X80管线钢的奥氏体再结晶行为

Austenitic recrystallization behavior of X80 pipeline steel

采用热模拟试验的方法研究了单道次变形变形量、双道次变形变形量和待温时间等不同工艺参数对X80管线钢奥氏体再结晶及晶粒长大的影响。结果表明,随着单道次变形量的增加,试验钢的奥氏体晶粒尺寸逐渐减小,当变形量为25%~30%时,奥氏体平均晶粒尺寸约为22μm。对于Nb含量约0.08%的X80管线钢来说,于980℃变形后保持1 min,奥氏体仍可发生充分的再结晶。随着待温时间的增加,奥氏体晶粒没有明显长大的趋势,晶粒尺寸为22~28μm。通过再结晶温度模型测算,试验钢的再结晶温度约为946℃,按照板坯的温降方程测算,单道次变形后的待温时间不宜超过200 s。

Effects of deformation amount of single pass deformation and double pass deformation and temperature waiting time on austenite recrystallization and grain growth of X80 pipeline steel were studied by thermal simulation experiments.The results show that the austenite grain size decreases with the increase of single pass deformation amount.When the deformation amount is 25%-30%,the average grain size of austenite of the tested steel is about 22μm.For the X80 pipeline steel with Nb content of about 0.08%,the austenite can still be fully recrystallized after the deformation at 980℃and then holding for 1 min.The growth trend of austenite grain is not obvious with the increase of temperature waiting time,with the grain size is 22-28μm.According to the calculation of the recrystallization temperature model,the recrystallization temperature of the tested steel is about 946℃.According to the calculation of the temperature drop equation of the slab,the temperature waiting time after single pass deformation should not exceed 200 s.