Alloy 600 uns n06600 description alloy 600 is a nickelchromiumiron, solid solution strengthened alloy used for applications that require corrosion and elevated temperature resistance. Proceedings of the 10th international conference on nuclear engineering. Stress corrosion cracking of alloy 600 in an aqueous solution. In this coupling system, the electrochemical potential of alloy 600 can be shifted into the range potentially susceptible to stress corrosion cracking. Stress corrosion cracking and nondestructive examination of. Stress corrosion cracking of nickel based alloys in water. Pdf study of stress corrosion cracking of alloy 600 in high. The importance of a conjoint action of corrosion and stress as well as the nature of stress is reflected in the definition. Primary water stress corrosion cracking behavior of an. Abstract the stress corrosion cracking scc behavior of alloy 600 was studied in aqueous solutions containing lead. Thermal properties at low and high temperatures are listed in. The high nickel content of the alloy enables it to retain considerable resistance under reducing conditions and makes it resistant to corrosion by a number of organic and inorganic compounds. Figure 1 shows an analytical electron microscope aem analysis. Inconel 600 is combination of nickel chromium and iron provides a standard material for the chemical industry and the automotive engine, aeroengine and airframe sectors.
Chromium confers resistance to sulfur compounds and provides resistance to oxidizing conditions at high temperatures or in corrosive solutions. Significant diminution of the crack initiation time was observed for sample oxidised before stress corrosion tests. Grain boundary engineering gbe has been demonstrated as a viable method for improving the resistance to corrosion, and stress corrosion cracking scc,, in austenitic stainless steels ss and ni based alloys alloy 600, alloy 690. Effect of surface preparation on intergranular stress.
Stress corrosion cracking issues in syngas plants that may be. Intergranular stress corrosion cracking scc of inconel 600 is of concern to the nuclear power industry. Among the models put forward to explain alloy 600 cracking, two model families are favored today. Furthermore, the chromium material in alloy 600 provides resistance to sulfur substances. Alloy 600 is a nickelchromiumiron, solid solution strengthened alloy used for applications that require corrosion and elevated temperature resistance. Part ii stress corrosion cracking in nickelbased alloys 5. Stress corrosion cracking behavior of nickel base alloys. An experimental program on stress corrosion cracking scc aimed at the development of a quantitative model for predicting the behavior of inconel 600 tubing in high temperature water is currently underway at brookhaven national laboratory bnl. Stress corrosion cracking of nickel based alloys in watercooled nuclear reactors. This treatment can reduce the rate of intergranular stress corrosion cracking and fatigue cracking in structural metals or alloy 600 needed for nuclear power plants. Dec 31, 2019 this report includes a summary of foreign and domestic alloy 600 cracking experience, an analysis of the alloy 600 cracking susceptibility model for vessel head penetration vhp nozzles, and information on corrosion of pressure boundary materials in boric acid solutions. Laser peening is an emerging modern process that impresses a compressive stress into the surface of metals or alloys.
Experimental techniques used to investigate stress corrosion cracking scc are described, from the use of constant deformation and constant load specimens. Alloys 600 and 182 are used as structural materials in pressurized water reactors pwrs and have been found to undergo stress corrosion cracking scc. Gbe involves increasing the frequency of coincident site lattice csl grain boundaries whilst disrupting the random grain boundary. Specimens of alloys 600 and 690 were exposed to avt water at 288degree, 332degree, 343degree, and 360degreec. Jun 28, 2019 furthermore, the electrochemical behavior of magnetite and alloy 600 demonstrated that alloy 600 behaved as an anode in the coupling system with magnetite. The flexibility of alloy for use in oxidizing, carburizing, chlorinated solvents and simulated waste incinerator conditions comprise of halide species are shown. Pdf on aug 1, 2010, f leonard and others published study of stress corrosion cracking of alloy 600 in high temperature high pressure water find, read and. This study aims to investigate and explain the magnetiteaccelerated stress corrosion cracking phenomenon of alloy 600 under caustic conditions, based on the electrochemical behavior. Stress corrosion cracking models and mechanisms for inconel 600.
Pdf stress corrosion cracking of alloy 600 in high. It is one of the biggest groups in the family of nickel alloys that include alloy 600, alloy 825, alloy 800 and hastelloy g30. Stress corrosion cracking of alloy 600 in a hightemperature. This post shows the lab and field data about the resistance of inconel 625 to the diverse aqueous media causing localized attack, stress corrosion cracking and other kinds of corrosion. Heat exchangers in commercial nuclear systems have shown scc in only a fraction of a percent of the tubes in high temperature water, but laboratory scc of nicontaining alloys have been demonstrated by several research groups. Water stress corrosion cracking pwscc of alloy 600 results from a hydrogen mechanism. Stress corrosion cracking of inconel alloy 600 in high.
Pdf primary water stress corrosion cracking in alloy 600. Effect of hydrogen on the intergranular stress corrosion. With high nickel content, inconel alloy 600 is virtually immune to chlorideinduced stress corrosion cracking. Corrosion behavior of inconel 625 heanjia super metals. Alloy 600 is one alloy used in solutions of magnesium chloride. Similarly, the chromium content of alloy 600 is an improvement over alloy 200 commercially pure nickel. Comparison of the energyamplitude decibels db characteristics in the acoustic emission bursts recorded with alloy 690 no stress corrosion cracking scc and alloy 600 scc during a 258h tensile test in a primary environment stress intensity factor 30 mpa m. Abstract the fracture toughness and tensile properties of alloy 600, alloy 690 and their welds, en82h and en52, were characterized in540 and 338.
Controlled chemical composition limits are applied in the nuclear industry to eliminate the risk of stress corrosion cracking by high purity water containing chloride ions. To avoid stress corrosion cracking, the 600 alloy fabrication should be fully stress relieved prior to use. Stress corrosion cracking scc is the growth of crack formation in a corrosive environment. Pdf the mechanism of stress corrosion cracking of alloy 600. Stress corrosion cracking national physical laboratory. The chromium in the alloy offers high temperature resistance to sulfur compounds as well as resistance to oxidizing compounds at elevated temperatures or in corrosive media. Alloy 600 is employed in the fabrication of steam generator tubes in the nuclear power plants.
Predicting susceptibility of alloy 600 to intergranular stress corrosion cracking using a modified electrochemical potentiokinetic reactivation test m. Inconel 600 is a nickelchromium alloy designed for use from cryogenic to elevated temperatures in the range of 2000 deg f1093 deg c. The oxidationhydrogen alternative is still a highly controversial issue. Intergranular stress corrosion cracking of alloy 600 and x. Good corrosion resistance of the dry chlorine and chlorine hydride. Alloy 600 is not precipitative hardenable, it is hardened and strengthened only by cold work. Nuclear grade production tubing of alloy 600 was evaluated for stress corrosion cracking scc susceptibility in high purity water at 365, 345, 325, and 290 c. Ricker, national institute of standards and technology stress corrosion cracking scc is a term used to describe service failures in engineering materials that occur by slow, environmentally induced crack propagation. Stress corrosion cracking of alloy 600 tubes in high. They describe the introduction, experiment, results and discussion well organized. It is a broadly studied material for its immunity in stress corrosion cracking in warm water and caustic media. Primary water stress corrosion cracking pwscc mechanism.
Nickel alloy castings 600 is a nickelchromium alloy with good oxidation resistance at high temperatures and resistance to chlorideion stress corrosion cracking, corrosion by highpurity water, and caustic corrosion. The ordering reaction in alloy 600 causes an anisotropic lattice contraction. Stress corrosion crack initiation of alloy 600 and alloy 690. Part i historical perspectives on stress corrosion cracking of nickelbased alloys 1.
Intergranular stress corrosion cracking igscc has been studied in two similar nickelbase alloys, alloys 600 and x750, in deaerated steam at elevated temperatures 380 c. Stress corrosion cracking scc may be defined as the delayed failure of alloys by cracking when exposed to certain environments in the presence of a static tensile stress. Stress corrosion cracking of alloy 600 and alloy 690 in. However, when sulfur compounds are present as well, or for ammonium hydroxide service, 600 alloy is suggested. The mechanism of stress corrosion cracking of alloy 600 in. Scott and le calvar proposed for the first time that pwscc in alloy 600 was associated with internal oxidation phenomena selectively occurring at grain boundaries. Service temperatures for alloy 600 can be from cryogenic to 2000f. Effects of cold working path on strain concentration. The effect of a serrated grain boundary on stress corrosion cracking scc of alloy 600 was investigated in terms of improvement of scc resistance. Ahn 1 department of materials science and engineering, korea advanced institute of science and technology, 3731 kusongdong, yusonggu, taejon, korea, 305701.
Industries and applications the unique properties of alloy 600 make it. Also, alloy 600 has excellent resistance to alkalies and is one of. The alloy has superb corrosion resistance to caustic environments and resistance to dry chlorine up to 538c. Inconel 600 tube, alloy 600 tubing astm b163 b167 asme. For nuclear applications, the alloy is produced to exacting specifications and is designated inconel alloy 600t. The objective of this dissertation is to determine if accelerated scc initiation testing of alloy 600 and alloy 690 can be conducted without changing the. The stress corrosion crack growth rate of alloy 600 heat affected zones exposed to high purity water. The nickel content of the alloy renders the alloy extremely resistant to chlorideion stresscorrosion cracking. Characterizations and stress corrosion cracking evaluations. Alloy 600 is a nonmagnetic nickelchromiumiron high temperature alloy with an excellent combination of high strength, hot and cold workability and high corrosion resistance. The original davis besse reactor pressure vessel rpv head experienced intergranular stress corrosion cracking igscc of several alloy 600, control rod drive mechanism crdm nozzles. A study on the surface and crack tip oxidation of alloy.
The coriou effect presents the latest information on brittle failure of metals in corrosive chemical environments under the influence of tensile stresses nickel alloys are more resistant to scc as well as high temperatures and have been widely used in more challenging environments such as nuclear power plants. Good stress corrosion cracking resistance properties in both room temperature and high temperature. Alloy 600, a nickel base alloy containing 15 % chromium, is used in the primary circuit of pressurized water reactor pwr. Scc is highly chemically specific in that certain alloys are likely to undergo scc only when exposed to a small number of chemical environments. Primary water stress corrosion cracking pwscc of ni base alloys, such as alloy 600, is one of the main issues associated with longterm operation of nuclear power plants. Intergranular stress corrosion cracking igscc attacks the tubes in areas of high residual stress, and in crevice regions. Plant experience with alloy 600 cracking and boric. Some physical constants of inconel alloy 600 are given in table 2. Experimental tests for investigating stress corrosion cracking. Alloy 660 generally resists scc in highpurity water at normal sevice temperatures, but is susceptible to scc at higher temperatures. This anisotropic contraction produces an additional stress. Stress corrosion cracking of alloy 600 using the constant.
Sep 10, 20 an activation energy for the ordering reaction in alloy 600, q. It can lead to unexpected sudden failure of normally ductile metal alloys subjected to a tensile stress, especially at elevated temperature. The mechanism of stress corrosion cracking of alloy 600 in high temperature water. Both laboratory experiments and operation experiences in the past decades indicated that scc in alloy 600 had challenged the aging and lifetime management of lwrs. Stress corrosion cracking scc of nickelbased alloys. Alloy 600 is subject to stress corrosion cracking in hot, concentrated caustic alkalies. Pdf stress corrosion cracking scc of nickelbased alloys. Stress corrosion cracking of alloy 600 in high temperature high pressure water. Stress corrosion cracking in nickelbase alloys 690. The authors present a nice work on stress corrosion cracking behavior of alloy 600 coupled to magnetite under hightemperature 3 caustic conditions. Alloy 600 inconel 600 equivalent and supplier ams 5540. The most common type of stress corrosion cracking in stainless steels occurs in chloride environments, which will. Solutionannealed alloy 600 samples were tested under active load conditions in a superheated low pressure h 2steam environment over a range of oxidising potentials relevant to primary water stress corrosion cracking pwscc.
Stress corrosion crack initiation of alloy 600 in pwr. The mechanism of stress corrosion cracking of alloy 600 in high. Stress corrosion cracking and nondestructive examination of dissimilar metal welds and alloy 600. General corrosion and stress corrosion cracking of alloy. Reverse tube ubend specimens provided crack initiation data and constant extension rate tests were employed to determine the crack velocities experienced in th crack propagation stage. Pdf effect of serrated grain boundary on stress corrosion. Stress corrosion cracking issues in syngas plants that may be missed by riskbased assessment stress corrosion cracking has been causing problems in syngas plants since they were first developed and many of these cases have been covered in previous ammonia safety conferences. Stress corrosion cracking of inconel 600 in aqueous solutions at. Environments that may cause stress corrosion cracking in nickel alloys include hot caustic solutions, high temperature water and hot and wet hydrofluoric acid. Corious cracking in japanese pwrs and its mitigation. There have been reports on an amount of stress corrosion cracking scc in these alloy 600 components. Abstract since the start of commercial nuclear power operation, the industry has reported a variety of steam generator corrosion damage. Pdf the stress corrosion crack growth rate of alloy 600. Corrosion behavior of inconel 625 heanjia super metals co.
Pdf stress corrosion cracking scc is a major reason for failure within inconel 600 tubes in steam generators of pressurized water nuclear. Scc is often associated with chlorides, but can also occur with caustics and other corrosive media. In the hydroiodic acid at temperatures exceeding 177oc, alloy b2 was sensitive to transgranular stress corrosion cracking. Intergranular stress corrosion cracking igscc of nibased alloy 600 in the primary water of pressurized water reactor pwr has been a challenging issue faced by the nuclear power industry since the first failure reported by coriou et al.
Implication of such a finding on the crack initiation of alloy 600 is discussed. The stress level would be the maximum value about 70 and 300 mpa according to the lattice planes in alloy. The high nickel content of the material provides exceptional resistance to chloride stress corrosion. They also find something new in stress corrosion cracking of alloy 600. Alloys 690 and 152 are the replacement materials of choice for alloys 600 and 182, respectively. Primary water stress corrosion cracking in alloy 600 and intergranular crack growth rate article pdf available in metals and materials international 162. Influence of oxide films on primary water stress corrosion.
Correlation between grain boundary migration and stress. Stress corrosion cracking scc is a common issue with many specialty alloys. In both cases, igscc occurs through the nucleation, growth, and linkup of grain boundary voids rather than by grain boundary dissolution. The stress corrosion cracking scc behavior of alloy 600 was studied in aqueous solutions containing lead. A minimum treatment of 1650f for 1 hour is suggested, but 18001850f for 1 hour preferred.
The nickel content gives it excellent resistance to chlorideion stress corrosion cracking and also provides excellent resistance to alkaline solutions. This report describes stress corrosion scc tests of inconnel alloys 600 and 690 in allvolatile treated avt water. The ordering reaction in alloy 600 is an indispensable process during reactor operating conditions. Thermal properties at low and high temperatures are listed in table 3. In view of these results, a mechanism for stress corrosion crack initiation of alloy 600 in pwr primary water was proposed.
Alloy b2 is damaged by intergranular stress corrosion cracking in the heat affected region when subjected to organic solvents comprising of sulfuric acid at 120oc. Stress corrosion cracking of alloy 600 in pwr primary water. The study reported here has been designed to determine the influencing effect of sulphate ions on chloride induced crack initia tion of inconel 600 using. Operating practices introduced in the 1980s and 1990s to improve the secondary side chemistry and to reduce the. Virtually immune to chlorideon stress corrosion cracking. Stress corrosion crack scc initiation of three millannealed alloy 600 heats in simulated pressurized water reactor primary water has been investigated using. Review of the stress corrosion cracking of inconel 600. Electrochemical polarization and current transient experiments were performed at 315 c in a 40% sodium hydroxide solution to assess the effect of lead on a passive film formed on alloy 600. Effect of surface preparation on intergranular stress corrosion cracking of alloy 600 in hydrogenated steam f. Heat treatment of nicrfe alloy 600 to optimize resistance. The high nickel content of the alloy provides good resistance to reducing environments, while the chromium content provides resistance to weaker oxidizing conditions. Scenini 1 materials performance centre, po box 88, university of manchester, manchester, m60 1qd, united kingdom. Good corrosion resistance property for the reduction, oxidation, nitric and other media. This alloy also has good workability, weldability and high strength.
The stress corrosion cracking scc susceptibility of alloy 600 ma has been studied in deaerated 0. Results were compared with air data to evaluate the effect o. Stress corrosion cracking behavior of alloy 600 coupled to. Stress corrosion crack scc initiation of highly resistant materials can be studied by conducting accelerated testing as long as there is no change in the cracking mechanism. Fracture toughness, tensile and stress corrosion cracking. The nickel content contained within the wire itself allows it to be almost entirely immune to chlorideion stress corrosion fracturing. Iterative thermomechanical processing of alloy 600 for.
193 453 222 547 754 1516 1237 855 1402 1147 1596 1330 113 1233 862 1646 638 685 799 73 1640 1329 1114 1287 1642 1257 324 227 596 360 1388 1552 256 452 364 671 957 1118 993 416 211 889 1328