摘要
通过试验研究了S690Q高强钢对接节点的焊后性能。利用手工电弧焊焊接了3个厚度为8mm的S690Q高强钢对接节点,焊接过程中对3个节点分别采用不同的焊接热量。在微观层面上,用微观结构测试和微观硬度测试研究焊接对于节点的影响;在宏观层面上,通过拉伸试验研究焊接对于节点力学性能的影响。微观结构测试结果表明,S690Q高强钢的主要微观结构是回火马氏体。焊接后,在粗晶热影响区会转化为粒状贝氏体,在细晶热影响区会转化为铁素体和渗碳体,在回火区部分回火马氏体会分解成铁素体。基于硬度测试结果,可以在热影响区内发现软化层的存在,软化层与母材相比具有较低的硬度。此外,热影响区的宽度也随着焊接热量的升高而增大。拉伸试验表明,焊接对于S690Q高强钢节点的强度具有劣化作用,这主要是由焊接过程中形成的软化层造成的。所有测试节点的失效位置均位于热影响区,而且随着焊接热量的升高,强度的劣化现象也变得越来越严重。
In this study,we investigated the post-welding behaviour of S690 Qhigh strength steel butt joints experimentally.Three S690 Qhigh strength steel butt joints were welded with 8 mm thickness plate by shield metal arc welding with different welding heat inputs.Microstructure observation and micro-hardness test of heat-affected zone were employed to reveal the welding influence on the joints at the micro level,and tensile test of S690 Qhigh strength steel butt joints showed the welding impact at the macro level.The microstructure test indicated that the main microstructure of the S690 Qhigh strength steel was tempered martensite and was transformed to granular bainite in the coarse-grained heat-affected zone and to ferrite and cementite in the fine-grained heat-affected zone after welding of the joints.In the tempering zone,some of the tempered martensite decomposed to ferrite.Based on the hardness test results,it can be observed there is a soft layer in the heat-affected zone with lower hardness compared with the base material.In addition,the width of the heat-affected zone increased in the joint welded with higher heat input.The subsequent tensile test showed that the formation of a soft layer directly impairs the tensile behaviour of S690 Qhigh strength steel butt joints,and the strength deterioration becomes more serious with the increase of the welding heat input.
作者
周诚彬
陈成
赵明善
李子敬
冯达清
CHIEW Sing Ping;CHEN Cheng;ZHAO Ming Shan;LEE Chi King;FUNG Tat Ching(Singapore Institute of Technology,Singapore138683,Singapore;Nanyang Technological University,Singapore 639798,Singapore;University of New South Wales,Canberra,Australia)
出处
《土木与环境工程学报（中英文）》
CSCD
北大核心
2021年第1期64-71,共8页
Journal of Civil and Environmental Engineering
基金
Regency Steel Asia Endowment Fund at Nanyang Technological University。
关键词
高强钢
对接节点
微观结构
硬度
拉伸性能
high strength steel
butt joint
microstructure
hardness
tensile behavior
