表面纳米化0Cr18Ni9Ti焊接接头抗应力腐蚀性能

Surface nanocrystallization of 0Cr18Ni9Ti steel welded joints and its stress corrosing resistance

关键词:  超音速微粒轰击  表面纳米化  抗H₂S应力腐蚀

Key words:  supersonic particles bombarding  surface nanocrystallization  H₂S stress corrosion resistance

摘要:

采用超音速微粒轰击(supersonic particles bombarding)技术对0Cr18Ni9Ti不锈钢焊接接头表面进行处理,利用金相显微镜和透射电镜对材料表面的微观组织进行分析,并利用恒载荷应力腐蚀装置测量了表面处理后焊接接头抗应力腐蚀情况。结果表明,经超音速微粒轰击处理,样品表层以下60μm区域的晶粒细化至纳米量级,表层晶粒平均尺寸为10.4 nm,而且表层组织得到均一化;较低应力情况下,300 h以上应力腐蚀后试样仍未出现断裂,可见经表面纳米化处理后样品的抗H₂S应力腐蚀性能得到显著提高。

Abstract:

A nanocrystalline surface layer was obtained on surface 0Cr18Ni9Ti steel welded joint with a supersonic particles bombarding (SSPB)technology.The microstructure of the welded joint surface was analyzed by means of optical microscope and TEM. The property of the welded joint to resist stress corrosion of H2 S was studied by constant load technique as well.Experimental results showed that after the SSPB treatment, the initial coarse-grained structure in the top layer was refined to the ultra-fine nanocryatal and becomes more homogeneous.The obtained mean grain size in the surface layer within 60 μm is about 10.4 nm.At the same time, the ability of the welded joint to resist stress corrosion of H₂S is enhanced remarkably after the SSPB treatment and no cracks are found after 300 h constant load testing.