热模拟法研究07MnNiCrMoVDR钢再热裂纹敏感性

Study on Reheating Crack Susceptibility of 07MnNiCrMoVDR Steel by Thermo-mechanical Simulator

利用热模拟试验机模拟出了07MnNiCrMoVDR钢不同的热影响区组织,并对模拟组织进行高温缓慢拉伸试验,采用断面收缩率为判据,研究了该钢种的再热裂纹敏感性,验证了敏感温度下再热裂纹的实际存在。结果表明,采用小热输入焊接时,该钢种对再热裂纹不敏感;大热输入情况下,其再热裂纹敏感温度在600℃左右;实际焊接结构热处理应避开敏感温度区间以防止产生再热裂纹。

The HAZ （heat affected zone） structure of 07MnNiCrMoVDR steel was acquired by thermo-mechanical simulator. The tensile tests at very low strain rate were done to those specimens in order to investigate the reheat cracking susceptibility of the steel. The criterion of valuation is the reduction of area. The existing of reheating cracking was proved by the presence of cracking at sensitive temperature. The results indicate that the steel is insensitive to reheat cracking while welding with low energy input. However, it is sensitive to the type of cracking while welding with high energy input. The sensitive temperature is 600C. The heat treatment of welding structure should avoid the sensitive temperature range in order to prevent the reheating cracks.