中文摘要：

利用Gleeble-3500热力模拟试验机制备T23钢焊接接头中粗晶热影响区和不同二次热循环的再热粗晶热影响区,并进行STF（Strain-to-fracture）试验。结果表明,粗晶区经历1 350℃或780℃二次热循环后,仍保持粗晶热影响区的粗大晶粒、笔直的晶界形貌以及高再热裂纹敏感性,断面收缩率低于5%。粗晶区经历了880℃、950℃或1 100℃二次热循环后,晶粒尺寸变小,晶界变曲折,断面收缩率分别为24.67%、16.6%和7.24%,再热裂纹敏感性降低。因此,合理调控二次热循环的峰值温度在A_（c1）~A_（c3）之间可以有效降低再热裂纹敏感性。

英文摘要：

The coarse-grained heat-affected zone （CGHAZ） and reheat coarse-grained heat-affected zone （reheat CGHAZ） ex- perienced different second thermal cycle of T23 steel were produced by a Gleeble-3500 thermo-mechanical simulator, and then strain to fracture （STF） tests were carried out. Results showed that CGHAZ experienced thermal cycle of 1 350 ℃ or 780 ℃ still had coarse grain, straight grain boundary configuration and high reheat cracking sensitivity, with a reduction of area of lower than 5%. CGHAZ experienced thermal cycle of 880 ℃, 950 ℃ or 1 100 ℃ had smaller grain size, zigzag grain boundary and low reheat crac- king sensitivity, and the reductions of area were 24. 67%, 16.6% and 7.24% respectively. Controlling the peak temperature of the second welding thermal cycle to the range of Ac1-Ac3 can reduce reheat cracking sensitivity.