P20 / 718H
Balanced choices for general plastic molds and medium-volume projects. Suitable when cost control, machinability and stable mold use matter.
General housings • medium volume • balanced costResources / Mold Steel
Mold Steel Selection: Mold Life, Resin Risk and Cost Balance
The best mold steel is not always the most expensive one. It should match production volume, resin behavior, polish requirement, corrosion risk, glass fiber wear and expected mold life.
Common Steel Directions
Steel should match resin, volume, surface and maintenance expectations
Trade names and regional equivalents should be confirmed in the quotation and steel certificate requirements.
NAK80 / S136
Useful for high-polish, transparent, medical, food-related or cosmetic surface requirements. S136 is often considered when corrosion resistance is important.
Mirror polish • corrosion resistance • cosmetic partsH13 / SKD61
Stronger direction for abrasive or demanding molding conditions, such as glass-filled materials or high wear risk. Heat treatment and hardness target should be specified.
Glass fiber • high wear • heat treatmentS50C / Support Steel
Used for mold bases and non-working support parts where strength and cost balance are more important than cavity surface performance.
Mold base • support plate • cost controlSelection Logic
The Four Questions We Ask Before Recommending Mold Steel
01
Production Volume
Trial, low-volume and mass-production molds need different life expectations and cost structures.
02
Plastic Resin
PVC, POM, glass-filled PA and high-temperature materials create different corrosion and wear risks.
03
Surface Requirement
Transparent and high-gloss parts need stronger polishing and surface stability.
04
Heat Treatment
Hardness, toughness and dimensional stability depend on both material choice and heat-treatment quality.
Common Questions
Mold steel FAQ
Is the most expensive steel always the best choice?
No. Over-specification increases tooling cost and machining difficulty without necessarily improving the business case.
Why does glass fiber affect steel selection?
Glass-filled resins are abrasive and may increase wear at gates, runners and cavity surfaces.
Why is heat treatment important?
Hardness, toughness, distortion and final tool performance depend on both the steel and the heat-treatment process.
Should steel certificates be requested?
For controlled or export tooling programs, material certificates and hardness records may be included in the agreed documentation package.