Types Of Mold Steel | VolksMolds

Common Steel Types For Plastic Molds

June 5, 2024 Cost Considerations, Injection Molds, Mold & Product, Mold Design & Manufacturing

In the plastic molding industry, manufacturers commonly use different types of mold steel for cores/cavities and bases. They select each type based on its specific properties and performance characteristics. Here’s a breakdown:

Types Of Mold Steel For Core & Cavity

	Type	Property	Usage
1	P20	Pre-hardened, around 30-35 HRC. Good machinability and polishability.	Common for general-purpose molds, including those for moderate production volumes.
2	H13	Can be hardened up to 50-54 HRC. Excellent toughness, heat resistance, and wear resistance.	Suitable for high-pressure molding and molds that require high wear resistance.
3	420 stainless	Can be hardened up to 50-55 HRC. Good corrosion resistance and polishability	Ideal for molds used with corrosive materials or environments, such as PVC or for producing optical parts.
4	S7	Can be hardened to around 54-58 HRC. High toughness and shock resistance	For molds where high impact and toughness are critical, such as for molding heavy or abrasive materials.
5	1.2344 (H13)	Hot work tool steel, excellent toughness, heat resistance, and wear resistance. Can be hardened to around 50-54 HRC	Suitable for high-pressure and high-temperature molding applications.
6	1.2738 (P20+Ni)	Modified version of P20, better toughness and uniform hardness. Pre-hardened to around 30-36 HRC	For larger molds requiring uniform hardness, such as automotive and home appliance parts.
7	NAK80	Pre-hardened, 40 HRC. Excellent machinability, polishability, and corrosion resistance	Ideal for high-precision molds, including those for cosmetic and electronic parts.
8	S136	Can be hardened to around 50-52 HRC. Excellent corrosion resistance, high polishability, and wear resistance	Used for molds that require high corrosion resistance and a mirror finish, such as for medical and optical parts.
9	718H	Pre-hardened, 33-37 HRC. Similar to 1.2738 with added nickel for improved toughness	Commonly good for medium to large-sized molds with uniform hardness requirements.

Types Of Mold Steel For Mold Base

	Type	Property	Usage
1	P20	Pre-hardened, 30-35 HRC. Good machinability	Common for mold bases, similar to its use in cores and cavities for moderate production
2	A36	Lower carbon steel, typically not hardened. Good weldability and machinability	Often used for the construction of mold bases due to its cost-effectiveness and ease of fabrication
3	C45(1045)	Medium carbon steel, can be hardened and tempered	Used for mold bases where more strength and hardness are needed compared to lower carbon steels
4	S50C	Medium carbon steel, similar to C45. Can be hardened	Another option for mold bases, providing a balance of strength and machinability.

Factors Influencing Steel Selection

Production Volume: Higher volumes require more durable, wear-resistant steels.
Resin Material: Use specialized steel if materials are corrosive or abrasive.
Mold Design: Complex designs might benefit from steels with better machinability and polishability.
Cost Considerations: Balancing performance requirements with material cost.

Each of these steel types offers specific advantages, ensuring durability, performance, and cost-effectiveness tailored to the specific requirements of the molding process.