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By C. F. Kaiser, T. J. Roberts, I. A. Thomson

The Broken Hill Pty. Co. Ltd. grate-kiln pelletizing plant located at Whyalla, South Australia, produced a total of 250,000 tons of fluxed pellets during 1970. More than 180,000 tons were exported to Japan, while the remainder was used in B.H.P. Co. blast furnaces. The pellet plant treats high grade hematite ore fines and has a nominal capacity of 1.5 million tpy. The induration equipment includes a grate 12-ft 2-in. wide by 164-ft 1-in. long, a kiln 18-ft 6-in. diam by 118-ft 8-in. long, and a rotary cooler 50-ft mean diam by 7 ft wide. Operating problems encountered in the production of fluxed pellets are detailed. The most significant aspect of the trial was the increased production, from about 5100 tpd up to a maximum of 7100, brought about by the addition of artificial magnetite to the plant feed. Laboratory evaluation of fluxed pellets showed that pellets having a basicity ratio (CaO to SiO2) in excess of 1.2 have excellent physical qualities. Reducibility and compressive strength after reduction were both higher for these fluxed pellets than for normal acid pellets. Although it was not possible to publish blast furnace operating data, blast furnace trials on fluxed pellets indicated that production was higher and dust losses substantially lower, compared with similar operations on acid pellets.

Jan 1, 1973

By P. R. Bradley

NO thought had been given to deep level mining at the Alaska Juneau mine prior to 1930, but in that year a prospect winze was started and continued for 1000 ft. vertically below the main haulage or adit level. The point at which this winze was started was selected entirely by the prevailing physical conditions, such as proximity to established workings, convenience, and the presence overhead of a substantial pillar of dimensions sufficient to lo¬cate the sheave wheel and loading pocket. It was, therefore, with some surprise that the unusually high-grade ore found just below the collar of the winze persisted, with certain vari¬ations, to a full depth of 1000 ft. vertically. Likewise this unusually high-grade ore was found to persist on the various crosscuts driven on levels at 200-ft. vertical intervals. To be brief, this deep level work found richer ore than any yet found in the mine over like areas, and inasmuch as the area was sufficient to plan for extensive deep level mining, plans for such work were given extended consideration.

Jan 1, 1936

By H. M. Howe

One of the little electric-resistance magnesia crucible-furnaces which I designed for the metallurgical laboratory of the School of Mines of Columbia University is shown, in vertical section, of full natural size, in Fig. 1. The furnace itself consists of two semi-cylinders of magnesia, A A, with a cover of magnesia, B B, and a stopper, C, also of magnesia, which is perforated to admit the leads x, y, of a thermo-electric couple. The furnace is heated by the spiral of platinum wire, D D (entering and departing by the openings I and K), through which a current of any desired strength is passed, bringing it to incandescence, and to ally temperature, not above the melting-point of platinum, which may be desired. The crucible E, actually used in this furnace, is also of magnesia. I have heard of some unsuccessful attempts with furuaces of this general class, and have attributed these failures to the use of siliceous materials for the furnace-walls. Of course such a result is what we should expect, since the silica mould readily be electrolysed by the current, and the resultant silicon would alloy with platinum ; but the little magnesia furnace here clescribed seems to be wholly free from this objection. It has been used in my laboratory for some months, and temperatures, up to 1100° C, hare been developed in it over considerable periods of time—indeed, it has been held near 1400" C. for about two hours—without indication, thus far, of any deterioration of the platinum. In the section shown, F F are a pair of steel disks, bound together, but separated by the inverted thermo-junction, N, of the thermo-electric pyrometer. This arrangement permits the observation and record of retardations in the heating and cooling of F F—in other words, the determinations of the cooling curves of steel—a purpose for which the furnace has been used, thus far, more frequently than in the determination of meltingpoints. For the latter operation, however, it is also suitable.

Jan 1, 1902

By Haakon Styri

In discussion of Dr. Fitterer's paper on electrolytic separation of slag inclusions, some results from experiments on electrolyzing high-carbon steels at the SKF Research Laboratory were given. l We had been working for a number of years on chemical methods of separating the inclusions but could not find any solvent that would dissolve the steel without attacking some of the inclusions, particularly the sulfides in which we were mostly interested at the time, nor any that would dissolve all sulfide or silica in filings as fine as 300 mesh without attacking the iron. Electrolytic methods had also been tried without any real progress until we learned from the Bureau of Mines about the use of the collodion membrane around the anode. Our early difficulties were to some extent different from those of the Bureau of Mines, perhaps because of experimenting on steels of higher carbon content, but most of our difficulties were of the same nature as those of the Bureau. Formation of large quantities of basic hydroxides was traced to the use of impure and oxidized ferrous sulfate. To protect from oxidation from the atmosphere during electrolysis, after purer chemicals were obtained, a thin layer, 54 in. or less, of molten paraffin was poured over the surface of the cathode liquid, where it solidified. It was found desirable also to hold the cathode chamber slightly acid by initial addition of 0.1 per cent acid (sulfuric or hydrochloric) to prevent precipitation of the hydroxide. This acidity would decrease gradually and the cathode chamber would become neutral before the end of the electrolyzing. The increase in acidity in the anode chamber during our early experiments had appeared to cause attack of the precipitated sulfides in the residue, which originally was analyzed by volumetric method for sulfur, and for this reason a 10 per cent sodium citrate solution was substituted for the sulfate in the anode chamber. With the use of the more reliable Eschka method for sulfur determination (as in coke), there was however no serious attack on the sulfides in the anode chamber with a variety of different liquids, as shown in Tables 2 and 4. The Eschka method gives a higher sulfur value than

Jan 1, 1933

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

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

Jan 1, 1924

By Milton Lissberger

MILTON L. LISSBERGER, ? New York, N. Y.-Solder is a mechanical mixture of tin and lead, a fact which is susceptible of very simple demonstration. A bar of solder of a grade even as low as 30 per cent. tin and 70 per cent. lead, passed through a buffing machine, will show a surface practically identical with that of a bar of second-quality or reclaimed tin. The buffings, on chemical analysis, will prove to be almost pure lead. According to the best practice, solder is made in the following manner. Virgin pig lead is first melted, and when it is thoroughly liquefied, virgin pig tin is added, together with a small amount of flux; the latter is for the purpose of bringing to the surface the so-called "liver," consisting of impurities that may have remained in either the lead or the tin as a result of incomplete refining. The combined material, when completely liquid, is thoroughly stirred for some hours, and is then cast into small pigs. Just before casting, and continuously during this operation, the molten metal yields dross, consisting largely of the oxides of lead and tin; this should be carefully skimmed off. After the pigs have cooled, they are taken to a smaller kettle, remelted, and cast into the desired shape for use; or if wires, ribbons, etc., are to be made, the solder is cast into slugs suitable for extrusion and rolling. During this second operation, the skimming of dross should be even more carefully done than at first. Hand mixing has proved to be the only reliable method for the production of the best quality of solder, irrespective of its percentages of lead and tin. The best quality of solder is not necessarily that which contains the highest percentage of tin, but rather is that composition which performs best on the required piece of work. In order to produce

Jan 12, 1918

By B. W. Dyer

IN 1924, the Crescent Eagle Oil Co., while drilling the salt section of the Paradox formation in Grand County, Utah, encountered a salt that did not appear to be sodium chloride. This salt was analyzed and showed the presence of potash minerals, both sylvite (KC1) and carnallite (KMgC12.6H20). Because of the high potash content of the sample, there was considerable speculation: (I) as to whether the hole had been salted, and (2), if not, the extent, richness, and the depth at which the deposit occurred. The discovery caused a large amount of activity in the area. During the next few years, 68 potash prospecting permits were issued by the Government, 24 under the Act of 1917 and 44 under the Act of Feb. 7, 1927, each including about four sections of land. Several holes, all shallow, were drilled for potash. A number of holes were drilled for oil into the salt horizon and the cuttings collected at the oil wells were examined petrographically and chemically. The shallow test holes were not sufficiently deep to reach the potash horizon and revealed nothing of value, but several of the oil test holes gave some indication of where potash might be found. LOCATION AND GEOLOGY OF DEPOSITS The potassium and magnesium salts have been found in various places from the Denver and Rio Grande Western Railroad tracks about seven miles west of Thompsons, in eastern Utah, to Cane Creek, a tributary of the Colorado Rivera distance north and south of about 35 miles. In this locality, there appear to be five separate deposits: the Crescent Eagle area, which is in T. 22 S., R. 19 E.; the Salt Valley area, in the vicinity of the north-south line of T. 23 S., between R. 20 E. and R. 21 E.; the Seven Mile area, in the eastern part of T. 25 S., R. 2o E.; the Cane Creek area, on the Colorado River, in T. 26 S. and T. 27 S., R. 2o E. and R. 21 E.; and the Salt Wash area, in T. 22 S. and T. 23 S., R. 16 E. and R. 17 E. (Fig. I.) The Crescent Eagle and Salt Valley areas are in the Salt Valley anticline, some of the wells being in the fault graben and others outside. Structurally, the Salt Valley anticline is very complex, and can be described in general terms as a northwesterly plunging collapsed anticline about 15 miles long. In the Crescent Eagle area, the valley graben is about 1 mile wide and the salt probably forms a plug, the apex of which is in the vicinity of the Crescent Eagle well. Owing to the complex structure, there has been every opportunity for flowage in the salt to cause local thinning or thickening of beds. The regular succession of formations in the general area* is: [Cretaceous Mancos Dakota Jurassic Morrison Summerville Entrada Carmel]

Jan 1, 1945

By C. E. Jr. Reistle

ALL crude oils become more viscous when chilled, but the only oils that congeal and precipitate paraffin to such an extent as actually to cause production troubles are those that contain an appreciable amount of wax. In handling these oils of high wax content, three distinct problems may be encountered before the oil reaches the refinery. The first problem is the precipitation and accumulation of paraffin in the well, either in the oil string or on the face and in the pores of the sand. The second problem is the accumulation of paraffin and the congealing of oil in the transportation lines. The third problem is the precipitation of paraffin and the formation of tank bottoms.

Jan 1, 1927

NEW YORK SECTION Executive Committee, DAVID H. BROWNE, Chairman., JOHN H. JANEWAY, Vice-Chairman, F. E. PIERCE, Secretary, 35 Nassau St., New York, N. Y. P. A. MOSMAN, Treasurer, LEWIS W. FRANCIS, BENJAMIN B. LAWRENCE. At a meeting of the New York Section, held at the Machinery Club on Jan. 19, 1916, the topic, for the evening was The Problems of the Naval Consulting Board, on which board are four prominent members of the Institute. The speakers of the evening were W. L. Saunders, president of the Institute, Dr. L. H. Baekeland, and Commander A. B. Fry, chief of staff of the New York Naval Militia. After Chairman Browne had laid before the meeting certain business matters, he introduced President Saunders, who presided during the speech making and delivered the first speech. The letter from President Wilson to Mr. Saunders and the presidents of the other national engineering societies, inviting their cooperation in a scheme for mobilizing, as it were, the industrial capacity of this country, had just been made public (see a previous page of this Bulletin) and President Saunders described in considerable detail the origin, purposes, and scope, of the work to be undertaken in this direction. Each of the five national scientific societies is to select a representative from its resident members in every State of the Union, that is, the mining engineers will have 48 representatives, likewise the electrical engineers, the chemists, the civil engineers, and the mechanical engineers. Thus, there will be a representative body or board of five members in every State, one from each of the five societies or institutes. Each committee will investigate the manufacturing and producing possibilities in its own state, and will gather information as to the capacity of every industry which may be capable of supplying things that are needed for the sinews of war. Industrial preparedness means something more than mere capacity to make shells. The field covers food, clothing, hospital equipment, motors, animals, telephones, telegraph and railway accommodations, and a myriad of small details.

Jan 3, 1916

By William Glenn

In their account of chromium, Roscoe and Schorlemmer (Treatise on Chemistry, London, 1879) state that "In 1762 Lehmann, in a letter to Buffon, de nova minerœ plumbi specie crystalline rubra, described a new mineral from Siberia, now termed crocoisite." In 1786 Lehmann analyzed it (Nicholson's Jour., Dee., 1798) and found that it contained chiefly lead, and that the " mineralizers " were arsenic and sulphur. It was next examined in 1189 by Macquart and Vauquelin, who stated that it contained an intimate mixture of iron, alumina, and lead peroxide. The account of their work was published over the name of Macquart. Vauquelin (Louis-Nicolas) was a Norman peasant, who had studied in the village school, and at the age of fourteen was a laboratory-boy in a pharmacy at Rouen. Later, he found his way to Paris, and in 1789 was assistant to Fourcroy, a pharmacist and a teacher of note. It was here that he met Macquart, with whom he did the work on Siberian red lead, and at this time his friend Cheradame taught him his Latin.

Jan 1, 1896

By D. W. Gillmore, C. C. Wright

DEWATERING is a major problem in the preparation and utilization of fine-sized coals now being recovered in increasing amounts from colliery effluents, refuse banks, and silt ponds. Of the various methods which have, been proposed for dewatering fine coal, gravity drainage is probably the oldest and most widely used, and yet little information on this subject has been published. Consequently a laboratory investigation of gravity drainage phenomena was undertaken not only to provide basic data for predicting the drainage behavior of fine coals in cars, bunkers, basins, and silos, but also to obtain some understanding of the moisture retention properties of fine coal. Because of practical interest in the problem, a reproducible laboratory technique, which simulated plant conditions as closely as possible, was developed for the evaluation of drainage variables. The ap- paratus selected consisted of vertically-mounted lucite columns, nominally 4 to 8 ft in length and 2, 3 or 6 in. in diam; the bottom of the column was provided with a rubber stopper through which was inserted a -in. diam drainage tube; a wad of glass wool was placed on the upper part of this outlet tube to retain the coal and a plug was temporarily located at the lower end to prevent drainage during charging of the column, see Fig. 1. The most satisfactory testing procedure is as follows: 1—The fine coal, which has been thoroughly

Jan 1, 1953

By D. W. Gillmore, C. C. Wright

DEWATERING is a major problem in the preparation and utilization of fine-sized coals now being recovered in increasing amounts from colliery effluents, refuse banks, and silt ponds. Of the various methods which have, been proposed for dewatering fine coal, gravity drainage is probably the oldest and most widely used, and yet little information on this subject has been published. Consequently a laboratory investigation of gravity drainage phenomena was undertaken not only to provide basic data for predicting the drainage behavior of fine coals in cars, bunkers, basins, and silos, but also to obtain some understanding of the moisture retention properties of fine coal. Because of practical interest in the problem, a reproducible laboratory technique, which simulated plant conditions as closely as possible, was developed for the evaluation of drainage variables. The ap- paratus selected consisted of vertically-mounted lucite columns, nominally 4 to 8 ft in length and 2, 3 or 6 in. in diam; the bottom of the column was provided with a rubber stopper through which was inserted a -in. diam drainage tube; a wad of glass wool was placed on the upper part of this outlet tube to retain the coal and a plug was temporarily located at the lower end to prevent drainage during charging of the column, see Fig. 1. The most satisfactory testing procedure is as follows: 1—The fine coal, which has been thoroughly

Jan 1, 1953

The question, Who won the war?, has been the text for innumerable newspaper, and magazine articles, the answers running from "bread and butter" to "poison gas," in a material sense, and from the "Y. M. C. A." to the "boys in the front lines," humanly speaking. Personally, I think the margin by which success was secured was so narrow that none of the complex, interdependent factors could have been .spared, and that, as Admiral Sampson said after the battle of Santiago: "There is glory, enough for all." But if any one human factor can be said to have been absolutely indispensable, I think all will agree that it was the engineer. The engineer, as a rule, is a modest fellow, so modest in fact and so averse to publicity of any kind that, referring to him as a class, he was hardly occupying the place he should in public estimation before the war. By way of illustration, in the early history of a mine in Bisbee, the chief owner was also the proprietor of a saloon and spent most of his time there. When asked why he did not pay more attention to the mine, lie replied: "Oh! I can hire a boy to look after that; it takes a man to run this bar." Comparisons of the position and pay of engineers with other occupations are sometimes made to show that the engineer is not getting all that he should, considering the time of preparation and the qualifications required. Perhaps at least a part of the cause may be his aloofness from many of the practical affairs of everyday life. Whether he won the war or not, the part played by the engineer has certainly placed him on a sort of pedestal in the public estimation at present and it is very desirable to keep him there and maintain the position he has made for himself.

Jan 9, 1919

By Benjamin L. Miller, Charles H. Breerwood

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 limestone 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. Origin of Limestone Disregarding details and unusual types concerning which often there is insufficient evidence and considerable difference of opinion, limestones have been formed by the precipitation of calcium carbonate from solution through the action of organisms, both plants and animals, or in a limited number of instances by chemical reactions without the intervention of living forms. Some of the organisms extracted the calcareous material in order to build up hard structures, either as bony skeletons or as coverings (clams, snails, etc.), whereas others in their life functions emitted substances that resulted in the precipitation of the soluble constituents outside the organisms themselves. In some instances the organisms utilized only calcium carbonate but in some cases other compounds as well were precipitated. Various materials have been found in the hard parts of animals, and for that reason it is almost impossible to find a pure natural limestone; that is, one composed entirely of CaCO3.

Jan 1, 1938

By Charles H. Breerwood, Benjamin L. 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 limestone 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. Origin of Limestone Disregarding details and unusual types concerning which often there is insufficient evidence and considerable difference of opinion, limestones have been formed by the precipitation of calcium carbonate from solution through the action of organisms, both plants and animals, or in a limited number of instances by chemical reactions without the intervention of living forms. Some of the organisms extracted the calcareous material in order to build up hard structures, either as bony skeletons or as coverings (clams, snails, etc.), whereas others in their life functions emitted substances that resulted in the precipitation of the soluble constituents outside the organisms themselves. In some instances the organisms utilized only calcium carbonate but in some cases other compounds as well were precipitated. Various materials have been found in the hard parts of animals, and for that reason it is almost impossible to find a pure natural limestone; that is, one composed entirely of CaCO3.

Jan 1, 1938

By Lawrence Addicks

SOME three years ago the smelter connected with the Chrome, N. J., refinery of the United States Metals Refining Co. found itself embarrassed y constantly increasing piles of unsmelted blast-furnace flue dust. The charge was fine and 10 to 15 per cent. of it was blown over into the flue. Sulphur was at that time too scarce to make the sintering of the finer part of the charge attractive, and raw-ore smelting in a reverberatory with a partly oxidized charge. was not to be thought of. A great many schemes were considered, including leaching, blowing into the converters, and briquetting, the problem finally narrowing down to blast roasting and nodulizing. It was found by experiment that blast roasting would not yield a satisfactory sinter without the addition of coke dust or sulphide fines to augment the fuel value of the flue dust, and on this account, together with the low first cost of a kiln, the latter was decided upon. A couple of tons of flue dust Were tried out in the experimental kiln in the laboratory at Yorktown, Va., of J. H. Payne, who acted as consulting engineer in this connection. This kiln was approximately 2 ft. in diameter and 20 ft. long and Was fired with fuel oil. A run of several hours yielded excellent nodules. The kiln showed no tendency to build in and form "nose rings" and gave a fuel consumption of 50 gal. of oil per ton of flue dust. There was no indication of any stack loss. The roasting was strongly oxidizing. A study of what full-size kilns were doing on cement clinker and on nodulizing pyrites cinder indicated that a 60 by 6 ft. kiln would certainly not consume over half of the oil per. ton of flue dust shown on the test and as fuel oil at that time Was selling around 2 1/2 c. per gallon it was decided to let it go at that.

Jan 7, 1914

By J. H. Frye, R. M. Treco

ONE of the chief hindrances to an understanding of the hardness of solid solutions is the sparsity of suitable hardness data. There is great need of a large body of hardness data obtained from many different alloys of high purity by identical testing methods and corrected to correspond to a single grain size. A considerable amount of such data has been obtained by means of the Meyer analysis on copper-rich and silver-rich solid solutions. There are enough of these data to permit comparison of numerous alloys at equal solute concentration in these two solvents, but only in a few cases is it possible to construct hardness-concentration curves for any given alloy. Therefore additional hardness work on most of these alloys is desirable. The primary solid solutions of silver with cadmium, indium, tin, or antimony as solute are of special interest, since all elements are from the same period of the periodic table and since, as shown previously,1 the hardening effect of equal percentages of these solutes is proportional to the lattice expansion produced by them. This paper presents the relation between hardness and concentration in the silver-antimony system from very dilute to nearly saturated solutions of antimony in silver. EXPERIMENTAL PROCEDURE Alloys were made from silver, 99.99 per cent pure, and antimony, 99.975 per cent pure. Silver and antimony were placed in graphite crucibles that had an ash content of less than 0.75 per cent. These metals were melted and allowed to solidify in a vacuum, which, after melting was complete, was usually equivalent to 3 mm. Of mercury. A high-frequency furnace was used. The ingots so obtained were worked and annealed to lessen segregation and to control grain size. Annealing was done in evacuated and sealed glass tubes. Hardness measurements on specimens from these ingots were by means of the Meyer analysis.3,4 Using a 4-mm.. ball, impressions were made under seven loads from 25 to 400 kg. The diameter of impression made under each load was measured. This enabled calculation of the constants in the well-known formula of Meyer. L=ad¬n where L = load, d = diameter of impression, a = a constant, n = a constant The Meyer hardness is defined as P = L/(1/4pd2) or P = 4adn-2/p Meyer hardnesses corresponding to d = 1 and to d = 4 are of especial interest, since the first corresponds to comparatively slight plastic deformation and the second to the maximum plastic deformation producible by penetration of the ball. These

Jan 1, 1944

By James F. Kemp

Discussion of the paper of D. Foster Hewett, Bulletin To. 27, March, 1909, pp. 291 to 310. JAMES F. KEMP, New York, N. Y.:-Mr. Hewett's paper is one of exceptional interest, because it not only adds an important contribution regarding one of the rarer, valuable elements, but also because it introduces compounds hitherto unknown and in associations no less novel. While we have occasionally dis¬covered and recorded asphaltite in metalliferous deposits, for example in the Joplin and Granby districts, we have not seen a metallic ore in a deposit essentially asphaltite. The source and method of introduction afford a subject well worth serious reflection. Vanadium was first discovered and recognized as a distinct element in the slags obtained in smelting the titaniferous magnetites at Taberg, Sweden. For a long time, therefore, we looked upon the titaniferous magnetites as its hone. Analyses proved, years ago, that it was present in the ores of this type in New Jersey and in the Adirondacks. It was quite rarely determined, but when looked for it was, I think, invariably found, although the Amount seldom exceeded 0.5 per cent. of V,05., In just what combination it exists in the titaniferous ores is uncertain. One might imagine V2O3 replacing some of the Fe2O3 of magnetite; or, since in the lead series vanadates and phosphates are closely akin, one might wonder if a lime-vanadate could take the place of apatite. Yet no lime-vanadate has been found in nature, and apatite itself is usually rare in the titaniferous ores. When percentage-curves are plotted for a series of analyses of the ores, the line of vanadic oxide shows a curious sympathetic behavior with the line of chromic oxide;' but the data are somewhat limited, and no compound has sug¬gested itself which throws light on the matter. Dr. W. F. Hillebrand has discussed the occurrence and dis-

Oct 1, 1909

By W. C. Clarke

An empirical study of the nature of the embrittle-ment which occurs in martensitic and semiaustenitic precipitation hardening stainless steels upon exposure at temperatures of from about 550" to 875°F has been undertaken. This work was aimed at determining cazusation and means of controlling this phenomenon. A commercial copper bearing precipitation hardening alloy was used as a basic material for study. The effect of heat treatment variables was studied as was the effect of variations in analysis. It is concluded from the evidence that martensitic and semiaustenitic precipitation hardening stainless steels are subject to 885°F ernbrittlement similar to that observed in the straight chromium stainless steels. A characteristic of precipitation hardening stainless steels which has limited their use in certain applications is that they embrittle when held at temperatures in the range of from about 550" to 900°F. This is true to a more or less degree in all currently available alloys, either the basically martensitic type or the semiaustenitic type. The rate of embrittlement varies markedly with exposure temperature, being low at 550" to 600°F and in-creasing as the temperature increases. In spite of this embrittlement, these alloys with their unique combination of high mechanical strength, reasonable toughness, and good corrosion resistance are used in many hundreds of applications. Nevertheless, there are potential applications where the embrittle-ment described is a limiting factor. The purpose of this investigation was to study the embrittlement of these alloys and to find a way to control or eliminate it. GUIDELINES USED IN PRESENT WORK The work reported in this paper is based on a study of 17-4 PH*, a very widely used alloy. It has been used *Trademark of Armco Steel Corp., licensor. in pressurized water and boiling water atomic reactors operating at about 550°F for a number of years. As the life of such equipment is extended or operating temperatures are raised, the possibility of embrit-tlement becomes of increasing concern to materials engineers. Much investigation work was done with respect to the use of 17-4 PH at 550°F. K. C. Antony' states "Such estimation" (of an activation energy for the diffusion of chromium in iron) "would indicate W. C. CLARKE, Jr. is Senior Research Engineer, Advanced Materials Division, Armco Steel Corp., Baltimore. Md. This manuscript is based on a talk presented at the symposium on New Developments in Stainless Steel, sponsored by the IMD Corrosion Resistant Metals Committee, Detroit, Mich., October 14-15, 1968. significant secondary aging is improbable at temperatures less than 700°F within normal component service life". This statement is modified however by the recognition of the accelerating tendencies of applied stress and internal stress as well as the possible effect of irradiation. In this investigation of 17-4 PH, the H 1100 (1900°F-1 hr oil quench or air cool + 1100°F-4 hr-air cool) condition was used, partly because this condition is normally used in atomic reactors. As shown later, the precipitation hardening temperature has no real bearing on the rate of embrittlement. An exposure temperature of 800°F was selected since embrittlement at 800°F is rapid, permitting development of relative data in time periods of 400 to 500 hr. For those not familiar, a nominal present day analysis of 17-4 PH is: C Mn P S SiCrNiCuCbN 0.04 0.30 0.015 0.015 0.60 16.00 4.30 3.25 0.23 0.030 TYPICAL BEHAVIOR OF 17-4 PH Figs. 1 and 2 show the behavior of a commercial heat of 17-4 PH under the conditions defined. Characteristically, 800°F exposure causes a rapid drop in Charpy V-notch impact strength. Tensile and yield strengths gradually increase and a gradual loss of elongation and reduction of area occur, accompanied by an increase in hardness. Notched tensile strength increases to 125 hr exposure and then sharply decreases after exposure for 500 hr. The notched vs un-notched tensile ratio remains virtually constant to exposure for 125 hr (1.67 to 1.56) but drops to 1.15 after 500 hr. Tensile ductility is not alarmingly affected even after much longer exposure times than these. For example, samples aged at 1100°F for 1 hr exposed at 800°F for 4000 hr showed a drop in elonga-tion of from 13 to 11 pct and in reduction of area of from 58 to 37 pct. Notched impact is the property SmIgth KSI 3JJ[/__________^UTS-Nrteh 260 ;/- 240 —^ 200 UTS-Smooth________._, o ioo mo Sob" m Too Hours Exposure Fig. 1—Effect of exposure at 800°F for various times on notched tensile strength and smooth tensile and 0.2 pct yield strength of 17-4 PH in the H 1100 condition.

Jan 1, 1970

By Gilbert E. Doan

IN a technical civilization, that is. one whose major difference from past civilizations is its enormous development of technology, in transportation, communication, labor saving, centralized control, and mass production, it is natural that the most critical problems should be those that arise out of technologic advances; it is natural also that a. man who understands these advances should be chosen as the leader to meet these problems. This was done in the selection of Herbert Hoover as President of the United States. Mr. Hoover was a good, and perhaps a great President. But he was not a great politician and that ensured his defeat when a crisis came.

Jan 1, 1939