Search Documents

By C. A. Hartinagel

During 1941, the total production of crude oil in New York state was 5,185,000 bbl. This represents a small increase over the average for the past five years. From 1921, when the annual production of the state amounted to only 988,000 bbl., there was a regular annual increase in production (excepting one or two years) until the 5,000,000-bbl. mark was reached in 1937, After more than 20 years of oil recovery by flooding methods, it was generally believed, until a few months ago, that the rate of production was nearly at its peak and within a few years the fields would experience a gradual decline as the thicker sands became exhausted and the thinner ones could be worked only at increasing costs. As a result of the present emergency, however, unusual efforts are being made, in spite of higher costs of operation, to increase the output of Pennsylvania grade oil, to which the New York product belongs. Since most of any increased production would be obtained by flooding, and since floods travel slowly, no large increase in production can be expected for some months to come. During the first year, 10 or 15 per cent increase could be obtained, but maximum production, an increase of perhaps 40 per cent, could not be expected until some time during the second or third year. In the Allegany fields, which account for two thirds of the state's oil production, 1246 wells, including water-intake wells, were drilled during the year; 390 more than in the preceding year and 590 more than in 1939. It is evident that much of the best oil territory has already been developed. As producers move toward edge properties and thinner sands, returns will be smaller, whereas costs remain the same or, under war conditions, become higher. It is estimated that at least 60 million barrels of oil is in sight and will be produced from the thicker sands by present recovery methods. In the thinner sands and edge properties, some 35 million additional barrels can be produced at a profit only if prices become higher. In view of the fact that there is little hope of finding new oil pools in New York, one of the future problems of the oil producer will be to obtain adequate returns for increased production costs. The year started with a posted price of $2.15 per barrel of crude. There were five successive price increases until the high of the year was reached at $2.98 on Aug. 14. Eight days later the Office of Price Administration directed that the price be reduced to the June level of $2.75 a barrel, which remained in effect to the end of the year. With rising costs of operation, it is feared that many of the smaller properties cannot continue production unless the Federal price cut is revoked. During the year, Allegany Refiners Inc., a local enterprise founded in 1933, with plant at Bolivar, western Allegany County, increased its refining capacity from 1000 to 1500 bbl. daily. At the same time equipment was added to make the plant a complete lubricating-oil refinery, including facilities for the refining of wax into the finished product. Previous to the enlargement, it was necessary to sell the wax

Jan 1, 1942

By C. A. Hartinagel

During 1941, the total production of crude oil in New York state was 5,185,000 bbl. This represents a small increase over the average for the past five years. From 1921, when the annual production of the state amounted to only 988,000 bbl., there was a regular annual increase in production (excepting one or two years) until the 5,000,000-bbl. mark was reached in 1937, After more than 20 years of oil recovery by flooding methods, it was generally believed, until a few months ago, that the rate of production was nearly at its peak and within a few years the fields would experience a gradual decline as the thicker sands became exhausted and the thinner ones could be worked only at increasing costs. As a result of the present emergency, however, unusual efforts are being made, in spite of higher costs of operation, to increase the output of Pennsylvania grade oil, to which the New York product belongs. Since most of any increased production would be obtained by flooding, and since floods travel slowly, no large increase in production can be expected for some months to come. During the first year, 10 or 15 per cent increase could be obtained, but maximum production, an increase of perhaps 40 per cent, could not be expected until some time during the second or third year. In the Allegany fields, which account for two thirds of the state's oil production, 1246 wells, including water-intake wells, were drilled during the year; 390 more than in the preceding year and 590 more than in 1939. It is evident that much of the best oil territory has already been developed. As producers move toward edge properties and thinner sands, returns will be smaller, whereas costs remain the same or, under war conditions, become higher. It is estimated that at least 60 million barrels of oil is in sight and will be produced from the thicker sands by present recovery methods. In the thinner sands and edge properties, some 35 million additional barrels can be produced at a profit only if prices become higher. In view of the fact that there is little hope of finding new oil pools in New York, one of the future problems of the oil producer will be to obtain adequate returns for increased production costs. The year started with a posted price of $2.15 per barrel of crude. There were five successive price increases until the high of the year was reached at $2.98 on Aug. 14. Eight days later the Office of Price Administration directed that the price be reduced to the June level of $2.75 a barrel, which remained in effect to the end of the year. With rising costs of operation, it is feared that many of the smaller properties cannot continue production unless the Federal price cut is revoked. During the year, Allegany Refiners Inc., a local enterprise founded in 1933, with plant at Bolivar, western Allegany County, increased its refining capacity from 1000 to 1500 bbl. daily. At the same time equipment was added to make the plant a complete lubricating-oil refinery, including facilities for the refining of wax into the finished product. Previous to the enlargement, it was necessary to sell the wax

Jan 1, 1942

By Wolfgang Pietsch

Pressure agglomeration using tableting machines, roll presses, punch presses, isostatic pressing equipment, extrusion presses, and other less common equipment, represents a large share among commercial applications of size enlargement by agglomeration. The paper attempts to classify and describe the equipment and technology, their development and state of the art, as well as their respective applications, advantages, and disadvantages.

Jan 1, 1977

By R. W. Guard

ALTHOUGH etching techniques have been developed for revealing dislocation sites in several metals and ionic crystals,h t is valuable to extend the technique to new metals. An etch pit method for nickel has been developed on the basis some suggestions of Dr. John R. Cuthill of the National Bureau of Standards who had observed etch pits in creep specimens of nickel. The etchant used was proposed first by wensch2 for revealing grain size in nickel. The present paper describes the evidence that the technique can be used to reveal dislocations and gives the conditions under which etching can be carried out. The specimens examined were vacuum melted high-purity Ni (99.985 pct Ni) and commercial "A" nickel (99.8 pct Ni). Both materials contained greater than 0.008 pet C and had been annealed in nitrogen or dry hydrogen at 1100o to 1200°C. This gave a grain size of 1.5 mm in the high-purity nickel and 0.050 mm in "A" nickel. Tensile specimens (0.254 in. diam) were deformed from 0.25 to 10 pct at room temperature and then heated for 1/2 hr at different temperatures from 400" to 900°C. The specimens were sectioned longitudinally then polished electrolytically in 60 pct H2SO4 and etched in 35 pct H3PO4 solution at 0.2 to 0.4 v for 30 sec to 3 min. The best method for setting the proper voltage for etching is to increase the voltage until gas bubbles are evolved vigorously from the specimen and then cut it back by 10 pct. It is necessary to heat the specimen above 500°C after deformation in order that etch pits will be formed. This "decoration" treatment permits carbon to segregate to the dislocation rendering them sensitive to etching. It was demonstrated that carbon was the decorating impurity by decarburizing some specimens in wet H2 at 1200°C. The susceptibility to etch pitting was lost following this treatment but could be restored by carburizing in contact with graphite. Some rearrangement of the dislocations in the as-deformed structure occurs on heating at 500oC and above so that the technique can not be used to study the nature of dislocation patterns in deformed specimens. Extended etching does not change the number of pits although the background becomes rough and the pits quite large. The polycrystalline specimens with various strains were examined after annealing at different temperatures. Typical patterns are shown in Figs. 1 and 2. In the unstrained specimen, Fig. 1, the density of pits is 2.5 X 10' per sq cm. All grains show pits regardless of their orientation although there is a

Jan 1, 1961

By H. Conrad Meyer

The wizardry of nucleonics has added new and greater dimensions to the almost inseparable "twins"-zirconium and hafnium. So close is their relationship that neither element is found free of the other in any presently known mineral. Although zirconium in the form of its oxide was discovered in 1789 by Klaproth, the metal in an impure, nonductile form was not isolated until 1824 by Berzelius. About 100 years later -1925-van Arkel and deBoer developed and patented a technique for the deposition in vacuo of crystalline, coherent, highly ductile metal of extreme purity on an electrically heated filament through the dissociation of gaseous zirconium tetraiodide. Within the past five years both zirconium and hafnium have been dramatized by the press and in popular science magazines. This has led to the false assumption that practically all of the world consumption of zirconium ores is used in the production of the metals. Recent statistics on the subject show that not over 15 pct of the zirconium ore consumed in 1958 went to ferrosilicon zirconium and zirconium metal. The rest was consumed in refractories, foundry sand and facings and ceramics. The importance of zirconium as a component in compact, relatively lightweight nuclear energy units, such as those now used in the submarine Nautilus,6 is well established. A rival of zirconium metal as a casing for atomic fuels is a newly developed ceramic body. It is claimed to be cheaper than zirconium-to withstand higher temperatures-and to be more resistant to corrosion. Whether such ceramic casings have the required low thermal neutron absorption cross section, high strength and easy formability of zirconium is yet to be demonstrated. Hafnium, because of its low order of abundance and its close chemical relationship to zirconium, was not definitely recognized as a new element until around 1923, despite prior claims. A study of the X-ray spectra of zirconium led to its identification. The circumstances leading to the discovery of hafnium were much less fortuitous than those surrounding zirconium. The more precise tools of arc and X-ray spectrometry lent themselves admirably to the search for elements to fill certain gaps in the periodic table. [ ] Pure, ductile hafnium-a metal similar in appearance to stainless steel-has a specific gravity of 13.3 (zirconium 6.52) and a melting point of 2,200°C. In other respects it closely resembles zirconium except in one important respect which gives it a preeminent position in nuclear energy development, namely, a high thermal-neutron absorption cross section. This explains the necessity of hafnium-free zirconium in atomic piles. The ability of hafnium to capture thermal neutrons makes it an excellent "moderator" of "governor" when used as control rods in nuclear reactors (Table 1).

Jan 1, 1960

By F. Louis Grammer

The following study of flue-dirt and the influences controlling it may be interesting to many. It is published because it represents observations at about thirty furnaces at different times. It may assist in giving an impetus to the making of similar observations elsewhere. Until ten years ago, the metallic waste in furnace-gases was not considered a problem of pressing urgency in iron metallurgy—certainly not in the blastfurnace end of it. Many plants at present ignore, or pay but little attention to, top-pressures. Prior to the introduction of Mesabi ore, the losses in escaping gases, if considered at all, were regarded as thermal losses, or losses of fuel (except by those interested in lead, zinc, silver, etc.). In a high-priced material like ferro-manganese, such losses were, indeed, considered important. But the behavior of the Mesabi ores, corning, as they did, in practically inexhaustible quantities, could not be disregarded by the furnaceman. These ores came to stay. The tables appended below have purposely been altered to disguise the plant, the company and the ores used. The comparative values are maintained. In these tables, the influencing elements and conditions which are constant, or practically so, namely, size of furnace, quantity of wind, fuel used, etc., are not mentioned. The figures represent observations consistently followed up for a long period. The weights of flue-dirt were obtained from cars on which no other dirt was thrown. The analyses and calculations are based on the best of sampling. The effects of slips are excluded. Slips should not occur at well-regulated or properly-constructed furnaces, excepting under unusual and rare conditions. Allowances are made for moisture, scrap charged and silicon in the metal. The cutting effect of Mesabi

Jan 1, 1904

George Smith, Sydney, N. S. Wales (communication to the Secretary): The very interesting paper by Mr. Emmons on " The Secondary Enrichment of Ore-Deposits " has just come under my notice; and its reference to my own paper* on " The OreDeposits of the Australian Broken Hill Consols Mine "† is therefore only noted some two and a half years after its publi-

Jan 1, 1903

THE solid nonmetallic inclusions that are present to some extent in all commercial steels have been variously designated. In early references they were usually called slag inclusions, and. this terminology is still retained to some extent. On the premise that all nonmetallic matter produced in a metallurgical process is slag, this can be justified. We have come to think of slag, however, in a more restricted sense, and calling these particles slag inclusions is further objectionable because it fosters the erroneous concept that they are actually incorporated portions of furnace slag. Rarely is this true. The term sonims (coined from solid nonmetallic impurities) was proposed many years ago but never came into common use. In general the term "nonmetallic inclusions" seems to be satisfactory and adequate. NATURE AND CONSTITUTION OF NONMETALLIC INCLUSIONS From the standpoint of origin, inclusions fall naturally into two classes: (1) those that occur as a result of reactions taking place in the body of the molten or solidifying metal and (2) those that result from the mechanical incorporation of refractories or other materials with which the steel comes in contact. The former are by far the more numerous and have been called indigenous, natural, or native inclusions. The latter are by their very nature sporadic in occurrence and have been called exogenous, accidental, adventitious, or foreign inclusions. They are often referred to as the "slag stringer" type, though here also the material is not likely to be furnace slag. Substances Found in Inclusions. Nonmetallic inclusions are composed principally of oxides and sulphidea but carbides and nitrides sometimes play an important role. In the case of indigenous inclusions the reactions by which these particles are precipitated from the molten or solidifying steel may be caused by (1) oxidation such as may occur during refining or during tapping and teeming, (2) deoxidation by added alloys, (3) change in equilibrium constants as the steel cools to the freezing temperature, (4) decreased solubility with lower

Jan 1, 1944

By Dilip K. Das, Douglas T. Pitman

ONE of the major uses of barium in metallic form is as a getter material in vacuum tubes. Because of the high chemical reactivity of the metal, Ba-Al alloys are extensively used. Numerous methods for the preparation of Ba-Al alloys have been published, a few of which1-4 are cited here. Most of these methods were found to be quite elaborate, involving the reduction of BaO, and not too well adapted for the close control of the final composition of small amounts of alloys prepared for laboratory use. A simple laboratory method for the preparation of Ba-A1 alloys in small batches starting from pure metals was devised, so that it was possible to control the desired compositions to within 1 pct. The pertinent features of the alloy system Ba-Al5 are 1) an intermediate compound BaAl, with the melting point of 1050°C, and 2) a eutectic between aluminum and BaAl4 at 98 pct Al. The accompanying sketch shows the experimental arrangement for the preparation of the alloys. Weighed amounts of aluminum and barium were placed in an alumina and a stainless steel crucible, respectively. According to the supplier's specification, the purity of the metals used in the alloys is as follows: a) aluminum rods—99.9 pct Al, and b) barium rods—99.5 pct Ba. The stainless steel crucible, tapered at the bottom and having a 1/16 in. diam hole, rested on top of the alumina crucible. The assembly was placed inside a graphite sleeve which rested on a refractory platform. The platform moved the assembly up and down through the field of a radio frequency coil. A glass bell jar was placed between the crucible assembly and the radio frequency coil to maintain a steady flow of helium around the melt. A small window was cut out on the wall of the alumina crucible to observe the progress of the re- action and to record the temperature with an optical pyrometer. The platform was first raised high enough to move the barium out of the radio frequency coil field in order to allow only the aluminum to melt. The assembly was then lowered so that the barium began to melt and flow out through the small orifice into the molten aluminum. In order to keep the violence of the exothermic reaction under control, the rate of flow of barium was carefully regulated by raising or lowering the crucible assembly. All the samples prepared by this technique were examined by a Norelco X-ray diffractometer using CuKa radiation, The diffraction specimens were prepared by placing the finely powdered samples in flat specimen holders. The Ba-Al alloys prepared with a high barium content were found to consist mainly of BaAl4. The structure of BaAl4 has previously been reported by Alberti and Andress.8 They found that BaAl4 was body-centered-tetragonal with an a0 = b0 = 4.530Å and c0 = 11.14Å. An alloy whose composition was found by chemical analysis to be almost 100 pct BaA1, was used to determine the relative intensities. The d-spacings were obtained from the same alloy to which a small amount of tungsten had been added as a calibrating material. Accurate values for a, and c, were calculated according to the method proposed by Taylor and Floyd.' The calculated values are: a, = b, = 4.566Å and c0 = 11.250Å. The measured d-values for BaAl4 are shown in Table I along with relative peak intensities above background and hkl indices. Acknowledgment The authors are grateful to L. J. Cronin, the head of the Techniques Dept., for suggesting the problem and for his constant interest. References 1Froges and Camargue: German Patent No. 809107, 1951. French Patent No. 935324, 1949. 2E. Bonnier: Annales de physique, 1953, vol. 8, pp. 259-312. 3M. Orman and E. Zemhela: Prac Institute of Metals; 1952, vol. 4, pp. 437-445. 4E. Fujita and H. Yokomizo: Reports Gov. Chemical Industrial Research Institute, Tokyo, 1952, vol. 47, pp. 291-297. 5E. Alberti: Ztsch. fur Metallkunde, 1934, vol. 26, p. 6. 6E Alberti and K. R. Andress: Ztsch. fur Metallkunde, 1935, vol. 27, p. 126. 7 A. Tnslor and R. W. Floyd: Acta Crystallographica, 1950, vol. 3, p. 285.

Jan 1, 1958

By V. H. Gottschalk

THE solubility of gases in metals has been of interest since Graham's time in 1866, but, although the subject was actively studied by iron and steel metallurgists during the eighties, the era of painstaking laboratory investigation begins in 1907 with the publication of Sieverts'1 thesis on the occlusion and diffusion of gases in metals. Since then, Sieverts has worked almost continuously in this field, and his views on the subject are the prevailing ones at the present time.2 Probably the most important result obtained by Sieverts, and frequently verified since by other observers, is the discovery that at a constant temperature the solubility of almost all gases in both the liquid and solid state of most of the metals is proportional to the square root of the pressure (for pressure above 100 mm.). The obvious explanation of this fact is that the gas dissolves as atoms and not as molecules, although it has been pointed out a number of times, first by Donnan and Shawl in connection with their work on the solubility of oxygen in silver at 1075° C., that the formation and solution of a compound of the metal and gas would also be indicated by a variation of the solubility with the square or higher root of the pressure. Sieverts4 himself raised the question whether the usual explanation (i. e., that the gas dissolves as atoms) may not be wrong, when he found that the square root law held also for the solubility of sulfur dioxide in molten copper; in which case dissociation into simpler molecules or atoms does not take place. Stubbs5 subsequently showed that Sieverts and Krumbhaar's "constant" for sulfur

Jan 1, 1932

By S. M. Shelton

SINCE the Saar started. the real progress in scrap-metal recover is in the change of point of view regarding secondary metals. The tendency had been to regard scrap as the normal outgrowth of obsolescence, fluctuating somewhat from periods of depression to periods of prosperity. but nevertheless an unwieldy economic factor more to be contended with than embraced. Now, metals above the ground are being looked upon as semi-permanent reserves or stock piles in various stages of repeated use or revolving life cycles. The change in point of view is due to the forced realization that domestic supplies of new metals are limited and many foreign sources are at least temporarily closed. The stock piles must be cultivated. The reserves must be made more nearly permanent. Steps are being taken : (1) develop methods for recovery of scrap metals heretofore not recovered, and (2) restrict strategic metals to uses ensuring a large percentage of re-use, which in turn means substitute materials in the dissipative uses.

Jan 1, 1942

By M. R. Tek, F. F. Craig, J. O. Wilkes, C. S. Goddin

The waterflood performance of a water-wet, stratified system with crossflow is computed by a finite difference procedure. The effects of five dimensionless parameters on tile oil displacement efficiency, water saturation con-tour.7 and crossflow rates are evaluated in the absence of gravity forces. Crossflow due to viscous and capillary forces is shown to exert a significant effect on oil recovery in a field-scale model of a two-layered. water-wet sandstone reservoir. The crossflow is at a maximum in the vicinity of the front advancing in the more permeable layer. Under favorable mobility ratio conditions, the comparted oil recovery with crossflow always is interrnerliate between that predicted for a uniform reservoir and that for a layered reservoir with no crossflow. INTRODUCTION The important erects of reservoir heterogeneity on waterflood performance are commanding increased attention in the technical literature. Much of this attention is centered on two categories of layered reservoirs: those in which layers are non-communicating and those in which crossflow of fluids occurs between the layers. In the first category, the reservoir is assumed to consist of discrete layers, each uniform within itself and differing from the others only in such properties as thickness, porosity and absolute permeability. The performance within each layer is calculated by one-dimensional flow theory, and the performance of the total reservoir is obtained by summing individual layer performances. Capillary and gravity effects usually are not considered. Representative publications dealing with thi5 type of reservoir are those of Stiles,' Dykstra and Parsons,' Hiatt,3 Warren and Cosgrove' and Higgins and Leighton." Prediction of performance for reservoirs in the second category is considerably more difficult since viscous, capillary and gravitational forces all play important roles in causing crossflow between layers. A number of authors have investigated the simpler problem of two-dimensional displacement flow in a stratified system with a mobility ratio of unity and negligible capillary and gravity effects.'; Others have considered two-dimensional, non-steady-state flow of a single, slightly compressible fluid in a stratified reservoir. A limited number of laboratory oil displacement tests in layered models with crossflow have been reported. Miscible floods (with resultant zero capillary forces) in layered five-spot models were conducted by Dyes and Braun," who studied the effect of mobility ratio with zero gravity forces, and by Craig et al. 12 who studied the effect of gravity forces at constant mobility ratio. Waterfloods in layered five-spot models (with cross-tlow due to capillary, viscous and gravity forces) were conducted by Gaucher and Lindley,"' who showed the effect of gravity forces in causing underrunning of the injected water and by Carpenter, Bail and Bobek, 14 who demonstrated the reliability of Rapoport's" dimension-less parameters for scaling layered systems. Waterfloods in rectangular layered models were conducted by Richardson and Perkins."' who investigated the effect of velocity at constant mobility ratio and with zero gravity forces, and by Hutchinson," who studied the effects of varying mobility, layer permeability and layer thickness ratios. The differential equations which rigorously describe waterflooding in a heterogenous porous medium are non-linear and do not facilitate analytical solution. By using finite difference approximations it is possible to obtain a solution to any desired degree of accuracy. Such a solution, using an alternating direction implicit procedure (ADJP), is described by Douglas, Peaceman and Rachford.18 In the present study, a computer program using ADJP explores systematically the effects of important parameters on waterflood performance of a two-dimensional, two-layered, field-scale model of a water-wet sandstone system. Particular attention is given to evaluation of the water saturation contours and crossflow rates at the interface between layers to gain improved understanding of the crossflow mechanism. PROCEDURE BASIC: FLOW EQUATIONS The basic flow equations for two-dimensional, two-phase, immiscible, incon~pressible flow in a porous medium are:

Jan 1, 1967

By Mark Malamphy

DURING colonial times, Brazil was famous for the richness of her alluvial gold deposits. Paul Ferrand has estimated that the gold produced during the period from 1700 to 1820 was the equivalent of some 64 million pounds sterling. Since that time, most of the more prolific alluvial deposits have been exhausted. A few gold mines are still func-tioning, notably the Morro Velho mine, which is one of the deepest mines in the world. Today, the gold production of Brazil is insignificant when compared with world figures, but there are still many gold-bearing regions and it is probable that in at least some of them profitable returns would result from an exploitation program taking advantage of all the most modern innovations in gold mining and ore treatment on a large scale. In order to demonstrate the value of some of these abandoned pros-pects and stir up interest in increasing the national gold production, the government has stimulated research. Experimental plants have been and are being established in various places, and tests on large quantities of ores are being carried out on a semicommercial basis. The Geological Survey of the State of Minas Geraes is very active in this line and the Federal Institution is also showing an increased interest in the matter.

Jan 1, 1934

By W. B. Mather

GEOLOGICAL studies have revealed the occurrence of hundreds of pegmatite dikes in north- east Brazil, Fig. 1, in the three states of Rio Grande do Norte, Paraiba, and Ceara. Heretofore data have not been available on the possible production of lithium minerals from these areas, and in March, April, and May 1953 the author undertook a reconnaissance survey covering a cross-section of the pegmatites. Sixty-one pegmatites were examined. The pegmatites of Rio Grande do Norte and Paraiba are located in an arid region (Seratao), and except in the most southerly portion there is a mini- mum of vegetation and overburden. The region is easily prospected and relatively accessible by jeep or truck. The pegmatites examined in Ceara are in an area of lush vegetation along the flanks of the Jaqueribe River valley. It is therefore more difficult to prospect, and the dirt roads, as a means of access, leave much to be desired. For all practical purposes rail transportation, except in Ceara, is not available. The rocks of the area1-4 are composed of Pre-Cambrian schist, gneiss, quartzite, and marbles. They have been intruded by granites, monzonites, and diorites and cut by quartz veins and pegmatites.

Jan 9, 1954

By Paul Torrey

THE Northwestern Pennsylvania Oil Producers Association and the United States Geological Survey have cooperated in conducting a pre-liminary study of the character of the flood waters, the relationship of changes in concentration of the salts dissolved in these waters to ultimate flood-oil production, and the original association of oil and water in the Bradford field. Bradford has long been recognized as a dry-sand field. As a matter of fact, there had been little information available on the oil-field waters of northern Pennsylvania until this investigation was undertaken. THE BRADFORD SAND Practically all of the oil produced in the Bradford field comes from one horizon, generally known as the Third, or Bradford, sand. Originally, it was believed that the Bradford sand was equivalent to the Third sand of Venango County, Pennsylvania and the name "Third" unfortunately still persists, although shortly after the discovery of the Bradford pool Carll1 determined that there was a stratigraphic interval of approximately ;000 ft. between the two horizons. The Bradford sand, although varying considerably in thickness and lithology within local areas, is persistent throughout the field. It is of marine origin and, upon both paleontologi-cal and stratigraphic evidence, is regarded as a basal member of the Chemung formation.

Jan 1, 1927

By E. Eichen, G. S. Ansell. L. R. Sefton

A Technique for the Preparation of Thin Films of Two-Phase Alloys Suitable for Use in Transmission Electron Microscopy In order to obtain foil sufficiently thin to permit transmission electron microscopy of two-phase alloys, particularly alloys in which the second phase is present as a very finely dispersed second phase, a technique has been developed to permit the thinning of these materials without either the large degree of pitting present in the electrochemical or chemical thinning process or the slicing of the second phase particles accompanying the mi-crotoming process. The metal or alloy to be thinned is first ground to initial sheet thickness of approximately 0.002 in. by hand grinding on 4/0 emery paper. This starting sheet of material is then reduced in cross section by an air-abrasion technique using an S. S. White dental abrasive unit. This unit consists of a supply of compressed CO, which provides a stream of high velocity gas impinging on the metal surface. Incorporated in the machine is a hopper-type of device in which fine abrasive particles of alumina are introduced into this high velocity gas stream. The abrasive particles are irregular in shape, approximately 30 across. If any particles are introduced into the sample during thinning, they should be readily observable. Impingement of this gas abrasive mixture on the metal surface causes rapid removal of the metal in a rather uniform manner. The rates of metal removal may be adjusted by both regulating the gas pressure and amount of abrasive material introduced into the gas stream. By moving the gas stream abrasive mixture slowly about the specimen or sheet surface, a large area of the sheet may be uniformly reduced to a thickness which is then suitable for use in transmission electron microscopy. Attendant with this metal removal is a result in cold working of the metal surface due to the impingement of the abrasive particles. The resultant foils, therefore, if made from materials which are desirable to view in the annealed condition, have to be subsequently heat treated. If the alloy from which these foils have been made has been initially heavily worked or deformed during manufacture, then no subsequent heat treatment is, necessary as in the case of the SAP-type alloys. Following this initial abrasive thinning technique, the material is then given a final electropolish which is just sufficient to remove any oxide which has formed on the metal surface during the abrasion technique. Care has to be exercised in this technique to make sure that none of the attendant problems associated with the chemical or electrochemical removal process are encountered. An electrolyte solution which has been found suitable for aluminum-aluminum oxide SAP materials is one containing 78 ml of perchloric acid, 120 ml of distilled water, 700 ml of ethanol, and 100 ml of butylcellosolve. The current density used is 1 amp per sq cm and a polishing time of 3 sec on each side of the foil is used. Extreme care must be used in choosing the current density and time to ensure that just the oxide film on the specimen is removed. Times or current density which are greater than this will lead to perforation of the film due to the removal of the A1,0, particles or a complete loss of the film due to complete solution of the matrix. Once the oxide film is removed the specimens must be kept in alcohol until placed in the microscope to prevent any further oxidation. Fig. 1 shows -an electron micrograph at X28,000 of a thin foil of an aluminum-aluminum oxide SAP-type alloy prepared using this technique. The alloy consists of a matrix of commercial purity aluminum containing a very finely dispersed second phase of aluminum oxide flakes. In the electron micrograph, the dark patches are the aluminum oxide particles. The lighter portions of the micrograph are the aluminum matrix. Within the aluminum matrix, the dislocation structure of the alloy is clearly visible. This structure consists of intersecting twin boundaries and single dislocations. No abrasive particles were observed in the samples. In addition, thin films of commercial purity aluminum were prepared using this method and observed in the electron microscope. Here also, there was no evidence of abrasive particles introduced in the samples. The technique presented provides a satisfactory method for the production of thin films of aluminum-aluminum oxide SAP-type alloys for use in transmission electron microscopy where none of the usual thinning techniques appears to be satisfactory.

Jan 1, 1962

By H. D. Mellom

The direction of the optic or "C" axis of a uniaxial metal crystal can be found with the metallurgical polarizing microscope by examining two planes of section on the crystal. Complete orientation of the crystal can be determined if a twin crystal is common to both surfaces of section. Examination of Uniaxial Metals in Polarized Light-Rotation of a uniaxial crystal surface, properly prepared,' shows four extinction positions 90 deg apart, provided that the surface is not close to a basal section. One of these two extinction directions corresponds with the projection of the optic axis on the surface of section. This direction can be found if the 'sign of the rotationr2 for the metal is known. To find the direction of the optic axis, the crystal is rotated on the stage 45 deg from an extinction position. With a crystal of negative sign, to produce extinction the analyser must be rotated towards the optic axial direction and vice versa. All sections, other than basal, of a uniaxial crystal have the same sign of rotation and, since there is no change in sign with wave length, white light can be used for these measurements. U the sign of the rotation is not known the presumed direction of the optic axis can be determined assuming a positive sign. A third section cut normal to the presumed optic axis will show basal extinction if the assumption is correct. It is convenient to use the edge between the two planes of section as a fiducial direction common to both surfaces. The optic axis can be related to this direction. If the above measurements are repeated on the other plane of section and the angle between the two section planes measured, stereographic projection can be used to determine the orientation of the crystal optic axis. Determination of Complete Orientation—The complete orientation of a uniaxial crystal can be determined provided that a twin crystal is common to both surfaces of section, and the twin law is known. The orientation of the twin crystal optic axis can be determined in the same way as for the main crystal

Jan 1, 1962

By William Newnam

THE smelting of galena in the ore hearth has been practiced in many countries for several hundred years with varying success. In the United States the water-jacketed American hearths and the Jumbo hearths have found some favor, in the Missouri lead belt, where large quantities of non-argentiferous galena concentrates are produced. In form and method of operation the ore hearth has changed but little since its earliest conception. A detailed description of the furnace is not needed here; it has been fully described in most works on the metallurgy of lead and in many technical papers. Since its field is restricted to non-argentiferous galena, containing over 68 per cent. of lead, its .use is limited to a few districts; and, on account of certain disadvantages attending its operation, modern sintering and blast-furnace practice has nearly driven it out of the Missouri field. It is not generally known that the cost of producing pig lead is smaller by the hearth method than by sintering and blast-furnace smelting. Yet it is doubtful if any metallurgist knowing this to be true would recommend an American hearth installation-by reason of the disadvantages which will be briefly enumerated. The furnace has been limited to a length of from 4 to 5 ft., requiring for its operation two men working an 8-hr. shift as a maximum. The product per man is small; the work is hot and laborious; and the difficulty of completely removing the dust and fume has made it a notorious source of lead poisoning. Although suitable, for, operations on a small scale a large number of hearths would be required for a plant smelting 10,000 tons of 68 to 70 per cent. concentrates per month; and the number of semi-skilled laborers would be six times the number of hearths-a condition which is prohibitive. On account of the high percentage of dust and fume produced, a large flue and bag-house installation is required and, in the past, the handling and re-treatment of. this dust and fume has been a serious problem.

Jan 10, 1915

By L. K. Jetter, C. J. McHargue

The use of axis charts for representing the texture of cold-rolled thorium sheet was compared with conventional pole figures. Four texture components were deduced from the axis charts and shown to be consistent with the pole figures. It was shown that consideration of the pole figures alone could lead to an apparent component which is the average of two actually present. It was also shown that the spread about the "ideal" textures and the amount of material associated with each could be readily obtained Fom the axis chart method. BECAUSE of the crystallographic nature of the deformation mechanisms in metals, plastic flow results in the alignment of certain crystallographic directions with the primary flow directions. In the study of the "preferred orientation" thus developed, one wishes to discern the distribution of the crystallographic directions with respect to some reference direction, usually a direction related to the fabrication procedure, such as the rolling direction. The pole-figure method, introduced by ever,' involves the plotting of the distribution of the poles of some family of planes on a stereographic projection which places the reference direction(s) at the north pole and/or in the center. By noting the angles between the reference directions and concentrations of poles on several such pole figures, one can deduce the crystallographic directions which are aligned with the reference directions. If the preferred orientation is relatively simple and well-developed, one to three pole figures may be sufficient for obtaining the desired information; if there are several texture components, more pole figures may be needed. A significant improvement in the method of representing the textures in wires and rods resulted from the introduction of the "inverse pole figure" or axis-distribution chart by Harris.2 Such a chart gives directly the distribution of the reference axis relative to the standard stereographic projection. There has been widespread acceptance of this method for the representation of fiber textures, and methods have been proposed for converting observed diffraction intensities into axis densities.2-6 The suggestion by Mitchell and Rowland3 and Jetter, McHargue, and williams5 that sheet textures could be represented as distributions of rolling, normal, and transverse directions have been criticized on the basis that they offer no significant advantage over a combination of two ordinary pole figures and that it has not been proved that sheet textures can be treated as quasi fiber textures.6 If the purpose of a texture determination is to study some property which is related to the orientation of a particular crystallographic plane or direction, then conventional pole figures certainly are sufficient. For example, the distribution of the slip planes in face-centered cubic metals (the (111) pole figure) serves to indicate the variation in mechanical properties of sheet. On the other hand if the study is directed at an understanding of the factors influencing texture formation, it is desirable to know not only the preferred orientation but the kind and degree of spread from it and the relative amounts of material in each component, if there are more than one. Axis charts give this information as well as the orientation distributions. Consider the procedure for deducing a texture component from a pole figure for the (111) planes

Jan 1, 1961

By N. P. Goss

ASTERISM appearing in X-ray Laue dia-grams is an extremely sensitive index of changes in the internal structures of indi-vidual grains of polycrystalline metals. It indicates the existence of various forms of subboundary structure or subdivision within the grain. The present viewpoint is that the grain is made up of lattice blocks having substantially the same size and shape.1-4 When these blocks all assume exactly the same orientation, the crystal is perfect and asterism is absent. Cleaves and Thompson5 observed that the hardness of iron is virtually constant over a range of grain sizes. It is quite possible that the subboundary structure caused this, and that the latter is just as important as grain size itself. While the experiments reported here are not con-clusive, they do support this viewpoint. Metals can, under certain conditions, be prepared entirely free from asterism, but this preparation does not necessarily require long heating or slow cooling, as will be shown here. In this paper a distinction is made be-tween mosaic and distorted grain struc-tures but the difference is only a matter of degree. In a previous paper9 it was shown that the grains can become distorted even during heat-treatment. The block structure exists inherently, even in a perfect crystal; the size and shape of these crystallites, or lattice blocks, varies, depending upon a number of factors. Goetz, for example,7 has shown that a metal before crystallizing from the molten state must go through a paracrystalline phase with oriented groups of atoms about 10-14 to 10-15 c.c., or 10-5 cm. in size.

Jan 1, 1940