Study on microstructure and fatigue properties of the plug welding joint of different weathering resistant steels

CHEN Liyuan; MIAO Jia; MU Yunping; HAO Xiaowei; ZONG Huanxu

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Study on microstructure and fatigue properties of the plug welding joint of different weathering resistant steels
Vol. 48, Issue 7, Pages: 67-71(2018)
Published：2018
DOI：
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DOI：

CHEN Liyuan, MIAO Jia, MU Yunping, et al. Study on microstructure and fatigue properties of the plug welding joint of different weathering resistant steels[J]. Eletric Welding Machine2018, 48(7): 67-71. DOI：

摘要

通过显微组织分析、硬度试验和脉动拉伸疲劳试验

研究Q310NQL2与Q345NQR2耐候钢塞焊接头的组织和性能。结果表明:采用ER50-G碳钢焊丝焊接时

塞焊接头熔核区组织为珠光体+铁素体

过热现象导致出现魏氏组织

热影响区珠光体片层粗大;熔核区硬度最高

热影响区硬度有所下降

但软化现象不明显。脉动拉伸疲劳试样断口位于薄板侧熔核区根部

疲劳断裂的主要原因是此处的脆性组织和应力集中。

Abstract

Through the analysis of the microstructure

hardness test and pulsating tensile fatigue test

study the microstructure and properties of the plug welding joint of Q310NQL2 and Q345NQR2 corrosion resistant steels. The results show that

when the ER50-G mild steel welding wire is used for plug welding process

the structure of plug weld nugget zone is pearlite

ferrite and Widmanstatten structure. In the heat affected zone the pearlite become larger because of overheating. The hardness of nugget zone is the highest in the whole joint

and the hardness of heat affected zone relatively decreased

but the softening phenomenon is not obvious. The fracture of pulsating tensile fatigue specimen is located at the root of the side nugget zone of thin plate. The brittle structure and stress concentration here are the main causes of fatigue fracture.