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By R. C. Nelson, T. L. Weaver, A. I. Michals

This paper describes the design and performance of an apparatus for making continuous nondestructive resistance measurements throughout a spool of fine wire. Highly reproducible results on clean and graphite coated tungsten and rnolybdenum wires from 1 to 9.5 mil are presented. A linear relation between resistance and wire weight (per standard length) was obtained on clean wires, but only on those coated wires with very uniform coatings. Results indicating a correlation between tensile strength, hardness, and resistivity are reported. THE increasing demand for greater uniformity in fine tungsten and molybdenum wires destined for use as mandrels, grids, and coils in radio tubes and as filaments in light bulbs has rendered inadequate the standard (sampling) approach to the control of wire diameter and other physical properties. This ap-

Jan 1, 1961

The First Conference of the Powder Metallurgy Committee convened in the East Foyer of the Hotel Waldorf-Astoria, New York City, at 9:45 a.m., on Feb. 21, 1944, Mr. John Wulff, General Chairman, presiding. THE CHAIRMAN.-In behalf of the American Institute of Mining and Metallurgical Engineers I welcome all members and guests to this conference on Powder Metallurgy. We hope that this meeting will give expert and novice in the field a chance for discussion. Unfortunately, the subject has been overemphasized by some, and, of late, severely criticized by others. We have here today powder producers, fabricators, and engineers of different viewpoints, who can make the meeting a success. Such success depends not only on the caliber of the papers presented but more so on the discussion. To give you time for a free exchange of views, the papers have been shortened purposely. With the hope that you will all benefit by this conference, I shall turn the meeting over to the Chairmen of the morning session, Mr. Roland P. Koehring, of Moraine Products Division of General Motors, and Dr. R. K. Waring, of the New Jersey Zinc Company. SESSION ON DESIGN FACTORS IN POWDER METALLURGY R. P. Koehring and R. K. Waring presiding The opening paper of the session was presented by Mr. Fred P. Peters, as follows:

Jan 1, 1945

By W. B. Phillips

The earliest mention of the sulphur deposits in what is now Culberson County, Texas, seems to be contained in " Explorations and Surveys for a Railroad Route from the Mississippi River to the Pacific Ocean, United States War Department, 1853-54." Captain John Pope (he was not commissioned Captain until 1856) had charge of one of the divisions of the Survey. In his report on the geology of the route, William P. Blake noted the analysis of a greenish earthy powder from the bed of Delaware Creek, at the springs, which contained 18.28 per cent. of free sulphur. The report states: "From the chemical examination of the waters of the spring, by Dr. Booth, it appears that chloride of sodium is the principal solid ingredient, but considerable quantities of sulphide of sodium are present. ***** The waters from the springs examined by Dr. Booth were alkaline, but it is possible that some of the springs are acid; and in this case the precipitation of sulphur would ensue on the mixture of the acid waters with those charged with alkaline sulphurets and the origin of the deposits of sulphur would be thus explained." This is the first reference to the existence of sulphur in that region, the first mention of the character of the water found there and the first suggestion as to the origin of the deposits. The possibility of the existence of acid waters was confirmed by E. M. Skeats, nearly 50 years later.' In this publication, Skeats says that the water from the sulphur deposits in Section 11, Block 114, Township 6, contains 79.08 grains of free sillphuric acid per gallon. This locality is about 13 miles (21 km.) south . of Delaware Creek and about 35 miles (56 km.) east of the Delaware Springs. The next published reference to the existence of sulphur in Trans-Pecos. Texas is in the Pirst Annual Report of the Geological Survey of Texas, 1889, page 226, where W. H. von Streeruwitz mentions that sulphur is found in that region, but gives no further information. In the

Jan 1, 1918

By J. O. Glanville, L. H. Haley

Ice frozen from a dilute chemical solution is mechanically weaker than ice frozen from pure water. This phenomenon is the basis of a practical method for reducing the strength of a mass of frozen coal. If a chemical additive is applied to moist coal prior to its shipment during freezing weather, the resulting frozen coal can be more easily broken than in the absence of the chemical additive. This greatly expedites the unloading and handling of coal during winter. There has been considerable research into the nature and mechanical strength of ice frozen from various solutions. In this paper, literature relating to this process as well as literature relating to the chemical treatment of coal and mineral particulates is reviewed. Some important articles are discussed and speculations made about the nature of the ice-weakening process. A laboratory evaluation of the effects of chemical additives on the mechanical strength of ice and frozen coal has been made. An apparatus designed for this purpose is described, and some results obtained with it are discussed.

Jan 1, 1983

[Appalachian Petroleum Section: James M. Kimbrough, chairman; John H. Adair, first vice-chairman; Walter L. Diddle, second vice-chairman; Byron M. Finch, secretary-treasurer. Balcones Section: Robert V. West, chairman; Frank W. Jessen, first vice-chairman; Zane V. Morgan, second vice-chairman; Brantley G. Myers, secretary-treasurer. Meets 4th Wed., Petroleum Club (San Antonio) or Terrace Dining Room (Austin) Billings Petroleum Section: Charles B. Evans, chairman; L. M. Lyon, first vice-chairman; Gordon E. Lansford, second vice-chairman; Fred. A. Haddenhorst, secretary-treasurer. Meets 3rd Tues., Billings Petroleum Club. California Coastal Section: Robert L. Richardson, chairman; David K. Hayward, first vice-chairman; W. Jackson Bransford, secretary; William N. Harwell, treasurer. Meets 3rd Thurs., Pierport Inn, Ventura. Caracas Petroleum Section: Edwin A. Moo re, chairman;. Jose Cirigliano, vice-chairman; Frank B. Davis, secretary; Robert N. Powers, treasurer. Meets 2nd Tues., Caracas Theater Club.]

Jan 1, 1961

By G. R. Smithson, John E. Hanway

This paper, the first of two papers covering the development of a metallurgical process for the treatment of a complex ore, describes the bench-scale experimental Program undertaken as a basis for initial process design. The results of using various potentially applicable process steps are detailed and the basis for selecting certain of these steps for Pilot-plant development is outlined. A process consisting of the steps of sulfate roasting, leaching, copper recovery, solution purification, zinc electrolysis, and brine leaching for lead recovery was recommended for further study. THIS paper describes the bench-scale development of a sulfate roasting process designed to recover copper, lead, and zinc from a complex ore. The extrapolation of the bench-scale results to pilot-plant design and the results of pilot-plant operation will be described by Lund, et al.' in a subsequent paper. Several years ago, the research divisions of the St. Joseph Lead Co. became responsible for the development of a metallurgical procedure to treat a complex sulfide ore containing copper, zinc, and lead sulfides. The primary objective was to devise a procedure which would permit economic recovery of the nonferrous values. As could logically be expected, the study of conventional flotation procedures was undertaken; in addition, however, because the physical nature of the mineral association in the complex ore indicated that physical methods of ore beneficiation might not prove to be entirely satisfactory, a program also was established to investigate alternative methods of direct metallurgical treatment for recovery of the metal values. Exploratory test work by the St. Joseph Lead staff led to the conclusion that a sulfate roasting technique represented the most attractive approach for a direct metallurgical process. Sulfate roasting would provide for the selective conversion of the nonferrous values to forms soluble in conventiona1.1 leaching agents and would permit their efficient separation from the insoluble iron and other gangue materials. It should allow efficient utilization of the thermal energy available from oxidation of the sulfide raw material, and might provide an opportunity for recovering byproducts such as iron and sulfur. The decision to evaluate a selective sulfation procedure as a basic processing step also was influenced by the excellent results obtained by the St. Joseph Lead Co. in using this procedure for the recovery of cadmium from zinc sulfide concentrates. The choice of selective sulfation as a major processing step served as a basis for an extended experimental investigation of the process with bench- and pilot-scale equipment to prove its feasibility. St Joseph Lead Co., aware that Battelle Memorial 1nstitute had participated in the development of several fluidized-bed sulfate roasting procedures, asked Battelle to undertake the bench-scale development of a suitable sulfation process. This paper describes the procedure used and the results obtained at Battelle in the treatment of the complex sulfide ore. EXPERIMENTAL WORK Nature of the Raw Material. The sulfide ore deposits of interest are essentially a massive sulfide, with the indivudual ore minerals being extremely fine grained and intimately intergrown with each other and with the associated gangue. The zinc in the ore is present mainly as sphalerite (ZnS), the lead as galena (PbS), and the iron either as pyrite (Fes2) or as pyrrhotite (FeS). Table I shows the chemical analysis of various individual samples of the ore. These analyses illustrate the variability of the ore body and impose a rather severe requirement on any type of metallurgical process—that of being able to tolerate probable wide variations in the assay of the head ore. The tentative flowsheet designed to serve as a guide for the initial experimental investigation of

Jan 1, 1962

EXECUTIVE COMMITTEE OF THE BOARD OF DIRECTORS W E WRATHER, Chairman A B KINZEL -EARLE E SCHUMACHER DONALD H MCLAUGHLIN - JOHN R SUMAN FINANCE COMMITTEE OF THE BOARD OF DIRECTORS ERLE V DAVELER, Chairman PHILIP KRAFT - CLYDE E WEED

Jan 1, 1952

A tentative plan for the Colorado Meeting has been formulated as follows: One day will be spent at Denver, one day at Colorado Springs, one day at Cripple Creek, a trip by automobile to the top of Pike's Peak, one day at Pueblo, one day at Leadville. All the principal mines and mills of the districts mentioned will be visited, including the gold mines in Cripple Creek, the lead, zinc, and steel works. of Pueblo, the production of ferro-molybdenum by electric furnace at Leadville, etc. Special arrangements are being made for the social entertainment of ladies at all points; one evening at Colorado Springs will be devoted to a reception and dance, and the usual dinner will he given on another evening. The following papers have already been accepted for the Colorado Meeting, and some have already been published: Fireproofing Mine Shafts by the Anaconda Copper Mining Co. By E. M. Norris. (March Bulletin.) Air Blasts in the Kolar Gold Field, India. By E. S. Moore. (March Bulletin.) The Use of Coal in Pulverized Form. By H. R. Collins. (April Bulletin.) Coal Mining in Washington. By F. A. Hill. (April Bulletin.) Carbocoal. By C. T. Malcolmson. (May Bulletin.) Gaging and Storage of Oil in the Mid-continent Field. By O. U. Bradley. (March Bulletin.) An Interpretation of the So-called Paraffin Dirt of the Gulf Coast Oil Fields. By A. D. Brokaw. (April Bulletin.) The Theory of Volcanic Origin of Salt Domes. By. E. DeGolyer. (May Bulletin.)

Jan 5, 1918

By N. A. Elmslie

This subject covers much ground, therefore it must be treated in a general way rather than in detail in this paper. Personnel To approach the measure of a mine, it is, of course, essential that the personnel be measured, and this measuring must be done in a circumspect manner and conclusions must be reached slowly. There may be one unit in the personnel of an organization that may be out of step with the remainder of the organization, not always because of lack of ability, but because of misplacement or lack of proper measurement of his capabilities. Too much time can scarcely be spent in the study or measure of the personnel ; in fact, a manager or a superintendent of a mine never completes his work along this line. Mine or Plant Just as no two men are alike, so no two mines or plants are alike; and yet there are many similarities. Find out what the similarities are, and this will help to make clear the dissimilarities. Try to visualize details of the difficulties, not because you will have to deal with them yourself, but to consider them in later studies of general problems. To outline all the steps to be taken in familiarizing oneself with a plant or operation would be impossible, but the following points may be of interest in any investigation. The study of a mine is generally made backwards-—that is to say, one sees the finished product first-—-but this is immaterial, because each step must be considered separately in any event. As a rule, there are certain heads under which the different features of mining can be placed, as follows: Ventilation.—Ventilation is usually the most important item in power cost and safety, especially in gassy mines. Quantity of air, water gage and power consumption, and finally analysis of the return air in full return and separate splits should be considered. Type of fan and type of power unit should enter into this study because it is important to view expenditures which are going on 24 hr. a day and 36.5 days in the

Jan 1, 1931

By A. H. Daane, J. J. Hanak, F. H. Spedding

IN the study of the rare earths at the authors' laboratory, methods have been devised for preparing pure rare earths and many of their properties'- have been determined. Very little information is found in the literature on the properties of europium metal, which is the scarcest of the naturally occurring rare earths. Since we have recently prepared europium in appreciable quantities, we are in a position to describe the method of preparation and some of the properties of this metal. Metallic europium was first prepared by Klemm and Bommera who heated a mixture of potassium and EuC1, in vacuo, and obtained a mixture of europium metal and KC1. Trombe4 electrolyzed a molten salt bath containing NaC1, KC1 and EuC1, and collected the europium in a molten cadmium electrode as a cadmium alloy. The cadmium was subsequently removed by distillation but the properties of the residue indicate that pure europium was not obtained. McCoy attempted to prepare europium by distilling mercury from europium amalgam, but the stability of the Eu-Hg intermetallic compounds prevented a complete separation of the two elements. The preparation of very pure europium was suggested by previous work in this laboratory1,4 in which ytterbium and samarium were prepared by heating the respective sesquioxides with lanthanum metal turnings to 1450°C in vacuo and distilling ytterbium and samarium from the mixtures. Subsequently, small test experiments showed that europium also could be prepared by this method. A more detailed version of this method was used in the work described in this paper. Klemm and Bommer3 found by X-ray analysis that the metal had a body-centered cubic (bcc) structure with a lattice constant a, = 4.582 ± 0.00A (converted from kX units), with a bulk density of 5.30 g per cu cm. They found europium to be weakly ferromagnetic. Spedding, et al,7 found a,, to be 4.606 ± 0.001A. Barrett' showed that the bcc structure persists throughout the temperature range 5 to 3000K with a, at 5, 78, and 300°K being 4.551 ± 0.003, 4.551 ± 0.004 and 4.577 ± 0.001A, respectively. Trombe1 described europium as being iron gray, malleable, about as hard as neodymium and not attacked by cold water. He estimated the melting point to be between 1100 and 1200°C. Previous work in this laboratory indicated that the pure metal corrodes rapidly in air and reacts with cold

Jan 1, 1959

By A. Gatti, R. L. Fullman

A very fine dispersion of aluminum oxide is produced by internal oxidation of solid-solution alloy of 0.14 pet A1 in Ag. The particle size of the aluminum oxide is approximntely 50 to 100A in radius. The yield strength of the alloy is increased markedly by internal oxidation. A further increase in strength is produced by cold working the internally oxidized alloy. Recrystallization is retarded by the finely dispessed aluminum oxide particles, so that the strength increase resulting from cold work is retained on annealing at temperatures 14 to about 700°C. MANY workers'-3 in the past have studied various aspects of the internal oxidation of aluminum-silver alloys. This paper is an extension of these studies with emphasis placed on the effect of time and temperature of annealing on the strength of these alloys after oxidation and subsequent cold working. Two general conditions are necessary to internally oxidize an alloy. First, oxygen must diffuse through the base material more rapidly than does the addition; otherwise oxidation will take place as a surface layer. Secondly, the affinity of oxygen for the addition must be greater than for the base material. After internal oxidation of certain alloys takes place, a marked increase in hardness accompanied by higher yield stress and improved creep properties is noted, presumably as a result of the highly dispersed oxide within the base material. Meijering and Druyvesteyn1 also noted that the internally oxidized portion of a partly oxidized alloy failed to recrys-tallize under annealing conditions that led to coinplete recrystallization of the unoxidized part. EXPERIMENTAL-METHODS AND PROCEDURES Few alloys can be made to contain a second phase that is extremely stable at high temperatures. Silver plus aluminum in solid solution was chosen for these internal oxidation studies because of the high rate of oxygen diffusion through silver and the very stable nature of aluminum oxide. Two alloys were vacuum cast. The nominal compositions were: Alloy A—1 pct Al, balance Ag; Alloy B—0.1 pct Al, balance Ag. Chemical analysis, which does not distinguish between aluminum and aluminum oxide, showed the conlposition to be: Alloy A—1.6 pct Al, and Alloy B—0.14 pct Al. The ingots were machined for surface cleaning, swaged and drawn to 0.020-in. diam wire. A sample 20 ft long of the 0.020-in. dianl wire of each composition was annealed 24 hr at 800°C in pure dry hydrogen. Each wire was then cut into two equal pieces. Photomicrographs of the 0.14 pct A1 alloy are shown in Fig. 1, the annealed 0.020-in. wire at the left and the oxidized wire to the right. The oxidation treatment for the first set of data was 1000 hr at 800°C in air. After this treatment the 1 pct A1 proved to be brittle. It is assumed that high alunlinum oxide concentration at the grain boundaries was responsible. The 0.14 pct Al wire remained ductile and all further data were derived using this alloy. One-half of this wire, about 5 ft, plus 5 ft of as-homogenized wire, was then drawn cold to 0.005 in. diam. All tensile tests were conducted with an Instron Engineering Corp. tensile-testing machine, Model TT-B. Unless otherwise indicated, the tests were made at room temperature with a strain rate of 0.1 per min. All metallographic samples were etched with an aqueous solution of 2 pct each of CrO3 and H2SO4 . EXPERIMENTAL RESULTS AND DISCUSSION PARTICLE SIZE DETERMINATION A study was made of the particle size of the aluminum oxide produced in the samples of Ag + 0.14 pct Al, oxidized 1000 hr at 800°C. A cross section of the as-oxidized wire was mounted in bakelite, polished, and etched with an aqueous solution of 2 pct each of CrO3 and H2SO4. The specimen was then thoroughly cleaned by stripping successive coatings made by applying 10 pct nitrocellulose in amyl acetate. The final replica of the cross section was made by applying 2 pct nitrocellulose in amyl acetate. The replica was stripped, transferred to a copper screen, shadow cast with chromium at 10 deg and photographs taken using a Phillips Metallix electron microscope at an accelerating potential of 100 kv. A photograph of an etched sample of the as-oxidized material is shown in Fig. 2. We believe the pits in the photograph are places were A12O3 inclusions were sitting in the matrix. By inspection, it appears that the volume fraction ob-

Jan 1, 1960

The Committee on Technical Nomenclature, of which John T. Faig, Professor of Mechanical Engineering at the University of Cincinnati, is Chairman, appointed by the Society for the Promotion of Engineering Education, has recently issued a report advocating uniformity in the use of symbols to designate engineering and mathematical terms: The selection of the symbols was based upon a canvas of a considerable number of engineers, editors of engineering papers, and professors of engineering throughout the United States. The list, as finally accepted by the Committee and recommended for universal adoption, is as follows: Concept Symbol I Concept Symbol Acceleration due to gravity 'g Length L Acceleration, linear a Mass m Area A Modulus of section Z Breadth b Modulus of elasticity, Young's... E Center of rotation 0 Moment of force M Coefficients and constants C, K Moment of inertia, polar J Deflection of beam y Moment of inertia, rectangular.. I Depth : d Quantity of liquid flowing Q Diameter D . Radius r Distance passed over s Radius of gyration k Distance of extreme fiber from Reactions R neutral aids C Revolutions per unit of time.... N Eccentricity of application of load e Stress, unit S Efficiency (hydr., mech., vol.)...er,.em, e9 Time t Force F Torque T Friction, coefficient of f Velocity, angular :. W Head H 'Velocity, linear V Height h Volume V Horsepower : Hp Weight W Hydraulic radius Re Previous lists of symbols have not secured wide acceptance in, this country; some that have been proposed by prominent writers are familiar to very few engineers. The above list is presented in the hope that it will assist in the evolution of a standard list. It is short; it contains no Greek letters; it is mnemonic to a considerable degree, though not by

Jan 1, 1918

By F. W. Jessen, N. Mungan

The plastic flow characteristics of clay water suspensions were first recognized by Binghaml in 1916 and further studied by Ambrose and Loomis' in 1931-1932. Many physical and chemical properties of clay suspensions are deeply influenced by particle size distribution as well as by the exchange cation. Separation of a number of fractions is particularly helpful in making a detailed study of a suspension. A limited amount of work has been conducted on the effects of particle size on specific properties of mud drilling fluids. A knowledge of particle size distribution is essential for a better understanding of fundamental properties of clay suspensions, particularly viscosity and gel strength. The purpose of this investigation was to study the effect of particle size on the viscosity and gel properties of clay suspensions and to determine any changes in mineral composition accompanying variation in size. EXPERIMENTAL PROCEDURE Numerous methods may be used to fractionate a poly-dispersed clay suspension into nearly mono-dispersed systems. Particles larger than 44 micron (325-mesh) may be obtained by wet screening. For sizes from 44 to 1 micron, the fractionation may be accomplished by sedimentation, elutriation plus microscopy,' or turbidimetry.6 When dealing with systems which contain a major portion of particles below l-mi-cron size, slit ultramicroscopy,7 centrifuge methods of Svedberg,5 eams,9 and McBain,l0 and X-ray methods" may be employed. The Sharples super centrifuge has been proved suitable for the economical separation of suspended particles of submicron range.12,13,14 Three-hundred and forty-five gal of 1 per cent by weight Aquagel suspension was mixed in a high-speed 5-gallon mud mixer and the suspension was allowed to stand in 5-gal glass bottles for 30 days to assure full hydration. All particles larger than 44 microns were removed by wet screening. Five fractions in the range of 44 to 1 micron were obtained by sedimentation. The Sharples super centrifuge method described by Hauser and Reed.13 Norton and Speil,14 Ha user and Lynn,15 and Hauser and Schachman,10 as employed to yield five fractions of submicron size. A super centrifuge operation chart prepared by Fancher, Oliphant, and Houssierre12 was used to determine operating conditions for the desired particle ranges. The clay suspension, after removal of all material above 1-micron size, was centrifuged. During rotation of the bowl, the particles were deposited on a thin plastic liner which fit closely inside the bowl. After passing 5 gal of suspension through the centrifuge, the liner was removed and the particles on the liner were scraped off, remixed and recentrifuged. This was repeated five times. Thus, Fractions H, I, K, and L were obtained. The finest fraction, M, remained in an approximately 0.4 per cent suspension. Water was evaporated under reduced pressure from this suspension to yield the finest particles. Results of the fractionation are included in Table 1. In order to achieve proper orientation and humidity conditions for X-ray diffraction analysis, the following procedure was employed. The dilute suspensions were placed on glass slides and allowed to dry at room temperature. This was repeated several times. Previous to measurement each sample first was placed in a water desiccator for half an hour and then allowed to stand for 15 minutes at room temperature. thus yielding an equilibrium condition of about 52 per cent relative humidity. The relative humidity of the room in which the X-ray diffraction was carried out was maintained at approximately 50 per cent so that there was no change in the spacings during the X-ray examination. Samples

By Chester T. Sims, Robert I. Jaffee

The thermoelectric behavior of the Pt—Pt-Re thermocouple and the resistance of rhenium to attack by certain molten metals is discussed. In addition, data are presented on the stress-rupture behavior of drawn wire, the tensile characteristics of rolled sheet, the variation of Young's modulus with temperature, and the effect of specimen size and fabrication method on the work harden ability. Mechanical properties of thoriated rhenium are discussed. This includes data on the effect of thoria in rhenium on tensile properties, ductility, work hardening, and recrystallization. RECENT work by the authors', has described methods of fabrication and some of the physical and mechanical properties of rhenium. Rhenium was established as a high melting, dense, refractory-type metal with favorable mechanical properties. In addition, Todd and co-workers' and others" have studied such properties of rhenium as the work function, specific heat, and the resistance of rhenium to the water cycle. Revelation of these and other properties has led to serious consideration for application as electrical contacts, high temperature thermocouples, and wear resistant materials. chanical properties reported previously,' several additional examinations have been conducted. The stress-rupture behavior and the Young's modulus of rhenium have been investigated at elevated temperatures. Tensile data have been obtained for rolled sheet, and a study of the relative work hardening characteristics of rod, wire, and sheet has been conducted. Variation of Modulus of Elasticity With Temperature—The Young's modulus of a % in. diam annealed rhenium rod was determined from room temperature to 880"C (1620OF). The rod, approximately 6 in. in length, was activated in a transverse vibration apparatus suspended in a furnace. The resonance frequencies of the rod were measured and used to calculate the moduli values. The driven frequency was 569 cycles per sec, and a protective helium atmosphere was used. The data, plotted in Fig. 1, show that the modulus decreases in an approximately linear manner with temperature over the range tested.

Jan 1, 1957

By J. B. Clark, A. J. McEvily, R. L. Snyder

The nonuniform distribution of precipitate particles has been recognized as a leading factor contributing to the relatively low fatigue resistance of aluminum alloys. The structure of many of these alloys is characterized by narrow precipitate-free zones adjacent to the grain boundaries. Alloys with such zones exhibit a tendency for brittle inter crystalline fracture. The interrelation between this type of structure and mechanical properties was investigated in an Al-10 wt pct Mg alloy. It was found that deformation during fatigue occurs preferentially along these zones and cracks initiate there. In Al-10wt pct Mg, the zones were found to be supersaturated even after extensive general precipitation and are due to the absence of proper precipitate nuclei in the region near the grain boundaries. Cold working the alloy prior to aging improves the mechanical properties by inducing precipitation within the zones and also by jogging of grain boundaries. The mode of fracture is changed from brittle inter crystalline to more ductile trans granular fracture. THE process of fatigue is highly structure sensitive, with the strength of the whole often dependent upon some localized discontinuity, either geometrical or metallurgical in nature. Much has been learned about the role of geometrical discontinuities, e.g., notches, in fatigue, but with the exception of the effects of inclusions or the shapes of carbides, relatively little is known about the specific effects of discontinuities in metallurgical structure such as nonuniform precipitation. In most age-hardening aluminum alloys, metallo-graphic studies have shown that the extent of precipitation adjacent to grain boundaries is much less than that which occurs in the interior of the grains. The width of these almost precipitate-free regions, which are sometimes called denuded zones, and the extent of solute depletion within them, are dependent upon the particular alloy and its aging treatment. It has been observed1 that these zones are relatively soft with the result that plastic deformation takes place preferentially within them. It has also been shown 2-4 that there exists a tendency for intercrys- talline cracking in fatigue when such zones are present. It is of interest to note that Broom et al.2,3 were able to reduce the incidence of this type of failure in an A1-4 wt pct Cu alloy by stretching the material 10 pct prior to aging. In the present study, the effects of precipitate-free regions on the fatigue properties of an A1-10 wt pct Mg alloy were studied in detail, and the effects of deformation prior to aging on the nature of the precipitation process as well as on fatigue properties were also investigated. MATERIAL AND PROCESSING An A1-10 wt pct Mg alloy was selected for this study, because it was known that well-defined precipitate-free regions along the grain boundaries are readily obtained in this alloy after aging at 200oC.5 The starting materials were 99.998 pct A1 and singly sublimed magnesium of about 99.9 pct purity. The aluminum was induction melted in a graphite crucible, and then the magnesium addition was immersed until dissolved. Chlorine gas was then bubbled through the molten alloy for 4 min to degas the melt, after which the melt was cast at a pouring temperature of 730" to 760°C into a cold, graphite-coated, tapered steel mold. Since A1-Mg alloys are difficult to homogenize,5 special care was taken to obtain a uniform composition. Two-in. cubes were cut from the ingot and heated at 446°C for 30 min. These cubes were then hot forged approximately 35 pct in each of the three cube directions and homogenized for 16 hr at 446°C. Sheet specimens were then obtained by pressing 40 pct and rolling 35 pct per pass with reheating between reduction steps to a final thickness of approximately 0.10 in. The sheet was then solution treated for 16 hr at 446°C and water quenched. The age hardening behavior of this material at 200°C was then determined, and the results are shown in Fig. 1. The age hardening of this alloy when subjected to cold work prior to aging is also shown in this figure. Preliminary work indicated that extensive deformation after quenching was required to affect drastically the precipitate-free regions in this alloy, and a rolling reduction of 50 pct was chosen. For purposes of comparison the following three conditions were studied: a) Solution treated, quenched, and aged 20 hr at 200°C

Jan 1, 1963

By Henry M. Howe

In discussing the classification of iron to-day, we are to leave out of consideration the general division into non-malleable or cast iron and malleable iron, as to the adequacy of which no question has been raised; and to confine ourselves to the subdivisions of malleable iron. This has been classified, according to the extent to which the properties imparted by carbon are present (viz., resilience, hardness,strength, and, above all, the capacity for being hardened by sudden cooling from a high temperature), into (1) wrought iron which cannot be hardened, and (2) steel which can be hardened; and this classification I shall, for briefness, term the carbon classification. Until within a few years all authorities, both metallurgical and general, have concurred in explicitly recognizing the carbon-given qualities, and preeminently the capacity for being hardened, as the essential qualities of steel; this is laid down with clearness by every writer on the subject. For several years this old classification has not been sufficient to meet all our needs, since the genius of Bessemer, Siemens, and, I may add, Holley, has produced wrought iron which has been perfectly melted, and thus freed from certain mechanical adhering impurities. This causes what we call homogeneousness for want of a better word, and gives rise to many important qualities which the old wrought iron had not; qualities universally recognized, though not readily described. I shall, for briefness, style them the fusion qualities, and a classification based on them, a fusion classification. These qualities render the new product so vastly superior, for most purposes, to the wrought iron formerly known, that it is neces-

By Morgan Walker

Intermittent injection of gas in gas-lift pumping is a variation of the common practice in that the gas is delivered to the well for a short period, called the "on time," followed by a period during which none is admitted, called the "off time," instead of being admitted continuously at a constant rate or by intermittent flowing in which it is occasionally delivered to the well in just sufficient quantity to flow off the accumulated head of fluid. The term "gas" is used throughout this discussion but it should be remembered that in so far as the operation is concerned either air or natural gas may be used. The equipment at the well is the same as commonly used in gas-lift installations and gas may be admitted to either the tubing or the casing. It seldom occurs that all the wells on a lease can be pumped economically by intermittent injection from one header. Wells that have flow characteristics which permit their being handled together have their intake lines grouped at a central compressor station. Well groups may consist of two or more wells. The total volume of gas delivered by each group of compressors goes to one well at a time through a quick opening valve, each well connected to the header receiving its charge of gas in turn. Special cases may require a deviation from this arrangement. The distribution of the gas to the different wells is effected by an automatic timing device which operates quick-opening valves on the intake lines. The timing mechanism may be actuated by electricity, liquid or gas pressure, The essential factor in the operation of the timing mechanism is that as one intake valve is closed another must be opened. Water-operated Timing Device Timing devices operate the intake valves either directly, or indirectly by pilot valves. Of the former type one that is operated by water and has given satisfactory service is shown in Fig. 1 and can be made on the lease. The horizontal cylinder is a piece of 10-in. casing about 7 ft. long, closed at each end and free to oscillate about a fulcrum at the center.

Jan 1, 1929

By Sandford S. Cole, John S. Breitenstein

The recovery of over 80 pct of the vanadium values in titaniferous magnetite from Maclntyre Development,Tahawus, N. Y., was accomplished by an oxidizing roast with Na2O3-NaCI addition. Process description is given for leaching of roasted ore and precipitation of V2O5 and Cr2O8 from leach liquor. THE exploration and development of the Mac-Intyre orebody at Tahawus, N. Y., by the National Lead Co. provided a source of vanadium. Analyses of various composite sections of the drill cores of the MacIntyre orebody were made to establish whether or not the vanadium was constant throughout. Ten drill cores were sampled as 50 ft sections, crushed, and a portion magnetically concentrated. The head and concentrate were analyzed for total iron and vanadium. The results on the concentrates indicated that the vanadium is associated with the magnetite and maintains a close ratio to the iron content. The nominal ratio of 1:25:140 of V: TiO2:Fe was found to exist in the concentrates. Typical value for the vanadium in the magnetite both from laboratory concentration and mill production is 0.4 pct. The recovery of vanadium from the magnetite was investigated in 1942 to 1943. The research program encompassed both laboratory and pilot-plant work on sufficient scale to provide adequate data to establish the feasibility of a full scale plant. The recovery of vanadium from various ores has been reported in the literature and has been the subject of many patents. The literature dealing with recovery from titaniferous ore by roasting is quite limited. Roasting with alkaline sodium chloride, sodium chloride or alkaline earth chlorides, and sodium acid sulphate have been claimed in various processes as effective means.1-8 The reduction of the ore, followed by acid leaching, was another method proposed.'-' "he use of various pyrometallurgical processes for recovery of vanadium in the metal or in the slag has also been extensively investigated, but the results had little application to the problem."-" The separation of vanadium values from subsequent leach liquors and vanadium-bearing solution has been the subject of a considerable number of papers and patents. The most practical is by hydrolysis at a pH of 2 to 3 by acidifying a slightly alkaline solution. Data on solubility of V²O5 and V2O4 in water and in dilute sulphuric acid indicated a solubility of 10 g per liter in water.'" Laboratory Results Magnetite Analysis: Adequate stock of magnetite was provided so that the laboratory and pilot-plant operation was on ore representative of the mill production. The ore was analyzed chemically and examined by petrographic methods to ascertain whether the vanadium was present in combined state or as an interstitial component between grain boundaries. No evidence was obtained which would indicate that the vanadium was in a free state as coulsonite.15 The analysis of the ore was as follows: Fe²O³, 47.4 pct; FeO, 29.1; TiO,, 10.1; V, 0.40; and Cr, 0.2. The screen analysis of the ore on the as-received basis was: -20 +30 mesh, 28.8 pct; —30 +40, 18.9; -40 +50, 9.7; -50 +60, 15.1; -60 4-100, 5.9; -100 + 200, 11.2; -200 +325, 3.7; and -325, 7.2. Roasting Conditions: The prior practice indicated that a chloridizing roast with or without an alkaline salt had been effective on other titaniferous magnetites. On this basis roasts with additions of sodium chloride, sodium carbonate and mixtures thereof were investigated varying the roasting temperature between 800" and 1100°C. Since the ore had shown no segregation or concentration of vanadium, the influence of particle size on the freeing of vanadium by the reagents during roasting was determined. The initial work was on silica trays in an electric resistance furnace with occasional rabbling of the charge. Subsequently, the roasting was carried out in a small Herreshoff furnace to establish the influence of products of combustion on the recovery of the vanadium. The laboratory tests showed that this ore required an alkaline chloridizing roast, in conjunction with a reduction in particle size to less than 200 mesh. When roasted in air at 900 °C with 5 pct NaCl and 10 pct Na2CO³, over 80 pct recovery of the vanadium was attained as a water-soluble salt. The presence of alkaline earth elements gave detrimental effects and care had to be exercised to avoid any contamination of the ore or roast product by such materials. The solubilization of vanadium under the various conditions is given in a series of curves in Figs. 1 to

Jan 1, 1952

By W. B. McCarter

Broadly speaking, the year 1934, one of the most active in the history of the Coast, has been both disappointing and revealing. Of the 18 new oil-producing areas, only two have shown the qualities of a first class oil field. Many of the new areas are discouraging for the horizons exploited, because of close association of gas and salt water, and the absence of any appreciable oil zone. In spite of amply fulfilling the expectations of drilling and geophysical development, the year has fallen far short of the results that normally should be expected from such a campaign. In 1934, the Cockfield zone has been disappointing because its exploration down the dip from the Conroe and Tom Ball fields revealed only such distillate fields as Splendora, Eureka, and the great gas-sand thickness at Katy. The zone proved good at Raccoon Bend. Newer Oligocene and Frio fields in Texas, with the exception of Hastings, were also disappointing, as Van Vleck arid Old Ocean attest. The discovery at Dickinson is not startling. The development of Hastings, Tom Ball, Dickinson and the deep zone at Raccoon Bend will be slow. A new strip of prospective territory of minor importance lying inland from the Conroe trend was opened by the Kittrell discovery. During the year 206 unproductive wildcats were drilled on the Texas Coast, compared with 207 during 1933 and 141 during 1932. During 1934, there were 835 oil and gas wells and 229 dry holes drilled in proved fields, in contrast with 1100 in 1933 and 512 in 1932. The past year's production was actually 60,868,260 bbl., or 2,020,764 bbl. less than in 1933. The present annual rate of Texas Gulf Coast production is about 61 million barrels per year. The daily Texas Coast production decreased 5537 bbl., or 3.2 per cent, during the year. The total daily production at the end of the year was 173,598 bbl. Eighteen wildcats opened up new oil and gas pools during 1934, so that there are now 78 active pools and 3753 producing oil wells. The production of the average well is 45 bbl. per day. The price of crude oil was almost uniform in 1934,

Jan 1, 1935

By B. F. Oliver

A levitation zone melter is described which has the necessary characteristics for processing metals of controlled purity. No crucible is required; control of the solidification variables is stable; the environment of the charge is chenzically controlled. Rotation of the solidifying interface and mixing in the liquid by the magnetohydrodynamic stirring produce an eight-fold increase in freezing velocity over former melting units with better resulting solute redistributions. The smooth appearance of processed specimens, resistivity ratios as a hnction of position, as well as a segregation curve, are presented as evidence of smooth continuous solute fransport over distances in excess of ten zone lengths. THE difficulties of the floating zone-purification of higher density metals in large quantities under conditions of lowered surface tension are well known and have hindered fundamental research programs for some time. The inordinate amount of time required to obtain a small reproducible yield of high-quality metal has excluded the use of such material for many important material research programs. However, with the use of controllable induction levitation forces' to accomplish stable liquid zones with nearly flat solidifying interfaces, and with good physical and chemical control of the processes involved, these difficulties can be overcome. A zone melter that is to be used for both high-purity and controlled composition work in metal systems must have the following three characteristics: 1) The process must avoid the use of containers. 2) Physical control of the solid-liquid interface and of the mixing within the liquid phase must be stable. 3) The chemical environment of the melt chamber must be controllable. A description of an apparatus that accomplishes these objectives follows.* APPARATUS One of the basic features that is necessary for good process control of large sections is that the charge, the coil, and the motion mechanisms be within the same chamber. This arrangement permits a close coupling between the work coil and the load, which then provides a good flexibility for adjustments of coil dimensions, for controlling the amount of levitation needed for stable operation at a given power level. An overall view of the melter is shown, with the melt-chamber door open, in Fig. 1. The radiation shields surrounding the single-turn induction coil are of water-cooled copper. The chamber is stainless steel, as are most of the components within the chamber. The control panel for the scanner is located at the immediate lower right of the melt chamber. This panel controls the operation of the scanner. The operations controlled are the interface rotation rate, the stretch-squeeze or diameter control, the up and down scanning speeds, and the induction power. All of the drive motors are constant-torque variable-speed motors. The scanning speeds are set with precision helipots and continuously observed with the voltmeter on the control panel and checked with a mechanical indicator within the melt chamber. The rotation rate is also set with a precision helipot. The up-scanning speeds are 2 to 300 in. per hr.

Jan 1, 1963