Macrostructural and microstructural features of 1 000 MPa grade TRIP steel joint by CO2 la

Macrostructural and microstructural features of 1 000 MPa grade TRIP steel joint by CO2 laser

welding

作者：Wang Wenquan;Sun Daqian;Kang Chungyun

作者机构：School of Materials Science and Engineering, Jilin University, Changchun, 130025;School of Materials Science and Engineering, Jilin University, Changchun, 130025;Department of Material Science and Engineering,Pusan National University, Pusan 609-735, Korea 来源：中国焊接 ISSN：1004-5341 年：2008 卷：017 期：002 页码：1-7 页数：7 中图分类：TG4 正文语种：chi

关键词：CO2 laser welding, transformation induced plasticity steel, macrostructure, microstructure

摘要：Bead-on-plate CO2 laser welding of 1 000 MPa grade transformation induced plasticity (TRIP) steel was conducted under different welding powers, welding speeds and shield gases. The macrostructural and microstructural features of the welded joint were investigated. The increase of welding speed reduced the width of the weld bead and the porosities in the weld bead resulting from the

different flow mode of melted metal in weld pool. The decrease of welding power or use of shield gas of helium also contributed to the reduction of porosity in the weld bead due to the alleviation of induced plasma formation, thus stabilizing the keyhole. The porosity formation intimately correlated with the evaporation of alloy element Mn in the base metal. The laser welded metal had same martensite microstructure as that of water-quenched base metal. The welding parameters which increased cooling rate all led to fine microstructures of the weld bead.