摘要
目的针对双相不锈钢激光焊接接头两相比例失衡的问题,研究双相不锈钢2205激光焊接接头组织和性能。方法采用Disk6002碟片激光器对2205双相不锈钢进行激光焊接,通过在纯氩气保护气中添加体积分数为60%的氮气,向熔池中过渡氮元素,以提高焊缝中的奥氏体含量;采用金相显微镜、电子背散射衍射技术、电子探针X射线显微分析仪、显微硬度仪和上海辰华CHI760E电化学工作站等手段,对激光焊接接头表面组织、元素含量、显微硬度和耐腐蚀性能进行表征和测试。结果与纯氩气保护焊接接头相比,当在保护气中添加60%(体积分数,下同)的氮气后,奥氏体相体积分数达到39.89%,提升了25.94%,奥氏体中氮元素的质量分数达到0.679%时,氮元素的质量分数提升了0.196%,焊缝中奥氏体显微硬度为307.4HV,铁素体显微硬度为298.9HV,极化曲线腐蚀电流密度升高,阻抗弧半径减小。结论在保护气中添加60%的氮气后,激光焊接接头中奥氏体的体积分数提升,增加的奥氏体组织以晶内奥氏体为主,并且更多的氮元素进入到奥氏体相中,焊缝中的奥氏体和铁素体硬度略有升高,耐蚀性和钝化膜稳定性有所下降。
The work aims to study the microstructure and properties of 2205 duplex stainless steel joint by laser welding,so as to solve the problem of unbalanced proportion of two phases in the joint.Trumpf Disk 6002 laser was used to weld the 2205 duplex stainless steel.The content of austenite in weld was increased by transferring nitrogen to weld pool with adding 60%ni-trogen to the shielding gas.The metallographic microscopy,electron backscatter diffraction,electron probe X-ray microanalyzer,microhardness tester,and Shanghai Chenhua CHI760E electrochemical workstation were adopted to characterize and test the surface microstructure,element content,microhardness and corrosion resistance of laser welded joint.Compared with pure ar-gon gas shielded joint,the austenite phase content reached 39.89%after 60%nitrogen was added to the shielding gas,which in-creased by 25.94%.The nitrogen element content in austenite reached 0.679 wt.%,increasing by 0.196 wt.%.The microhardness of austenite in welded joint increased to 307.4HV,and the microhardness of ferrite increased to 298.9HV.The polarization curve indicated an increase in corrosion current density and a decrease in impedance arc radius.It is found that after 60%nitrogen is added to the shielding gas,the austenite content in the laser welded joint increases,and the increased austenite microstructure is mainly intragranular austenite.In addition,more nitrogen enters the austenite phase,the hardness of austenite and ferrite in the weld increases slightly,and the corrosion resistance and the stability of passive film decrease.
作者
徐永朝
李天庆
万永杰
李远航
王凯
XU Yong-chao;LI Tian-qing;WAN Yong-jie;LI Yuan-hang;WANG Kai(School of Materials Science and Engineering,Jiangsu University,Jiangsu Zhenjiang 212013,China)
出处
《精密成形工程》
北大核心
2023年第9期90-98,共9页
Journal of Netshape Forming Engineering
基金
国家自然科学基金(51605201)
江苏大学大学生创新创业训练计划(20231222)。
关键词
激光焊接
双相不锈钢
焊缝
氮
奥氏体
laser welding
duplex stainless steel
weld
nitrogen
austenite
