The growth behavior of austenite grain in the heating process of 300M steel

The 300M steel was heated in an electric furnace at the temperatures of 850, 900, 950, 1000, 1050 °C, and holding time of 5, 10, 30, 60, 90, 120 min. The grain size of austenite was measured by using the linear intercept method on Olympus PMG3 metallographic microscope. The experimental results show that grain size of austenite increases with the increasing of heating temperature and holding time, and the grain growth model of austenite in 300M steel is in the following: d = 4.04 × 106t0.17exp( − (1.32 × 105/RT)).