Study on microstructure-toughness relationship in heat affected zone of EQ70 steel by laser-arc hybrid welding

被引：20

作者：

Bao, Liangliang ^{[1
,2
]}

Wang, Yong ^{[1
]}

Han, Tao ^{[1
]}

机构：

[1] China Univ Petr, Sch Mat Sci & Engn, Qingdao 266580, Peoples R China

[2] China Construct Ind & Energy Engn Grp Co Ltd, Nanjing 210000, Peoples R China

来源：

MATERIALS CHARACTERIZATION | 2021年 / 171卷 / 171期

基金：

中国国家自然科学基金;

关键词：

Heat affected zone; Microstructure; Toughness; Laser-arc hybrid welding; High strength low alloy steels; CLEAVAGE FRACTURE INITIATION; IMPROVED ETCHING TECHNIQUE; MECHANICAL-PROPERTIES; PROCESS STABILITY; GRAIN-BOUNDARY; STRENGTH; MARTENSITE; CONSTITUENTS; TRANSITION; JOINT;

D O I：

10.1016/j.matchar.2020.110788

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

The microstructures and toughness of the laser-arc hybrid welded joint of EQ70 steel were investigated by optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron back-scattered diffraction (EBSD), micro-shear test and Charpy impact test. The micro-shear toughness reduction and impact toughness reduction both occurred when the micro-zones traversed the coarse grained HAZ (CGHAZ) and inter-critically reheated coarse grained HAZ (ICCGHAZ). The CGHAZ were composed of lath martensite (LM), granular bainite (GB) and polygonal ferrite (PF). Necklace M-A constituents were distributed at the ICCGHAZ grain boundaries. The All-Euler maps showed that high angle boundaries (HABs) above 45 degrees can notably block the micro-cracks propagation. The block width was the effective grain size controlling the toughness. The increase of block width in CGHAZ and ICCGHAZ, together with the necklace grain boundary M-A constituents, both contribute to the toughness reduction.

引用

页数：11

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