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By E. B. Olds, B. P. Burt

The mines of the Consolidated Gopper-mines Corporation are at Kimberly, in the Robinson mining district, White Pine County, Nevada. The blanket-like ore body is a disseminated copper deposit occurring in monzonite porphyry and, in general, is thoroughly fractured, altered, and soft. Contained in the porphyry ores of the extreme westerly end of the ore body are pendants of hard garnetized limestone. A younger monzonite porphyry underlies the ore-bearing porphyry, which in turn rests on limestone and shale. Block caving is the standard method of mining. Because of the undulating top and bottom contours of the ore body, the main haulage level was selected and driven at an elevation calculated to be the most economic depth below the major tonnage sections of ore. Fig. I shows a general section of the Emma Nevada ore body taken through its long axis, which lies roughly in an east-west direction. Mine openings in either type of porphyry require heavy timbering and constant maintenance and repair, particularly in horizons at or near the ore body contact. Where the ore lies close to the haulage level, slusher hoists and scrapers are used to transport horizontally the ore to the main haulage drift (Fig. 2). For the extraction of high-lying ores, a system of branch raises is used; and the ore is mined by gravity. Slushing methods are used also on the high-lying ore-body fringes. Slusher drifts are often driven from the fringe branch raises that have already served their purpose, in order to minimize the cost of the preparatory work in mining the thinner portions of the ore body (Figs. 3 and 4). When a block of ore is developed and undercut, it is economical to mine it as rapidly as the ore will cave efficiently; and this procedure often presents safety problems because of men with equipment working in a relatively congested area. The single-track main haulage drift is about 11/2 miles long, and lateral haulage drifts are driven under the ore body at intervals determined by the height of the ore body above the haulage level. In order to minimize repair and maintenance, the

Jan 1, 1949

By W. L. Dennen, V. H. Wilson

This paper is a description of the opera-tion and results of a Humphreys Spiral Silt Cleaning Plant at the Powderly Colliery 01 The Hudson Coal Co. during the first nine months of operation and follows a preliminary description given at the .Institute cite Institute in May, 1947, in a paper titled "Preparation of Anthracite Silt for Boiler Fuel in a Humphreys Spiral Test Plant" by H. H. Otto, V. H. Wilson and W. L. Dennen. This plant is considered a full size op-erating test plant and, like all new plants, numerous minor changes in the methods of operation have been made from time to time to secure the results desired. Views of the silt preparation plant and of the screening house are given in Fig I and 2. This plant consists of 48 spirals in 8 batteries of 6 spirals each, 36 of which were to be operated as primary spirals and the remaining 12 as secondary spirals. A brief description of the plant and its operation follows. The only material cleaned at the plant during 1947 was that carried in the underflow from the Thickener which han-dles the Breaker waste water. This under-flow, amounting to approximately 2000 gpm of water and containing 12.6 pct of solids, is pumped to vibrating screens where the plus 3/16-in. material is removed. (Fig 3). This oversize material drops into a pocket from which it is trucked to the run-of-mine tipple for re-preparation.

Jan 1, 1949

Jan 1, 1929

By Walter Remmers

THE fact that gray iron increases in volume, cracks and distorts upon repeated heating and cooling is rather common knowledge. In ingot molds, Diesel engine pistons, carburizing boxes, continuous furnace parts, grate bars, stoker parts, and all castings that are subjected repeatedly to high and low temperatures, the phenomenon of growth presents a vital problem. Ingot molds distort and produce cracks which result in seams or laps and later appear as defects in the finished product. The heads of Diesel pistons frequently fail by cracking in a stellar shape. This is attributed usually to the result of permanent growth. Distortion and change of dimension of furnace parts frequently renders them entirely unusuable. In chain grate stokers, mechanical difficulties frequently are caused by the growth of the links. In proper operation these links should never attain a temperature sufficiently high to start growth; nevertheless, some have grown 1/8 in. on an 8-in. length when improperly operated. Even though the phenomenon is generally known there still exists a deficiency in the explanation of the mechanism of this growth. The field of investigators of this subject has a decided variation in opinion concerning the causes. The problem is of sufficient importance therefore to warrant further consideration.

Jan 1, 1930

By Rex B. McLellan

A simple model for dilute interslitial solid solutions is set up which enables a solubility equation for the equilibrium between the solid solution and the gaseous solute to be deduced. This solubility equation is used to estimate the partial thermody -namic functions of Ag-O and Fe-N dilute interstitial solid solutions from the measured equilibrium between these solutions and the gas phase. It is shown that the partial excess entropy of the solute atom in solution is a vibrational entropy which is due Principally to the oscillation of the interstitial atom and does not arise from electronic or elastic interaction between the solute atoms and solvent matrix. In this work measurements of the equilibrium between dilute solid interstitial solutions and a gaseous phase are used to deduce the important thermody-namic functions of the solid solution with the aid of a theoretical solubility equation formulated from a knowledge of the thermodynamic functions of the gas and a simple model for the solid solution. The quantity of principal interest which is deduced from the equilibrium data is the change in vibrational entropy occurring when a solute atom (u) is placed in an interstial site in the solvent (u) lattice. This paper forms part of a more general study in which the properties of condensed phases are deduced from measurements of the equilibrium between the condensed phase and a gas. Previous investigations have dealt with the equilibrium between krypton and liquid metals,' a pure metal and its vapor,' and dilute substitutional alloys and the vapor,3 and the subject has been popularly reviewed by McLellan.4 In the latter investigation3 the vapor pressures of very dilute Cu-Ag and Cu-Au alloys were measured with a Knudsen cell technique over a large range of temperatures and the analysis of the vapor-pressure data showed that the relative partial excess entropies were large and positive [ds= -Sudk = 30 for Au-Ag alloys and 150 for Cu-Au alloys; these values should be compared to unity, the value assumed for these exponentials in the quasi-chemical theory of solutions]. For many interstitial solutions experimental data is available for the equilibrium between the solution and a gaseous phase, and this can be used to deduce the vibrational entropies of the solute atoms in solution. The general method employed is to calculate the chemical potential of the solute atoms in the gas and equate this to pi, the chemical potential of solute atoms in the solid, which is deduced from a simple model set up for the dilute interstitial solution (in which the solute atoms act as bound oscillators in interstitial sites). This enables a theoretical solubility equation to be set up. In the case of Ag-O and Fe-N solid solutions the solubility c, is found to vary with temperature according to a relation of the type, where PU2 is the pressure of the O2 or Np molecules. Essentially, the theoretical solubility equation enables the parameter A(T), which gives the vibration entropy, and the parameter AH, which gives the energy of solution of a solute atom, to be estimated from the measured variation of solubility with temperature. The solutions treated are dilute enough to enable solute-solute interactions to be neglected so that the partial energy and excess entropy of solution E, and GS are not functions of composition and the configurational entropy is that of a random solution. Large positive values have been found for sxSu this quantity has not been given sufficient consideration in recent work on interstitial solutions and it is felt that the partial thermodynamic quantities of very dilute solutions should be understood before the thermodynamics of concentrated solutions can be fully appreciated. EXPERIMENTAL DATA 1) The Silver-Oxygen System. The measurements of Steacie and Johnson,= using silver foils, indicate that there is a pronounced minimum in the solubility vs temperature curve for O-Ag solutions. Eichenauer and Miiller6 have recently redetermined the solubility of oxygen in silver using a method developed in the investigation of metal-hydrogen systems.7 The solubility determinations were carried out on compact specimens of differing shapes and sizes and the results indicate a much lower solubility than was obtained by Steacie and Johnson with no minimum at 400°C. Subsidiary experiments showed that the erroneous results of Steacie and

Jan 1, 1964

By Floyd Kelley

THE literature of the last decade is rich with information relating to the cause and means of control of grain growth in pure metals, but is deficient concerning the role diffusion plays in grain growth, although during this period many new products that depend on diffusion for their properties and success have been developed. Among these are cementation products, produced by calorizing, chromizing, and carbonizing, or by mixing, pressing, and sintering powdered metals such as Syke's iron-molybdenum die material, Genelite, and Elcon Metal (copper, tungsten) etc. This is a fertile field for new developments, but before it can be util-ized to the fullest extent there must be a thorough investigation of the processes by which diffusion and grain growth take place. Grain growth plays no small part in the process and certainly the physical properties of these products depend largely on the grain size and state of equilibrium produced. The field of investigation does not end here, but may be extended to the effect of diffusion on impurities, segregations and dendrites in the broad field of ferrous and non-ferrous metallurgy. A number of years ago the author investigated several of these cases and noted, with striking regularity, the pronounced effect of diffusion in promoting recrystallization and grain growth. An example of this phenomenon is given in his paper on chromizing1 which contained photomicrographs of large radial or columnar crystals produced by diffusion of chromium in the solid state. Another manifestation of this effect was discussed by Austen,2 who showed the part hydrogen plays in the decarburization of steel and the effect of diffusion upon the grain structure.

Jan 1, 1928

By Henry Phelps Howland

During the last decade no topic has created more interest or received more thought among blast-furnace men than coke. One reason for this is, undoubtedly, the remarkable increase in the use of byproduct coke. Formerly our coke was made at a distance from the furnaces and by a distinct organization. There was little cooperation or development possible under these conditions. Today the situation is greatly changed. Much of our coke is made by the organization operating the furnaces and the coke oven is operated with the primary object of obtaining the best results in the blast furnace. The effect of changing the method of coke manufacture, even in some minor detail, is often felt almost immediately at the blast furnace. There naturally results one of the most valuable assets of the byproduct coke oven, i.e., the possibility of increased blast-furnace efficiency due to close observance and correct operation of the ovens. The results are evident, but often it is difficult correctly to account for them. In attacking the solution of a problem of as much importance as why one coke is better than another, there are facts which should be kept clearly in mind. The author hopes, in this paper, to bring out some points relative to the use of carbon in the blast furnace which will be of value in solving this question. GeÜner's Ideal Working Years ago GrÜner made a statement regarding the use of carbon in the blast furnace, which has been very generally accepted by metallurgical and blast-furnace men. I quote this theory as given by Prof. Richards on p. 248 of Metallurgical Calculations: "From the standpoint of the generation of the maximum quantity of heat in the furnace, GrÜner was right in formulating his dietum of the ideal working of a blast furnace, vie.: All the carbon burnt in the furnaee should be first oxidized at the tuyères to CO and all reduction of oxides above the tuyères should be caused by CO, which thus beeomes Co2."

Jan 1, 1917

By Hjalmar Sjögren

Introduction.............767 Group I. The Ores of the Archean Crystalline Schists.... 770 Distribution............. 770 The Rocks.............770 Structures............772 The Rocks of Norrbotten..774 The Ores.............775 Type A. Apatite.Ores..........776 Type B. Mixed Hematite and Magnetite..777 Type C. Quartz-Banded Ores....777 Type D. The "Skarn" .Ores l..778 Type E. Limestone-Ores,..779 The Origin. of the Ore-Deposits......... 779 Arguments against the Sedimentation Theory,... 780 Concentration and Transformation within the Deep-Seated (Ana-morphic) Zone........783 The Chemical Changes.......784 Transformations in the Surface.Zone....789 The Graingesberg and Norrbotten Deposits,.....791 Analogous Deposits........794 Group II. The Ores of the Porphyries (Keratophyres) ... 796 Kiirunavaara. Luossavaara and TuoIlavaara....797 The Syenite.........799 The Porphyry of the, Foot. Wal1 .....799 The Porphyry of the Hanging-Wal1 ....799 The Ores.........800 The Forms and Dimensions of the Ore-Bodies ..802 Contact-Zones........803 The Genesis of the Deposits .......804 Mertainen and Painirova.......806 Ekatrömsberg..........808 Analogous Deposits,........808 Group 111. Magmatic Seregations in Basic Eruptives,... 809 Taberg in Smaland,.........811 Segregations in Diabase Younger than the Dala Sandstone, . 814 Iron-Ore in Nepheline. Syenite.......815 Ekersund and Soggendal in Norway......816

Jan 1, 1908

By J. H. Yang, K. E. Gray

Results of single-blow bit-tooth impact tests on saturated rocks under elevated confining pressures and zero pore pressure were reported in a previous publication.1 This paper presents an extension of the earlier work to include a study of crater formation during tooth impact on both gas- and liquid-saturated Berea and Bandera sandstones at elevated confining and pore pressures. The basic data obtained were force-time, displacement-time, velocity-time and force-displacement curves during crater formation. Crater volume was also measured and the mode of crater formation determined. Bit tooth geometry, depth of penetration and velocity of impact were held constant. Results indicate that, with pore fluid present in the rock, failure trends from brittle to ductile as pore pressure is increased at constant confining pressure (pore pressure and borehole pressure were equal) For a given rock type, the mode of crater formation was dependent not only upon the nominal effective stress, but also upon the fluid which saturated the rock pore space. When confining pressure and pore pressure were equal (zero nominal effective stress), bit-tooth impact resulted in brittle failure for nitrogen-saturated Berea, and brittle to transitional failure for nitrogen-saturated Bandera; when saturated with liquid both rocks failed in a ductile manner at zero nominal effective stress. INTRODUCTION Dynamic wedge penetration tests have been conducted by investigators in several fields, but the failure mechanism of rock under dynamic stresses is not understood completely. The complex action of drilling bits, even considering the action of a single tooth, may be considered as a combination of drag bit and rolling cutter action. Thus, as a first step in understanding rock breakage in oil well drilling, single chisel impact and rock planing are of fundamental importance. For example, Gray 2 and Crisp3 studied drag bit cutting action at brittle stress states. Simon4 and Hartman5 studied the reaction of rocks to vertical impact by means of drop tests. The depth of penetration, crater volume and force-vs-time curves during crater formation were observed. The significance of indexing single-bit impacts has been noted.4,6-8 Gamer et al,9 reported impact tests on impermeable Leuders limestone at atmospheric and elevated confining pressures. In all cases the tests were accomplished on dry rock and pore pressure was considered to be zero. The importance of both confining pressure and pore pressure on the failure characteristics of rock was described. 10-12 It was found that the yield strength and ductility of porous rock depend on the state of stress under which the sample is tested. The importance of pore pressure on drilling rate in microbit experiments was noted by Cumingham and Eenink. l3 Robinson 12 also pointed out that in drilling the most important parameter in rock failure is the effective stress, where effective suess is defined as confining pressure pc minus pore pressure pp. The effect of pore pressure and confining pressure on rock strength was also noted by Serdengecti and Boozer 14 in strain rate tests, and by Gardner, Wyllie and Droschackl5 in elastic wave studies. Until recently all reported wedge impact studies under simulated wellbore stress states have been conducted on dry rock. Maurer 16 reported impact tests on samples saturated with deaerated water. Borehole and formation fluid pressures were equal in these tests except when mud was used in the borehole. With mud in the borehole and a high borehole-to-formation fluid pressure differential. Maurer observed "pseudoplastic" crater formation. Podio and Grayl reported impact tests on Berea and Bandera sandstone saturated with pore fluids having wide ranges in viscosities. In Podio and Gray's tests, confining pressure was elevated, but pore pressure and borehole pressure were held fixed at atmospheric pressure. The presence of

By D. A. Elgillani, M. C. Fuerstenau

With either sulfonate or oleate as collector, quartz responds to flotation with moderate additions of calcium only at moderately high pH, where some portion of the activator has hydrolyzed to caOH+ . Calculations of the concentrations of various ionic and precipitated species of calcium and collectors suggest that the products of [(CaOH+) (RSO3)] and [(CaOH+)(01-)] determine whether flotation is obtained under specific conditions. Ion products on the order of 10-12 were calculated for both the sulfonate and oleate systems. The activating effect of calcium ion in nonmetallic flotation systems is of considerable interest because of the normal presence of calcium in natural water. As a result, this phenomenon has received quite some attention in the past. Kraeber and Boppel1 showed that quartz could be activated by calcium above pH 10 with sulfonate as collector. The feasibility of selectively separating quartz from hematite with calcium activation at relatively high pH was demonstrated by Clemmer, Clemmons, Rampacek, Williams, and stacy.2 Cooke and Digre3 showed with a bubble pick-up method that the minimum quantity of calcium ion required as activator for complete pick-up of particles occurs at pH 11.5 for an addition of 20 mg per liter sodium oleate. They also showed that larger additions of calcium (10-fold increase per unit decrease of pH) must be added for complete bubble pick-up as the pH is reduced. Schuhmann and Prakash,4 using a vacuum flotation technique, found that quartz could be floated with moderate additions of calcium chloride and oleic acid at neutral pH, providing the metal ion was present in stoichiometric excess over the quantity needed to form the normal soap with oleic acid. They also reported that calcium will function as an activator only in basic media. More recently, Eigeles and volova5 have shown that essentially complete flotation of quartz is obtained with 6 x 10-4 mole per liter calcium chloride and 1.7 x 10-5 mole per liter sodium oleate at pH 11.6. while no flotation is obtained at about pH 10.9 and below. The importance of adsorption of activator and collector at the air-liquid interface is also demonstrated in these systems. The important role that metal ion hydrolysis assumes in quartz activation systems was also demonstrated recently.6-8 A detailed investigation of metal activation in sulfonate flotation of quartz was undertaken in one system7 and yielded a number of interesting and important observations. Quantification of the data of this system7 to the extent desired was not possible, though, because certain species could neither be ignored nor accounted for accurately. These difficulties can be circumvented when calcium is involved as activator. This detailed analysis was undertaken to obtain a more quantitative explanation of calcium and metal ion activation in quartz flotation. EXPERIMENTAL MATERIALS AND METHODS Sodium alkyl aryl sulfonate9 mol wt 450, and pure potassium oleate were used as collectors. All other reagents used were reagent grade in quality, i.e., n-amyl alcohol as frother, KOH for pH adjustment, and calcium chloride. Conductivity water, made by passing distilled water through an ion exchange column, was used in the investigation. Quartz was prepared by leaching the sized sample (48 x 150 mesh) with HC1 until no iron could be detected in the leach liquor. The experimental equipment and procedure were the same as that described previously.6,10 EXPERIMENTAL RESULTS As the presence of precipitates was noted in all of the systems to which ca++ and collector were added, experiments were undertaken to determine the solubility products of calcium sulfonate and calcium oleate using a nephelometer. With this technique, collector is titrated into a known solution, which in this case was 5 x 10-5 mole per liter CaCl2 at pH 5.5. Upon precipitation of the calcium-col lector salt, e.g., calcium oleate, light is scattered and detected

Jan 1, 1967

By J. A. Harrison

The physical composition of coal and the distribution of its physical constituents will partially determine the efficiency of the process chosen for coal preparation. Distribution and concentration of coal macerals will, to a degree, be controlled by preparation processes. A number of preparation processes have been evaluated to determine this interrelation. These evaluations will help provide information needed for the production of coal that meets definite petrographic composition specifications. etrographic composition and degree of coalifica-tion of coal can determine the choice of cleaning processes and equipment used in coal preparation. The purpose of this paper is to present data on studies of the preparation processes of breakage, sizing, cleaning, and blending and to show the effect coal's petrographic composition has on these processes. Herrin (No. 6) and Danville (No. 7) Coals from Illinois were used in these tests. Nomenclature used herein is that approved in the Glossary of the International Committee for Coal Petrology,' based primarily on the Stopes-Heerlen system of classification2 and used in coal petrography laboratories throughout the world. BREAKAGE TESTS Breakage tests of Illinois coals related to petrographic composition have been conducted at various times at the Illinois State Geological Survey. These tests have been classified under two headings -impact tests and compression tests. Impact tests, as the name implies, consisted of breaking the coal by a sharp, sudden force. Impact tests were further divided into fall tests and block tests. Compression tests consisted of applying a constant pressure on a piece of coal until the coal fractured.

Jan 1, 1963

By Ta M. Li

A change in priorities is perhaps the underlying motivation reflective of governments and people in the Far East nations of the Philippines, Indonesia, and Thailand. While in the past, local governments have focused on feeding their large populations, the transfer of modern technology to the agricultural sector has produced record crop years in many of these countries. As a result, agricultural objectives have become more manageable, prompting governments to shift priorities to the accelerated development of their industrial sectors. The basis of any sustained industrialization program, the governments concede, is the development of a vibrant minerals sector.

Jan 8, 1979

By J. J. Kantner

CREEP investigators have made extensive studies to determine the interrelation of stress, temperature and the tensile creep rates of metals. It has been suggested that at small stresses the secondary or constant creep rates obey a simple viscous law. Building upon this suggestion, departure from pure viscosity as stress increases may be expressed mathematically as a consequence of reversibly altered viscosity or "flowability" in the same sense that temperature change reversibly alters viscosity. From the index to alteration of viscosity, a value for the energy of secondary creep may be derived having the magnitude of the free energy of vaporized metal. The suggestion is made that applica-tion of stress alters the energy of secondary creep. Strain energy is argued to be but a minor factor in the energetics of secondary creep. A deformation mechanism involving the large energy associated with secondary creep implies a sort of solid self-diffusion process. Evidence indicates that creep strain above the recrystallization temperature takes place by crystallographically directed self-diffusion at grain boundaries and points of crystal defects. A self-diffusion theory of secondary creep is proposed, embracing the principles of the Dushman-Langmuir theory of solid diffusion. An equation is suggested whereby the rate of tensile creep may be related directly to the physical and struc-tural character of the solid metal.

Jan 1, 1937

America.-Foreman, J. T. Ashland.-Sturdevant, J. C. AItalIa. Henderson, R. M. Bessemer.-Ball, E. M. Maschmeyer, W. L. McKenzie, W. C., Jr. Birmingham.-Abbott, C. E. Aldrich, T. H. Aldrich, T. H., Jr Aufderhaar, H. C. Berg, H. A. Blair, C. S. Bush, M. W. Clark, G. H.

Jan 1, 1923

By Henry M. Howe

This paper may be regarded as a report of progress of an investigation into the influence of prior exposure to different high temperatures, under different conditions, on the properties of steel after it has been cooled completely. The following are the chief divisions: II.—Experiments on toughening manganese-steel by sudden cooling. III.—A study of the critical points of common or carbon-steel, chiefly by examining the spontaneous retardations which occur in heating and cooling it, and by examining the ductility of pieces of steel which have been cooled suddenly from different temperatures by quenching them in water or brine. IV.—A brief note on Osmond's theory. V.—A study of the critical points by examining the ductility of pieces of steel which have been cooled slowly from different temperatures at, above, and below them. VI.—A description of the furnace used, with notes on thermoelectric pyrometry. It remains to throw further light on the questions studied by ascertaining the condition of the carbon and the hardness proper, and by studying the microstructure and the fracture of the many pieces treated. I hope to present later the results of experiments in some of these directions. With few exceptions, the experiments have been performed in my private laboratory. I tender sincere thanks to my assistant, Mr. William Haskins, S.B., on whom most of the labor has fallen, for his zealous and intelligent co-operation; to the Sterling Steel Co. for their extra hard steel, Series 17; and to Mr. Joseph Hartshorne and the Pottstown Iron Co. for their soft basic steel. Series 8, 9,10, and 18 were supplied by Messrs. Spaulding, Jennings & Co., of the West Bergen Steel Works; to them also my thanks are due. The temperature of the pieces treated has been very carefully

Jan 1, 1894

By G. M. Ritcey, M. J. Slater, B. H. Lucas

The recovery of uranium from acid leach slurries by continuous ion exchange, or solvent extraction using sieve-plate pulse columns, is compared. Differences in processing costs are of prime concern and can be related to differences in the unit operations of the two methods, as well as the chemical and physical properties of the slurry. Parameters are defined for the operation of the solvent-in-pulp process and the design of the continuous ion exchange column. Pilot plant operating experience with both recovery systems is described, and an overall assessment of the relative costs is presented.

Jan 1, 1973

By Horace V. Winchell

This paper, embodying information acquired by the writer in his work in connection with the Geological Survey of Minnesota, is presented by permission of the State Geologist. Historical.—On November 16, 1890, the workmen of Captain J. A. Nichols, of Duluth, Minn., encountered in a test-pit on the northwest quarter of section 3, township 58, range 18, west of the fourth principal meridian, the body of soft ore now called the Mountain Iron mine. Hard ore, chiefly magnetic, had been known for many years on the Mesabi range, and explorations made by Mr. E. W. Griffin, of Minneapolis, near the falls of Prairie river in T. 56-24 and T. 56-25, and by John Mallmann, at the Mallmann explorations, T. 59-14, had revealed some hard hematite interbedded with quartzite and low-grade soft ore; but this was the first discovery of merchantable hematite on the range. Captain Nichols had been exploring more or less along the range for some two years. To him and to the Merritt brothers, of Duluth and Oneota, who, unshaken in Faith by the discouraging reports of explorers, miners, experts, and geologists, had persevered in the search for ore, great credit is due for the final success, and large rewards have accrued to them already.

Jan 1, 1893

By J. A. Elias, A. J. Heckler

A simplified method is described for the prepauatior~ of comnposite samples for determination of one quadrant of an X-ray pole figure of a sheet material by the Schulz reflection method. Other special conzposite sampling methods were used to investigate specific areas of the pole figures. Plotting nets for these sampling plans were drawn by a computer. Step-scanning techniques were used to obtain detailed information about specific regions of a pole figure. Satisfactory pole figures were obtained for large-grained (0.5 to 1 in. diam) sheet materials. COMPOSITE sampling techniques for preparing one quadrant of an X-ray pole figure have been reported by a number of authors.'-5 All of these methods are similar in that they use a composite sample prepared by stacking and holding together coupons cut from a sheet material. The schulze reflection technique is applicable to the composite sample so that only minor corrections are needed for defocusing and absorption effects. Also, a relatively large area of a sheet is sampled through the use of multiple cross sectional pieces. In general, sampling methods necessary to obtain a composite-type specimen have been formidable enough to discourage their use in routine pole figure determinations. This paper presents a versatile sampling technique which is simpler than those previously described along with an accurate method for obtaining stereographic plotting nets for any orientation of a composite specimen surface. A step-scanning technique is used to obtain more quantitative determinations of specific regions in pole figures, and the composite technique is satisfactorily applied to determine pole figures of very large grained sheet materials. REVIEW OF PREVIOUS TECHNIQUES Mueller and ~nott' first proposed a technique for obtaining one complete quadrant of an X-ray pole figure by using a sheet sample and six different composite samples in which the individual coupons were aligned and held together by two types of jigs. Data from the seven different samples were overlapped to obtain a single quadrant. ~eieran~ and Lopata and ~ula~ obtained a complete quadrant of a pole figure from a single sample prepared by forming a cube from coupons cut from a sheet. These coupons were bonded together using an epoxy cement, and a cut was made at 54.7 deg to the normal, transverse, and rolling directions of the sheet, Fig. I. The normal direction of the cut face projects into one quadrant of a stereographic projection at equal angles to the three principal orthogonal reference directions mentioned above. X-ray reflection data obtained along a spiral path in physical space could then be plotted on a stereographic net offset 54.7 deg from the normal, as shown in Fig. 2. A rotation about an axis representing the surface normal is designated as a, and a rotation about an axis lying in the plane of the surface is 4. From Fig. 2 it is apparent that a tilting angle of no more than 55 deg @ is necessary to obtain the complete quadrant. ~eber~ devised an improved sampling technique by cutting coupons 45 deg to the rolling direction of a sheet, stacking and bonding these with an epoxy cement at an angle of 54.7 deg to a reference plane, and finally grinding and lapping a flat specimen surface parallel to this plane. An important consideration of this technique and that of Lopata and ~ula~ is variation in the diffracting power of the specimen surface due to the bonding medium. While any composite-type sample will have some such variation due to boundaries between coupons, the problem can be minimized by elimination of the bonding medium and by avoiding prolonged etching times which could lead to significant inter lame llar attack of the coupon faces. EXPERIMENTAL TECHNIQUE We were working concurrently though independently on a technique similar to ~eber's,' but which does not

Jan 1, 1968

Jan 1, 1893

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Jan 1, 1977