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采用热模拟方法，对ＥＨ３６ＭＯＤ钢焊接热影响区粗晶区（ＣＧＨＡＺ）的相变超塑性及其对疲劳寿命的影响进行了研究。研究结果证明：（１）采用热作用与拘束位移的方法，在模拟ＣＧＨＡＺ中确实存在着相变超塑性现象；（２）该超塑性应变值为１．０％时，其ＣＧＨＡＺ的疲劳寿命比无相变超塑性的提高了１９％；（３）微观分析表明，前者Ｍ—Ａ组元的形态为长条状与块状的混合体，其分布为铁素体（Ｆ）基体包围Ｍ—Ａ组元和Ｍ—Ａ组元包围Ｆ基体的两种并存特征，而后者Ｍ—Ａ组元的形态呈单一的长条状，其分布仅为Ｍ—Ａ组元包围Ｆ基体；（４）Ｆ包围Ｍ—Ａ属软相包围硬相，在疲劳断裂过程中Ｆ基体内因滑移受阻所产生的微区应力小于Ｍ—Ａ包围Ｆ的，从而减慢了疲劳裂纹扩展速率，提高了疲劳寿命。
The phase transition superplasticity of CGHAZ and its influence on the fatigue life of EH36MOD steel were studied by means of thermal simulation. The results show that: (1) The phase-change superplasticity does exist in simulated CGHAZ by using thermal action and restrained displacement; (2) When the superplastic strain value is 1.0%, the fatigue life ratio of CGHAZ (3) The microscopic analysis shows that the morphology of the former M-A component is a mixture of long and lumpy forms, the distribution of which is that the ferrite (F) matrix surrounds the M- A component and M-A component enclose two kinds of co-existence characteristics of F matrix, while the latter M-A component has a single strip shape, its distribution is only surrounded by M-A element F matrix; (4) F surrounded by M-A soft phase surrounded by the soft phase, the F-matrix in the fatigue fracture process due to slip generated by the micro-zone stress is smaller than M-A surrounding F, thus slowing the fatigue crack growth rate and improve fatigue life.