ss Steels Other Ferr - ACS Publications

Ebonite dentures made from rubber latex compositions. (87) Werkenthin, T. A,, Rubber Age, 59, 173-9, 317-23, 446-50,. 697-702 (1946); 60, 74-8, 197-20...
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INDUSTRIAL A N D E N G I N E E R I N G C H E M I S T R Y

properties of several important classes of plastics and three grades of hard rubber. Wentworth, V. H., Inst. Rubber Ind. Trans., 22, 149-58 (1946). Ebonite dentures made from rubber latex compositions. Werkenthin, T. A , , Rubber A g e , 59, 173-9, 317-23, 446-50, 697-702 (1946); 60, 74-8, 197-202 (1946). Discusses tests used by Bureau of Ships for testing hard rubber and other rubber products. White, W. L., and Schatzel, R. -4., Office of Publication Board, U. S. Dept. Commerce, Washington, D. C. P B 220 (1946). Formulas and manufacturing techniques used in a German plant for lining tanks and making rolls from hard rubber. Zbid., PB 1042 (1945). Description of equipment and methods used in producing rubber-lined steel tanks and molded hard rubber articles in a German plant.

Vol. 40, No.. 10

(90) Willott, W. H., J . Rubber Resezrch, 15, 250-1 (1946): Rubber Chem. Technol., 20,525-6 (1947). Effect of temperature on

cross-breakingstrength and elongation. (91) Wolff, F., German Patent 745,824.

Molded accumulator containers. (92) Young .4ccumulato~ Co., Ltd., Mech. Handling, 32, 674-80 (1948). Illustrated description of stages in manufacture of haid rubber batteries. (93) Yorke, L. E., Spilfogel, C. L., Howell, N. L., Holt, II.,Dowse. J., Bills, E. T., and Spencer, G. D., British Intelligence Objectives Sub-committee, H. M. Stationery Office, London, Final Rept., 767, Item 31, 1946. Accumulator manufacture in Germany. RECEIVED July 31, 1948.

ss Steels

Other Ferr M. H. BROWN AND W. B. DELONG E. I . d u Pont de Nemours & Company, Ine., Wilmington, Del.

R

EVIEW of the literature on stainless steels and other ferrous

alloys for the past year indicates that the results of most of the specialized investigations undertaken to fulfill wartime needs have now been made available. Research in this field csontinues to be very active, however, and important work is currently in progress. Extensive investigations for properly assessing the advantages and limitations of the now commercially available austenitic stainless steel grades containing 0.03y0 maximum carbon are being carried out in several laboratories. Although essentially nothing had appeared in the literature on this subject at the time of preparation of this review, definitive ininrmation should be forthcoming during the next year. Both the 18-8 and 18-8-Mo extra low carbon grades are in limited commercial use. There has been considerable activity in the field of passivity of btainless steels during the past year and important progress has been made toward a better understanding of this phenomeuon. Valuable results have been developed on the effect of heat treatment and modifications in composition on the corrosion resistance and mechanical properties of the conventional austenitic and ferritic stainless steels. Important contributions have also been made in the compilation and correlation of data on the hot gas corrosion resistance and behavior a t high temperatures of the cast heat-resistant alloys. Among the new compositions announced during the year is a wrought stainless alloy of nominal analysis (in per cent by weight) carbon 0.07 maximum, manganese 0.75, silicon 1.0, chromium 20.0, nickel 29.0, molybdenum 2.0, and copper 3.0 minimum. Corrosion resistance appears t o be comparable to cast alloys of similar composition which have gained widespread use, particularly in applications involving the handling of sulfuric acid solutions. Information on the properties of this alloy, including corrosion data, was rex icwrd by Fontana (74). PASSIVITY AND CORROSION RESISTANCE

Important contributions have been made in the study of passivity, oxide films, and related stainless steel corrosion phenomena. Guitton (93-96), who has published several papers dealing with the passivation of the stainless steels, considers that passivity is primarily the result of chemical adsorption of oxygen on the

metal surface. Prior acid corrosion, termed “sensitization,” was reported to accelerate passivation in an oxidizing medium and t o increase its stability toward further corrosion. Uhlig (214, 816) also considers the surface phenomenon of passivity to be one of chemisorption. Iron plated or evaporated over chromium was found to be resistant to nitric acid a t the interface. This is interpreted to mean that intimate contact with chrorniiim alters the reactivity of the surface iron atoms and to providc support for Uhlig’s “clectron configuration” theory. The work of Fontana and Beck (16, 70, 71, 75) has led them to support the hypothesis that a physically adsorbed pas fil~nis responsihle for passivity. Type 301 stainless steel specimens, passivated by exposure to sulfuric acid and then t o air, were found to become active in air-free 10% sulfuric acid o r synthetic sea water after subjection to a vacuum, and again passivc after subsequent exposure to air; this action was completely reversible. By employing a solution of bromine in methanol as a stripping agent, Mahla and Nielsen (139) succeeded in isolating oxide films from austenitic and ferritic stainless steel specimens which had been pickled and exposed to air or to other oxidizing media. Study of the films by means of electron diffraction and microanalytical techniques led to the tentative conclusion that thcir lattice is of the spinel type. Colner (49) reviewed investigations and theories dealing with the passivity of stainless steels and concluded that most of the evidence favored the t,lieory of protection by surface oxide films. The kinetics of the oxidation process of metal surfaces were discussed by Mott (146, 147) and by Gulbransen (97),who enumerated and assessed the importance of eleven fundamental variables. The transition rate theory was applied to the comparison of the oxidation behavior of various metals. Gulbransen, Phelps, and Hickman (98) and Hickman and Gulbransen (101) made an electron diffraction study of the oxide films formed on high temperature oxidation-resistant alloys. No unique oxidation mechanism was shown to exist for Types 301 and 446 stainless steels. The oxides over the complete time-temperature range consisted of chromic oxide or a spinel of unknown composition. Mahla and Sielsen (158) adapted natural oxide films formed on stainless steel surfaces by oxidation in a molten nitrate bath and stripped by means of a bromine-methanol solution to use as sur-

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INDUSTRIAL AND ENGINEERING CHEMISTRY

face replicas for electron microscope studies. The sorption of several gases on specially prepared stainless alloy surfaces at 20°, -78’, and -183” C. at pressure6 up to 0.1 cm. was measured b y Armbruster (9). Dravnieks and McDonald (60) determined the electropotentials of growing halide and oxide layers on several materials by means of a n electrode probe. The oxide o n stainless steel was investigated and was concluded to be a n electron conductor. The austenitic stainless steel alloys w e subject to severe intergranular corrosion in many service environments unless they are properly heat-treated after fabrication or other operations involving exposure t o intermediate temperature ranges, or a r e rendered immune by the addition of “stabilizing” elements, such as columbium or titanium, which fix the carbon in an inert a n d harmless form. An example of “weld decay” is shown in Figure 1, in which the damage done by welding a 0.07% carbon 18-8 steel is illustrated. This specimen was cross-welded; the horizontal weld bead was the last one deposited, and pickled in 10% nitric-2% hydrofluoric acids. It is interesting to note how the intergranular attack parallels the weld beads but is separated from them by a discreet zone of relatively unattacked material. This zone, like the weld metal, was cooled rapidly enough t o prevent loss of its corrosion resistance in the intermediate temperature range. Rosenberg and Darr (176) summarized the results of a n extensive investigation of factors affecting the stabilization of the 18-8 type of stainless steel. The data had been previously available only in a series of progress reports. The study included 18-8 of varying carbon contents (0.025 to 0.113%), 18-8-Cb at low and high carbon levels with columbium-carbon ratios of 7.4 to 11.8, a n d 18-8-Ti at low and high carbon levels with titanium-carbon ratios of 3.9 to 7.9. Specimens were evaluated as cold-rolled and with eleven combinations of annealing (1800” t o 1975” F.) and stabilizing (1600° F.) treatments and lengths of time at temperatures with and without subsequent sensitizing treatments for various times at 840 ’, 1020 ’, and 1200’ F. The specimens were evaluated by means of a boiling aqueous solution containing 5.4% copper sulfate and 15.4% sulfuric acid, by weight, with exposure times from 2 to 14 days, following which the degree of intergranular attack was assessed by several methods. The results indicate that, under the test conditions employed, (1) increase in both columbium-carbon and titanium-carbon ratios had a markedly beneficial effect upon resistance to intergranular corrosion; the ratio required for substantial immunity varied with the initial condition of the steel, and within the ranges studied, was apparently independent of the carbon content; (2) for satisfactory resistance to intergranular attack, stabilizing heat treatments at 1600 O F. appeared unnecessary for 18-8-Cb but highly desirable for 18-8-Ti; (3) with the most favorable heat treatment, substantially complete immunity may be obtained with a minimum ratio of columbium to carbon of 10 and of titanium to carbon of 5. Ratios of 12 and 8, respectively, are considered more foolproof. Schoefer (182) reported the results of a n investigation of the effectiveness of stabilizing agents on cast CF (19-9) type alloys. The boiling 657, nitric acid test was employed for evaluation. Columbium, if present in amounts of eight times the carbon content or above, was found to be generally effective in preventing intergranular attack on specimens “sensitized” at 1200O F. Some improvement in corrosion resistance, especially with lower chromium contents, was observed when a stabilizing heat treatment of 1600’ F. was employed prior t o sensitization. Cast titanium-bearing alloys showed high rates of attack even after such treatment, and were considered unsatisfactory. Specimens of cast 19-9-Mo with columbium additions also showed relatively high corrosion rates in the sensitized condition. Phillips (156) also studied the effectiveness of stabilization in wrought Type 321 Stainless steel by bend tests after 48-hour exposure in a boiling aqueous solution containing 5.470 copper sulfate and

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15.4% sulfuric acid, by weight. An equation was derived for predicting behavior which was correlated with experimental results under the testing conditions employed. Stewart (206) questioned the use of the boiling 657, nitric acid test for evaluating the susceptibility of Type 321 stainless steel to intergranular corrosion. Evidence was cited to indicate t h a t the relatively poor resistance of sensitized Type 321 material to boiling 65% nitric acid is not due to carbide precipitation. Jaskewich and Samarin (112) concluded that columbium showed advantage over titanium as a stabilizing agent for stainless steels. Kirtchik (120) developed a corrosion test involving evaporation of lead bromide solutions to evaluate resistance t o intergranular attack under conditions involving temperatures above 1200 ” F. in the presence of lead halides, as in aircraft supercharger nozzle boxes. Test results indicated Inconel t o be more resistant than Type 347 stainless steel, which was in turn more resistant than Type 316. Plankensteiner (167,158) proposed the use of boiling 0.57, sulfuric acid solution for the detection of susceptibility of stainless steels to intergranular attack. A group of seven valuable papers dealing with the resistance of stainless steels to atmospheric conditions was presented at the 1946 meeting of the American Society for Testing Materials and has since been published (4).The results of stress-corrosion tests in boiling magnesium chloride solutions employing various types of test specimens made from Type 347 stainless steel are described by Springer, Succop, McKinney, and Scheil(Z04). Ericksen cup, circular weld, beam type, and tube-to-header specimens were used and the data obtained compared and discussed. Glikman and Stepanov (82) describe the failure of high-chromium steel bushings on turbine shafts by stress-corrosion cracking. Zappfe and Specht (281) and Zappfe and Haslem (250) studied the effect of alloy composition, heat treatment, cold work, acid composition, temperature, and pickling time on the hydrogen embrittlement of stainless steel wire during cathodic pickling.

Figure 1. Weld Decay in Welded

18-8

The corrosion and maintenance of stainless steel equipment in oil refineries were discussed by Renshaw (169, 170). Speight (198)reviewed the performance of stainless alloys in dairy service. Bergstrom and Lientz (20) described the use of stainlese clad steel in the paper industry. Banks (14) reported that Type 316 stainless steel shows excellent resistance t o flue-gas vapors; Type 304 is said t o be excellent up to a certain point, after which sudden and severe attack occurs. Schrader and DeHaan (183) discussed service experience on stainless steels and other materials at Oak Ridge. Fontana (79) listed corrosion data for Stainless W (a precipitation-hardening steel of the “lean” 18-8 type) in various media. Data on the resistance of stainless alloys to phosphoric acid (64,111,160),wet and dry chlorine (6, W11), sodium chloride (132,

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161,195), nitric acid (196),sulfur dioxide (7, M I ) , andsulfuricacid (48, 134, 168) were included in a series of symposia on corrosionresistant materials. -4 great deal of useful information on the corrosion resistance of the stainless alloys to many media is contained in the Corrosion Handbook (21.5) issued in 1948 by the Electrochemical Society, STRUCTURE A R D MECHANIC4L PROPERTIES

Payson and Savage (153) investigated the conditions required for the formation of sigma phase in Types 302 (18-8),309 (25-12), 310 (25-20), and 311 (20-25) stainless steels. High percentages of chromium, silicon, and nitrogen, low carbon content, and additions of columbium, titanium, and zirconium were found to favor sigma formation after long holding periods a t temperatures between 1100" and 1700" F. Conversion of sigma to austenite requires heating as high as 2250" F., although considerable ductility can be restored by heating at 1900 O to 1950' F. Smith and Bowen (194) reported sigma phase to be formed from ferrite in 18 Cr-8 Ni-3 Mo-1 T i stainless steel during exposure at temperatures from 930" t o 1780" F. I t s presence was found to affect adversely both mechanical properties and corrosion resistance. An instrument called the Forrometer, which enables changes in ferromagnetism to be followed and measured, was developed and eniployed to advantage in the investigation. Kirliby and hlorley (119) studied sigma formation in two 18-8 type steels containing molybdenum and columbium in one case and molybdenum and titanium in the other. Sigina was reported to form rapidly at 1560" F. in both alloys. Kirkby and Morley suggest t h a t sigma forination, like carbide precipitation, may result in local alloy depletion which may decrease corrosion resistance under certain circumstances. The use of x-rav methods for the identification of small amounts of sigma in 25-20 and other stainless alloys was described by Barnett and Troiano (16). Details of metallographic techniques for differentiating between sigma and carbides are given with illustrative photomicrographs by Emmanuel (63). Bloom, Goller, and Mabus ( 2 3 ) studied the cold-work hardening properties of austenitic and ferritic stainless steels by means of a special compression test. I n the austenitic steels, increasing the nickel content consistently decreased cold-work hardening, while the effect of chromium depended upon the nickel content. Carbon increased the tendency for hardening, nitrogen decreased it, and columbium, titanium, and molybdenum showed only a minor effect. Increased Ivork ng temperatures up to 400" F. decreased cold-work hardening of the austenitic alloys greatly but only slightly affected that of the ferritic alloys. The latter in general hardened t o a lesser degree and were less influenced by variations in composition. Post and Eberly (159) investigated the stability of austenit: in a number of chromium-nickel stainless steels by measuring the change in magnetic permeability after cold reduction. An empirical formula mas developed for estimating the nickel content required to make a chromium-nickel stainless steel "substantially stable" (defined as requiring 8070 cold reduction to cause a noticeable change in magnetic properties) ; the formula takes into account the influence of carbon, manganese, and molybdenum. The difference between this theoretical value and the actual nickel content was evaluated as a factor A which was employed as a measure of stability. AlcAdam, Geil, and Cromwell (136) made tensile tests of notched and unnotched 18-8 specimens between room temperature and - 188a C. Plastic deformation was found to cause a phase change and thus harden the alloy. Hobson and Osmond (105) reported the results of research on the ferro-magnetic structure of cold-worked austenitic steels. They proposed the idea of a dispersion of ferrite particles, probably long in relation to their cross section, and of individual volumes of the order of a single domain, in a nonmagnetic matrix of austenite.

Vol. 40, No, 10

HIGH TEMPERATURE CORROSIQU 4YD PROPERTIES

The increasing need for metal parts for operation a t elevated temperatures has fostered considerable work in this field. Extensive work has been done on the "super" alloys in the search for materials for use in the high temperature portions of gas turbines. Because of their high alloy content and the difficulties in preparing, machining, and welding them, these alloys are expensive and largely limited in their application except for gas turbine parts. They are therefore not of general interest in chemical plant construction and are not discussed here. The conventional alloys can be used in the lower temperature areas of gas turbines and also find extensive use in parts and accessories for the continuous heat treatment of steel, high temperature cracking of gases, dehydrogenation units, etc., and considerable work has been carried out in order more adequately to evaluate them for these purposes. &4nextensive program of work on the high temperature properties of alloys has been underwritten a t the Battelle Memorial Institute by the Alloy Casting Institute. The first of this work, published within the past year, has constituted an important contribution to the literature in this field. Gow (86) pointed out t h a t corrosion of the iron-nickel-chromium alloys may consist simply of surface scaling or of subsurface changes such as decarburization, carburization, nitridation, or intergranular attack. Consideration of the behavior of the components of a given alloy cannot be used to predict, except in a very general way, the performance of the alloy under any given gas exposure. Shorttime tests indicate that reducing flue gases containing hydrogen sulfide or carbon monoxide, hydrocarbons, or ammonia are the most dangerous to handle in these alloys. For oxidizing flue gases, increasing the sulfur content from 5 to 100 grains per 100 cubic feet had little effect on the corrosion. Reducing gases, containing 5 grains of sulfur per 100 cubic feet, were less corrosive than oxidizing gases of the same sulfur content for iron-chromiumnickel alloys of 15V0 chromium minimum and covering the whole range of nickel contents tested. When the sulfur content is raised to 100 grams in the reducing gas, hol\ever, the corrosion becomes severe for all alloys with less than leyo chromium and any nickel content. Brasunas, Gow, and Harder (27) presented data on the air oxidation of iron-nickel-chromium alloys a t 1600 to 2200' F. The most beneficial effects of nickel in these alloys was found a t low chromium levels; at 267& chromium, nickel is not csscntial for this type of corrosion resistance, mechanical factors not considered. Two optimum composition ranges wcre found: (1) 287, Cr-20yO Ni and ( 2 ) 16?o Cr-GO% Xi. In the first type, increased carbon contents resulted in more severe corrosion ; this effect was most pronounced a t the higher temperatures. The optimum silicon content was found to be 1 5y0 and acts in part as the equivalent of chromium. Most of these tests were of only 100-hour duration, but 1000-hour spot tests were found to substantiate the trends observed during the shorter intervals. Intermittent heating and cooling tests generally indicate higher corrosion rates due to the loss of scale by flaking. Sicholson and Kwasney (151) worked on the scaling of ironchromium-nickel alloys in sulfur dioxide-, oxygen-, and nitrogenrontaining atmospheres. Tests on a number of materials, primarily lox-alloy steels, showed A.I.S.I. Type 316-Cb (18-8-MoCb) to be a ruitable alloy for use in sulfur dioxide up to 1200" F. Pray, Fink, and Peoples (162) reported that 18-8-Mo is preferred over 18-8for flue gas service. The latter may perform well for a? much a3 18 months before breakdown occurs. Pitting frequently causes failure of 18-8 and aluminum. Stauffer and Kleiber (206) described their work on determination of the oxidation of a number of alloys a t temperatures up to 1000" in air and in combustion gases containing sulfur. -4very ( 1 1 ) published a series of nomographs indicating the degree of oxidation of various grades of alloys in air at lGOO", 1800", and 2000" F. based on the work of Brasunas. H e also

c.

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INDUSTRIAL AND ENGINEERING CHEMISTRY

presented the types of subsurface corrosion experienced in these alloys a t 1800" F. in air and in reducing flue gas, as well as their corrosion in oxidizing and reducing flue gases containing sulfur. McCullough (137) studied the rates of oxidation of Types 304 (18-8) and 410 (12y0 chromium) between 850" and 2200" F. in nitrogen-oxygen mixtures containing from 2 t o 95% oxygen. Chromium was found to be primarily responsible for oxidation resistance and Type 304 was not oxidized as much as Type 410 a t elevated temperatures. Chevenard and Wache (44) observed that the dry oxidation of 197, Cr-lO% Ni steel took place in three steps. After a n initial slow period it increases rapidly to a more steady rate which is dependent upon the oxide scale thickness. Electrolytically polished surfaces were found t,o behave more consistently than mechanically finished surfaces. The oxidation of several metals, including 18-8 up to 300" C., was studied by Campbell and Thomas (40) by the use of a differential manometer for measuring the decrease in pressure of a fixed volume of gas on heating. Kornilov and Shpilrel'man (121) studied the oxidation rates of a series of iron-chromiumaluminum alloys with chromium held constant a t 40% and aluminum over the range 2 to 13%. After oxidation the alloys were reanalyzed chemically and their weight loss and electrical resistivity were measured. I n another paper (129) these authors described work in which a 0.6y0 C-1.7 Si-28 Cr-27 hTi alloy was similarly treated at 2010" and 2190" F. for 750 hours. I n both cases oxidation occurred a t the expense of the elements most easily oxidized. Ihrig (110) reports t h a t for exposures involving both alternate carburization and oxidation at 900" to 1300" F., 287, chromium (Type 446) is the most suitable. These conditions are met in such reactions as the dehydrogenation of butane to butadiene and i t was found t h a t the addition of a small amount of sulfur t o the gas produced just enough sulfidation of the surface of the alloy to inhibit serious carburization and oxidation. Hubbell (106) described carbon pickup that occurs in Types 347 (18-8-Cb) and 321 (18-8-Ti) when used as exhaust manifolds in aircraft engines and t h a t its degree is a function of time, temperature, and the type of fuel used. H e reports that carbide networks around the grains are frequently formed, but t h a t intergranular corrosion does not ensue. Sarkisov (179) described the oxidation resistance of chromium-rich films formed on low-carbon steel by exposure to chromium chloride vapor at 1830" F. for 3 hours. Surface coatings of 30 to 35% chromium 0.078 inch thick were obtained. I n a n alternate heating and cooling test of 1650' F. maximum temperature, i t was found that the oxidation resistance was essentially the same as that of 30% chromium steel. Above 1830' F., the coatings made from chromium and aluminum chloride vapors were more resistant to oxidation. At 1830" F., the rate of increase of weight for the chromium-aluminum coatings was not over 1 gram per square meter per hour. Avery and Willrs (1s) in a comprehensive paper described the properties of the cast H K alloy (26% Cr-20% Ni). They listed mechanical properties of this alloy at room temperature as well as stress-rupture data and creep strength from 1400" to 2000" F., thermal expansion, and resistance to carburization and corrosion by hot gases. Carbon was found to be a n important variable, loweiing ductility a t ordinary temperatures, but increasing hot strength and life expectancy without impairing hot ductility. The effects in variation in composition of other elements are minor in comparison to carbon. Type HK alloy is stated to be the preferred cast alloy for hot gas corrosion resistance. Alloy HK fortified with 2 % silicon is well suited for carburizing service. Vermilyea (217) reports that a specimen from a Type 310 (25 Cr-20 Ni) stainless steel tube that had been in service for approximatel\ 3000 hours at 930' F. when tested for 50 hours in a boiling sulfuric acid-copper sulfate solution withstood a full 180" bend without fracture. Avery and Mathews (12) in another very complete article described the properties of the cast IIT (16 Cr-35 Ni) heat-resisting

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alloys. Typical mechanical properties at room temperature, as cast, and after aging at 1400 F., elevated temperature strength and ductility from 1400" to 2200" F., stress rupture properties, creep strength from 1400 O to 3150' F., suggested working stresses a t elevated temperatures, magnetic permeability, thermal expansion and elastic modulus at 1400" to 1800" F., resistance to carburization and hot gas corrosion, and the effect of temperature fluctuations on creep properties are given. A number of comparisons with Type 309 (25 Cr-12 Ni) are included. I n still another paper Avery (10) summarized similarly practical useful information on the cast HT (15 Cr-35% Xi) and I I U (17-21 Cr37-41 Ni) alloys. I n studying the cause of weld cracking in 15 Cr-35 Ni retorts used in the Pidgeon process for magnesium production, Il'ichols (150) reported the cracks to be due to residual welding stresses and embrittlement due to carbide precipitation. With the carbon content at 0.495, and the operating temperature 800 O to 1600' F., massive carbides were found precipitated along what appeared to be slip planes in the vicinity of the cracked welds. Laboratory sensitization of the same material in the stressed condition produced similar carbide networks. German (80) pointed out that columbium and molybdenum additions to alloys of the 15 0 - 3 5 Ni type markedly increase their creep resistance. I n tests made at 1800' F. under a load of 2000 pounds per square inch t h e standard alloy entered the third stage of creep in 50 hours. Additions of 1.9% columbium and 1.85% molybdenum increased this time to 600 and 1500 hours, respectively. Wilson (926) discussed the significance of certain specifications and test procedures in the light of the available information on cast alloys of t h e HH type (25 Cr-12 Ni). Sykes (208) covered the properties of large forgings of ferritic and austenitic stainless steels. H e emphasized t h a t the selection of the composition of alloys of optimum properties for high creep strength requires more than creep test data and that the role of the individual elements must be separately considered. A method for the separation and identification of carbides from these complex steels is given. An extensive bibliography of creep- and heat-resisting steels from 1937 to 1947 is appended. Dobltin (57) discussed the functions of the alloying elements in heat-resisting steels; his summary from the literature includes silicon, molybdenum, tungsten, columbium, titanium, sulfur, selenium, and manganese. Brasunas and Gow (26) published a very interesting series of 40 photomicrographs and two ternary diagrams for the iron-nickel-chromium system. The structures for cast alloys covering the range of 11 to 31% chromium in 5% steps and 0 t u 68% nickel in 4% steps after heating at 1800O F. for 100 hours and furnace-cooled are shown. Grant, Frederickson, and Taylor (87) published the results of an extensive research covering the properties of 53 alloys tested in the range 1200" to 1800" F. Included are stress-rupture data, creep properties, and the effect of temperature, grain size, composition, and aging on creep and stress-rupture properties. The degree of control necessary t o standardize these variables is given Freeman, Reynolds, and White (76) reported the rupture test characteristics of Types 330 (15-35), 310 (25-20), and 3105 (25-20, 0.077, maximum carbon) at 1700" and 1800" F. The properties of four experimental alloys containing columbium, molybdenum, tungsten, and boron are included. Clark and Freeman (46) in determining the high temperature properties of Types 304 (18-8), 347 (18-8-Cb), 309 (25-12), and 310 (25-20) found that the finer grained materials were in general inferior t o coarse grained materials in their high temperature load-carrying ability. For each steel the choice of proper grain size depends upon the operating temperature and the relative importance of strength and hot ductility; a coarse grain structure is recommended when strength is of primary importance. Morlet (146) confirmed the observation of Clark and Freeman of the superiority of coarse-grained over fine-grained materials. Blanter (82) measured the electrical resistance of a series of ~

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INDUSTRIAL AND ENGINEERING CHEMISTRY

chromium steels over the temperature range 70” to 2190” F. and reported that an anomalous drop that occurred upon transformation of the ferrite t o austenite and upon solution of the excess carbides in the austenite was caused by the cubic carbide (Cr, Fe)&B. Agneur, Hawkins, and Solberg (1) measured the time t o rupture of a number of materials includinglZ%Cr, 18 Cr-8 Ni, and 25 Cr-20 Ni in steam a t 1200’ F. Specimens were loaded for as long as 7700 hours; time t o rupture, elongation, reduction in area, depth of scale layer, and type and angle of fracture are given for these materials. Pugsley (165)reported that by careful inspection and strict adherence t o a maximum tube wall temperature of 1200’ F., 18-8 tubes in 1000 pounds per square inch thermal cracking units can be expected to last 60,000 service hours. While the alloy 16 Cr-25 Ni-6 hIo was developed for use in gas turbines as a heat-resistant alloy, its characteristics are such that it might have other applications. Hildorf (105) and Leslie and McPherson (12P) summarize the properties of this material. Evans ( 6 6 ) described a new alloy based on 0.3% C 19-9 modified with 1.25% tungsten, 1.25% molybdenum, 0.3% columbium, and 0.25% titanium that is reported to have an exceptionally high ratio of load-carrying ability to its total of alloying elements. He includes a description of its mechanical properties, oxidation resistance, and fabrication techniques. WELDING

Because of the wide use of 25 Cr-20 Xi that was started by its application in the welding of armor during the war, this material has received considerable attention. The ductility of 25-20 weld metal was studied by Campbell and Thomas (SQ),Linnert and Bloom (268), and Carpenter and Jessen (@), ~ h o in , the main. reported cssentiallv the same results. The optimum carbon content was reported to be 0.10 t o 0.20Oj,; Lower amounts resulted in lower ductility and tensile strength, and higher amounts lowered ductility. Silicon in excess of 0.507c r a s found by Carpenter and Jessen to result in defective weld metal due to the formation of silicate films around the austenitic grains. High sulfur and phosphorus caused fissures which seriously reduced the ductility as shown by the tensile test. Molybdenum and columbium additions reduced the microfissuring of the tensile specimens, probably because of the formation of a small amount of delta-ferrite in the matrix; when present in large amounts, these elements resulted in further loss in ductility, which is attributed to decomposition of the ferrite t o sigma phase. Lime coatings apparently can tolerate wider variations in composition than can titania coatings. It is indicated that, although fairly close control of core wire is necessary, sufficient is known of this alloy t o produce electrodes t h a t are essentially crack-free. Lee (126) classified data on 171 heats of 18-8 electrode core wire and reports t h a t (1) chromium composition should be double that of nickel, (2) carbon and phosphorus should be held t o the practical minimum, and (3) nitrogen induces crack sensitivity i n 18-8 weld metal although it does improve hot-working properties. Kihlgren and Lacy (117) studied the weld hot craclcing of the nickel-chromium alloys using their “X-weld crack test specimens,” and found that while silicon is the controlling element, its effect can be offset by the addition of ferrocolumbium in the electrode coating. The amount of columbium necessary was a direct function of the silicon content and the quantity required decreased with the nickel content of the alloys. Schaeffler (180) presented a n interesting paper in which it ishown how the microstructure and physical properties of austenitic weld metal deposit between dissimilar metals can be predicted. By converting the austenite- and ferrite-producing elements into equivalent chromium and nickel contents by means of a modified Newell-Fleischman equation and plotting them on a Maurer diagram, i t is possible t o draw “dilution lines” between any two selected compositions and predict the range of compositions that will be encountered in fusing them as in welding. Jonassen, Meriam, and DeGarmo (115) suggested the use of austenitic stainless steel electrodes for welding the plain

Vol. 40, No. 10

carbon and low alloy steels as a means of reducing the residual stresses in such joints. They pointed out that in conventional electrodes the yield point of the deposited metal frequently exceeds that of the parent stock, so that high residual stresses result. Richardson (171) found that cracks on the reverse side of oxyhydrogen and acetylene welds in stainless steel joints in which borax and borate fluxes are used may be due t o the formation of eutectics between the parent metal and some constituent in the flux. Bull (3) presented a comprehensive summary of the properties of both the ferritic and austenitic stainless and their behavior in welding. Herres and Turkalo (100) discussed the use of austenitic stainless steel electrodes in the welding of hardenable low alloy steels. Zvegintsev and Sirota (239) and Lyubarskir and Pashukanis (156) described the properties and welding procedures of two complex chromium-nickel stainless steels. Friedlander (77) patented a unique method of manufacturing welding electrodes for producing stainless steel weld deposits in which a plain carbon steel core wire is covered with a heavy coating containing both the alloying ingredients and the usual slag-forming elements. The advantages of (1) flevibility in production, (2) elimination of nire drawing difficulties, and (3) lower electrode resistance are claimed. Kelley and Fischer (115) described a method of preparing stainless steel m-elding electrodes using powdered-metal techniques. After the metal powders of ferrochromium, nickel, manganese, and iron are extruded into rods they are baked and sintered and finally swaged to size. A spray type of metal transfer across the arc is claimed for these electrodes. The practical aspects of welding stainless steel and the use of stainless electrodes in welding other materials have recieved considerable attention in the literature. Bull (34) described the effects of welding heating cycles on the corrosion resistance, structure, mechanical properties, etc., of the martensitic, ferritic, and austenitic stainless steels. Stringham (207) wrote a comprehensive article in which he considered the properties of both the ferritic and austenitic stainless alloys and applied this information to the definition of the requirements and limitations of the welding techniques t o be used in joining them. Seabloom (188) discussed the joint preparation necessary for use in the welding of stainless steel piping, and recommended welding procedures and postwelding heat-treatment. Tretiakov (31%) and Sillifant (193) considered the welding of thin sheets of an austenitic stainless steel. DeWitt and Lammers (56) wrote concerning the use of welding in the fabrication of stainless step1 bellows in jet-turbine components and described how i t was possible to train inexperienced operators to do this work successfully. Rustay et al. (36, 177, 178) discussed the pressure welding of stainless steel. They reported that stainless steel bars, tubes, and shapes could be welded and joined into mechanical parts by heating them a t the point of joining and pressing them together by the technique described by Kinzel (118). Cross sections from 1.5 to 4.5square inches could be welded readily, but it was pointed out that careful analysis was necessary t o determine the most economical method for a given job. The submerged melt welding of stainless steel and other heat-resistant alloys was described by hnderson and Roberts ( 5 ) . Gray (88) studied the furnace braaIn low carbon stainless steel and concluded tant factors are (1) minimum joint spacing, ’my surfaces, (3) oxygen-free copper, (4) avoidance of sted surfaces, and (5) use of very pure cracked ammonia as the furnace atmosphere. Elliott and Handyside (6%)cited the use of stainless steel electrodes in the repair of impellers and reported more satisfactory results than were obtained with plain carbon steel. Cunningham (5%)recounted the use of stainless steel weld metal as a hardfacing auxiliary in heavy equipment such as that used in quarries, cement mills, and earth moving. The use of multiple-tipped

October 1948

INDUSTRIAL AND ENGINEERING CHEMISTXY

acetylene torches for increasing the speed of welding stainless steel was proposed by Brotherton (32). The techniques used by a large producer for minimizing grinding and finishing costs in stainless steel weldments were presented by Schultz and Gopp (184). Richardson (17b), in considering the possible ways of protecting the reverse side of stainless steel sheet from oxidation, found t h a t helium was effective but expensive. City gas provided the good protection but resulted in some carburization of the joint . The advantages to be gained by the use of the inert arc welding process in the joining of stainless steels and other materials were described by Puffer (164), Dore (59), and Wyer (237), who included a number of operating procedures and details for welding by this process. Gibson (81) discussed the fundamental welding characteristics of stainless steel and the limitations of welding it, using argon and helium as protective atmospheres in direct current straight-polarity procedures. Conway (50) described the techniques used in the welding of a strip of Type 302 stainless steel, 200 feet x 36 ihches X 0.030 inch thick, into an endless belt by the shielded-arc method. The literature reflects the wide acceptance that the relatively new and simple means of cutting the stainless steels and other oxidation-resistant materials have attained. The principles of the three principal methods are described by Priess (165). I n one a finely divided iron powder is fed into the oxygen stream of a modified oxyacetylene cutting torch. The powder burns a t a high temperature and the combustion products provide the necessary fluxing action with the molten metal in the kerf. The second process is similar; i t employs a n oxide-eliminating flux in the oxygen stream. I n the third method, oxygen is fed through the center of a tubular coated steel electrode, thus providing the high temperature and fluxing requirements. Burch and Holub (35) have described the iron powder technique in some detail; Bellew (17-19) and Hughey (107) the flux-injection process, and Linsley ( l a g ) , Thompson (2U9), Clauser (479,and Laughner (185) the arc-oxygen process. The use of the flame-cutting of stainless and stainless clad steels in the actual fabrication of a large weldment is described by Danes (54). Fleming (68, 69) describes the application of these methods to the conditioning and scarfing of stainless steel ingots and cites the savings gained by their use. The resistance welding of stainless steel is discussed by Riley (173-175), who also presents information on flash welding. He cites the variables in preparing spot welds and in overlapping the spot welds to make seam welds. Stainless steel can be flash-welded satisfactorily, but careful control is required. Another form of resistance welding, projection welding, is described by Ochieano (152). I n projection welding a small dimple is prepared on one of the mating faces, which when fitted up t o its plane counterpart determines the area in which heating will take place. An anonymous article (8) describes an interesting nondestructive method of testing spot welds. I n this method the area surrounding the spot is placed in a magnetic field and the point of fusion is defined by the increased magnetic permeability along this path. Magnetic particles in a n oil suspension will therefore gather over the spot and define its area and shape, GENERAL

The effectiveness of beryllium as a cementation agent for 13% chromium steel and 18-8 was investigated by Laissus (184). Included i n the study were the mechanism of diffusion and the influence of time and temperature on the hardness of the product. A cone-extrusion method was employed by Sichikov, Zakharov, and Kozlova (191) for determining the yield point of highchromium stainless steels. Zappfe (289) applied fractographic techniques (examination of fracture faces) to study the structure of a series of iron-chromium alloys. The influence of manganese on the polymorphic transition in alloys of iron with chromium

1817

was investigated by Grigor’ev and Kudryavtsev ( 9 2 ) . Weil (293) studied the reflectivity of 13% chromium iron and 18-8 a t temperatures up to 300 C. Newel1 (148) discussed the properties, microstructures, and applications of high-chromium irons. The suitability of modified type 405 chromium iron as a lining for petroleum refinery vessels was discussed by Scheil (181). I n a series of articles Spencer (199-803) reviewed stainless steel classifications, properties, processing, and fabrication methods and applications. Papers on alloy selection and maintenance of stainless equipment were contributed by Mattimore (140, 141), Snair (197), F a n s (67), and Watkins and Berkol (820). French stainless steels were reviewed by Grenier (90). The effects of heat treatment on physical properties of stainless sheets and tubes were described by Campbell (58). The electrolytic polishing of stainless steel was discussed by Evans and Lloyd (66). Plankenhorn (156) considered the enameling of stainless equipment. The use of stainless steel flake in paint for corrosive conditions was described by Black ( 2 2 ) . Dale (0’3) reviewed factors involved in the production of stainless steel powder. Mehl (142) proposed the use of a sprayed metal coating, instead of powdered alumina, as a separating medium in the production of stainless-clad steel sheet by the sandwich method. Production and applications of stainless-clad steel sheet were discussed by Gosnell (85) and Carpenter (42)). Boynton (25) described the development of a nickel-manganese-chromium steel alloy for use in aircraft control cables. The problem involved here was that of matching the thermal coefficient of expansion of aluminum airframes. Carlson (41) discussed the applications of stainless steel for springs. Whitcomb (934) reported sodium carbonate t o be superior t o barium chloride for the molten saltbath heat treatment of stainless alloys. The production of stainless steel in the electric furnace was t h e subject of papers by Eisaman, Staley, Meinen, Farnsworth, Hulme, Lemmon, and Wilcox ( 3 ) . Sillers and Rasmussen (198) reported that electrolytic manganese is entirely satisfactory as a substitute for low-carbon ferromanganese in the production of stainless steel but t h a t its present cost precludes its use as this time. The application of the centrifugal casting process to stainless tubing was outlined by Moore and McKay (144). Alexander (3) described the sodium hydride process for descaling stainless steels and discussed its advantages and applications. Prevailing practices in the pressing of stainless steel were reported on by Hinman (104) and Elkington ( 6 1 ) , cupping by Higgins’(lO2), and forming by Brice (38) and Hallin (99). The use of plastic coatings in stamping operations was described by Phair (154). Fabrication and finishing techniques were discussed by Schulze (185-187), Whitesell (225), Huston ( l o g ) , Tuttle ( $ I S ) , and Seymour (189), and machining methods by von Hambach (918),Crisp and Burnam (51), and Wainwright O

(219). New books included “Stainless and Heat Resisting Steels; Simply Explained” by Gregory and Simons (89) and “Forming of Austenitic Chromium-Nickel Stainless Steels” by Krivobok and Sachs (183). HIGH-SILICON IRONS

I n spite of their poor mechanical properties, the unique corrosion resistance of high-silicon irons under conditions that cannot frequently be met by other materials qualifies them for use in1 chemical plant construction. The British Cast Iron Research Association (143) published a memorandum describing their properties, history, uses, and modifications. Hurst and Riley (108) described the characteristics of several of the structural phases present in these alloys, and the effect of other alloying elements and of foundry impurities. Rehder (167) presented alp interpretation of the constitution of iron-carbon-silicon alloys. based on new experimental data on this system. Guggenheimer, Heitler, and Hoselita (92) described a magnetic study of phase changes in iron-silicon alloys. The British Standards Institute

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INDUSTRIAL AND ENGINEERING CHEMISTRY

(99) published a list of standard dimensions of acid-resisting iron pipes and pipe fittings. Yamaguchi ($28) found by electron-diffraction examination of high-silicon iron that the acidproof surface is coated with small crystals of a-cristobalite. Karnaulrhov and Morozov (114) studied the solution of nitrogen in iron-silicon alloys and (1) found that the solubility is directly proportional to the square root of the pressure, and ( 2 ) established the existence of silicon nitride in the liquid phase. Cainbon (57) studied the optical anisotropy of silicon compounds with iron, manganese, and nickel. Traub (910) wrote a discussion of the resistance of the highsilicon alloys to Ret and dry chlorine. Luce (181, 133) contributed items on the corrosion resistance of these materials t o sodium chloride solutions and to nitric acid; Shields (190) supplied information of their resistance to phosphoric acid. NICKEL-IRON ALLOYS

The availability of a modified Type I Si-Resist alloy that is malleable and therefore of high strength and ductility was announced during the past year. Donoho (68) described the percentage composition as follows: 2.5 carbon, 2 silicon, 1.25 manganese, 15 nickel, 6 chromium, 0.1 maximum phosphorus, and 0.12 maximum sulfur. Corrosion data were given by Fontana (73). Kewell, hlanfre, and Cordovi (149) discussed the manufacture and mechanical properties of tubing containing 9% nickel. This material is reported t o be readily welded and useful for service in alkaline solutions, certain organic acids, and carbonic acid, and to maintain its mechanical properties a t low temperatures. A method for the production of iron-nickel alloys in powder form by the heating of mixed sulfates in air for reduction to the sulfides and reduction of the sulfides in hydrogen to the metals was proposed hv Chirnside (45). Delonge (58) described the use of a hard nickel-chromium cast iron in ore grinding. Information on the corrosion resistance of high-nickel austenitic cast irons to sodium chloride and to nitric acid was presented by Friend (78, 79). AUSTENITIC MANGANESE STEELS

The austenitic nisnganese steels find their principal applicat,ion in places n.here severe work-hardening under impact. renders them more wear-resistant. They are therefore used in rock crusher jaws, shovel dipper teeth, etc., where it is necessary to have an unusual combination of toughness and wear-resistance. Brodaschia (SO) made a detailed study of the iron-manganese and iron-manganese-carbon system and t’he Hadfield alloy (11 t o l4Y0 manganese) in particular and described its properties, heat treatment, and principal uses. The characteristics of coldvorlred and normalized alloys containing 26 to 48y0 manganese were reviewed by Long, Graham, and Roberson (130). The melding properties of this mat,erial were presented by Keogh ( 1 1 6 ) . Bromley ( 3 1 ) recommends the use of short, heavy beads followed by peening in the repair xwlding of dipper teeth. Ratlrowski (166) described t,he use of plug welding and interlocking joints for the repair of power shovcl dippers. Kecsner and Leffingwell (232) devised a series of pickling solutions and treatments for removing the decarburized martensitic layer formed on alloys of this type as the result of heating in mill processing. Bobiette (34),on the other hand, patented a procedure in which the material is heated a t 700” C. in a reducing gas atmosphere for decarburizing the material in the area in ivhich it is desirable to have it hardened and wear-resistant. Goss (84,85) studied the effect of heat treatment and cold rolling on the crystal structure of austenitic manganese steel by x-ray diffraction and found that delayed quenching from the annealing temperature may improve capacity for work-hardening.

Vol. 40, No. 10

ACKNOWLEDGlMENT

Thanks are due other members of the staff who assisted in the assembly of material for this review and particularly to P. H. Permar, -rho supplied the photograph for Figure 1. LITERATURE CITED

(1) Agnew, J. T., Hawkins, G. A., and Solberg, H. L., Eng. Expt. Sta. Purdue Univ., Research Ser., No. IO, 1 (1947). (2) Alexander, H. L., Iron Steel Engr., 24, No. 5 , 44 (1947). (3) Am. Inst. Mining Met. Engrs., New York, N. Y . , 1947. Electric Furnace Steel, Proceedings of Fourth Conference, 1946. (4) Am. SOC. Testing Materials, Philadelphia, Pa., “Symposium on Atmospheric Weathering of Corrosion-Resistant Steels,” 1946. (5) Anderson, R. J., and Roberts, H. J., W e l d i n g J., 26, 338 (1947). (6) Anon., Chem. Eng., 54, No. 5, 246 (1947). (7) I b i d . , No. 9, p. 214. (8) Anon., Electrician, 139,266 (1947). (9) Armbruster, M. H., J . Am. C h e m . Soc., 70, 1734 (1948). (IO) Avery, H. S., A l l o y Casting Bull. No. 9, 1 (1946). (11) Ibz’d., No. 10, 9 (1947). (12) Avery, H. S., and Mathews, N. A., Trans. Am. SOC.Metals, 38, 957 (1947). (13) Avery, H. S., and ’Wilks,C. R . , I b i d . , 40, 529 (1948). (14) Banks, F. bl.,Gas, 23, ?io. 12, 64 (1947). (15) Barnett, W. J., and Troiano, A. €I.,M e t a l Progress, 53, 366 (1948). (16) Beck, F. H., Ohio State Univ. Ena. - Euut. - Sta.. N e w s .. 19.. N o . 5, 32 (1947). (17) Bellew, G. E., I n d u s t r y and W e l d i n g , 20, 30 (1947). (18) Bellew, G. E., Steel, 120, No. 8, 104 (1947). (19) Bellew, G. E., W e l d i n g J., 27, 118 (1948). (20) Bergstrom, R. E., and Lientz, J. R., P a p e r Trade J., 124, 6 (1947). (21) Black, G., Xaterials h Methods ,27, 86 (1948). (22) Blanter, M. E., J . Tech. P h y s . (U.S.S.E.), 17,549 (1947). (23) Bloom, F. K., Gollor, G. X., and Mabus, R. G., T r a n s . Am. Soc. Metals, 39, 843 (1947). (24) Bobiette, -4. E. (to Birmingham Electric Furnaces, Ltd.), British Patent 568,573 (April 11, 1945). (25) Boynton, H. C., Materials h Methods, 25, 91 (1947). (26) Brasunas, A. de S., and Gow, J. T., Metals ProQress, 51, 777 (1947). (27) Brasunas, A. de S., Gow, J. T., and Harder, 0 . E., Am. SOC. Testing Illuteriah, PTOC., 49, 129 (1946)., (28) Brice, W. C., Materials & Methods, 26, 68 (1947). (29) British Standards Inst., London, S.W.l, Brit. S t a n d a d 1333 (1946). (30) Brodasohia, C . , Bol. assoc. brasil. M e t a i s , 3,251 (April 1947). (31) Bromley, R., I n d u s t r y and W e l d i n g , 20, 40 (September 1947). P., I r o n A g e , 157, No. 25, 70 (1946). (32) Brotherton, 5‘. (33) Bull, H., Metallurgia, 36, 137 (1947). (34) I b i d . , p. 213. (35) Burch, C. J., and Holuh. E. M., Blast Furnace Steel P l a n t , 36, 443 (1948). Bruch, C. J., Rustay, A.. L.. Crowell, A,, and Jablonski, S. A I . , W e l d i n g J . , 26, 129 (1947). Camhon, Theophile, C o m p t . rend., 224, 1112 (1947). Campbell, H. A., Iron A g e , 159, No. 23, 74 (1947). Campbell, H. C., and Thomas, R. D., V’elding J . , 25, 760-s (1946). Campbell, W. E., and Thomas, U. B., Trans. Electrochem. SOC., 91, 623 (1947). Calson, H. C. R., Product Eng., 18, 103 (1947). Carpenter, 0. R., W e l d i n g J . , 27, 279 (1948). Carpenter, 0 . J L , and Jessen, N. C., Ibid., 26, 727-9 (1947). Chevenard, P., and Wache, X., Compt. rend., 221, 442-4 (1946). Chirnside, R. C., British Patent 578,193 (June 19, 1946). Clark, C. L., and Freeman, J. W.,T r u n s . Am. SOC.M e t a l s , 38, 148 (1947). Clauser, H. R., Materials h Methods, 25, 78 (1947). Collingsworth, E. T., Chem. Eng., 55, KO.5, 235 (1948). Colner, W.H., Corrosion and Material Protect., 4, 11 (1947). Conway, R.I. J., W e l d i n g J., 26, 791 (1947). Crisp. T V . H., and Burnam, W.,M a c h i n e r y ( L o n d o n ) , 70, 9 (1947). Cunningham, J. A., W e l d i n g E n g r . , 33, 40 (1948). Dale, J. D., Proc. T h i r d Ai~nzialSpring J l e e t i n g , M e t a l Powder Assoc., 4 (1947). Danes, S. F., Materials & Methods, 26, 102 (1947). Delonge, K. A., Eng. M i n i n g J . , 147, No. 10, 60 (1946). DeWitt, E. J., and Lammers, F. J., W e l d i n g J.,26, 320 (1947).

October 1948

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INDUSTRIAL AND ENGINEERING CHEMISTRY

Dobkin, H., Steel, 117, No. 18, 78 (1946). Donoho, C. K., Materials & Methods, 26, No. 3, 85 (1947). Dore, R. E., She& M e t a l I n d s . , 23,2405 (1946). Dravnieks, A., and McDonald, H . J., J . Electrochem. Soc., 93, 177 (1948). Elkington, T. W., Sheet M e t a l I n d s . , 24, 1603 (1947). Elliott, W. L., and Handyside, G., Steel, 122, No. 15,82 (1948). Emmanuel, G. N . , M e t a l Progress, 52, 78 (1947). Esgar, H . C., Chem. M e t . Eng., 53, No. 8,203 (1946). Evans, C. T., Jr. (to Universal-Cyclops Steel Corp.), U. S. Patent 2,416,515 (Feb. 25, 1947). Evans, H., and Lloyd, E. H., Metal I n d . ( L o n d o n ) , 71, 10 (1947). Faris, C. H., J . J u n i o r I n s t . E n g r s . ( L o n d o n ) , 57, 335 (1947). Fleming, D. H., Steel, 121, No. 22, 96 (1947). Fleming, D. H., W e l d i n g J . , 26,201 (1947). Fontana, M . G., Corrosion, 3, 56 (1947). ENG.CHEM.,39, No. 6, 103 A (1947). Fontana, M. G., IND. I h i d . , 39, No. 12. 91 A (1947). I b i d . , 40, No. 2 89 A (1948). Ibid., 40, No. 2, 89 A (1948). Fontana, M. G., and Beck, F. H., M e t a l Progress, 51, 939 (1947). Freeman, J. W., Reynolds, E . E., and White, A. E., Natl. Advisory Comm. Aeronaut., Tech. Note 1465 (February 1948). Friedlander, E. F. (to 0. & F. Co., Ltd.), U. S. Patent 2,408,620 (Oct. 1, 1946). Friend, W. Z., Chem. Eng., 54, No. 12, 225 (1947). Ibid., 55, No. 4, 219 (1948). German, H . M . (to Driver-Harris Co.), U. S. Patent 2,408,771 (Oct. 8, 1946). Gibson, J. G., W e l d i r ~ g J .26, , 282-s (1947). Glikman, L.A., and Stepanov, V. A,, Boiler and T u r b i n e Construction U . R . S . S . , 19 (February 1947) Gosnell, E. C., Corrosion, 2, 287 (1946). Goss, N. P., Steel, 121, No. 13, 74 (1947). I h i d . , 121, No. 14, 98 (1947). Gow, J. T., Corrosion, 3, 311 (1947). Grant, N. J., Frederickson, A. F., and Taylor, M. E., I r o n A g e , 161, No. 12, 73 (1948). Gray, T. H., Steel, 121, No. 3, 104 (1947). Gregory, E., and Simons, E . M., “Stainless and Heat-Resisting Steels Simply Explained,” London, Hutchinson’s Scientific & Technical Publications, 1947. Grenier, C., C h i m i e & I n d u s t r i e , 56, 456 (1946). Grigor’ev, A. T., and Kudryavtsev, I. V., B u l l . acad. sci. U.R.S.S., Classe sei. chim., 329 (1947). Guggenheimer, K . M., Heitler, H., and Hoselitz, K.,J . I r o n SteeE I n s t . ( L o n d o n ) , 158, 11, 192 (1948). Guitton, L., Compt. rend., 226, 805 (1948). Guitton, L . , M e t a l Treatment, 15, 3 (1948). Guitton, L., M d t a n z & Corrosion, 22, 47 (1947). Ihid., 23, 29 (1948). Gulbransen, E. A., T r a n s . Electrochem. Soc., 91, 573 (1947). Gulbransen, E. A,, Phelps, R. T., and Hickman, J. W., IWD. ENG.CHEM.,ANAL.ED.,18, 640 (1946). Hallin, P., M a c h i n i s t , 90, 1999 (1947). Herres, S. A., and Turkalo, A. M., W e l d i n g J., 25, 669-5 (1946). Hickman, J. W., and Gulbransen, E. A,, T r a n s . Electrochem. Soc., 91, 605 (1947). Higgins, C. C., M e t a l Progress, 51,443 (1947). Hildorf, W. G., W e s t e r n M a c h i n e r v a n d Steel W o r l d , 38, 126 (1947). Hinman, C. W., Steel Processing, 33, 355 (1947). Hobson, P. T., and Osmond, W. P., N a t u r e , 161, 562 (1948). Hubbell, W. G., Steel, 119, No. 27, 86 (1946). Hughey, H . G., W e l d i n g J . , 26, 393 (1947). Hurst, J. E., and Riley, R. V., J . I r o n Steel I n s t . ( L o n d o n ) , 155, 172 (1947). Huston, K . M., Steel, 122, No. 23, 106 (1948). Ihrig, H. K., T r a n s . Electrochem. Soc., 91, 641 (1947). Jack, D . E., Chem. Eng., 53, No. 9, 203 (1946). Jaskewich, A., and Samarin, A., B u l l . acad. sei. U.R.S.S., Classe sei. tech., 595 (1946). Jonassen, F., Meriam, J. L., and De Garmo, E. P., W e l d i n g J., 25, 489-s (1946). Karnaukhov, iM.M., and Moiozov, A. N., B u l l . acad. sci. U.R.S.S., Classe sei. tech., 6 , 735 (1947). Kelley, F. C., and Fisher, F. E., Ir07L A g e , 158, No. 25, 68 (1946). Keogh, C. P., M o d e r n Engineer, 18, 39 (1944). Kihlgren, T. E., and Lacy, C. E., W e l d i n g J., 25, 769-2 (1946). Kinzel, A. B., Ihid., 23, 1124 (1944). Kirkby, H . W., and Morley, J. I., J . I r o n Steel I n s t . ( L o n d o n ) , 158, 289 (1948). Kirtchik, H., I r o n Age, 159, No. 10, 67 (1947).

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(121) Kornilov, I. I., and Shpikel’man, A. I., Compt. rend. acad. sci. U.R.S.S., 53, 805 (1946). (122) Ibid., 54, 511 (1946). (123) Krivobok, V. N., and Sachs, G., “Forming of Austenitic Chromium-Nickel Stainless Steels,” New York, International Nickel Co. (limited distribution), 1947. (124) Laissus, J., Compt. rend., 224, 742 (1947). (125) Laughner, V., M a c h i n e r g , 53, 174 (1947). (126) Lee, R. K., MetalProgress, 51,445 (1947). (127) Leslie, W. C., and McPherson, D. J., Ohio State Eng. Expt. Sta., News, 19,42 (1947). (128) Linnort, G. E., and Bloom, F. K., W e l d i n g J . , 26, 119 (1947). (129) Linsley, 13. E., I r o n A g e , 158, No. 20, 96 (1946). (130) Long, K. R., Graham, T. R., and Roberson, A. H., T r a n s . Am. SOC.Metals, 40, 401 (1948). (131) Luce, W. A., C h e m . Eng., 54, No. 11, 217 (1947). (132) Ibid., 55, No. 16, 223 (1948). (133) Ihid., 55, No. 3, 225 (1948). 1134) Ihid.. 55. No. 6. 223 (1948). (135j Lyubarskii, K.’V., and Pashukanis, F. I., Autogennoe Delo, No. 8 19. 8 (1946). (136) McAdam,‘D. J:, Geil, G . W., and Cromwell, F. J., J . Research h’atl. Bur. Standards, 40, 375 (1948). (137) MoCullough, H. M., Ohio State Univ. Eng. Expt. Sta., News, 19, No. 5 , 38 (1947). (138) Mahla, E. M., and Nielsen, N. A,, J . A p p l i e d P h y s i c s , 19, 378 (1948). (139) Mahla, E. M., and Nielsen, N. A., J. EEectrochem. Soc., 93, 1 (1948). (140) Mattimore, J. D., Heating, P i p i n g A i r Conditioning, 19, 81 (1 F147).

(141) Ihii:,-i9: .84 (1947). (142) Mehl, R. F. (to Jessop Steel Co.), U. S. Patent 2,416,400 (Feb. 25, 1947). (143) Ministry of Supply, Bull. F o u n d r y Abstracts B r i t . Cast I r o n Research Assoc., 8, 160 (1946); M e m . 19. (144) Moore, J . W., and McKay, J. W., Am. F o u n d r y m a n , 13, 41 (1948). (145) Morlet, E., M k t a u z , corrosion, usure, 19, 1 (1944). (146) Mott, N. F., J . chim. phys., 44, 172 (1947). (147) Mott, N. F.,T r a n s . F a r a d a y Soc., 43,429 (1947). (148) Newell, H . D., M e t a l P r o g r e s s , 51, 617 (1947). (149) Newell, H. S., Manfre, J. A , , and Cordovi, M. A , , Materials & Methods, 25, 62 (1947). (150) Nichols, H . J., W e Z d i n g J . , 26, 881 (1947). (151) Nicholson, J. H., and Kwasney, E. J., T r a n s . Electrochem. SOC. 91, 681 (1947). (152) Ochieano, M . L., Product Eng., 18, 117 (1947). (153) Payson, P., and Savage, C. H., T r a n s . Am. Soc. M e t a l s , 38, 404 (1947). (154) Phair, W. A., I r o n A g e , 159, No. 20,47 (1947). (155) Phillips, F. J., T r a n s . A m . Soc. M e t a l s , 39, 891 (1947). (156) Plankenhorn, W. J., Elaamelist, 24, 8 (1947). (157) Plankensteiner, S., I n d u s t r i e & T e c h n i k , 2, 16 (1947). (158) Plankensteiner, S , Metallurgia, 36, 145 (1947). (159) Post, C. B., and Eberly, W. S., T r a n s . Am SOC.M e t a l s , 39, 868 I1 947)

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(160) P r a t t , Tf..E,, Chem. Eng., 53, No. 7, 221 (1946). (161) Ibid., 54,No. 10, 211 (1947). (162) Pray, H . A , , Fink, F. W., and Peoples, R. S., R e p t . I t o Am. Gas Assoc. (February 1947). (163) Priess, R., Southern P o w e r a n d l n d . , 66, 62 (1948). (164) Puffer, D. W., Steel, 119, No. 21, 80 (1946). (165) Pugsley, C. S., Petroleum Refiner, 26, 119 (1947). (166) Ratkowski, T. A , , W e l d i n g E n g r . , 32, 54 (1947). (167) Rehder, J. E., Am. Foundrymen’s Assoc., Preprint 47-11 (1947). (168) Renshaw, W. G., Chem. Eng., 55, No. 5, 242 (1947). (169) Ronshaw, W. G., Petroleum Processing, 3, 25 (1948). (170) I h i d . , 3, 155 (1948). (171) Richardson, G., I r o n A g e , 159, No. 16, 43 (1947). (172) Ihid., 159, No. 18. 72 (1947). (173) Riley, J. J., Am. M a c h i n i s t , 90, No. 23, 112 (1946). (174) I b i d . , 90, No. 24, 108 (1946). (175) I h i d . , 90, No. 25, 134 (1946). (176) Rosenberg, S. J., and Darr, J. H., J . Research N a t l . B u r . Standards, 40, 321 (1948). (177) Rustay, A. L., M e t a l Progress, 52, 238 (1947). (178) Rustay, A. L., Crowell, A , , Jablonski, S. M., and Burch, C. J., W e l d i n g J . , 26, 129 (1947). (179) Sarkisov, E. S., Bzdl. A c a d . S e i . Georgian S.S.R., 3, 1043 (1942). (180) Schaeffler, A. L., W e l d i n g J . , 26, 601-s (1947). (181) Scheil, M . A., M e t a l Progress, 52, 91 (1947). (182) Schoefer, E. A., A l l o y Casting BuU. 10 (1947). (183) Schrader, R . J., and DeHaan, A,, C h e m . Eng., 53, No. 11, 96 (1946).

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(184) Schults, H. H., and Gopp, G., I n d u s t r y a n d W e l d i n g , 21, 26 (1948). (185) Schulze, A. P., X e t n l F i n i s h i n g , 46, No. 1 , 7 2 (1948). (186) I b i d . , 46, KO.2, 59 (1948). (187) I b i d . , 46, No. 3, 62 (1948). (188) Seabloom, E. R., Heating, P i p i n g Air Conditioning, 18, 79 (1946). (189) Seymour, H., Petroleum, 10, 85 (1947). (190) Shields, R. M., Chem. Eng., 53, X o . 9, 212 (1946). (191) Sichikov, M. F., Zakharov. B . P.. and Kozlova. I. V.. Zauodsk a y a Lab., 13, 854 (1947). Sillers, F., and Rasmussen, R. T. C., 11. S. Bur. Mines, R e p t . Invest. 4078 (1947). Sillifant, R. R., Welding,14, 557 (1946). Smith, L., and Bowen, K. W.J., J . Iron SteeZ I m t . ( L o n d o n ) , 158. 295 (1948). Snair, G . L.,’Che&. Eng., 55, No. 1, 230 (1947). Ibid., 55, No. 3, 228 (1947). Snair, G. L., R e f r i g . , Co2d Storage, Air Conditioning, 18, KO.3, 39 11047). Spefght, G.E., J . SOC.D a i r y Technol., 1, 8 (1947). Spencer, F. L., Steel Processing, 33,474 (1947). I b i d . , p . 624. Ibid., p. 755. I b i d . , 34, 127 (1948). I b i d . , p. 198. Springer, M. H., Succop, E . V., McKirmey, D. S., and Scheil, hf. A., W e l d i n g J . , 26, 530-s (1947) Stauffer, W.,and Kleiber, II., J . I r o n Steel Inst. ( L o n d o n ) , 156, 181 (1947). Stewart, R. S., Metal Progress, 52,971 (1947). Stringham, L. K., Iron A g e , 160, No. 9, 61 (1947).

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COURTESY MYCALEX CORPORATION OF AMERICA

Glass-Bonded Mica Parts 14.

15.

Vol. 40, No. 10

Insulator for polarizing relay 19,ZO. Aotuating bar for telephone relay Lead through block, for oscillator 21. Spacer for radio vibrator 22. Panel for television selector switch