Influence of Multi-layer and Multi-pass TIG Welding Process on the High Strength Weld Metal Microstructure and Toughness

doi:10.3901/JME.2017.18.106

Abstract

Abstract: High strength weld metal with strength over 890 MPa are made using tungsten inert gas arc welding(TIG) with multi-layer and multi-pass process. The microstructure of the as-weld metals and reheated metals and charpy impact fracture surface is characterized with optical microscope(OM), scanning electron microscope(SEM), transmission electron microscope(TEM),and the influence of microstructure on weld metal toughness is analysed. The result shows that the as-weld metals are mainly composed of martensite and coalesced bainite, which is harmful to impact toughness. The reheated metals are mainly composed of finer temper martensite with column and coalesced bainite disappearing, which improves the weld toughness. The morphology of retained austenite turned from films into block due to the effect of reheat, with little contribution to the toughness.

Key words: microstructure, retained austenite, TIG multi-layer and multi-pass welding, toughness

CLC Number:

TG142

PENG Xingna, PENG Yun, PENG Xiankuan, CONG Xiangzhou. Influence of Multi-layer and Multi-pass TIG Welding Process on the High Strength Weld Metal Microstructure and Toughness[J]. Journal of Mechanical Engineering, 2017, 53(18): 106-112.

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