H13,Hot work mold steel,4Cr5MoSiV,X40CrMoV5-1,W-Nr.1.2344

1. Pre-heat treatment H13 steel and mold blanks supplied on the market have been annealed in steel mills to ensure good metallographic structure, proper hardness, good processability and no need for annealing. However, after the forging of the manufacturer, the original structure and properties were destroyed, the forging stress was increased, and re-annealing was necessary.

The isothermal spheroidizing annealing process is: heating at 860~890 °C for 2 h, cooling to 740-760 °C for 4 h, and cooling the furnace to about 500 °C.

2. Quenching and tempering require good toughness mold quenching process specification: heating temperature 1020~1050 °C, oil cooling or air cooling, hardness 54~58HRC; mold hardening process specification requiring hot hardness, heating temperature 1050~1080°C, Oil-cooled, hardness 56~58HRC.

Recommended tempering temperature: 530 ~ 560 ° C, hardness 48 ~ 52HRC; tempering temperature 560 ~ 580 ° C; hardness 47 ~ 49HRC.

Tempering should be carried out twice. When tempered at 500 °C, the secondary hardening peak of tempering occurs, and the tempering hardness is the highest, and the peak value is about 55HRC, but the toughness is the worst. Therefore, the tempering process should be avoided at around 500 °C. According to the use of the mold, tempering is better in the range of 540~620 °C.

The quenching heating should be preheated twice (600~650 °C, 800~850 °C) to reduce the thermal stress generated during the heating process.

3. Chemical heat treatment If the gas is nitrided or nitrocarburized, the mold can be further strengthened, but the nitriding temperature should not be higher than the tempering temperature to ensure that the core strength is not reduced, thereby improving the service life of the mold.