12Cr/30Cr2Ni4MoV异质接头低周疲劳性能

基于异种钢的焊接冶金技术理念的特定条件，根据焊接工况的实际应用与试验研究的验证结果，针对大型中碳铸钢部件的补焊，提出了优化焊接材料与工艺的实战技术组合方案。采用可以显著改进焊接性（抗冷裂纹和热裂纹）的Mn，Ni奥氏体高合金钢的专用焊丝（Cr20Ni10Mn7Si-ZG），免除了焊前预热和焊后热处理（完全冷焊），并可获得优良的焊缝力学性能；通过在坡口内预制焊接结构补强的壳体结构，改善了焊接热循环中的热场分布和焊接结构的受力条件，提高了焊接结构的抗疲劳性能；预制由内置钢腹板所构建的三维刚性骨架体系，通过无间隙镶嵌的刚性支撑，无差别地抵消焊接填充金属冷凝时所产生的垂直于坡口壁的收缩应力，可最大化地控制焊接变形量和降低裂纹扩展速率。

Simulating the residual deformation of thin-plate butt weldments without wire filling by contact mode

Based on specific conditions of welding metallurgy technology concept of dissimilar steels, according to actual application of welding conditions and verification results of experimental research and aiming at repair welding of large medium carbon cast steel parts, a practical technology combination scheme of optimizing welding materials and processes was put forward. Special welding wires (Cr20Ni-10Mn7Si-ZG) for Mn, Ni austenitic high alloy steel that could significantly improve weldability (resistance of cold crack and hot crack) were used to avoid pre-welding and post-welding heat treatment (complete cold welding) and obtain excellent mechanical properties of weld. By prefabricating welded structural reinforcement of shell structure in the groove, heat field distribution in welding thermal cycle and stress condition of welded structure were improved, and fatigue resistance of welded structure was improved. The prefabricated three-dimensional rigid skeleton system constructed by built-in steel web indiscriminatingly offset shrinkage stress perpendicular to groove wall generated by condensation of welding filling metal through rigid support without gaps, which could maximize control of welding deformation and reduce crack growth rate.