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By J. L. Huitt, IM. L. Slusser, E. E. Glenn, M. L. Slusser

This paper is concerned with: (1) an analysis and interpretation of the filtration characteristics of drilling muds on filter paper, and (2) an interpretation of early stage "filtration" on consolidated synthetic porous media, herein referred to as the "surge loss" period. It is shown that water-loss data can be plotted so as to disclose the existence of a surge period, a non-uni-form cake thickness period, and a constant pressure filtration period. The same periods occur during exposure of consolidated porous media to muds. The data on consolidated porous media indicate that: (1) mud particles bridge pores inside porous media during the surge period, and (2) "filter cake" build-up inside porous media occurs during subsequent filtration. The data also show that the surge loss increases with sample permeability and with pressure differential. INTRODUCTION The phenomenon of mud filtrate invasion into porous sands of a drilling well has been recognized for many years.1,2,3,4 Part of API Code 29 is concerned with the filtration testing of a drilling mud to yield data on this subject. In a number of investigations "plastering properties" of muds were studied,5,6,7,8 "plastering" apparently meaning cake forming properties. In such studies the characteristics (thickness, permeability, and toughness) of the cake and the rate at which the liquid phase of the mud was separated from the solids (filtration rate through the cake, commonly referred to as water loss) were measured or at least considered. From the standpoint of its effect on well productivity, filtrate invasion into "clean" water-wet pay sands (i.e., those containing no clay minerals) may not necessarily be a serious problem. An increase in water saturation in the zone immediately around the wellbore would cause loss of oil permeability. However, in such a system, much of this water may be removed by oil production. If filtration occurs into "dirty" sands (i.e., those containing appreciable clay minerals), clay swelling or other mechanisms may cause losses in oil permeability which cannot be overcome by oil production.'.' The phenomenon of mud particle invasion into the pay sand of a drilling well was considered to be a possible serious factor in the early days of rotary drilling. Opinions varied as to whether drilling fluids "mudded up" and "sealed" oil sands. In 1932 Rubel,9 Gill,10 and Parsons," in separate papers, presented differences of opinion together with some laboratory and field data concerning loss of oil production caused by drilling fluid invasion into pay zones. These papers, and the discussions, furnish a large background on this subject and indicate the very clear thinking of many men at a time when petroleum production technology was in its infancy. Jones and Babson,6 and Silent,' experimentally found that the depth to which mud particles invaded water-saturated sand packs was small (no greater than 1/16 in). Arn-quist12 in 1937 observed loss of water permeability due to invasion of mud particles into water-saturated, consolidated, sandstone samples. Williams and Cannon5 studied the filtra-tion properties of drilling muds and mentioned "sludge" which penetrated a short distance into the water-saturated filtering medium (sand pack). Byck5 concluded that formation permeability had no effect on the plas-

Jan 1, 1958

By O. R. Morris, G. L. Hawkes

A galvanic cell, using as electrolyte a fused salt solution of calcium carbide and as electrodes carbon and a Fe-C alloy of known composition, has been set up to study the thermodynamics of Fe-C alloys in the temperature rmzge 800" to 1000°C. Time independence and reproducibility of the cell electromotive force were taken as evidence of the reversible behavior of the cell. Carbon was believed to be present in the electrolyte as the so-called acetylide ion, C;-. The plots of the cell electromotive force us temperature for a specific alloy composition were straight lines within the limits of experimental error. The average Partial molar enthalpy of carbon in iron relative to pure carbon was found to be +10,610 i 93 cal per g-atom C. Thermodynamic analysis of the data has led to the following equation for the carbon activity, ac, based upon pure carbon as the standard state: In ac = In Zc + 10,560/RT + (10.02 + 77O/T)ZC - 2.350 where ZC is the lattice ratio [nC/(nF, - nc )] and T is the absolute temperature. This equalion gives carbon activity values generally slightly lower than those from gas equilibration studies reported in the literature. METAL LOGRAPHIC examination of a polished cross section of the steel anode used in the electrolysis studies of fused salt solutions of calcium carbide by Morris and Harry revealed extensive carburization of the steel by the electrodeposited carbon. This carburization was reflected in the variability, with time, of the applied potential to the electrolysis cell, necessary to maintain a constant current density at the electrodes. This observation suggested the setting up of a galvanic cell of the "alloy concentration" type to study the thermodynamics of some metal-carbon alloys. Cells of this general type have been widely used for the study of alloy systems.2 In view of the availability of published data in respect of the austenite phase of the Fe-C system, it was decided to carry out measurements upon these alloys before proceeding to studies of less well documented systems. The galvanic cell may be written: where [C] is carbon dissolved in iron. The electrolyte was a fused salt solution of calcium carbide, containing some 5 to 10 mol pct of carbide. The cell reaction is believed to be: C(s)-[CI [I1 Carbon forms an interstitial solid solution in iron, with the atoms located in the octahedral interstices. In the fcc crystal structure of austenite there is one octahedral interstice per iron atom. Thus, the lattice ratio, ZC, shown by Gurney3 to be the fundamental concentration parameter in the context of interstitial solutions, is given by: where nc and nFe are the number of carbon and iron atoms, respectively. chipman4 has recently shown empirically the advantages of using this concentration parameter instead of the more usual atom ratio or atom fraction. The cell electromotive force, E, assuming reversible behavior, is related to the carbon potential or the partial molar free energy of carbon in the solid solution relative to pure carbon at the same temperature and pressure, GP at the composition ZC, by the equation: where z is the carbide ion valency and F is the Faraday constant. An activity of carbon, ac, in the solution relative to the value of unity assigned to pure carbon, and an activity coefficient, qC , are defined such that: where R is the gas constant and T the absolute temperature. GF is further related to the relative partial molar enthalpy Hm, and the temperature coefficient of the cell electromotive force, (aE/aT)Zc, by the equations: Measurement of the cell electromotive force thus enables calculation of the relative partial molar thermodynamic properties of carbon in iron, if z is known. At E = 0, the solid solution is in equilibrium with pure carbon. More convenient for many purposes is the standard state based upon the infinitely dilute solution, Henry's law. The relationship between the activity coefficient of carbon based upon this standard state, and that based upon the pure carbon standard state, qC , may be obtained by considering the free energy of transfer of carbon from the latter standard state to the former. The relationship is: where +:H is the activity coefficient of carbon in the hypothetical standard state based on a reference of

Jan 1, 1969

By R. F. Domagala, D. J. McPherson

Iodide zirconium was combined with calculated amounts of ZrO2 or master alloys and arc-melted. Annealing treatments were carried out at 21 temperature levels. Metallographic examination of the heat treated specimens permitted construction of the binary phase diagram from zirconium to ZrO2. Oxygen additions to zirconium raise the transformation temperature as well as the melting point. Features of the diagram include the peritectic formation of beta, the formation of alpha directly from the melt, an intermediate phase ZrOB with a' range of homogeneity, and a eutectic between alpha and Zr02. PHASE relationships in the Zr-0 system were determined in the range 0 to 66. 7 atomic pct 0 (ZrO,). Arc-melted alloys were annealed at temperature levels between 600" and 2000°C. Determination of the phase boundaries was accomplished by metallographic evaluation of specimens quenched from the various temperatures. Incipient melting techniques were used to determine solidus curves, and X-ray diffraction work was employed to study the lattice parameters of the a solid solution and the phase ZrO,. Experimental Procedures Westinghouse "Grade 1" iodide zirconium crystal bar (approximately 99.8 pct pure) was employed for the investigation. This material is substantially free of the impurity inclusions characteristic of most zirconium metal. Previous work has shown it to be the most satisfactory grade for phase diagram studies. The zirconium crystal bar, as-received, was coated with corrosion product from autoclave tests by which its grade designation is determined. The bars were sand blasted lightly, pickled for 1 min in a 20 pct HN0,-5 pct HF aqueous solution, rinsed in water and acetone, and dried. The bars were rolled to about 1/32 in. strip, cut into 10 in. lengths, and pickled again. The material was sheared to approximately Y4 in. squares, cleaned with acetone, and stored for use. Two pounds of specially prepared "chemically pure," and 100 grams of spectrographic grade ZrO, were obtained for the preparation of alloys. The "Specpure" ZrO, was obtained from Johnson, Mat-they Co.. Ltd.. and Titanium Alloy Manufacturing Div. of National Lead Co. supplied the other grade of oxide. The "chemically pure" material (henceforth referred to as C.P. ZrO,) was used for the preparation of all alloys employed in the determination of phase relationships. A limited number of alloys were prepared with the "Specpure" oxide to recheck certain phase boundaries. Analyses of the two grades of oxide are given in Table I. The C.P. ZrOI was received in powder form, not suitable for arc melting. Therefore, this material was compressed to wafers 1 in. in diameter and about Vn in. thick. These were segmented and stored for use. The "Specpure" material, in the form of small granules, was suitable for use in the as-received condition. A nonconsumable electrode arc-melting furnace was used to prepare alloys. A water-cooled copper crucible and tungsten-tipped electrode were employed. The material was placed in the crucible and rapidly melted under a protective atmosphere of helium gas by striking the arc on a tungsten stud and directing it upon the charge material. Details of operation, including drawings of this type furnace, have been published.'

Jan 1, 1955

By E. E. Wark, J. Rogers, I. W. Wark, K. L. Sutherland

SOAPS have been used as collectors for many years, but only in the last eight years have other long-chain paraffin salts been used. It may be anticipated that these newer collectors will be used mainly with nonsulphide minerals, for which the xanthates and similar compounds are of little value. On the other hand, the xanthates are both cheap and effective for sulphide ores and seem likely to retain their present eminence in this field. During 1938 and 1939 two of us (E. E. W. and I. W. W.) commenced a comprehensive investigation of the principles underlying the use of paraffin chain salts as flotation reagents. This research was sponsored jointly by the University of Melbourne and a group of Australian mining companies.[t] A broad, semi quantitative survey was then made of the field covered in the present paper. This was followed in 1940 by further work by one of us (K. L. S.). In 1941 the investigation was taken over by the Division of Industrial Chemistry of the Commonwealth Council for Scientific and Industrial Research, Australia. Discovery of some principles upon which are based the flotation of minerals by paraffin chain salts was followed by their application in the development of processes for the recovery of certain strategic minerals from their ores. Promising results in the flotation of cassiterite from various ores will be described in a subsequent paper. THE PARAFFIN CHAIN SALTS The basic requirements for a "collector" in flotation are that it should form a film over the surface of the mineral to be floated, and that this film should be orientated so that hydrocarbon (nonpolar) groups form the effective surface. When modified in this way, the mineral surface possesses some degree of air avidity. All investigators would agree with Taggart, Taylor and Ince23 that such a film can be produced only if the collector compound contains an active (polar) group to attract it to the mineral surface as well as the nonpolar group. One section of this large class of polarnonpolar compounds is the paraffin chain salts: CH3(CH2) „X where X signifies a polar group that ionizes in aqueous solution. Though the compound can ionize, it may be a weak or a strong electrolyte, and the hydrocarbon chain may be in the cation or the anion (Table I). Many compounds of similar constitution are available, but the usual polar groups are: -CO2Na, -SO3Na, -SO4Na, - PO4Na2, or an aminonitrogen group, the

Jan 1, 1946

By J. Rogers. K. L. Sutherland, E. E. Wark, I. W. Wark

Soaps have hem used as collectors for many years, but only in the last eight years have other long-chain paraffin salts been used. It may be anticipated that these newer collectors will be used mainly with nonsulphide minerals, for which the xan-thates and similar compounds are of little value. On the other hand, the xanthates are both cheap and effective for sulphide ores and seem likely to retain their present cminence in this field. During 1938 and 1939 two of us (E. E. W. and I. W. W.) commenced a comprehensive investigation of the principles underlying the use of paraffin chain salts as flotation reagents. This research was sponsored jointly by the University of Melbourne and a group of Australian mining companies. † A broad, semiquantitative survey was then made of the field covered in the present paper. This was followed in 1940 by further work by one of us (K. L. S.). In 1941 the investigation was taken over by the Division of Industrial Chemistry of the Commonwealth Council for Scientific and Industrial Research, Australia. Discovery of some principles upon which are based the flotation of minerals by paraffin chain salts was followed by their application in the development of processes for the recovery of certain strategic minerals from their ores. Promising results in the flotation of cassiterite from various ores will be described in a subsequent paper. The Paraffin Chain Salts 'he basic requirements for a "collector " in flotation are that it should form a film over the surface of the mineral to be floated, and that this film should be orientated so that hydrocarbon (nonpolar) groups form the effective surface. When modified in this way, the mineral surface possesses some degree of air avidity. All investigators would agree with Taggart, Taylor and Ince23 that such a film can be produced only if the collector compound contains an active (polar) group to attract it to the mineral surface as well as the nonpolar group. One section of this large class of polar-nonpolar compounds is the paraffin chain salts: CH3(CH2)nX where .X signifies a polar group that ionizes in aqueous solution. Though the compound can ionize, it may be a weak or a strong electrolyte, and the hydrocarbon chain may be in the cation or the anion (Table I). Many compounds of similar constitution are available, but the usual polar groups are: -Co2Na, -So3Na, -So4Na, — PO4Na2, or an aminonitrogen group, the

Jan 1, 1947

By E. E. Wark, I. W. Wark, J. Rogers. K. L. Sutherland

Soaps have hem used as collectors for many years, but only in the last eight years have other long-chain paraffin salts been used. It may be anticipated that these newer collectors will be used mainly with nonsulphide minerals, for which the xan-thates and similar compounds are of little value. On the other hand, the xanthates are both cheap and effective for sulphide ores and seem likely to retain their present cminence in this field. During 1938 and 1939 two of us (E. E. W. and I. W. W.) commenced a comprehensive investigation of the principles underlying the use of paraffin chain salts as flotation reagents. This research was sponsored jointly by the University of Melbourne and a group of Australian mining companies. † A broad, semiquantitative survey was then made of the field covered in the present paper. This was followed in 1940 by further work by one of us (K. L. S.). In 1941 the investigation was taken over by the Division of Industrial Chemistry of the Commonwealth Council for Scientific and Industrial Research, Australia. Discovery of some principles upon which are based the flotation of minerals by paraffin chain salts was followed by their application in the development of processes for the recovery of certain strategic minerals from their ores. Promising results in the flotation of cassiterite from various ores will be described in a subsequent paper. The Paraffin Chain Salts 'he basic requirements for a "collector " in flotation are that it should form a film over the surface of the mineral to be floated, and that this film should be orientated so that hydrocarbon (nonpolar) groups form the effective surface. When modified in this way, the mineral surface possesses some degree of air avidity. All investigators would agree with Taggart, Taylor and Ince23 that such a film can be produced only if the collector compound contains an active (polar) group to attract it to the mineral surface as well as the nonpolar group. One section of this large class of polar-nonpolar compounds is the paraffin chain salts: CH3(CH2)nX where .X signifies a polar group that ionizes in aqueous solution. Though the compound can ionize, it may be a weak or a strong electrolyte, and the hydrocarbon chain may be in the cation or the anion (Table I). Many compounds of similar constitution are available, but the usual polar groups are: -Co2Na, -So3Na, -So4Na, — PO4Na2, or an aminonitrogen group, the

Jan 1, 1947

By J. L. SCHUELER

THE writer has reread Mr. Ingalls' interesting article in the July, 1923, issue of MINING AND METAL- LURGY on "The Use of Spelter in Galvanizing." It seems that most writers, in commenting upon coatings of spelter on sheets and wire, dwell upon the thin coatings which these materials carry, and rightly so. However, they seem to forget that until very recently, in the case of wire, the manufacturer did not know how to apply a heavy coating of spelter to the wire, especially if the wire was to be woven into fence or fabricated in some other manner, because heavy coatings of spelter are exceedingly brittle. This is even true in the case of high-grade spelter, but to a lesser degree than with Prime Western. Because of this brittleness, it has been necessary for wire manufacturers to smooth the coating by passing the wire through tightly compressed wiping means of some kind, usually asbestos. This removes all of the excess spelter and allows only a thin coating to remain. The latter, as a rule, is malleable and the wire can be fabricated without material injury to the coating.

Jan 1, 1924

By M. H. Harris

A solution has been obtained to the problem of calculating flow into a cased and perforated well. Equations describing the idealized system were solved by numerical analysis techniques on a high-speed digital computer. Computer experimentation indicated that the results are within 3 per cent of the exact solution. Computed results are presented as an apparent skin effect, on a series of dimensionless working curves. Productivity ratios can be rapidly calculated from these data for the wide range of wellbore and reservoir properties actually encountered in field practice. Any reasonable vertical unisotropy ratio can be included in the computation. Productivities can be calculated for wells perforated in a regular pattern, a single horizontal plane or a vertical line on one side of the casing. Solutions for asymmetrical perforation patterns can he easily obtained from the working curves. Solutions for flow into sells completed with a horizontal notch are also provided. Results show that productivity can be increased by extending perforation penetration. This is especially true for shallow penetrations. The highest productivity is obtained when perforations are arranged in horizontal planes, as opposed to a vertical line on one side of the casing. Four or five perforations in one plane will approach the maximum productivity. The effect of perforation hole diameter is small, and is rioticeable only in shallow penetrations. INTRODUCTION The perforating method of well completion has been successfully and widely used in most producing areas. In the past, the desired perforation results were achieved by simply shooting numerous large holes in the casing. A perforating scheme for an area, or particular well, was established by evaluating two types of experimental data: the well flow index and the productivity ratio.' 3 The well flow index test is a means of determining the relative flow capacity of perforations in a linear system. This test also gives information on the perforation size, shape and hole damage which can be expected under well-bore conditions. However, relative flow data from this test cannot be accurately tarnsformed into the radial wellbore system. Thus, no true indication of the productive capacity of a perforated well can be obtained from the well flow index test. A well productivity ratio is derived from electrolytic models built to simulate perforated wells. Available productivity ratio data 2,3 are limited in that all important variables are not extensively evaluated. For example, data are limited to well radii of 3 and 6 in., and to maximum perforation penetration of 1 ft. Practically no information is available on the pattern of flow into a perforation. The effect of various perforation patterns on well productivity has not yet been determined and the effect of perforation diameter has not been thoroughly studied. Also, it will be shown that this type of electrolytic model data is probably in error by as much as 10 per cent or more. Modern completion techniques such as limited-entry perforating, single-plane fracturing, steam and hot air injection and chemical consolidation of incompetent formations all rely on injection and/or production from a limited type of completion. These completions may consist of several high-capacity perforations or a horizontal notch which is equivalent to an infinite number of perforations in one plane. Proper design of these new completion techniques requires, in part, accurate estimates of a well's productive capacity. Data on perforated and notched well productivity have been determined in this investigation. Results are presented as a function of the pertinent variables. Equations describing the idealized system were solved by numerical analysis techniques on a high-speed digital computer. DESCRIPTION OF PROBLEM PRACTICAL APPLICATION The computed results can be applied to wells which meet several general specifications. An external drainage radius of the well must be known or assumed, but the well need not be drilled on a regular pattern. The well must be cased and cemented through the entire producing interval. And, the casing must be perforated with one or more horizontal planes of perforations. The perforation pattern itself must conform to three geometrical requirements. 1. The perforations in a plane must divide the plane into equal angular segments (Fig. 1). Four perforations per plane would be 90" apart. 2. Perforations in a plane must be directly above or beneath perforations in adjacent planes. For two shots per plane, perforations would lie in the BB' plane (Fig. 1). 3. Horizontal planes must have equal vertical spacing and be separated from the top and bottom of the formation by one half the spacing interval. Single planes of perforations should be in the middle of the formation. This is shown in Fig. 2 where h is the formation thickness in a single plane conlpletion or the spacnig interval in a multiple plane completion. The spacing interval at the top and bottom of the formation may vary somewhat without causing an appreciable error in the productivity calculation if the formation is reasonably thick and there are many horizontal planes of perforations. A special provision has been made to calculate the productivity ratios of wells with uneven spacing intervals, or for the case where a single plane of perfora-

Jan 1, 1967

By B. C. Craft

The outstanding event of the year 1932 in this area was the intensive drilling activity in the Zwolle field of Sabine Parish, Louisiana. More new development work was undertaken and completed than during the previous year. This was due in part to the increased price of oil and in a Includes 19 parishes: Beauregard, Bienville, Bossier, Caddo, Caldwell, Catn-houla, Claiborne, Concordia, DeSoto, Grant, Lincoln, Morehouse, Natchitoches, Ouachita, Red River, Richland, Sabine, Union, Webster. B H. K. Shearer: Oil and Gas Development in South Arkansas, North Louisiana and Mississippi in 1931. Trans. A. I. M. E. (1932) 98, 159. a Includes 14 counties: Ashley, Columbia, Dallas, Drew, Hot Springs, Lincoln, LnFayette, Little River, Miller, Ouachita, Pike, Sevier, Scott and Union. * H. K. Shearer: Oil and Gas Development in South Arkansas, North Louisiana and Mississippi in 1931. Trans. A. I. M. E. (1932) 98, 159. part to the fact that production is below local market demands. Exploration during 1932 resulted in the discovery of a new oil field and a new gas

Jan 1, 1933

By David Keys

THE actual procedure in estimating depth of overburden from mag-netic observations made on the surface will vary with the form of the deposit and any theoretical discussion will apply only so far as the form of the deposit conforms to the mathematical premises on which the theory is based. Since the shapes of natural deposits in the field cannot be expressed rigorously in mathematical form, the best that can be done is to assume some simple form and deduce results. Fortunately many small variations in form produce only slight changes in the estimated depth of overburden, therefore the methods have a definite practical value. For the theoretical treatment, magnetic ore deposits may be divided roughly into three classes, depending upon whether the magnetic anom-alies may be considered to arise from (1) a single magnetic pole, (2) a dike or (3) a magnetic doublet. Particular cases, falling under one or other of these classes, have been discussed by different authors.1-4 In general, it may be stated that when the magnetic effects as measured on the surface are due only to one pole of the body, the other pole being so remote that its effect may be neglected, the resultant anomaly F at any point will vary as the inverse square of the distance r of the point from the pole, which may be expressed mathematically by F = k/r2, where k is a constant. When the deposit occurs in the form of a long, thin dike, the resultant anomaly will be of the form F = k'/r and when the deposit is in the shape of a lens, so that both poles have an appreciable effect on the surface, the result will be similar to that caused by a magnetic doublet, and the form will be F = k'/r3. The particular class under which a deposit falls may be deduced from the results of the magnetic survey. The second class is readily found, but there may be difficulty in deciding between the first and third. Isody-namic contours of both the vertical and horizontal anomalies will often be a good guide in making a correct decision.

Jan 1, 1937

By Oliver C. Ralston

This paper reports the results of the use of salt in some research work carried on during the past 3 years at the Salt Lake City Station of the Bureau of Mines, which is quartered in the University of Utah, whose Metallurgical Research Department cooperates with the Bureau. Only the work involving the use of salt is described. The authors wish equal credit given to J. F. Cullen, C. L. Larson, C. Y. Pfoutz, C. E. Sims, H. C. Neeld, R. W. Johnson, F. G. Moses, N. C. Christensen, and G. H. Wigton, who have all in some way contributed toward the success of this work, while connected with the station in one way or another. Lead Metallurgy Popularly Supposed to be Without Problems In lead metallurgy it is difficult at first to find metallurgical problems, as the prevailing conception has been that lead is so easily concentrated in its various ores and so easily reduced to its metallic form that the only progress possible is that involved in cheapening methods of mining and of reduction. Most of the problems usually considered are of minor nature and do not involve radical metallurgical changes. During the three years of work of the Salt Lake Station, the following classification of problems in the metallurgy of lead has been made: Oxidized Ores. 1. Ores containing only lead. 2. Ores containing lead and silver or gold. 3. Ores containing lead and zinc, with or without silver. Sulphide Ores. 1. Ores of pyrite carrying some lead. 2. Ores of complex zinc-lead-iron sulphides. 3. Complex sulphides containing precious metals.

Jan 1, 1918

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

By O. Hoover, M. Herman, V. V. Damiano

The Jetter and borie' teclznique of determining textures using a spherical specimen has been applied to tlze study of compression-rolled beryllium sheet. Snzall spheres the order of 1 mm in diam cut from the beryllium sheet were autotnatically rotated about tz41o axes using the G.E. single-crystal goniometer. Quantitative pole figures were obtained without tke need to apply absorption corrections. Compression-rolled beryllium exhibited peak intensities ,for (0002) planes of positions tilted 10 deg to the rolling plane and a near random distribution of (1010) planes about the nornal to the rolling plane. TECHNIQUES for determining textures of rolled sheet material are amply described in the literature. The techniques are found to be variations of two basic methods. One due to Decker, Asp, and arker, referred to as the transmission method, utilizes a thin-sheet specimen in which the X-ray beam enters the specimen from one side and the intensity of the beam which emerges from the opposite side is measured. The second method due to chulz,3 referred to as the reflection method, utilizes a thick specimen and the intensity of the beam emerging from the same side is measured. The two rotations of the specimen in the beam are designated a and 8. In order to completely determine the texture of sheet material, it is generally necessary to use a combination of the two methods. The calculations involved in correcting the raw X-ray data for absorption effects and the combining of the data obtained by the two methods are very laborious and time consuming. To avoid the intensity corrections which arise as a result of the changing diffraction volume and path length within the sample other methods have been proposed. The Norton method utilizes a cylindrically shaped specimen cut from the sheet material. Since the rods have rotational symmetry, the absorption correction is constant for rotations about the sheet texture. Jetter and Borie' employed a spherical specimen to analyze the fiber texture of extruded aluminum rods. The spheres were rotated rapidly about the fiber axis to include a large number of grains in the X-ray beam and changes in intensity with respect to tilts of the fiber axis were measured. The absorption correction was constant for all angles and was neglected. The Jetter and Borie' technique finds excellent ap- plication to very fine-grained low-absorbing metals in which the entire sphere volume can contribute to the diffraction volume. In the case of low-absorbing metals, however, serious limitations on specimen thickness occur as demonstrated by Braggs due to de-focussing effects. Peak shifts may occur which negate the assumption that integrated intensities are proportional to peak intensities. These limitations in sphere size to the order of 0.5 to 1 mm for beryllium require that the grain size be sufficiently small to include a large enough statistical sample. The present paper describes the application of spherical specimens less than 1 mm in diam to the quantitative determination of pole figures for compression-rolled beryllium sheet having a grain size the order of 10 p. EXPERIMENTAL 1) Specimen Preparation. Two techniques for spark-machining beryllium spheres were tried. One involved the use of a hollow cylinder as a cutting tool. The tool was fed into the rotating cylindrical specimen as shown in Fig. l(a). The hollow cylinder was carefully aligned such that the axis of the cylinder and the axis of the specimen lay in the same plane and were 90 deg to each other. As the hollow cylinder was fed into the rotating cylindrical specimen, a spherical shape was formed as shown in Fig. 1. Alignment was very critical. Slight misalignment resulted in the formation of a barrel-shaped specimen instead of a sphere. A second technique involved the use of a cutting wheel shaped as shown in Fig. 2 with a groove of the desired radius. A section of the sheet specimen was first turned into a cylinder on the left part of the cutting wheel. It was then shifted to the right and a spherical specimen was turned as shown in Fig. 2. The axis of the cylinder lay in the plane of the sheet. Flats corresponding to the rolling plane of the sheet were used to grip the specimen during the machining operation and these served to identify the rolling plane of the sphere. 2) Rotation of Spec=. The spherical specimen is shown mounted on the G.E. single-crystal goniometer in Fig. 3. The knob A of the goniometer shown in Fig. 3 rotates the specimen about the pedestal axis. These angles have been designated as @ angles. The knob B rotates the specimen about an axis perpendicular to the pedestal axis. These angles have been designated as p angles. A device was made to automatically drive the single-crystal goniometer by means of two flexible shafts connected to the A and B knobs as shown in Fig. 3. The motor system was designed to rotate the knob A, thus rotating the specimen through angles of $I while the B knob remained stationary. After one complete

Jan 1, 1967

By C. G. Dunn

THE present note, which was given in the form of a Research in Progress item,' traces the origin of secondary recrystallization grains produced on annealing a cold rolled bicrystal specimen. The investigation began with the realization that a recently acquired conception for the origin of secondary grains produced on annealing cold rolled single-crystal specimens might require modifications for the case of polycrystalline materials. The stated conception2,3 begins with several conditions to be met by primary recrystallization: 1—a primary re-crystallization structure to consist of many small primaries and relatively few large primaries (diam- eters two or three times the average); 2—a primary recrystallization texture to consist of one strong preferred orientation or component and one or more weak components; and 3—a primary recrystalliza-tion structure-texture combination with some of the large primaries belonging to the weak components of the texture. When these conditions occur, some of the large primaries from the weak components of the texture

Jan 1, 1955

By Philip W. Simmons

THE Colorado Plateau uranium province is in a mining boom rivaling the most colorful days of the early West. The application of scientific skills and the use of modern and novel mechanical equipment, however, is unique. No metal has ever received such concentrated effort from geologists and mining engineers. Moreover, no other metal has had the variety of tools available for finding and mining ores. Radiation detection equipment, bull- dozers, truck-mounted wagon and core drills, jeeps, airplanes, helicopters, tractor loaders, self -propelled 3-wheeled dump cars, front-end loaders and fleets of modern trucks are some of the present-day tools of the uranium prospector and miner. Because uranium is so vital to our national defense, the Atomic Energy Commission has offered many incentives for its mining. Through a series of circulars, the AEC has established base price schedules and various incentive payments. The incentive payments for acceptable ores from domestic mines are: (1) a guaranteed base price of $3.50 per Ib for ores assaying 0.20 pct U3O8 and more; (2) premiums based on grades above 0.20 pct U3O8 as for example, ores assaying above 0.50 pct U3O8 receive $1.00 per lb premium; (3) a development allowance of 506 per Ib of U3O8 contained in ores assaying over 0.10 pct U3O8 (4) an ore haulage allowance of 64 a ton mile for a maximum of 100 miles; and (5) an initial production bonus which may amount to as much as $35,000 in addition to all other payments. The producers have been guaranteed this policy until Feb. 28, 1957. The other four will continue until April 1962.

Jan 4, 1954

By Philip R. Strand

Vermiculite is the name used for those micaceous minerals with a ferromagnesian aluminum silicate composition and the unique property of exfoliating to a low density material when heated. Commercially, the exfoliated products are also called vermiculite, or more exactly, expanded vermiculite. In its exfoliated state, vermiculite serves many markets, chief among them construction, agriculture, horticulture, and general industry. Composition and Properties Vermiculite, in a natural state, has the characteristic mica habit, splits readily into thin laminae, flexible but inelastic. In a mineralogical sense, vermiculite is a hydrated silicate with no exact chemical composition. The structural formula for a macroscopic, trioctahedral vermiculite may be written: [ ] The structure of vermiculite is basically that of a talc, and it could be regarded as a trioctahedral member of the smectite group. Macroscopically, vermiculite displays the prominent monoclinic crystal faces that are commonly marked by lines at 60° and 120°. Hardness varies from 1.5 to 2.8 or more; specific gravities are between 2.1 and 2.8; color is amber, bronze, brown, dark green, or black. When heated quickly to an elevated tempera¬ture, vermiculite expands by exfoliating at right angles to the cleavage, into wormlike pieces (the name vermiculite is derived from the Latin `vermiculare,' to breed worms). This characteristic of expansion, the basis for commercial use of the mineral, is the result of the mechanical separation of the layers by the rapid conversion of contained water to steam. The increase in bulk volume of commercial grades is 8 to 12 times, but individual flakes may expand as much as 30 times. All expansion occurs at right angles to the basal cleavage. Vermiculite may also be expanded by a number of chemical processes such as soaking in hydrogen peroxide, weak acids, and other electrolytes. There is a color change during expansion that is dependent upon the composition of the vermiculite and furnace atmospheres. Heating in an oxidizing atmosphere produces dull gray colors. The iron is generally not oxidized during chemical expansion. The exfoliation of the vermiculite crystal results in large pores being formed between groups of platelets. Thus exfoliation can make available a large increase in void volume without significantly changing the surface area of the platelets. This characteristic is important in the chemical carrier applications of vermiculite. Although there has been much research on the chemical and structural composition of vermiculite, an exact formula and composition cannot be described. This is to be expected since vermiculite derives from a number of different mineral sources. As has been proposed, vermiculite is not a single mineral species, but families of related minerals. Additionally, commercial interest in the end product has resulted in the name vermiculite being applied to the very voluminous, bloated products from calcination of baueritized (bleached) phlogopite. This has also resulted in many names for the specific vermiculite found in a particular deposit. All of this difficulty arises from the nature of its crystal chemistry. Consequently, vermiculite is now thought of as several related variable mineral series rather than a group of related species. The vermiculites have a common silica tetrahedral sheet structure with separating ions. It is now generally agreed that vermiculites must also be regarded as true clay minerals. The properties of the mineral, such as cation exchange capacity, organic complexing ability, and vari-

Jan 1, 1975

By P. E. Landolt

MILITARY necessities and economic scarcities, occasioned by the first and second World Wars, led to the search for substitute materials and new products to meet the demands of advancing technology accelerated by research development. Among others, lithium came to attention. Its chemistry had been studied for a long period, but its general use was quite restricted due to limited known sources of raw material. In World War I, Germany used lithium metallurgically for two principal purposes: 1-hardened lead alloy, B-Metal, for railway bearings as a substitute for lead-tin-antimony alloys; and 2-light strong aluminum alloys, Scleron, in which zinc was largely substituted for copper.

Jan 12, 1951

By R. I. Jaffee, H. R. Ogden

AT the present time, there appear to be two conflicting opinions on the solubility of boron in titanium. P. Ehrlich' has indicated from X-ray diffraction work that boron is soluble in titanium up to TiB0.8 (17.8 wt pct, 44 atomic pct). The X-ray diffraction pattern for titanium was found in compositions up to TiB0.05_0.07 (1.1 to 1.6 wt pct); then, without a phase gap, superlattice lines appeared up to TiB0.8 On the other hand, Craighead, Simmons, and Eastwood' have estimated the solubility of boron in both alpha and beta titanium to be less than 0.1 wt pct, based on results of metallographic analysis. In some recent work done at Battelle, results were obtained which shed more light on the titanium-rich end of the titanium-boron system. Iodide-type titanium and high-purity crystalline boron were used in this investigation. The boron was prepared by hydrogen reduction of boron tri-bromide and deposition on a hot tungsten wire. The alloys were prepared by arc melting in an argon atmosphere of 10 cm Hg pressure on a water-cooled copper hearth. The ingots were hot rolled to strip at 850°C. Alloys containing up to 1 pct B could be hot rolled. Those containing 2 pct or more B could not be hot rolled. Metallographically, it was found that a second phase was present in alloys containing as little as 0.4 pct B, and that the quantity of second phase increased with increasing boron content. This is illustrated in Figs. la and lb, which show the microstructures of a Ti-0.4B and a Ti-1B alloy annealed in argon at 850°C. X-ray diffraction patterns of alloys containing 1 and 5 pct B revealed the presence of extra lines which correspond to the superlattice lines reported by Ehrlich.' However, no evidence was found of a shift in the lattice constants of alpha titanium indicating that there is very little, if any, solubility of boron in alpha titanium. This fact, coupled with the fact that the alloys were definitely two-phase, indicates that the extra lines are not superlattice lines, but are more probably the result of a second phase of a hexagonal structure almost identical in cell

Jan 1, 1952

By N. J. Grant, K. M. Zwilsky, J. T. Blucher

DISPERSION strengthening has been studied in a number of metal-metal oxide systems. To date those pure metals available as fine particles (less than about 5 p) have received most of the attention whereas solid solution alloys, generally unavailable as fine powders, have not been examined in detail. The present work was undertaken as a preliminary study to evaluate combined effects of solid solution and dispersion strengthening. The technique used was that of dry mixing of elemental powders with the oxide, followed by a diffusion treatment to obtain the solid solution. The average particle size of the powders used was: Ni, 3.2 p (1nco B); Mo, 1.3 p (Fansteel Metallurgical Corp.); and y alumina, 0.027 \i (G. L. Cabot, Inc.). The particle size of the metal powders was determined by Fisher subsieve measurements while the size of the alumina was calculated from a surface area determination. Prior diffusion studies on small compacts pressed from mixtures of nickel and molybdenum powders with and without 7.5 vol pct A1203 indicated that diffusion was complete after sintering for 100 hr at 1800" , or 50 hr at 2250", or 20 hr at 2550° F. The progress of diffusion was followed by microstructural examination and micro-hardness measurements. Two observations made during the diffusion experiments were: 1) That diffusion proceeded faster in the presence of alumina, confirming similar findings by Seith and Loepman on "SAP'';4 2) That diffusion at temperatures above 1800°F resulted in coarsening of the alumina in agreement with results of other authors reporting on the growth of alumina in nickel above 1800"F. Similar experiments in the Ni-Cr system using 6 and 20 p Cr powders of 0.7 and 0.025 pct 0, respectively, did not result in significant solid solution formation even after long time exposures at 2550° F. It must be concluded that chromium oxide films around individual particles interfere with normal diffusion. A nickel alloy containing 5 wt pct Mo and 7.5 vol pct alumina was fabricated by dry mixing of powders, isostatically compacting at 30,000 psi, diffusing for 120 hr in dry hydrogen at 1800" F, and extruding at 1950"~ with a 30 to 1 reduction of area ratio. The resulting structure, presented in Fig. 1

Jan 1, 1963

Executive. CHARLES F. RAND, Chairman. JAMES F. KEMP, JOSEPH W. RICHARDS, ALBERT R. LEDOUX, BENJAMIN B. THAYER. Membership. BENJAMIN B. THAYER, Chairman. WALTER R. INGALLS, JOHN H. JANE WAY, JR., JOHN D. IRVING, HERMAN A. PROSSER. Finance. EDWARD L. YOUNG, Chairman. KARL EILERS, JAMES GAYLEY.

Jan 4, 1913