N80 ERW套管调质前后焊缝组织演变的EBSD研究

EBSD study on microstructure evolution of N80 ERW casing before and after Q&T heat treatment

本文采用SEM和EBSD等显微分析技术研究了一种N80油套管调质处理（Q＆T）前后焊缝组织的演变规律。实验结果表明,经调质处理N80套管焊缝中心区的{101}〈101〉织构明显增强,而热影响区从较弱的{101}〈101〉织构变为较强的近{111}〈101〉织构。并且,焊缝和热影响区组织中取向差角小于10°的小角度晶界和大于50°的大角度晶界数量显著增加,而介于10°-50°之间的晶界数量下降。调质处理前焊缝和热影响区中晶粒尺寸分布较为均匀,而调质处理后主要以小尺寸晶粒为主。

Microstructure evolution of weldment and matrix in quenching and tempering（QT） treated N80 ERW casing was done by scanning electron microscope（SEM） and electron backscattered diffraction（EBSD）.The results show that after QT treatment,{101}〈101〉 texture in weldment is enhanced.Weak {101}〈101〉 texture in matrix changes to be strong {111}〈101〉 texture.After QT treatment,amount of low angle grain boundaries（LAGB） with misorientation angles of 10° and high angle grain boundaries（HAGB） with misorientation angles of 50° significantly increase.Amount of grain boundaries with misorientation angles between 10° and 50°decreases.Before QT treatment,grain size distributions in weldment and matrix are relatively homogenous,while after QT treatment the small grains are preponderant.