中厚板低碳钢激光深熔焊接气孔形成特征研究  

Research on Porosity Formation of Medium Thick Plate of Mild Steel in Laser Deep Penetration Welding

作　　者：钟世杰 魏昕[1] 龚郡 汪永超 Zhong Shijie;Wei Xin;Gong Jun;Wang Yongchao(School of Electromechanical Engineering,Guangdong University of Technology,GuangzhouGuangdong 510006,China;Synergy Innovation Institute for Moclern Industries of GDUT&Dungyuati,Heyuan,Guangdong 517500,China;Synergy Innovation Institute of GDUT&Heyuan,Heyuan,Guangclorifr 517025,China)

机构地区：[1]广东工业大学机电工程学院,广东广州510006 [2]东源广工大现代产业协同创新研究院,广东河源517500 [3]河源广工大协同创新研究院,广东河源517025

出　　处：《应用激光》2021年第4期697-703,共7页Applied Laser

基　　金：广东省科技计划项目(2018B090902003)。

摘　　要：为了研究熔透和未熔透两种状态下低碳钢气孔形成特征,试验控制保护气种类与表面氧化物两个条件,采用激光功率3 100 W、焊接速度10 mm/s,分别对6 mm和8 mm厚的低碳钢进行平板对接焊,观察焊缝纵断面气孔分布,使用电子显微镜观察其形貌及EDS分析孔壁元素,并讨论气孔产生的原因。另外,还设计熔透性试验,研究激光功率以及焊接速度对气孔的影响。结果表明:熔透状态的焊缝形成气孔数、气孔率远远小于未熔透状态的;CO2保护气以及表面氧化物在焊接过程中都有抑制气孔产生的作用;未熔透状态下出现较多的工艺类气孔与冶金类气孔,熔透状态下焊缝形成的气孔则以圆形H2孔为主,其中冶金类气孔的内壁与焊缝附近元素含量相差较大,主要由于熔池内发生了冶金反应导致。进一步的熔透性试验表明:激光功率越大,气孔数越少,气孔率先减小后增加;随着焊接速度的增加,气孔数增加,但气孔率呈现先降低后增加的趋势。In order to study the characteristics of porosity formation of mild steel under two conditions of penetration and non-penetration, mild steel(6 mm and 8 mm thick) was welded with a welding power of 3 100 W and a welding speed of 10 mm/s, respectively, under the control of two parameters which is shielding gas and surface oxide. The method of cutting cross-section of weld seam was observe the morphology and location of porosity in the weld by scanning electron microscope(SEM).EDS point scanning analysis in the wall of porosity and discuss the causes of porosity formation. In addition, the permeability experiment was designed to study the influence of laser power and welding speed on the porosity. The research results show that the number and rate of porosity in the condition of penetration are far less than those in the condition of non-penetration. The shielding gas of CO2 and the surface oxides can inhibit the pores in the welding process. Under the condition of non-penetration, the porosity formation in the weld are metallurgical pores and process pores. But in the condition of penetration, the pores of the weld are round H2 pores. The content of chemical elements of metallurgical pores in the porosity and weld zone is greatly different, which is mainly caused by metallurgical reaction in the molten pool. Moreover, The higher the laser power, the less the number of porosity, but the rate of porosity first decreased and then increased. With the increase of weld velocity, the number of porosity increased, but the rate of porosity decreased first and then increased.

关 键 词：激光技术 激光深熔焊接 气孔 低碳钢 

分 类 号：TG456.[金属学及工艺—焊接]