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Jan 1, 1938

By E. T. Knight, John D. Gill

Much has been written and said concerning the alleged wasteful and uneconomic use of natural gas and petroleum. Espccially condemned has been the use of natural gas for the production of carbon black and the use of heavy fuel oil under steam boilers.' The critics of these usages of gas and oil have sought to make effective their verbal attacks on the industry by the repetitive expression of the words "inferior" and "superior" uses2 of petroleum. Thus, to employ natural gas for residential heating was to use it in a superior way; to use it for the production of carbon black was to use it in a wasteful and uneconomic way. To use petroleum for the production of automotive fuel was to use it in a superior way; to employ it as a residential fuel and as the prime source of power in an industrial plant was to use it in an inferior and uneconomic way. No doubt the objections to such employment of gaseous and liquid natural hydrocarbons originated in the belief that natural gas and petroleum are limited, nonregenerative mineral resources, and that the functions they perform can be just as well performed by other natural resources like coal13 of which practically unlimited reserves are known. The generations that have dominated each of the last four decades have counted reserves4 of petroleum in terms of a few years supply. Meanwhile, domestic demand for motor fuel rose spectacularly from a few million barrels in 1900 to more than 500,000,000 bbl. last year.5 The more imaginative and vocal critics drew startling word pictures of the catastrophe of 25,000,000 motor vehicles made useless and of the great automotive manufacturing and allied industries brought to an untimely end, and millions of workers left hopelessly unemployed by what they called the deplorably rapid depletion of the petroleum reserve. Many of the critics have been sincere advocates of the conservation of natural resources; many others, and in recent years probably the majority, have espoused the doctrine of conservation to promote their own self-interest rather than that of the public. The latest advocate of severe restriction in the use of petroleum for the alleged purpose of conserving the petroleum resource proposes to achieve that end by a bill,6 now before

Jan 1, 1938

By Will Coghill

FLOTATION has been so closely allied with the sulfide minerals and their early and associated oily reagents that the term "oil flotation" has erroneously been applied to the entire flotation process. Today, the term "chemical flotation" might be used to advantage. Flotation literature has dealt primarily with the removal of sulfides from non-sulfide gangues, and the separation of one sulfide from another. Now, the application of the process to the separation of nonsulfide minerals is coming to the fore; and from the standpoint of the number of commercial minerals involved, the flotation of nonsulfides offers the larger field. Here, soap or soap-forming substances, such as the fatty acids and their derivatives, are used; hence there may well be a subdivision of the chemical flotation process called "soap flotation." Early experimenters learned that it was easy to form a froth or foam that would carry a part or all of the ore charge over the lip of the flotation machine; but this could not be regarded as flotation because of the lack of selectivity. Doubtless soap was one of the first reagents tried, and doubtless it was rejected on account of its gangue-carrying properties. Now this same gangue-carrying ability makes soap an acceptable reagent, for we are dealing with that, which among sulfides, is considered "gan-gue." As in the flotation of sulfides, so in the flotation of nonsulfides, the selective flocculation of the mineral and the dispersion of the gangue are the first objectives. In fact, these two phenomena epitomize flotation. They depend upon the unlike surface properties of the respective miner-als; and as long as the components of an ore have unlike surface proper-ties, a separation is possible, at least in theory. Often in nonsulfide flotation it makes little difference which mineral floats and which is depressed; generally only a separation is sought.

Jan 1, 1932

By E. H. Kelton

The purposes of this paper are to describe the use of adjustable cut and draw tools as a control test of drawing properties and to point out that no other well-known test or combination of tests determines this quality in zinc and zinc alloys. Rolled zinc has been used for making drawn articles, particularly battery cans, for many years. The development of rolling treatments satisfactory for these purposes followed the usual course of trial and error experimentation depending upon cooperation with customers to determine what type of material was suitable. A quick test of drawing quality was highly desirable, of course. Scleroscope hardness and temperll having no apparent relation to drawing quality, were used simply to check the duplication of rolling treatment and grade of metal. The dynamic ductility1 test, on the other hand, was believed to be so like the drawing operation as to provide a reliable index and came to be taken as the criterion of good drawing properties. Faith in this test was strengthened by the fact that metal having the highest ductility was more satisfactory for operations, such as the manufacture of battery cups, that required several redraws. No distinction was made at that time in specifying metal as to whether it was to be subjected to simple cut and draw, redrawing or forming operations. It developed, however, that in some grades of metal the highest ductility did not coincide with the most satisfactory quality when the material was used for a single draw. When zinc-base alloys, with their wider ranges of effective rolling treatments, came into increased use, their dynamic ductility and drawing quality appeared to have no connection whatever. Furthermore, comparisons of known drawing quality with other physical properties of the metal, including tensile strength, elongation and dynamic cold bends, were fruitless in yielding any clear relationship. Almost any test value produced in one piece of metal could be duplicated by another rolling or annealing treatment with attendant different drawing characteristics.

Jan 1, 1934

By Robert L. Zook, Bernard J. Olup, James J. Pierre

Coal refuse slurry impoundments are dams constructed of coarse coal refuse to impound fine refuse (slurry) and water (25 to 30% solids). Both products are waste from coal preparation plants. A number of these structures in West Virginia, Pennsylvania, and Kentucky were investigated to determine embankment stability. During the investigation a variety of embankment designs were encountered. The investigation determined the soil and geological characteristics of the embankments and the sites. This was accomplished by a test drilling and monitor installation (observation wells and piezometers) program, geologic study, and large-scale mapping which allowed subsurface profiles of the embankments to be constructed. The laboratory testing program concentrated on textural classification of the coal refuse, permeability, and determining strength parameters to be utilized in the stability analyses. For the stability analyses, the modified Fellenius slip circle, simplified Bishop slip circle, and analysis for translational failure were utilized. In all stability analyses hydrostatic pressure and seismic acceleration probability were considered. This investigation indicated that 62% of the embankments analyzed were in a stable condition. The coal seam, the type of roof rock, and the gradation of the refuse influence the degree of compaction obtainable and the permeability of refuse. The shear strength of coal refuse appears to be controlled by its composition, moisture content, degree of compaction, amount and grain size of fines present. This investigation demonstrated these embankments should not be treated as pure state-of-the-art dams consideration must be given to the particular properties of coal refuse and the total refuse disposal system. Refuse dam slurry impoundments generally lack the site selection phase that is standard practice with siting most other types of dams.

Jan 1, 1976

By W. H. Durrell

DISCOVERY of large iron ore deposits in New Quebec and Labrador is, undoubtedly, one of the outstanding mining events of the twentieth century. To give an idea of size, the present concession is almost equivalent to a strip a mile wide around the earth at the equator. Importance of this iron ore area can best be appreciated by comparison to the famous Mesabi Range. On Mesabi, the area of favorable rock is 110 miles long and from 1 to 5 miles wide, with a, productive zone about 70 miles long. On the con- cessions the area of favorable rock in the Labrador Trough is 225 miles long and from 10 to 60 miles wide. In Quebec-Labrador, exploration already discloses that the productive zone is 90 miles long, with good chances of being extended at both ends. The Mesabi is covered generally by thick over- burden, and the iron ore deposits were found by T- test-pitting and systematic test-drilling. In Labrador and Quebec, most ore has been developed from a few surface deposits, and when it is considered that at least 95 pct of the area is covered by over- burden, and that there remains thousands of square miles of favorable territory still to be explored, it can be seen that the possibilities for developing additional ore are tremendous.

Jan 4, 1954

By J. Koskinen, P. Vanninen, T. Leskinen, A. Leppala

Continuous and accurate analysis of slurries has become a critical requirement in mineral processing. With on-stream assay data, automation procedures can be employed to obtain higher recovery and improved control of production. The Courier system was developed by Outokumpu Oy, taking advantage of mineral processing know-how, to provide means for achieving these objectives in the company's ore concentrator operations. It became evident, based on early experience with on-stream analysis, that the Courier should be a complete system to fulfill all functions of the analysis operation. The system includes equipment and techniques for primary sampling, sample preparation for assaying, and processing of data for final assay results. In addition, the on-line X-ray spectrometer unit was developed specifically for industrial use, incorporating a number of technical advances. A new system for converting spectrometric data to assays is based on a physical model programmed on a digital computer. The Courier system is furnished on a turn-key installation basis incorporating all elements needed for operation including calibration. The experience to date with the Courier system at the Pyhäsalmi concentrator is summarized. Reference is also made to recent results with installations at the Outokumpu and Vihanti concentrators.

Jan 1, 1972

By D. G. Peterson, W. J. Guay

The extraction of gold from refractory ores containing activated carbon and various types of carbon compounds is being done commercially for the first time at Carlin, Nev., by Carlin Gold Mining Co. Oxidation of the carbonaceous materials to CO and CO,- is accomplished by the introduction of chlorine into an aqueous pulp. The chlorine reacts with the limestone in the ore to form calcium hypochlorite which in turn reacts with the carbonaceous matter to form calcium chloride, CO, and CO.. Following the oxidation treatment the ore is cyanided in the conventional manner. For the first six months of operation the plant averaged 83% extraction at a feed rate of 500 tpd and a consumption of 28.4 lb chlorine per ton of ore which showed only 33.5% extraction by conventional cyanidation without the oxidation pretreatment.

Jan 1, 1974

By LE B. GRAY

ALL meeting of the Chemical Section, National Safety Council, in Rochester, N. Y., put his hand on at least ten salient points that apply to safety in nearly any laboratory ; these are as follows : 1. Impress your laboratory worker at the start that he is dealing with powerful and dangerous-forces and that every experimental set-up must be studied from the stand- point of its fiber, electrical, explosive, and health hazards.

Jan 1, 1929

By I. L. Barker

ALTHOUGH valuable information has been pub-lished on the important problems of slag losses with which every copper metallurgist has to contend, a great deal of money is still being wasted in copper smelters all over the world, through metal being irretrievably lost in reverberatory slags. When smelting a relatively low-grade pyritic concentrate together with a proportion of direct-smelting oxi- dized ore, as is done in Oroya, slag volumes are of necessity high, and even a relatively clean slag, say of 0.5 pct Cu, means a loss of almost 4 pct of all the copper charged, or over $1,000,000 annually at present output and prices. While it is known that such losses can often be reduced by allowing the slag time to settle, with or without addition of a reducing agent such as coal or pyrite, the facilities for such treatment are not always available in a plant of old design working to capacity under severe space limitations. Nor is it easy under such conditions to run large scale tests which may endanger the smooth flow of production for considerable periods without yielding

Jan 1, 1958

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

Jan 8, 1917

By G. G. Griswold, B. S. Morrow

The copper-bearing ores concentrated at the Anaconda plant of the Anaconda Copper Mining Go. are principally a mixture of copper and iron sulfides associated in a gangue consisting of quartz, lightly altered granite and feldspars, with sphalerite and galena and more rarely barite and hubnerite as accessory minerals. The predominant sulfide is pyrite. The copper minerals present are: chalcocite, bornite (erubescite), enargite, chalcopyrite, covellite, tetrahedrite and some tennantite. Normal concentrator practice removes a slime prior to ball-mill grinding. The deslimed ore is ground to approximately 10 per cent plus 65 mesh for flotation. Two selective flotation circuits are used, one for deslimed ore and one for slime. Microscopic studies of concentrator products disclose such an interlocking of copper minerals with pyrite that any material increase in concentrate grade entails additional grinding unless recovery is sacrificed to a considerable extent. During the latter part of 1931 and the early part of 1932 the problem of producing a high-grade concentrate (40 per cent Cu) with at least no

Jan 1, 1935

By Everett Parker

THIS paper describes the methods used to determine the rates of payment for contract work and the plan of contract supervision in the Elm Orlu mine. A discussion of the theory of wages and the eternal question-what is a just wage-are beyond the scope of this article. In the fall of 1920 the Elm Orlu was the largest mine in Butte using the day's pay system of payment for stoping operations. High labor and supply costs and a falling market for the product of the mine made economic mining difficult. The mining method had been changed from the square set stoping to timbered rilling to eliminate most of the shoveling. There was no opportunity to reduce the cost of supplies other than more rigid economy in their use. It was recognized, however, that the labor efficiency was low and that the reduction in costs depended on increasing the output per man. While in general, the low man efficiency was a resultant of the high wages paid and the shortage of men during the war and subsequent period of inflation, it was felt that the contract and bonus system used in the other mines was the main factor in that the most capable and energetic men had been attracted to those mines where more than average skill and dili-gence were recognized by more than average pay.

Jan 1, 1927

Man: A purely detached consideration of nature and the place of man in it may easily result in somewhat pessimistic conclusions as to man and his destiny. However, when we come to the evaluation of man's role in the development of natural resources and his achievements in this field, a more optimistic tone may be justified. Hence the possible contradictions between Man and Nature, Perfection, and the present chapter are more apparent than real. After all, progress must have a foundation of optimism, and we cannot challenge either the faculty or the students to better work and to a progressive and constructive outlook without an underlying tone of optimism and basic faith in the future. Geology is the basic science of Mother Earth; the science of the natural forces that have produced and modified the structure of our globe; the science of minerals and rocks; of landscapes and soils; of water supply and mineral resources, including mineral fuels; and of the history of life, both plant and animal, as revealed by fossils in rocks. It is difficult to reduce man and his historical significance to their proper relationship with regard to the earth and its history. Processes of rock formation have continued for at least two billion years; man's activities have been in evidence only a few thousand years. As a means of comparison, if the height of the Empire State building were to represent geologic time, the thickness of a nickel placed on the tower would just about repre-

Jan 1, 1950

By Richard Moldenke

So far as the quality of the product is concerned, the history of the production of pig iron for foundry purposes is one of constant retrogression. The steps in this deterioration began with cold-blast charcoal pig iron, then anthracite iron, coke iron; then gradually warm to hot-blast coke iron, with the charcoal furnaces also heating their blast to get greater tonnages, and finally the present-day hot-blast coke irons with scrap additions to the ordinary burden that, according to one European report, have gone as high as 65 per cent. Parallel with this quality retrogression is the enormous increase in furnace tonnages from about 15 to over 1000 tons per day in excep tional instances of modern practice. The key to this situation is economic pressure. The effect is a growing differentiation between furnace production for gray iron and malleable foundries and for the production of commercial steel. As the foundry is often compelled to draw upon the pig irons made for steel purposes, for economic reasons, whereas the steel industry does not draw upon foundry pig irons proper, the situation is resolving itself into one of grave consequence for the life of the gray-iron castings industry, and hence the intensive present-day feeling in foundry circles for rigid specifications to govern the quality of pig irons sold for foundry use. In the discussion of a paper on the use of scrap in the blast furnace held recently in the Institute, a very pertinent remark was made by one of the participating furnacemen, who confessed that "the things found wrong by the foundryman with his iron were beyond his depth." It may be added that those things are also beyond the depth of most foundrymen who, however, know from their results that they are getting poorer castings today with many pig irons than they did with those same brands in former years. Under the former fracture buying, the foundryman at least could select the strongest metal, as judged by the sledge, from various brands of similar fracture and pig section, and his results proved

Jan 1, 1927

By J. W. Harden

APART from the merits of the respective systems of mining under conditions alike, there is much in the nature of the coal and the measures with which it is associated, to make that system which is successfully practiced in one locality ill adapted to that of another ; the structure of the coal itself, the roof, the floor, the depth and character of the overlying strata, each exercising more or less controlling influence. Again, in the highly bituminous districts, and with such as have caking coals, where the size of the coal as it comes off the face does not affect its value, as the very smallest of it may be utilized, and in the hard, the open and free-burning coals, in some of which the round only (large coal) is merchantable,

By Harrison Schmitt

The Parral area, a part of the Parral mining district of Southern Chihuahua, is situated in and near the City of Parral, with the most important mine of the district, La Prieta, lying within the city limits. The famous Veta Colorado and Palmilla veins near Villa Escobedo or Minas Nuevas are a few kilometers to the northeast (see Fig. 1). The chief metals produced are silver, lead and zinc, with some copper and gold. This area was one of the earliest to produce metal in Mexico, according to records at Parral, which show that mining started in 1632. In near-by Santa Barbara, however, mining had begun 85 years earlier. It is said that when silver was discovered in the Veta Colorado, the Santa Barbara gold deposits, at that time nearly exhausted, were immediately abandoned for the more profitable silver mines at Minas Nuevas (New Mines) During the post-revolutionary period, 1923-1928, the author made many trips to the Parral district to do mine examination work for several units of the American Smelting and Refining Co. This paper is an abstract of some of the geologic data collected, together with the results of a microscopic study of the ores and rocks—the latter investigation made at the University of Minnesota—and is intended to supplement one recently published. Topography The Parral district lies in the eastern foothills belt of the Sierra Madre Oeste. The area is about evenly divided between fairly flat to rolling plains and mesas on the south and rounded hills to rough precipitous slopes on the west and north. The relief is approximately 550 m. (1800 ft.). The areas of intrusive monzonite and Jurassic (?) sedimentary rocks give rise to a topography of low rounded hills and relatively flat valleys; as contrasted with the volcanics, with their alternating beds of soft

Jan 1, 1931

By Benjamin Miller

FROM earliest recorded times, limestone has been employed in the industrial life of peoples of all sections of the world where it exists. It is widely distributed and therefore has been available in almost every country and has been employed for a variety of purposes. Its earliest use was for buildings, since it is more easily quarried and dressed than most other kinds of rocks and so could be utilized by early inhabitants, poorly equipped with tools. The next use was in the manufacture of lime, which was employed by the ancients in mortar. These two uses of limestone are still all important, but they have been overshadowed in scores of regions by literally hundreds of new applications for raw lime-stone or products made from it. Anyone familiar with modern manufacturing processes can quickly call to mind many industries in which limestones are essential, and new uses are continually coming to notice. Any enumeration would probably be incomplete and soon out of date.

Jan 1, 1935

By J. P. Sheehan, W. R. Hibbard, M. Baeyertz

This paper deals with molybdenum modifications of 5140 steel that have the same hardenability but a better tolerance for phosphorus than the AISI-SAE 5140 grade. Lack of toughness in steels with higher than normal phosphorus contents is well known to metallurgists. This problem is troublesome even within normal phosphorus ranges, if the heat treatment or the design of the part or the service is critical. Under such unfavorable conditions and also in the case of phosphorus contents toward the upper side of the commercial range, the use of molybdenum to replace a part of the chromium in 5140 steel provides a factor of safety. The toughness of steel is variously exhibited in different mechanical tests; broadly the term is applied to the capacity of the steel to deform prior to fracture. Defined in this way, toughness is considered to be an inherent quality that depends upon the composition and structure of the steel, and also upon its temperature during deformation and fracture in the test. In the present state of our knowledge, the type of mechanical test needs to be included in any discussion of toughness, because the revelation of this quality in steel depends on the stress state and rate of stressing imposed by the test. In comparing the toughness of one steel with another by laboratory testing, it has long been customary to use notched tests that impose severe constmint to deformation, and then to test over a range of temperatures to obtain the so-called transition. At temperatures above the transition, the steel fails after considerable deformation and absorption of energy. Below the transition, less energy is absorbed as the steel fails largely by cleavage. The transition range itself is characterized by a more or less abrupt change in energy absorption and type of fracture. The conventional V-notch Charpy impact test has been used exclusively in the work covered by this report. For the steels under study, rather sharp transitions are obtained with this test, at testing temperatures that are easily obtained in the laboratory. The position of the transition on the testing temperature scale provides a rather sensitive index of the toughness of the steel, when the steels under study are similar in character as they are in this work. Turning to the metallurgical reasons for the greater toughness of one steel as compared to another, the authors propose to limit the discussion to the small field under study. Only one structural state is considered, tempered martensite of a hardness of about 28 Rockwell C or 269 Brinell. The study deals first with the loss of toughness in AISI-SAE 5140 steel caused by increasing the phosphorus content from about 0.020 to 0.040 pct. A second part of the work deals with counteracting this loss in toughness by replacing a part of the chromium by molybdenum. A series of molybdenum modifications was studied, in each of which the chromium was reduced sufficiently to duplicate the hardenability of 5140 steel. Phosphorus affects the toughness of steel in two ways. An inherent lack of toughness of phosphorus-bearing ferrite as compared to low phosphorus ferrite has often been noted. Jolivet and Vidall have shown that phosphorus has the same effect in tempered martensite in chromium steels. The other well known effect of phosphorus is to make steel susceptible to temper embrittlement. Temper brittleness is a loss in toughness brought about by tempering steel within a limited temperature interval somewhat below the A1 temperature. In most of the standard AISI-SAE alloy steels, this temperature interval is approximately 850-1100°F. Either of these types of loss in toughness is easily followed by the shift in the transition temperature obtained with the notched-bar impact test. The data to be presented show the beneficial effect of substituting molybdenum for a part of the chromium in 5140 steel with either moderate (0.020 pct) or high (0.040 pct) phosphorus contents. Both the inherent lack of toughness of phosphorus-bearing steel and temper brittleness are counteracted by this use of molybdenum. The work of Jolivet and Vidal mentioned above shows the detrimental effect of phosphorus on the toughness of tempered martensite in the absence of temper embrittlement, as well as the temper brittleness caused by phosphorus. They used two steels, essentially 0.25 pct C-1.4 pct Cr, with 0.044 and 0.013 pct P, respectively. The nonembrittled state was obtained by quenching in oil from 1610°F, then tempering for one hour at 1200°F and quenching in water. In this state the transition temperature range of the low phosphorus steel in the notched-bar impact test was below that of the steel with 0.044 pct P. An additional treatment of 24 hr at 975°F (that is, in the embrittling range) caused both steels to lose toughness, but the high phosphorus steel showed the greater embrittlement. Recently Hollomon2 has published a comprehensive survey and bibliography of the literature on temper brittleness, to which the reader is re-

Jan 1, 1950

By N. J. Grant, E. Gregory

The creep rupture properties of wrought aluminum powder products made from five grades of sintered aluminum powder were investigated at temperatures from 400° to 900°F for rupture times up to 1000 hr. The effect of stress concentrations on materials of this type was investigated by means of notched creep rupture tests. A tentative correlation was obtained between the creep rupture properties and the structure as revealed by electron micrographs. SEVERAL papers have been published recently concerning the production and properties of wrought aluminum powder products and their possible high temperature applications. Most of the published work in this field has come from abroad, notably Switzerland, and articles by Irmann and his colleagues were summarized in English recently.'.' Most of the papers published by Dr. Irmann are principally concerned with the retention of properties (by a product which is produced from extremely fine flake powder and is subsequently hot extruded) after heating to high temperature for prolonged times. The powder may be in atomized or flake form, and during hot working the applied pressure is reported to plastically deform the aluminum powder, thus breaking the oxide skin and welding the particles together. Irmann attributes the remarkable properties to the dispersion of oxide inclusions. Specifically, the product described by Irmann is one labeled SAP (Sintered Aluminum Powder) in which the initial flake powder is so fine that at least 50 pct of the flakes have one dimension of 2 microns or less. The composition of the starting aluminum shows in percent, Fe, 0.18; Si, 0.19; Zn, 0.06; Ti, 0.03; Cu, Mn, Mg, all nil; balance Al, approximately 99.5 pct. Aluminum is not the only material that has been found to have increased resistance to deformation at elevated temperatures when produced by powder metallurgy. It has been reported by Middleton, Pf eil, and Rhodes- hat platinum has a higher recrys-tallization temperature when produced by powder metallurgy and exhibits peculiar properties, many of which are similar to those of the aluminum powder products. Difficulties were encountered in explaining the reason for the strengthening in the case of platinum since the existence of the oxide is doubtful. The authors attributed the special properties to "a small amount of suitably dispersed porosity." This theory was supported by von -~eer-leder4 in the discussion to the paper, and the similarity between this method of hardening and that suggested by Rohner in his theory of age hardening was pointed out. R. de Fleury5 attempted to explain some of the properties in terms of the modulus of elasticity and elastic limit of alumina and aluminum while von Zeerleder examined the relationship between the yield strength and the reciprocal of the powder particle size. Boenisch and WiderholtQ dealt mainly with the corrosion resistance of the powder aluminum material and compared it with other aluminum alloys. The diffusion rates of other metals in SAP and pure aluminum have been compared by Seith and Lop-mann.' They showed that the alloying metals diffuse particularly quickly in SAP possibly due to the very fine grain size. The properties of the Alcoa products were given by Lyle.' The creep rupture properties of SAP and two of the Alcoa experimental powder products were compared by Gregory and Grant hnd it was shown that these products are vastly stronger at 900°F than are the best cast and wrought alloys at 600°F. Since the publication of these data, the authors have investigated two further aluminum powder products and it is the object of this paper to show how the high temperature creep rupture properties of the five materials vary with oxide content and with the structure as revealed by electron microscopy. Materials One of the five products, SAP, a sintered aluminum product, was supplied by the Societe Anonyme pourl Industrie de l,Aluminium, Neuhausen a/RHF, Switzerland, through Dr. R. Irmann, while the others, M276, M257, M293, and M255 were supplied by the Aluminum Company of America as experimental powder metallurgical products. M255- and M293 were made from coarse and fine atomized powders, respectively. The other materials were made from flake powders with significant differences in oxide content, the details of the type of powders used in the manufacture of these materials

Jan 1, 1955