Study on Microstructure and Properties of H13 Hot Working Die Steel during Tempering

H13 is a widely used hot working die steel. Good heat treatment process can improve its impact toughness and prolong the service life of the die. The microstructure and properties characteristic of H13 hot working die steel during quenching and tempering were studied. The results show that the microstructure of annealed H13 was better than that of rolled one. The dispersion distribution of carbides and its full dissolution during quenching significantly improved the impact toughness after tempering. The increase of tempering times and tempering temperature can significantly improve the properties of the material. After tempering for four times at 873K, the impact absorbed energy of annealed H13 was 19.8J and the hardness remained above 45HRC; the steel was tempered twice at 873K and at 833K respectively, the impact absorbed energy was 18.2J and the hardness was nearly 48 HRC. The coordination of tempering temperature and times can make the H13 hot working die obtain excellent properties.