Material Selection and Pretreatment

Mold steel needs to be optimized through heat treatment, commonly used materials include pre-hardened steel (such as P20, 718H) and mirror steel (such as S136, NAK80); pretreatment stage needs to be annealed or normalized to eliminate internal stresses in the material and to improve machinability.

Hardness and Wear Resistance Improvement

Quenching + low-temperature tempering process is adopted to make the surface hardness of the mold reach HRC48-55, which meets the high wear-resistant demand of injection molds; high-gloss molds are required to reduce the oxidation layer through vacuum heat treatment to ensure that the surface roughness after polishing is ≤ Ra0.02μm.

High temperature resistance and deformation resistance

Hot work die steel (such as H13) need to be tempered several times (500-600 ℃), stabilize the organization and improve thermal fatigue resistance, to adapt to the high temperature and high pressure environment of the compression mold; complex structure of the mold (such as multi-cavity mold) need to control the deformation of the heat treatment, through the grading of heating and isothermal quenching to reduce the internal stress.

Surface strengthening treatment

Nitriding treatment (e.g. gas nitriding, ion nitriding) can enhance the surface hardness to HV1000 or above, prolonging the life of blow molds and blister molds; chrome plating or PVD coating is used in high wear-resistant areas (e.g. slider, slanting top) to reduce friction and wear.

Residual stress control

Deep cooling treatment (-80~-196℃) is used for high-precision molds to eliminate residual austenite and reduce subsequent processing deformation; aging treatment (150-200℃ heat preservation) stabilizes the size and avoids product size deviation due to mold shrinkage during injection molding.

Process adaptability and efficiency

Pre-hardened steel (hardness HRC30-35) can be directly processed, eliminating the need for traditional heat treatment steps and shortening the production cycle; localized heat treatment (such as induction heating) for fragile parts (such as sprues, exhaust grooves) to strengthen and reduce costs.