1Cr18Ni9Ti 对接管接头表面缺陷分析

对接管接头采用1Cr18Ni9Ti 棒材生产,经过机械加工后与相同牌号管材焊接,焊接后酸洗发现

零件表面存在缺陷。通过对失效件缺陷形貌观察、化学成分分析、金相分析及显微硬度测试,并结合酸洗试验。

结果表明:对接管接头材料内部存在沿变形流线的贫铬区,导致该区域的耐蚀性差,在机加工的过程中贫铬区

暴露在表面或近表面,在酸洗过程中该区域被优先腐蚀,形成了蚀孔类宏观缺陷,此贫铬现象为原材料缺陷。

Analysison The Surface Defects of 1Cr18Ni9Ti Butt-Joint Pipe

The butt-joint pipe was made of bars of 1Cr18Ni9Ti, weld with the same type pipe after machining,

then acid washing defects were found in the parts of suface. Through observation and analysis of suface morphology,

composition,metallography,microhardness and acid test, we can conclude that chromium depletion areas along the deformation

line was exist that cause the corrosion preventive becoming worse. In the machining process,the chromium

depletion areas expose to the surface or near the surface,corrosion first happened in the areas with the process of acid

washing,then macroscopic defects of pitting are formed. The chromium depletion phenomenon is the defects of raw material.