Stainless Steels and
Other Ferrous Alloys HUGH B. FISCHER
T""' uvemenb f a mat&& of construction in chemical and p t r a h r m i c a l plants today arc both varied and detailed. Plane have become larger and more competitive. Proease have become m m e v e and q u i r e equipment which will operate satisfactaily at g r c a m extrtmes of temperature and pressure. It is d y no longer pmsihle, and certainly not economical, to rpec* ollc or two materials of construction throughout a specific chemical proecsd. T o meet present-day r e q u h e n s , numerous wmpetitive
materiala have bccn developed. Many technical p a p and much a d w W i literature d m i b q the properties and intended usen of tbcsc m a t d a b have been puhlished. T h e chemical or materials engineer who must select the materials of construction faa ehemical plant a maintain that plant has to collect and analyze thii largc m a n of data to -e that the proper mat& arc w d . To aid in th!! w a k , the -nt rewill disuas recently publiahcd data pertaininB to the stainless steels and other f m u a alloys. Tk following general arcas will be diacuaxd: Materials Selection, CerrcaBion Resistance, New Alloys, New Manufacturing Techniques, and Welding. MdalmbW.n*n
Artides puhliahed in 1966 to 1967 w m reported in last year's annual rtvicW (4A). A list of available materials of construction lad manufacturrn has bccn compiled (73A). A general review d the development of high strength structural steela has been publirhed (6A). The q u i r r m e n e of constructional steels and the challenge to usc cwnomical materials have been noted (77A). The nced fameaningful qxcificatiom and the d s t a of alloy
additions and &dual elemene on properties arc shown. The kind. of stainless steels available d a y have been d d b e d with rcapeet to mechanical properties, general cormsion reaiStanee, and mdurgical properties ( 7 4 3 4 9A). The q x c f i a t i o n s for 42 widely rucd American and Britirh austenitic stainless steela (3A), 38 German stainlcsd atcels (9A), and several new Russian stainless ,tal ( I A ) arc Luluded. T h e e are good general artidw, hut do not contain enough data to parnit the eelcction of materials fa rpci6c applications. A mom detailed acwunt of the micms m ~ r e s ,effects of alloy additions, problems encountered in lnboramryc d n tats, as well as the wmpoeitions and mechanLal -tLa of the atainlcSd steels, has been published (75-4). The rclection of stainla, steels for elevated temperature service (8A) and f a cryogenic and ambient temperature service (2A) has W n d k d . &, &t review of the creep-rupture propertics of metals and alloys ha8 been prmented (SA). The dece of such itans as 42
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
alloying, solute atoms, grain size, and lattice strain on pmprt*r arc diruared, and the miavsrmctural ehangca which take place during creep arc darribed. The review contains 159 references. The method. of selecting steels to be u a d at 1000 to 20WDP have been described (7A). C m p data, oxidation resistance, and the temperature Limitations of ditrerent alloy8 arc ahown. T h e resde of an international cmp-rupture tcating program on the widely used 2'/& -1% M a low alloy steel have been reported (IOA). Creep data, the dece of eaPnpmition on strength and c-ion resistance. and other performaw data have been d e m mined for the widely uaed cast, heat-resistant alloys, HC through Hx (724). A welldocumented reof the p e n t state of the art of pmduction of s t a i n l d a d carbon steels has been prracnted (74A). Cladding by rolling, welding, casting. and explosive charge is dircuancd. C h m k d and P.korh.mic.al Indushy
The selection of materials of construction for chemical plants has been outlined (IB). T h e iduencc of design, cwnomiu, availability, and maintenance pmblrms on selection is considered. Several stainless steels intended for s e v e d y corrosive service in the chemical induatry have been dcaaibed (48,58, 78,88). A number of specific applications arc mentioned. Heat-resistant steels f a long time, high-temperature 8avicc in the chemical and petmchemical industry have been evaluated (28). Recent developmcne are outlined, and creep data are ahown. The use of austenitic steel castinga in the chcmical industry, especially for pumps and v a l w , has been documented
(98). The suitability of carbon steels, low alloy steels, and stainless
steels for low temperature service bas been inwtigated (708). Low-tcmperature properties, ductile-to-brittle tramition temperature, and economic selection of materials are diruased. Nine failures of wcldcd chemical equipment from rmbrittlement at low temperatures have been studied (68). The use of 2 to 9% nickel ateels and austenitic stainlcsr steels f a vanels and piping in low-temperature service has been reported (38).
SpwMs Chemkd Pm-s The following references p e n t actual plant data on ma-
terials of construction in specific chemical pmcaurs. The arcas of the plant where the materials were used a8 well as the spaific chemical envimnmene to which the materials were wpased
Materials selection, corrosion resistance, new alloys, new manufacturing techniques, and welding are the topics covered by this year’s review on ferrous materials and their use in chemical plants
are usually described. Both failures and satisfactory applications are shown. Materials of construction in nitrogen fertilizer plants have been documented. More stainless steels are being used in many areas of these plants despite relatively high initial costs (9C). Some of the specific widely used stainless steels have been described (5C). The successful use of carbon steels in inhibited nitrate solutions has been reported (ZC). Methods of minimizing corrosion in ammonium nitrate neutralizer vessels have been discussed ( 75C), and corrosion problems in fertilizer plants have been outlined ( 3 C ) . General maintenance problems in urea plants, including corrosion of valves and piping, have been summarized (27C). Traditionally, ferrite-free austenitic alloys have been specified for urea synthesis. Methods of reducing ferrite in austenitic stainless steel welds, thus improving the corrosion resistance of these alloys in urea plants, have been developed (72C). A survey of corrosion problems in 24 reformer hydrogen plants has been published (42). These problems generally occurred in four areas: sulfur removal units, stainless steel flexible hose connections to reformer furnaces, reformer effluent heat exchangers, and carbon dioxide removal units. Remedies for these problems are suggested. Failures of reformer tube “pigtails” in ammonia plants have been studied ( I C ) . Problems associated with boiler water carryover into steam-methane reforming furnaces have been investigated (7C). Composite reformer furnace tubes have been developed made of 11/4% Cr-l% M o low alloy steel in the portion of the tube exposed to relatively low temperatures, 1896 Cr-870 Ni stainless steel in the portion exposed to intermediate temperatures, and 25% Cr-20% Ni or 80% Ni-l5% Cr alloys in the portion exposed to high temperatures (8C). These tubes are more economical than the widely used 25y0 Cr-20yO Ni (HK-40) alloy reformer tubes. A low chromium alloy steel, refractory concrete-lined converter has been used for ammonia and methanol synthesis (6C). The converter can be made of economical steels without danger of hydrogen embrittlement because the vessel shell is cooled externally to less than 250°F. A survey of the actual performance of 22 monoethanolamine (MEA) gas scrubbing plants has been made (23C). Most of the problems in these plants were associated with reboilers and other heat exchangers. Specific recommendations to overcome the problems are presented. Sodium metavanadate has been effective as a n inhibitor in preventing corrosion in these plants (77C, 28C). The best materials of construction for phosphoric acid evaporation processes have been determined (7OC). An alloy similar to Alloy 20 was found to be the best material in the most corrosive parts of the system. Anodic protection of carbon steel vessels has been successful in some areas of phosphoric acid plants (ZOC). VOL. 6 1
NO. 8
AUGUST 1 9 6 9
43
Materials problems in the production of superphosphoric acid by vacuum concentration have been studied (27C). Stabilized 17yG Cr stainless steels have been used in European nitric acid plants ( 7 9 C ) and are the economic choice in many areas. I n the United States, the austenitic stainless steels are relatively more economical than in Europe, and today are generally preferred to the 177, Cr steels in practically all areas of nitric acid plants. The applications of various stainless steels in the pulp and paper industry have been described (24C). The successful use of stainless steels in the production of synthetic fatty acids has been documented (14C). The materials of construction used in the various processes for making formaldehyde have been noted (76C). The use of lined-steel vessels in potash plants (22C), stainless steels in coke plants (17C), and stainless steels in a synthetic rubber plant (18C) has been reported. T h e corrosion resistance of materials in water desalination plants has been summarized (25C). Stainless steel stress corrosion cracking problems in an air liquefaction plant have been investigated (26C). Alloys suitable for the storage of liquefied gases have been described (73C). Specific Chemical Equipment
A review of the design, specifications, and materials of construction for shell and tube heat exchangers has been published ( 1 2 0 ) . T h e importance of proper specifications is stressed and what proper specifications are is discussed. T h e use of seamless vs. welded tubes is also discussed. The fabrication of heat exchangers has been described (130). T h e design and performance of plate heat exchangers have been studied ( 1 6 0 ) . The materials of construction for these units are included. T h e materials and methods of construction of high-temperature high-pressure heat exchangers, such as those used in reformer hydrogen plants have been outlined (7OD). The suitability of various materials for use in heat exchangers for high-pressure steam power plants has been reviewed ( 4 0 ) . This review includes 607, Cr-407, Ni, 267, Cr-3Y0 Al, and 147, Cr-147, Ni-37, W alloys in addition to the widely used stainless steels. Various corrosion problems in heat exchangers, such as impingement attack in carbon steel units (6D),cavitation in stainless steel units ( Q D ) , sulfide corrosion in hydrocracker coolers ( I I D ) , chloride stress corrosion cracking in stainless steel units ( I D ) , and general corrosion in stainless steel sea water condensers (ZD), have been reported. Methods of solving these problems are shown. Materials for chemical process piping have been reviewed (70). The design of piping systems is illustrated. Comparative costs of piping constructed from numerous different materials have been tabulated (80). T h e effects of design, materials, fabrication, and service conditions on the use of piping in high-temperature service have been evaluated (750). There are many examples of failures and analyses of these failures in this extensive article. Mechanical properties and corrosion resistance of low alloy and stainless steel petroleum refinery piping materials have been summarized ( 770). Successful applications of centrifugally cast stainless and low alloy steel pipe and piping components in refinery piping systems have been documented (30). Some cast piping components have been in service as long as 12 years without any problems. Corrosion protection and maintenance of a stainless steel sulfite pulp digester have been detailed (50). The problems of pitting, intergranular corrosion, stress corrosion cracking, and galvanic corrosion are considered. High silicon cast iron pumps have been recommended for service in many corrosive environments (740). Boilers and Pressure Vessels
Design criteria for heavy-wall pressure vessels have been published (71E,ZOE, 23E). Division 1 and Division 2 requirements of the ASME Boiler and Pressure Vessel Code are compared (ZOE,23E). The new Division 2 requirements allow higher stresses than the well-known Division 1 requirements, but specify more stringent design and inspection procedures. Large, heavywall vessels generally can be constructed more economically under Division 2 than was possible under Division 1. The materials of construction permitted under both divisions of this code are also listed. German requirements have been documented (7 1E). Various types of large pressure vessel construction, such as forged single wall, multilayer, and strip wound, have been described (24E). T h e use of multilayer and strip-winding techniques permits savings not only because of design considerations, but also because of the superior mechanical properties of the thinner steel 44
INDUSTRIAL A N D ENGINEERING CHEMISTRY
sections required. Current design and fabrication practice for nuclear pressure vessels has been reviewed (2223). The metallurgy of the low alloy steels commonly used in this application is considered with emphasis on fracture mechanics and crack growth. New data which permit the wider use of 2l/47, Cr-17’ M o low alloy steel for pressure vessels such as hydrocrackers and catalytic reformers have been presented (7046E). A review of the steels used for high-pressure boiler drums has been made (2E). The use of Cr-Mn-Ni stainless steels for steam superheaters has been described (9E). Maintenance and safe operation of high-pressure equipment have been outlined (74E). Types of failures are discussed. A small (120-1.) pressure vessel has been fabricated from explosively clad, tantalum-on-steel plate (5E). The procedures applicable to larger vessels are described. T h e problem of hydrogen damage to boiler tubing has been investigated ( 7 E ) . Generally this damage is caused by hydrogen produced during some kind of corrosion process. The protection of multilayer vessels from high-pressure hydrogen, carbonyl, and hydrogen sulfide attack has been studied ( 7 E ) . Severe corrosion on the fire side of high-pressure boilers which burn residual fuel oil containing vanadium and sulfur continues to be a widespread problem. Much has been published recently in this area. The use of inhibitors in the fuel oil to change the composition of the ash appears to be the most effective remedy. The use of more highly alloyed steels and other alloys such as 607, Cr-40YG Ni is also effective in some instances. Good descriptions of this corrosion problem have been published (4E, IOE,77E, 79E). The use of inhibitors (8E,lOE,17E,79E) and the use of better alloys ( I Z E , 76E, 77E, 21E)have been evaluated. The inspection of pressure vessels has become more critical because of the increased use of lower safety factors and higher strength, quenched and tempered low-alloy steels in the fabrication of these vessels. Current preferred inspection techniques have been documented (13E, 18E). Radiographic examination ( 3 E ) and a new system of leak detection (75E)have been described. Corrosion Resistance
The importance of adequate corrosion resistance in chemical plant equipment cannot be overemphasized. I t is usually difficult to apply raw corrosion data directly to the process in question when selecting equipment and the materials of construction for that equipment. Good basic corrosion data are very helpful in eliminating some candidate materials, however, and thus in narrowing the choice. Large amounts of this kind of corrosion data are published each year to aid the materials or chemical engineer in his selection. Some of the recent articles of general interest-in fundamentals, in specific data, and in some special phenomenaare discussed below. Corrosion principles have been very well set forth for the serious student of corrosion ( I F ) and, with more emphasis on practical problems, for the maintenance engineer ( 7 F ) . Sources of general corrosion data include a new edition of Rabald’s Corrosion Guide (ZF),which is a handbook of corrosion tables; and a literature review ( 6 F ) with 115 references. Methods of controlling corrosion by process design such as neutralization, dehydration, or deaeration of process streams have been reported (5F). The special problem of corrosion at flanged joints has been studied ( 4 F ) . Corrosion under heat transfer conditions has been reviewed (3F). T h e effects of heat flux, temperature gradients, velocity, and other variables upon corrosion rates are shown. Heat transfer conditions almost always increase corrosion rates regardless of the direction of the heat flow-i.e., regardless of whether the metal surface is hotter or cooler than it would be if there were no heat flow. Specific Corrosion Data
The corrosion resistance of low alloy steels in a large variety of chemical environments has been documented (2G). The corrosion resistance of stainless steels in many different aqueous solutions (2OG) and at elevated temperatures ( 2 7 G ) has been summarized. The problems of pitting corrosion (SG),intergranular corrosion (IG),and knife line and intergranular corrosion of welded joints
AUTHOR Hugh B. Fischer is Staff Metallurgist in the Central Engineering Department, Hercules, Inc., Wilmington, Del. 19899. This is his second annual review on this subject INDUSTRIAL AND ENGINEERING CHEMISTRY.
(7G) in stainless steels exposed to various environments have been described. The effect of chemical composition on corrosion resistance of the free-machining austenitic stainless steels has been investigated (2%). I n most environments, the standard Type 303 stainless steel had the worst corrosion resistance. Types 303 Se, 303 MA, and 303 Pb were progressively better. The effects of alloying additions on the corrosion resistance of Type 430 stainless steel exposed to several strong acids have been reported ( 3 G ) . Additions of about 3% Mo produced corrosion resistance almost equal to that of Type 304 stainless steel in sulfuric, hydrochloric, and nitric acids. The corrosion resistance of austenitic stainless steels in nitric acid has been determined (77G, 78G). The effects of molybdenum additions (79G), ultrasound (76G), chloride ions (76G), welding (77G),surface finish (6G), and carbon content (6G) on the corrosion resistance of austenitic stainless steels in nitric acid have been studied. I t was found that molybdenum additions, ultrasound, and electropolishing all increased the rate of corrosion. In 9975 nitric acid, the addition of chloride ions decreased the corrosion rate. The corrosion of austenitic stainless steels in acetic acid (28G), citric acid (4G), and phosphoric acid (IOG, 22G) has been investigated. The corrosion of steels by alkali nitrates and the inhibitive effect of nitrites in ammonium nitrate solutions have been reported (7ZG). The corrosion resistance of steels in liquid and gaseous sulfur and its compounds was improved greatly by additions of aluminum (27‘2). Steels containing 4y0 A1 were as resistant as 13y0 Cr steels, and steels containing more than 10% A1 were excellent. The effects of inorganic contaminants in chlorinated organic solvents on the corrosion resistance of steel and Type 304 stainless steel have been evaluated (8G). Dissolved water and hydrochloric acid (produced from the degradation of the solvents) produced severe corrosion in these alloys. The corrosion resistance of steels and stainless steels in sea water has been documented (75G). The resistance of cast steels (5G) and wrought steels (23G) to atmospheric corrosion has been summarized. Twelve-year exposures of cast steels showed that these were superior to malleable iron and equal to or better than wrought steels. The corrosion problems in the construction industry and the successful use of low alloy steels which form protective corrosion products have been described (23G). Long-time exposures of ductile (nodular) cast iron in several different soils showed that its corrosion resistance was equal to that of gray cast iron (24G,25G). The corrosion resistance of aluminum-, zinc-, and chromiumcoated steels in many different chemical environments has been reported (73G, 7 4 2 ) . Stress Corrosion Cracking
Stress corrosion cracking and hydrogen embrittlement are two special phenomena associated with corrosion responsible for many catastrophic failures of equipment in chemical plants. The cause of these brittle failures is not too well understood despite much research work in this field. Recently there has been renewed support for the surface energy theory of stress corrosion cracking. This is a more fundamental theory than the electrochemical theory and well describes the mechanism of attack by liquid metals and the stress cracking of nonmetals. With respect to ferrous alloys, however, there appear to be more proponents of the electrochemical theory. Several good reviews of stress corrosion cracking theory have been published recently (4H, 5H, 8H, 73H). Stress corrosion cracking occurs to specific materials in specific environments. Recent work which has further defined the limits of susceptibility of some of the ferrous alloys is described below. The effects of oxygen and chloride ions on the cracking of Type 321 stainless steel have been reported (70H). When the oxygen content of the solution was less than 0.1 mg/l., there was no cracking even when the chloride ion concentration reached 1 g/l.; but when the oxygen content was 3 mg/l., the specimens cracked a t a chloride ion concentration of 0.1 mg/l. The cracking of Type 321 stainless steel has been found to be very dependent upon the p H of the environment ( 9 H ) . Cracking susceptibility was greatest a t a p H of 4 to 5. Nitrogen additions increased the cracking susceptibility of Type 304 stainless steel ( 6 H ) . Aluminizing Type 304 stainless steel prevented cracking in certain instances (79H). The effects of composition on the cracking of ferritic stainless steels have been studied ( 3 H ) . Steels containing only 17 to 25% Cr and 0 to 570 Mo did not crack in chloride solutions. Additions of nickel, copper, or cobalt to these steels produced cracking even though the steels were still completely ferritic.
The susceptibility of high strength steels to cracking by hydrogen sulfide has been outlined ( 7 2 ” ) . The effects of strength, welding, heat treatment, and alloy additions on cracking susceptibility were considered. A good review of this problem including many case histories has been compiled ( 7 7H). Steels containing uniform spheroidized carbides have better resistance to this cracking than steels containing untempered martensite (20H). An instance of sulfide stress cracking of compressor components in a refinery has been documented (74H). Several reviews of the problem of hydrogen embrittlement have been presented (7H, 75H, 76H, 77H). A method for estimating the time to failure a t various strength levels has been developed for steels exposed to environments in which hydrogen embrittlement can occur (78H). The resistance to hydrogen embrittlement of steels used in ammonia synthesis has been determined ( Z H ) . The problem of embrittlement of unstable austenitic stainless steels by high pressure hydrogen has been studied ( I N ) . New Alloys
New alloys of interest to the chemical industry include three alloys designed to be resistant to stress corrosion cracking. The background, mechanical properties, corrosion resistance, and applications of U. S. Steel’s 18-18-2 alloy have been reported ( Z J ) . This three-year-old alloy, reviewed in the past, is now finding applications in chemical plants. I t contains 0.06% C , lSyo Cr, 18% Ni, 2% Si, 1.5y0 Mn, 0.00770 P, 0.00970 S, 0.0470 N. Its mechanical properties are generally comparable to those of Type 304 stainless steel. Firth-Vickers, FV-702, is a new ferritic stainless steel which has fairly good general corrosion resistance and is resistant to stress corrosion cracking ( 4 J , 8 J ) . I t contains 0.0370 C, 16% Cr, 2.5% Ni, 0.6% Mn, 1.07, Mo, 0.570 Si, 0.5570 Cb. Corrosion resistance, mechanical properties, and weldability are presented. A new austenitic stainless steel, resistant to stress corrosion cracking in sea water, has been developed in Austria (725). It contains 0.03y0 C, 24y’ Cr, 14% Ni, 7% Mn, 27, Mo, 1% Si, 0.4% N, and small amounts of several other elements. A new Russian stainless steel with superior corrosion resistance in sulfuric acid solutions has been reported ( 7 4 J ) . I t contains 0.04y0 C, 19% Cr, 20% Ni, 2.6y0 Mo, 3y0 Si, 2.4% Cu, 0.370 Cb. I t is especially effective in concentrations of sulfuric acid below
45%. Four reports of new high-strength, nitrogen-bearing, austenitic stainless steels have been published (5J,8J, IJ, 77J). The addition of 0.15 to 0.20y0 nitrogen to Type 304 or 316 stainless steel increased yield strength about 50% and ultimate tensile strength about 2070. Corrosion resistance was generally unchanged. New developments in structural steels have been summarized (35, 7 5 ) . Strengths have been increased by higher carbon content; manganese, columbium, and nitrogen additions; controlled rolling practices; and special heat treatments. Use of a new modified cast H F alloy in hydrocracker service has been described ( 7 U J ) . I t contains 0.25% to 0.3570 C , 21 to 29% Cr, and 6 to 11% Ni, and has 5 to 15y0 ferrite in an austenitic matrix. The modifications were higher chromium content, which improved corrosion resistance to high temperature hydrogen sulfide, and lower nickel content, which produced a duplex structure with improved resistance to stress corrosion cracking. This alloy has been in service for three years without any failures. A new British boiler and superheater steel has been announced (QJ). This low alloy steel contains 0.10 to 0.20% C, 1.5% Mn, 0.2 to 0.3% Mo, 0.2% Si, 0.01 to 0.05% Cb, and 0.010 to 0.01570 N. I t has good creep-rupture strength to 850°F and also good lowtemperature properties. Two new stainless steels suitable for pyrolysis and steammethane reformer furnace tubes have been reported. The first of these is a 0.2070 C, 25% Cr, 20y0 Ni steel which also contains about 0.35Y0 N ( 7 3 4 . The nitrogen addition increases the creep-rupture strength of this alloy considerably because it retards the coalescence of the carbides. The second alloy is a 0.24y0 C, 21% Cr, 2170 Ni, 1% Mn, 1% Ti, 0.01570 B cast steel ( 6 J ) . It also has excellent creep-rupture strength a t 1550 to 1650’F. Development of a series of new superplastic stainless steels has been announced by The International Nickel Co. (5J). A typical composition of these austenitic-ferritic microduplex alloys is 26y0 Cr, 6.570 Ni, 0.02% C, balance Fe. The alloys have excellent weldability, formability, corrosion resistance, and strengthespecially fatigue strength. The initial commercial applications of these materials are expected to be in areas where cold-rolled austenitic stainless steels are now used. VOL. 6 1
NO. 8 A U G U S T 1 9 6 9
45
New Manufacturing Techniques
T h e manufacture of stainless steels in a basic oxygen furnace using a hot blast cupola feed has been described (7K). The operation of this new unit is detailed. A new argon-oxygen process for refining stainless steels has been announced ( 8 K ) . T h e argon promotes carbon removal by lowering the partial pressure of carbon monoxide over the bath without appreciably oxidizing the chromium. This process, which permits the refining to be done in a different vessel from the melting for better control, produces excellent chromium recovery and allows the relatively inexpensive high carbon ferrochromium to be used as a source of chromium. Continuous casting of low carbon steel for tubing has been successful ( 3 K ) . Experiments with l1/2rCr Osteels were unsuccessful because of the high nonmetallic inclusion content of the resulting castings. Several new pipe and tube manufacturing techniques have been reported again this year. A review of the manufacture of welded steel pipe and tubing has been presented ( 7 4 K ) . T h e history and new developments in the butt, lap, electric resistance (ERW), high frequency, submerged arc, and induction welding processes are detailed. T h e production of finned tubes is also mentioned. A modern ERW pipe mill including sizing, finishing, and testing facilities has been described. Details of a new plant for the production of large diameter, spiral-welded pipe have been published ( 9 K ) . New equipment for the high frequency welding of low carbon, high carbon, and stainless steel tubing has been introduced ( 6 K ) . A continuous out-of-vacuum electron beam weld tube mill has been developed ( 7 5 K ) . Types 304 and 304L stainless steel tubes have been welded a t speeds of 40 to 80 ft/min on this mill. T o date, the mill has been used chiefly for specialty tube applications. T h e successful application of ultrasonic energy to the plug drawing of tubing has been reported ( Z K , 5 K ) . Die wear and friction are reduced by vibrating the plug at about 15 kc/sec. Surfaces and size tolerances are improved and may, in some instances, be equal to those obtained by rod drawing. A method of forming large-diameter heavy-wall welding fittings from centrifugally cast stainless steel tubes has been developed ( 7 3 K ) . These fittings are intended for refinery piping systems. Composite beams have been made by high-frequency resistance welding ( 4 K ) . This process is economical for the production of thick wide beams, tapered beams, and beams made of two or more alloys. Various techniques of metal forming with explosives have been reviewed ( 7 K ) . Shapes, dimensions, alloys, and economics are discussed. T h e use of overstressing techniques to reduce the risk of subsequent brittle fracture has been evaluated (IOK, I 7 K ) . This review of 110 references discusses the use of preloading as a means of mechanical stress relief where thermal treatment is not practical. T h e present applications of these techniques are outlined. Welding
New welding processes have been reviewed (4L, 7 L ) . The trend in welding today is to increased deposition rates and decreased heat input. T h e electroslag, plasma arc, electron beam, laser, friction, cold pressure, and ultrasonic welding processes are described ( 4 L ) . Internal bore welding, electroslag welding, and stainless steel strip cladding are also described ( 7 L ) . A survey of high-strength steel welding has been made ( 5 L ) . Most welding methods, including T I G hot wire and M I G fine wire (Narrow Gap), are shown. Filler metals are listed. Problems such as lack of toughness are discussed. Recommended procedures for welding large pressure vessels have been detailed (2L). T h e welding of stainless steels has been reviewed (7L, 73L). Welding methods include coated electrode, T I G , MIG, submerged arc, plasma arc, electron beam, and laser welding. Welding procedures for pressure vessel fabrication are included (7L). T h e current methods of joining light-wall stainless steel piping have been discussed (72L). T h e welding characteristics of the stainless steels have been evaluated (6L). The effects of oxidation, carburization, alloy additions, and contamination of the weld on weld quality and intended service are considered. Microstructures and properties of the welded joints are shown. A weld metal structure diagram has been developed for the chromium-manganese stainless steels (7015).This diagram is more accurate for these steels than the well-known Schaeffler diagram which was developed for the chromium-nickel stainless steels. Preferred filler metals for stainless steel and dissimilar metal welds have been tabulated (74L). 46
INDUSTRIAL AND E N G I N E E R I N G CHEMISTRY
New applications of electron beam welding ( T I L ) and cutting ( 9 L ) have been reported. Large-diameter pipe lines have been routinely welded with a portable electron beam welder (77L). Methods of welding clad steels have been summarized ( 3 L ) . Welding, preparation welding, postweld heat treatment, inspection, and testing are described. A new one-pass submerged-arc weld-overlay technique has been developed (8L). Satisfactory results are obtained through proper control of welding variables, especially welding speed. This method is more economical than the widely used two-pass overlay techniques.
REFERENCES
Materials Selection (14) Babakov, A. A., itietallooed. i Term. Obrabotka Metal., 1967 (lo), 43-50. (2A) Brickner, K . G., Metals Eng. Quart., 8 (2), 1-29 (1968). (3A) Briggs, A,, Brit. Chem. Eng., 13 (3), 369-71 (1968). (4A) Fischer, H. B., IND.ENO.CHEM.,60 ( 8 ) , 45-50 (1968). (5A) Hopkin, L. M. T., Progr. Appl. Mater. Res. 7 , 33-90 (1967). (6A) Irvine, K . J., Iron Steel Inst. (London), Puhl. No. 104, 1-10 (1967). (7A) Miller, R., Jr., Chem. Eng., 75 ( l o ) ,210, 212, 214 (1968). (8A) Parker, T. D., Metals Eng. Quart., 8 (Z), 47-66 (1968). Droht, 19 ( l ) , 1-7 (1968). (9A) Reich, W., (10A) Ruttmann W Krause, M., and Kremer, K . J., Iron Steel Inst. (London), Puhl. No. 97, $3-9”(1967). (11A) Samans, C. H., Chem. Eng., 75 (4), 150, 152, 154, 156, 158, 160 (1968). (12h) Schoefer, E. A.,Ind. Heating, 34 (101, 1917-19, 1922, 1924, 1926, 1928-1930 (1967). (13A) Sheldrick, M. G., Chem. Eng., 75 (24), 138-78 (1968). (14A) Sheppard, T . , and Brooks, M. G., Metallurgia, 16 (4561,145-51 (1967). (15A) Truman, J. E., Metals Mater., 2 (7), 208-16 (1968). Chemical a n d Petrochemical Industry (1B) Banfield, R . H., Anticorrosion Methods Materials, 15 (7), 5-10, 16 (1968). (ZB) Borzdyka, A. M., and Lanskaya, K . A., Metallooed. i Term. Obrabotka Metal., 1967 (lo), 50-7. (3B) Coulson, K . J., Chem. Process Eng., 49 (6), 97-101, 106 (1968). (4B) Edstrom, J. O., and Lofhlad, B., Werkstofe Korrosion, 18 (9), 771-7 (1967). (5B) Ginshurg, K . M., Chem. Process Eng., 49 ( 6 ) , 87-9 (1968). (GB) Hohjo, H., Kagaku Sochi, 9 (9), 48-57 (1967). (7B) Magnusson, L., Tiddskr.Kjemi. Bergvesen Met., 28 (4), 83-8 (1968). (8B) Spaehn, H., and Graefen, H., Techn. Mitt., 61 (3), 140-55 (1968). (9B) Swales, G. L., Ing. Quim., 12 (1341, 20, 22, 24, 28, 30, 32, 35-6, 38, 40, 42-9 (1967). (10B) Uhukata, K., and Shima, I., Kagaku Sochi, 10 ( 6 ) , 59-68 (1968). Specific Chemical Processes ( 1 0 Avery, R. E., and Valentine, H . L., Chem. Eng. Progr., 64 ( l ) , 89-92 (1968). (2C) Banks, W. P., Mater. Protect., 7 (31, 35-8 (1968). (3C) Blore, M. H. D., Can. Chem. Process, 5 2 (5), 80-3 (1968). (4C) Ciuffreda, A. R., and Hopkinson, B. E., Proc. API, Diu. Refining, 1968 (48), 208-44. ( 5 C ) Edstrom, J. O., and Lindh, G., Chem. AgeIndia, 18 ( l l ) , 779-88 (1967). (6C) Elmes, A. W., and Raymond, M. J. M., Brit. Patent 1,103,592(Feh. 21,1968). (7C) Fitzharris, J. J., and Bird, D. B., Muter. Protect., 7 ( O ) , 24-8 (1968). (8C) Fleischer, K . W., and Breckenridge, R. M., U. S. Patent 3,399,117 (Aug. 27, 1968). (9C) Gautier, R., Corrosion Troit. Prot. Finit., 15 (7), 342-3 (1967). (l0C) Gerbil’skii, E. I., and Riskin, I. V., Zashchita Metal., 4 (l),27-30 (1968). (11C) Klochkov .4. I. Emel’yanova, V. P., Koval, A. B., Dobrovol’skii, I. P., Kholoptsev, V’. P., akd Grigor’ev, N. P., Koks. Kkim., 1968 (6), 51-4. (12‘2) Kuzmak, E. M Karmazinov N. P. Kroshkin V. A . Ivanov, G. A , , 37-9. Durov, S. V., and Ry;kov, L. G., Kk;m. .Weft: Mashinostr:, 1968 (i), (13’2) Le Mounier, J., Entropie, 1967 (14), 87-93. (14C) Levin, I. A,, and Kil’chevskaya, T. E., Bor’ba Korror. Khim. Neft. Prom,, 1 9 6 1 (l), 180-9. (15C) Maunders, J. C., and Grant, A . J., Chem. Process. Eng., 49 (4), 70-1 (1968). (16C) Miller,R., Jr.,Chem. Eng., 75 (2), 182, 184, 186, 188 (1968). (17C) Perin Y u I. Valieva R . A Kuznetsova, G. E., and Dohronravov, V. A,, Kkim. ~ r o 43’(1i), A 930-1 ’(1967j.’ (18C) Ponomarenko V I. Medvedeva, N. M., and Kalashnikov, V. A,, Zaskckita Metal.,4 (1), 102-i (1968). (19C) Pouillard, E., Corrosion Trait. Prot. Finit., 16 (31, 108-12 (1968). (20C) Riggs, 0. L., Jr., and Banks, W-. P., Mater. Protect., 7 (S), 39-42 (1968). (21C) Rushton, W.E., Chem. Eng. Progr., 64 ( 5 ) , 68-70 (1968). (22’2) Schmidt, D., and Reichardt, H. D., Bergnkademie, 19 ( 9 ) , 536-9 (1967). (23C) Speed, D. W., Safety Air Ammonia Plants, 1967 (9), 46-7. (24C) Steensland, O., Allgem. Papier-Rundsch., 1968 (181, 506, 508-10. (25C) Todd, B., European Symp. Fresh Waterfrom Sea, Znd, Athens, 4 (49), Pt. 3, 12 pp. (1967). (26C) Verma, K . M., Ghosh, H., Gupta, M. P., Verma, S. C., and Roy, A . K., Technology (Sindri), 4 (4), 135-8 (1967). (27C) M’alton, N. H., Safety Air Ammonia Plants, 1967 (91, 73-7. (28C) Williams, E., and Leckie, H. P., Mater. Protect., 7 (7), 21-5 (1968). Specific Chemical Equipment (1D) Baralis, G., and Tangerini, I., Electrochim. Metal., 3 (l), 103-5 (1968). (2D) Gulyaev, V. N., Luzhnov, M. I., Kerimov, Yu. M., Tsybina, I. N., and Parfenova, T. N., Teploenerg., 14 (12), 32-6 (1967). (3D) Heller, J. J., Proc. API, Diu. Rejining, 1967 (47), 280-5.
(4D) Holmes, D. R., Corrosion Sci.,8 (E), 603-22 (1968). (5D) Kasai, T., Kuguku Kogyo, 19 (4), 384-91 (1968). (6D) Klapper, J. A., and Micek, W. A,, Proc. Amer. Power Conj., 1967 (27), 738-53. (7D) Masek, J.A., Chem. Eng., 75 (13), 215-29 (1968). (ED) Mendel, O., ibid., pp 255-6. (9D) Nicodemi, W., and Sinigaglia, D., Electrochim. Metul., 2 (3), 352-5 (1967). (10D) Ochiai, Y., Kugaku Kojo, 12 (Z), 21-6 (1968). (11D) Piehl, R . L., Proc. API, Diu. Refining, 1968, (481, 196-207. (12D) Rubin, F. L., Chem. Eng., 75 (E), 130-6 (1968). (13D) Saunders, E. A. D Thomas, S. N . G., and Horn, R., Chem. Process Eng., 49 (5), 75-77,81 (i968j: (14D) Spleiss, E., Metalurgia (Buchurest), 19 (lo), 567-71 (1967). (15D) Thielsch, H., ASM Tech. Rept. (C7-11.3), Pamphlet 29 pp (1967). (16D) Wright, F. W., Rev. Chim., 18 (7), 425-6 (1967). (17D) Zalesskaya, E . B., Bocharov, A. N., Medvedev, Yu. S., and Pupelis, V. N., Bor’ba Korror. Khim. Nefr. Prom., 1967 (l), 142-9. Boilera and Pressure Veasela (IE) Ames, W. C., and Lux, J. A., Proc. Amer. Power Conj., 1967 (29), 763-77.
(2E)Andrejew, L., Feill, A., and Polek, Z., Hutnik, 35 (5), 225-30 (1968). (3E) Bailey, T. L., Metul Progr., 94 (2), 77-8,80 (1968). (4E) Brown, T. D., and Ritchie, J., J.Inst. Fuel, 41 (331), 322-9 (1768). (5E) Chelius, J., Werkstofe Korrosion, 19 (4), 307-12 (1968). (6E) Chem. Eng., 75 (12), 122,124 (1768). (7E) Chernykh, N. P., Molchanova, V. D., and Zolotenin, G. G., Khim. Neft. Mushinostr., 1968 (Z), 22-4. (8E) Drake, P. F., and Lees, B., Erdoel Erdgas Z.,84 (5), 157-63 (1968). (7E) Gul aev, V. N., and Tsybina, I. N., Mefalloved. i Term. Obrabofka Mstul., 1968 (71 59-62. (10E) Harada, Y . , Tanaka, K., and Tokuda, M., Tech. Rev. Mitsubishi Heavy Ind., 5 (2),97-105 (1968). (11E) Huppertz, P. H., and Bihler, S., Tech. Ueberwachung, 8 (lo), 338-44 (1967). (12E) Ishihara, Y . , Bull. Jap. Petrol. Inst., 1968 (lo), 28-33. (13E) Lautzenheiser, G. E;, and Wylie, R . D., ASME Publ., 67 (PET-43) 5 pp., Pamphlet (1767). (14E) McClelland, G. D., Chem. Eng., 75 (ZO), 202-14 (1768). (15E) Mitsiibishi Heavy Industries, Ltd., Brit. Patent 1,092,855 (Nov. 29, 1967). (16E) Muroi, S., and Someno, M., Nippon Kinroku Gukkoi-Si, 32 (3), 276-82 (1968). (17E) . . Pierot., S.., A T I P (Ass. Tech. Ind. Paoet.). Rev.., 21 (2). . . , 51-66 (1967). . . (18E) Pilborough, L., Chem. Process Eng., 49 ( l ) , 80-4 (1968). (19E) Reid, W. T., Miller, P. D., and Krause, H . H., Jr., Prod, API, Diu. Refining, 1967 . 1471. 404-19. (20E) Sute, W. T., ASME Publ., 67 (PET-I), 8 pp., Pamphlet (1967). (21E) Thilakan, H. R., Lahiri, A. K., and Banerjee, T., N M L (Nutl. Met. Lub.) Tech. J., 9 (Z), 20-5 (1967). (22E) Whitman, G. D., Robinson, G. C., Jr., and Savolainen, A. W., U. S. Atomic Energy Commission, ORNL-NSIC-21,675 p p (1967). (23E) Witkin,D. E., Chem. Eng., 75 (18), 124, 126, 128, 130 (1968). (24E) Witschakowski, W., Chem. Process Eng., 49 ( l ) , 63-6, 70 (1968).
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Corrosion Resistance (1F) Fontana, M. G., and Greene, N. D., “Corrosion Engineering,” 391 pp., McGraw-Hill, New York, N. Y. (1967). (2F) Rabald, E., “Corrosion Guide,” 900 pp, Elsevier, Amsterdam, (1968). (3F) Ross, T. K., Brit. CorrosionJ., 2 (4), 131-40 (1967). (4F) Slama, V., and Bartonicek, R., Chem. Prum., 18 (2), 90-3 (1968). (5F) Sorell, G., Chem. Eng., 75 (16), 162,164, 166-8,170 (1968). (6F) Stanners, J. F., Bonner, P. E., Drewitt, R., Kilcullen, M. B., and Lewis, J. A,, Brit. Corrosion J., 2 (6), 242-9 (1767). (7F) Wilson, C. L and Oates, J. A “Corrosion and the Maintenance Engineer,” 196 pp, Hart PUG., New York, N. ?. (1968). Specific Corrosion Data (1G) Armijo, J. S.,Corrosion, 24 (l), 24-30 (1768). ( 2 G ) Baecker, L., Usine Nouvelle, pp 238-41, 243, 246, 248, November 1967 (SUPPl). (3G) Biefer, G. J., Can. Dept. Energy, Mines Resour., Mines Br., Tech. Bull., No. 87, 19 p p (1967). (4G) Bilek, P., and Mechura, J., Werkstofe Korrosion, 19 (4), 298-301 (1968). (5G) Briggs, C. W., ASTM Spec. Tech. Publ., No. 435, 271-84 (1968). (6G) Buttinelli, D., and Memmi, M., Ann. Chim. (Rome),58 (6), 615-24 (1968). (7G) Cihal, V., and Lehka, N., HutnickeListy, 23 (5), 338-51 (1968). (8G) Demo, J. J., Corrosion, 24 (5), 137-49 (1968). (7G) Desestret, A., Corrosion Truit. Plot. Finit., 15 (6), 281-7 (1967). (10G) Desestret, A., ibid., 16 (l), 14-9 (1968). (11G) Dubskikh, V. Ya., Chemezova, S . A., and Derevyankin, V. I., Khim. Neft. Marhtnostr., (3), 27-8 (1968). (12G) Gautier, R., Corrosion Trait. Plot. Finit., 15 (7), 342-3 (1967). (13G) Holden, H. A., Chem. Process Eng., 49 (61, 75-7 (1968). (14G) Kijima, S., Kugaku Kojo, 11 @),53-61 (1967). (15G) Konstantinova, E. V Seminova, L. S and D’yakov, A. A., Proceed. Int. Symp. Wuter Desalinafion, F&t, Washington, D: C., (Z),549-59 (1967). (16G) Kuzub, V. S., Mukhlya, S. Yu., Kossyi, G. G., and Dolotova, T. S., Ukr Khim. Zh., 34 (2), 212-4 (1768). (17G) Marchesini, L., and Scarinci, G., Tec. Ztul., 32 (9), 575-85 (1967). (18G) Marchesini, L., and Scarinci, G., ibid., 33 (l-z), 31-42 (1968). (17G) Marchesini, L., and Scarinci, G., ibid., (6), p p 429-37. (20G) Mason, J. F., Jr., Metuls Ens. Quurt., 8 (2), 67-80 (1968). (21G) Morris, L. A,, ibid., pp 30-47. (22G) Pos saeva, L. I., Babakov, A. A., and Petrovskaya, V. A., S6. Tr. Trent. Nuuchn.-hed. Inst. Chernot Met., No. 52.78-80 (1967). (23G) Pourbaix, M., and Pourbaix, A., Cebelcor Ruppt. Tech., No. 141, 1-16 (1967). (24G) Romanoff, M., J . Amer. Water Works Assoc., 60 (6), 645-55 (1968).
(25G) Sears, E. C., Mater. Protect., 7 (lo), 33-6 (1968). (26G) Sugiyama, I. T., and Inagaki, S., Denki Seiko, 38 (5), 283-73 (1967). (27G) Takasaka, Y., KoutsuGaru, 4 (5), 239-50 (1967). (28G) Vorob’eva, M. A., and Klinov, I. Ya., Bor’bu Korror. Khim. Neft. Prom., 1967 (l), 168-79.
Stress Corrosion Cracking (1H) Benson, R. B., Jr., Dann, R. K., and Roberts, L. W., Jr., Trans. Met. SOC. A I M E , 242 (lo), 2199-205 (1968). (2H) Bogol ubskii, S . D., Alekseev, V. I., Ushakov, I. S., and Shvartsman, L. A,, Zh. Fir. C ? k , 42 (3), 609-14 (1968). (3H) Bond, A. P., and Dundas, H. J., Corrosion, 24 (lo), 344-52 (1968). (4H) Capasso, C., and Bruno, R., Rass. Chim., 20 (3), 93-105 (1 968). (5H) Denhard, E. E., Jr., A G A R D Conf.Proc., 1967 (18), V-1 t o V-38. (6H) Eckel, J. F., and Cox, T. B., Corrosion, 24 (7), 218-22 (1768). (7H) Fletcher, E. E., and Elsea, A. R., Bntfelle Tech. Rea., 16 (12), 10-5 (1967). (8H) Fontana, M. G., AGARD Conf. Proc., 1967 (18), 1-1 to 1-22. (9H) Gerasimov, V. I., and Ryabchenkov, A. V., Zushchitu Metal., 4 (4), 441-4 (1968). (10H) Gerasimov, V. V., Gromova, A . I., and Sabinin, A. A., Teploenerg., 15 (6), 40-1 (1968). (11H) Horikawa, K., Tetsu To Hagane, 54 (5), 610-31 (1968). (12H) Horikawa, K., Kihara, H., Watanabe, M., and Inagaki, M., Nippon Kokun Tech. Rept. Overreus, 8, 35-50 (1768). (13H) Kawamura, T., and Oka, E., Sekiyu To Sekiyu Kaguku, 11 (6), 19-23 (1967). (14H) Kohut, G. B., and McGuire, W. J., Mater. Protect., 7 (6), 17-22 (1968). (15H) Lerner, R., Corros. Trait. Prol.Finit., 16 (4), 177-86 (1968). (16H) Popov, K. V., and Nechai, E. P., Fir.-Khim. Mekhan. Moterialnu, 3 (6), 631-50 (1967). (17H) Rogers, H . C., Science, 159 (3817), 1057-64 (1968). (18H) Sachs, K., and Morgan, A., J . Iron Steel Inst. (London), 206 (Pt. 4), 357-62 (1968). (19H) Saga, T., Tobe, S., and Sato, M., Kinroku Hyomen Gijutsu, 19 (6), 230-5 (1968). @OH) Snape, E., Corrosion, 24 (91, 261-83 (1968). New Alloys (1J) Bourrat, J., Demestre, J., Mercier, A., and Remy, G., Rev. Met., 64 (12), 1095-114 (1767). (25) Chem. E y . News, 46 (14), 60-2 (1968). (35) Clark, E. E., Murray, J. D., and Llewellyn, D. T., Iron Steel Inst. (London), Publ. No. 104, 188-200 (1967). (45) Engineering (London), 205 (5328), 831 (1968). (5J) Gibson, R . C., Hayden, H. W., and Brophy, J. H., ASM Truns. Quart., 61 (1) 85-93 (1968). (6J) Kirkby, H. W., and Hardwick, D., Brit. Patent 1,123,971 (Aug. 14, 1968). (75) Mackenzie, I. M., Met& Mater., 2 (7), 187-94 (1968). (SJ) Metallurgia, 7 7 (464), 237-8 (1768). (95) Murray, J. D., Brit. Patent 1,101,193 (January 31, 1968). (1OJ) Prescott, G. R., and Heller, J. J., Muter. Protect., 7 (3), 42-4 (1968). (11J) Scheepens, C. P., Constructiemateriulen, 1 (IO), 16-21 (1967). (125) Schoeller-Bleckmann Stahlwerke A.G., Brit. Patent 1,097,004 (Dec 29, 1967). (13J) Tanaka, R., and Suzuki, I., Tetsu To Hapane, 54 (41, 489-97 (1768). (14J) Tavadze, L. F., Tavadze, F. N., Mandzhgaladze, S. N., and Ramazashvili, D. R., Zashchita Metal., 3 (5), 610-13 (1967). New Manufacturing Techniques (1K) De la Calle Estrada, A., An. Mec. Elect., 44 (5), 229-307, 365-74 (1967). (2K) Engineer, 224 (5826), 395 (1967). (3K) Holden, C . , and Vincent, D., Open Hearth Proc., 50, 53-9 (1967). (4K) Iron Age, 202 (26), 35-7 (1768). (5K) Jones, J. B., Metal Progr., 93 (51, 103-7 (1968). (6K) Lewis, G. E., Welding, 36 (l), 22-5 (1968). (7K) Loutzenhiser, R . H., Meyer, H. W., and Aukrust, E., Iron Steel Eng., 45 ( l ) , 124-8 (1968). (8K) Malim, T. H., Iron Age, 202 ( l ) , 53-6 (1968). (7K) Metals Muter., 2 (Z), 34-5 (1968). (IOK) Nichols, R. W., Brit. Welding J., 15 (11, 21-42 (1968). (11K) Nichols, R . W., rbid., 15 (Z), 75-84 (1968). (12K) Rode, H.,Iron Steel Eng., 44 (lo), 102-8 (1967). (13K) Tollivcr, J. D., Proc. API, Diu. Rejning, 1967 (47), 271-9. (14K) Veall, C.E., Donaldson, J., and Woodward, D. H., Brit. Welding J.,15 (4), 170-7 (1968). (15K) Welding Engr., 52 (12), 42-3 (1767).
Welding (1L) Banks, B., Welding, 36 (5), 164-71 (1768). (2L) Brit. Welding J., 15 (7), 326-32 (1768). (3L) Ellis, D., Welding, 95 (9), 359-64 (1767). (4L) Fletcher, M. J., Can. Mach. Metalworking, 79 (5), 68-70 (1968). (5L) Irving, R. R., Iron Age, 202 (IO), 61-8 (1968). (6L) Linnert, G. E., Met& Eng. Quart., 7 (41, 1-15 (1967). (7L) McDowall, I., Chem. Process Eng., 49 (5), 82-4 (1968). (EL) Mueller, R., and Nickl, J., Schweisstechntk, 17 ( 8 ) , 349-52 (1967). (9L) Pahlitzsch, G., and Visser, A., C I R P Ann. Int. Inst. Prod. Eng. Res., 13 (2), 14755 (1966). (1OL) Razikov, M. I., Kocheva, G. N., and Tolstykh, L. G., Automat. Svarka, 21 (4), 1-5 (1968). (11L) Schollhammer, F. R., Pipe Line Ind., 28 (3), 53-6, 57-61 (1968). (12L) Sosnin, H. A., Welding J., 46 (lo), 844-9 (1967). (13L) Sullivan, R. P., Metals Eng. Quart., 7 (4), 16-41 (1967). (14L) Tool Manuj. Eng., 59 (4), 92-3 (1967).
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