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Ninetecn papers and a round table. as follows: The Future of the American Iron and Steel Industry (Howe memorial Lecture), by Zay Jeffries; Rote of Carbon Elimination and Degree of Oxidation of metal Hath in Isasic Open-hearth Practice. 11, by ,Alexander L. Feild; A New Method for determining lron Oxide in Liquid Steel, by C. H. Herty. Jr., J. M. Gaines. Jr., H. Freeman and M. W. Lightner; I'racticsl Obarrvntions on Manufacture of basic Open-hearth, High-carbon Killed Steel, by W. J. Itcagan; Production of Gray lron from steel Scrap in the Electric Furnace, by T. F. Baily; reclaim ing Steel-foundry Sanda, by A. H. Dierker; Influence of Rate of Cooling on Dendritic Structure and Microstructure of Some Hypocutectoid Steel, by Albert Sauveur and C. H. Chou; Transformation of Austcnite at Constant Subcritiral Temprratures, by I?. S. Dnvenport and E. C. Bain; Progress Notes on the Iron-silicon Equilibrium Diagram, by Bradley stoughton and S. Greiner; Influence of Nitrogen on Special Steels and Some Experiments on Case-hardening with Nitrogen; by Shun-ichi Satoh; Production and Some properties of Large Iron Crystals, by N. A. Ziegler: Tensile Properties of Rail and Other Steels at Elevated Temperatures, by John R. Freeman, Jr. and G. Willard Quick; Endurance Properties of Steel in Steam, by T. S. Fullcr; Development of Casing for Deep Wells; a Study of Structural Alloy Steels, by F. W. Bremmer; Electrolytic Iron from Sulfide Ores. by Robert D. Pike, George H. West, L. V. Steek, Ross Cummings and B. P. Littlc; Sintering Limonitic Iron Ores at Ironton, Minnesota, by Perry G. Harrison; Concentration of the mesabi Ilematites, by E. W. Davia; Resistance of Iron Ores to Decrepitation and Mechanical Work, by T. L. Joseph and E. P. Barrett; Experiments Demonstrate Method of Producing Artificial Manganese Ore, by T. L. Joseph, E. P. Barrett and C. E. Wood; Iron Ore Round Table.

Jan 1, 1930

NORTH AMERICA ALASKA Anchorage.-Ames, M. B. Culver, H. W. Fiedler, H. L. Geehan, R. V. Langneas, O. O. Layfield, R. A. Parent, A. Saarela, L. H. Strandberg, H. Candle.-Robbins, J. S. Chichagof.-Russell, J. C. College.-Fox, E. F. Joesting, H. R. Lyman, R. F. Smith, M. C. -Wilcox, H. G. Douglas.-Cahill, W. E. Fairbanks.-Adams, J. M. CANADA Canadian Army Overseas.¬Ball, H. D. Bridges, O. Butterill, H. J. M. Lane, H. C. Millar, W. A.

Jan 1, 1942

By Harmel A. Dawson, Robert A. Wilson

First the basic steps to determine the values present and the minerals involved which are the basis for the metallurgical testing are presented in this paper. Next, choosing the process or processes indicated for treating an ore are discussed. This is followed by the test procedures used, the results of which will indicate amenability to treatment. These test procedures have been developed, used and proven effective in laboratory evaluations relative to plant processing. Special, uncommon processing is beyond the scope of the paper. Evalutation of test results and incorporation into the preliminary and final flow sheet for plant design are discussed. The value of a flow sheet, with material and water balances, to plant design is shown.

Jan 1, 1978

By William M. Shepard

The Tintic mining districts of central Utah com- prise one of the major silver-lead producing areas in the United States. Ore valued at nearly $450 million has been produced from these districts since the initial discoveries, in 1869, of veins cutting the Silver City monzonite stock. Subsequent production from the famous manto-type "ore runs", which characterize the Main Tintic district, was followed during the past 40 years by discovery of the blind orebodies of the East Tintic district, including the famous Tintic Standard mine and the most recent discovery, the Burgin mine, currently being brought to full production by Kennecott Copper. The occurrence of blind orebodies of exceptional size and grade in both the Main and East Tintic districts has made this area a field laboratory of major importance for the study of geochemical dispersion halos and alteration features associated with known ore, and has led to the discovery of additional concealed orebodies. The larger share of the basic data-gathering and interpretation has been done by members of the U.S. Geological Survey who have been studying the Tintic mining areas since before the turn of the century. These studies have been supplemented and expanded by the geological staffs of the local operating mining companies, by exploration geologists and by students.

Jan 4, 1966

By D. H. Gieskieng

THE advent of curved jaw crusher wearing plates made an approach other than segmental layout analysis desirable for prediction of capacities. For some time it had been known that the drawing board capacities of crushers using these plates had to be considerably modified by complicated experience factors to achieve agreement with results. Because these apparent capacities could be readily increased severalfold by minor crushing chamber shape changes, it was necessary that the utmost precaution be taken in predicting capacities of jaw plates modified for nonchoking, special wear characteristics, or any other reason. To this end the laboratory and field tests outlined by the author in a previous paper1 were made on Blake-type jaw crushers. The results of these tests were summarized in a simple first degree equation applicable to crushers using either straight or curved jaw plates. This equation first outlines the maximum capacity potential of a given crusher, then reduces this figure in accordance with installation circumstances by means of a realization factor. It was found subsequently that this equation, with the addition of an eccentric throw factor, is applicable to standard types of single-toggle or overhead eccentric jaw crushers as far as maximum capacity potential is concerned. However, these crushers have realization factor curves somewhat different from those outlined for the Blake type. While this paper is concerned principally with standard type single-toggle crusher capacities, the evaluation of data obtained with these machines is simplified by comparative reduction to the 10 x 7 in. Blake-type equivalents upon which the summary of the preceding paper was made. Convertibility of data from one type of crusher to the other also tends towards confirmation of both. The agreement of these data is sufficient to be considered complimentary. Consequently the feed factors, f, previously reported for Blake crushers are slightly adjusted to an average with the single-toggle crusher results. Blake-type equation: C = f.d.w.y.t.n.a.r [I] Single-toggle type equation: C = f.d.w.y.t.n.a.e.r [21 where C is the capacity in short tons per hour through the crusher, f is a feed factor, dependent upon the presence of fines in the feed, and the surface character of the jaw plates used. Values of f : Smooth Plates Corrugated Plates With normal fines 0.0000414 0.0000319 Fines scalped out 0.0000368 0.0000252 Large pieces only . 0.0000312 0.0000215 d is the apparent density of the broken product in pounds per cubic foot. (If the true specific gravity of the feed is known, 40 pct voids may be assumed and d becomes 37.4 times sp gr). w is the width of crushing chamber in inches. y is the openside setting of the crusher, in inches. In the case of corrugated jaw plates it is measured from the tip of one corrugation to the bottom of the valley opposite. t is the length of jaw stroke in inches at the bottom of the crushing chamber. It is the difference between open and close-side settings. n is rpm, or crushing cycles per minute, a is the nip-angle factor. It is unity for 26" and 3 pct greater for each less nip-angle degree. A nip-angle of 20" has an a value of 1.18, and an angle of 30" has an a value of 0.88, see Fig. 1. r is the realization factor. It is unity for perfectly uniform choke feeding and usually less for actual operating conditions according to the method of feeding used and the probabilities of hang-ups involving the size of feed and crusher opening. Approximate values are given by the curves in Fig. 2. These values are further reduced by intermittent feeding, e is the throw or diameter of gyration of the single-toggle crusher eccentric in inches. As evident in Fig. 1A, variation of feed size will generally have little effect on nip-angle if both jaw plates have flat areas. Jaw plates having continuous curvature, as in Fig. 1B will have different nip-angles, depending upon the size of feed. For test work as described in this paper this effect was accounted. For general compilation of capacities for average feeds it is suggested that the nip-angle be taken at the various settings computed, at an arbitrary level, such as is indicated in Fig. 1C. Data Evaluation To bring the Blake and single-toggle type crusher capacity test results to common terms for evaluation, all data are converted to terms of 10 x 7 in. Blake-type performance at conditions of 100 lb per cu ft, 10 in. chamber width, 250 rpm, 0.65 in. stroke, 3-in. openside setting, and 18° nip-angle. (The nip-angle of the 10x7 in. Blake is 18° at 3-in. setting.) The single-toggle crusher performances are also divided by the eccentric throw to bring this effect to unity. As outlined,' laboratory and field tests made on Blake-type crushers ranging from 10 x 7 in. to 60 x 48 in. were summarized along the foregoing conditions of speed, stroke, etc. This resulted in groups of data which correspond to feeds with fines, feeds

Jan 1, 1952

By Hans Conrad, W. D. Robertson

FORMAL theories of yielding and flow have been developed to describe thermally activated plastic flow in metal crystals.'-" hey are all based on Becker's' original idea that thermal fluctuations aid the applied stress in overcoming internal barriers to flow and lead to the following relation. where j is the strain rate; C is a constant which includes a frequency factor, the entropy, the number of flow units, and the amount of strain associated with each successful fluctuation; E(T) is the activation energy associated with flow, and is a decreasing function of the applied stress, 7; k is Boltzmann's constant; and T is the temperature in OK. The various theories differ mainly in the model chosen and in the nature of the relationship between the applied stress and the activation energy. Beckerl and Orowan' suggest a relationship of the form E a(Ti — t)2, where .ri represents the stress required for flow without the aid of thermal fluctuations; Kauzmann,3 Cottrel1,5 and Seeger6,7 suggest E a(t — t) ; Fisher8 suggests E while Cottrell and Bilby4 suggest a more complex relationship between E and 7. Additional data are needed to test these various theories., esweciallv- in view of Dorn's9 ork. which indicates that the activation energy for creep is independent of the stress and strain. The present paper presents the stress-strain data derived from incremental loading of magnesium single crystals in tension and direct shear, in the temperature range of 78" to 364°K. Incremental loading was employed in order that the creep component of the strain could be determined. Stress-strain curves of aluminum10-13 and copper" single crvstals. derived from incremental loading tests, have been found to be in agreement with those obtained by the more conventional constant strain rate or loading rate tests. Two types of tests were conducted in the present investigation: 1) tests in which the temperature was maintained constant throughout the entire

Jan 1, 1958

By Colin M. Sargent

THE electron diffraction pattern as seen in the electron microscope represents an approximately plane section of the reciprocal lattice. Identifying the zone axis of a diffraction pattern is often laborious for a crystal of low symmetry, especially if several crystal orientations are present. A program has been written in FORTRAN II (Version 2) for the IBM 1620 which will assist in plotting out reciprocal lattice sections. The calculation is performed by choosing a zone axis [uvw] and determining the d spacings and angle between the planes (Ow - v) and (wO - u). (This procedure is varied slightly for zone axes with Miller indices equal to zero.) Cartesian coordinates for the reciprocal lattice points are then calculated for these planes and for (ww— [u + v]). Any reciprocal lattice points within the parallelogram formed by the origin and these three points are then computed. The input and output are best described by use of an example (Monoclinic ZrO2) used in the author's work. Input consists of two cards: 1) The crystal parameters: a, b, c, a, 8, y, e.g., 5.1477, 5.2030, 5.3156, 90.000, 99.380, 90.000. 2) Three numbers, D, E, F, e.g., 5, 3, 3.0710-the first is the limit of the sum (u + v + w) considered; the second limits the absolute value of u, v, and w to (E- 1), e.g., 2, so that zones (221) would be the highest order considered in this example; the third, F, is the required constant, yL. Output is in the format shown in Table I. The reciprocal lattice sections may then be plotted on standard graph paper and compared with the unknown diffraction pattern. (Note that no attempt has been made to deal with systematically absent reflections.) A card deck for the program is available from Colin M. Sargent, ARZ, W-PAFB, Dayton, Ohio, 45433.

Jan 1, 1969

By Richard Hamburger

The purpose of this paper is to call attention to certain methods which will shorten and simplify the calculation of plane tri-angulation. These methods, though not new & do not appear to have been properly publicized in the United States. The cotangent (or tangent) solution of a triangle permits calculation of coordinates in a smooth series of operations of the calculating machine with a minimum of notation. The semigraphical solution permits the simultaneous solution of a number of intersections, at one station, without the added burden of solving additional triangles. This in turn encourages more numerous field checks and more complete office computation than would normally be undertaken. RICHARD HAMBURGER, Junior Member AIME, is Junior Engineer, Inspiration Consolidated Copper Co., Inspiration, Arizona. TP 2798 A. Discussion (2 copies) may be sent to Transactions AIME before March 31, 1950. Tables I and I1 show the distinct advantage which the combined use of the cotangent and the semi-graphical solutions hold over, what might well be called, the standard solution. It will be shown that the positions for the entire net in fig. 1 may be calculated without computing any distances, thus saving much computation. (2) Comparison of Cotangent and Standard Solutions: To compare the cotangent method with the standard method, the notation involved in the solution of triangle 1-X-4, fig. 1, by both methods is shown. Fig. 2 shows the given information, that is, the coordinates and azimuths of Stations 1 and 4, and angles of the triangle or the azimuths from Stations 1 and 4 to Station X. (Azimuths are used here because the author feels that they are easier to handle, but bearings may be used by those who prefer them). It will be seen from the above comparison that the advantages of the cotangent solution of a triangle are: (a) rapidity, (b) full use of the calculating machine, (c) the small number of

Jan 1, 1951

By Richard Hamburger

(1) Introduction: The purpose of this paper is to call attention to certain methods which will shorten and simplify the calculation of plane tri-angulation. These methods, though not new,',2 do not appear to have been properly publicized in the United States. The cotangent (or tangent) solution of a triangle permits calculation of coordinates in a smooth series of operations of the calculating machine with a minimum of notation. The semigraphical solution permits the simultaneous solution of a number of intersections, at one station, without the added burden of solving additional triangles. This in turn encourages more numerous field checks and more complete office computation than would normally be undertaken. RICHARD HAMBURGER, Junior Member AIME, is Junior Engineer, Inspiration Consolidated Copper Co., Inspiration, Arizona. TP 2798 A. Discussion (2 copies) may be sent to Transactions AIME before March 31, 1950. Tables I and I1 show the distinct advantage which the combined use of the cotangent and the semi-graphical solutions hold over, what might well be called, the standard solution. It will be shown that the positions for the entire net in fig. 1 may be calculated without computing any distances, thus saving much computation. (2) Comparison of Cotangent and Standard Solutions: To compare the cotangent method with the standard method, the notation involved in the solution of triangle 1-X-4, fig. 1, by both methods is shown. Fig. 2 shows the given information, that is, the coordinates and azimuths of Stations 1 and 4, and angles of the triangle or the azimuths from Stations 1 and 4 to Station X. (Azimuths are used here because the author feels that they are easier to handle, but bearings may be used by those who prefer them). It will be seen from the above comparison that the advantages of the cotangent solution of a triangle are: (a) rapidity, (b) full use of the calculating machine, (c) the small number of

Jan 1, 1951

By Harry H. Angst

The history and efficiency of 40-ton capacity dump trucks for surface waste removal at the New Cornelia opencut copper mine, at Ajo, Ariz., are summed up in this paper. Tabulations of truck performance, together with detailed cost figures, prove the value of truck transportation for certain special operations at a large mine. Emphasis is given to the fact that truck transportation not only reduces the haulage costs but also reduces the breaking ground and shovel-loading costs per ton. The New Cornelia opencut copper mine is in the desert. The climate is ideal for seven months of the year, but the five summer months are uncomfortably hot. 'She elevation is 1820 ft. above sea level and the annual rainfall is approximately 6 inches. The ore body is a monzonite-porphyry deposit. The waste-rock capping consists of hard rhyolite, conglomerate and porphyry. All the material is hard and cannot be excavated without blasting. The rhyolite and conglomerate waste is very blocky. The weight of the rock in place is 2.16 tons per cubic yard. The average mine production per day is 22,090 tons of 012 and 18,000 tons Of waste rock, the latter consisting of surface rock and material within the ore body too low in grade to send to the concentrator. The rock is loaded by electric shovels with 4½-cu. yd. dippers. The primary transportation of ore to the concentrator and waste to the dumps is by 30-yd. dump cars and oil-burning steam locomotives; therefore truck haulage of waste is a minor factor of the New Cornelia operation. However, as New Cornelia was one of the first mines to use large-capacity dump trucks for haulage, the results obtained are of interest. Equipment On the south side of the New Cornelia is a hill rising about 500 ft. above the normal surface elevation, roughly 1000 ft. in diameter at its base, called locally Arkansas Mountain peak. Exploratory drilling in this area developed additional ore that could be made accessible for open pit operation only by moving the mountain face a maximum distance of 400 ft. to the south. The slope of the mountain adjacent to the pit averaged 35°, and the small area involved precluded the use of train haulage for the removal of the 4,000,000 tons of waste estimated above the normal pit elevation. A study of dump-truck haulage at Boulder Dam and San Gabriel Dam led to the decision to use large-capacity end-diii~lp trucks rather than smaller trucks, for the following reasons: I. The truck would have to withstand the impact of hard, heavy chunks, some of them weighing as much as 10 tons, which would be dumped from the 4½-cu. yd. dipper. 2. The coarse, rocky, abrasive material would soon damage a light truck body. 3. The body of a small truck could not be efficiently loaded with coarse rock.

Jan 1, 1943

By Harry H. Angst

The history and efficiency of 40-ton capacity dump trucks for surface waste removal at the New Cornelia opencut copper mine, at Ajo, Ariz., are summed up in this paper. Tabulations of truck performance, together with detailed cost figures, prove the value of truck transportation for certain special operations at a large mine. Emphasis is given to the fact that truck transportation not only reduces the haulage costs but also reduces the breaking ground and shovel-loading costs per ton. The New Cornelia opencut copper mine is in the desert. The climate is ideal for seven months of the year, but the five summer months are uncomfortably hot. 'She elevation is 1820 ft. above sea level and the annual rainfall is approximately 6 inches. The ore body is a monzonite-porphyry deposit. The waste-rock capping consists of hard rhyolite, conglomerate and porphyry. All the material is hard and cannot be excavated without blasting. The rhyolite and conglomerate waste is very blocky. The weight of the rock in place is 2.16 tons per cubic yard. The average mine production per day is 22,090 tons of 012 and 18,000 tons Of waste rock, the latter consisting of surface rock and material within the ore body too low in grade to send to the concentrator. The rock is loaded by electric shovels with 4½-cu. yd. dippers. The primary transportation of ore to the concentrator and waste to the dumps is by 30-yd. dump cars and oil-burning steam locomotives; therefore truck haulage of waste is a minor factor of the New Cornelia operation. However, as New Cornelia was one of the first mines to use large-capacity dump trucks for haulage, the results obtained are of interest. Equipment On the south side of the New Cornelia is a hill rising about 500 ft. above the normal surface elevation, roughly 1000 ft. in diameter at its base, called locally Arkansas Mountain peak. Exploratory drilling in this area developed additional ore that could be made accessible for open pit operation only by moving the mountain face a maximum distance of 400 ft. to the south. The slope of the mountain adjacent to the pit averaged 35°, and the small area involved precluded the use of train haulage for the removal of the 4,000,000 tons of waste estimated above the normal pit elevation. A study of dump-truck haulage at Boulder Dam and San Gabriel Dam led to the decision to use large-capacity end-diii~lp trucks rather than smaller trucks, for the following reasons: I. The truck would have to withstand the impact of hard, heavy chunks, some of them weighing as much as 10 tons, which would be dumped from the 4½-cu. yd. dipper. 2. The coarse, rocky, abrasive material would soon damage a light truck body. 3. The body of a small truck could not be efficiently loaded with coarse rock.

Jan 1, 1943

Conservation and Survey Division, University of Nebraska, Lincoln, Nebr. G. E Condra, State Geologist. Publications in geology of tlie Conservation and Survey Division are as follows: No 1, Stratigraphy of the Pennsylvanian System in Nebraska, by G. E Condra, 75 cents; 3, Correlation of tlie Pennsyl-

Jan 1, 1933

Arizona E. P. MATHEWSON, Chairman W. V. DECAMP. First Vice-chairman H. W. ALDRICH, Second Vice-chairman E. D. GARDNER, Secretary-Treasurer, Care U. S. Bureau of Mines, Tucson, Ariz. F A. AYES, J. P. HODGSON W L DU MOULIN WILLIAM KOERNER Boston Meets first Monday each winter month GEORGE B WATERHOUSE, Chairman GEORGE A PACKARD, Vice-chairman F. LEROY FOSTER, Secretary-Treasurer Room 8-219, Mass. Inst. of Tech , Cambridge, Mass. F K MORRIS F S MULOCK

Jan 1, 1923

New York Holds monthly meetings, except June, July and August J E SPURR, Chairman A D BROKAW, Vice-chairman SIDNEY ROLLE, Vice-chairman M H MERRISS, Secretary-treasures, Nichols Copper Co, 25 Broad St, New York M F CHASE KARL HOFFMAN Boston Meets first Monday of each winter month C R HAYWARD, Chairman E C GEITHER, Vice-chairman D H McLAUGHLIN, Secretary-treasurer, Rotch Bldg, Harvard Univ Cambridge, Mass GEO H GILMAN GEO A PACKARD

Jan 1, 1923

By Edward B. Cook

INTRODUCTION. THE installation of the Gayley Dry-Air process appealed specially to the management of the Warwick Iron & Steel Co., for the. reason that for fifteen years records had been kept at the works of the company, showing the amount of water entering the furnace in the form of aqueous vapor, and careful observations had been made of its effect upon the working of the furnace. Some years had proved much worse in their effect than others, on account, not only of excessive moisture, but also of great variation in the moisture from day to day, and sometimes within a few hours. It had been found impossible to. make a satisfactory percentage of high-silicon foundry-iron in summer, even on high fuel; and for some years the endeavor had been made so to arrange the sales that, during July and August, only a small percentage of the iron produced would be required to carry more than 2 per cent. of silicon. Our larger furnace, running on basic iron, year after year, produced in February a tonnage 20 per cent. higher than in August, on a much lower fuel-consumption, while, at the same time, the summer months were marked by ? messes," tuyeres closed by slips, and other irregularities, constituting serious additional business losses. It will be easily understood, therefore, that the records made at the Isabella furnace after the installation of the dry blast in 1904 possessed special interest, and were closely watched by us. On the basis of our own experience, we argued that if the moisture could be kept low, and also uniform, the cost of installation would be more than justified. The subject was brought before our Board of Directors in the fall of 1905; and in the spring of 1906 it was decided to install a plant of sufficient capacity to treat 70,000 cu. ft. of air per min., an amount

Nov 1, 1908

AIME 1953 DIRECTORY SUPPLEMENT OFFICERS AND COMMITTEES OF LOCAL SECTION; COUNCIL OF SECTION DELEGATES Linwood Thiessen, Chairman H. D. Vaughan, Vice-Chairman John H. Melvin, Secretary EXECUTIVE COMMITTEE L. E. Thelin, Connecticut J. B. Cunningham, Arizona W. L. Penick, San Francisco G. L. Yates, Kansas DELEGATES Adirondack - C. DeWitt Smith '54 Alaska - Robert 11. Chapman, ?54 Arizona J. B. Cunningham, '53 Black Hills - Sidney M. Runke, '54 Boston -R'. Schuhmann, Jr. ?54 Carlsbad Potash - W. P. Wilson, '54 Central Appalachian - Charles T. Holland, '54 Chicago - H. A. White, '54 Cleveland - Milton Tilley, '54 Colorado - J. Paul Harrison '54 Columbia - Harold Kirkemo, '54 Connecticut - Lewis E. Thelin, ?53 Dallas - Kenneth F. Anderson, '54 Delta - Roy S. Sullins '54 Detroit - F. P. Bens, '53 East Texas - Joseph A. Morris, '54 El Paso Metals - E. M. Thomas, '54 Florida - W. O. McClintock '54 Fort Worth - Ray Elner, '51 Gulf Coast - H. E. Treichler, '53 Kansas - G. L. Yates, '53 Lehigh Valley - H. R. Gault '54 Lima, Peru - R. P. Koenig, ?54 Lou-Ark - A. H. Crawford. '53 Mexico - W. G. Kane, '54 Mid-Continent - J. H. Beesley, '53 Minnesota - J. R. Stuart, '54 Montana - F. W. Strandberg, '53 Nevada - Albert Silver,'53 New York - P. Malozemoff, '54 North Pacific - A. H. Mellish, '54 North Texas - K. F. Anderson, '54 Chio Valley - J. H. Melvin, ?53 Oklahoma City - Charles Miller, '53 Oregon - T. C. Matthews, '54 Penn. Anthracite - D. C. Helms, '54

Jan 1, 1953

By D. K. Deardorff, Earl T. Hayes

An improved technique is described for the accurate determination of melting points of metals in the temperature range 1500' to 2500°C. The improvements consist of gradient heating and refinements in cavity preparation to obtain true black-body conditions. The melting point of hafnium, as determined by this method, is set at 2222°±30°C. This is over 200°C higher than one of the values reported earlier. Discrepancies in the previously reported values for the melting point of hafnium are explained. The melting points of zirconium and titanium are found to be 1855O±15OC and 1668°±10°C, respectively. Reproducibility of results was ±3OC. PRIMARILY, this report is being made to correct a 1975o±25oC1 value for the melting point of hafnium, and to present an improved method for melting point determination. As a matter of interest, the technique was also applied to determining the melting point of zirconium and titanium. There is a wide difference in the melting point of hafnium as reported by competent investigators. DeBoer and Fast' reported a value of 2230°±500C, and later work of McPherson, as reported by Aden-stedt, placed the melting point at 1975o±25oC. Zwikker" calculated that the melting point was 2430°C. In resolving this discrepancy, improvements were made in the procedure for determining the melting points of refractory metals in the range 1500" to 2500°C. Special techniques are necessary to determine the melting point of these metals accurately. Since the metals oxidize in air above 900oC, the determinations must be carried out in an inert gas or vacuum. Also, every known refractory contaminates them to some extent. In addition, the attainment of true black-body conditions is always difficult. DeBoer and Fast actually determined the melting point of Hf-Zr as-deposited iodide process alloys and extrapolated to 100 pet Hf. McPherson employed a tungsten wire suspension similar to that described by Schramm, Gordon, and Kaufmann,1 and used hafnium metal produced by the iodide process. There was no apparent reason for the wide spread in melting points, since the quality of the metal was very good and the work was under the direction of highly competent investigators. Retracing some of this work revealed one understandable error in the case of hafnium, and led to development of an improved technique for determining melting points of reactive metals in the range 1500" to 2500°C. Material Crystal bar hafnium, zirconium, and titanium were used for this work, with analyses as shown in Table I. The hafnium was of the highest purity that has been prepared, though not as pure as the zirconium and titanium. At the instigation of the Pittsburgh Area Office of the AEC, a special lot of Hfo2 was purified, converted to the tetraflouride, and bomb-reduced with calcium, all at the Iowa State College Laboratories. This crude hafnium metal was then refined by the iodide process at the Foote Mineral Co. All specimens were cut with a Sic wheel, ground, pickled, and dried carefully before use. Procedure General Tungsten Suspension Method—In this method, a small specimen is suspended by a fine tungsten wire in a slender, induction-heated tungsten or tantalum cylinder, all under vacuum. The melting point is determined by heating the specimen slowly while observing it with an optical pyrometer focused upon a portion of the specimen that radiates as a black body. This means that there should be no reflected radiation, either from colder objects near the pyrometer or from hotter surfaces. The induction heater would be the only hotter object and, if it is slender enough, the specimen will attain the same temperature. Often a slender hole is drilled into the specimen as a source of black-body radiation. This was the general method used by McPherson in obtaining his value of 1975°C for the melting point of hafnium. In trying to repeat this work, it was found that the points of contact between the

Jan 1, 1957

Institute of Metals Division Iron and Steel Division Extractive Metallurgy Division J C Kinnear, Jr, President A W Thornton, Past President W R Hibbard, Jr, Vice-President R W Shearman, Secretary-Treasurer AIME, 29 West 39th Street New York 18, N Y Board of Directors J B Austin, D L Clark, H B Emerick, T D Jones, H H Kellogg, C T Marshall, E E Schumacher, C S Smith, J D Sullivan

Jan 1, 1957

LIMA (PERU) Established May, 1952 (Official year begins in June) Luncheon meetings third Wednesday monthly Ernesto A Baertl, Chairman Arthur C Hall, Chairman-elect Raymond R Beard, 1st Vice-Chairman Edgardo Portaro, 2nd Vice-Chairman Walter E King, Secretary-Treasurer Av Santa Cruz 331 San Isidro, Lima, Peru Alberto E Brazzini, Asst Treasurer Daniel M Rodriguez, Asst Secretary Robert P Koenig, '56, Section Delegate Arthur C Hall, Alternate Section Delegate

Jan 1, 1955

JOSEPH W. RICHARDS, Chairman. J. E. JOHNSON, JR., Vice-Chairman. ARTHUR S. CALLEN, Secretary, 453 Chestnut St., So. Bethlehem, Pa. SUB-COMMITTEES IRON ORE DWIGHT E. WOODBRIDGE, Chairman. ERNEST F. BURCHARD, WILLIAM KELLY, CHARLES F. RAND, FELIX A. VOGEL. BLAST FURNACES II. A. BRASSERT, Chairman. WILLIAM H. BLAUVELT, AMBROSE N. DIEHL, JAMES GAYLEY RICHARD V. McKAY. STEEL WORKS HENRY D. HIBBARD, Chairman. GUILLIAEM AERTSEN, C. F. W. RYS, .1. S. UNGER. FRANK D. CARNEY, A. A. STEVENSON, WILLIAM It. WALKER. MECHANICAL TREATMENT CHARLES A. BUCK, Chairman. ROBERT W. HUNT, GEORGE MESTA, FREDERICK W. WOOD.

Jan 6, 1915