X80管线钢焊接接头表面自身纳米化

Surface Nanocrystallization of Pipeline Steel X80 Welded Joints

采用表面机械研磨(SMAT)技术对X80管线钢的焊接接头进行了表面自身纳米化处理,利用金相显微镜(OM)、透射电子显微镜(TEM)和X射线衍射技术(XRD)研究了表面自身纳米化处理后试样表面微观结构的变化。结果表明:经SMAT处理后,可以在X80管线钢的焊接接头表面形成一定厚度的等轴、取向随机的纳米晶粒;随距处理表面深度的增加,晶粒尺寸逐渐增大;SMAT处理时间的进一步延长对表层晶粒尺寸影响不大;SMAT处理可以实现X80管线钢的焊接接头组织的连续化和均匀化。

Pipeline steel X80 weld joints were subjected to surface mechanical attrition treatment （SMAT）, and the microstructure change was examined by using OM, TEM and XRD. The results show that equiaxed nanocrystallites with random crystallographic orientations were obtained in the surface layer of the steel sample after SMAT for a short period time, and the grain size increases with the increasing depth from the treated top surface. Moreover, the grain refinement degree and the thickness of deformed layer can not increase obviously with the further elongation of the SMAT duration. Homogenization and continuum of microstructure of pipeline steel X80 welded joints can be achieved after SMAT.