1.2085 Steel: Why Corroplast® is the Best Alternative

When talking about corrosion-resistant plastic molds, the market standard immediately comes to mind: 1.2085 steel. This material is the benchmark for mold bases and plates, appreciated for its resistance in humid environments and for the machinability made possible by the presence of sulfur. However, those aiming for maximum efficiency in machining operations know that crucial room for improvement exists, especially to reduce internal stresses that cause part deformation and to further accelerate drilling and milling cycles. As part of our “Specialty as Normality” column, today we analyze Corroplast®, a steel born to improve the performance of 1.2085.

The official technical brochure for Corroplast® by Deutsche Edelstahlwerke.

Click here to download the full brochure in PDF.

The direct comparison with 1.2085 steel is where Corroplast® wins the economic game. The modified chemical composition of Corroplast® (low carbon content and controlled sulfur) was specifically designed to slash machine times . The comparative data reported in the technical documentation are unequivocal:

• Drilling: Corroplast® allows working at a speed 50% higher than 1.2085.
• Roughing: 40% increase in chip removal volume per unit of time.
• Finishing and Grinding: Speed increased by 35%.

For a machine shop, replacing 1.2085 with Corroplast® means drastically reducing tool wear and freeing up valuable machine hours.

Choosing an alternative to 1.2085 doesn’t mean compromising on quality; quite the opposite. Corroplast® improves the intrinsic characteristics of standard stainless steel:

1. Corrosion Resistance: Guarantees similar or superior performance in aggressive environments.
2. Excellent Weldability: Unlike standard 1.2085 steel (which has ~0.33% carbon) , Corroplast® has a very low carbon content (0.05%). This drastically reduces the risk of welding cracks and facilitates repairs.
3. Thermal Conductivity: With values of ~24-25 W/(m K), it favors better heat exchange compared to traditional stainless steels, reducing molding cycle times.
4. Ready to Use: Supplied already pre-hardened at ~320 HB, eliminating the costs and risks of heat treatments after machining.

We don’t just rely on data sheets. Corroplast® performance compared to 1.2085 (420FM) steel has been validated by laboratory tests and industrial case histories collected in a dedicated technical paper.

Continuing to use standard 1.2085 steel out of habit means accepting avoidable machining costs. Corroplast® represents the natural evolution for those building stainless molds: same mechanical strength, but with an ease of machining that becomes the new normal. As the Italian partner of Swiss Steel Group, Bonomi Acciai is ready to support you in the transition to this high-efficiency solution.