ECrNiMo-3焊接X60钢部分熔化区组织及腐蚀行为

Microstructure and corrosion behavior in partially melted zone of X60 steel welded by ECrNiMo-3 electrode wire

采用扫描电镜(SEM)、透射电镜(TEM)观察了ECrN iMo-3焊接X60钢部分熔化区微观组织形貌,并分析了Cr、N i、Mo及Fe元素分布情况,使用高温高压法加速该区腐蚀。结果表明,部分熔化区是马氏体基体上镶嵌着大量的Laves相的两相组织,此区域仅200 nm宽。腐蚀96 h后,部分熔化区与X60钢粗晶区腐蚀深度相当,腐蚀192 h后,部分熔化区出现严重的沟槽腐蚀现象。

The microstructure and corrosion morphology in the X60 steel and nickel-base alloy electrode welded zone were observed and analyzed by SEM and TEM. The gradient of alloying elements of Fe, Ni, Cr, and Mo element across the weld interface was examined by EDS. High-pressure autoclave was used to accelerate corrosion of partially melted zone. The results show that the partially melted zone are composed of martensite and Laves phase with 200 nm width. As corrosion proceed for 96 h, the corrosion depth of partially melted zone and coarse grain heat affect zone of X60 steel is almost same,and for 192 h ,serious groove corrosion is found in the partially molten zone.