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By R. S. Handy

THE properties of the Patiño Mines and Enterprises Consolidated, Inc., a New York corporation, are near Llallagua in the department of Chayanta in the west central part of Bolivia, South America, about 80 miles southeast of Oruro and 250 miles southeast of La Paz, the largest city in Bolivia and its virtual capital. The properties are accessible by railroad from three points on the west coast-from Mollendo, Peru, across Lake Titicaca, from Arica by way of La Paz, and from Antofagasta, Chile. The latter route, although the longest, is recommended by the companies as affording a more gradual introduction to the high altitudes; the mine being 13,000 ft. above sea level. The company operates its own railroad from its properties at Uncia to Machacamarca on the Chile & Bolivia R. R., a distance of 60 miles. This railroad is well equipped and well operated, and its location among the mountains surrounding Uncia represents excellent engineering skill. In fact all of the railroads, although they are of only a meter gage, are remarkable for the excellence of their construction, the arrangement of their dining and sleeping cars and the precision of their operation. There is only one drawback to rail- road and hotel accommodations and that is the absence of heating facilities, which does not seem to affect the natives but keeps a tenderfoot's teeth chattering continually. The company is a consolidation of the Patiño company, owning properties at Uncia, with the Compafiia Estanfera de Llallagua, a' Chilean corporation owning contiguous properties at Llallagua. Before the consolidation these companies were deadly enemies, and there still remain at the surface plant at Uncia the fortifications and underground defences provided during the warfare between the two factions. Also, in the Azul, or "Blue" tunnel at the junction line between the two properties is a strong steel barricade still bearing marks of the bullets fired during the various armed tilts between the workmen of the two companies. The headquarters for the mining operations and the milling plant have been moved since the consolidation from the original location at Uncia to the Llallagua side of the mountain, where the Chilean company's operations were carried on. The historic old town of Uncia, with its massive stone buildings of Spanish design, is a wreck, while the Llallagua side is being rapidly built up with modern structures.

Jan 1, 1929

By Nicholas J. Grant, H. C. Chang

TRANSCRYSTALLINE fracture surfaces of the cleavage type have been examined by microscopy and X-rays for several metals.' These investigations revealed that the fractured surfaces were not flat and invariably had cleavage and other deformation markings on them. On the other hand, the study of inter crystalline fracture surfaces has been limited. Perryman, in a recently published paper on the inter crystalline fracture of ß-brasses,' found that a thin layer of heavily deformed metal was invariably associated with these surfaces. Furthermore, the thickness of this layer was found to depend on the orientation of the grain boundary surface with respect to the applied stress. The mechanisms of grain boundary sliding and intercrystalline fracture have been presented in two previous papers,which described certain aspects of the deformation of a 20 pct Zn-A1 alloy. It is the purpose of this paper to present some observations on the structure of intercrystalline fracture surfaces and to correlate the structure of such surfaces with the mechanism of intercrystalline fracture. Experimental Techniques—The high purity 20 pct Zn-Al alloy was generously supplied by the Research Laboratories of the Aluminum Co. of America. Two sizes of specimen were used; the first had two parallel flat surfaces of dimensions 1x0.17x0.09 in. and the second was round with a 0.25 in. diam. A grain diameter of 1 to 3 mm was obtained by annealing the specimens at 1000°F for 24 hr. The specimens were then air cooled. The specimens were subjected to creep at 500°F and 2300 psi. The rupture times ranged from % to 3 hr, with one room temperature tensile test. It has been mentioned previous1y" that the intercrystalline fracture surfaces of this alloy, when tested under the conditions given above, are sharply defined. In the optical examination of the fracture surfaces, whenever possible, magnifications of at least X250 were used. The locations of the regions examined, both optically and by X-rays, were selected to give several fracture surface orientations with respect to the stress axis and to the specimen surfaces. This was possible for the X-ray studies since the grain diameters were large compared to the X-ray beam. A film to specimen distance of 3 cm, a 1 mm pinhole and Cr radiation were used for the Laue back reflection pictures.

Jan 1, 1957

By J. Parke Channing

The Miami orebody occurs in an altered Pinal schist. It is popularly known as one of the '(porphyry " deposits but, as at Inspiration and Ray, the ore is an altered mincralized Pinal schist. The orebody mined is the zone of secondary enrichment. Speaking in general terms, the area of the orebody at Miami may be considered as 1000 ft. long and 800 ft. wide. The vertical thickness varies from 200 to 400 ft., so that it is an extremely irregular mass. The study of the ground movement and resulting subsidence at Miami is complicated by the fact that the formation is not homogeneous throughout the mining area, the orebody terminating on its eastern extremity at a fault plane adjoining the Gila conglomerate. This conglomerate is a recent sedimentary deposit somewhat analogous to glacial drift and consists of boulders of granite, schist, and other material cemented with clay, and at times is quite hard. The fault dips eastward at an angle of 45". The original method of mining was top slicing, the slices being 10 ft. thick. At first, there was a good deal of experimenting with mining methods. Some undercut rooms were tried, and the stopes were filled with broken ore with the idea of removing intervening pillars by top slicing. The adoption of the top-slicing method in itself involved considerable experimenting, including some experiments with a long-wall system. The method finally adopted involved the operation of top slicing areas 250 ft. square, each with a central supply raise and ore-gathering raises, each block being worked as a unit. Mining operations in the Captain orebody, which connects with the boundary of the Inspiration property, were started by the room-and-pillar system, the rooms extending across the orebody, with widths of 10 to 15 ft., with 15- to 10-ft. pillars between. The intent was to operate the rooms as shrinkage stopes, permitting the pillars to crush when the ore was drawn from the rooms. It was found that the shrinkage stoping was unnecessary, so a system of block caving was adopted. This system was so successful in the Captain orebody that, about three years ago, the method of mining in the orebody was changed from top slicing to block caving, the method now in use. The block caving system, as practiced

Jan 1, 1923

By J. Parke Channing

The Miami orebody occurs in an altered Pinal schist. It is popularly known as one of the '(porphyry " deposits but, as at Inspiration and Ray, the ore is an altered mincralized Pinal schist. The orebody mined is the zone of secondary enrichment. Speaking in general terms, the area of the orebody at Miami may be considered as 1000 ft. long and 800 ft. wide. The vertical thickness varies from 200 to 400 ft., so that it is an extremely irregular mass. The study of the ground movement and resulting subsidence at Miami is complicated by the fact that the formation is not homogeneous throughout the mining area, the orebody terminating on its eastern extremity at a fault plane adjoining the Gila conglomerate. This conglomerate is a recent sedimentary deposit somewhat analogous to glacial drift and consists of boulders of granite, schist, and other material cemented with clay, and at times is quite hard. The fault dips eastward at an angle of 45". The original method of mining was top slicing, the slices being 10 ft. thick. At first, there was a good deal of experimenting with mining methods. Some undercut rooms were tried, and the stopes were filled with broken ore with the idea of removing intervening pillars by top slicing. The adoption of the top-slicing method in itself involved considerable experimenting, including some experiments with a long-wall system. The method finally adopted involved the operation of top slicing areas 250 ft. square, each with a central supply raise and ore-gathering raises, each block being worked as a unit. Mining operations in the Captain orebody, which connects with the boundary of the Inspiration property, were started by the room-and-pillar system, the rooms extending across the orebody, with widths of 10 to 15 ft., with 15- to 10-ft. pillars between. The intent was to operate the rooms as shrinkage stopes, permitting the pillars to crush when the ore was drawn from the rooms. It was found that the shrinkage stoping was unnecessary, so a system of block caving was adopted. This system was so successful in the Captain orebody that, about three years ago, the method of mining in the orebody was changed from top slicing to block caving, the method now in use. The block caving system, as practiced

Jan 1, 1923

By E. G. Dean

A method of top slicing has been devised at the Miami Copper Co.'s mine at Miami, Aria., which differs radically in some ways from the customary methods of top slicing. The area of that section of the orebody in which top slicing is used is about 800 ft. square. The ore, while for the most part soft, is, nevertheless, considerably harder than the capping. The latter is siliceous, seldom containing any clay or other binding material, and breaks into fine particles so that it runs like sand if given the opportunity. Because of these facts, and because the ore is above the average grade of the mine ore, it has been mined by top slicing. Haulage levels are opened up 150 ft. apart, vertically, with two sub-levels between at 50-ft. intervals, to facilitate the putting up of ore chutes. These sublevels are used during slicing for distributing air in the ventilation system. On the haulage level the drifts are spaced on 50-ft. centers, and raises along these drifts are also spaced on 50-ft. centers, except the incline raises as hereafter noted. The raises are cribbed where necessary. Where the wear will be excessive, 1/4-in. iron plates are spiked to the top of every third set of cribbing, for its protection. When top slicing was first used, an attempt was made to carry a slicing face from fifty to several hundred feet long. Timber and other supplies were brought in through long drifts from an auxiliary shaft. Great difficulty was experienced in keeping these drifts open, the side pressure breaking the posts and the top weight breaking both caps and posts. Furthermore, the men could not work efficiently while these drifts were being repaired. The slicing faces advanced irregularly, due to varying conditions, and in many ways the results were not all that could be desired. It was then decided to divide the slicing area into blocks 200 ft. square and this was later changed to 250 ft. square. At the center of each block a two-compartment raise is put up as a supply raise, the compartments being 2 ft. 6 in. and 4 ft. by 4 ft. 4 in., the smaller being used as a manway. Station sets of 12 by 12 timber with

Jan 1, 1917

By Charles Legrand

In many iron, coal and copper mines where large tonnages are known before starting operation and proper provisions can be made, the problems of electric traction by trolley locomotives are not very different from those of surface plants. In such installations the gauge of the track, the radius of curves, and the clearances, both vertical and horizontal, can be made to suit the conditions of the traffic. It is more difficult to install electric traction in mines which were started with hand tramming and where no consideration was given to the possibility of mechanical traction being used. The writer having had some experience in the installation of electric traction in copper mines, the following remarks apply more particularly to these mines. With the gauge of track usually 18 or 20 in., the weight limit of locomotives obtainable from manufacturers in this country varies from 3 to 6 tons. The full-load speed varies from 49 to 6 miles per hour. These locomotives, being made to run on very small radius curves, have a short wheel base and a long overhang from axle to coupling, which necessitates a coupling' with a good deal of lateral motion to avoid derailing the cars on sharp curves, especially if couplings are of the standard railroad automatic type. Although 3-ton locomotives will run on 12- or 16-lb. rails, it has been found more satisfactory to use 25-lb. rails, as the track keeps in much better shape, it is easier to maintain the bonding in good order, and fewer derailments from dirt on the track occur with the larger rails. Where 6-ton locomotives are used the 25-lb. rails are satisfactory, but 40-lb. rails have proved cheaper where the traffic is heavy and the ground is soft, as the track maintenance is considerably lower with the heavy rails. The locomotives will run on 15-ft. radius curves, but on through runs it is advisable not to go below 40-ft. radius. The voltage used should not exceed 250 to 275 volts, and the trolley wire should be protected, to prevent accidental contacts, in front of chutes and at all points where it is low. With the air lacking somewhat in oxygen and the heat and high humidity prevalent in many mines, this

Jan 1, 1915

By A. H. Bell

The results of repressuring (or gas-drive) have been very encouraging to the several companies doing experimental work along these lines in California. The most notable examples are the Shell and the Union Oil companies at Dominguez, the Marland Oil Co. at Seal Beach, and the California Petroleum Corpn. at South Mountain. The results of the Marland test at Seal Beach are interesting in that re pressuring was started while several wells were still flowing; also, on account of the high pressures required to overcome the hydrostatic pressure exerted by high-head edge water. The well first chosen for repressuring is about halfway up the flank of the structure and had been on the beam making about 250 bbl. of fluid daily, cutting about 60 per cent. emulsion. The fluid lcvel was 230 ft. from the surface and the top of the sand was 4393 ft. Tubing was run to 4000 ft. with a packer and the space above the packer was filled with water to balance the high pressures. Gas was started in slowly to allow the fluid to be pushed back into the sand, and required three days at a pressure of 1500 Ib. per sq. in. before starting into formation. The pressure was once built up to 1800 Ib. and the compressor was shut down for a few hours. When again started, the well took gas at 1500 Ib., and after about three weeks the pressure was dropped to 1450 Ib. The present pressures required range between 1400 and 1450 lb. Volumes as high as 1,500,000 cu. ft. per 24 hr. were put into the well. Increases as high as 50 per cent. in production were obtained in wells up-structure with very little increase in wells down-structure. Also, the water cut on one edge well materially decreased. After about 40 days the repressuring was moved to two wells farther down-structure and the well originally repressured was put on production. The result of this was a great increase in the production of wells one location farther down-structure, a rapid increase in one well one location up-structure, and a decrease in production of the wells farthest up-structure. Later the gas started to short-cut to the nearest well down-structure, nullifying to a certain extent the effects of the repressuring work. The increased production that could be definitely attributed to the repressuring work

Jan 1, 1928

By E. T. Dumble

Discussion of the paper of E. T. DUMBLE, presented at the San Francisco meeting, September, 1915, and printed in Bulletin No. 104, August, 1915, pp. .1623 to 1638. E. L. DEGOLYER, Norman, Okla. (communIcatIon to the Secretary*).-Referring to Mr. Dumble's description of the stratigraphy of eastern Mexico, I should like to question the classification of the ?Papagallos? or ?Mendez? shales as being of Cretaceous age and the so-called overlapping of the Papagallos or Mendez shales by the Alazan shales; the classification of the San Felipe series as Cretaceous, and the correlation of the San Felipe series with the San Juan limestones. Mr. Durable apparently recognizes the continuity of the great shale formation by his use of the terms "Papagallos" and "Mendez," as equivalent and interchangeable, since the Papagallos Hills in the State of Nuevo Leon and Mendez Station in Northern Vera Cruz, localities at which the shale formation outcrops, and from which the formation names are taken, are approximately 250 miles apart and on opposite sides of the Tamaulipas barrier. The Papagallos shales (evidently referring here to the northern extension only) are said to be non-fossiliferous and no reason for .their Cretaceous classification is given, though in a previous article' they are classified as Cretaceous because at their northernmost outcrop they "have the same relation toward the overlying Tertiary that the Escondido (Cretaceous) has through its whole extent." The Alazan fossil locality was found by me and the first collections from it were sent to Dr. Dall; about 17 species of marine invertebrates were recognized by him, the fauna noted as having a distinct Pacific tincture, and the age of the formation from which they cause pronounced lower Eocene. The outcrop of the shale formation has been traced continuously from this point by me and my assistants into the Panuco River region, where Eocene fossils are reported at a depth of 1,810 ft. in a well at Topila.2 From Topila the formation has been traced continuously north to the Padilla-Jiminez region in Central Tamaulipas. Lithologically, the formation is fairly constant and though I am only generally acquainted with it north of the Padilla-Jiminez region, until definite evidence of the Cretaceous age of the Papagallos shale in its type localities, or of an overlap, is available, it seems to me more logical to consider the shale formation a single stratigraphic unit of Eocene age.

Jan 12, 1915

By D. E. Furman

The thermal coefficients of linear expansion for several stainless steels have been determined over the temperature range from —300° to 1000°F. The steels studied include types 301, 304, 316, 347, 310 and 330. This wide selection of compositions allows an insight into the effects of austenite stability and alloy content on the expansion characteristics. THE recent increased use of materials in low temperature applications has created a field for which the properties of austenitic iron, chromium, nickel alloys are particularly suited. Tensile and impact values of stainless steels at subzero temperatures have been made available in the technical literature but, as yet, little information has been published with respect to expansion characteristics. In order to supply this need, a study was made of several of the more common compositions. Those selected were types 301, 304, 316, 347, 310 and 330 stainless steel. Both the mean and instantaneous coefficients of linear expansion were determined over the temperature range from —300°F to 1000°F. Procedure The materials used were commercial grades with the exception of type 301 which was made in a 10# high frequency furnace. The compositions are listed in table I. All steels were given an anneal at 1950°F for 30 min and water quenched prior to machining the expansion specimens. Expansion readings were taken on specimens 0.250 in. in diam by 4.000 in. long with a fused quartz tube expansion apparatus similar to that described by Hidnert and Souder.1 Temperature measurements were made with a chromel-alurnel thermocouple calibrated for use at subzero temperatures. A bath of propane was used for temperatures from —300° to —100°F and one of alcohol from —100°F to room temperature. These baths were contained in large mouthed Dewar flasks and cooled to the desired temperature levels by passing liquid nitrogen through glass cooling coils placed in the flasks. The baths were stirred constantly for temperature equalization and were heated by immersing metal rods which were replaced frequently enough to give a heating rate of approximately 150°F per hr. A resistance wound furnace was used for heating from room temperature to 1000°F and throughout this range rates of about 450°F per hr were maintained. The furnace was designed so that the temperature gradient over the specimen was within 5°F. In most instances, the expansion readings were taken during heating from —300° to +300°F at

Jan 1, 1951

By Basil B. Zavoico

The production of all Russian fields incressed from approsimatctly 74,000,000 bbl. during 1926-27, to approximately 83,000,000 bbl. during 1927-28. Of this amount Baku was responsible for 54,.500,000 bbl., Grozny for 25,800,000 bbl., and Emba for 1,200,000 bbl. Accordingly, the proportional importance of the Grozny oil field has been considerably increased, the present production being twice that of 1913. The most notable factor of production during 1927-28 was the importance of gushers; 40.8 per cent. of the total was thus obtained. In the Baku fields 26 per cent. of the total, and in Grozny 74.2 percent'. of the total were produced by naturally flowing wells. This may be explained by the reduction in authorizations for drilling by the central authorities, and, accordingly, the local trusts increased the production to the planned figures at the expense of the proved prolific reserves. In Baku region, the Surnkany oil field produced 36.1 per cent. of the total Baku production, or an equivalent of 53,800 bbl. per clay, the largest percentage coining from the fifth horizon. Nest year's plans call for continual development of that horizon as well as of the sixteenth horizon in the Bibi-Eibat field, which was opened lately. In the Grozny fields the New Area (Bellik) WAS responsible for 79.4 per cent. of the total production. The authorized plan for 1928-29 production calls for 92,200,000 bid., and a reasonably accurate estimate for 1932--33 production is placed at. 156,000,000 bbl., with Baku contributing 101,800,000 bbl., Grozny 44,100,000 bbl., Emba 6,200,000 bbl., Kuban 2,100,000 bbl., Saghalien Island 1,400,000 bbl., and Russian Turkestan 400,000 bbl. In connection with recent discoverices in the Baku area these figures art. quite conservative. The average production per well per day in the Baku oil fields was 49.2 bbl., in Grozny 175 bbl.; in detail, Surakany oil field averaged 250 bbl., and the New Area in Grozny 514 bbl. per day. New completions in all Baku fields averaged 264 bbl. per day, and in Grozny 970 bbl. pel. day. These figures show a considerable progress in the technical developnlent of all fields, compared even with the prerevolution figures, since all the mprovements are noted in the fields that arc over 30 years old.

Jan 1, 1929

By J. Parke Channing

THE production and use of copper in the world, like that of other metals, has been of slow growth. In 1880, production in the United States, was only about 60,000,000 lb. and the world's production 325,000,000 lb. Up to 1913 there was a gradual and regular increase in production; in 1912 the production was 1,250,000,000 lb. for the United States and 2,200,-000,000 lb. for the world. At the outbreak of the war there was a slight falling off, both in the United States and elsewhere, but when it was realized that the war was not to be a short one and that copper was one of the most important things for carrying it on, there was a tremendous increase in production every-where. Roughly speaking, the average production for the years 1916, 1917 and 1918 was very close to two billion pounds in the United States and three billion pounds in the world. WAR DEMANDS STIMULATED PRODUCTION Not only did the production of copper in the United States increase, but the same may be said of .all the base metals, particularly of zinc. Much of the zinc used by the Allies came from Australia, but had been smelted in Belgium and Germany, now closed to them. We were called upon to make good this lost supply and in feverish haste built new zinc smelteries and opened new mines. The armistice found the United States with a large surplus of copper on hand, variously estimated at from 800,000,000 to 1,000,000,000 lb. In addition to this surplus in the United States, there were considerable stocks in the hands of the Allies and also immense quantities of unused brass. To. complicate the situa-tion still further, the reclamation of old brass shell cases and other used material was instituted, still further curtailing the demand for new material. This situation was- not appreciated at the time and it was assumed, that the Central Powers would immediately come into the market ? replenish their exhausted stock of copper. During the war Germany had torn down copper trolley wires and roofs, and melted up bronze bells, doors, statues and other copper-bearing material to reclaim this metal for military purposes. But Germany-was unable or at least unwilling immediately to replace her copper substitutes.

Jan 1, 1923

By A. E. Bellis

THE CHAIRMAN (ALBERT SAUVEUR, Cambridge, Mass.).-Any information likely to throw light on the constitution and proper treatment of high-speed steel in order to obtain maximum results, should surely he welcomed. All users of high-speed steel, I believe, will agree with the authors that, in order to obtain satisfactory results, it is not sufficient to heat all brands of high-speed steel to one and the same temperature; apparently very slight differences of chemical composition seem to call for marked differences in temperature. I think that all of us agree that a properly treated piece of high-speed steel should have a fine austenitic or polyhedral structure and that an appreciable quantity of free carbide may be present in the case of very high tungsten steels. What we seem to lack is a satisfactory method, quick and reliable, of ascertaining when the proper structure has been obtained. I think Mr. Bellis' paper is a step in the right direction. To the untrained eye, however, it is not an easy matter to select from some of his photomicrographs the one representing the best structure; for instance, in the case of steel A, we wonder why temperatures of 2,250 and 2,300 do not yield the same results, seeing that both structures are apparently alike, and the same might apply to some of the other samples. I have no doubt, however, that the experienced observer is capable of detecting structural differences that are not made plain here and by which he is able to select the proper quenching temperature. COLIN G. FINK, East Orange, N. J.-On page 68 the authors say that the use of a barium chloride bath to eliminate this difficulty has the disadvantage that the surface of the tool becomes decarbonized." I would like to ask whether they actually found that the surface was decarbonized, or whether they base this conclusion on softening alone? A. E. BELLIS, Springfield, Mass.-No, we have never demonstrated that it was a decarbonization, it is just the softening of the steel. The addition of ferrocyanide to the ferrochloride bath has been suggested. I think that is not altogether satisfactory, because the ferrocyanide bath changes composition very rapidly at these high temperatures, and it would be just a question of luck whether or not it had too much or too little ferrocyanide in the bath giving equilibrium with the carbon content.

Jan 4, 1917

By Louis A. Carapella, William E. Shaw

MAGNESIUM and its alloys have long been characterized as possessing limited capacity for mechanical forming at atmospheric temperatures prior to rupturing despite their outstanding performances in this respect at elevated temperatures. Responsible for this behavior are the fundamental facts that these hexagonal-type metals have comparatively few slip elements at low temperatures for any extensive deformation and that, at high temperatures, additional slip elements become operative, thus enhancing greater plasticity under strain. The transitional point has been set at 225°C by Schmid1 for single crystals, and at 250°°C by Morell and Hanawalt2 for extruded magnesium metal. In a recent X-ray investigation on polycrystalline magnesium-alloy sheets, Barrett and Haller3 have revealed that, below the transitional temperature, the initial plastic deformation proceeds mostly by a twinning action; that, above such a temperature, the action is mostly by slip. The deep-drawing performance of the magnesium + 1.5 pct alloy sheett over a wide range of temperatures has been investigated by Weber and Vanden Berg,' and their results are presented in Fig r. It should be noted from this work that a maximum drawability of about 25 pct at room temperature has been obtained on this alloy under the conventional deep-drawing operations. For the same alloy, it is now possible to augment the cold drawability to about 40 pct by a process to be disclosed. Hitherto, this value has been obtained only by deep-drawing the alloy at around 230°C. That greater plastic flow is attainable at atmospheric temperatures on magnesium under certain deformational techniques was discovered by the authors6 in their analyses of plastic-deformational behaviors of pure magnesium. This fact is best illustrated in Fig 2 from the Hargreaves analysis6 performed by the authors under two different modes of loading. For direct test, a separate unstrained specimen was used for each load duration, whereas for the integrated test the same specimen was employed for all the five intermittent loadings so that the load duration was made additive throughout the investigation. The higher plastic flow-rate at room temperature, as designated by the Hargreaves constant S, was obtained by the integrated or intermittent loading procedure. The authors5 in further tests showed that, under such a procedure greater plastic flow was also realized with a progressive increase in deformational loads. These findings have been applied

Jan 1, 1947

By Louis A. Carapella, William E. Shaw

Magnesium and its alloys have long been characterized as possessing limited capacity for mechanical forming at atmospheric temperatures prior to rupturing despite their outstanding performances in this respect at elevated temperatures. Responsible for this behavior are the fundamental facts that these hexagonal-type metals have comparatively few slip elements at low temperatures for any extensive deformation and that, at high temperatures, additional slip elements become operative, thus enhancing greater plasticity under strain. The transitionai point has been set at 2 25°C by Schmidl for single crystals, and at 250°C by Morel1 and Hanawalt² for extruded magnesium metal. In a recent X-ray investigation on poly-crystalline magnesium-alloy sheets, Barrett and Haller3 have revealed that, below the transitional tempelature, the initial plastic deformation proceeds mostly by a twinning action; that, above such a temperature, the action is mostly by slip. The deep-drawing performance of the magnesium + 1.5 pct alloy sheet† over a wide range of temperatures has been investigated by Weber and Vanden Berg,' and their results are presented in Fig I. It should be noted from this work that a maximum drawability of about 25 pct at room temperature has been obtained on this alloy under the conventional deep-drawing operations. For the same alloy, it is now possible to augment the cold drawability to about 40 pct by a process to be disclosed. Hitherto, this value has been obtained only by deep-drawing the alloy at around 230°C. That greater plastic flow is attainable at atmospheric temperatures on magnesium under certain deformational techniques was discovered by the authors6 in their analyses of plastic-deformational behaviors of pure magnesium. This fact is best illustrated in Fig 2 from the Har-greaves analysis6 performed by the authors under two different modes of loading. For direct test, a separate unstrained specimen was used for each load duration, whereas for the integrated test the same specimen was employed for all the five intermittent loadings so that the load duration was made additive throughout the investigation. The higher plastic flow-rate at room temperature, as designated by the Har-greaves constant S, was obtained by the integrated or intermittent loading procedure. The authors6 in further tests showed that, under such a procedure greater plastic flow was also realized with a progressive increase in deformatione 1 loads. These findings have been applicd

Jan 1, 1947

By William E. Shaw, Louis A. Carapella

Magnesium and its alloys have long been characterized as possessing limited capacity for mechanical forming at atmospheric temperatures prior to rupturing despite their outstanding performances in this respect at elevated temperatures. Responsible for this behavior are the fundamental facts that these hexagonal-type metals have comparatively few slip elements at low temperatures for any extensive deformation and that, at high temperatures, additional slip elements become operative, thus enhancing greater plasticity under strain. The transitionai point has been set at 2 25°C by Schmidl for single crystals, and at 250°C by Morel1 and Hanawalt² for extruded magnesium metal. In a recent X-ray investigation on poly-crystalline magnesium-alloy sheets, Barrett and Haller3 have revealed that, below the transitional tempelature, the initial plastic deformation proceeds mostly by a twinning action; that, above such a temperature, the action is mostly by slip. The deep-drawing performance of the magnesium + 1.5 pct alloy sheet† over a wide range of temperatures has been investigated by Weber and Vanden Berg,' and their results are presented in Fig I. It should be noted from this work that a maximum drawability of about 25 pct at room temperature has been obtained on this alloy under the conventional deep-drawing operations. For the same alloy, it is now possible to augment the cold drawability to about 40 pct by a process to be disclosed. Hitherto, this value has been obtained only by deep-drawing the alloy at around 230°C. That greater plastic flow is attainable at atmospheric temperatures on magnesium under certain deformational techniques was discovered by the authors6 in their analyses of plastic-deformational behaviors of pure magnesium. This fact is best illustrated in Fig 2 from the Har-greaves analysis6 performed by the authors under two different modes of loading. For direct test, a separate unstrained specimen was used for each load duration, whereas for the integrated test the same specimen was employed for all the five intermittent loadings so that the load duration was made additive throughout the investigation. The higher plastic flow-rate at room temperature, as designated by the Har-greaves constant S, was obtained by the integrated or intermittent loading procedure. The authors6 in further tests showed that, under such a procedure greater plastic flow was also realized with a progressive increase in deformatione 1 loads. These findings have been applicd

Jan 1, 1947

By James H. Bechtold

The yield strength of annealed tungsten was found to have a strain rate exponent 12 times as great as that of low carbon steel. The effects of temperature and strain rate could be correlated through the Zener-Hollomon parameter with a heat of activation associated with yielding of 32,000 cal per g-atom. This heat of activation is independent of strain although both the temperature and strain rate dependence of the yield strength vary with strain. MOST metals have mechanical properties that are relatively insensitive to strain rate, especially at temperatures below that at which creep is important. In iron and molybdenum," however, relatively large strain rate effects are observed in the temperature range where the rapid increase in yield strength occurs which leads to the ductile to brittle transition. In this temperature range Zener and Hollomon' have suggested that the effects of strain rate and temperature T on the yield strength could be correlated through a single parameter, P, in the following manner where Q is a heat of activation characteristic of the metal and associated with some unspecified relaxation process. They also observed that if the temperature is restricted to a relatively narrow range— below room temperature for steel—that the logarithm of the yield strength could be expressed as a linear function of the logarithm of P. From this relation the logarithm of stress should be a linear function of the logarithm of the strain rate at constant temperature: where r will be referred to herein as the strain rate exponent. At a constant strain rate the logarithm of stress should be a linear function of l/T, ay(e = C) ~ eT [4] where q = Qr [5] and is referred to herein as the temperature exponent. These equations have been found to relate the effects of temperature and strain rate on the yield strength of molybdenum in the temperature range wherein the ductile to brittle transition occurs, —75° to +150°C.2 Bechtold and Shewmon3 have shown recently that the ductile to brittle transition in annealed tungsten occurs in the temperature range +150° to +350°C. In this temperature range the yield strength in-

Jan 1, 1957

Pulverized Fuel Combustion The apparatus shown in the illustration is a complete equipment f r supplying coal to boiler and metallurgical furnaces, cement and lime kilns, dryers, and to all furnaces requiring a temperature and quality of fame under prompt and easy control. It is claimed that the Aero Pulverizer makes practicable the highest efficiency obtainable from burning coal. It makes coal burn like a gas, a flame, the physical and chemical character of which is regulable- a flame that may be elongated or shortened, thus placing the zone of highest temperature where needed- a flame that may be made oxidizing, reducing, or neutral, as occasion may require. The coal is burned as pulverized, and there is no storage of the powder with its attendant hazard. Artificial drying before pulverizing is not necessary if the coal supply be sheltered from rain and snow. Where the Aero is used, it is wholly a furnace question whether a dryer should be installed; it is not at all a pulverizing or storage question. Labor is reduced to a minimum. Slack coal at low cost yields its last B.T.U.

Jan 11, 1915

By John W. Cahn, John E. Hilliard

Single crystals of copper and silicon-iron were cold rolled in orientations chosen to produce individually the major components of the poly crystalline deformation texture. The orientation dependence of the recrystallization kinetics was studied relative to the primary recrystallization textures of these specimens. It is not possible to rationalize the poly crystalline re crystallized textures on this basis. The results suggest an important role of the interaction of adjacent crystals during the deformation of aggregates. BRICK and Williamson1 first noted evidence that the recrystallization temperature was different for straight-rolled and cross-rolled copper given comparable reductions. Michalak and Hibbard2 investigated quantitatively the effect of rolling procedure on the kinetics of recrystallization of cold-rolled copper and found that material cold-rolled the same amount by straight-pass, cross-pass, and compression-pass techniques developed different deformation and recrystallization textures, different 1-hr recrystallization temperatures, and different recrystallization kinetics. However, the temperature dependence of the rate of recrystallization was essentially the same for all techniques. Similar results were obtained on iron. Dunn and Koh3 in studying the recrystallization textures of cold-rolled silicon-iron single crystals reported large differences in the annealing temperatures and times required to recrystallize specimens of different orientations cold-rolled the same amount. Liu4 and Liu and Hibbard5 utilized the concept of different recrystallization temperatures for different orientations of cold-rolled crystals to rationalize the difference in recrystallization textures found in various face-centered-cubic metals. Their explanation predicted a significant difference in the recrystallization kinetics of deformed (110) [112] crystals as compared to (358) [352] crystals, and, in fact, Liu4 reported evidence that this difference existed at least qualitatively. Verbraak6 who rolled and recrystallized a series of copper single crystals found that the double (112) [111] rolled orientation is related to recrystallized cube texture formation. The effect of rolling intensity on the relative amount of cube component suggests an important role of recrystallization kinetics. Walter and Hibbard7 while trying to relate the behavior of rolled and recrystallized single crystals of silicon-iron to the behavior of polycrystal-line silicon-iron again noted that differences in recrystallization kinetics were necessary to rationalize their results. The purpose of the present investigation was to obtain quantitative kinetic data on the recrystallization of single crystals of both copper and silicon-iron rolled to initial isolated individual orientations corresponding to those found in the polycrystalline deformation textures. These data might indicate the importance of the deformation orientation, i.e. the range of available nuclei, the deformed matrix orientation into which these nuclei grow, and the orientation dependence of their growth rate during primary recrystallization on this texture. I. COPPER Experimental Procedure—A single crystal of 99.98 pet purity copper, grown by the Bridgman technique, was purchased in the form of a bar 1 1/2

Jan 1, 1962

By Richard Rice

TURBO blowers for blast-furnace blowing have now been in use for some years, and a review of the experience gained and the present state of progress may be interesting. FIG. 1.-STEAM TURBINE DIRECT CONNECTED TO AIR COMPRESSOR. The first blast-furnace blowing engine of this type to be installed in America was built by the General Electric Co. and is installed at the oxford Furnace of the Empire Iron & Steel Co. This machine was put into operation March 8, 191.0. A duplicate unit is situated at the furnace of the Northern Iron Co. at Port Henry, N. Y., which unit was put into opera ion June 30, 1910 (Fig. 1).

Jan 5, 1914

[59H1-Water Law and Its Significance to the Mining Industry by Wells A Hutchins 59H2-Relation of Land Subsidence to Groundwater Withdrawals in the Upper Gulf Coast Region, Texas by Leonard A Wood and A G Winslow 59F3-Hydraulic Mining of Gilsonite and Its Application to Coal Mining by J H Baker 59H4-Recovery of Phosphates by In Situ Fluid Mining by Sylvain J Pirson 59F5-Coal Cleaning Plant Design for Minimum Operating Labor by Wm M Bertholf and John D Price 59F6-Coke Combustibility A Neglected Characteristic by J D Price 59B7-Union Carbide's Uranium Operation at Maybell, Colorado by K W Lentz and F T Temple 59H8-A Rapid Method for Estimating Alumina in Feldspathic Sands by Hugh H Bein 59H9-Water Laws as Related to Dredging in Idaho by Robert A Lothrop, Richard B Porter, and Robert P Porter 58B19-Separation and Washing of Alumina Process Residue by Morton Handelman 59B11-Feed Preparation and Froth Modification for Fatty Acid Flotation by Carl C Martin and Burt C Mariacher 59B12-Design Requirements for Tailing Disposal in the Southwest by E Vern Given 59B13-Semi-Dome Shaped Buildings for Bulk Storage by Edward E Ives and William L Payne]

Jan 1, 1961