October 22, 1971
THE CORROSIVE BEHAVIOR OF 304 AND 304L STAINLESS STEEL IN GASEOUS ENVIRONMENTS:
AN ANNOTATED BIBLIOGRAPHY
Linden M. Sreward Jerry L. Stakebake
DOW CHEMICAL U.S.A. ROCKY FLATS DIVISION P. 0. BOX 888 GOLDEN, COLORADO 80401
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THE CORROSIVE BEHAVIOR OF 304 AND 304L STAINLESS STEEL IN GASEOUS ENVIRONMENTS:
AN ANNOTATED BIBLIOGRAPHY
Linden M. Steward . Jerry L. Stakebake
- - . . NOTICE .i This report was prepared as an account of work sponsored by the United States Government. Neither the Unitod States nor the Unlted Scaces Atomic Energy ' Commission, nor any of 'their employees, nor any of' their'.contractors,'subcontractors,or their employees, makes any warranty, express or implied, or assumes any '
, , 'legal liability of responsibility for the accuracy, com- pleteness or usef~ilness',ofany information, apparatus, product or process disclosed, or represents that its use would not infringe privately.owned rights.
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DOW CHEMICAL U.S.A. ROCKY FLATS DIVISION P. 0. BOX 888 GOLDEN, COLORADO 80401
Prepared under Contract AT(29-1)-1106 for the Albuquerque Operations Office U: 5. Atomic Energy Commission DISIRlBUTIOM OF THIS DOCUMENT IS UWIMIlf h CONTENTS
Abstract ...... : ...... 1 Introduction ...... 1 Summary of Reactions ...... 2 Hydrogen ...... 2 Steam ...... 2 Oxygen ...... 2 Hydrogen Sulfide and Hydrogen Chloride ...... 2 1 Carbon Monoxide and Carbon Dioxide ...... 2 Other Environments ...... 2 Abstracts ...... 2 Section A: Abstracts Concerning the Corrosion of 304L ..... : ...... 3 Section B: Abstracts Concerning Both 304 and 304L ...... 4
Section C. . Abstracts Concerning the Corrosion of 304 ...... 4 Section D: General Abstracts on. Stainless SteelCorrosion ...... 7 Author Index and Abstract Numbers ...... !5 THE CORROSIVE BEHAVIOR OF 304 AND 304L STAINLESS STEEL IN GASEOUS ENVIRONMENTS: AN ANNOTATED BIBLIOGRAPHY Linden M. Steward and Jerry L. Stakebake
Abstract. The available literature on the gaseous corrosion Like all steels classified generally as 18-8 stainless of types 304 and 304L stainless steel has been reviewed. (-18% Cr - 8% Ni), 304 and 304L are ductile, tough, and This report summarizes the results of some typical chemical highly corrosion resistant in most atmospheres.(28y29) reactions between 304 and 304L and various gases. Refer- When allowed to oxidize in air at temperatures up to ences to the general area of stress corrosion were not 200°C,-they form an invisible surface oxide film (oxidation included in this survey. Included are abstracts from 72 at temperatures above 200"~usually produces a visible references. oxide scale).(28) It is this protective film which gives the stainless steel surface its passivity and therefore its corrosion resistance at low temperatures.(2s129) (At higher tempera- tures passivity may be due to either a passivating film INTRODUCTION formation, an adsorbed oxygen monolayer, or a combina- tion of both.) Among the many steels utilized in the nuclear industry, AISI 304 and 304L are probably the most common. Stainless steel oxidizes in a layered structure (28129,38)with While these materials may generally be considered inert for that layer closest to the surface usually composed of either most low temperature applications, it is conceivable that spinel FeCr2 O4 and/or Cr2 03, with up to 90% CrZO3 they may corrode sufficiently to pose a significant problem present on highly polished surfaces.(28) Both of these in some of the specific uses of these steels, particularly structures are highly protective and, in general, the more 304L. To better understand the corrosion behavior of uniform the surface the more protkctive this film 304L steel in gaseous environments the literature on this become^.(^'*^^) The remaining oxides formed in atmo- subject has been surveyed and the results are included in spheric conditions under 500°C include Fe304 and this report in the form of an annotated bibliography and Fez O3 with Mn2 07,NiO, and Si02 usually additional summaries of typical reactions. Throughout present.(28137253*57,67)At higher temperatures, i.e., this report the term "corrosion" refers only to chemical >600°C, ferrous oxide often becomes the major iron- reactions in gaseous atmospheres and should not be confused oxide:c~nstituent.(~') with reactions in liquid environments nor with the much broader field of stress corrosion. Corrosion is usually enhanced by any factor that produces ,.: 1 : 1.1
partial or complete removal of the passivating oxide film I. .:.. without allowing it to reform.(28y29)Therefore,. any 304L is an austenitic nickel-chromium stainless steel. It chemical, thermal, or mechanical treatment, which accom- differs from AISI 304 only in carbon content, 0.03% plishes this film removal or breakdown will usually result maximum for 304L compared to a maximum of 0.08% for in increased corrosion.(2s) 304. Roth steals contain a maximum of 2%manganese, 0.045% phosphorus, 0.03% sulfur, 1% silicon, 18-20% Small temperature changes do not appreciably affect the chromium, and 8-12% nickel. The corrosion behavior of oxidation rate of stainless steels. Moisture, however, does both steels is essentially the same for low temperature increase the rate of corrosion.(2a) For example, stainless applications. At higher temperatures, however, the lower steel samples exposed to oxygen with a relative humidity carbon content of 304L reduces its susceptibility to inter- of 80% at 2s°C developed oxide films 1 '/, times as thick granular attack which is associated with chromium deple- as those produced in the same time in dry oxygen.(29) tion by chromium-carbide precipitation. This would occur Carbon dioxide disrupts the protective oxide layer and thus in the metal adjacent to a or during high increases corrosion by or, secondarily, by temperature oxidation,('') i.e., where microstructurally other means such as carburization.(" ) Ionizing radiation selective corrosion is a prime factor. Corrosion experiments has also been shown to increase corrosion in some involving four steels in superheated steam all showed the instances.(32) When small amounts of SOz are present in low carbon steels to be more resistant to intergranular oxygen, the rate of oxidation may increase due to the corro~ion.('~) breakdown of the first-formed protective film, providing the SO2 reaches the metal surface. If either the spinel or *Note: The numbers in parenthesis refer to abstract numbers in Crz03 film has completely formed, there is little or no (Itis report. ratc acccleration at normal temperatures.(29) SUMMARY OF REACTIONS third period of slow oxidation.(38) The major oxidation products of 304L in air at temperatures of 1100 to 1360"~ Literature concerning the corrosion behavior of 304 and were Fe304 and Fe203 wit11 Cr203~OUII~ at Iht: rrlrfal- 304L stainless steels in gaseous environments is rather oxide interface.(6) limited. Most of the work has been limited to corrosion in either carbon dioxide or steam. A summary of the published work pertaining to reactions in these as well as Hydrogen Sulfide Hydrogen other gases follows. Stainless steels in dry hydrogen sulfide begin to corrode at about 360'~. In some cases the presence of water vapor slowed down the rate. At high temperatures, steels and steel'alloys corrode faster in dry chloride or C12 gas than in dry H2S, whereas in the presence of water vapor this is No specific information was found for 304L. However, reversed.(39) six steels, including 304, were subjected to He &th small concentrations of H2 at temperatures of 649 - 760O~(~') and 899 - 1010"~.('~)None ofthe materials showed a Carbon Monoxide large change in mechanical properties at 649'~,and all and Carbun 6ioXlde(4, 7,lQ,l3>71,"0,41943,"014%fQ, C!,$e) except type 321H showed only moderate changes at 760'~. The major corrosion process appeared to be oxidation resulting from oxygen impurities. 3Lail~lesssteels arrd C02 ale appalerltly lll~ulrlpalilrl~at elevated with the cor;osion rate following a'parabolic relationship for all types of steel.(" A typical experiment resulted in penetrations of 0.01-0.04 mml 20 years at 400°C, 0.1-0.4 mrn120 years at 500°C, and A variety of tests have been conducted on stainless steels about 20 mml2O years at 600'~.(~')Although protective in steam and superheated steam in'connection with their oxide coatings can be formed in C02 and CO environ- applicability for use in nuclear reactors. At lower tem- ments up to 500°c, they often lose their protective peratures and pressures, e.g., 265OC and 750 psi, no character, especially at more elevated temperatures.(42) detectable damage occurred.(36) ow ever, steam under pressures of about 1000 psi at 500-700°C attacks some The corrosion of stainless steel by C02 is different from steels i~~ter~ranularl~;(~~)the degree of attack being the corrosion by air or oxygen because of secondary carburi- definitely related to grain size(') and carbon content('') zation reactions in addition to oxidation.(4~'0~s') for 18-8 steels. Work hardening several tens of microns deep is necessary to ensure good, long-term behavior of a 304 in superheated steam at 500'~.('~)'Ihe surface Other Environments oxide in this temperature range is still of the spinel type.(') See attached abstracts, especially 11, 15,22,23,30,32, At higher temperatures, e.g., >lOOO°C, the oxidation rate 45, and 52. of 304L stainless is approximately 1000 times as great in steam as in oxygen at the same temperatures.(6s24)This is probably due to excess Cr203 formation.(24) Both 304 and 304L suffered severe intergranular attack in tem- ABSTRACTS peratures above 1000~~in steam and superheated steam,(6*'0*19)and instances of transgranular attack were This section is devoted to abstracts related to the corrosion also noted.(27) of stainless steels, particularly 304 and 304L. The abstracts are divided into the following categories:
A. Abstracts concerning the corrosion of 304L. Studies,at 1050'C show that the oxidation of Cr-Ni steels is characterized by an initially slow rate following a para- B. Abstracts concerning both 304 and 304L. bolic law. The fdm thus formed remains protective for a period of time, followed by a period of rapid oxidation C. Abstracts concerning corrosion of 304. which continues until Fe is eliminated from the chromium depleted layer. This second period is then followed by a D. General abstracts of papers on stainless steel corrosion. SECTION A 4 Abstracts Concerning the Corrosion of 304L THE EFFECT OF LOCALIZED CARBURIZATION ON THE CORROSION RESISTANCE OF STAINLESS 1 STEEL PIPE AND TUBING. William L. Walker INTERIM SUMMARY OF WORK APPLICABLE TO (General Electric Co. Hanford Atomic Products Opera- ECC ON PHYSICOCHEMICAL STUDIES OF CLAR tion, Richland, Wash.) USAEC Report (HW-51267) URANIUM DIOXIDE UNDER REACTOR ACCIDENT (1957). CONDITIONS, James Fred White (Missile and Space Three smalldiameter 304L stainless steel pipes which Div., Gen. Elec. Co., Cincinnati, Ohio) USAEC Report failed the Huey test were examined. It was found that (GEM-61 9) (1 968). the greater weight loss occurred inside the tube, and high corrosion rates were observed until the carburized Physicochemical studies of clad U02 under reactor layer was removed. This layer is said to have resulted accident conditions are described, and studies on the from incomplete cleaning prior to heat treatment. behavior of Zircaloy- and 304L SS-clad U02 fuel elements in steam and steam plus air above 1000' are 5 discussed. These studies are directed to the behavior STUDIES OF STEEL CORROSION IN HIGH TEM- of these fuel elements and associated reactor core PERATURE WATER AND STEAM, Quarterly Report materials under a loss-of-coolant core meltdown incident. No. 16, July 1 - September 30, 1966 (Societe d'Etudes, Experimental work emphasized studies on the kinetics de Recherches et d'Applications pour l'Industrie, of oxidation of U02 to 1830'; studies of the steam Brussels, Belgium) (EURAEC-1744) (1 966). and air oxidation kinetics of Zircaloy-4 to 1800'; and studies of the steam and air oxidation kinetics of 304L The study of the recrystallization conditions of various SS to 1375'. grades of milled stainless steels was continued. It was found that Uranus 30 steel offers good behavior under 2 oxidation, after surface treatment, at temperatures at EFFECTS OF EXPOSURE TO SUPERHEAT- which standard 18-10 steels tend to deteriorate. The OXYGENATED STEAM OF 550'~(1022'~) AND study of grain size, with or without prior selective 1000 TO 3000 PSI PRESSURE UPON IRON AND oxidation treatment, was initiated on various grades of NICKEL BASE ALLOYS, H. J. Pessl (General Electric stainless steels. The initial results, for oxidation pre- Co. Hanford Atomic Products Operation, Richland, treatment at 800°c, indicate definite influence of the Wash.) (TID-7674) p. 16. grain size under these conditions. The effect is quan- titatively inadequate; however, long-duration tests in Results of general corrosion tests of nickel and iron superheated steam at 500'~on AISl 304L steel show alloys in superheated steam are presented. Results are that the work-hardening depth obtained by grinding is given for types 304L, 406,430,446, and 17-4 PH insufficient to quarantee satisfactory steel behavior. stainless steels, Hastelloy N and X, Inconel X, Incoloy, Tests in superheated steam at 500'~with 20 ppm oxy- aluminum-chromium-iron alloys with and without gen added do not show any weight differences from yttrium, and PDRL-102. The samples were exposed the tests carried out without oxygen. In thc tcsts with 100 days in oxygenated steam (3 to 4 ppm oxygen) oxygen added, the oxide skin formed on a surface at 550'~and 3000 psi. The samples were cathodically work-hardened 304 steel remains of the spinel type. descaled in molten electrolyte of 60 wt% sodium hydroxide and 30 wt% sodium carbonate at 560'~. 6 OXIDATION OF 304L STAINLESS STEEL BY STEAM 3 AND BY AIR, J. T. Bittcl, L. H. Sjodahl, and J. F. CORROSION OF STAINLESS STEELS AND ALLOYS. White, (General Electric Co., Cincinnati), Corrosion, 25, PART 1. STAINLESS STEELS: EUROCHEMIC 7-14 (1969). CORROSION TESTS (EIR-37) PART 11. ALLOYS FOR Oxidation of 304L stainless steel was measured in steam HEAD-END EQUIPMENT: SURVEY OF AVAILABLE and in air at 1000 to I 37s0c using a thermogravimetric INFORMATION (EIR-39). 0. Jenne (European technique. This temperature range is of interest in the Company for the Chemical Processing of Irradiated analysis of a reactor loss-of-coolant accident. Experi- Fucki, Mol, Belgium) (NP-9807) (1960). ments in steam showed initial linear weight gain with Results of a series of corrosion tests conducted to aid time for the first 6 to 28 minutes, followed by parabolic in selecting stainless steel for general radioactive service rate behavior. The linear reaction rate constant W/t was in the Eurochemic plant are presented. Summaries.of found to 1.I X 10' exp (-44, 350/RT) while the para- mean corrosion values obtained in all tests are presented bolic constant w2/t was found to be 2.4 X 1 012 exp along with results of individual tests. Results indicate (-84,30O/RT), where T is in OK and W is in mg/cm2 that 304L stainless steel and Ti-stabilized type 321 and t is in sec. The parabolic rate controlling process is steels are generally.superior. Ni-o-nel and Hastelloy F diffusion through an Fe-NiCr spinel layer observed in were compared for use in head-end equipment. the inner layer of the scale. The oxidation of 304L stainless steel by air from 1 100 to 1360'~was slow Natl. Res. Inst. Metals, Tokyo), Proc. Mem. Lect. Meet. compared with the oxidation by steam in this same tem- Ann. Found. Nut. Res. Inst. Metals, loth, Tokyo (1966) perature range, parabolic rates being lower than those in pp. 183-4. steam by a factor of -lo3. I The corrosion of four steels, AISI 304, 304L, 3 16, and Although x-ray diffraction observed Fe304 (major) 347 was studied. Corrosion rates were approximately and Fez O3 (minor) on the surface of the coatings 3 X lo-' mm/yr. for all four and were independent of formed in air at temperatures of 1360'~and below, the water flow rate. In the presence of Cl- the 31 6 Crz O3 was found at the metal-oxide interface. The steel showed greater stress corrosion resistance. low rates in air thus reflect the formation of a protec- tive Cr203. film. The rate in air at 1375'~is 10 exceptionally rapid compared with those at the lower STEAM CORROSION-EROSION TESTS ON STAIN- temperatures possibly because of the Fe-FeO liquidus STEELS. C. R. Bergen (Allis-Chalmers Mfg. Co., at 1370'~. Milwaukee) (TID-7674) pp. 4-8 Out-of-pile corrosion-erosion tests on 304, 304L, 3 16, 7 and 31 6L stainless steels in oxygenated-saturated and CLADDING & STRUCTURAL MATERIALS. Reactor oupcrheatcd steam were performed. All steels suffered Muter, 11, 226-52 (Winter 1968-69) Corrosive Effects son~cJcgree of intergranular attack. The net release on Type 304 SS at High Temperatures; COz Corrosive was insignificant for the low carbon steels but was up Effects and Radiation Effects on Stainless Steel; Oxi- to 60 mg/cm2 per 1000 hours for type 304 stainless dation of Type 304L by. High. Temperature Air and steel, Steam.
SECTION B Abstracts Concerning Both 304 and 304L SECTION C Abstracts Concerning the Corrosion of 304 8 CORROSION BEHAVIOR OF STAINLESS STEEL IN 11 HIGH-TEMPERATURE WATER AND STEAM, ARMY GAS-COOLED REACTOR SYSTEMS PRO- Tatsuo Maekawa and Masaru Kagawa (Mitsubishi Atomic GR.AM. EFFECTS OF GAS CORROSION AND Power Industries, Inc., Omiya, Japan), Nippon Kinzoku AGING ON ML-1 TURBINE ALLOYS, B. E. Farwell Cakkaishi, 31, 1213-19 (1967) (In Japanese). and J. S. Brunhouse (Aerojet-General Nucleonics, San The corrosion behaviors of AISI 304 and 304L stainless Ramon, Calif.) (IDO-28591) (1962). steels were studied to clarify the effects of temperature, Gas corrosion resistance and changes in mechanical surface finish, and dissolved oxygen in high-temperature properties of alloys to bc used in the ML-1 gas turbincs water and superheated steam. In degassed water, the are evaluated. The alloys were subjected to anticipated steels indicated a maximum corrosion rate between maximum operating conditions in three coolants pro- 250 and 350°c, and the corrosion rate was affected posed for ML-I operation: reference gas (99.5 vol% largely by the surface finish. In aerated water, the nitrogen + 0.5 vol% oxygen), air, and nitrogen. The corrosion rate was not so much affected by the cor- tests revealed that corrosion of Inconel, Inconel 7 13C, rosion temperature and surface finish. In superheated Incoloy 901, and Type 347 stainless steel was negligikle -steam, the corrosion rate increased with increasing in all coolants after exposure for 5000 hours at 1300 F; temperature and was affected markedly by the surface corrosion of Type 304 stainless steel (used for piping finish at high temperatures. The corrosion films pro- and tubing only) was negligible after 5000 hours at duced in degassed water and in steam consisted of 900'~. Oxidation of Type 422 stainless steel at 1200'~ magnetite and chromite, and the chromite content in oxidizing atmospheres was significant; however, as increased with increasing temperature, whereas those 1200'~is higher than design conditions ( 1 OOO'F), it is produced in aerated water consisted of yFez03. The believed that serious oxidation will not occur during 7 a phase transformed from the phase by cold-working operation. Aging reduced room temperature ductility or surface abrading decreased the corrosion resistance in of Incontl 7 13C and N-155 (Multin~etAlloy) after degassed water, but it greatly increased the corrosion 5000 hours at 1300'~. resistance in superheated steam.
12 9 EFFECT OF C02 ON THE STRENGTH AND EVALUATION OF CORROSION RESISTANCE OF DUCTILITY OF TYPE 304 STAINLESS STEEL AT AUSTENITIC STAINLESS STEELS FOR WATER ELEVATED TEMPERATURES, W. R. Martin and H. E. COOLED POWER REACTORS, Goro Ito, Yoshihika McCoy, Jr. (Oak Ridge National Lab., Tenn.) (ORNL- Shimizu, and Tadao lshihara (Corrosion Res. Div., TM-339) (1962). The mechanisms by which the carbon dioxide coolant Stainless steels were much less severely attacked by zinc affects the strength properties of type 304 stainless steelo vapor than by molten zinc systems. To determine the were investigated in the range 1300 to 1700'~(704-927 C). applicability of stainless steels for equipment items, Creep- and stress-rupture results obtained on the sheet which would be exposed only to zinc vapor, the materials in wet and dry C02 and argon are compared. corrosion resistance of several stainless steels to zinc The effect of annealing C02 on the tensile strength vapor was investigated in 500-hr exposures at 900~~. Two austenitic stainless steels, Types 304 and 347, ductility was also investigated. The question of whether ' the strengthening observed in C02 was due to oxidation suffered severe intergranular attack. Loss of nickel from or carburization was determined. Experiments on the these steels and microprobe analyses indicated the effect of various partial pressures of oxygen in argon probable formation of low melting zinc-rich phases. showed that the creep rate was minimum at approxi- Good resistance to attack by zinc vapor, as determined mately 10 ppm. The creep rate of C02 at equivalent by metallographic examination and physical testing, was stress and temperature was lower by a factor of 3 than exhibited by Type 405 stainless steel, a ferritic steel. the minimum rate observed in oxygen. Chemical Type 440C stainless steel, a martensitic steel, although analyses, metallography, and experiments with carbon suffering considerable loss in weight, was not structurally showed that carburization occurred in pure flowing weakened. C02 in thc tcmpcrature range studied. Prom this evidence it was concluded that the strengthening ob- 16 served in C02 was primarily due to carburization. STUDIES OF STEEL CORROSION IN HIGH TEM- The creep- and tensile-fracture strains were adversely PERATURE WATER AND STEAM, Quarterly Report affected by exposure to C02, with the magnitude of No. 7, January 1-March 31, 1964 (Societe d'Etudes, de the effect dependent on the time and temperature of Recherches et d'Applications pour I'Industrie, Brussels) exposure. (EURAEC-1047) (1964).
13 The static corrosion tests on stainless steel AISI 304 in CORROSION OF STAINLESS STEEL IN SUPER- high-temperature water and steam were continued in two HEATED STEAM, W. E. Ruther (Argonne National directions: on the one hand, research into the interaction Lab., Ill.) (TID-7674) pp. 8-10. of surface state, temperature, and physical state of the water; and on the other hand, research into the surface The effect surface preparation has on corrosion of type state characteristic factor, the influence of which is 304 stainless steel was investigated. A disturbed surface predominant in terms of the oxidation conditions. layer improves corrosion resistance. One way to effect this layer is cold working. A dynamic corrosion test 17 facility is being used to measure the corrosion charac- THE RELATIONSHIP OF NITROGEN CONTENT OF teristics of types 304 and 406 stainless steels. AUSTENITIC STAINLESS STEELS TO STRESS CORROSION, Quarterly Report No. 438-9, July 1- 14 September 30, 1966. Thomas B. Cox (Virginia Poly- EXPOSURE OF HTGR CANDIDATE CORE PLATE technic Inst., Blacksburg Dept. of Metals and Ceramic AND THERMAL INSULATION MATERIALS TO Engineering) (EURAEC-1755). IMPURE HELIUM AT 1650~~to 1850'~ FOR 3000 HOURS, J. W. Wunderlich and N. E. Baker (Gen. As part of an investigation to determine relationship Dynamics Corp., San Diego, Calif.) USAEC Report between N content of austenitic stainless steels and (CAMD-7377) (1 966). susceptibility to stress-corrosion cracking, experiments were conducted in which the solubility of N2 in AISI The following materials were exposed in He containing Types 304 and 308 stainless steel wires was determined. 3000 pplrl. CO and H at 1650 and 1850~~:Rene 41, Inconel X, Hastelloy X, 304 stainless steel, 430 stainless 18 steel, and lr~coloy800. Changes in mechanical prop INFLUENCE OF NICKEL ON INTERGRANULAR erties and microstructures were evaluated after 500 and CORROSION OF 18% CHROMIUM STE'ELS, J. R. Upp 1500 hrs. exposure of the above materials, and after (Wright-Patterson Air Force Base, Ohio) and F. H. Beck 3000 hrs. for 430 stainless steel and Hastelloy X. The and M. G. Fontana (Ohio State Univ., Columbus) results show that 430 stainless steel is the best choice Trans. Am. Soc. Metals, 759-72 (1958). as metallic thcrmal insulation material in an I.ITGR, SO, although Hastelloy X is least affected by the Type 304 (18-8) stainless steel is made susceptible to environment. intergranular corrosion when heated in the temperature range of approximately 1200 to 1400~~.This heat 15 treatment imparts resistance to intergranular corrosion CORROSION OF STAINLESS STEELS BY ZINC for Type 430 (18% Cr) steels. Quenching from 1400'~ VAPOR, G. A. Bennett, P. A. Nelson, and L. Burris, Jr. to 2000~~provides optimum resistance to Type 304 (Argonne National Lab., Ill.) Trans. Met. Soc. AIME, and makes Type 430 susceptible to intergranular 233, 1032-6 (1 965). corrosion. The major compositional difference in these RFP- 1 733
steels is nickel (8% and 0%). Alloys containing inter- The oxide films formed under some different conditions mediate nickel compositions were cast, rolled, heat on an AISI 304 stainless steel have been investigated by treated, and tested to determine the influence of this electron micorscopy and electron diffraction. An influ- element on corrosion behavior. It was found that the ence of the electropolishing of the metal surface was transition occurs at about 2.5 to 3% nickel. Steels with noticed as well on the nature as on the morphology of higher nickel content should be heat treated like the the oxide films. The anomalous behavior of the oxidation austenitic steels and those below like the ferritic steels. at the grain boundary area in precipitation-treated steel An unexpected result was the good resistance to inter- foils was hardly detectable in as-treated foils. The granular corrosion of all of these alloys when water reduced oxidation in these areas was only clearly ob- quenched from 1400'~to 2000'~. served in foils electropolished prior to oxidation. How- evel, IIU dlfferal~ceIn cun~posiliuncould be dele~led 19 bctwcen the grain boundary area and the inside of the STUDIES OF STEEL CORROSION IN HIGH TEM- grain. PERATURE WATER AND STEAM, Quarterly Report No. 18, January 1-February 28, 1967 (Societe d'Etudes, 22 de Recherches et d'Applications pour l'Industrie, SELECTIVE REMOVAL OF CHROMIUM FROM TYPE Brussels, Belgium) (EURAEC-1850) (1 967). 304 STAINLESS STEEL BY AIR-CONTAMINATED The study of austenitic grades of stainless steel with LITHIUM, R. E. Seebold, L. S. Birks, and E. J. Brooks high recrystallization temperatures was continued to (Naval Rcocarch Lab., Washington, D. C.), Corrosion, permit exploitation, at temperatures above 500°c, of 16, 468t-70t (1960). the improvement produced by suitable surfact? 'l'he corrosive action of 'high-pWity and air-cantaminared machining in the corrosion behavior of stainless steels in lithium on Type 304 stainless steel was studied in non- superheated steam. Although these special grades of isothermal closed systems in which maximum and steel do not recrystallize at temperatures of the order minimum temperatures were 1500 and 800'~. Chromium of 600 to 700°c, their behavior is unfavorable in super- is selectively removed to depths of 10 microns from the heated steam after machining and relatively long anneal- surface of stainless steel by air-contaminated lithium ing at these temperatures. With regard to AISI 304. at 1500~~and remains dissolved in the lithium where it stainless steel, the H2 diffusion method confirmed that is soluble to the extent of at least 25%. The other steel work hardening several tens of microns deep is required constituents are mass transferred in their origilial relative to ensure good long-term behavior in superheated steam proportions and deposited as strongly magnetic dendrites. at 500'~. In the wholly recrystallized state, it was The preferential leaching of chromium is proposed as found that a special grade of austenitic 1818 steel con- the initial step in the corrosion of stainless steel by air- taining 0.2% C, 1.5% Si, and 4% W is far less corroded in contaminated lithium. superheated steam at 600 and 700'~than the standard 18/10 grades. Moreover, this grade is far less sensitive to 2 3 intergranular corrosion in this medium. UNUSUAL CRYSTAL GKOWI'HS OBSERVED 1N THE HIGH-TEMPERATURE CORROSION OF 304 STAIN- LESS STEEL AND IRON, Research Report 6-94602-1- 20 R5, Ea~lA. Gulharratrr, Tlioi~~ssP. Copnn, nnd Daniel THE RELATIONSHIP OF NITROGREN CONTENT OF van Rooyen, (Westinghouse Electric Corp. Research AUSTENITIC STAINLESS STEELS TO STRESS Labs., Pittsburgh) (NP-7699) (1 957). CORROSION, Quarterly Report No. 438-12, Thomas B. Electron microscope and e!ectron diffraction studies Cox, (Dept. of Metals and Ceramic Engineering, Virginia were made on the corrosion products formed on 304 Polytechnic Inst., Blacksburg) (EURAEC-1902) (1 967). stainless steel and iron in dry air and oxygen, oxygen The results from stress corrosion tests performed in saturated at 25'~with water vapor, and oxygen satu- Type 304 stainless steel plates are presented. The plates rated at 25'~with H20vapor plus a few parts per were subjected to various N2 bearing atmospheres for million of HCl vapor. In addition to the formation of 24 hr at 538'~. '1.0 make certain that the specimens the normal layer type of oxide film, many fine oxide were homogeneous in nitrogen content, they were whiskers were formed on iron at 500'~in wet and dry encapsuled individually under a vacuum in quartz tubing oxygen atmospheres. These whiskers grow nearly per- and held at an elevated temperature for annealing. pendicular to the surface and were 300 to 1000 angstroms Annealing results for 1800'~and 2000'~are presented. thick and up to 470,000 angstroms long. The density of whiskers was l n8 to 1 o9 per cm2. The oxide was a-Fez 03. With stainless steel, oxide whiskers of Cr2 O3 2 1 were formed 100 to 500 angstroms thick and up to IMPERFECTIONS IN METALS, 11: CORROSION AND 50,000 angstroms in length. Some areas of the specimen OXIDATION, Quarterly Report No. 15, April 1-June 30, were free from whiskers while other areas contain up to 1966 (Centre d'Etude de I'Energie Nucleaire, Mol, lo8 whiskers per cm2. In atmospheres containing HCI Belgium) (EURAEC-1757). vapor at 600°c, fan shaped single crystals of Cr203 were formed. These grow nearly perpendicular to the the cause of failure or to use improved alloys that surface and were about 100 angstroms thick, 10,000 to would be less susceptible to failure. A materials screening 5,000 angstroms in height and 100,000 angstroms long. test was developed in the out-of-pile superheat facilities These crystals appear in parallel layers. Pre-straining of with 1.5 ppm chloride added as sodium chloride to the the specimens with stress levels greater than the yield recirculating water in the presence of typical boiling- point greatly accelerates the growth of the fan shaped water reactor quantities of oxygen and hydrogen. crystals. It was proposed that this crystal habit may be During the test, the heater sheaths were exposed through important in determining whether a given alloy is sus- several cycles to saturated steam (with its accompany- ceptible to stress corrosion cracking. ing moisture carryover) and superheated steam. Failure of Type-304 stainless steel was obtained in periods of less than two weeks; the failures were predominantly 24 transgranular. Type-347 and vacuum-melted Type-304 PHYSICO-CHEMICAL STUDIES OF CLAD UO IN stainless steels failed in this NaC1-cycle test while POTENTIAL MELTDOWN ENVIRONMENTS, J. F. White, (Nuc. Materials and Propulsion Operation) Inconel-600, Incoloy-800, Hastelloy-X, Type-406 stain- (GEMP-1004) pp. 316-50. less steel, and vacuum-melted Type 310 stainless steel were acceptable. An improved chloride cycle test with Air oxidation rate of 304 stainless is lo3 times less than 0.5 ppm chloride added as ferric chloride to the recir- rate in steam up to 1370'~due to excess Cr2 O3 film culating water was developed. An intergranular failure formation. During steam oxidation, the film provides was obtained similar to that experienced in the super- less protection because of its spinel structure. Tensile heat fuel cladding failures in the superheat in-pile loops strength of annealed 304L decreased from 0.66 kg/mm2 in the Vallecitos Boiling-Water Reactor. Sensitized at room temperature to 0.86 kg/mm2 at 1375'~. Type-304 and 'I'ype-316 stainless steels failed inter- Thermal conductivity increased with temperature. granularly in this test. Inconel-600, Incoloy-800, and vacuum-melted Type-3 10 stainless steel did not fail when 25 exposed to the test for much longer time periods. . HIGH TEMPERATURE OXIDATION, H. M. McCullough, During the development and performance of the cycle Ohio State Univ. Studies, Eng. Exp. Sta. News, 19, runs, the superheat facilities were exposed to a myriad 38-41 (1 947). of conditions within the extremes of the test parameters The corrosion rates at temperatures between 850' and involved. Intergranular chemical attack was experienced 2 1OOOF of Types 304 and 41 0 stainless steel were mea- essentially independent of stress, but the attack was sured by weight gain and weight loss techniques. The generally distributed. In the presence of high stress, the scales were chemically analyzed and examined micro- intergranular attack was more localized and advanced scopically. A compact protective chrome-iron spinel normal to the stress. It is hypothesized that a definite interplay exists between chemical attack and stress, and oxide formed under conditions of low oxygen concen- , tration while a porous non-protective iron oxide formed that the application of the stress increases the rate of the at higher oxygen concentration. intergranular attack preferentially in a direction perpen- dicular to the stress. 2 6 FORMATION OF OXIDES ON SOME STAINLESS STEELS AT HIGH TEMPERATURES, H. M. SECTION D McCullough, M. G. Fontana, and F. H. Beck, Trans. General Abstracts on Stainless Steel Corrosion Am. Soc. Metals, 43, 404-425 (1 951). Combination of visual observation, chemical analysis 28 and electron diffraction examination indicates that an Corrosion, Volume 1, Corrosion of Metals and Alloys, initial oxide of FeO . Cr2 O3 spinel forms on AISI edited by L. L. Shreir, John Wiley & Sons, New York, Types 304 and 430 stainless steels by high temperature 1963 oxidation. 29 27 The Corrosion and Oxidation of Metals: Scientific LOCALIZED CORROSION OF STAINLESS STEELS Rinciples and Ractical Applications, UIick R. Evans, AND HIGH-NICKEL ALLOYS IN SIMULATED SUPER- St. Martins Press, New York (1968). IIEAT REACTOR ENVIRONMENT, W. L. Pearl, Q. 0. . Gaul, and G. P. Wozadlo (General Electric Co. Vallecitos 30 Atomic Lab., San Jose, Calif.) USAEC Report SYMPOSIUM ON CORROSION FUNDAMENTALS. (GEAP-4450) (1964). A scrics of lcctures presented at the University of A program was instituted to study and reproduce the Tennessee Corrosion Conference at Knoxville on in-reactor intergranular failures of Type-304 stainless March 1, 2, 3, 1955, Anton de S. Brasunas and E. E. steel fuel cladding found In superheated steam. The Stansbury, eds., University of Tennessee Press, Knox- pruy was dbecled Luwa~dfi~~di~lg ways Lu eli~l~il~ale ville (1956). The following papers were presented at the symposium 3 3 on corrosion fundamentals at the University of THE MECHANISM OF CORROSION CRACKING OF Tennessee on March 1 to 3, 1955: corrosion and metal AUSTENITIC STEELS, A. V. Ryabchenkov and V. M. structures; nature of corrosion; atmospheric corrosion; Nikiforova, AERE-1iblTrans-747. Translated by J. Adam coatings for atmospheric corrosion protection; high from Metalloved., 8, 2-1 1 (1956). temperature corrosion; liquid metal corrosion; principles The aim of this work was to establish the role of electro- of cathodic protection; corrosion problems in steam chemical factors in the process of corrosion cracking of power and industrial boiler plants, corrosion failures highly alloyed austenitic steels and to study the influ- in chemical plants, inhibition of metallic corrosion in ence on these steels of static tensile stresses and corroding aqueous media; passivation of stainless steel; the media, i.e., electrolyte solution. It is concluded that influence of mechanical factors on corrosion; geometric the electrochemical theory is the most accurate of the factors in electrical measurements relating to corrosion existing theories, since there is a basis for supposing and its prevention; cathodic protection principles and that the electrochemical factor of corrosion plays the system design; and the use of plastics and plastic liners leading part in the process of corrosion cracking. for corrosion protection. 31 34 EXPOSURE OF REACTOR STRUCTURAL MATE- OXIUATION OF METALS, A. U. Seybolt (General RIALS TO IMPURE HELIUM AT ELEVATED TEM- Electric Researclr Lab., Sclrc~~c~LaJ~,N. Y.), Adwrt., PERATURES, A. F. Weinberg and J. M. Scoffin Phys., 12, NO. 45, 1-43 (1963). (General Atomic Div. General Dynamics Corp., The scientific background of metal oxidation is reviewed. San Diego, Calif.) USAEC Report (GA-2998) (1962). Some of the contributions leading toward an under- In the High-temperature Gas-cooled Reactor (HTGR), standing of the mechanisms of oxidation are also structural metals will be required to operate at tempera- reviewed. Suggestions arc made relating to needed tures of 1000 to 1400'~in an impure-helium environ- research in this field. ment for extended periods of time. Six candidate materials for such applications, including nickel alloys 3 5 and stainless steels, were subjected to simulated reactor CHEMICAL ANALYSIS OF STAINLESS STEEL environments for times up to 3000 hr to evaluate the CORROSION PRODUCTS, J. R. Ciarancllo and K. E. extent of corrosion and the changes in mechanical combs (Knolls Atomic Power Lab., Schenectady, N. Y.) properties occasioned by such exposures. Under the (TID-16092) (1959). experimental exposure conditions (helium containing A synopsis of colorimetric procedures used for the 200 to 300 ppm CO and 200 to 400 ppm Hz, or helium determination and analysis of the corrosion products containing 2000 to 3000 ppm CO and 2000 to 3000 ppm obtained from stainless steel is presented. The chief Hz, at temperatures of 1200 or 1400~~)oxidation corrosion product is Fe304,which represents -50% rather than carburization appears to be the main of the sample. Other major elements are nickel, corrosion process; however, in some cases alternating chromium, manganese, cobalt. zirconium, copper, and carburization and decarburization were observed. Mea- zinc. surements of weight gains are described. None of the materials studied exhibited a large change in their mechanical properties after exposures at 1200'~. After 36 exposures at 1 ~OO'F,moderate changes in mechanical A STUDY OF WET STEAM AS A REACTOR properties were observed for all materials except Type COOLANT, Progress Report for the Month of September 321 H stainless steel, which exhibited a large decrease in 1960 (Nuclear Development Corp. of America, White ductility after 1500-hr exposure to the higher impurity Plains, N.Y.) (TID-6893) (1960). concentration. In general, the control specimens were Progress is reported on a research and development affected as greatly as the specimens exposed to the program to study water-steam mixtures and their use impure helium environments, under the conditions of as coolants in light-water-moderated power reactors. these tests. All heal-[ransfel and burn-out tests on round tubes were 32 completed. Corrosion and erosion tests indicated that no ATMOSPHERIC CORROSION OF METALS UNDER detectable damage to Zircaloy and stainless-steel samples RADIATION, A. V. Byalobzheskii (Inst. of Physical results after exposure to fog-glow for 120 to 150 hr Chemistry, Academy of Sciences, USSR). Doklady Akad. with velocities of 200 ft/sec at a coolant temperature Nauk S.S.S.R.,119, 515-17 (1958) (In Russian). of 5 1O'F and a pressure of 750 psi. Investigations were made of radiation effects on the corrosion processes in iron, copper, aluminum, stainless 3 7 steel, and zinc in the atmosphere with 98% humidity. UNUSUAL OXlDATlON STATES ENCOUNTERED IN The results showed that in many instances the ionizing CORROSION PROCESSES, E. C. Pitzer (Knolls Atomic radiation intensified corrosion processes in the metals. Power Lab., Schenectady, N.Y.) (TID-6408) (1960). A tabulation of oxidation states of common metals is 4 1 presented. The effects of corrosion environment on the CORROSION OF HIGH STRENGTH STEELS IN oxidation state are discussed. CARBON DIOXIDE FOR GAS COOLED POWER REACTORS, Goro Ito, Seiichi Ikeda, and F. Sawayanagi (Corrosion Res. Div., Natl., Res. Inst. Metal., Tokyo), 38: Roc. Mem. Lect. Meet. Anniv. Found. Nat. Res. Znst. THE MECHANISM OF OXIDATION AT HIGH TEM- Metals. 1 Oth, Tokyo (1966) pp. 184-5. PERATURES OF AUSTENITE STEEL WITH 18% Cr-8% The high temperature oxidation of stainless steels by Ni, Jacques Benard, Jean Hertz, Yves Jeannin, and Jean C02 was investigated. Included is an evaluation of the Moreau, Compt. Rend.,'248, 2095-7 (1959) (In French). effects of welding method, temperature, flow rate, and The oxidation of Cr-Ni steel was investigated at 1050'~ moisture content on the C02-steel reaction. All of the by a kinetic study and microscopic, x-ray, and electron runs were made with 2 X 20 X 20 mm coupons which diffraction examination. The results show that the had been mechanically cleaned with emery paper. The oxidation has an initial period of slow oxidation. This reaction was found to obey a parabolic rate law indi- period of oxidation follows a parabolic law. The oxide cating a diffusion controlled reaction. At 400'~the film formed appears to protect the alloy for a time. oxide penetration was equivalent to 0.01-0.04 mm Then the second period of oxidation occurs which is per 20 years. At 500'~this was increased by a factor characterized by a rapid oxidation. This period continues of 10 and at 600'~by another factor of 10 to about until the elimination of iron from the chromium-poor 20 mm per 20 years. The addition of 0.05% water to a layer is achieved. Then the third period, characterized flowing stream of C02 showed no effect. by a slow oxidation, appears. 42 CORROSION BEHAVIOR OF STEELS IN C02/CO 39 ATMOSPHERES, C. S. Campbell, D. Goodison, W. CORROSION OF METALS BY HYDROGEN SULFIDE Jepson, and C. G. Stevens, (AICONF 28/p/157). AT HIGH TEMPERATURES, Kh. L. Tseitlin, L. V. The reactions of mild, low alloy and stainless steels in Merzloukhova, and V. A. Strunkin (Inst. of Organic COz /CO atmospheres have been studied in support of Semi-Products and Dyes), Zhur. Riklad. Khim., 30, the development of power reactors cooled by carbon 1553-8 (1957) (In Russian). dioxide. Protective oxide films have been formed on Dry hydrogen sulfide induced considerable corrosion in low alloy steels in carbon dioxide based environments at temperatures up to 55o0c, although under some carbon steel at 250'~temperature with a sharp increase at 500'~. The corrosion of stainless steel began at circumstances the films lost their protective character and the oxidation rate increased markedly. Film break- 360~~and Al-Fe and Al-Cr-Fe alloys at 500'~. In some down could be localized for a considerable time, e.g., cases water vapor slowed down the corrosive effects , 20,000 hr, and then be either general or.localized. It of hydrogen sulfide at high temperatures. A strong was associated with temperatures >350°C, high pressures, dilution of hydrogen sulfide with nitrogen weakens its i.e., 14.6 psi, in the presence of water vapor, and to a corrosivc cffccts on stainless steel. This does not hold at lesser extent in carbon dioxide. The behavior of a given a temperature of 500'~. At high temperature, steels steel was often inconsistent with respect to breakdown; and steel alloys corrode faster in dry chloride than in no correlation could be found with steel composition dry hydrogen sulfide, while in the presence of water although rimming steels were most susceptible to vapors the picture is reversed. localized breakdown. A basic study of the oxidation and carburization of a 20 Cr/25 Ni/Nb stainless steel [fuel element canning material for the Advanced Gas 4 0 Cooled Reactor at Windscale (WAGR)] has been carried FISSION PRODUCT DIFFUSION INVESTIGATION out in pure C02. CO, and mixtures of these gases at FOR CLOSED CYCLE GAS COOLED REACTOR 600-850'~. Thin protective oxide films were formed PROGRAM (Ford Instrument Co., Long Island Cify. in all instances. Carbon transferred from the gas phase N. Y.) USAEC Report (FICO-110) (1958). during film growth readily passed through the oxide A continuation of pellet irradiation work is described. into the steel while carbon deposited on the surface The scope of work was expanded to inclilde in-pile of a preformed oxide film diffused only slowly during irradiation of the enriched U02 pellets in a COz atmo- a subsequent anneal in an inert atmosphere. The pene- sphere in addition to the helium atmosphere arrange- tration of the carbon into the steel was determined and ment previously described. Gas samples from each at temperatures 2750'~a maximum up to 75pm from pellet experime.nt were analyzed to'determine the nature the oxide/metal interface was found in the carbon con- of any fission-product activity. The apparent imcom- centration-penetration curve. The oxidation of WAGR patibility of C02 and stainless steel at elevated tem- fuel element cans has been studied under simulated peratures is discussed and photographs of test results reactor operation and fault conditions involving a tem- are included. perature excursion and ingress of steam and air into the coolant circuit. The behavior was satisfactory for pro- 46 tracted periods in C02 up to 750°c, but at higher CORROSION EVALUATION TESTS OF: I. temperatures loss of fin profile occurred which could AUSTENITIC STAINLESS STEEL; 11. WELDED adversely affect the heat transfer properties of the cans. AUSTENITIC STAINLESS STEEL, A. P. Krijff and The behavior was not significantly affected by total A. Deviser, IGRL-TIC-109. Translated by R. G. Evan pressure of additions of CO, H20, or air to the gas. (U.K.A.E.A., Risley), Smit Mededel., 9, 38-49, 79-87 (1 954). The laboratory methods of corrosion testing of austenitic 43 stainless steels are reviewed, and the advantages of the CORROSION BEHAVIOR OF STRUCTURAL boiling nitric and metallurgical tests are outlined. The METALS IN IONIZED AIR, I. V. Shatalov and V. A. results of laboratory tests on different types of stainless Nikitina (U.S.S.R.) (AICONF 151Pl2042). steel-plate material are discussed. A survey on the The results of investigations on the corrosion behavior method of corrosion testing of welded austenitic of copper, aluminum, carbon steel, and stainless steel stainless steel is presented. The influence of plate- in air ionized by alpha particles are reported. The material properties on the test results is outlined, as well influence of relative humidity and radiation intensity as the influence of plate thickness. was studied. 47 CORROSION OF STAINLESS STEEL AND HIGH NICKEL CONTENT ALLOYS IN HIGH- 44 TEMPERATURE SUPERHEATED STEAM, SPECIAL BIBLIOGRAPHIC SURVEY OF CORROSION, 1954- REPORT No. 8, M. Warzee, C. Sonnen, J. Cremer and 1955. A compilation of Corrosion Abstracts, A. Irene Ph. Berge, (Societe d'Etudes, de Recherches et Humphrey, (National Association of Corrosion Engineers, d'Applications pour l'Industrie, Brussels, Belgium) (Houston. Texas) (Publ. No. 58-1) (1958). (EURAEC-1895) (1967). The abstracts have been arranged in accordance with A series of Fe-Ni-Cr alloys has been subjected to static the NACE Corrosion Abstract Filing Index. Cross corrosion tests in steam, at 500 to 700~~and 70 kg/cm2. references have been included to take care of those When the surface structure of these alloys is normally abstracts which might be placed under another heading crystallized, corrosion is generally inversely related to than the one chosen. Author and subject indexes have the Ni content of the alloy. It was found that a special been added to facilitate searching for specific grade of austenitic steel, containing 0.2% C, 1.5% Si, and information. 4% W, is much less affected by corrosion in steam at 600 or 700'~than the conventional 18110 grades. The behavior of these alloys in superheated steam, depends 45 more on the absence of local corrosion at grain bound- CORROSION OF METALS IN TROPICAL ENVIi aries and nn the hnmngeneity nf the alloy suhjacent tn RONMENTS, C. R. Southwell, B. W. Forgeson, and the oxide layer. Heterogeneities at the grain boundaries, A. L. Alexander (U. S. Naval Research Lab., Washington), that seem of little importance when the corrosion process Corrosion, 14, 435t-9t (1958). goes on in the absence of mechanical stresses, develop Results are reported of 8-year exposure tests made to into a deep intergranular attack when the corrosion determine the corrosion characteristics of ten structural process occurs together with stresses such as those due steels exposed to seashore and inland environments in to the steam pressure exerted inside tubular samples. the Panama Canal Zone. These corrosion rates are Microscopic examination of various oxidized steel grades compared with existing data for the same materials in suggests that a high carbon content and the absence of temperate zones. Data reported include a summary stabilizing elements in the alloy might be favorable. of individual analyses of air samples obtained at atmo- When these alloys are surface cold-worked prior to being spheric test sites, and extensive weight-loss and pitting subjected to superheated steam, intergranular attack data for the ten steels, at 1. 2.4. and 8-year exposure phenomena are avoided, and influence of the composi- intervals. Numerous time-corrosion curves in tropical tion of the alloy on the corrosion level is no longer marine and tropical inland exposures are given for the noted, the corrosion level being very low. External steels. Considerable attention is given to the effect of selective oxidation of Cr and possibly of Mn ensures low-alloy additions on mild carbon steel. It was found the protection of all these alloys. By extending the that the corrosion of copper steel in the two tropical test duration to about one year, it has been established atmospheres was only 13 and 14% less than that of the that a cold-worked depth of several tens of microns unalloyed mild steel. The 2 and 5% nickel steels were must be attained by the machining process chosen, very effective in resisting corrosion as was nickel steel. otherwise the oxidation behavior of the cold-worked The four proprietary low-alloy steels tested displayed alloys lessens after a varying period of time. Absence of good corrosion resistance to tropical atmospheric recrystallization of the cold-worked areas imposes a corrosion. limiting value to the temperature for each kind of alloy. The presence of oxygen in the steam (20 ppm) does The oxide layers formed at temperatures between 450 not modify the behavior of the cold-worked alloys. and 620'~and pressures between 1 and 25 kg/cm2 Thermal treatments under and extremely low oxidizing were studied by micrography and x-ray scattering on atmosphere, e.g., PH O/PH = lo-', may have a pro- iron and steel samples. In addition to the classic 2 tective action for ~ehi~rrecrystallized alloys. External corrosion, a carburization phenomenon was observed selective oxidation of chromium diffusing through the at high pressures. Amorphous carbon was identified in grain boundaries explains this protection which, to be or on the oxide in all the tests. Orientation of the complete, requires a maximum grain size of several magnetite was also observed. The corrosion by carbon microns. dioxide is very different from the corrosion by air or oxygen, because of the secondary reactions. 4 8 COMPATIBILITY OF STAINLESS STEELS WITH 52 CARBON DIOXIDE AT ELEVATED TEMPERA- ELEMENTS OF THE COMPOSITION OF MATERIALS TURES, H. Loriers, D. Leclercq, and R. Darras (CEN, CONTAINING NICKEL WHICH PREVENT DRY Saclay, France), Mem. Sci. Rev. Met., 60, 177-88 CORROSION AT HIGH TEMPERATURES, R. A. (1 963) (In French). Smith, Corrosion Anti-Corrosion, 12, 108-15 (1964) Among the common types of stainless steel, those (In French). stabilized with niobium show the greatest resistance to The results of studies on the effects of the compo- oxidation by carbon dioxide under pressure between sition of different materials containing Ni and of the 600 and 700'~;they could represent a convenient temperature on the resistance of these alloys to corro- canning material for fuel elements in advanced nuclear sion are reported. The resistance to oxidation to 1200'~ reactors. in air, Hz S, C02,CO, and SO2 is analyzed to obtain data on the possibility of modifying the behavior of 49 STUDIES ON THE COMPATIBILITY OF HIGH- the metal in the environments. TEMPERATURE CARBON DIOXIDE WITH STAIN- '. , .. LESS STEELS AND OTHER MATERIALS (General 53 Nuclear Engineering Corp., Dunedin, Fla.) (GNEC-121). ON OXIDATION MECHANISM OF METALS AND ALLOYS, J. Markali (Central Inst. for Industrial Research, ' , - ' The compatibility of C02 with various stainless steels, Blindern, Oslo), Research (London), 10, 367-9 (1957). aluminum-chromium-iron alloys, chromium steel, carbon The rate of oxidation of metals as influenced by oxide steel, and nickel alloys was studied at 1050 to 1300~~. thickness variations and surface area is discussed. The effects of temperature, pressure, gas velocity, solution annealing, and water vapor in C02 on the 54 corrosion rates of the above alloys and stainless steels BIBLIOGRAPHIES OF CORROSION PRODUCTS, were studied. A. H. Roebuck (Continental Oil Co., Ponca City, Okla.), . .I..: ,,. Corrosion, 13, iiit-2it (1 957). : .-:. .. 50 Selected abstracts arranged chronologically, with most STUDIES ON THE COMPATIBILITY OF HIGH- recent abstracts first, are included on the identification , TEMPERATURE CARBON DIOXIDE WITH STAIN-. and composition of corrosion products on stainless LESS STEELS AND OTHER MATERIALS, W. A. steels, zinc, zirconium, titanium, and iron and steel. Maxwell (Gelreral Nudear Enghleetir~~Corp., Dunedill, Included are 43 abstracts on stainless steels, 13 on zinc, Fla.) (TID-7597) pp. 674-97. 7 on zirconium, 8 on titanium, and 130 on iron and Materials are being tested for compatibility with C02 steel. The last category includes an alphabetical author for use in the Florida Power Reactor. Stainless steels, list. Fe-AICr alloys, Ni alloys, Croloys, and carbon steels are among the materials studied. The effects of tem- 55 perature, pressure, solution annealing, gas velocity, and POWER REACTOR TECHNOLOGY, Technical Progress presence,of water vapor on corrosion rates were Reviews, Vol. 3, No. 1, Walter H. Zinn, ed., (General determined. Nuclear Engineering Corp., Dunedin, Fla.) (1 959). General Research and Development. Section one: 5 1 reactor applications. . .Section two: thermionic energy PROPERTIES OF SURFACE FILMS FORMED conversion. . . In the third section the reactor physics DURING THE DRY CORROSION OF IRON AND of Hz 0-moderated critical assemblies is discussed. The STEEL BY CARBON DIOXIDE UNDER PRESSURE, fourth section discussed heat transfer and fluid flow. P. Bastien and M. Colombie (I'Ecole Centrale, Paris), Section five is devoted to reactor kinetics and dynamics. Corrosion Anti-Corrosion, 11, 169-75 (1963) In the sixth section reactor safety and containment are (In French). discussed. A re.view of shielding is present in the seventh section. In section eight the radiation effects on 60 semiconductors and magnetic materials along with the HIGH TEMPERATURE CORROSION OF METALS, corrosion of stainless steel in a nitrogen atmosphere A. Dravnieks and H. J. McDonald, Znd. Gas, 27, 6-12 are reported. (1949). Progress on Specific Reactor Types. The four sections Thermodynamics and other descriptions of conditions comprising this part of the volume are devoted to light- characteristic of attack.on stainless steels. water reactors, boiling-water reactors, fluid-fuel reactors, and fluidized-bed reactors. 61 THE CORROSION OF ALLOY STEELS BY HIGH- 5 6 TEMYEKATUKE STEAM, 6. A. Hawkins, J. 1'. Agnes, COMPATIBILITY OF CLADDING MATERIALS WITH and H. L. Solberg, Trans. Am. Soc. Mech. Engrs., 66, CARBON DIOXIDE AT HIGH TEMPERATURES, 291-295 (1944). Raymond Darras and Henri Dumond (France, Unstressed specimens of low carbon, chromium and Commissariat a 1'Energie Atomique) (A/CONF.28/P63) chromium-nickel steels were exposed to steam at tem- (1964). peratures between 100' and 1800~~.The scale removed The results of tests on the resistance of Be, Be alloys, from the corroded specimens was analyzed chemically.. stainless steels, A1-Fe alloys, Zr, and Zr alloys to cor- rosion and/or oxidation in C02 at temperatures of 6 2 500 to 700'~and high pressures are presented. The STUDIES ON HIGH TEMPERATURE OXIDATION effects of impurities in the gas were carefully examined OF STAINLESS STEELS, I. Iitaki, T. Nakayama, and in the case of Be and Be alloys. It is concluded that K. Srhigirdii, J. ,3ci. Rs~ctrr~.ltItl~t. (Ttikyt,), 4.5, SF64 stainless steels are still the most suitable cladding mate- (1951). rials for temperatures of 500 to 700~~and high pressures. Electron diffraction studies of the oxide layers produced nn Fe-Cr-Ni and Fef r alloys at 900'~indicate that the presence of Ni reduces corrosion; Ni-NiO layers in the 57 oxide film retard diffusion of metal atoms from the A STUDY OF THE REACTIONS BETWEEN INDI- substrate. Molybdenum reduces the resistance of steel VIDUAL OXIDES FORMED DURING THE to oxidation; low boiling Moo3 crystals in the film OXIDATION OF STAINLESS STEELS, W. H.Whit1ow decrease the adherence of the film at high temperatures. and J. H. Buddery (Berkeley Nuclear Labs., Central Electricity Generating Board, Berkeley, England) 63 (RD/B/N-1272) (1969). OXIDATION MECHANISMS OF BINARY IRON- CHROMIUM ALLOYS AT ELEVATED TEMPERA- Stability tests were made on the individual oxides of TURES, J. Moreau, Compt. Rend., 236, 85-87 (1953). Fe, Ni, Cr, Mn, and Si at 1000~~and in a vacuum of lo-' tom. Reactions between these oxides under similar Through x-ray and metallographic examination the si.ele\ f'c~irlletl Iry tl~ctl~ill~I11)ll of L~II~III~UIIIsleel~ at conditions were also studied. X-ray powder diffraction techniques were used to follow the course of the oxide/ 800' 1" 1250'~WLI~ alialyEcd. Tllc laycr adjaecnt to oxide reactions. Three types of reaction are prominent: the metal was comprised of Cr embedded in FeO; the layer above this was a mixed spinel oxide containing A0 + BO + (A,B) 0;A0 + B2 O3 + AB204; and reactions with Si02. Fe and Cr while the exterior layer consisted of a-Fe203. 64 OXIDE FILM COMPOSITION STUDIES, T. N. Khodin, 58 Ann. N. Y. Acad.Sci.,SR,(1954). PROTECTIVE FILM FORMATION ON STAINLESS Structural and compositional properties of oxide films STEELS, W. H. Colner. Corrosion and Materials Protect., on alloys of stainless steels and related alloys are corre- 4, 11-21 (1947). lated with resistance to air corrosion and high tempera- Composition and properties of protective oxide'films ture oxidation. on 18-8 stainless steel are described. 6 5 OXIDE FILM ON STAINLESS STEELS, N. Tuk!!mItr, Nature, 145, 589-90 (1949). Sci. Papers Inst. Phys. 59 Chem. Research (Tokyo), 38, 59-62 (1950). THE PRODUCTS OF CORROSION IRON OXIDES, - Electron diffraction methods were used to study sur- HYDRATED OXIDES AND HYDROXIDES, R. C. Corey. face oxides on the entire system of NiCr. The oxide Combustion, 18, 45-51 (1946). which is formed between -60YC is a-(Fe,Cr),03. The A brief resume of the chemical and physical properties of oxide which is formed at 1000 C is similar to the the iron oxides and hydroxides is given. Fe304 type. 66 Low Carbon steel boiler plate begins to react with steam THE NATURE OF PASSIVITY IN STAINLESS STEELS at 410'~;stainless steel begins to react at 780'~. Iron AND OTHER ALLOYS, H. H. Uhlig and J. Wulff, Am. reacts with wet oxygenated steam to form Fe(OH)3 and Inst. Mining & Metal. Engrs., Iron and Steel Div. Metals with dry oxygenated steam to form a protective coating Technol., 6., T. P. 1050 (1939); T. P. 1051 (1939). of oxides. In presenting their theory of passivity the authors 70 claim that a stiidy of the corrosion products of stainless ELECTRON DIFFRACTION STUDIES ON THE steel indicates'that the surfaces of the alloy have the same composition as the bulk alloy. NATURE OF THE CORROSION RESISTANCE OF STAINLESS STEEL, S. Yamaguchi, T. Nakayama, and 67 T. Katsurai,, J. Electrochem. Soc., 95, 1, 21-4 (1949). AMOUNT OF OXYGEN ON SURFACE OF PASSIVE Electron diffraction studies were made of 18-Cr, 4-Ni STAINLESS STEEL, H. H. Uhlig and S. S. Lord, Jr., and 19-Cr, 9-Ni stainless steels exposed to water vapor J. Electrochem. Soc., 100, 216-21 (1953). at elevated temperatures and pressures. The data indi- cate that the resulting oxide may be a solid solution of The nature of the passive surface of 18-8 stainless steel is discussed in terms of oxygen adsorption. (Ni, Fe) Cr04.
68 7 1 ELECTRON DIFFRACTION STUDY ON THE I A STUDY OF THE SURFACE FILM ON CHROMIUM- CORROSION OF METALS, S. Yamaguchi, Japan Sci. NICKEL (1818) STAINLESS STEEL, W. H. J. Vernon, Rev. Ser. 1, 1, 2431 (1949) (In English). F. Wormwell, and T. J. Nurse, J. Iron Steel Inst., 1.50, 81-92 (1944). Oxide film on 18-8 stainless steel formed in wet air at An iodine-methanol solution was employed to strip 100'~is reported to be solid solution of Fe and Ni in CrCIJ. oxide films froiii 1010 stccl. Tl~cshipped Pllri~swere subjected to chcmical analysis. The col~~posilioncil Lhe 7 2 film was dependent on the degree and method of INVESTIGATIONS OF THE OXIDATION OF polishing and on the temperature of oxidation. The CHROMIUM AND NICKEL-CHROMIUM STEELS, film was enriched with chromium but not with J. J. Yearian (Summary of Technical Report to Office nickel. of Naval Research, Oct. 195l), Phys. Review, 82, 341 (1951). 69 EXPERIMENTAL 1NV.ESTIGATIONSON THE Discusses the structure of protective oxide scales and REACTION BETWEEN STEAM AND IRON, K. Wickert oxide films formed on chromium and nickel chromium and H. Pilz, Werkstoffe ti Korrosion, 1, 56-64 (1950). stecls during oxidation at high temperatures. LEFT BLANK AUTHOR INDEX AND ABSTRACT NUMBERS
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