低锡Zr-4包壳管电子束焊接时发生的合金元素蒸发现象

Alloy Element Evaporation Phenomenon of Low Sn Zr 4 Cladding Tube During Electric Beam Welding

采用电子探针的波谱分析方法，对国产低锡Ｚｒ４包壳管的环焊缝试样进行表面成份分析。分析结果表明，从焊缝的外边缘到内边缘，Ｓｎ、Ｃｒ、Ｆｅ元素的化学成份在统计上呈增大趋势，腐蚀后出现了白色产物的试样表层，其Ｓｎ、Ｃｒ、Ｆｅ元素含量相当程度地降低。这一事实表明，国产低锡Ｚｒ４包壳管采用电子束焊接时，在一定的焊接规范下环焊缝的合金元素存在严重蒸发现象，特别是合金中锡元素的蒸发使其锡元素含量低于０．５％，导致了腐蚀性能的下降。

This paper analyses surface constitution for the weld samples of low Sn Zr 4 cladding tube by wave spectrum analytical method.The results show that the chemical constitutions of Sn,Cr and Fe element trends towards statistical increment from peripheral weld to medial weld,and that the constitution of Sn,Cr and Fe elements on surface of the samples being gray corrosion products are sharply lowered.It is obvious that there is a gross evaporation phenomenon for alloy element of the girth welding under certain welding specification while welding of low Sn Zr 4 cladding tube by electric beam welding,particularly,corrosion resistance of the ally will be decreased when Sn element evaporation is lower than 0.5% weigh.