焊后热处理对GH4169合金闪光焊接接头组织与性能的影响

Influence of Post-Weld Heat Treatment on Microstructure and Mechanical Properties of GH4169 Alloy Flash Butt Welded Joint

以GH4169高温合金闪光焊接件为研究对象,研究了热处理对焊缝试样的组织与力学性能的影响规律。结果表明,在焊接热量的作用下强化相γ′′、γ′发生回溶,致使焊接区的强度、硬度均明显低于基体。通过固溶处理后基体的强度降低到和焊缝试样一致,可实现拉伸变形过程中焊接区与基体的均匀变形。对焊缝试样在固溶前和固溶后进行1.2%拉伸塑性变形,经过时效处理(720℃/8 h (60℃/h)-620℃/8 h AC (空冷))后发现,少量塑性变形对其力学性能几乎没有影响。经固溶时效处理后焊缝试样抗拉伸强度指标与基体材料相比变化不大,但塑性指标低于基体试样,这与其热影响区存在粗大晶粒有关。

The influence of post-weld heat treatment on microstructure and mechanical properties of flash butt welded GH4169 alloy were investigated.Experimental results indicate that the redissolution happens to the strengthening phase γ″and γ′under the welding heat,so that the strength and microhardness of the welding zone are lower than those of the base metal (BM).After solid solution treatment,the strength of the BM reduces to the same as that of the weldments,and the uniform deformation between the welding zone and the BM can be realized during tensile deformation.The 1.2%tensile plastic deformation was carried out before or after solid solution on the weldments, after completing aging heat treatment (720℃/8h (60℃/h)-620℃/8h AC (air cooling)),the tensile results show that a small amount of plastic deformation has little effect on its mechanical properties.After solution-aging treatment,the tensile strength of the pre-deformation weldments is similar to that of the BM,but the plastic index is lower,which is related to the coarse grains in the welding zone.