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为了分析国产改良型T23钢粗晶热影响区(CGHAZ)再热裂纹的开裂特征,在Gleeble-3500热力耦合试验机进行了CGHAZ的制备和STF(strain to fracture)试验,获得了不同试验温度下的断裂试样,并采用SEM及EBSD在断口剖面试样上展开微区的特征分析。结果表明:空洞在晶界M3C上形核,随着应力松弛,空洞增加并聚集形成微裂纹。不同试验温度下,空洞形核和裂纹扩展时,晶界及晶内应变的集中程度非常不同,反映了它们各自塑性变形能力的不同,是造成不同温度下T23钢CGHAZ再热裂纹开裂特征不同的原因。
In order to analyze the cracking characteristics of reheat cracks in CGHAZ of domestic modified T23 steel, CGHAZ and STF (strain to fracture) tests were carried out on Gleeble-3500 thermal coupling tester, Of the fracture samples, and the use of SEM and EBSD in the fracture profile of the micro-zone analysis of the characteristics of the sample. The results show that the voids nucleate at the grain boundary M3C, and with the relaxation of stress, the voids increase and aggregate to form microcracks. At different test temperatures, the concentration of nucleation and intragranular strain is very different at cavity nucleation and crack propagation, reflecting their different plastic deformation ability, which is caused by the different crack initiation characteristics of CGHAZ reheat cracking at different temperatures the reason.