Austenite Grain Growth Behavior of X80 Pipeline Steel in Heating Process

Through changing soaking temperature and soaking time, austenite grain growth behavior of X80 pipeline steel under different heating conditions was studied. Relationships of average grain size to soaking temperature and time were obtained respectively. The results show that the prior austenite grains grow with the increase of soaking temperature and time. When soaking temperature is lower than 1 180 °C, austenite grain size and growth rate are small; when it higher than 1 200 °C, austenite grains grow rapidly and abnormal grain growth appears. For soaking at 1 180 °C, austenite grain growth rate is initially high and then decreases when soaking time exceeds 1 h.