TWIP钢激光焊接接头的显微组织和力学性能

Microstructure and Mechanical Properties of Laser Welded Joint of TWIP Steel

研究了孪晶诱导塑性(TWIP)钢经3种不同工艺参数激光焊接后的焊接接头的显微组织和力学性能。结果表明:焊接接头焊缝区为全奥氏体组织,与母材相比,焊缝区的Mn含量略有降低;较大的焊接热输入可以保证焊缝的连续性,但也会导致焊缝组织粗大、粗晶区宽度增大;焊缝熔融区为树枝晶组织,热影响区含0.3~0.4mm宽的软化区和0.5~0.6mm宽的硬化区;焊接接头的最高抗拉强度和断后伸长率分别为900MPa和33%,约为母材的90%和50%。

Microstructure and mechanical properties of joints of the laser welded twinning induced plasticity (TWIP) steel at three categories of laser welding parameters was investigated. The results indicated that the weld area was a whole austenitic structure, as compared with the base metal, the Mn content in the weld area decreased slightly.The larger welding heat input can ensure the continuity of weld, however, it will also lead to coarser weld microstructure and larger coarse-grained zone width. The microstructure of fusion zone (FZ) was coarse dendrite grains, and the heat affected zone (HAZ) consisted of 0.3 mm to 0.4 mm wide softened zone and 0.5 mm to 0.6 mm wide hardened zone. The highest tensile strength and elongation of the welded joints were 900 MPa and 33% respectively, being about 90% and 50% that of the base metal.