Precision mold accessories
To extend the service life of the mold, the optimization of the heat treatment process is very important. The main factors that affect the quality of the heat treatment are heating rate, quenching temperature, cooling rate and tempering temperature. After analysis and practice by plastic mold processing manufacturers, the following heat treatment process is suitable for general enterprises and can meet the mechanical performance requirements of 4Cr5MoSiV steel at high temperatures.
1. Preheating. The temperature is 600～630℃, and the holding time is 1.5～2h depending on the size of the mold. Then the temperature is raised to 830～850℃ and the heat preservation is 1.5～2h. This process is pre-quenching pretreatment, which can reasonably adjust the microscopic defects inside the workpiece. Prepare the necessary conditions for quenching.
2, quenching. On the basis of pretreatment, the heating temperature is raised to 1040～1080℃, and the heat preservation is 2～2.5h, and the oil is quenched out of the furnace. After the plastic mold is processed, the temperature of the workpiece is reduced to about 130℃, and the oil is taken out for air cooling.
3. Tempering. After quenching, there is a large internal stress inside the workpiece, and the workpiece must be tempered in time to eliminate the stress generated during quenching. In order to avoid cracking of the workpiece, it should be heated evenly before tempering. The specific method is to heat the workpiece to 380~400℃ for 1h, then slowly heat up to 580~600℃ for one tempering, the holding time is 2h, and then air-cooled to normal temperature after being discharged from the furnace Carry out secondary tempering, the tempering temperature is 560～580℃, the holding time is 2h, and then the furnace is air-cooled.