两相区热处理对9Ni钢性能的优化.pdfVIP

两相区热处理工艺对 9Ni 钢低温韧性的优化1 张 坤 唐 荻 武会宾 （北京科技大学高效轧制国家工程研究中心，北京 100083 ） 摘 要 利用X 射线衍射（XRD ），夏比冲击（CVN ），扫描电镜（SEM）, 透射电镜（TEM ）, 电子背散射衍射 （EBSD ）对淬火+两相区淬火+ 回火（QLT ）和淬火+ 回火（QT ）处理的9Ni 钢中逆转变奥氏体的体积分数，形貌， 分布及其低温韧性进行了研究，结果表明，QLT 处理后，9Ni 钢中逆转变奥氏体的体积分数为8.4%，逆转变奥氏 体以块状和薄膜状形态存在，Akv(-192 ℃)平均为130J，冲击断口为韧性断裂，逆转变奥氏体不但分布在原奥氏体 晶界上，也分布在板条界上； QT 处理后，逆转变奥氏体体积分数为3.7%，逆转变奥氏体主要以块状形态存在， Akv(-192 ℃)平均为85J，冲击断口以韧性为主，也有部分脆性断裂，逆转变奥氏体主要分布在原奥氏体晶界上。 关键词 9Ni 钢 两相区淬火 逆转变奥氏体 低温韧性 Effect of QLT Treatment on Cryogenic Toughness of 9Ni Steel Zhang Kun Tang Di Wu Huibin (National engineering research center of advancing rolling, University of Science and TechnologyBeijing, Beijing, 100083) Abstract The morphology, distribution and volume fraction of reversed austenite and its cryogenic toughness of 9Ni steel treated by quenching+dual-phase quenching+tempering (QLT) and quenching+tempering (QT) were investigated in virtue of X-ray diffraction (XRD), Charpy-V notch (CVN), scan electron microscope (SEM), transmission electron microscope (TEM )as well as electron back scatter diffraction (EBSD). The results show that the volume fraction of reversed austenite in QLT-treated steel is 8.4%, the reversed austenite occurred in formation of blocky and thin film, average Akv(-192℃) is 130J, ductile fracture predominated the fracture surface and the reversed austenite distributed not only on prior austenite boundaries but also along lath boundaries. On the other hand, the volume fraction of reversed austenite in QT-treated steel is 3.7%, reversed austenite occurred in the formation of