本文研究了09CuPTiRE热轧钢板焊接热裂纹的形成机制。结果表明:其焊裂性质为高温低塑性裂纹,主要原因为组织异常,异常组织中的沿晶不连续网状碳化物是造成晶界弱化的主要原因。焊接时在热影响区内交变应力的作用下,裂纹自铁素体和沿晶碳化物交界处萌生,扩展,产生焊接热裂纹。在950℃保温两小时后缓冷可避免产生热裂纹。 This paper studies the formation mechanism of 09CuPTiRE hot-rolled steel welding hot cracks. The results show that the welding crack is of high temperature and low plasticity. The main reason is the abnormal microstructure. The discontinuous network carbides in the abnormal structure are the main reasons leading to the grain boundary weakening. Welding in the heat affected zone under the action of alternating stress, the cracks from the ferrite and the intergranular carbide at the junction of initiation, expansion, resulting in welding hot cracks. Slowly cooled at 950 ° C for two hours to avoid hot cracking.