How to optimize the heat treatment process of mold materials?
2026-01-24 16:25
Accurate control of core process parameters
Heating temperature and time: must be strictly set according to the chemical composition of the mold steel. For example, the quenching temperature of H13 mold steel is usually between 1020-1050 ℃, and the holding time needs to be accurately calculated based on the thickness of the workpiece (usually holding for 1 hour every 25mm thickness).
The choice of cooling method: This is the key to determining the final performance of the mold.
Oil cooling: With moderate speed, it is the preferred choice for most molds and can effectively control the risks of deformation and cracking.
Gas cooling (such as high-pressure nitrogen): suitable for precision molds, can achieve minimal deformation, but requires high equipment requirements.
Graded/isothermal quenching: rapidly cooling to a certain temperature and then air cooling can significantly reduce thermal stress and deformation, and achieve better strength toughness coordination.
Preventive measures for common defects
Preventing poor spheroidization and carbide segregation: By optimizing the forging process and performing correct spheroidization annealing, the carbides are improved to ensure uniform and fine distribution.
Avoid overheating, overburning, and coarse grains: strictly control the heat treatment temperature and insulation time, regularly calibrate the temperature measuring instruments, and maintain an appropriate distance between the workpiece and the heating element.
Prevention of decarbonization: Regular deoxygenation is required when heating in a salt bath furnace; When heating in a box furnace, a protective atmosphere (such as argon gas) or vacuum environment should be used, and an anti-oxidation coating should be applied to the surface of the workpiece.
Eliminating crack risk: The key lies in stress relief annealing before heat treatment and timely tempering after heat treatment. For molds with complex shapes, graded cooling or isothermal quenching should be used to reduce internal stress.
Adopting advanced surface strengthening and composite treatment technology
Surface strengthening process: A modified layer with high hardness and wear resistance is formed on the surface of the mold, which can significantly improve the life of the mold.
Nitriding/Nitrocarburizing: Improve the wear resistance, bite resistance, and corrosion resistance of the mold surface, suitable for various molds.
Laser cladding: Especially suitable for repairing worn molds or strengthening local weak areas, it can achieve the integration of strengthening and repair.
Composite strengthening and toughening treatment: For example, the double quenching method can effectively eliminate banded carbides and obtain uniform and fine carbide distribution through forging hot solution quenching and high-temperature tempering, thereby significantly improving the strength, toughness, and fatigue life of the material.
Basic principles for process selection
When choosing a heat treatment process, the principles of "working condition adaptation, substrate matching, and cost balance" should be followed. For example, for hot forging dies that withstand severe thermal impacts, priority should be given to processes that can improve thermal fatigue performance (such as composite strengthening and toughening treatment); For cold work molds that require extremely high wear resistance, surface strengthening treatment can be emphasized.
Heating temperature and time: must be strictly set according to the chemical composition of the mold steel. For example, the quenching temperature of H13 mold steel is usually between 1020-1050 ℃, and the holding time needs to be accurately calculated based on the thickness of the workpiece (usually holding for 1 hour every 25mm thickness).
The choice of cooling method: This is the key to determining the final performance of the mold.
Oil cooling: With moderate speed, it is the preferred choice for most molds and can effectively control the risks of deformation and cracking.
Gas cooling (such as high-pressure nitrogen): suitable for precision molds, can achieve minimal deformation, but requires high equipment requirements.
Graded/isothermal quenching: rapidly cooling to a certain temperature and then air cooling can significantly reduce thermal stress and deformation, and achieve better strength toughness coordination.
Preventive measures for common defects
Preventing poor spheroidization and carbide segregation: By optimizing the forging process and performing correct spheroidization annealing, the carbides are improved to ensure uniform and fine distribution.
Avoid overheating, overburning, and coarse grains: strictly control the heat treatment temperature and insulation time, regularly calibrate the temperature measuring instruments, and maintain an appropriate distance between the workpiece and the heating element.
Prevention of decarbonization: Regular deoxygenation is required when heating in a salt bath furnace; When heating in a box furnace, a protective atmosphere (such as argon gas) or vacuum environment should be used, and an anti-oxidation coating should be applied to the surface of the workpiece.
Eliminating crack risk: The key lies in stress relief annealing before heat treatment and timely tempering after heat treatment. For molds with complex shapes, graded cooling or isothermal quenching should be used to reduce internal stress.
Adopting advanced surface strengthening and composite treatment technology
Surface strengthening process: A modified layer with high hardness and wear resistance is formed on the surface of the mold, which can significantly improve the life of the mold.
Nitriding/Nitrocarburizing: Improve the wear resistance, bite resistance, and corrosion resistance of the mold surface, suitable for various molds.
Laser cladding: Especially suitable for repairing worn molds or strengthening local weak areas, it can achieve the integration of strengthening and repair.
Composite strengthening and toughening treatment: For example, the double quenching method can effectively eliminate banded carbides and obtain uniform and fine carbide distribution through forging hot solution quenching and high-temperature tempering, thereby significantly improving the strength, toughness, and fatigue life of the material.
Basic principles for process selection
When choosing a heat treatment process, the principles of "working condition adaptation, substrate matching, and cost balance" should be followed. For example, for hot forging dies that withstand severe thermal impacts, priority should be given to processes that can improve thermal fatigue performance (such as composite strengthening and toughening treatment); For cold work molds that require extremely high wear resistance, surface strengthening treatment can be emphasized.
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