K60、X70管线钢奥氏体晶粒长大及再结晶的对比分析

COMPARISON AND ANALYSIS ON AUSTENITE GRAIN GROWTH AND RECRYSTALLIZATION OF K60AND X70 PIPELINE STEEL

通过金相观察的方法,研究了K60、X70管线钢在不同加热温度下奥氏体晶粒长大的规律及在不同变形量和变形温度下奥氏体晶粒再结晶的规律。结果表明:加热温度分别达到1 150℃和1 200℃时,K60、X70晶粒尺寸急剧增大;随着变形温度的提高,K60、X70奥氏体再结晶的临界变形量均降低;变形温度在1 150℃,变形量分别为50%和30%时,K60、X70再结晶程度可达90%以上。相比K60,X70未再结晶区狭小,为避免混晶的产生,轧制过程应尽量避开部分再结晶区。

The behavior of austenite grain growth and recrystallization of K60 ＆ X70 pipeline steel has been studied by metallographic observation method under different heating temperatures, deformation amounts and deformation temperatures. Results showed that the grain size of K60 ＆ X70 increased rapidly when the heating temperature reached 1 150 ℃ and 1 200 ℃, and the critical deformation amount of austenite recrystallization decreased with the increase of deformation temperature. When the deformation temperature was 1 150 ℃ and deformation amount of K60 ＆ X70 reached 50% or 30%, the recrystallization degree of K60 ＆ X70 was more than 90%. Compared to K60 steel, the non-recrystallization zone of X70 steel was narrow, so the partial recrystallization area should be avoided in rolling to prevent mischcrystal from forming.