消除应力回火对30CrMnSiNi2A真空电子束焊接头组织和力学性能的影响

针对30CrMnSiNi2A超高强度钢结构件真空电子束焊后消除应力回火工艺，开展了重复回火对锁底焊接接头最终热处理状态的组织与力学性能影响研究。试验结果表明，焊接零件分别经过一次、三次消除应力回火，其最终态拉伸性能与直接最终热处理30CrMnSiNi2A原材料相比有少量提升，同时焊缝的拉伸性能略高于母材；原材料、一次消除应力焊件、三次消除应力回火焊件终态显微组织均为板条状马氏体，除组织均匀性和马氏体形貌略微变化外，无显著的组织及成分差异；相比于母材的疲劳极限，一次消除应力回火接头疲劳极限降低了11%,三次消除应力回火接头疲劳极限降低了18%。

Effect of stress relief tempering on microstructure and mechanical properties of 30CrMnSiNi2A vacuum electron beam welded joint

Abstract: Aiming at the stress relief tempering process after vacuum electron beam welding of 30CrMnSiNi2A ultra-high strength steel structural parts, effect of repeated tempering on microstructure and mechanical properties of lock bottom welded joints in the final heat treatment state was studied.The test results showed that after once and thrice stress relief tempering, tensile properties of welded parts in the final state were slightly improved in comparison with the raw materials of 30CrMnSiNi2A after direct final heat treatment, and tensile properties of the weld were slightly higher than those of the base metal.The final microstructure of raw materials, once stress relief tempered weldments and thrice stress relief tempered weldments was strip martensite, and there was no significant difference in microstructure and composition except for slight changes in microstructure uniformity and martensite morphology.Compared with the fatigue limit of base metal, the fatigue limit of once stress relief tempered joint was reduced by 11%, and that of thrice stress relief tempered joint was reduced by 18%. Highlights:(1)Influence of stress relief tempering on tensile and fatigue properties of joints was mastered. (2)Combined with the microstructure analysis, the influence mechanism was studied.