以Q345钢成分为基础,设计并冶炼了不同Cr含量(0.36%、0.55%及0.70%,质量分数)的试验钢,通过焊接热模拟试验研究Cr含量对低合金结构钢焊接粗晶热影响区的影响。结果表明,焊接热模拟后,试验钢CGHAZ组织均为贝氏体。Cr含量为0.70%时,晶粒明显粗大,贝氏体条片较细且长,具有明显的方向性,材质韧性恶化;随Cr含量增加,试验钢CGHAZ冲击吸收能量降低,断口晶状断面率增大,硬度增大。从焊接性能角度考虑,Cr含量应控制在0.55%左右。 Based on the composition of Q345 steel, the test steels with different Cr contents (0.36%, 0.55% and 0.70%, mass fraction) were designed and smelted. The effects of Cr content on the coarse grain heat affected zone Impact. The results show that the CGHAZ specimens are bainite after welding heat simulation. When the Cr content is 0.70%, the grains are obviously coarse, the bainite strip is thin and long, with obvious directionality, the material toughness is deteriorated. The CGHAZ impact absorption energy decreases with the increase of Cr content, Increase, hardness increases. From the welding point of view, Cr content should be controlled at about 0.55%.