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By PAUL P. ZElGLER

Rapid growth of the aluminum industry continued through 1948 with an acute shortage of the metal in all forms marking the year. Estimates based on shipments made during the first nine months indicate that, in 1948, the industry shipped more than two billion pounds of aluminum products or roughly four times the amount shipped in the greatest peacetime year prior to the war. The rapid expansion of the aluminum industry is particularly reflected in the production of sheet. Last year, the industry as a whole shipped an estimated 40 per cent more sheet than was produced in the peak war year of 1944.

Jan 1, 1949

By H.A. Bedworth

AlloTs of copper and silicon have been known for one hundred years or more but the commercial development of this type of alloy has taken place during the past few years. In 1905, Sperry l proposed the use of copper-silicon alloys for springs and other purposes for which copper-tin bronzes were used. Some attention was given to this proposal at the time but no one succeeded in producing a practical alloy containing more than a fraction of a per cent. of silicon. The equilibrium relations of the copper-silicon system were studied first by Rudolfi2 and later by Sanfourche 3 and Corson. 4 The constitution of the system has also been recently investigated by Matuyama, 5 and in the laboratories of the American Brass Co. by Smith. 6 Some of the physical properties of the copper-silicon alloys have been investigated by Norbury7 and by Geiss and Van Liempt.8 Summarizing the results of various investigators of the constitution of copper-silicon alloys, the solubility reaches its maximium value, 6.7 per cent. silicon, between 721" and '782" C. At 852" (1. the solubility is 5.25 per cent., while at 400" C. it is only 4.1 per cent. silicon. The copper-silicon alloy begins to get so hard at about 3 per cent, silicon that it is difficult to manage. It was found by Jacobs that the addition of manganese to this alloy considerably improved the working

Jan 1, 1929

By H. A. Bedworth

AlloTs of copper and silicon have been known for one hundred years or more but the commercial development of this type of alloy has taken place during the past few years. In 1905, Sperry l proposed the use of copper-silicon alloys for springs and other purposes for which copper-tin bronzes were used. Some attention was given to this proposal at the time but no one succeeded in producing a practical alloy containing more than a fraction of a per cent. of silicon. The equilibrium relations of the copper-silicon system were studied first by Rudolfi2 and later by Sanfourche 3 and Corson. 4 The constitution of the system has also been recently investigated by Matuyama, 5 and in the laboratories of the American Brass Co. by Smith. 6 Some of the physical properties of the copper-silicon alloys have been investigated by Norbury7 and by Geiss and Van Liempt.8 Summarizing the results of various investigators of the constitution of copper-silicon alloys, the solubility reaches its maximium value, 6.7 per cent. silicon, between 721" and '782" C. At 852" (1. the solubility is 5.25 per cent., while at 400" C. it is only 4.1 per cent. silicon. The copper-silicon alloy begins to get so hard at about 3 per cent, silicon that it is difficult to manage. It was found by Jacobs that the addition of manganese to this alloy considerably improved the working

Jan 1, 1929

By R. R. Sayers

Ventilation may be defined as the process by which vitiated air of an enclosed or partly enclosed space is continuously replaced by fresh air. Fresh air has been defined as invigorating pure air. Pure dry air at sea level contains the following gases:1 Analysis of Air at Sea Level Per Cent. Oxygen.................................................. 20.94 Nitrogen................................................. 78.09 Carbon dioxide........................................... 0.03 Argon................................................... 0.94 Helium, krypton, neon, xenon, hydrogen, hydrogen peroxide, ammonia, ozone........................................ traces Carbon Dioxide Limit For many years carbon dioxide was used as an index of the purity of the air vitiated by the metabolism of people. It was, however, well known that the untoward effects produced on those exposed to such air was not due to the concentration of the carbon dioxide. It has been found that the untoward effects on the comfort and efficiency of those so exposed are due to the increased temperature and humidity. It has been found that men can breathe air containing many times the amount of carbon dioxide found in our worst ventilated theaters and assembly halls, which, according to Rosenau, do not contain above 0.5 per cent, carbon dioxide. Nevertheless, in mines it sometimes occurs in sufficient quantities to cause symptoms in men or even unconsciousness and death. One-half of 1 per cent. of carbon dioxide in normal air causes a slight and unnotice-able increase in the ventilation of the lungs, that is, a man exposed to one-ha,lf of 1 per cent. of carbon dioxide will breathe a little deeper and a little faster than when in pure air. If 2 per cent. of carbon dioxide is in the air, the lung ventilation will be increased about 50 per cent.; if there

Jan 1, 1927

University of Alabama University, Alabama Mining and Metallurgical Society WILLIAM R. HIGGS, President ROBERT E. MEAD, Secretary J. R. CUDWORTH, Faculty Sponsor MILTON H. FIBS, Counselor University of Arizona Tucson, Arizona Miners' Society LEE BLESSING, President R. W. CORY, Secretary E. P. MATHEWSON, Faculty Sponsor B. R. HATCHER, Counselor University of California at Los Angeles Los Angeles, California Student Chapter, A.I.M.E. ARCHER WARNE, President ROBERT JOHNSTON, Secretary E. K. SOPER, Faculty Sponsor EMILE HUGUENIN, Counselor Colorado School of Mines Golden, Colorado Student Chapter, A.I.M.E. J. Ross REED, President ANDREW PERRY, JR., Secretary J. BURNS READ, Faculty Sponsor A. W. NEWBERRY, Counselor

Jan 1, 1936

By Zay Jeffries

AMONG the various metals with low specific gravity, two, aluminum and magnesium, are used in the nearly pure state or as bases for light-weight alloys. Although the production of magnesium is only about one-twenty-fifth that of aluminum, a higher percentage of its output is used in the transportation industry than that of any other metal. The per-centage varies from year to year but, on the average, more than three-fourths of the magnesium production has been used for this purpose. In the United States, about 40 per cent of the aluminum production is used for transportation purposes. It seems obvious that equipment demanding repeated movement with need for rapid acceleration and deceleration should be as light in weight as the economics of engineering materials will permit. There are, however, differences of opinion with reference to both the economics and the engineering aspects of this subject. Tables 1 to 7 inclusive relate to the principal light-metal materials currently used in the transportation industry. These, with the accom-panying titles and footnotes, are in the main self-explanatory. Although the variations in mechanical properties can be easily seen from the tables, it should be kept in mind that the values given are for ordinary tempera-tures and that the changes in properties with temperature are not the same for the different alloys. Also, the corrosion properties cannot be deduced accurately either from the compositions or from the physical properties. Again, certain of these alloys are used because they possess desirable combinations of properties not listed in tine tables, including heat conductivity, coefficient of expansion, machinability, ease of casting or working, light reflectivity, anodic coating characteristics, etc. These, together with variations in prices, must be given careful analysis to effec-tively utilize the light alloys. Some of the alloys listed in the tables are new and some are old, but all are standard. Even the older alloys are available in new shapes and larger sizes than heretofore, and all are used in the transportation industry in structures of new design. Certain of the applications of specific alloys will be touched upon in the following brief history of the use of the light metals in transportation.

Jan 1, 1936

By J. O. Mack, J. B. Russell

IN recent years, solders containing 20 per cent tin with no bismuth or cadmium have been developed by a few companies, and personnel have been properly instructed in their use. In addition, since the tin shortage, a number of solders containing less than 10 per cent Sn, and some with no tin, are being used in special applications; however, a solder of this type has yet to be developed that is satisfactory for general use. [ ] The purpose of this investigation was to develop an alloy containing a maximum of 15 per cent tin, with no cadmium or bismuth, having solder properties equivalent to or better than those of substitute solders now specified containing i8 to 20 per cent tin (Table I), or even approaching the properties of the standard 40 to 60 tin-lead solder. The wartime restriction of bismuth and cadmium, elements that have beneficial effects on fluidity, solidification range and strength, makes it increasingly difficult to develop a general-purpose solder containing a maximum of 15 per cent tin. In the course of this investigation, 11 elements were used in various combinations with the basic 15-85 tin-lead alloy. These elements were antimony, silver, copper, indium, thallium, lithium, calcium, barium, potassium, sodium and arsenic. In all, 116 low-tin solders were investigated, with the idea of developing a solder that will give satisfactory working properties, specifically in regard to "wetting" of copper, brass and iron, solidification range, capillarity and shear strength of a soldered joint. The relative importance of these various properties plays an important role in the search for substitute solders, since it is almost impossible to retain all of the desired qualities of a high-tin solder and still make drastic changes in the alloy composition. Because of the expected uses of a general-purpose solder, it is necessary that it have properties, especially in regard to wettability, that will enable it to be used on the metals in common use. BASIC CONSIDERATIONS The maximum liquidus temperature of a solder is determined by the particular application involved and the temperature that can be obtained by the source of heat.

Jan 1, 1944

By Hugh Marriott

MANGANESE and its ores have been recently dealt with in comprehensive papers to the Iron and Steel Institute by Sir Robert Hadfield, and in a series of papers read before the A. I. M. E. at the Cleveland meeting. I have taken the opportunity of adding this mineral, to my records of the "World's Mineral Production and Consumption," as recently pub-lished in the Economist ?. The tables bring out the following significant facts: The world's production has increased by 10 per cent since 1913. India's production has increased by 3 per cent since 1.913, the supply from this source now being 31.1 per cent of the world's output. Russia is now producing at about half its pre-war rate and yields 19 per cent of the world's production. West Africa supplies 12.5 per cent of the world's total output. Brazil's present output is 2.5 times that of the pre-war period, being 11.3 per cent of the world's output.

Jan 9, 1927

By G. F. Huff, G. R. Bailey, J. H. Richards

An improved bomb-sampling technique for obtaining samples for oxygen analysis from liquid steel is described. Analyses of samples taken from open-hearth furnaces by the improved method show sufficient agreement with laboratory data to indicate the accuracy of the method is better than that of other existing sampling methods. THE bomb-sampling method of determining the oxygen content of a liquid-steel bath was studied by obtaining and analyzing more than 200 samples from normal open-hearth heats. Of these samples, about 60 were obtained with a bomb of conventional design;' the remainder were taken with a somewhat modified bomb designed to give greater protection against slag contamination. In the new device, the contacting faces of the cast-iron mold halves are machined so that they fit closely; the opening at the top of the bomb is covered with a thin steel cap; and the top of the bomb is further covered with a wood block held in place by heavy steel wire. After the bomb has passed through the slag layer and has entered the steel bath, the wire melts and the wood block floats to the surface. Thereafter, the steel melts through the thin cap and flows into the bomb cavity where it is deoxidized with aluminum wire. An assembled bomb, ready for sampling, is shown in Fig. 1. To standardize sampling procedure, the samples were usually taken through the center door and at the bottom of the furnace; that is, the bomb was on the bottom when the metal cap melted. After each addition to the furnace, at least 20 min elapsed before a sample was taken. The oxygen contents of all the samples were determined by using the vacuum-fusion method, two or more specimens from each sample being analyzed. The specimens were cubes of metal cut from a region in the interior of the bomb sample, as shown in Fig. 2. Drillings for carbon analysis were obtained immediately above the oxygen-analysis region. Reproducibility of Results In determining the reproducibility of the results obtained with the modified bomb, the following four factors were studied: 1—variation in the oxygen concentration of duplicate specimens taken from a single sample; 2—variation in the oxygen concentration of duplicate samples taken in quick succession: 3—effect of the amount of aluminum wire

Jan 1, 1953

By P. Schwarzkopf, J. H. Brophy, J. Wulff

A constitutional diagram has been proposed for the tantalum-rhenium alloy system. Rhenium dissolved in tantalum up to 48 wt pct, and the maximum solubility of tantalum in rhenium is 5 wt pct. Intermediate x and s phases were found. X-ray diffraction, metallography and melting points were employed. SEVERAL investigators have described the phases present in the tantalum-rhenium alloy system, but no detailed account of the phase diagram prior to the present investigation appears to be available. Greenfield and Beck' reported the solubility of 48 to 54 at. pct Re in tantalum, a s phase at 41 at. pct Ta, and x phase isomorphous with a Mn from 37 at. pct Ta to less than 25 at. pct. They employed as-arc melted specimens and heat treatments at 1200 °C lasting 72 hr.2 Duwez3 reported the existence of a a phase at the composition Re3Ta2. Niemiec and Trzebiatowski4 observed a lattice parameter a = 9.69A, for the x phase at a composition Ta7Re22, but no s phase. Savitiski and Tylkina5 have shown a hardness maximum at the composition 40 at, pct Ta and a somewhat lower plateau from 35 to 10 at. pct. Knapton6 indicated results similar to those of Greenfield and Beck.' The present investigation describes the phase relationships in the tantalum-rhenium alloy system determined by melting point measurements, X-ray diffraction and fluorescence, and metallography. EXPERIMENTAL PROCEDURE Commercial 99.7 pct Ta powder from Fansteel Metallurgical Corp. and 99.9 pct Re powder from Chase Brass and Copper Co. were used for alloy preparation. The powders were weighed to desired nominal compositions and then pressed without binder into compacts weighing 5 or 10 g. The compacts were arc-melted six times on alternate sides on a water-cooled copper hearth using a nonconsumable tungsten electrode in an atmosphere of titanium gettered helium, at a pressure of 500 mm Hg. In most cases this procedure yielded alloy buttons of satisfactory homogeneity. A series of alloy specimens were analyzed wet chemically for use as standards for X-ray fluorescence. All specimens were analyzed by fluorescence and the results showed that the compositions differed by less than 3 pct Re from the original as-weighed nominal composition.* On the basis of self-

Jan 1, 1961

By Benjamin Talbot

The problem of segregation and cavities in steel ingots is a subject which has given and is still giving metallurgists, engineers, and operators matter for serious consideration. This question has come more into prominence lately in the United States, due largely to the desire of railroad engineers to secure a better rail than they have obtained ill the past, as the service they demand is increasing in severity; and no doubt manufacturers will be able to meet what is required of them. The rails here are as good as those made in other countries, but the conditions of service and the extremes of climate are more Revere and consequently more breakages occur. Various reasons have been advanced to explain why rails may not be as good in quality to-day as in the past. Some engineers consider that modern methods of manufacturing, designed chiefly to obtain large output, tend to reduce the standard of excellence of more deliberate methods. Others think that 4-ton ingots are worse than those of 2 tons. Again, it is stated that the 100-ton heat in one ladle is too large, and is a step in the wrong direction in casting. My experience upon the question of the size of the ingot is that in rolling rails of from 85-to 100-lb. sections, the range of ingot is only practically such that the difference in the size does not help in the question of segregation, cavities, or blow-holes. I call attention to two ingots from work done at Pencoyd, Pa., 16 years ago. These ingots were bottom-poured, cast at the same time from the same center-runner, the one being 20 by 24 in. and the other 13 by 16 in. in size. The steel was acid open-hearth, and contained C, 0.43; P, 0.062; S, 0.069 per cent. At the same place in each ingot where seg-

Jan 1, 1914

By D. W. Lillie

Property changes produced by irradiation of Al-0.4 wt pet Li alloys at 270°C to a burnup of 0.155 pct of all atoms are described. Metallographic evidence of the formation of internal pores and the concentration of gases at grain boundaries is shown. Some conclusions are drawn concerning desirable property characteristics for resistance to radiation swelling. RADIATION induced gases are of great practical significance in nuclear engineering since they affect the behavior of fissionable fuels and control rod materials. In fuels the gases xenon and krypton are the major offenders, producing serious em-brittlement at low irradiation temperatures and gross swelling at high irradiation temperatures. In control rod materials containing boron, the production of helium from the B 10 (n, 0) Li7 reaction produces similar reactions. Since the trend in reactor design is for operation at increasingly high temperatures, the phenomenon of high-temperature swelling by these induced gases has been the subject of considerable recent study. The objectives of such work have been to obtain engineering information and quantitative data on the effects in specific fuels and control rods and to obtain further understanding of the mechanism of gas damage so that more intelligent corrective steps can be made. Analogue systems are often useful for the latter objective and in this case alloys containing Li are suitable in view of the reaction Li6 + n - He4 + He 4. Both products are gases and no serious radiation problem is produced to complicate post irradiation handling. Considerable caution is, of course, necessary in any operations in which tritium release is possible. The present program was initiated to provide a detailed study of the effects of He + H3 generated by irradiation in Li-bearing alloys. The results on Mg-Li solid solution alloys have been reported elsewhere.' This paper presents information on irradiation of an A1-0.4 pct Li alloy in which the lithium was present as highly enriched Li6 in order to maximize the radiation burnup. PROCEDURE The original intent in the selection of the alloy content was to have Li in solid solution at all temperatures. It became apparent, however, that the solubility of Li in A1 was substantially lower than that reported in the original reference consulted.' This was substantiated by the work of Nowak3 who reported solubility of less than 0.01 pct Li at 100°C. The alloy used (0.4 pct Li) was therefore two phase at room temperature. The irradiation temperature was estimated to be about 270° C, and at that temperature all or almost all of the Li would be soluble under equilibrium conditions. The precise state of the alloy under irradiation is not known. Aluminum used was 99.996 pct purity (max. impurities Si 0.002 pct, Mg 0.001 pct, Fe 0.0005 pct, and Cu 0.0005 pct). The lithium was obtained from Oak Ridge National Laboratory; 96.1 + 0.1 pct of the lithium was ~i~, but chemical impurities were 0.25 pct Ca, 0.05 pct Fe, 0.02 pct Na, 0.02 pct Cu, 0.01 pct Sr, and 0.01 pct Ba. The two metals were melted in an alumina crucible in a resistance heated furnace in an atmosphere of helium. A l-in. ingot was cast in an iron mold, machined to %-in. round, hot swaged (350°C) to 0.080-in. round, cold swaged to 0.060-in. round, and finally cold drawn to 0.040-in. round. Four-inch wire lengths were then cut and annealed at 250°C for 4 hr in helium. Irradiations were carried out in a VT hole in the Argonne CP-5 reactor. The wires were held in an aluminum jig, sixteen wires per capsule, and were maintained in a helium atmosphere for maximum heat transfer. Eight wires of pure aluminum and eight of Al-Li alloy were placed in each capsule. Argome Laboratory statements were accepted as establishing flux and exposure levels. These were based on previous experience and flux map-

Jan 1, 1961

By John Nunes, Frank R. Larson

Temperature-dependent functions of various ten-sile flour stress and fracture parameters were investigated on iron and low composition alloys of Fe-C, Fe-Cr, Fe-Mn, and Fe-Ni. Data were obtained over a range of test temperatures from 200" to -196"C at an initial strain rate of 0.01 min". It was found that the strain-hardening exponent, n, for the Fe-Ni alloys increased significantly at very low testing temperatures with increased alloy addition. Also, the stress and strain at fracture followed a predictable transitional type of behavior. The flour stress-temperature dependence was evaluated employing the relation: M where it is shown that composition can strongly influence the constant M. An empirical formula describing this effect is as follows: M = MI (equivalent at. pct Ni)-'" Some preliminay, tests were run on several commercial steels to test the generality of this relationship. One of the phenomenological explanations of the ductile-to-brittle transition encountered in bcc metals is based upon the difference in the temperature dependence of the flow and fracture stresses.' It states simply that the fracture stress is relatively insensitive to temperature and that the yield or flow stress rises rapidly with decreasing temperature so that, when the flow stress reaches the fracture stress, brittle fracture occurs without appreciable plastic deformation. This behavior is illustrated schematically in Fig. 1 where the ductile-to-brittle transition is shown to occur at two possible temperatures. The lowest temperature, TB, represents essentially completely brittle behavior while the higher temperature, TN, represents "notch" brittle behavior. Support for this theory is obtained when it is observed that fcc metals, which do not commonly have a ductile-to-brittle transition, also do not commonly exhibit any strong temperature de- pendence of the yield stress. This relationship of yield or flow stress behavior with the ductile-to-brittle transition has been generally observed for most metals representative of these two crystallo-graphic structures. One exception to this generalization appears in the case of tantalum where no apparent ductile-to-brittle transition has been observed. However, this may simply be an indication that this type of behavior is not directly related to the flow stress and that some other mechanism such as twinning must also be operative. A comparison of the typical temperature dependence of the yield stress of some representative metals is shown in Fig. 2. In the study of the temperature dependence of the strength of metallic materials, considerable ef-

Jan 1, 1963

P. W. BRIDGMAN.-Owing to a misunderstanding, I did not see Dr. McAdam's and Dr. MacGregor's remarks on my paper on Flow and Fracture (Metals Technology, December 1944, Pp. 32-38), until after their publication. Both Dr. McAdam and Dr. MacGregor speak of my analysis for the stress distribution at the neck of a tension specimen as containing several assumptions; in particular, that the strain is uniform across the section of the neck, that there is no hoop tension at the periphery, and that the plasticity conditions of von Mises hold. As far as the mathematics goes, the situation is no different in this problem of plastic flow than in a conventional problem of elasticity. That solution is unique which satisfies the boundary conditions on the stresses, the stress equations of equilibrium, and in addition the constitutive equations connecting stress and strain in the elastic case, or a corresponding set of equations, of which the von Mises relations are a special form, in the plastic case. In the particular case of the necked tension specimen I have found that there is a solution satisfying the boundary conditions, the stress equations of equilibrium, and the von Mises plasticity conditions in which the strain is uniform across the section, and there is no hoop tension at the periphery. This is therefore the solution, and the uniformity of strain and vanishing of hoop tension at the periphery are to be described as discoveries, over which the operator has no control, rather than as assumptions. The only part of the solution that can properly be described as an assumption is the von Mises plasticity condition. With regard to this it is to be noted that the condition is needed only in a much weakened form, for the analysis uses the condition only at the neck, where the strain is approximately constant. Thus, in the extreme case referred to in a footnote of my paper (p. 37, Met. Tech. Dec. 1944) the actually measured strain across the section varies from 2.4 to 2.6. Obviously it is a much weaker assumption to postulate that the von Mises condition holds in the strain range 2.4 to 2.6 than to assume it to hold for the entire range of strain from o up to 2.6, which would be necessary if the solution applied to the entire tension specimen rather than to the immediate region of the neck only. Furthermore, it is to be commented that under the special conditions of this problem the von Mises condition becomes identical with the maximum shearing-stress criterion of plastic flow; this amounts also to a weakening of the restrictions imposed by the von Mises condition. Dr. MacGregor refers to actual experiments of his own in which the strain was found not to be uniform across the neck. It is to be emphasized, however, that these were experiments on bars of rectangular section, and that the nonuniformity established was a nonuniformity around the perimeter, not a nonuniformity from the surface toward the axis. My method of solution applies only to a circular cross section. It can be said that the solution that satisfies the boundary conditions, etc., would definitely not be expected to demand a uniform strain for noncircular sections. In discussing my results, Dr. McAdam uses a definition of "flow stress" different from mine, so that the immediate applica-

Jan 1, 1945

By B. H. Caudle, A. R. Khan

The oil production performance of thin-oil-column type reservoirs producing entirely by natural water drive are discussed in this paper. The dimensionless production histories were obtained in a series of scaled porous-medium laboratory-model tests under varying effects of rate of production, mobility ratio across moving boundary, ratio of oil- and water-sand thickness and mobility ratio across fixed boundary including the effects of different residual oil saturations in the water-invaded regions. This scaled-model study of thin oil columns indicated that greater recovery of oil results for lower values of the following: rate of production, mobility ratio across the moving boundary, water-sand thickness relative to the oil-sand thickness, and mobility ratio across the fixed boundary or residual oil saturation in the water-invaded region of oil sand The results of the study are given as dimensionless production history plots which may be used to predict the performance of the field they represent. INTRODUCTION Oil fields producing under natural water drive can be classified into two major groups: (1) an "edge-water drive" reservoir group in which the water is encroaching from the reservoir periphery, and (2) the group of reservoirs in which the oil-sand is entirely underlain by an aquifer. Reservoirs in the second group are further subclassified as "bottom-water drive" reservoirs and "thin-oil-column" reservoirs. The latter reservoirs are characterized by their relatively equal oil- and water-sand thicknesses and by having both the oil and water zone relatively thin. When oil is produced from a water-drive reservoir by a partially penetrating well, water breaks through sooner or later before all of the displace-able oil is recovered. Many analyses of this general situation have been made with varying degrees of realism in their approaches, both theoretical and experimental5.6 in nature. Pertaining to the scaled laboratory model studies of natural water drives using porous media, detailed investigations have been made by Henley, et al.7 on bottom-water drive and by Caudle8 on edge-water drive reservoirs. No laboratory model studies, however, have been made to investigate the performance characteristics of thin-oil-column reservoirs. This paper presents the results of a study on scaled models of thin-oil-column reservoirs, operated under varying conditions corresponding to the actual field practices. SCALING PARAMETERS The object of scaling is to produce a one-to-one relationship between physical and dynamic parameters of the model -and prototype. The most comprehensive treatment of scaling techniques for oil reservoirs is given by Geertsma, et a1.,9 which covers two methods for arriving at dimensionless groups for scaling. Table 1 lists the scaling parameters suitable for creating kinematic and dynamic similarities between the model and the prototype in the variables considered for the thin-oil-column reservoirs. In order to achieve similarity it is essential that the dimensionless groups listed in Table 1 have equal values in the model and the protorype simulated. Since it has been established that the role of interfacial forces is neglible in gross fluid movement in a reservoir no attempt was made to scale capillary forces- Although there are reports describing Scaling criteria for these forces,10,ll consideration of the necessary but restrictive conditions for

Jan 1, 1970

By Louis V. Bender, R. E. H. Pomeroy, David H. Browne

E. P. Mathewson, Anaconda, Mont.—After hearing about the success of D. H. Browne with his furnaces, we in Anaconda decided we might venture into the field of pulverized coal for reverberatory smelting. We sent a delegation of investigators to see Mr. Browne and his work, and they returned, filled with enthusiasm, and said they would recommend it strongly.. We thereupon asked for an appropriation, and after some delay obtained the same and fitted up one furnace to use pulverized coal. We copied Mr. Browne's practice and his selection of machinery for drying and pulverizing coal; and we also copied the burner he used, which was a standard article on the market. We got an expert coal-dust machinery man to design our plant, and were very glad we did so as we avoided some of the unpleasantness that had been experienced at other plants through fires and minor explosions. I want to say, before describing our apparatus a little in detail, that we were quite familiar with the work of Mr. SÖrensen, the pioneer in the use of pulverized coal for copper smelting. Our attention had been called to it by Mr. Klepetko early in the game. And afterward we were familiar with the work done at Cananea by Mr. Shelby. We sent an expert to investigate the question 10 years ago. He examined the work of Mr. SÖrensen; and then went to the cement men and examined their work, and reported at great length that coal dust was the ideal fuel for them, as they took the ash from the coal and sold it as cement. He reported that coal-dust firing could not be made economical in reverberatory copper smelting, and his reasons were that a blanket of nonconducting material would cover the charge in a short time and insufficient heat would reach the charge proper, and we would have floaters over all our furnaces. The flues would be stopped by the dust that did not settle on the charge. We accepted that until our Irish friend got busy and showed us how to do it. Then we built a furnace which we thought was a slight improvement over Mr. Browne's. We put railroad tracks over our furnaces to draw the charge to the furnace. We had

Jan 1, 1915

By N. Standish

Heat transfer coefficients have been measured in beds of various packings irrigated with mercury and molten fusible alloy countercurrent to hot gases. The measured coefficients for both systems were found to increase with gas velocities and liquid rates. Correlations were determined which show this dependence and also indicate that heat transfer in these systems is influenced by the liquid flow characteristics and the thermal conductivity of the gas and the solid packings. A heat transfer model has beer2 proposed which explains the various features of the experimental results. On the basis of this study, which gives an insight into the heat exchange in the melting zone of the blast furnace, it was concluded that by comparison with the furnace stack heat transfer coefficients are about 1.5 times higher in the melting zone. EACH year large tonnages of metal are produced in operations which, in part, involve liquid metal irrigation of "packings" countercurrent to hot gases. The melting zone in blast furnaces and in cupolas is a good example of packings irrigated with a liquid melt countercurrent to gases. In all instances of this kind large amounts of heat are exchanged and it is desirable to have some knowledge of heat transfer phenomena involved in these systems. So far the most common method of analyzing furnace efficiencies, fuel requirements, and the general thermal state of the furnace has been through the use of heat balances. As heat balances are essentially statements of the first law of thermodynamics they give no real indication of the factors which govern heat transfer between phases in the various zones of blast furnaces. Hence, rational improvement in production efficiency and the development of theoretical models is only possible if the heat transfer characteristics are known at every stage of the process and related to the important variables involved. This has been generally recognized for some time but it was only recently that Kitaev et al.' have produced a comprehensive treatment of heat transfer in solid-gas countercurrent systems such as the blast furnace stack and the packed bed regenerator. Using their treatment it is now possible to predict the effect of particle size, thermal conductivity, bed porosity, and the flow rates of both the gas and the solid material on the heat transfer in the blast furnace stack. However, the stack of a blast furnace is only one part of an integral unit for which the heat transfer analysis cannot be complete without also considering the heat exchange in the melting zone. The complexity of heat transfer processes in this region of the furnace has so far escaped quantitative description. Yet, the melting zone accounts for a greater amount of heat exchange than all the other zones of the furnace put together. Moreover, if the reduction of oxides in the melting zone proceeds in part in the liquid state the importance of heat transfer on furnace productivity and on the metal and slag temperatures is obvious. THEORY Heat transfer for two-phase flow in packed beds is a complex problem involving a number of heat exchange paths for which interphase areas are not known with any degree of certainty. Analytical solution is, therefore, difficult. This difficulty is emphasized by noting that Rabinovich~ and Luck have only recently solved the steady-state heat transfer for simplified two-phase heat exchangers of known area. However, useful progress can be made for the system considered by making a not unreasonable assumption that the usual heat transfer considerations apply and restricting treatment to the steady state. For these conditions the rate of heat transfer dq in a height dz of a packed bed of unit area is: dq = UaATdz [I.] Integration of Eq. [I] then gives the total heat transferred: assuming both U, the overall heat transfer coefficient, and a, the interphase area, to be independent of bed height. Since a, in these systems, is unknown it is convenient to combine this term with U. The group U, then represents the overall heat transfer coefficient on a volumetric basis. If AT is linear with q, then for a bed of unit volume Eq. [Z] can be integrated to give: is the log mean of terminal temperature differences. From Eq. [3] U, can be readily calculated as q and {AT)im are experimentally obtained quantities, but a difficulty arises in interpreting its meaning. Two approaches are possible depending on whether the effect of packing in the transfer of heat is neglected or not. If the packing is thermally decoupled then the resistance concept gives the relationship: which states that the overall resistance is the sum of the gas phase and the liquid phase resistances (assuming areas are equal throughout). Because the resistance to heat transfer in liquid metals is negligible by comparison with that of the gas,4 Eq. [4] can be simplified, i.e.:

Jan 1, 1969

By F. Forscher

Pronounced porosity, decreasing with distance from the fracture surface, is found in the necked region of tensile specimens tested at room temperature or liquid nitrogen temperature. A hydrogen solution treatment followed by a quench prevents pore formation in tests at —196°C, but has little effect on tests made at room temperature. Reduction of area values at —196°C are strikingly improved by the same treatment, but show no improvement in room temperature tests. The experimental results support the hypothesis that strain-induced porosity results with hydride initially present or, in material containing less than 50 ppm H, with hydride precipitated by strain aging. ZIRCONIUM'S advent as an engineering material in nuclear reactor construction has brought forth many investigations concerned with the properties of this metal and its alloys. Some attention has been given to the ductility of the metal.1, 2 Particularly, the effect of hydrogen on the impact strength was noted," indicating a pronounced dependence of ductility on the hydrogen content and its distribution in the metal. Micro graphic:' and X-ray diffraction studies' have shown that a precipitated hydride phase causes embrittlement in zirconium,' which implies a distinctly different mechanism from that causing hydrogen embrittlement in steels."-' In the latter case, it is assumed that atomic hydrogen diffuses to rifts, where it forms molecular hydrogen under such internal pressures that it causes the rifts to enlarge, leading to fracture. Thermo-dynamic studies of the Zr-H system8, 9 also indicate that the internal pressure of molecular hydrogen would be too low to cause any damage to the zirconium at room temperature, and the formation of a zirconium hydride (d phase) is favored." It is noteworthy that this phase has a face-centered-cubic structure and nearly 18 pet larger molar volume than close-packed-hexagonal a-zlrconlum' Other features of the ductility of zirconium are the absence of a typical cup-cone failure upon tensile testing, a pronounced strain-induced porosity in the necked region of a tensile bar, Fig 1, and the associated spongy appearance of the fracture surface A tremendous improvement in ductility at liquid nitrogen temperature can be observed following a heat treatment that retains the commonly present quan- tities (10 to 50 ppm) of hydrogen in solution. Such tests show a typical cup-cone failure and the absence of strain-induced porosity, Fig. 2. The present paper reports results of an investigation into the causes of strain-induced porosity in zirconium. Room temperature tensile fractures of mild steel, aluminum, and titanium have also been examined for strain-induced porosity. In each case porosity could be detected, but the amount was orders of magnitude less than was found in zirconium. Of the three metals, titanium showed the strongest effect. Material, Specimens, and Preparation The greater part of this investigation was done on Westinghouse crystal bar zirconium, are-melted, forged, and hot-rolled. Chemical analyses of the hot-rolled plates are given in Table I, along with those of the Foote crystal bar zirconium used in this work. The specimens were machined from the hot-rolled plate (1550°F) of 1/2 in. thickness and subsequently heat-treated according to one of the treatments shown in Table IS. All specimens were machined round, the longitudinal axis in the rolling direction, with a gage

Jan 1, 1957

By Thomas T. Read

THE official title of our topic for today is "Resources of Metals and Other Strategic Minerals," but in accepting the invitation to open this discussion I claimed the privilege of being allowed to talk about problems other than resources for the two reasons that a great deal has already been said about resources and because we can never discuss them with the degree of certainty that an engineer likes. Resources are uncertain for many, reasons. One is that we do not know what is in the earth. It is four thousand miles to its center and although oil wells 1 ½ miles deep are becoming common and engineers are now talking of drilling holes 2 miles deep, even when they do they will have advanced only one two-thousandth part of the total distance. Only a relatively few mines are over a mile deep as yet. We know certainly that it is comparatively expensive to work at such great depth, but it would be a very foolish man who would assert it will be' impossible, one or two hundred years from now, for engineers to obtain from great depths mineral supplies that are now being obtained at or near the surface. As long as- I can remember I have been hearing that our petroleum resources were in imminent danger of speedy exhaustion, and yet the yearly output is now of the same order of magnitude as the total resources were once estimated, with ' the cry of over-production the loudest it has ever been. Tapping progressively deeper and deeper sources of supply, has produced this result. Even in the thin layer that we are now working much-exploration still remains to be done. .

Jan 1, 1929

By E. T. Turkdogan, P. Grieveson, J. F. Beisler

Jan 1, 1963