TWIP钢激光和TIG焊接接头的组织和性能

Microstructure and Properties of Welded Joints of TWIP Steel Welded by Laser and TIG

采用激光焊和TIG焊分别对TWIP钢进行焊接,通过显微组织观察、拉伸试验及显微硬度测试对比研究了两种焊接接头的组织和性能。结果表明:激光焊的焊缝中心为细小的等轴晶,靠近熔合线的组织多为柱状晶,几乎看不到热影响区;TIG焊的焊缝组织为取向基本一致的柱状晶且晶粒较大,热影响区为粗大的奥氏体组织;激光焊接头拉伸试样在远离焊缝的母材处断裂,抗拉强度为560 MPa,伸长率为67%,断口为典型的韧性断裂;TIG焊接头断裂在热影响区,抗拉强度为460 MPa,伸长率为48%,断口表现为脆性断裂,塑性变形能力明显低于激光焊接头的;激光焊接头的平均显微硬度高于TIG焊接接头的。

Twinning induced plasticity （TWIP） steel was welded by laser welding and TIG welding. Microstructure and properties of welded joints were studied by microstructure observation, tensile test and microhardness test. The results show that grains in the welding line center by lasing welding were small and equiaxial, and microstructure near welding fusion line was columnar crystals, but the heat affected zone could hardly be recognized. The microstructure of TIG welding seam was columnar crystal with nearly consistent-oriented and the crystalline grains were large, and the heat affected zone displayed gross austenite structure. The lasing welding sample fractured in the matrix far from the welding line with tensile strength of 560 MPa and elongation of 67%, and showed typical ductile fracture. The TIG sample fractured in the heat affected zone with tensile strength of 460 MPa and elongation of 48%, and the fracture manifested as brittle fracture. The plastic deformation for TIG sample was clearly lower than lasing welding sample, and the average microhardness of welded joint by lasing welding was higher than TIG welded ioint.