Choosing the right mold steel directly affects mold life, part quality and overall project cost. The steel grade should match your expected production volume, the plastic material and the part requirements. Here is a practical guide to common mold steel choices.
P20 Pre-Hardened Steel
P20 is the most common pre-hardened mold steel for general-purpose injection molds. It offers good machinability and polishability at a moderate cost. P20 is a solid choice for many consumer and industrial parts with low-to-medium production volumes.
718 Steel
718 is a pre-hardened steel with better polishability and corrosion resistance than P20. It is often used for parts that require a high-quality surface finish, such as cosmetic housings and clear or transparent components.
S136 / 420 Stainless Steel
S136 is a stainless mold steel with excellent corrosion resistance and high polishability. It is commonly used for transparent parts, lenses and medical components where surface quality and material purity are critical.
H13 Hot Work Steel
H13 is a hot work tool steel used for high-volume molds and for molding abrasive or glass-filled materials. It offers good wear resistance and thermal stability, making it suitable for demanding production runs.
NAK80 Steel
NAK80 is a pre-hardened steel with high hardness and excellent polishability. It is often used for high-gloss and transparent parts that need a mirror finish, such as optical components and premium consumer products.
How to Choose the Right Steel
The right steel depends on production volume, material aggressiveness, surface finish requirements and budget. For prototype and low-volume molds, P20 or 718 is usually sufficient. For high-volume or abrasive materials, H13 or hardened S136 may be justified. A good mold maker will recommend the steel based on your specific project.
Summary
Selecting the right mold steel balances cost, mold life and part quality. D-top Mould reviews your production volume and material requirements during DFM and recommends the most suitable steel for each project. Contact us with your drawings for a quotation within 12 hours.
