异种钢恒温超塑焊接头特征区域分析

Analysis of characteristic zones of isothermal superplastic welded joint of heterogeneous steels

通过对40Cr/T10A钢试样及试样待焊面表层分别实施盐浴加热循环淬火、高频淬火及激光淬火的组织超细化预处理,借助于金相及电子显微分析技术,系统研究了异种钢恒温超塑焊接头区显微组织形貌、超塑性微观结构特征及其形成特点,提出了恒温超塑焊接头组织特征区域的构成模型。结果表明,恒温超塑焊接合面处存在着明显扩散行为,其接头的特征区域可分为界面超细晶区、过渡区、母材区;经超细化预处理的接头区在恒温超塑焊过程中呈现出典型的超塑性微观结构特征。

Through such ultra-fining-pretreatment of 40Cr and T10A steels as salt-bath cyclic quenching, high frequency hardening and laser hardening, the microstructure appearance, the superplastic microstructure characteristic and their forming characteristic of isothermal superplastic welded joint of heterogeneous steels are systematically studied by the metallurgical microscope and electron microscope. And the characteristic zone forming model of the joint is established. The experimental results indicate that it occurs obviously the diffusive behavior in the isothermal superplastic welded interface and the characteristic zones of the joint are divided into three zones which are respectively ultra-fined grain zone of interface, transition zone and base metal zone. The microstructure of the welded joint through ultra-fining pretreatment presents the typical superplastic microstructure characteristic in the isothermal superplastic welding process.