焊接热输入对Q890D高强钢焊接接头力学性能及组织影响

Influence of Welding Heat Input on the Mechanical Property and Microstructure at Welded Joints of Q890D High-strength Steel

以三种不同焊接热输入20kJ／cm、17kJ／cm、14kJ／cm研究对Q890D高强钢焊接接头性能和组织的影响。研究表明：焊接热输入变化对焊接接头性能有一定的影响，热输入选择在17kJ／cm时焊接Q890D高强钢较为适宜。其焊缝组织为板条贝氏体＋粒状贝氏体；HAz过热区组织为板条马氏体；HAz细晶区组织为板条马氏体，呈细晶等轴状；HAZ不完全淬火区组织为细晶等轴状板条马氏体＋回火马氏体。

The influence of different welding heat inputs （20KJ/cm, 17KJ/cm and 14KJ/cm） on the properties and microstrueture at welded joints of Q890d high-strength steel is studied. The results shows that, the welding heat input has some effect on the properties of welded joints, and the welding heat input of 17KJ/cm during the welding of Q890D high-strength steel is proved to be the best choice. Its microstructure in weld zone is lath martensite ＋ granular bainite ; the mierostructure in HAZ overheated zone is lath martensite, keeping grain-refining and equiaxed; the microstructure in HAZ partial-quenched zone is grain-refining and equiaxed lath martensite ＋ tempered martensite.