氧化物弥散强化MGH956合金TIG焊缝气孔问题分析

Study on pores in TIG welding of oxide dispersion strengthened(ODS) alloys MGH956

摘要: 通过X射线探伤和金相分析相结合的方法,对氧化物弥散强化(ODS)合金MGH956的TIG焊接气孔的产生机理、分布、数量及焊接工艺参数的影响进行了研究.结果表明,气孔的产生与ODS合金本身的制造工艺特点、弥散氧化物颗粒和焊缝组织有关;在焊缝的边缘发现许多小泡;焊缝气孔在焊缝两侧的熔合线附近呈链状分布,这是由熔池各部位的特点、焊接接头的组织和温度分布共同作用形成的;调整焊接工艺参数会影响焊缝气孔量的变化,较小的热输入,如小电流、快速度和适合的脉冲频率能在一定程度上减少焊缝气孔量.

Abstract: The formation mechanism,distribution,number of pores and the effect of welding parameters in TIG welding of MGH956 alloy sheet were studied by X-ray method and metallurgical analysis. The results show that pores in MGH956 alloy TIG welds is related to fabrication technology of the alloy MGH956 and the microstructures in the weld. Pores are inclined to distribute linkly near the fusion line,due to the characteristics in the different sections of weld pool,the microstructure and distribution of temperature in the weld joint. Optimizing welding parameters can affect the number of pores. Low heat input such as low current,high speed and appropriate pulse frequency can reduce the number of pores to some extent.