Abstract: High carbon H13 steel was spheroidizing annealed with different isothermal time and then quenched and tempered. The effect of isothermal time on microstructure and properties of the high carbon H13 steel was studied by means of scanning electron microscope, hardness test and impact property test. The results show that with the increase of isothermal time, the hardness of the high carbon H13 steel after quenching and tempering increases first and then decreases, the impact property decreases first and then increases, but the wear resistance increases first and then decreases. When the isothermal time is 2 h, there are more strip and granular carbides at grain boundary of the high carbon H13 steel after quenching and tempering, which reduces its impact property. When the isothermal time is 3 h, there are more granular carbides with larger size inside the grains of high carbon H13 steel after quenching and tempering, which improves its wear resistance significantly, and offers good comprehensive properties.

Key words: high carbon H13 steel, spheroidizing annealing, isothermal time, impact property, wear resistance