摘要:
用热模拟方法研究了WB36钢(15NiCuMoNb5)临界再热粗晶区(IRCGHAZ)组织特征及性能,分析组织转变过程及M-A组元形成原因,揭示了IRCGHAZ脆化机理。结果表明,IRCGHAZ保持粗大的板条状马氏体组织特征,形成了密集的M-A组元,其中条状M-A组元分布于马氏体板条间,而在原始奥氏体晶界形成链状M-A组元。与一次粗晶区(CGHAZ)、二次粗晶区及过临界再热粗晶区(SCCGHAZ)相比,IRCGHAZ的韧性最低,它将导致接头的局部脆化现象。IRCGHAZ脆化的主要原因是存在于晶内的条状M-A组元,而不是分布于晶界的粒状M-A组元,这是由于条状M-A组元比颗粒状M-A组元更容易引起解理断裂。
Abstract:
Microstructures and properties in the intercritical reheated coarse-grained heat-affected zone (IRCGHAZ)of WB36 (15-NiCuMoNb5)steel were studied by means of thermal simulation.In particular, the forming of M-A constituent in the IRCGHAZ and its influence on the toughness were investigated.Experimental results show that the coarsing lath martensite (ML)is retained in the IRCGHAZ, however, a great deal of M-A constituents are formed in IRCGHAZ compared with the coarse grain heat-ffected zone (CGHAZ), with elongated M-A constituents distributed at ML boundaries within the prior austenite grain and necklace-like blocky M-A constituents along the prior austenite grain boundaries.The toughness of IRCGHAZ is the lowest compared with that of the CGHAZ, the second CGHAZ and SCCGHAZ, which led to the local brittleness zone in HAZ.The loss in impact value of the IRCGHAZ was due to the formation of elongatedM-A constituents in the interior of the grains, but not related to the formation of necklace-like M-A constituent along the prior austenite grain boundary region.
百度学术
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