去应力退火对不同焊接电流下Q235钢焊接接头组织和性能的影响

Effects of stress relief annealing on microstructure and properties of Q235 steel weld joints under different welding currents

采用金相观察、硬度测试、冲击和拉伸等试验,研究了去应力退火对不同焊接电流下Q235钢焊件的组织性能的影响,并对相关影响因素进行了讨论。结果表明,随焊接电流从155 A增加到170 A,焊接接头各特征区的显微组织粗化,硬度下降;去应力退火对焊件的显微组织无明显影响,但硬度降低;且焊接电流越大,焊接接头退火前后的硬度差越大。无论是否退火,焊接接头的强度、塑性和冲击韧性均在160 A电流的焊接条件下出现最大值。小电流焊接接头的退火对塑性和冲击韧性的改善比大电流焊接接头的退火更有效。

Effects of stress relief annealing on microstructure and properties of Q235 steel weld joints under different welding currents are investigated and the relevant factors are discussed using metallographic observation, hardness measurement, tension and impact tests. The results indicate that with the welding current increasing from 155 A to 170 A, the microstructure of weld bead characteristic zones becomes coarse, and hardness reduces. The stress relief annealing shows no significant effect on microstructure of weld joints, but decreases hardness, and the larger the welding current is, the larger the difference of hardness value of the weld joint before and after annealing is. The tensile strength, plasticity and impact toughness of weld joints, whether annealing or not, reach the maximum values in the welding current of 160 A. The improvement of annealing of the weld joint in a small welding current on impact toughness and plasticity is more effective than that in a large welding current.