For metal forming and plastic injection industries, molds are the core carrier for product shaping, while mold steel serves as the “backbone” of molds. When facing mold wear and short service life, many manufacturers only focus on machining processes and ignore proper steel grade matching. Foshan Jinjun Metal (Taiyuan Mold Steel) compiles professional knowledge to clarify categories, characteristics and application ranges of three mainstream mold steel families.

1. Cold-work Mold Steel: Wear-resistant Material for Room-temperature Forming

Cold-work mold steel bears heavy pressure, friction and impact at ambient temperature. It requires high wear resistance and sufficient toughness to avoid edge chipping, abrasion and collapse.

Applications: Cold extrusion, stamping, blanking, cold forming rolls, cutting dies, forming rollers for keel machines and rack machines.

Common grades: Cr12MoV, DC53, SKD11, LD, 6W6, powder high-speed steel.

Typical failures: Edge wear, chipping and cracking.

2. Hot-work Mold Steel: High-temperature Steel with Thermal Fatigue Resistance

Hot-work mold steel works under repeated heating and cooling cycles. It features excellent high-temperature strength and thermal fatigue resistance to prevent thermal cracks and softening.

Applications: Aluminum alloy die casting, hot forging and hot extrusion dies.

Common grades: H13 (2344ESR).

Typical failures: Thermal fatigue cracking, high-temperature softening and cavity collapse.

3. Plastic Mold Steel: Optimized for Polishing & Machinability

Plastic mold steel is not subjected to heavy impact. Its key advantages are good machinability, mirror polishing performance and corrosion resistance. Many grades are delivered in pre-hardened condition for direct machining.

Applications: Injection molds for home appliance housings, automotive interior parts and daily consumer goods.

Common grades: S136, 718, 2311, 2738.

Typical failures: Failed mirror finish, plastic corrosion and surface scratches.

Tip: Longer mold service life does not simply come from higher hardness. Higher hardness usually reduces toughness. Excessively high hardness selected blindly will easily cause mold cracking. Material selection should consider load, production volume and workpiece material, matched with proper heat treatment to maximize mold lifespan.

Jinjun Metal supplies mold steel and complete cold roll-forming lines. With abundant on-site service experience, we provide free material selection consultation and heat-treatment recommendations to solve your mold material challenges in one stop. Technical teams from manufacturing enterprises are welcome to contact us for discussion.