strauss treatment as promising superior results. In this subsequent investigation on the effects of the temperature of pretreatment several interesting points have arisen, which are described in this paper. Previous work on our equipment had shown a marked difference between alloys of "similar chemical composition" that had been manufactured by different companies. Accordingly, one mill-bar length was selected from which to prepare all specimens. It could then be assumed that any marked differences in creep characteristics would be due to effects resulting from variations in the pretreatment of the alloy. The material was furnished by the Allegheny-Ludlum Steel Co. in the form of 5/16-in. dia. rod, finished by air cooling from a mill anneal at 1950°F. (1066°C.). It was analyzed only for the elements shown: carbon, 0.07 per cent; chromium, 18.73; nickel, 9.46; manganese, 0.40. Three pretreating temperatures were chosen, the specimens being held for 15 min. in hydrogen at either: (1) 1150°C., to conform to the recommended Strauss treatment; (2) 950°C., to compare with the results of previous tests; or (3) 75Q°C., to initiate precipitation of carbides in the material before testing. As the test cross sections were only 1/8-in. dia., air cooling followed the annealing treatment. These treatments permitted two direct comparisons: (1) between the 1150" and 950°C. treatments to indicate the effect of grain size when all carbides were probably in solution at the start of the test; and (2) between the 950" and 750°C. treatments to indicate the effect of carbide "nucleation" for similar grain sizes.

Jan 1, 1940

By C. Upthegrove

DURING the past year considerable work dealing with physical properties of cartridge brass was done at the University of Michigan in cooperation with the Ordnance Department of the U. S. Army. This paper gives some of the data bearing on the effect of the anneal, previous to the final reduction or rolling, on the physical properties, particularly the hardness. Various phases of the subject of physical properties of cartridge brass have been presented by different investigators. Mathewson and Phillips1 refer to the work of Grard, in 1909, as the first systematic presentation of the relation between temperature-and time of anneal; changing of physical properties and microstructure, and the previous reduction by cold rolling. They discuss the relation between time and temperature of anneal and the previous reduction by cold rolling also; the relation between physical properties and grain size of annealed brass. The degree of deformation previous to the annealing was found to determine the temperature at which recrystallization and corresponding changes in physical properties would take place. Bassett and Davis,2 in establishing the relation between grain size and Brinell hardness; found the hardness for low-temperature annealing to be dependent on the previous degree of reduction, while for anneals above a certain temperature the hardness after the anneal was independent of the degree of reduction. Actual differences in hardness, due to the degree of reduction, disappear only on annealing at 600° C. or above; though the differences for metal subjected to different degrees of reduction and annealed at temperatures between 350° and 600° C. were found to be relatively small. In their determination of the relationship of grain size to Brinell hardness, Bassett

Jan 5, 1922

By V. R. Thompson, R. C. Westgren

In a recent paper,1 the solid-solution strengthening of tungsten and tantalum in a portion of the W-T;-MO-C~ alloy system was described. Additions of tantalum and columbium to tungsten led to significant strengthening, and the introduction of dispersions into these alloys was suggested as a means of further increasing strength. Dispersion strengthening of columbium and molybdenum alloys has been studied extensively.2-4 The approach used to dispersion-strengthen molybdenum alloys appeared equally suitable for tungsten alloys, and, therefore, a brief study was undertaken to determine to what extent the introduction of carbide dispersions would strengthen a solid-solution tungsten-base alloy. A base composition of tungsten and 10 to 12 pet Cb was selected; previous work1 had shown that the tensile strength of this solid-solution alloy was 50,000 psi at 3000°F. For the study of the effects of small additions of

Jan 1, 1964

By V. F. Swanson

A petrographic study was made of the type and sources of mineral contamination occurring in Florida phosphate rock products. Emphasis was placed on contaminants in the screened rock (+1 mm), since this portion of the product undergoes no physical beneficiation except for scrubbing to remove slimes. Since iron and aluminum contents of the finished product affect the salability, special emphasis was placed on identifying types and sources of these contaminants and relating chemical composition to visual characteristics. Wavellite derived from the overburden was the major aluminum contaminant with some aluminum being included as secondary clay balls. Iron occurred as phosphates in the overburden and as colloidal oxides included in the phosphate pebbles. Chert and limestone contamination derived from the Hawthorne formation underlying the phosphate matrix.

Jan 1, 1972

By Roy E. Thomas

Soon after the Waelz p1an.t for the fire concentration of low-grade zinc ores was put into operation in the early part of 1929 at Katowice, it was found that the conveyor equipment for transporting the hot residue from the furnace dust chambers was inadequate. Hand tramming with water cooling was used for a time, but that method was injurious to the workmen as well as costly. The problem was to find some practical mechanical means of conveying flue dust at temperatures of from 450" to 600°C. as it was drawn from the dust chambers. After considerable preliminary investigation it was decided to install pneumatic equipment for conveying the hot materials to a central mixing plant, where it would be mixed with slime and from which it would be returned to the furnace feed hoppers. The first pnenmatic equipment was installed in 1930, and has been in successful operation since that time. The pneumatic method of transportation has shown a considerable saving in operating costs over the former methods of dust handling and a decided improvement in working and hygienic conditions at the plant, through the elimination of the dust hazard. Additional pneumatic equipment mas installed in 1933 for conveying the furnace fume from the baghouses to the roaster plant. At the same time pick-up lines were provided for collecting the cleanings from the vertical and horizontal cooling pipes that are between the furnace dust chambers and the baghouses. The latter installation has practically eliminated a dusty and costly hand-tramming operation. A third extension was made to the pneumatic system in 1938 for conveying 'the zinc-lead-cadmium fume from the roaster-plant baghouses and flues to a new re-treatment plant for secondary products. The success of pneumatic conveying at the Waelz plant was the determining factor in the decision to install another pneumatic unit at the Saeger zinc-roasting and sintering plant. The new unit at Saeger was installed early in 1938 for the transportation of flue and Cottrell dust, small amounts of flotation concentrates to the sinter machines, and

Jan 1, 1944

By V. Annamalai, J. B. Hiskey

Abstract-The kinetics of copper cementation on a rotating disc of pure aluminum were studied as a function of chloride ion concentration, rotational speed of the aluminum disc, hydrogen ion concentration, copper ion concentration, and temperature. The optimum experimental conditions for all the parameters were determined. Chloride ion was found to destroy the naturally existing aluminum oxide film, and enabled the cementation reaction to proceed. A two-step rate, observed in most of the experiments, was attributed to the attainment of a roughened surface. An Evans diagram for the copper-pure aluminum system was constructed and utilized in predicting the controlling mechanism of the system. At low temperatures (<33°C), the rate with an experimental activation energy of 20.36 kcal mol-1 was controlled by the presence of an oxide layer. While at higher temperatures presence of an oxide layer. While at higher temperatures (>33° mol-1 was controlled by ionic diffusion. The deposits obtained were pure copper and not a copper-aluminum alloy. The amount of aluminum dissolved was determined for each experiment, and the maximum excess consumption was found to be only 40%. The structural characteristics of the copper deposits were studied using a scanning electron microscope. These observations indicated that the deposits were either bulbous, massive crystalline, or dendrites of different degrees of fineness depending on the experimental variables. The reaction rates seemed to depend on the deposit structures in a predictable way when a particular experimental parameter was varied.

Jan 6, 1978