基于纳米压痕技术的9%Ni钢接头组织及力学性能研究

Microstructure and Mechanical Performance of 9%Ni Steel Welded Joint Based on Nanoindentation Technology

以ENiCrMo-6镍基合金焊条为填充材料,对9%Ni钢母材进行了对接焊接试验。采用纳米压痕技术研究焊接接头母材、粗晶粒热影响区、熔合区和焊接中心区域各微区组织与力学性能的关系。通过拉伸试验来确定接头的薄弱区域。结果表明:接头具有良好的塑韧性。粗晶热影响区具有最高强度,富铬析出相Fe-Cr和Ni-Cr-Fe等分散在奥氏体基体上,板条间的逆变奥氏体基本消失。结合组织及力学性能分析发现裂纹起始于熔合区。

Taking the ENiCrMo-6 Ni based alloy electrode as the filler material, the butt welding test of 9%Ni steel base metal was carried out. Nanoindentation technology was used to study the relationship between the microstructure and mechanical properties of the base material, coarse grain heat-affected zone, fusion zone and welding center area of the welded joint. The weak area of the joint was determined through the tensile test. The results show that the joint has good plastic toughness. The coarse grain heat-affected zone has the highest strength, the chromium-rich precipitation phases Fe-Cr and Ni-Cr-Fe are dispersed on the austenite matrix, and the inverted austenite between the laths basically disappears. Combining the analysis of structure and mechanical properties, it is found that the cracks start in the fusion zone.