Characteristics and formation mechanism of sidewall pores in NG-GMAW of 5083 Al-alloy
Characteristics and formation mechanism of sidewall pores in NG-GMAW of 5083 Al-alloy
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DOI：
10.1016/j.jmatprotec.2016.07.032
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发表时间：
2016-12
影响因子：
6.3
通讯作者：
Chenxiao Zhu;Xinhua Tang;Yuan He;F. Lu;H. Cui
中科院分区：
文献类型：
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作者：
Chenxiao Zhu;Xinhua Tang;Yuan He;F. Lu;H. Cui
对5083铝合金厚板进行了窄间隙熔化极气体保护焊焊接试验，分析了焊接气孔的大小和分布特征。研究发现，大气孔主要出现在窄间隙坡口侧壁附近的焊缝区。其数量和尺寸随着焊接电流的增大和/或焊接速度的降低而沿着增大，这与铝合金常规GMAW焊接完全不同。通过扫描电镜和能谱分析，发现氢是气孔形成的主要原因。窄间隙焊缝侧壁气孔的形成与坡口形式、熔池形状及其凝固行为密切相关，并通过偏光观察和EBSD分析得到了验证。在窄间隙焊接条件下，避免侧壁气孔和侧壁未熔合的最佳工艺参数为175 A和5 mm/s。
Narrow-gap gas metal arc welding was carried out on thick plate of 5083 Al-alloy, and the characteristics of welding pores were analyzed in terms of their size and distribution. The large pores were found to occur frequently in the weld zone adjacent to the sidewalls of narrow gap groove. Their amount and size increased along with increasing welding current and/or decreasing travel speed, which was totally different from conventional GMAW of aluminum alloy. The hydrogen was found to be the main cause to the pores by using SEM and EDS analysis. The formation of sidewall pores in narrow-gap weld beads were greatly related to the groove type, the shape of molten pool and its solidification behavior, and it was verified by polarization observation and EBSD analysis. The optimized parameters for avoiding sidewall pores and lack of sidewall fusion were 175 A and 5 mm/s in the narrow-gap welding of given aluminum alloy.