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By D. M. Spratt, O. R. Bell

In Australia's remote northwest are located the operations of Cliffs Robe River, one of the world’s largest iron ore projects. initial project cost was $US300 million and required the construction of a deepwater port, two towns for 3000 people, a 105 MW power station, and 170 km of railroad, all in harsh, arid country over 1300 km from the nearest industrial center. The ore occurs as goethite cappings on scattered mesas and averages 57% iron. All aspects of the project are reviewed from pre-operational research, through project construction to current operation.

Jan 1, 1982

By S. R. Krom

In connection with perfecting a system of pneumatic concentration I had in view the improvement of machines for crushing and pulverizing ores. A study of the whole subject convinced me that the principle upon which the construction of the Blake crusher, and that of rolls, is based, possessed the mechanical elements which, if perfected and simplified, would make these machines the successful rivals of every other device. It is well-known that until very recently the stamp-battery held undisputed possession of the field; and mill-men and mill-builders almost universally believed that stamps would not be superseded by any other machine for fine crushing. The first step to drive stamps from the field was the introduction of rollers in the Bertrand and the Mt. Cory mills. In both of these mills the great superiority and economy of a system of crushing with rollers instead of stamps has been fully demonstrated. While perfecting the rollers, I had the fact confronting me that they had frequently been tried without success. In fact, the universal opinion prevailed that rollers could be used only for coarse, and not for fine crushing. The secret of the difficulty I discovered to lie in the imperfect and weak character of the rolls heretofore used, due to a misconception of the requirements for a machine for such work, and a failure to appreciate the advantages of continuous, rolling, crshing- surfaces, operating on the toggle-lever principle, which gives the greatest crushing pressure with the least power. expended, and the minimum of wear.

Jan 1, 1886

By R. W. Raymond

The death of the eldest of the honorary members of the Institute was not unexpected. Ritter von Tunner had never recovered from the effects of a paralytic stroke received in 1892, and when the same enemy struck again in February of this year the blow was plainly mortal. He passed away June 9th, gently and without pain. Thus ends a career of great distinction and fruitfulness, crowned with fame and love. This pioneer of the age of iron and steel had lived so long and wrought so much that the present generation could scarcely recall the whole category of his services. There can be no more appropriate use of the pages of these Transactions than to honor them with a record of such a life and work, for the inspiration of other lives to other labors. Peter Tunner was born May 10, 1809, near Peggau, in Styria.† In the same province, his grandfather, Josef Tunner, had purchased a primitive nail-forge and enlarged it to a ham

Jan 1, 1898

By C. A. Kroetz, A. J. O’Neal

The Long Island Lighting Co. has operated an extensive monitoring system for over three years. Nearly 900,000 separate pieces of information have been recorded for a land area of some 600 sq miles, 15 miles north to south by 40 miles east to west. The data are composed of about a half million sulfur dioxide measurements at various locations, 290,000 of which were by the West-Gaeke method, about 160,000 pieces of weather data, and 220,000 measurements of sulfur dioxide as emitted from each of the power plant stacks on the system, all measured on an hourly basis and stored on computor cards and tapes. The computor has been programmed to collate stack emissions, weather information, and ground level sulfur dioxide measurements. The analysis shows that emissions from tall stacks do, indeed, contribute very little to ground level sulfur dioxide. For example, LILCO shows that its Northport plant contributes less than 2 ppb, hourly annual average. They also state that the plant converted to 100% natural gas or shut down, would reduce ground level sulfur dioxide by no more than 2 ppb.

Jan 1, 1973

By John A. Church

THE Lake Superior blast-furnaces probably represent the maximum economy of fuel possible in this country. They smelt an ore which is very rich and easily reducible, and as the small amount of gangue present is not all silica, but in part a silicate, the amount of limestone required is a minimum. The average yield of the ore treated at six furnaces was 63 per cent., and the average quantity of limestone 179 pounds per ton of pig. The fuel used is charcoal, so burned as to retain most of the combustible volatile part, which, before the utilization of furnace-gas, was burned away. With these conditions it is not surprising that the Lake Superior charcoal practice is extraordinary in almost every respect. In any scientific discussion of American furnace work, the establishments there will be found at the head of the list, and they work under conditions which are extremely favorable for careful study. The Bay Furnace, near Marquette, has the honor of carrying "the broom" for the largest daily make. With a capacity of 1908 cubic feet it has, for months together, produced 29 tons of pig, graded at

Jan 1, 1876

By Douglas A. Karvonen

INTRODUCTION Although the economy in the Province of Saskatchewan has historically been agriculturally oriented, a major source of wealth has been realized through natural resources such as petroleum and natural gas, coal and uranium and since the 1960's - potash. Potash or potassium chloride, in the form in which it is presently produced in Saskatchewan, is used primarily as fertilizer, a source of potassium, one of three essential elements required for healthy plant growth, with about 5% of production sold to the chemical industry for use in such products as soap and liquid detergent, glass and ceramics, textiles and some pharmaceuticals. Saskatchewan is estimated to have approximately 40% of known world potash reserves and its ten active mines account for some 25% of annual world production. POTASH CORPORATION OF SASKATCHEWAN In an effort to guarantee a fair and lasting economic benefit to the Province of Saskatchewan, the Potash Corporation of Saskatchewan (PCS) was created on February 4, 1975 through an Order-in-Council under the Crown Corporation's Act and later on April 1, 1976, the Potash Corporation Act provided for its continuation. PCS was given the mandate to acquire ownership of a significant portion of the potash mining capacity in Saskatchewan and to establish an organization capable of operating the facilities, marketing the product, and conducting all of the other activities necessary for a successful corporation competing in the world potash industry. The corporation is the largest potash producing and selling organization in the Western World - or third largest in the world. (See also Figure 1). PCS through its wholly-owned subsidiary, PCS Mining, has acquired a whole or partial interest in five geographically distinct producing properties or divisions, representing today more than 40% of Saskatchewan's potash producing capacity. The acquisition of each division was followed by a program designed to exploit and maximize the particular opportunities at each minesite for increased production. To that end, PCS Mining has taken an active lead in expanding to meet future demand and has implemented expansion programs at all properties except for its Esterhazy Division where it has a long-term processing agreement with International Minerals & Chemical Corporation (Canada) Limited. Through its wholly-owned subsidiaries, PCS Mining, PCS Sales and PCS Transport, this provincial crown corporation has the ability to operate as a producer and marketer of Saskatchewan's potash. In certain instances PCS, the parent company, assists in the financing of various projects undertaken by the subsidiaries and in other cases the subsidiary involved arranges its own financing. POTASH RESERVES As a background to the specific issue of financing, it is helpful to describe briefly the nature of the deposit which supports the industry - our collateral, if you like. The potash beds underlying Saskatchewan are sedimentary rock deposits formed by the gradual evaporation of an inland sea during the Middle Devonian period roughly 400 million years ago. Now known as the Prairie Evaporite, this formation stretches from North Dakota and Northeast Montana through Southern Saskatchewan into North-Central Alberta. These beds lie at mining depths ranging from 950 - 1000m (3,000 ft) below the surface, where conventional mining methods can be used, and to 1,650m (5,000 ft), where solution mining must be

Jan 1, 1985

By Seymour Fiekowsky, Alvin Kaufman

Taxes are compulsory charges levied by a government for its support. They are usually paid to support the general services provided by government rather than special services (such as safety inspection). The latter are normally supported by user charges often called license fees. Taxes are used by national governments not only to raise money but also as a part of fiscal policy. As such, taxes are used to stimulate or deflate the economy, as an incentive to save or invest, as a means of allocating national resources, and as a means of redistributing income. In our discussion, we will deal only with those facets of the subject that relate specifically to the mineral industry. In doing so we will deal with taxes levied on all industry in a generalized way and only insofar as it affects our industry, but at some length on those portions of the tax system related directly to the mineral industry. It is not our intent to provide a "cookbook" for computing taxes, but rather to present some of the policy issues that bedevil those who must develop our tax policies. MINERAL TAXES The mineral industry is subject to the full range of taxes levied by governments. These include taxes on income, property, and sales, as well as excise and severance taxes. The latter are somewhat similar to a royalty in , that such taxes are levied either ad valorem or per unit of output. Severance taxes most commonly are charged to oil and gas output, although coal, salt, sulfur, and iron ore production also have been taxed in this manner. The major governmental advantage of the severance tax is the administrative ease of collection. On the other hand, it poses an addition to cost independent of profitability. As a consequence, the severance tax can cause premature abandonment if mineral product prices do not rise sufficiently to cover it. Such a rise may not occur if differential tax rates are levied by the various states. Property taxes normally are levied on all property owners, including mineral owners. The major difficulties in this kind of tax, in so far as mining is concerned, are erratic valuation coupled to the inherent problems involved in assessing a property where the extent and richness is chiefly unknown. The impact of these taxes, including state income taxes, is reduced somewhat, as they are usually deductible from gross income as a business expense with a consequent lowering of national income taxes. The net cost of severance, property, sales, and state or local

Jan 1, 1976

By F. R. Jones

T Tahawus, N. Y., National Lead Co. operates the MacIntyre development. Here the world's largest titanium mine produces 5200 long tons of ore per day and pours 8000 long tons of waste rock over its dumps. Concentrated ilmenite is sent by rail to National Lead Co. pigment plants, and a second product, magnetite, is sold to steel producers in raw form or is agglomerated and shipped as sinter. Several earlier attempts had been made to produce iron from the deposits, which have been known since 1826. These attempts failed, chiefly because of titanium impurity. In 1941 the present owners re-established the operation for production of war-scarce ilmenite, and the impurity became the main product.

May 1, 1956

By C. R. Van Hise

[Concluding Contribution of Prof. Van Hise to the Discussion of his Paper, and Others on the Same General Subject, presented at the Washington Meeting, February, 1900 (see Ram., xxx., 27, 177, 323, 424, 578) ; also of the contributions of Vogt, De Launay, Beck, Lindgren, Kemp, Rickard, Bain, Keyes, Collins and Adams, presented at the Richmond Meeting, February, 1901, and to be printed in the present volume.] In June, 1900, shortly after my paper was published in the Fransactions, I made a briefer statement* before the Western Society of Engineers covering the same ground, which, in certain respects, is somewhat of an improvement. For instance, instead of using the terms descending and ascending &th reference to the waters resulting in the two concentrations, my modified statement is as follows: " The first concentration of many ore-deposits is the work of a relatively deep water-circulation, while the reconcentration is the result of reactions upon an earlier concentration through the agency of a relatively shallow water-circulation. Commonly the deep water-circulation is lacking in free oxygen, and contains reducing agents, and the shallow water contains free oxygen. The deep water is therefore a reducing, and the shallow water an oxidizing agent."† Of the papers upon ore-deposits which, in vol. xxx. of the Fransactions, follow my own, or which were presented at the Richmond meeting, a considerable number are wholly con-

Jan 1, 1902

By A. D. Smigelskas, E. O. Karenna

This is the third paper in a series on the diffusion of zinc in alpha brass.' At the time of the first paper it was accepted that diffusion in a substitutional type of solid solution depended upon an equal interchange of solute and solvent atoms across the diffusion interface (or past a given lattice reference point). Discrepancies in the size of the areas under the diffusion curves on each side of the interface, if observed, were explained on some other basis than the fact that the solute atoms might cross the diffusion interface without an equal number of solvent atoms diffusing across the interface in the opposite direction. The second paper presented evidence indicating that zinc atoms in alpha brass diffuse across the interface more rapidly in one direction than the copper atoms diffuse across the interface in the opposite direction. This phenomenon forced the interface to move in the opposite direction of the diffusion of zinc atoms to provide space for the additional zinc atoms dissolved in the alpha brass. That the interface and columnar grain structure on one side would remain intact during this mass movement was not expected; how ever, it is gratifying that they did. While the evidence was sufficiently satisfying to the author, it was decided that additional experiments were in order to prove that zinc diffuses more rapidly than copper in alpha brass. It is the purpose of this paper to present the results of these experiments. Procedure A bar of 70-30 wrought brass was selected, to avoid the relatively large volume change in going from beta to alpha brass as in the previous investigation. A bar 7 in. (18-cm.)* long and about 3/4 in. (1.9 cm.) wide was surface ground and polished with abrasive paper on plate glass to 0.4184 0.0002 in. (1.062j + 0.0005 cm.) thick. Six0.00j-in. (0.013-cm.) diameter molybdenum wires, chosen because of their very low solubility in coppcr and alpha brass, were strctched lengthwise along each of the two plane surfaces. Glass tubes placed at right angles to the wires every 1/2 in. held the wires tightly against the brass. The sample was then emersed in an acid copper sulphate plating bath and electroplated to a depth of about 0.020 in. (0.050 cm.) copper on all sides. The glass tubes were no longer necessary to hold the molybdenum wires in place and were removed. The sample was then electroplated to a depth of

Jan 1, 1947

By E. O. Karenna, A. D. Smigelskas

This is the third paper in a series on the diffusion of zinc in alpha brass.' At the time of the first paper it was accepted that diffusion in a substitutional type of solid solution depended upon an equal interchange of solute and solvent atoms across the diffusion interface (or past a given lattice reference point). Discrepancies in the size of the areas under the diffusion curves on each side of the interface, if observed, were explained on some other basis than the fact that the solute atoms might cross the diffusion interface without an equal number of solvent atoms diffusing across the interface in the opposite direction. The second paper presented evidence indicating that zinc atoms in alpha brass diffuse across the interface more rapidly in one direction than the copper atoms diffuse across the interface in the opposite direction. This phenomenon forced the interface to move in the opposite direction of the diffusion of zinc atoms to provide space for the additional zinc atoms dissolved in the alpha brass. That the interface and columnar grain structure on one side would remain intact during this mass movement was not expected; how ever, it is gratifying that they did. While the evidence was sufficiently satisfying to the author, it was decided that additional experiments were in order to prove that zinc diffuses more rapidly than copper in alpha brass. It is the purpose of this paper to present the results of these experiments. Procedure A bar of 70-30 wrought brass was selected, to avoid the relatively large volume change in going from beta to alpha brass as in the previous investigation. A bar 7 in. (18-cm.)* long and about 3/4 in. (1.9 cm.) wide was surface ground and polished with abrasive paper on plate glass to 0.4184 0.0002 in. (1.062j + 0.0005 cm.) thick. Six0.00j-in. (0.013-cm.) diameter molybdenum wires, chosen because of their very low solubility in coppcr and alpha brass, were strctched lengthwise along each of the two plane surfaces. Glass tubes placed at right angles to the wires every 1/2 in. held the wires tightly against the brass. The sample was then emersed in an acid copper sulphate plating bath and electroplated to a depth of about 0.020 in. (0.050 cm.) copper on all sides. The glass tubes were no longer necessary to hold the molybdenum wires in place and were removed. The sample was then electroplated to a depth of

Jan 1, 1947

By Charles D. Russell, L. H. Jenks, W. J. Leas

A detailed description is given of an experimental method for determining relative permeability of porous media to gas. Results are presented for natural and synthetic cores. The experimental data for two and three phase systems are compared. The reproduci-bility of the equilibrium gas saturation ii demonstrated and the effects due to a variation in rate of gas flow are discussed. An attempt is made to correlate total permeability and rock textural factors with relative permeability to gas. Capillary pressure curves obtained simultaneously with the relative permeability curves are shown to be equivalent to those obtained in conventional displacement cells. INTRODUCTION The advances in petroleum reservoir technology during the past decade have made increasingly apparent the desirability of a simple, rapid, reliable metliod for obtaining relative permeability data on small cores. Such data are needed in order to study fluid mechanics in porous media and for the more refined reservoir behavior prediction calculations now under development. The early experimental work in this field was done by Wyckoff and Botset1 who measured relative permeabilities for gas-liquid mixtures flowing through

Jan 1, 1950

By Thomas Fraser

Because of the present interest in the subject of sulfur in coal and its removal, such information as is available in the coal-washing literature on the various factors that determine the adaptability of a coal for wash- ing have been collected and are presented here together with some observations based on results of experimental work carried out in the coal-washing laboratory of the mining department of the University of Illinois, and investigative work at Illinois nrasheries in connection with the work on reduction of the sulfur content of coal, being carried on at the Urbana Station of the U. S. Bureau of Mines. This investigative

Jan 1, 1920

By I. Iwasaki, K. A. Smith

A chlorination process for treating metal sulfide flotation concentrates is described. The process involves low temperature chlorination combined with sulfur chloride conversion and selective oxidation to produce nonferrous metal chlorides, elemental sulfur, and ferric oxide in a three-stage fluidized bed reactor. The nonferrous metal chlorides may then be water leached, separated, purified, and electrolyzed to recover copper and nickel metals and to regenerate chlorine for recycling.

Jan 1, 1986

By M. A. Torcaso, P. Raimondi

The distribution of the oil phase in Berea sandstone resulting from increasing and decreasing the water saturation by imbibition was investigated Three types of distribution were recognized: trapped, normal and lagging. The amount of oil in each of these distributions was determined as a function of saturation by carrying out a miscible displacement in the oil phase under steady-state conditions of saturation. These conditions were maintained by flowing water and oil simultaneously in given ratios and by using a displacing solvent having essentially the same density and viscosity as the oil. A correlation shows the amount of trapped oil at any saturation to be directly proportional to the conventional residual oil saturation Sor The factor of proportionality is related to the fractional permeability to the water phase. Part of the oil which was not trapped was displaced in a piston-like manner (normal part) and part was eluted gradually (lagging part). The observed phenomena are more than of mere academic importance. Oil which is trapped may well provide the fuel essential for forward combustion and thus be beneficial. On the contrary, in tertiary recovery operations, it is this trapped oil which seems to make current techniques uneconomic. INTRODUCTION A typical oilfield may initially contain connate water and oil. After a period of primary production water often enters the field either from surrounding aquifers or from surface injection. During primary production evolution and establishment of a free gas saturation usually occurs. The effect and importance of this third phase is fully recognized. However, this investigation is limited to a two-phase system, one wetting phase (water) and one non-wetting phase (oil). The increase in water content of a water-wet system is termed imbibition. In a relative permeability-saturation diagram such as the one shown in Fig. 1, the initial conditions of the field would be represented by a point below a water saturation of about 35 per cent, i.e., where the imbibition and the drainage curves to the non-wetting phase nearly coincide. When water enters the field the relative permeability to oil decreases along the imbibition curve. At watered-out conditions the relative permeability to the oil becomes zero. At this point a considerable amount of oil. called residual oil, (about 35 per cent in Fig. 1) remains unrecovered. Any attempt to produce this oil will require that its saturation be increased. In Fig. 1 this would mean retracing the imbibition curve upwards. In addition, processes like alcohol and fire flooding, which can be employed at any stage of production, involve the complete displacement of connate water and an increase, or imbibition. of water saturation ahead of the displacing front. Thus, in several types of oil production it is the imbibition-relative permeability curve which rules the flow behavior. For this reason a knowledge of the distribution of the non-wetting phase, as obtained through imbibition, whether "coming down" or "going up" on the imbibition curve, is important.

Jan 1, 1965

By F. N. Rhines

I. An Outline of the Theory of the Sintering of Pure Metal Powders SINTERING may be defined as the process by which powders bond themselves into coherent bodies, usually, although not necessarily, under the influence of pressure and elevated temperature. For the sake of clarity and simplicity, the present survey will exclude from consideration the sintering of mixed or alloyed powders, with attendant complications, but at the risk of overlooking information of general applicability. Sintering in the presence of a liquid phase is thus automatically eliminated. The sintering of alloys involves much additional subject matter and deserves separate consideration. Since the literature of the subject is extensive and widely scattered, it will not be feasible to consider the contributions individually. Instead, the subject matter will be classified according to experimental observations and theory, and will be presented in summary form. It should be noted that the appended list of references does not constitute a complete bibliography; it includes only those works quoted below. More extensive bibliographies are included in several of the references; see particularly references 7, q, 28, 34, 38, 50, 52, 54 a "Bibliography on Powder Metallurgy" published by the Library of Congress and a pamphlet published by the Metals Disintegrating Co. entitled "The Field of Powder Metallurgy and Bibliography." II. Summary of Experimental Observations The following classified list is composed of general statements of established fact derived from the experimental results reported in the published literature. A few contested observations are included, because of their potential importance; these are labeled as such. Any satisfactory and complete theory must be capable of explaining all of the uncontested facts. Obviously, some important facts may be missing from this list and these may hold the key to the correct explanation of the sintering process, but the possible lack of such material should not deter attempts to understand the subject on the basis of what is available here. A. The Initial Bond at Room Temperature a. To a limited extent uncompressed powders and massive metals adhere at room temperature.28 Clean tin powder forms a weak "cake" on standing at room temperature, the strength increasing with time. Clean gold surfaces adhere on light contact,"' as do those of many other substances, including nickel." b. Upon compression the strength of the bond is increased progressively.28 There is a limit of pressure

Jan 1, 1946

By C. R. Taylor, John Chipman

THE study of chemical reactions of liquid steel and basic open-hearth slag involves a complex slag system of at least eight important components, and often a number of others. In initiating an experimental program on the equilibrium relationship of slag and metal, it became evident that but little progress could be expected in the interpretation of the complex slags until an understanding had been gained of the simpler liquid systems composed of a limited number of slag constituents. The simplest system that in any way resembles open-hearth slag must contain lime, silica and iron oxide. Attempts to produce in an induction furnace slags containing only these constituents have met with serious limitations because of the solubility of refractories in the slag. Thus in acid-lined furnaces the slag is always saturated with silica and consequently contains between 48 and 63 per cent of this component. In basic-lined furnaces an undesired additional component, magnesia, is introduced to the extent of some 3 to 15 per cent, depending upon the acidity, sometimes with disastrous results to the furnace. Thus in a magnesia-lined furnace, Fetters and Chipman1 found it impossible to prepare slags in which the ratio (CaO + MgO)/SiO2 was less than that corresponding to the metasilicate (approximately 0.8: I). Between this composition and that of the true acid slags lies a field of composition about which very little is known and which cannot be explored by any ordinary means. This circumstance, as well as the desire to study the more basic slags in the absence of magnesia, calls for the development of a method by which slags may be brought into equilibrium with molten metal without coming in contact with refractory. Such a technic has been provided by the rotating induction furnace developed by Barrett, Holbrook and Wood.2 Three modifications of the rotating furnace were described by these authors. The first was essentially a rotating refractory cylinder containing the magnesia crucible, which was itself heated by a graphite crucible. In the second, only the magnesia crucible rotated, the cylindrical graphite heater being stationary. In the third, the coil and crucible revolved, and the metal was heated directly by induction. EXPERIMENTAL METHOD Furnace The furnace used in this investigation differed from previous designs and may be considered a fourth modification of the original rotating furnace. Its essential features are shown in Fig. I. The outer case A is a fire-clay flue liner for control of the atmosphere. The top B and base C are alberene stone. The coil supports D are of "Formica," a material formed from phe-

Jan 1, 1942

By F. E. Crane, H. A. Kendall, G. H. F. Gardner

Two effects of a difference in density may be observed in miscible displacement. As the difference is increased from zero there is first a change in mode from multiple fingers to a single finger. A further increase results in a more rapid growth of the single finger. Miscible displacement with multiple fingers has been discussed by Blackwell, et al, whereas miscible displacement with a single finger has been discussed by Craig, et al. In the present paper experiments are described which bridge the gap between these extreme cases. INTRODUCTION Craig, et al,1 investigated the effect of gravity on frontal displacements for circumstances in which the gravity forces were significant. Blackwell, et a1,2 dealt with the other extreme in which gravity forces were negligible. The considerable difference between their results is illustrated in Fig. 1 where the breakthrough recoveries are plotted against the mobility ratio. The experiments described in the present paper were conducted to examine how the transition from the one extreme case to the other occurs when the gravity forces are gradually reduced. The transition is well illustrated by the production history after breakthrough. Fig. 2 shows how the number of pore volumes which must be injected at a constant rate to displace 98 per cent of the original fluid depends on the gravity force. For each mobility ratio there is a transition range, and a very significant change in the number of pore volumes occurs when this range is traversed. This range of the gravity force is physically linked with the formation of viscous fingers. A single finger is predominant for larger gravity forces; a multiplicity of fingers is formed for smaller gravity forces. Improved recovery and the occurrence of multiple fingers is concomitant with a large increase in the amount by which the fluids are mixed within the porous medium. The transition range depends on all the dimension-less groups which characterize the problem; but this dependence has not been exhaustively studied as yet and only fragmentary results are discussed in this paper.

By O. N. Carlson, K. E. Solie

The brittle-ductile transition temperatures of single and poly crystalline chromium metal were studied as a function of nitrogen concentration and chromium nitride distribution. It was observed that In recent years there has been an increasing interest in chromium-base alloys for high-temperature applications. The principal disadvantages, however, have been the difficulties of fabrication and the design problems associated with a material of such limited ductility. Various studies have been the effects noted in the poly crystalline material are essentially reversed in the single crystals. These observations are discussed in terms of existing theories for the brittleness of chromium. conducted recently directed toward a determination of the cause of this brittleness and to find ways for minimizing its effects. Allen et al.,' Wain Abrahamson and rant,' and weaver4 have carried out studies on the effects of interstitial impurities on the brittle-ductile transition of chromium metal of various degrees of purity. These investigations have shown that oxygen has little or no effect on the transition temperature of chromium in all conditions studied but that carbon increases the transition temperature under all conditions tested. Nitrogen was found to increase the transition temperature in the wrought condition and in the quenched or cast conditionS but reportedly has no effect in the furnace-cooled condition.

Jan 1, 1964

By T. S. Fuller

VARIOUS phases of the embrittlement of solid copper containing oxygen by the action of reducing gases at high temperatures through the work of many experimenters are familiar to readers of metallurgical literature. In 1900, Heyn1 recorded observations of copper being heated in hydrogen with the development of fine cracks, the result of the formation of steam within the metal through the action of hydrogen on the copper oxide usually found in copper. Archbutt,2 in 1905, published the results of experiments, showing that all oxygen can be removed from copper by heating to redness, for several hours, in hydrogen. Intercrystalline cracks and extreme brittleness developed. Archbutt attributed the brittleness to the reduction of oxides present in the copper. Bengough and Hill,3 in 1910, encountered the now well-known embrittlement at the outset of their investigation and stated in their paper: It soon became evident that the effect of any heat treatment depended largely on the presence or absence of reducing gases in the atmosphere of the furnace, as well as on its temperature. Hence it became necessary to adopt a somewhat elaborate scheme of heat treatment. The authors found embrittlement in separate experiments due to both hydrogen and carbon monoxide and concluded that: "The gases ruin the alloys after being heated to about 650° C. in their presence."

Jan 2, 1926