焊后热处理对P92钢焊接接头显微组织和力学性能的影响

采用光学金相显微镜和力学性能测试等方法,研究了电阻履带式和中频感应两种不同的焊后热处理方法对P92钢焊接接头显微组织和力学性能的影响。结果表明:中频感应处理下的焊缝组织较为细小,马氏体板条界面变得更加模糊;焊接接头各层母材、热影响区及焊缝硬度值分布均匀,内、中和外层的硬度差值较小;焊缝及热影响区冲击吸收能量沿壁厚方向分布较为均匀,且均高于P92母材标准要求值。因而,中频感应加热法不仅可以很好地改善焊缝组织,而且在壁厚方向上,可以使焊缝韧性等力学性能更加均匀。 

Effect of post-weld heat treatment on microstructure and mechanical properties of P92 steel welded joint

Effects of resistance crawler-type heating and medium frequency induction heating on microstructure and mechanical properties of P92 steel welded joints were studied by means of optical metallographic microscope and mechanical properties test. The results show that the microstructure of the welded joint is fine and the interface of martensite lath becomes more fuzzy under medium frequency induction heat treatment. The microhardness values of the base metal,heat affected zone and weld seam of each layer of the welded joint are evenly distributed,and the difference among the microhardness of the inner layer,the middle layer and the outer layer is small. The impact absorption energy values of weld seam and heat affected zone are distributed evenly along the wall thickness direction,and are higher than the standard values of P92 base metal. Therefore,medium frequency induction heat treatment method not only improves the weld microstructure,but also makes the weld impact toughness value and other mechanical properties more uniform in the direction of wall thickness.