Abstract
The microstructural evolution during short-term thermal exposure of 9/12Cr heat-resistant steels is described, as well as mechanical properties after exposure. The tempered martensitic lath structure, as well as the precipitation of carbide and MX-type carbonitrides in the steel matrix is stable. On thermal exposure, with increase of cobalt and tungsten contents, cobalt could promote the segregation of tungsten along the martensite lath to form Laves phase, and large size and high density of Laves phase precipitates along the grain boundaries could lead to the brittle intergranular fracture of the steels. In addition, the long-term thermal ageing effect on China Low Activation Martensitic (CLAM) steel is discussed. The microstructural evolution, including the growth of M23C6 carbides and the formation of Laves phase precipitates as well as the evolved subgrains, leads to changes in the mechanical properties. The upper shelf energy of the thermally aged CLAM steel decreases with the extension of ageing time, while the yield strength changes slightly. After long-term thermal ageing, the MX-type precipitates remain stable. The growth of M23C6 and the formation of Laves phase are confirmed. The Laves phase was the main factor leading to the increase in the ductile-brittle transition temperature.
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References
Abe F (2003) Effect of quenching, tempering, and cold rolling on creep deformation behavior of a tempered martensitic 9Cr-1W steel. Metall Mater Trans A 34A:913–925. doi:10.1007/s11661-003-0222-x
Abe F (2004) Coarsening behavior of lath and its effect on creep rates in tempered martensitic 9Cr–W steels. Mater Sci Eng A 387–389:565–569. doi:10.1016/j.msea.2004.01.057
Aghajani A, Somsen Ch, Eggeler G (2009) On the effect of long-term creep on the microstructure of a 12 % chromium tempered martensite ferritic steel. Acta Mater 57:5093–5106. doi:10.1016/j.actamat.2009.07.010
Blach J, Falat L, Ševc P (2009) Fracture characteristics of thermally exposed 9Cr-1Mo steel after tensile and impact testing at room temperature. Eng Fail Anal 16:1397–1403. doi:10.1016/j.engfailanal.2008.09.003
Cui J, Kim IS, Kang CY, Miyahara K (2001) Creep stress effect on the precipitation behavior of Laves phase in Fe-10 %Cr-6 %W alloys. ISIJ Int 41:368–371. doi:10.2355/isijinternational.41.368
Fernández P, Hernández-Mayoral M, Lapeña J, Lancha AM, De Diego G (2002a) Correlation between microstructure and mechanical properties of reduced activation modified F-82H ferritic martensitic steel. Mater Sci Technol 18:1353–1362. doi:10.1179/026708302225007411
Fernández P, Lancha AM, Lapeña J, Serrano M, Hernández-Mayoral M (2002b) Metallurgical properties of reduced activation martensitic steel Eurofer’97 in the as-received condition and after thermal ageing. J Nucl Mater 307:495–499. doi:10.1016/S0022-3115(02)01013-9
Ghassemi-Armaki H, Chen RP, Maruyama K, Yoshizawa M, Igarashi M (2009) Static recovery of tempered lath martensite microstructures during long-term aging in 9–12 %Cr heat resistant steels. Mater Lett 63:2423–2425. doi:10.1016/j.matlet.2009.08.024
Ghassemi-Armaki H, Chen RP, Maruyama K, Igarashi M (2011) Creep behavior and degradation of subgrain structures pinned by nanoscale precipitates in strength-enhanced 5 to 12 pct Cr ferritic steels. Metall Mater Trans A 42A:3084–3094. doi:10.1007/s11661-011-0726-8
Hald J (2008) Microstructure and long-term creep properties of 9–12 %Cr steels. Int J Press Vessels Pip 85:30–37. doi:10.1016/j.ijpvp.2007.06.010
Hasegawa T, Abe YR, Tomita Y, Maruyama N, Sugiyama M (2001) Microstructural evolution during creep test in 9Cr–2W–V–Ta steels and 9Cr–1Mo–V–Nb steels. ISIJ Int 41:922–929. doi:10.2355/isijinternational.41.922
He Y, Yang K, Qu W, Kong F, Su G (2002) Strengthening and toughing of a 2800-MPa grade maraging steel. Mater Lett 56:763–769. doi:10.1016/S0167-577X(02)00610-9
Helis L, Toda Y, Hara T, Miyazaki H, Abe F (2009) Effect of cobalt on the microstructure of tempered martensitic 9Cr steel for ultra-supercritical power plants. Mater Sci Eng A 510–511:88–94. doi:10.1016/j.msea.2008.04.131
Hu X, Huang L, Yan W, Wang W, Sha W, Shan Y, Yang K (2013) Evolution of microstructure and changes of mechanical properties of CLAM steel after long-term aging. Mater Sci Eng A 586:253–258. doi:10.1016/j.msea.2013.08.025
Huang L, Hu X, Yang C, Yan W, Xiao F, Shan Y, Yang K (2013) Influence of thermal aging on microstructure and mechanical properties of CLAM steel. J Nucl Mater 443:479–483. doi:10.1016/j.jnucmat.2013.08.008
Kadoya Y, Dyson BF, McLean M (2002) Microstructural stability during creep of Mo- or W-bearing 12Cr steels. Metall Mater Trans A 33A:2549–2557. doi:10.1007/s11661-002-0375-z
Kim BC, Park SW, Lee DG (2008) Fracture toughness of the nano-particle reinforced epoxy composite. Compos Struct 86:69–77. doi:10.1016/j.compstruct.2008.03.005
Lapeña J, Garcia-Mazario M, Fernández P, Lancha AM (2000) Chemical segregation behavior under thermal aging of the low-activation F82H-modified steel. J Nucl Mater 283:662–666. doi:10.1016/S0022-3115(00)00276-2
Lee JS, Ghassemi-Armaki H, Maruyama K, Muraki T, Asahi H (2006) Causes of breakdown of creep strength in 9Cr–1.8W–0.5Mo–VNb steel. Mater Sci Eng A 428:270–275. doi:10.1016/j.msea.2006.05.010
Li Q (2006) Precipitation of Fe2W Laves phase and modeling of its direct influence on the strength of a 12Cr-2W steel. Metall Mater Trans A 37A:89–97. doi:10.1007/s11661-006-0155-2
Panait CG, Bendick W, Fuchsmann A, Gourgues-Lorenzon A-F, Besson J (2010) Study of the microstructure of the Grade 91 steel after more than 100,000 h of creep exposure at 600 °C. Int J Press Vessels Pip 87:326–335. doi:10.1016/j.ijpvp.2010.03.017
Sawada K, Kubo K, Abe F (2001) Creep behavior and stability of MX precipitates at high temperature in 9Cr-0.5Mo-1.8W-VNb steel. Mater Sci Eng A 319–321:784–787. doi:10.1016/S0921-5093(01)00973-X
Sawada K, Taneike M, Kimura K, Abe F (2003) In situ observation of recovery of lath structure in 9 % chromium creep resistant steel. Mater Sci Technol 19:739–742. doi:10.1179/026708303225010696
Schäfer L (2000) Tensile and impact behavior of the reduced-activation steels OPTIFER and F82H mod. J Nucl Mater 283–287:707–710. doi:10.1016/S0022-3115(00)00115-X
Sha W, Ye A, Malinov S, Wilson EA (2012) Microstructure and mechanical properties of low nickel maraging steel. Mater Sci Eng A 536:129–135. doi:10.1016/j.msea.2011.12.086
Thomas Paul V, Saroja S, Vijayalakshmi M (2008) Microstructural stability of modified 9Cr-1Mo steel during long term exposures at elevated temperatures. J Nucl Mater 378:273–281. doi:10.1016/j.jnucmat.2008.06.033
Wang W, Yan W, Sha W, Shan Y, Yang K (2012) Microstructural evolution and mechanical properties of short-term thermally exposed 9/12Cr heat-resistant steels. Metall Mater Trans A 43A:4113–4122. doi:10.1007/s11661-012-1240-3
Yang C, Yan W, Wang W, Shan Y, Yang K, Wu Y (2011) Changes of microstructure and mechanical property of the CLAM steel after long term aging at 600 °C. Acta Metall Sin 47:917–920. doi:10.3724/SP.J.1037.2011.00156
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Yan, W., Wang, W., Shan, Y., Yang, K., Sha, W. (2015). Thermal Ageing of Heat-Resistant Steels. In: 9-12Cr Heat-Resistant Steels. Engineering Materials. Springer, Cham. https://doi.org/10.1007/978-3-319-14839-7_6
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DOI: https://doi.org/10.1007/978-3-319-14839-7_6
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