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By E. H. Jr. Dix

DURING an investigation of high-strength manganese bronze by the Engineering Division of the Air Service, at McCook Field, Dayton, Ohio, particles of a "blue constituent" were noted in the microstructure of most of the bronzes examined. The constitution of the simple copper-zinc base alloy is still a matter of dispute in spite of the fact that the copper-zinc series is one of the oldest industrially important groups of alloys, and has received the early consideration of scientific research. The diagram, according to the most recent work,1 is shown in Fig. 1. The disputed questions involve the termination of the beta field and the line at 470° C. The earliest experimenter, Roberts-Austin, detected an arrest in some of his cooling curves at approximately this temperature and ascribed them to the formation of a eutectic; it has since been proved that there are no eutectics in this series. Shepherd2 was unable to detect any thermal arrests at this temperature; his diagram was essentially as shown in Fig. 1, except that the line at 470° C. was omitted and the beta phase carried down to normal temperatures. Later, Carpenter and Edwards,3 by a very painstaking research, definitely established the authenticity of the line but attributed it to the breakdown of the beta constituent into a eutectoid of alpha and gamma. Microscopic evidence of the formation of the eutectoid is doubtful and it seems more likely to be due to an allotropic change in the beta constituent as shown by Fig. 1. At least for practical purposes, it is more convenient to think of the structure of a 60-40 brass as a mixture of alpha and beta prime crystals rather than alpha plus an unresolvable eutectoid of "apparent beta" as it has often been called.

Jan 5, 1922

By T. A. Wilson, S. L. Hoyt

The plastic deformation of slender single crystals of zinc has been described in some detail in the paper by Mark, Polanyi and Schmid,' which has become a classic, and also by one of the present authors in a somewhat shorter account. 2 The study of single-crystal zinc is termed classical because zinc single crystals offer, perhaps, the best material yet available for the study of atomic behavior during deformation and the effect known as "strengthening" in metals. A considerable amount of additional work has also been done on single-crystal zinc, but as it is not closely related to the present paper it will not be considered. Throughout all the former work, the mechanism of plastic deformation first described by Mark, Polanyi and Schmid has been assumed to hold. This may be said to offer the strongest confirmation of its correctness. Even so, the picture of the process has never been as completely portrayed as is desirable. The first object of the present paper is to describe work that has been done in this field, and which is even yet being carried on, in the hope that a more complete picture may be obtained. Mathewson and Phillips3 have recently described a new mechanism of the deformation of zinc based on their study of large rectangular crystals. One of their conclusions was that deformation produced twinning with a rotation of some of the basal planes into positions 94" removed from their original position; a position almost the same as that of the prismatic planes before twinning. A second conclusion was that fracture occurred along these basal planes in their new position, and, therefore that fractures previously regarded as prismatic were in reality basal. Such findings are of great significance and they raise a question as to the generality of such behavior. Professor Mathewson's opinion is that even the slender cylindrical single crystals behave in the same manner as his large rectangular crystals when strained by simple tension.

By T. G. Fulmor, William Wraith

What impelled The Anaconda Company to dismantle and move a concentrator 25 miles that was already operating at a rate of 35,000 ton per day? The answer to that question takes in almost exactly 49 years and perhaps 10 complete cycles of the metallurgical wheel in the Anaconda, Mont., mill. One could say with truth that the move is a logical next-step in the development of metallurgy in The Anaconda Co. In the old concentrator at Anaconda, the background story is unfolded: - Gravity separation by jigs, later supplemented with gravity tables, 1905. - Separate sand and slime froth flotation, 1915. - Acid bulk froth flotation, 1917. - Bulk alkaline flotation, 1926. - Alkaline flotation of total ore without sand- slime separation due to change in ore type. 1939.

Jan 5, 1964

THE slag performs two useful functions in open-hearth steel- making. First, it is the means of disposal of all the impurities, save carbon, which are removed from the charge materials in refining the steel, so it must be suited to receiving and retaining as much as possible of undesirable elements with minimum loss of iron and useful alloying elements. Second, the slag serves as a buffer between the flame and the bath and transfers oxygen to the metal at a measured pace contrasted with the violent and difficultly controlled oxidation of the bessemer process. At the same time, the slag is a thermal insulator that limits the rate at which heat can be delivered to the metal from the flame, and a heavy slag blanket thereby serves as a brake on production rates. It has been said with justification that the secret of good steel- making is to make a good slag and the steel will take care of itself. In a broad sense, the subject of slag control includes not only the adjustment of the composition of the slag but also of its relative weight in terms of percentage of the metal-bath weight. The slag is made up essentially of: (1) oxides formed by oxidation of silicon, manganese, phosphorus, and iron in the charge, (2) Si02, MnO, MgO, and other oxides charged as such or introduced incidentally with ores or fluxes or by refractory erosion, and (3) lime charged or fed to the heat to neutralize the "acidic" oxides present (Si02 and P205). Obviously, if practically perfect control were possible over the composition of the charge as well as over the oxidation process during the melting period, both slag weight and composition would be very nearly predetermined; and the control problem would be solved. Unfortunately, only a somewhat imperfect control over these factors is possible, so the operator must begin during the lime boil and continue through the refining period to discover and correct departures from the normal pattern of slag development. To do this as the heat progresses, the first helper must be able to make quick estimates of the composition and physical state of develop-

Jan 1, 1964

By H. S. Rawdon

One of the most vital problems in the manufacture of steel at present is the occurrence of the defects that have been popularly termed "snow flakes," "flakes," or "scabs." Particularly is this the problem of many manufacturers who, during the past 2 yr., have undertaken large-scale production for the first time. A study of the microstructure of such defective material throws considerable light upon the nature of these defects and is essential before measurcs may be taken for the elimination of the defects. Flakes do not appear to be found in the plain carbon steels; they have been found. however, in abundance in some of the simple alloy steels that are being used in such vast quantities; vie., nickel steel of the approximate composition, 0.40 carbon and 3.5 per cent. nickel, and in the chrome-nickel type. The present article summarizes the characteristic features of defective steel of the flaky type as they have been found by laboratory study of numerous specimens, and it aims to show the conditions within the metal that are favorable to the occurrence of this type of defect without entering into the details of mill practice (size of ingot, design of molds, rate of cooling, distribution of cooling stresses, etc.), all of which conditions appear to play a role in the production of these defects. MacrostrUctURe To one familar with flaky steel, the appearance of "snow-flakes" is unmistakable and is not to be confused with other types of defects. Figs. 1 to 6 show the appearance of fractures of steel showing this type of defect; the white silvery area, which always has the appearance of being of a very coarsely crystalline structure, in the specimen stands out in bold contrast to the darker background and readily justifies the use of the term "snow-flakes." Fig. 1 shows the appearance of the faces of the two halves of a nickel-steel forging that has been split to show the interior flakes. Fig. 2 is a nickel-steel bar (carbon 0.40 per cent.,

Jan 1, 1920

By A. C. Boyle

PaGE I. Introduction.........68 II. Location of the District,....... • 70 .. III. Stratigraphy...........73 Description of the Rocks.......73 Triassic Eruptives (Andesite Flows and Tuffs) ....73 Triassic Sediments (Shales and Slates)..75 Areal Geology ............75 Structure...-.......76 Folds............. 76 Faults..........79 Shear ...........80 Intrusives..........81 Alaskite Dike.........81 Andesitic Intrusion.......82 IV. PetrogRaphy of thE Rock Types......83 Andesite Flows.........84 Tuff 8...........84 Andesite Tuff........84 Rhyolite Tuff.....-.......85 Alaskite-Porphyry.......89 Andesite Dike........91 V. Description of the Mines......92 VI. Metalliferous Deposits ........ 95 Character of the Ores...........97 Mineralogy of the Ores.......97 Metallic Minerals.......97 Microscopic Character of the Ores...98 Secondary Enrichment....... 103 Genesis of the Ores ...........104 VII. The Sulphate Deposits.......109 Gypsum ..... HO Anhydrite......... ,... 110 Barite............ 110 Origin. with special reference to Gypsum....111 VIII. Summary.............. 113 IX. BIblYogRaphY.............114

Jan 1, 1915

By N. A. Ziegler

IN every research it is desirable to eliminate as many variables as possible and to leave only a few to be investigated one at a time. Metallurgical problems are no exception. Some of the variables that are difficult to control are the size, the distribution, and the orientation of the grains in a metallic test piece. It is therefore very desirable to obtain isolated metallic grains (single crystals, as they are commonly called) large enough to enable one to study their mechanical and physical properties. The present investigation is a part of magnetic research work on iron and iron alloys, undertaken to obtain, if possible, the magnetic properties of pure iron (Fe). This paper will deal primarily with the preparation of single crystals of iron and their mechanical properties, while another paper, by T. D. Yensen, now in preparation, will deal specifically with their magnetic properties. The work with "single crystals" is attracting more attention every year among the investigators in metallurgy. Van Liempt1 gives an interesting summary of the work done and the different methods used in the preparation of metallic single crystals. Briefly stated, the four principal methods used are the following: 1. The cooling of a liquid metal in such a way that the crystallization would start at one point only, causing the entire liquid to solidify as one crystalline unit. This method can be successfully applied to the majority of the metals that do not have any allotropic transformations in the solid state. It has been used and described by a number of investigators,2 but it has never been successfully applied to iron on account of allotropic transformations.

Jan 1, 1930

By W. R. Crane

The support of roof in mines is dependent largely on the character of the top rock and its occurrence. The formations overlying the orebed in the Birmingham district are sandstone and slate. The sandstone occurs in beds of sufficient thickness to constitute important elements in the system of support; the slate is relatively strong but is thinly stratified. The alternating beds of sandstone and slate furnish an excellent combination in that the former are strong and the latter are impervious; however, their continuity is broken by jointing or slip planes. The thickness, and consequent weight of the overlying formations, is important in so far as the size and arrangement of pillars are concerned but may be relatively unimportant, temporarily at least, as a factor in the support of the roof. The position of the respective beds of sandstone and slate, their relative thickness, and their inherent weakness because of the occurrence of faults and folds, may exert a predominating influence on their support in place, which is affected only in part by the weight of the cover. The only mine in this district that operates under a cover of approximately 2000 ft. (1900 ft.) is the Shannon so-called "twin slope," situated 14,000 ft. southeast of the portal of the No. 7 mine of the Tennessee Coal, Iron, & Railroad Co. The conditions in this mine indicate what may be expected in other mines when the same depth is attained; in fact, the effect of pressure is shown in several mines that have not reached two-thirds of that depth. It is evident, then, that conditions affecting the support of roof will not improve but rather will become more difficult with the extension of the mines into the valley under a constantly increasing weight of cover. Further, the difficulties will probably be augmented by the occurrence of faults and other disturbed ground, the presence and position of which at present are largely unknown.

Jan 1, 1925

W. 0. HOTCHKISS,* Madison, Wis.-When we began to do geological field work in the Lake Superior region, we found a correlation in existence, and, as youngsters, accepted all that as settled. Both Mr. Allen and I, since that time, have seen a great many things that were not apparent nor visible to Van Hise, and those who worked with him; we realize now that the correlation was not final and that much remains to be determined concerning geology of the Lake Superior region. My attitude on this matter is that we should not publish an amended correlation as a final thing. We should avoid, in every way possible, foreclosing the minds of those who follow us in working in the geology of this region. As a matter of fact, no correlation can be final at present, because facts and data are accumulating so rapidly that every classification must be immediately modified to fit further observation. Consequently, my attitude in this matter would be, instead of saying that the iron formations of the Lake Superior region are all Middle Huronian, to say that there may be three Huronians-or four or five- we do not know. I believe it is better policy to hold to our present correlation. I do not believe there is any economic benefit to the mining man or the geologist working on problems relating to explorations for iron ore, that cannot be just as well solved by maintaining our present correlation, with a. wholesome idea of our lack of knowledge and the necessity for further detailed work. Then, if any new horizons are discovered in any particular range, the minds of the investigators will not be foreclosed because some one has said that all the iron formation is in the Middle so that there is no use looking elsewhere for it. There is use looking elsewhere, in many cases, as the ore deposits become exhausted.

Jan 1, 1920

By Persifor Frazer

The subject of Egypt, to use the words of perhaps the second of modern writers on the subject [Deodat. de Dolomieu, in Observations sur la Physique, etc., January, 1793, vol. xlii., pp. 41+, 108+; Abbe Rozier, J. A. Mongez, and J. C. Delametherie, Paris], is one which strongly excites our interest, and everything relating to it demands our respect. "Thus," he continues, "the Greeks appeared to the Romans," ..." thus Egypt appeared to the Greeks, and thus all three appear to us." This writer, in the three parts of the memoire given above, speaks of Norden as the modern pioneer of Egypt, and does not seem to have made original observations himself; nevertheless he seems to have rendered the same service to his authority that Playfair not very long afterward rendered Hutton. The limitations of a paper will permit little else than citations, but these are so numerous that, unless much compressed, they would supply a chapter of moderate size. A great deal of the very interesting memoire of Dolomieu is taken up with Quixotic tilts

Jan 1, 1883

By George Bain

METHODS of mining building stone of any sort are planned to pro-duce as few fractures as possible, and present a strong contrast to methods of mining metallic ores, which must be crushed eventually and have fractures produced in as great profusion as possible. Shocks transmitted to a stone invariably make it more porous and more permeable and reduce its effective life, therefore methods of mining building stone involve as FIG. 1. THE SUPREME COURT BUILDING, WASHINGTON, D. C. This building illustrates the fine detail of workmanship, unprotected sharp corners and thin edges, and tall narrow columns characteristic of marble structures. These features require exceedingly coherent stone, and preservation of these features for decades or centuries demands many special quarrying precautions to keep absorption to 0.14 per cent or less, a detail not essential to stone for coarser architectural types. few shocks as possible. This is singularly true for marble because marble structures are intended to have long life, greater delicacy of line, more gracefulness and fineness of sculpture than those made from any other structural material (Fig. 1). So that delicate lines may remain in almost perfect preservation for decades, or even centuries, it is important

Jan 1, 1935

By A Andersen

DURING an investigation of the copper-rich portion of the copper-silicon-iron system as part of an extensive research program on P.M.G. alloys, which was begun in 1937 in the research laboratory of the Phelps Dodge Corporation, it became apparent that the binary copper-silicon system below 7 per cent Si needed revision, therefore an investiga-tion was undertaken. Both X-ray methods and microscopic technique were employed. Despite the many investigations that have the clarification of this sys-tem as their object, no two successive reports on the system have agreed in placement of the alpha-phase solubility limit, and uncertainty about the secondary phase first to appear has been voiced several times.3,4,5 It was therefore not surprising, when T. Isawa's6 and M. Okamoto's7 works were reported at the time we were finishing up our experimental work, to find essential disagreement between their results and ours. But when C. S. Smith's latest work on the copper-silicon system8 was published just as we were finishing our laboratory report, it was indeed gratifying to find that the latter's diagram and ours checked in all essen-tial features, except the temperature of the peritectic line above 830° C. Many attempts were made to retain the beta phase during the present investigation, but none was successful. Isawa,6 however, reports that he has been able to obtain X-ray photograms of the beta phase. The structure, he states, is body-centered cubic with a lattice constant of 2.848 A.. at 7.2 per cent Si. Okamoto7 and Smith8 both use the designation Kappa for the hexag-onal phase, and to avoid confusion this designation will be adhered to in the present paper.

Jan 1, 1939

By F. W. Denton

Much has been written about the possibilities of the Vermilion and Mesabi ranges of northern Minnesota as producers of large quantities of high-grade iron-ore. The Mesabi range in particular has attracted considerable attention on account of the proximity of the ore-deposits to the surface, which has been as-

Jan 1, 1898

By Henry M. Howe

Jan 1, 1908

By Henry Rawdon

ONE of the most vital problems in the manufacture of steel at present is the occurrence of the defects that have been popularly termed "snow flakes," "flakes," or "scabs." Particularly is this the problem of many manufacturers who during the past 2 yr. have undertaken large-scale production for the first time. A study of the microstructure of such defective material throws considerable light upon the nature of these defects and is essential before measures may be taken for the elimination of the defects. Flakes do not appear to be found in the plain carbon steels; they have been found, however, in abundance in some of the simple alloy steels that are being used in such vast quantities; viz., nickel steel of the approximate composition, 0.40 carbon and 3.5 per cent. nickel, and in the chrome-nickel type. The present article summarizes the characteristic features of defective steel of the flaky type as they have been found by laboratory study of numerous specimens, and it aims to show the conditions within the metal that are favorable to the occurrence of this type of defect without entering into the details of mill practice (size of ingot, design of molds, rate of cooling, distribution of cooling stresses, etc.), all of which conditions appear to play a role in the production of these defects.

Jan 2, 1919

By Cyril Smith

SOMEWHAT over ten years ago the author described studies1,2 on the constitution of the copper-silicon system. The copper-rich portion of this diagram is shown in Fig. 1. The experimental points freely dotted about the diagram seemed to justify an otherwise unconvincing diagram and for several years the curious reverse bend in the alpha-phase bound-ary was accepted as substantially correct, even by later investigators3,4 of the system who introduced changes in the high-silicon phases. The binary diagram has been used as a base for several ternary systems" without any suggested changes. Voce10 suspected the existence of another phase from his study of the cast alloys in the copper-manganese¬silicon system, but evidently hesitated to extrapolate this to the binary diagram, particularly in view of the too ingenious explanation that was advanced" to account for the pools of constituent clearly visible in castings; namely, that they were secondary alpha of twinned orientation deposited from beta. Von Schwarz,12 in 1932, called attention to the fact that this micro-constituent in copper-silicon alloy castings was anisotropic under polar-ized light and asserted that a new phase, not cubic, should be placed in the diagram adjacent to alpha. Sautner,13 on the basis of investigations with the polarizing microscope and with X-rays, introduced this phase into the diagram at about 6 per cent Si. The relevant part of his dia-gram is shown in Fig. 2. Sautner called the new phase beta, renaming the old beta phase zeta. To avoid confusion, in redrawing Fig. 2 the phases have been renamed in accordance with the terminology adopted in the present paper, in which the new phase is called kappa and the other phases retain the designation given them by Arrhenius and Westgren.4

Jan 1, 1939

To Americans, Alaska occupies a unique position, both geographically and historically. The only integral portion of the United States lying in the sub-Arctic and Arctic regions of the Earth, the early remoteness and climatic conditions effectively combined to impede the economic development of this area. Although Alaska has been a part of our Nation since 1867, its mining industry is still at that stage of development which characterized the West 100 years ago when miners concentrated on high-grade lodes and rich placer deposits. Since World War II, however, there has been a noticeable increase of interest in the raw materials of the North. This concern has been most noticeable in Canada, Scandinavia and Russia, but it has been, and is being shown in Alaska. To the American mining industry, the potential importance of this State can be summed up by the question, "Can Alaskan mining compete successfully with those of other states and countries?" The answer revolves about the vital factors of geography, economics, and the political turmoil of the World. These aspects are among those discussed on the following pages in a series of articles by Alaskans and non-Alaskans alike. We invite you to read "Alaska: Regional Report."

Jan 12, 1961

By Robert H. Richards

The extent to which sizing by sieves should be carried, as a preliminary to the separation, by jigging, of minerals of different specific gravities, has been a matter of controversy for many years. The subject has been investigated by several authorities, yet the ground does not seem to have been completely covered, nor are the questions involved entirely settled. For my present purpose I shall refer to but three investigators—Rittinger, Munroe, and Hoppe. In seeking additional light, I have gone over part of the old ground which has been considered satisfactorily settled; and since these preliminary tests have thrown light on some points, they have been included in this paper. In the investigations here described, I have confined myself, for several reasons, wholly to small sizes—grains of 0.1 inch in diameter and less. Rittinger's work was mainly done upon larger sizes, and there is much need among millmen of information concerning the smaller sizes. Moreover, these sizes brought the investigation within the means at my disposal. The laws that have been claimed as the laws of jigging by the several authorities are: 1. The law of equal-settling particles. 2. The lam of interstitial currents. 3. The law of acceleration. 4. The law of suction. The first of these has been considered by investigators, generally, to be the most important of all, and the larger part of the work of jigging is thought to be governed by it. But that it does not cover the whole of jigging is clear to all; and to account for the increased efficiency which we may call the extra jigging-catch, the other three laws have been advanced. The investigation described in this paper was undertaken to determine, as far as possible, to what extent each of the four laws con-

Jan 1, 1895

By Edmund Davenport

THE specific aim of this work has been to study certain forms of internal deterioration which occur in tungsten filaments when subjected to high temperatures under various conditions, and to determine the cause of such deterioration. This would naturally lead to a consideration of methods of control or means of prevention of the phenomena. The deterioration was first noticed as a peculiar condition in the grain boundaries of certain tungsten filaments which had been burned? for long periods in lamps. In these cases it was noted that the grain boundaries contained a number of minute black dots which were at first thought to be non-metallic inclusions. It was demonstrated later that these dots or pits, as they were designated, could be readily produced by burning filaments in an atmosphere of flowing hydrogen. This method was convenient and adequate for the purpose, and was adopted for most of the work discussed in this paper. The evidence accumulated to date indicates that these pits are actually small voids between the grains. The purpose of this paper is to present- the information on this interesting subject gathered during a period of about 3 years. As applied to tungsten, the subject appears to be of considerable importance, experience having shown that this pitting ?is frequently associated with poor performance of filaments in lamps. The question has arisen as to whether these intergranular pits are peculiar to tungsten, or if they occur in all metals. If they are found iii all metals, the facts will be of considerable theoretical interest, as the material at the grain boundary plays an important part in most of the current theories of the properties of metals and alloys.

Jan 1, 1927

By J. E. Johnson

Charcoal-iron is quantitively so unimportant compared with coke-iron, that its qualitative importance for many industrial purposes is entirely unkriown to many coke-furnace-men, and to the great majority of the inembers of this Institute. To explain this qualitative importance, and explain some of the fact,ors that affect the quality, are the objects of this paper. A brief review of' the commercial conditions governing the charcoal-iron industry is a necessary preliminary to any adequate treatment of the subject. The advent of coke-iron, which transformed the whole iron industry commercially, left intact a limited production of charcoal-iron in the East and South, which has been conducted almays on the basis of high cost and high quality, with correspondingly high selling-price. In the Northwest, particularly in the Lake Superior district, the development has been along totally different lines, for which the close proximity of the great iron-ore deposits and the great forests of that region mere responsible. When the great white-pine forests were removed there were left behind large areas of hardwood and hemlock, to which little attention was paid in the prosperous years of the white-pine industry. But when the latter declined, the demand for lumber, and the presence of lumber-men, probably more skilled than any others in the world, caused the gradual introduction of these woods into commercial use. It was a matter of ancient knowledge that hardwood made an excellent charcoal, and to utilize the cordwood left after the saw-logs were removed, by converting it into charcoal and using it to smelt ore from the adjacent mines, mas an obvious step. In some cases the establishment of the furnace occurred in-

Jan 1, 1913