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By Clair Upthegrove, E. S. Rowland

The widespread interest in the alloys of beryllium with copper is due principally to the fact that certain compositions show very favorable precipitation-hardening characteristics and are, in fact, the stronges nonferrous alloys known at the present time. Investigations have been conducted by Masing and Dahl and others on the physical characteristics of ternary beryllium alloys, in an attempt to produce precipitation hardening effects with a smaller amount of beryllium than that required in the binary copper-beryllium alloys (2.0 to 2.5 per cent Be). The results of these investigations show that ternary alloys of beryllium with Cu-Sn, Cu-A1 and Cu-Zn, among others, exhibit promising improrcmc~nts in physical properties after precipitation-hardening treatment and, while the increases in properties obtained are not as high as those reahzed from the binary copper-beryllium alloys, excellent properties arc obtaincd with beryllium contents averagirlg about one-half the amount reqnired in the binary alloys. This paper presents the results of an investigation of the equilibriun relations of certain alloys containing copper, tin and beryllium. The alpha-phase boundary of the ternary system is given for alloys containing from 0 to 1 per cent beryllium. The equilibrium conditions beyond the alpha-phase boundary are presented for alloys containing up to 32 per cent tin and 1 per cent beryllium. The data were collected by means of quenching experiments, microscopic examination and thermal analysis The results of some powder-method X-ray determiniations on the alloys, conducted by Mr. William Mikulas and Prof. Lars Thomassen at the University of Michigan, are used as evidence in this paper. The con

Jan 1, 1935

By Harry Seltz, J. C. DeHaven

InteRmetallic compounds are formed in many binary metal systems. Some compounds are stable to their melting points, and others decompose at lower transition temperatures. Even those of the first class are dissociated in the liquid state, as indicated by the continuous form of their solubility curves at their melting points1. While the lattice structures of some of these compounds have been determined, their thermodynamic properties have not been investigated. In this paper is described the determination of the free energy and heat of formation of the compound CdSb, which is of the first class mentioned above, melting congruently at 455' C. This compound shows a rhombic structure, and the lengths of the edges of the elementary cell containing four molecules are: a = 6.52, b = 8.60, c = 4.16 A.' There are three possible methods of determining the free energy of formation of a compound of this type. The first method, applying the third law of thermodynamics, requires the measurement of its heat capacity preferably to liquid hydrogen temperatures, and a calorimetric determination of its heat of formation. The second method involves the study of the equilibrium of the compound in some gas reaction, such as: CdSb + CO² = CdO + CO + Sb From the known free energies of formation of CdO, CO² and CO the free energy of formation of CdSb could be calculated. The third method measures the electromotive force of a galvanic cell in which the cell reaction is the reversible formation of the compound from the elements. The first method is generally applicable, but requires elaborate experimental equipment. The second method can not be used for compounds melting at low temperatures, owing to the difficulty in establishing equilibrium. The electromotive force method, therefore, seemed to offer

Jan 1, 1935

By C. S. Smith, E. W. Palmer

For several years an investigation has been in progress in the research laboratory of The American Brass Co. to determine the thermal and electrical conductivities of most copper alloys of commercial importance and several of scientific interest. This paper contains such data on the binary alloys of copper with silicon, aluminum, manganese and nickel, and on a large number of ternary or more complex alloys. Some interesting general relationships between the thermal and electrical conductivities for all copper alloys at all temperatures are pointed out. The data for the copper-zinc, copper-phosphorus and copper-tin binary systems have already been published1,2 † except for the electrical conductivity at 200" C., which is given in the appendix of this paper. Literature on Thermal Conductivity of Copper Alloys The papers referred to above contained a summary of the figures available in 1929 for the thermal conductivity of copper alloys. There is given in Table 1 herewith a selection of the data that have appeared since that time. The measurements of Hanson and Rogers3 are particularly interesting since they cover a series of alloys in the alpha solid solution range and show the effect of heat-treatment. Their alloys were tested as annealed castings, and are not therefore directly comparable to the worked alloys measured in the present investigation, although the difference is small. Bailey's determinations4 were carried out on the alloys used by Lees6 in 1906, and extend his results to higher temperatures. It is most unfortunate that the alloys were not analyzed, for the approximate compositions given are hardly sufficient identification of the material. It is equally to be regretted that neither Hanson and Rogers nor Bailey give data for the electrical conductivities of their samples. Sager6, using the heat-wave method of King, determined the thermal conductivity of copper, nickel and four alloys of the two metals. His results are included in Table 1.

Jan 1, 1935

By L.W. Eastwood, Arthur E. Bousu, C. T. Eddy

The recrystallization and grain-growth phenomena of cold-worked metals have considerable industrial importance because of their role in the fabrication of metals. For this reason, and because of the general academic interest in the subject, these processes have received considerable attention since the time of J. E. Stead's paper1 on The Crystalline Structure of Iron and Steel. There are considerable differences of opinion regarding the theory of recrystallization and grain growth and also differences in the observation of the modus operandi of the processes themselves. The value of many of the existing quantitative data on grain growth is decreased by the failure to distinguish between the grain sizes just after complete recrystallization and those resulting from coalescence. For this reason also, the value of the diagrams of stable grain sizes, like those produced by Bass and Glocker2 and Czochralski3, is lessened in so far as an interpretation of the facts of recrystallization is concerned. It is hoped that the data presentcd in this paper will help to clarify and to simplify the facts relating to recrystallization, and at the same time will show that some of the present-day conceptions are untenable. A paper on the theory of recrystallization, with additional data, will be completed in the near future by the writers. Since the literature on the subject has been adequately and frequently reviewed, the only referenccs to it in this paper will be those necessary in the discussion of the data presented.

Jan 1, 1935

By W. A. Mudge, Paul D. Merica

One of the most prominent features of our present-day industrial development is the ever-increasing demand put upon materials of construction. Engineering ingenuity, within the past 25 years, has been unusually active, and in some fields at least engineers frankly say that engineering design has progressed as far as the limitations imposed by the properties of the present materials of construction will permit. Consequently, they are today demanding improvement in their working materials and seeking new ones, through the aid of which the present limitations of design may be overcome. The activity of this search is evident in all fields, but it is particularly so in that of structural materials required to be resistant to corrosion. The corrosion resistance of metals and alloys is never absolute and all-inclusive; a particular alloy will withstand some corrosive conditions well and fail utterly under others. Furthermore, other properties, physical and mechanical, required in conjunction with corrosion resistance vary considerably for different commercial applications. One wants a soft, ductile sheet metal resistant to atmospheric corrosion; another, a high-strength alloy resistant to sulfuric acid. The last decade has witnessed active and definite progress in the development of high-strength, corrosion-resisting alloys. In June, 1924, a symposium by the American Society for Testing Materials, on Corrosion-resistant, Heat-resistant and Electrical-resistance Alloys, disclosed no less than 60 commercial alloys the properties of which were described as being suitable for industrial service where corrosion resistance was a feature. Today the number of these alloys has been doubled, at least. In addition, economy in design and construction through decreased weight has given considerable impetus to the improvement of alloys of which the mechanical propprties may be improved by heat-treatment.

Jan 1, 1935

By T. E. Kihlgren, N. B. Pilling, E. M. Wise

Systematic data are presented on the relation of composition of nickel silvers to color, tarnish resistance, hardness and liquidus temperatures, for alloys containing up to 30 per cent nickel and 50 per cent zinc, further modified at certain nickel and zinc contents by 0 to 8 per cent of tin and 0 to 10 per cent of lead. Attention has also been directed, using a still more limited range of alloys, toward a study of tensile properties and such casting properties and characteristics as fluidity, shrinkage and pressure tightness. In some of these, rather broad ranges of composition are dealt with; in others, it has been expedient to focus attention on the Federal Specification 20 per cent nickel silver casting alloy, WWP-541. Introduction The demand for an alloy essentially white in color, which could be cast and worked by simple methods and which possessed strength and corrosion-resisting properties superior to the usual brasses, led to the discovery and early use of cupronickel alloys containing zinc, and sometimes tin, lead and other metals. This type of alloy was generally known as 'German silver until the war, when the term "Nickel Silver" became generally accepted. The element principally responsible for the white color of the alloy and for its strength and corrosion resistance is nickel, which may constitute from 8 to 30 per cent of the alloy. The functions of the other elements will be described later. The manifold uses of nickel silver are largely due to its color, corrosion resistance, ease of casting, fabrication, joining and rather moderate cost. In many instances the alloy is finished by grinding and polishing while in others it may be finished with a silver or nickel plus chromium plate. Electroplates applied to a nickel silver base behave more satisfactorily than those applied to the softer and less resistant alloys, and owing to the white color of the underlying metal the article will retain a pleasing appearance despite local failures of the plating.

Jan 1, 1935

By J. T. Eash, E. M. Wise

Platinum and palladium are the most generally useful, most ductile and least rare members of the platinum family. They have many important applications in the pure state but for other applications it is frequently desirable to harden them and otherwise modify their properties by alloying small amounts of the other platinum group metals with them. These alloys are frequently required to withstand very drastic forming operations and to possess certain mechanical properties to fulfill specific requirements. For these reasons a knowledge of the tensile properties and annealing characteristics of pure platinum and palladium as well as their more useful commercial alloys is important to the user and the fabricator. The present work was undertaken to fill this need. Rather brief (5 min.) annealing treatments were employed to render the data of maximum practical value and all tests were conducted upon 0.050-in. dia. wire, initially reduced 50 per cent in area by cold drawing, for the same reason. Conclusions 1. Pure (thermocouple grade) platinum reduced 50 per. cent by cold drawing exhibits the following tensile properties: ultimate tensile strength, 36,000 lb. per sq. in.; proportional limit, 27,000 lb. per sq. in.; elongation, 2.5 per cent in 2 in.; reduction in area, 95 per cent. When fully annealed by treatment at 1100°C. its properties are: ultimate tensile strength, 20,700 lb. per sq. in.; elongation, 30 per cent in 2 in.; reduction in area, 93 per cent. 2. The addition of alloying elements in moderate amounts markedly increases the strength and annealing temperature without much detriment to the ductility. The behavior and properties of variously hardened platinum alloys are considered in some detail. The behavior of a 20 per cent iridium

Jan 1, 1935

By Thomas A. Wright

No symposium on die-casting could be complete without consideration of the methods of formula and impurity control. No corisideration of control would be complete without discussion of that new tool of the analytical chemist and inspector, the quartz spectrograph. Just as there is an increased appreciation of the possible applications of the die-casting process and of die castings, so too is there, slowly but surely, of the spectrograph. At present the role of the instrument might well be compared with that of brass or magnesium die castings. Neither is as widely understood or known as they will be. Product specifications are increasing and are getting more explicit and often more rigid. The designer, metallurgist and production engineer or superintendent will be forced to depend more and more on the chemical laboratory. Sampling, as well as analyses, testing and inspection problems will grow. The chemical laboratory must meet its increased responsibility and use of the spectrograph will become more common. Advantages of increased precision, greater speed, lessened labor and often lower costs cannot be ignored. It will be the purpose of this paper in part to outline the respective fields of chemical and spectrographic analyses and to indicate where one may overlap the other and in part to indicate certain possible sources of contamination of zinc-base die-cast alloys in particular. Composition Aluminum.-Aluminum die die castings are expected to conform to the specifications of the Amcrican Society for Testing Materialslt and the Society of Automotive Engineers2. The A.S.T.M. has recognized seven aluminum alloys in Tentative Specification B85-33-T. TWO are straight silicon and the remainder are of the copper-silicon type of which alloys VIII and IX have in addition respectively 2 and 4 per cent of nickel, but unlike the others are not covered by S.A.E. as well. All seven call for rigid control of certain impurities. With the exception of alloy XII,

Jan 1, 1935

By John R. Freeman

This paper relates entirely to the casting of brass under fluid pressure in steel dies. Die castings of metals and alloys of low melting point have been available for many years but the development of brass die castings has been relatively recent, occurring within the past five years. The successful developnlent of brass die castings has resulted from the availability of alloy steels that would give satisfactory life as dies and the development of suitablc die-casting machines. The melting point of copper is 1084" C. (1983" F.) and of a high brass about 900" C. (1652" F.), as compared to 327.5" C. (621.5" F.) for lead, 419.4' C. (786.7" F.) for zinc and 658.7" C. (1217.7" F.) for aluminum, temperatures that are indicative of the casting temperatures required for the various types of alloys, of which the melting points are somewhat lower than those of the pure metals. Type of Die-casting Machine In the well-known plunger and gooseneck types of die-casting machines used for casting the alloys of relatively lower melting point, much of the working mechanism is immersed in the molten alloy. For alloys having the relatively high melting point of brass, this obviously is impossible. Machines with a separate melting chamber are essential. Two rather distinct types are in extensive use at the present time, the Pack and Polak machines, the former designed by Charles Pack and developed at the American Brass Co., the latter developed by Joseph Polak, of Prague, Czeclioslovakia. The principles of operation of these machines have been described in articles by Pack1,2,3 and by Sieg.4

Jan 1, 1935

By W. C. Lilliendahl, H. W. Highriter

The method developed and used in this laboratory for the production of metallic uranium of such purity that it is ductile and can be cold-worked to fine wire or thin sheet by rolling has already been described1. It consists, briefly, in the electrolysis of potassium uranous fluoride (KUF5) in a molten bath composed of equal parts of sodium and calcium chlorides. The bath is contained in a graphite crucible, electrically heated to about 775° C., the crucible serving as the anode for electrolysis. The uranium deposits in finely divided form mixed with salts upon a molybdenum cathode suspended axially in the crucible. Upon completion of the electrolysis the cathode is removed and cooled, the deposit broken and leached to remove salts. The metal powder is washed with water and dilute acetic acid and dried in vacuo to reduce oxidation. Suitable amounts are then prcssed into pellets and heated in vacuo by high-frequency induction, using a thoria crucible. The uranium melts and flows away from the pellet, leaving a shell, which is largely oxide. In general, this method produced a satisfactory metal, although at times tile uranium was not ductile. The investigations recorded here were made to find the cause of this embrittlement. It was known that the metal generally contained carbon, derived from disintegration of the graphitc crucible in which electrolysis is conducted, in amounts dependent upon the thoroughness of washing the metal powder. Accordingly, analyses of several samples, both ductile and brittle, were made by combustion and absorption of CO² in Ascarite, using air instead of oxygen to reduce the temperaturc and rate of oxidation. Several of these metals were made with special precautions to reduce carbon content. The results show no relationship between ductility and carbon content in the range investigated (Table 1). Microscopic examination of ductile and brittle metals disclosed the presence in the latter of an intergranular constituent, harder than the matrix and less easily oxidizable, which was absent from the ductile material. Rough estimates of the volume of the hard constituent

Jan 1, 1935

By R. K. Hopkins

For a great many years fusion welding has been used in and around petroleum refineries, but it is only within six or seven years that the more important pressure vessels have been constructed by this process, because before that time the properties of fusion welds would not withstand such rigorous service. Since the adoption of fusion welding for the construction of this equipment, the refiner has required pressure vessels suitable for operation over a very wide range of conditions. On the one hand, vessels must operate at extremely high temperatures, in the range of 950" to 1000° F., and on the other vessels must be suitable for operation at sub-zero temperatures down as low as —75" F. Also, vessels are required suitable for operation at pressures upwards of 1000 lb. per sq. in., and as low as a 29-in. vacuum. In addition, vessels are required to withstand the attack of very corrosive mediums. It has been a rather difficult task for the fabricator to meet all of these requirements, but as a result of the extensive research carried on by steel manufacturers and several fabricators of class I vessels, practically all of these demands have been met. In order to meet the refiners' requirements for this wide range of conditions, the fabricator has worked closely with the metallurgist. This has enabled him to choose the proper base metal for each service condition, but it has been the fabricator's problem to develop a welding rod and welding technique, as well as a heat-treatment, that would produce in the welded vessel characteristics in and around the weld comparable to those in the base metal. Where corrosion is not a serious problem, and where the operating temperatures are not too high, ordinary carbon steel has served very well. But, when corrosion is serious, and/or when the temperatures are either very high or very low, it is necessary to use some form of alloy steel to give satisfactory service. A great deal of credit is due to the members of the Boiler Code Committee and also to the members of the Joint A.P.I.-A.S.M.E. Committee, who have formulated codes that insure the safety of the

Jan 1, 1935

By Albert G. Zima

According to recently puhlished statistics, it is predicted that as much oil must be produced during the next 16 years as has been produced during the past 75, in order to satisfy the high rate of consumption of petroleum products. During 1934, over 17,000 oil wells were completed in the United States, and it is expected that over 20,000 additional wells will be drilled during the current year. Were it not for the remarkable progress made during recent years in the improvement of drilling technique and in the development of equipment used in the production phase of the oil industry, it is doubtful whether sufficient oil could be produced to meet present requirements. A few years ago, wells seldom were deeper than 3500 to 4000 ft., owing to the limitations of the drilling methods and equipment employed. Today, however, through the application of scientific drilling methods and the adaptation of modern equipment and improved materials, many wells range from 6000 to 8000 ft. in depth, and a few recent completions exceed 10,000 feet. Drill Tools Modern rotary drilling tools are the product of ingenious design and careful selection and adaptation of materials used in their construction. They must withstand terrific abrasion and, because of their compactness, must be designed to resist exceedingly high unit stresses. In bits, core drills and reamers, the bodies are made of either forged or cast alloy steels, heat-treated to develop a combination of high strength and toughness. To provide sufficient strength to the threaded portions and to protect the threads from distortion or damage, the box or pin sections of the tools are hardened to approximately 310 to 330 Brine11 hardness number. Drill and reamer cutters are generally of the movable type; i.e., serrated cones, cylinders or disks, which can readily be replaced when

Jan 1, 1935

Jan 1, 1935

By Frank G. Norris

Slag control is adjustment of the composition of the slag, especially with respect to the FeO content. The theoretical method of slag control would be to charge a mixture of pig iron and scrap of given composition into the furnace, to melt always at the same carbon, and, after a uniform ore addition, to tap with a constant slag composition. Such conditions are not even approximated. Both scrap and pig iron are of variable, and, in many cases, unknown composition. The charge is oxidized to a variable extent during melting. The result is that the FeO content of the slag, and consequently of the metal at tap, varies over a wide range. In order to make a nearly uniform product, this variation must be compensated for in some way. One way is to adapt the ladle deoxidation to the requirements of the metal. The other is to control the slag. In a general sense slag control may be considered as a method of compensating for variations in the composition of the charge and in oxidation during melting. The method of slag control for low-carbon steel was developed by Dr. Herty at our Butler plant3. Use of this method enables the furnace operator to tap heats at a more nearly constant FeO content and, therefore, to use a more nearly uniform deoxidation practice. The desired FeO and the accompanying deoxidation will depend on the application of the product. This statement implies that 0.10 carbon steel finished with a 15 FeO slag may be essentially different from a 0.10 carbon steel finished with a 30 FeO slag. In making low-carbon steel, the desired carbon places a lower limit on the FeO content of the slag, because the slag must be sufficiently oxidizing for proper carbon elimination. With this degree of oxidation, the phosphorus specification is met without difficulty, and there is little danger of phosphorus reversion. Thus a limiting factor in high-carbon heats is of slight importance in low-carbon heats. For heats of 0.05 to 0.07 per cent carbon, the FeO content of the slag may be controlled at

Jan 1, 1935

R. H. Sweetser.—Mr. Reinartz spoke of slag containing 18 per cent FeO. I think he expressed the iron as oxide. I should like to ask at what point, in iron contents, it is usual practice to quit sending that open-hearth slag to the blast furnace? L. F. Reinartz.—NO problem is involved in disposing of open-hearth slag to our blast furnaces because, on account of the grades of iron and steel made by our company, the iron oxide in the slag is sufficiently high to make it very acceptable to the blast-furnace operator. I have been told that if the total iron oxide in the slag is under 18 to 20 per cent, it is not economical to use such slag in a blast furnace. J. T. Mackenzie,* Birmingham, A1a.—Mr. Reinartz mentioned sulfate in the limestone. I wonder if he did not use the wrong word. We always have assumed that the sulfate sulfur is practically harmless. Most limestone carries some pyrite (sulfide sulfur) which we thought was what gave the sulfur pick-up. L. F. Reinartz.—I have had no experience, personally, in the use of limestone high in sulfates. I have been told, on several occasions, by other open-hearth men, that the sulfates will be reduced and increase the sulfur content of the metal. We have never found any pyrite in our limestone. A. Hayes,† Middletown, Ohio.—I should think that sulfates would be readily reducible to sulfites, and possibly to sulfides at various distances through the slag layer, from the top down to the interface between the bath and the slag, because reducing conditions are certainly sufficiently strong next to the bath in the slag to reduce sulfates to sulfides. A. L. Feild,‡ Baltimore, Md.—What is Mr. Reinartz's theory as to the effect of silica in the slag on the iron oxide content of the metal? L. F. Reinartz.—I have no particular theory as to the effect of silica in the slag on the iron oxide content of the metal. I know from practical experience that it does have an influence on reduction of iron oxide in the metal. We know that if the silicon content of the charge, and, therefore, the silica of the slag is increased, the iron oxide in the slag will be decreased. Based on Dr. Herty's work, we assume that the iron oxide is correspondingly decreased in the metal. C. H. Herty, JR.,§ Bethlehem, Pa.—In the theory of iron oxide control, we have tackled the matter from the physical standpoint, rather than the chemical standpoint or from the slag itself, and we worked on the basis that the change in iron oxide content in a slag—that is, whether the slag increases or decreases in iron oxide—is due to the simple fact that if you put more iron oxide into the slag from the gas than you put oxygen from the slag into the metal, the slag must increase in iron oxide;

Jan 1, 1935

By W. J. Reagan

All of the material described in the following paper is within the following specifications: carbon, 0.50 to 0.85 per cent; phosphorus and sulfur, 0.04 per cent max.; manganese, 0.60 to 0.85 per cent; silicon, 0.20 to 0.30 per cent. Steels with much lower carbon contents can be handled in exactly the same manner. One of the first things necessary to basic open-hearth slag control is uniformity of charge, particularly as to the silicon content and the percentage of lime charged. Our past work has shown that the silicon content of the charge is more important than the carbon content in determining the carbon at which a heat will melt. We have found that by keeping the silicon content of the charge about 0.60 to 0.65 per cent, and with a lime charge of about 7 per cent (limestone equivalent), our heats melt sufficiently high in carbon to allow a moderate feed of ore and the slag will be of low iron oxide content. In making a heat of 0.75 carbon steel we endeavor to have the heat melt at about 1.20 per cent carbon. The iron oxide content of the finishing slag depends upon the final phosphorus desired; for a given ratio of lime-silica in the slag, the lower the phosphorus desired in the final steel, the higher the iron oxide content of the finishing slag must be. By reducing the lime charge to a minimum, the heats melt faster, and by keeping the silicon content at the desired figure the heats melt with a high SiO2 slag, which has been shown in previous work to give a low iron oxide slag. In most of our work, using a 180,000-lb. charge and with basic pig containing about 1.20 per cent silicon, we use a lime charge of 8500 lb. of limestone and 2000 lb. of burnt lime. The pig charge is about 48 per cent of cold pig, and the charge contains a large percentage of works scrap. This causes a heat to melt with about 1.20 to 1.30 per cent carbon, for a heat that will finish about 0.75 per cent carbon. This gives a heat that will need a feed of about 2000 lb. of ore, and also a slag with an FeO content of about 4 to 5 per cent at melting. The additional FeO obtained from the ore addition will bring the FeO in the slag at tapping to about 6 to 7 per cent. It is necessary to carry quite a fluid slag to prevent pickup of FeO, as a too heavy slag causes FeO to build up in it, giving a finishing slag with a greater FeO than is desired. By adjusting the lime charge of a basic open-hearth heat, a very sensitive adjustment of the slag may be obtained. The figures in Table 1

Jan 1, 1935

By W. R. Hicks, J. E. Pollock, E. Camp

In the oil-refining industry, steel comprises by far the greatest proportion of the materials used in construction work, but with an enormous number of alloy steels and nonferrous alloys available, and a greater knowledge of their properties and corrosion resistance, a substitution first in the "hot spots" and then in locations of moderately severe corrosive conditions will be made as the greater expense can be justified. In new construction work, advantage is taken of the experience already gained and appropriate materials used, whether for high temperatures and pressures demanding additional strength or for corrosive conditions. The locations, however, where equipment in operation constantly requires replacement will soon become evident, as will the necessity for replacement in more resistant materials, if considerable down-time is to be avoided. In what direction and how far to go in the matter of alloys then becomes a question of the highest importance. Obviously, any replacement with more costly material must be justified economically by the promise of longer life, thereby saving both material and installation costs besides the reduction of loss of production. Where the equipment is overcapacity and a regular schedule of cleaning periods is in force, the last item frequently must be ruled out and justification made on the basis of the first two only. Installation of material that will outlast the remainder of the equipment and have no recovery value must also be avoided; this is particularly important in temporary construction or in old equipment that will soon become obsolete. Test Methods Either one of two methods or a combination of both, in the absence of reliable data in similar services, may be adopted to determine to what extent replacement with other, and perhaps more expensive, materials is justified. A unit may be constructed incorporating different metals or alloys so that comparative service may be obtained under the same service conditions; this has been applied in many instances, such as condenser and tank construction, but the opportunities for inspection may be few and

Jan 1, 1935

By A. E. Harnsberger

I is obvious that details such as the physical and chemical properties and methods of heat-treating of the materials mentioned must be omitted in a paper on the subject of materials used in oil-refinery pumps1. Only sufficient identification is given to enable the reader to find additional information from already published data. Also, the subject covers many operating conditions, but only the most important services can be discussed here. To the oil refiner, the pumping equipment is of vital interest. Practically every refinery operation, from the charging of crude oil to a distillation unit to the shipping of refined products, involves some form of pumping machinery. Intermediate refining stages involve a great variety of pumping machinery to carry out successfully the aims of the refinery technologist. Temperatures at which oils are handled vary from — 50" F. to 900" F. Pressure may vary from subatmospheric to 2000 1b. per sq. inch. The selection of the proper materials involves a careful consideration of the conditions under which the particular pump must operate. The four most important considerations are temperature, pressure, corrosion, and abrasion or wear. Consideration of temperature may be divided into three parts: (1) extremely low temperatures of the order of —50" F.; (2) temperatures at atmospheric or slightly above; (3) temperatures from 200" to 900" F. Pressures fall into two groups: (1) pressures reached by ordinary trade pumps of the order of 200 lb. per sq. in., (2) extreme pressure conditions involving pressures as high as 2000 lb. Noncorrosive and corrosive oils can be treated differently. Under the latter falls corrosion in the presence of water, which will occur up to 250" F. The second type of corrosion occurs in high-temperature pumping equipment, with temperatures from 450" to 900" F., largely caused by sulfur compounds. There are also other corrosive conditions met with in refinery operations, particularly in the handling of acids, acid sludges and other specialized processes. These problems, although difficult to

Jan 1, 1935

By R. L. Wilcox, M. L. Fuller

Owing to the nature of the die-casting process, fresllly cast alloys are undoubtedly not at equilibrium from the standpoint of alloy phase relationships. After casting, therefore, they tend to undergo phase changes, with the ultimate effeet of reaching a state of equilibrium at the aging temperature, beyond which no fnrther change takes place. This phase alteration undoubtedly is one of the primary causes of the changes in dimensions and physical properties that zinc-alloy die castings undergo during aging. It is planned to report on this problem in a series of papers of which this is the first. The writers have made a study of commercial zinc die-casting alloys over a period of several years, utilizing the X-ray diffraction technic of determining the phase composition changes in the alloys. Up to the present, two principal phase changes have been observed which are capable of causing dimensional changes: (I) the segregation of secondary constituents from the zinc-base solid solution and (2) the beta aluminum-zinc decomposition. The latter is the subject of the present paper and studies on the former will be reported upon at a future time. Scope of Study In the present investigation a special technic for the study of the beta phase in zinc-alloy die castings has been developed, making possible the determination of the period of existence of the beta phase after casting. The pure beta constituent and its decomposition have been studied in detail. The effect of magnesium and copper on the velocity of the decomposition is reported. The heat of decomposition, the eutectoid temperature arid the accompanying density change have been measured. The density change lias been calculated from data on crystal structure and the result thus obtained has been compared with the actual change.

Jan 1, 1935

By J. J. Bowman, E. H. Dix

A lack of experimental data illustrating the effect of composition, particularly in respect to impurities, on the mechanical properties and corrosion resistance of aluminum-alloy die castings induced the authors and their associates to undertake a limited study of these relations. A number of commercial alloys and several experimental variations of a commercial alloy were used for the investigation. Mechanical property, growth, steam, paraffin, salt spray and atmospheric exposure tests were employed. This paper deals with the more accelerated tests and the results they have produced. It is concluded that a high-silicon alloy with all impurities except iron strictly limited to small amounts will develop an excellent resistance to corrosion and retain satisfactory mechanical properties and casting characteristics. As a direct result of this investigation an alloy of this character with superior corrosion resistance is now available commercially. In general, copper increases the strength and decreases the elongation and corrosion resistance. Tin reduces the mechanical properties and the resistance to corrosion. Iron reduces the elongation and, if excessively high, may adversely affect the tensile strength. Even excessively high iron contents do not affect the corrosion resistance, which is fortunate for the die caster as it is this element that is the most difficult to control. Nickel and zinc in limited amounts do not seem to affect the properties or corrosion resistance of at least the high-silicon alloy. Growth tests have confirmed the previous common belief that dimensional changes under either dry or wet conditions at 100" C. are too small to be of practical importance. Introduction The technical literature contains numerous papers describing die castings, their production, compositions and uses, but nearly all of these

Jan 1, 1935