交直流混合VPPA特性及铝合金立焊工艺  

Vertical welding of aluminum alloy during variable polarity plasma arc welding process with AC-DC mixing output current

作　　者：韩永全[1] 洪海涛[1] 郭龙[1] 姚青虎[1] 

机构地区：[1]内蒙古工业大学材料成型自治区重点实验室,呼和浩特010051

出　　处：《焊接学报》2013年第9期59-62,116,共4页Transactions of The China Welding Institution

基　　金：教育部新世纪优秀人才资助项目(NCET-10-0908);内蒙古科技厅高新技术项目(NK2011-10)

摘　　要：厚板铝合金变极性等离子弧(VPPA)穿孔立焊工艺中,由于焊接电流大,长时间焊接时钨极的烧损量大,严重影响厚板大结构自动焊接质量.为此提出了通过交直流混合输出减少钨极烧损,同时提高焊接质量的新型铝合金变极性等离子弧穿孔焊接方法.该方法在保证氧化膜清理的前提下,减小了因反极性时间过短电弧在极短时间内两次过零造成的等离子弧力下降和过大的感应电动势对开关器件的损害.其次交直流混合输出电弧具有低频调制效果,起到熔池振荡、细化晶粒的作用.在实现交直流混合VPPA软硬件功能基础上研究了交直流混合VPPA等离子弧力学特性、焊接过程稳定性及焊缝成形机理.通过对焊缝显微组织及焊缝成形检验发现,交直流混合输出时焊缝晶粒细化,焊缝成形美观,实现了减少钨极烧损和提高焊缝质量双重目标.The quality of automatic keyhole-mode vertical welding of thick aluminum alloy plate with variable polarity plasma arc welding process is severely affected by the large welding current and burning of tungsten electrode during long-period working. A new method was proposed with AC-DC mixing output current to reduce the burning rate of tungsten electrode and improve the welding quality. In ensuring cleanup of oxide film,this method could decrease the decline of arc force caused by twice crossing zero welding current within a very short time and decrease the damage to switching devices from the excessive induced electromagnetic force. Meanwhile,the mixing output current could realize welding pool oscillation and grain refinement by the low frequency modulation. The mechanical properties of plasma arc,welding process stability and mechanism of weld formation were also investigated. After examination of the weld microstructure and weld formation,it was found that the AC-DC mixing output could refine the weld grains,reduce the burning rate of tungsten electrode and improve the weld quality.

关 键 词：交直流混合 变极性等离子弧焊接 立焊 

分 类 号：TG456.2[金属学及工艺—焊接]