Principle and Model of Phase Transformation in Ultra-High Strength Steel for Cone Crusher

The principle of phase transformation in ultra-high strength steel for cone crusher was studied by DIL805 thermal mechanical simulate, and the critical temperature was determined. The Austenite continuous cooling transformation (CCT) diagram of the steel was confirmed by thermal expansion curve, dilatometry and metallography. The phase transformation model was established and offered a theory for deciding parameters of heat treatment process. The results proved that: when the cooling rate was under 0.5 °C/s, the structure was mainly Pearlite and Bainite. With the increase of cooling rate, the content of lower Bainite increased. When it came to 1°C/s , Martensite start to transform from Austenite. When the cooling rate is 5°C/s, Pearlite disappears, Bainite and Martensite were in the majority. Meanwhile, the mathematical equations of phase transformation have high degree to fit the experimental results, and the phase transformation model is feasible.