摘要
本文利用光镜和透射电镜技术,对Cr-Mo-V低合金耐热钢焊接接头在770℃不同时间进行高温回火处理后,焊缝中粒状贝氏体的转变机制进行了研究。发现随回火时间的延长,富碳M-A小岛就地分解,析出细小的M_(23)C_6或M_7C_3型碳化物,并不断聚集长大;小岛边界逐渐变得模糊;基体中析出的VC颗粒大小变化不明显;铁素体晶粒长大,焊缝区的强度降低。
Transformation mechanism of granular bainite in Cr-Mo-V steel welds,with the characteristics of low alloy and heat resistant, is studied by means of optical microscope and transmission electron micro scope. When the time increases from 30 minutes to 120 minutes at high temperature 770℃ ,it is ob served that M-A original microstructures resolve,and M_(23)C_6 or M_7C_3 tiny carbides precipitate and grow from 10 nm to 65 nm,and the boundary. of M-A island becomes vague,and the size of VC precipitated from ferrite matrix is not obviously changed,and ferrite grains grow and the strength of welds is reduced.
关键词
焊缝
回火
粒状贝氏体
透射电镜
welds
tempering
bainite
transmission electron microscope
