Why S136 Stands Out
When producing plastic molds that demand exceptional corrosion resistance and a high surface finish, S136 steel stands out as the industry benchmark.
As a premium stainless mold steel, it offers an ideal balance of strength, toughness, and corrosion resistance, making it the preferred choice for precision and transparent plastic molds.
1. The Unique Features of S136 Steel
Developed by Uddeholm (Sweden), S136 is a high-chromium stainless mold steel manufactured using the Electroslag Remelting (ESR) process.
This refining method ensures exceptional cleanliness, uniform structure, and excellent performance stability.
Key advantages include:
- Outstanding corrosion resistance — With approximately 13% chromium, S136 resists rusting even in humid or acidic plastic environments.
- Excellent polishability — Capable of achieving a mirror-like surface finish, ideal for transparent parts such as lenses, medical components, and cosmetic packaging.
- High dimensional stability — Uniform hardness and minimal deformation make it suitable for high-precision mold machining and finishing.
2. Why Choose S136 for Stainless Steel Molds
S136 is the go-to material for molds requiring durability, precision, and corrosion protection.
Typical applications include:
- Transparent plastic molds (optical lenses, medical parts, cosmetic packaging)
- Corrosion-resistant molds for PVC, acetate resin, or other chlorine-containing materials
- Precision injection molds for electronics housings and optical components
Compared with traditional mold steels such as P20 or 718, S136 offers natural rust resistance without chrome plating or surface treatment.
This reduces maintenance frequency and costs while extending the overall service life of the mold — a more economical long-term solution for manufacturers.
3. Practical Benefits for Mold Manufacturers
Using S136 stainless mold steel provides several tangible advantages:
- Lower maintenance needs — Reduced downtime and polishing frequency.
- Extended mold life — Maintains high gloss and surface quality through repeated molding cycles.
- Improved product finish — Especially suitable for transparent or mirror-surface parts where clarity and detail matter.
4.Heat Treatment Advice
To achieve optimal mechanical performance, vacuum quenching followed by double tempering is recommended.
This treatment results in a hardness range of HRC 48–52, delivering the ideal balance between toughness and mirror polishability.
Proper heat treatment not only enhances mold durability but also ensures consistent performance over long production runs.
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