Abstract: The Rockwell hardness and microstructure of different locations of 30CrMnSi steel bucket teeth forged and intercritical quenched were analyzed, respectively. The microstructure and properties of 30CrMnSi steel treated by different simulated forging residual heat quenching process were compared. The results show that the surface hardness of the bucket tooth is slightly lower than the subsurface by 2-3 HRC, tooth tip hardness is higher than the root by 5-10 HRC. By simulating forging residual heat subsection quenching, the impact toughness of 30CrMnSi steel is the highest when quenched at 870 ℃, which is 74 J. When the quenching temperature is below 870 ℃, the impact toughness will decrease due to inhomogeneous austenitization or the appearance of more ferrite; When the quenching temperature is higher than 870 ℃, due to the austenite grain coarsening during heating, the martensite obtained after quenching is also coarse, and the impact toughness decreases. It is suggested that the integral quenching process of the tooth tip and tooth root entering water at the same time should be adopted, in order to obtain higher hardness and toughness for the whole bucket tooth.

Key words: forging bucket tooth, 30CrMnSi steel, forging residual heat quenching, hardness, impact toughness