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By Eugene Coste

In a recent paper' I took exception to the opening paragraph of Mr. Hill's paper, in which he says:— " In endeavoring to interpret the geological occurrence of oil, the geologist is confronted by the fact that science has not yet solved the problem of its origin, which lies at the root of the subject.... For the present we must consider oil as a material in the rocks, the origin of which is still unexplained." I take this occasion to repeat my objection to the above statement, as well as to the similar statement of Mr. C. W. Hayes and William Kennedy in their recent bulletin2 on the same oilfields :—" The origin of petroleum is one of the most obscure problems by which geologists are confronted." I do not hesitate to say that these statements, which claim we know so little to-day of the origin of petroleum, are not warranted in the present state of geological science, and that, on the contrary, geology can to-day most clearly prove the origin of oil to be inorganic and the result of solfataric volcanic emanations. It has been so long assumed that oil or bitumen is due to the decomposition of the organic remains of the sedimentary rocks, that the words organic and bituminous are used synonymously and, accordingly, without attempt at explanation, the origin of oil is in every case ascribed to some bituminous-shale horizon, more or less full of organic matter. Such falla

Jan 1, 1905

By W. B. Plank

THE figures on enrollment in the engineering schools of the United States and Canada indicate that the total number of students in these schools for the current year, 1949-50, is about 10% less than it was a year ago. This year, 226 - 533 undergraduates and graduate students are studying engineering in the United States and Canada as compared with. 249,913 students last year. These figures are taken from advance data in the Journal of Engineering Education for February 1950.

Jan 1, 1950

By P. Chiotti, G. R. Kilp

IN the study of zinc-zirconium1 and zinc-uranium2 systems, vapor-pressure measurements were made in order to establish the equilibrium phase diagrams for a pressure of 1 atm. In each of these systems, only zinc has an appreciable vapor pressure over the temperature range investigated. The zinc pressure was measured over a sufficiently wide temperature and composition range to permit calculation of the standard free energy, enthalpy, and entropy of formation for the compounds ZrZn, ZrZn2, ZrZn3, ZrZn6, ZrZn14 , and U2Zn17. In these calculations the compounds were treated as line compounds. Although the exact composition range was not determined, metallographic and thermal data indicate that the solubility range for these compounds is small. It is to be noted that the compound initially reported to correspond to the formula UZn9, 2 has been shown by the crystal structure work of Makarov and vinogradov3 to correspond to the formula U2Zn17,. The crystal structure is similar to that for the compounds Th2M17, investigated by Florio,4 et al; here M represents iron, cobalt, or nickel. Therefore, thermodynamic calculations are based on the formpla U2Zn17 EXPERIMENTAL The dew-point method employed to measure the vapor pressure of zinc over uranium-zinc alloys has been described previously.2 The same procedure and apparatus were used in measuring the zinc pressure over zinc-zirconium alloys. In the case of alloys in the two-phase region consisting of a zirconium and the compound ZrZn, the Knudsen effusion method was employed to obtain a few values in the temperature range 600" to 560°C. In most cases, tantalum crucibles were used to contain the zirconium alloys. THERMODYNAMIC PROPERTIES OFU2Zn17 A least-squares treatment of the vapor-pressure data obtained for 35 and 65 wt pct U alloys in the temperature range 650° to 940°C gave lOg10PAtm = 7,713/T + 6.33 Here, as in following equations, T represents degrees kelvin and P represents the zinc vapor pressure in atmospheres. The probable errors for the two constants were calculated to be 60.68 and 0.0563, respectively. This relation represents the equilibrium dissociation pressure for the reaction U2Zn17 (s) - 2U(s) + 17Zn(v) The solubility of zinc in solid uranium is negligible and the only additional information required to calculate the free energy of formation of U2Zn17 is the free energy of vaporization of pure zinc. K. K. Kelley5 gives the relations, AF°= 30,902 + 6.03Tlog T + 0.275 X 10-3T2 - 45.03T

Jan 1, 1961

By Harold S. Davis

SURROUNDING the nuclear core of an atomic energy plant there are usually one or more thick walls of concrete, as required to protect instruments and personnel from the harmful effects of nuclear radiations. Sometimes these massive walls are of ordinary concrete weighing about 150 pcf. To reduce wall thicknesses, concrete weighing 200 to 350 pcf may be used. Such high densities are obtained by using natural aggregate processed from heavy ore, or by using steel slugs or iron shot in concrete. Mix data for a number of high-density concretes are summarized in Table I.1 High density at low cost is of prime importance in shields designed to absorb gamma rays. On the other hand, biological shields located near the reactor core must attenuate neutrons as well as gamma rays. In general, a biological shield should contain: 1) heavy elements to slow down high energy neutrons and to absorb gamma rays, 2) either light elements or hydrogenous materials to moderate neutrons of intermediate energy, and 3) materials to absorb neutrons once they have been slowed down to thermal energies. Some shield materials, iron and water for example, are effective in one or more of the above ways. On the other hand, some otherwise excellent shield materials have certain undesirable radiation properties that limit the ways or number of places they can be used. For example, when iron absorbs neutrons it emits secondary gamma rays of high energy. On the other hand, boron absorbs neutrons avidly without producing high energy gamma rays. In spite of its high cost, boron is sometimes used in concrete to minimize production of secondary gamma rays. In some shielding applications it is necessary to avoid materials that become radioactive when subjected to neutron bombardment, continuing to give off high energy gamma rays for long periods after being removed from a neutron field.

Jan 5, 1957

By Robert H. Richards

My first paper, read at the Cobalt Meeting of the Institute,' July, 1907, dealt with the behavior of a small Wilfley table when collceiltrating galena from quartz, the table being fed with natural products, with sized products, and with classified products. Since galena, having a specific gravity of 7.5, is among the heaviest minerals ordinarily concentrated by Wilfley table, it was desirable that a similar set of tests upon a mineral of lighter weight should be made. Chalcopyrite, of a specific gravity of 4, would have been the best mineral for this purpose, on account of its great importance as an economic mineral, but in carrying out the test I was obliged to content myself with a cupriferous pyrite, the specific gravity of which was 4.68 and the content in copper 8.80 per cent. Through the kindness of H. 0. Cummins, this material was obtained from Shasta, Cal., in very pure, clean, homogeneous condition. It was broken by rolls to 2 mm. in size, taking care to make a minimum of slimes. The quartz used to mix with it was pure, white, New England quartz, broken in the same way to the same size. In studying the accompanying tables, it should be borne in mind that the material concentrated was of low copper-content, and in many cases the quantity fed to the machine was 1 kg. or less. As a consequence of the smallness of the quantity treated it was very difficult to adjust the table and get it in condition to do its best work before the feed became exhausted, and for this reason many results were obtained which appear irregular.

Jan 1, 1909

PRESIDENT Michael Lawrence Haider New York City PAST PRESIDENT Willis McGerald Peirce New York City VICE-PRESIDENTS 0. B. J. Fraser, New York City J. B. Morrow, Pittsburgh, Pa. J. L Gillson, Wilmington, Del. ' L F. Reinartz, Middletown, 0. Philip Kraft, New York City R. W. Thomas, Tucson, Ariz

Jan 1, 1952

PAST PRESIDENT WILLIS MCGERALD PEIRCE New York City PRESIDENT-ELECT AND TREASURER ANDREW FLETCHER New York City VICE-PRESIDENTS O B J FRASER, New York City J B MORROW,' Pittsburgh, Pa. J L GILLSON, Wilmington, Del L F REINARTZ, Middletown, O PHILIP KRAFT, New York City W THOMAS,' Tucson, Ariz.

Jan 1, 1952

By Ross W. Smith, Salim Akhtar

INTRODUCTION Flotation of oxide minerals, particularly silicates, with cationic collectors differs substantially from classic flotation of sulfide minerals using sulfhydryl collectors. In the case of cationic flotation of these minerals, in general: 1. There is a greater importance of electrostatic interaction between mineral and collector. 2. Longer-chained collectors are required; as a rule at least 10 carbons must be present in the hydrocarbon chain. 3. Moderate concentration of collector is required. 4. Attachment between collector and mineral appears to be less strong even though the system may exhibit a large contact angle. 5. Required conditioning time before flotation is usually relatively short. 6. There is sensitivity to slimes. 7. The collectors usually possess frothing power. 8. Selectivity of cationic collectors for specific minerals is usually poor. Almost any of the oxide and silicate minerals may be floated using cationic collectors. However, specific response to these collectors varies with mineral type. The following classes and minerals are

Jan 1, 1976

By Hermsdorf, Richard P. E.

AMONG the newer lead smelting and refining plants of the country is that of the United States Metals Refining Co., at Carteret, N. J. Not only is the technical practice here modern and efficient, but exceptional care is taken to assure healthful operating conditions for the employees. One large building houses the entire department, which includes, as its chief units, one reverberatory smelting furnace, one blast furnace, two softening furnaces, one utility reverberatory furnace, two Faber du Faur retorts, five 120-ton kettles, three 60-ton antimouial lead kettles, and one 5-ton kettle for experimental purposes. There is a 10-ton overhead crane in the kettle aisle, which is also used for shipping lead. Other auxiliary equipment is referred to in the outline of operations. A general plan of the plant is shown in Fig. 2, and a general view in Fig. 1. Primary smelting operations are conducted in a 30 by 11-ft. reverberatory furnace with bottom, roof, and upper walls of clay brick, magnesite

Jan 1, 1934

By Robert Mehl

A STUDY of the structures arising from the decomposition of the a solid solutions in the Cu-Zn and the Cu-Al systems is of peculiar interest in the study of the mechanism of precipitation from solid solutions. It is possible in these alloys, by varying the composition within the ß field, to precipitate from the same basic lattice phases having different lattice structures. It has been rather generally assumed heretofore that the type of structure originating from the decomposition of a solid solution-the Widmanstätten structure-is determined by the lattice structure of the parent solid solution alone. In the first paper of this series1 evidence was advanced which threw doubt upon this hypothesis; but definite proof of the correctness or incorrectness of the hypothesis should be forthcoming from a study of these alloys, for if the structures originating, for example, from the precipitation of the a phase from ß and of the -y phase from the ß in the Cu-Zn system should be shown to be crystallographically different, the hypothesis would necessarily be held as definitely disproved. Furthermore, the newer proposal enunciated in the first paper of this series-that the origin of the Widmanstätten structure lies in a cooperation between the lattice of the parent solid solution and that of the precipitate-which at present seems the only alternative hypothesis, would in such an event be given added weight. The work here reported shows that the Widmanstätten structures originating in the precipitation of the a phase from the a and in the precipitation of the -y phase from the ß in the Cu-Zn system are indeed crystallographically different; and incidentally presents some new descriptive information on the Widmanstätten structure from a more general point of view.

Jan 1, 1931

By W. B. Agocs

IN August 1954 a low altitude test geophysical survey was made in the Green Pond area of Morris County, New Jersey, with a Gulf Research and Development Co. Model II total magnetic field variation magnetometer mounted in a Sikorsky S-55 helicopter. The test was made in this area to compare the results of a high precision, very low altitude magnetometer survey with an existing ground magnetic survey in this area having known magnetite concentrations, so that the method could be used in areas of difficult access for the detailing of airborne magnetometer anomalies of interest in place of ground surveys. The load capacity of the Sikorsky S-55 permitted installation of a recording scintillation counter so that a radioactivity survey would be made simultaneously with the magnetometer survey. The area surveyed is located at approximately 41°00'N and 74o28'W, just south and east of the town of Green Pond, N. J. The outstanding topographic feature of the region is Copperas Mountain, a well defined ridge, maximum elevation 1222 ft, which runs the entire length of the survey. The lowest point in the survey, 810 ft, is in the extreme eastern corner. Topography of the area is shown in Fig. 1. The three major rock units outcropping in the area are all metamorphic: the Pochuck gneiss, which has been divided into two metamorphic facies; the Byram gneiss; and the Green Pond conglomerate. The relative ages of the Pochuck and Byram formations, both pre-Cambrian, are in doubt, but it is believed that the Pochuck is the older of the two.' The Green Pond conglomerate is Silurian.' Distribution of the outcrops and mine locations is shown in Fig. 1. Two facies of the Pochuck gneiss can be distinguished locally—the Copperas Mountain and Kitchell members. The Copperas Mountain member is a hornblende gneiss, and all the mines and prospects in the area are in this unit. The Kitchell is a quartz-plagioclase feldspar gneiss. The Byram gneiss is a relatively nonresistant valley formation which is high in the potash feldspar. The Green Pond conglomerate is a well indurated quartzite-conglomerate which forms the Copperas Mountain and the Green Pond Mountain's ridge to the north. It overlies the gneisses with a strong angular discordance that may be a fault. The geologic structure of the Green Pond area is relatively uncomplicated. The foliation planes of the gneisses dip steeply to the southeast, and the Green Pond conglomerate dips steeply to the northwest. Additional faulting in the area is indicated at the contact between the Kitchell member of the Pochuck and the Byram along the base of the topographic spur extending to the southeast from Copperas Mountain. The magnetite mines of Pardee, Winter, Davenport, Green Pond, Copperas, and the Bancroft shaft are described by Bayleyl and Stampe2.' The ore is in the Copperas Mountain member of the Pochuck gneiss. The magnetite veins are 10 to 50 ft wide and up to 300 ft long, dipping to the southeast at angles ranging from 40" to 75". The locations of these mines are shown in Fig. 1. Dip Needle Survey: The dip needle survey shown in Fig. 2 was taken from a U. S. Bureau of Mines Report of Investigations." The figure numbers below the local, individual map area outlines refer to the figures in the aforementioned reports which were not contoured. The area of the dip needle survey was confined almost exclusively to the outcrops of the Pochuck gneiss. The separation between survey profiles was 100 ft and the distance between stations on the profiles was 25 ft in highly anomalous zones to 100 ft in magnetically flat areas. A total of 16 1/2 miles of traverse was surveyed over an area of approximately 1/2 sq mile with 2050 stations. The magnitude of the magnetic anomalies is difficult to determine due to the lack of information concerning the type of dip needle used and the procedure followed in making the dip needle survey. This latter would include the method of "zeroing" the dip needle and the procedure of reading at the stations, whether on the swing or statically. Calibrations made of the Gurley dip needle, Lake Superior type, show a static sensitivity of 385 gamma per degree in the range from —25" to +35o, corresponding to a variation in the total field of —9600 gamma to +13500 gamma in a total field of 57000 gamma, inclination 72". The sensitivity increases to 16 gamma per degree from a deflection of 60" to 76", and from 76" to 172" the sensitivity decreases continuously to a low of 260 gamma per degree. From the above it may be seen that it is difficult to assign an arbitrary sensitivity for the dip needle used on this survey. However, an estimated value of 100 gamma per degree may be assigned. On this basis, the majority of the magnetic anomalies, whose deviation is +20°, would be 2000 gamma. Locally, west and northwest of the Pardee mine the magnetic anomaly is +50°, or 5000 gamma; in the Green Pond mine area deviations of +75" are observed that would correspond to anomalies of 7500 gamma. The areal extent and width of the dip needle magnetic anomalies is comparable to profile and station spacing. Hence it is concluded that part of the detail may be due to control, and the probable cause of the magnetic anomalies is at or near surface exposures of magnetite concentrations in the form of veinlets and disseminations whose locations correspond to the local magnetic anomalies. On the basis of the magnetics, none of the magnetite concentra-

Jan 1, 1956

By J. M. Oblak, R. F. Hehemann, R. H. Goodenow

STUDIES of surface relief and growth kinetics have lead to the concept that widmanstatten ferrite along with upper and lower bainite constitute a continuous series of decomposition products.1-4 Current models4 propose that these products form as plates with a coherent or semicoherent leading edge which propagates at a rate controlled by diffusion of carbon into the surrounding austenite. There are, however, important crystallographic and morphological differences between these products—particularly between upper and lower bainite. For example, upper bainite appears to exhibit a (11lIy orientation habit, whereas lower bainite develops with a more irrational habit near {2251y.5-7 Many of the morphological features of these decomposition products are not yet well-documented. Recent studiess have demonstrated that low-carbon martensites form as sheets of closely spaced needles on {lllly planes while higher-carbon martensites form as plates with {225}? or other orientation habits. The similarity in the crystallography of these two modifications of martensite with upper and lower bainite is striking. Therefore, a study of the morphology of bainite in a series of hypoeutec-toid alloy steels has been initiated to explore these relationships further. The question of immediate interest is whether upper and lower bainite form as plates or needles. A two-surface (approximately perpendicular) metallographic method was employed to study the morphology of bainite in a variety of low and medium alloy steels. Compositions of these steels have been reported elewhere. The behavior of 4340 and 4370 was typical and will be described here. Austenitizing treatments involved 20 min at 2350°F for 4340 and at 2000°F for 4370. Isothermal transformation was conducted in molten-salt baths. Upper bainite was produced at 925°F in the 4340 steel and lower bainite at 575°F in 4370 with transformation times adjusted to produce 10 to 15 pct of the decomposition product. Many of the morphological features of upper bainite have been catalogued in the recent literature.'' The two principal variants observed in the present investigation are illustrated in Fig. l(a). One form appears as long, thin plates or needles and the other as small, frequently irregularly shaped particles. Both variants may occur as isolated forms but more frequently appear in groups as demonstrated in Fig. l(a). Two-surface analysis reveals that these two variants constitute different sections through a single morphological form. To demonstrate this, a number of sections perpendicular to the plane of Fig. l(a) were prepared at various positions along the length of the elongated particles. A section taken at position 1 in Fig. l(a) is presented in Fig. l(b). Here, the dark line represents the edge of the sample and the left-hand portion of this photomicrograph is that from the surface perpendicular to the original plane of polish. Since it was necessary to repolish the original surface after each sectioning, the shape of the bainite particles on this surface, right hand side of Fig. l(b), changes with each sectioning. The disappearance of plate A, Fig. l(a), in Fig. l(b) emphasizes the small cross section of these structures. The group of particles in the lower left-hand

Jan 1, 1964

By ARTHUR S. DWIGH

Discussion of the paper of W. W. NORTON, presented at the Salt Lake meeting, August, 1914, and printed in Bulletin No. 92, August., 1914, pp. 1993 to 1999. ARTHUR S. DWIGHT, New York, N. Y.-Mr. Norton's chief argument is directed against the idea that the D. & L. sinter is any better material for the blast furnace than the H. & H. product. He supports this by citing two experimental furnace runs. Reducibility.-To discuss a furnace record like that quoted by Mr. Norton for the five days' run in August, 1912, is manifestly difficult for an outsider, but a possible explanation for the poor reduction on Furnace No. 5, smelting D. & L. sinter, may lie in the fact that both sets of furnaces carried the same fuel charges. Other things being equal, if 11 ½ per cent. coke was right for the furnaces smelting H. & H. product, it Was too much for the furnace smelting D. & L. product, as I shall endeavor to show later, and incipient overfire, accompanied by higher leads in slag and matte, was induced. It may sound like a paradox to say that excessive fuel sometimes produces poor reduction, but it is a sad fact. In certain plants where practically the entire charge to the blast furnaces receives a preliminary treatment by being sintered on the D. & L. machines the peculiarities of this problem have had to be very carefully studied, for serious metallurgical difficulties presented themselves when the change was first made to D. & L. sinter in large quantities. Some of these plants had blast pots before they had D. & L. machines, and many opportunities were afforded for comparative study of this very point. There is reason to believe that, clue to the long period of blowing and the higher temperatures developed in the pots from greater mass action, the iron in the H. & H. product is present chiefly as Fe203, perhaps in the form of ferrites, while in the D. & L. product the iron is present as FeO. The fuel charge in the blast furnace must be so proportioned as to exactly meet the chemical and thermic requirements of reduction and melting. If ally of these functions have been performed before the material enters the furnace, a corresponding allowance should be made or the fuel balance will be disturbed and bad work will result. One of the functions of the coke is to reduce enough metallic Fe for the matte requirements, leaving the remainder of the iron as FeO to go into the slag. In smelting almost any other material than D. & L. sinter the iron must-be reduced from the higher oxides, Fe203 or Fe304, to the protoxide, FeO, before a true comparative basis is reached. Experience has shown that with about one-half D. & L. sinter on the charge the coke should-be cut about 10 per cent. This theoretical benefit is borne out by the practical blast-furnace results on a large scale in numerous plants. In fact, wherever this very important factor is ignored the evil symptoms of excessive fuel will be indicated,

Jan 11, 1914

By M. Lonoff

Byproducts are more important to the copper mining companies than to the copper market. Copper ores frequently contain gold, silver, molybdenum, lead, zinc, and cobalt. With the increase in the prices of these metals copper mining has become more profitable. If byproduct prices remain high, additional firms will be attracted to the copper industry; the increased supply of copper will reduce the long-run copper price. However, this is unlikely to happen because the markets for the copper byproducts, especially molybdenum and cobalt, are small. Increased recovery from copper and other sources will depress the prices of these byproducts before the copper price is significantly affected. Should byproduct prices remain high, the copper market will both settle at a lower long-run price and be more unstable in the short run. Since changes in the copper price do not affect the entire earnings of a multi-metal mine, the copper price must fall further before such mines reduce output in the short run. Higher byproduct revenues will make copper supply less responsive to copper prices; shifts in copper demand will result in greater copper price fluctuations in the short run than they did before.

Jan 1, 1984

ALABAMA Altoona.-Cain, J. America.-Foreman, J. T. Anniston.-Cowie, L. K. Foster, R. N. Ashland.-Sturdevant, J C Bessemer.-Ball, E. M. McKenzie, W. C., Jr Birmingham.-Abbott, C. E. Aldrich, T. H. Aldrich, T. H, Jr. Ashton, J J. Ball, T. L. Blair, C. S. Brown, T S. Bush, M. W.

Jan 1, 1923

By Stanley Rajnak, John E. Dorn

The saddle-point activation energy for the nu-cleation of a pair of kinks is estimated as a function of the applied stress, the lattice constants, and the height and shape of the Peierls' hill by employing the line-energy model of a dislocation. The kinetics of disloration motion by the Peierls' mechanism are discussed and the microscopic dislocation velocities and macroscopic strain rates are formulated by the Arrkenius type of approach in terms of the activation energy for the formation of pairs of PEIERLS was the first to illustrate that a straight-dislocation line has its lowest energy when it lies in a potential valley parallel to lines of closest packing kinks. The log of the dislocation velocity is found to be approximately proportional to the log of the local applied stress. It is also shown that the low-temperature mechmical properties of several bcc metals might be explained in terms of the Peierls mechanism, good agreement being obtained between theory and experiment for the flow stress us ternperature, activation energy vs stress, and activation volume us stress curves for these metals. of atoms on the slip plane. When such a straight dislocation is moved rigidly from one valley toward the next, the atoms in the vicinity of the core of the dislocation change their positions and bond angles, causing the energy of the dislocation to increase. Midway between two adjacent valleys, the disloca-tion energy reaches a maximum value and any additional small displacement will cause the dislocation to fall down the hill into the next valley. The maximum shear stress necessary to promote such

Jan 1, 1964

By L. K. Eigenbrod, F. Notaro

Enactment of Public Law 91-173 (Federal Coal Mine Health and Safety Act of 1969) has placed new responsibilities on the mining industry. The new law, aimed at eventually solving the problem of pneumoconiosis, sets new respirable dust standards at 2 mg per cu m. Techniques employed to date have been shown to lack total effectiveness in meeting the prescribed standards. Since it is possible that even the new standards will eventually have to be lowered to effectively attack the medical problem, the need for new and more reliable methods of assuring clean respirable air will intensity. This paper presents, in a preliminary manner, both the present technical capability and growth potential of cryogenic technology for supplying miners with clean breathing air. Work with two sizes of prototype supplied-air (cryogenic-liquid) respiratiors in Union Carbide's Fawn Coal mine, will be described. Other potentially fabricable systems will be discussed and a preliminary assessment made of the potential cost of introducing cryogenic air breathing systems in coal mine service.

Jan 1, 1972

By E. H. Bunce, E. C. Handwerk

The inherent difficulties of zinc smelting arise from the fact that metallic zinc is volatilized at the reducing temperature of zinc oxide and thus is liberated in the form of a vapor. This vapor must be subsequently condensed to obtain metallic zinc, first in molten and eventually in solid form. Zinc vapor is sensitive to oxidation not only by air but by combustion gases containing carbon dioxide. It is, therefore, necessary to carry out both the reduction and the condensation operations in a closed system consisting of an externally heated muffle with attached condenser from which extcrnal oxidizing agencies are excluded. However, the reoxidation of zinc vapor cannot be entirely prevented by excluding external sources of oxidation. Internal sources of oxidation are necessarily present when oxidic zinc ores are reduced by a carbonaceous reducing agent. The reduction reactions themselves involve, first, the production of carbon monoxide in an amount at least equal in volume to the zinc vapor produced in the reaction, and, second, the formation of carbon dioxide. Not all of the carbon dioxide is reduced again to carbon monoxide by the excess carbon in the time available, and the slightly oxidizing condition, which results, seriously affects the efficiency of the condensation of the zinc vapor to the metallic state. In the past the difficulties arising from these causes have limited practical zinc smelting on an industrial scale to the use of small retorts equipped with small condensers. The retorts had to be small, because a closed refractory container capable of excluding oxidizing gases from the heating chamber surrounding the retort could not be built in large dimensions. The size was also limited because ordinary refractories when thin enough to conduct heat readily are not capable of sustaining a heavy load of charge at high temperature. Moreover, a loose charge of zinc ore and carbonaceous reducing material such as fine anthracite coal or coke breeze is a poor conductor of heat, thus limiting the cross section of the retort. The operation of these small retorts requires arduous

Jan 1, 1937

By B. C. Allen, R. I. Jaffee, D. J. Maykuth

Wrought unalloyed iodide chromium, containing 39 to 95 ppm total interstitials, has a tensile transition temperature of —15°C. Re crystallizing at 1100°C causes the transition to rise to 90° to 390°C, depending on the purity, grain size, and cooling rate after annealing. At about the 100 ppm level, individual additions of carbon or nitrogen raise the transition of both wrought and recrystallized chromium by as much as 210°C, while oxygen has a lesser effect, and sulfur essentially no effect. High transitzon temperatures are exhibited by recrystallized and quenched chromium, and appear to be associated with the amount and distribution of inter-stitials. The latter cm be either in solid solution or in the form of precipitates within the grains or at the grain boundaries. Quench hardening in chromium is primarily caused by nitrogen. The hardness, re crystallization, and grain growth behavior of chromium with and without impurity additions were also investigated. BECAUSE of low density and good oxidation resistance, chromium-base alloys are potentially useful for elevated-temperature applications. The main deterrent to the use of chromium in structural applications is its lack of low-temperature ductility, especially in the recrystallized condition. Accumulated evidence has shown that the ductility of chromium is sensitive to purity. The objective of the current study was to determine the effect of common nonmetallic impurities on the tensile properties of high purity chromium. The separate effects of carbon, oxygen, nitrogen, and sulfur additions on the ductile-to-brittle transition were evaluated for wrought and recrystallized material after various cooling rates. EXPERIMENTAL WORK Unalloyed iodide chromium and seven impurity alloys containing individual carbon, oxygen, nitrogen, or sulfur additions were prepared in rod form. Nominal additions were 100 ppm C, N, and S, and 100 to 500 ppm O. The additions were about a factor of ten greater than the residual amounts in the unalloyed material. The seven alloys and two unalloyed compositions were consolidated into four-pound ingots by conventional consumable arc melting of pressed and welded electrodes under 0.5 atm of helium. Impurity additions were made to the electrode in the form of crushed master alloys. The impurity alloys were double melted to improve homogeneity. The ingots were broken down by extrusion at 1200°C in evacuated steel cans at a reduction ratio of 18 :1, using a molten borosilicate glass lubricant and a ram speed of 80 in. per min. The cans were removed by acid pickling, and the chromium core ground free of surface undulations. Cut lengths were sheathed in mild steel and swaged at 900°C until the core was about 1/4 in. in diam. Two additional 15-lb ingots of unalloyed chromium (ICr-3, ICr-4) were prepared by arc melting and broken down by 26:1 extrusion at 1250°C without a steel can. The billet was lubricated and protected from contamination by a coating of molten glass. The resulting extrusion was then sheath swaged as described previously. Representative chemical analyses of each of the materials, after removal of a 10-mil surface layer

Jan 1, 1963

The following is an incomplete list of members and guests who called at Institute headquarters during the period Sept. 10, 1919, to Oct. 10, 1919. L. D. Anderson, Salt Lake City, Utah. P. S. Matthews, Newark, N. J. Ray J. Barber, New York City. A. Poole Maynard, Atlanta, Georgia. L. A. Barton, Major U. S. Engineers. L. J. Mayreis, Jamshedpur, India. J. A. Battle, Chicago, 111. Benj. L. Miller, Bethlehem, Pa. R. W. Bissell, New York City. Geo. D. Morgan, Bartlesville, Okla. Gilman E. Brown, Shanghai, China. A. C. Munroe, El Paso, Texas. Stanley Brown, Chuquicamata, Chile, Paul I. Norton, Jr., Columbus, Ohio. S. A. Walter G. Perkins, Stanford University, Norman Carmichael, Clifton, Arizona. Cal. Richard H. Catlett, Newark, N. J. Fred S. Porter, Seattle, Wash. Roderic Crandall Charles E. Prior, Cherry Creek, Nevada John J. Croston, Atlanta, Georgia. G. M. Richards I. N. Dally, Seattle, Wash. Gilbert Rigg, Melbourne, Australia. A. Faison Dixon, New York City. Pierre H. Sauvajol, Paris, France. Walter Dobbins, Springfield, Ill. Carl Scholz, Chicago, Ill. Foss E. Douglass, Rancagua, Chile. Ellsworth H. Shriver, Marysville, Ohio. H. S. Emlaw, Grand Haven, Mich. Harvey B. Small, Magangue, Colombia. R. S. Everet, Barre, Mass. Henry B. Smith, New Britain, Coma. H. W. Gipp, Melbourne, Australia. J. T. Smoody, Cornwall, Pa. F. A. Glass, Brainerd, Minn. S.. J. Speak, London, England. C. D. Grier, New York City. D. R. Thomas, New York City. James L. Head, Rancagua, Chile. Kirby Thomas, New York City. Geo. B. Holderer, New York City. R. M. F. Townsend, Washington, D. C. W. Spencer Hutchinson, Boston, Mass. Carl J. Trauerman, Helena, Mont. Henry Jequier, Paris, France. A. C. Veatch, London, Eng. L. W. Kemp, Chuquicamata, Chile. Myron R. Walker, Pittsburg, Pa. Herbert S. Kohlberg, El Paso, Texas. Curtis C. Webb, New York City. H. M. LaFollette, La Follette, Tenn. James Wilding, San Francisco, Cal. Richard Lamb, New York City. S. H. Zimmerman, New York City.

Jan 11, 1919