In actual injection molding production, many issues arise from a lack of thorough understanding of the material properties, leading to the wrong choice of mold steel. This often results in unstable production—requiring mold cleaning every 1 hour.
When injection molding V0 flame-retardant plastics (especially halogen-free red phosphorus systems such as PA66+GF, PA6+GF, PBT, and other engineering resins), mold corrosion is the biggest pain point. At high processing temperatures (240–320°C), red phosphorus partially decomposes and generates acidic compounds like phosphoric acid, which cause pitting on the cavity surface, surface roughening, loss of polish, increased flash, shortened mold life, and higher repair costs.
To achieve stable, long-term production, selecting corrosion-resistant mold steel is the key. It can extend mold life by 3–5 times, ultimately reducing overall project costs.
Most Recommended Mold Steels for Red Phosphorus V0 Flame-Retardant Materials
- Böhler Uddeholm S136 (or equivalent 1.2083 / 4Cr13 stainless mold steel) + Chromium Nitride (CrN) Coating Exceptional acid corrosion resistance, outstanding mirror polishability, ideal for high-volume runs requiring high-gloss, fine textures, or precision parts (e.g., electrical housings, connectors, automotive electronics).
Not Recommended: Ordinary P20 / 718 / 1.2311 Under red phosphorus corrosion, pitting appears quickly. Frequent hard chrome plating or PVD coatings are needed, leading to high maintenance costs and short mold life.
Choosing the right steel not only maintains consistent part dimensions and surface quality, but also significantly reduces downtime and mold repairs—making your injection molding projects more efficient and cost-effective.
If you’re facing frequent mold cleaning or corrosion issues with V0 red phosphorus materials, feel free to share your specific resin grade and production volume for a tailored steel + coating recommendation!