In twin screw extruder operations, screw elements are responsible for conveying, mixing, cutting, and dispersing materials. However, they also face highly corrosive processing conditions. Especially when processing plastics with chlorine, flame retardants, or highly acidic/alkaline additives, selecting the right corrosion-resistant materials becomes critical.
So, what corrosion-resistant materials are available for twin screw extruder screw elements?
Key Corrosion-Resistant Materials
| Material |
Features |
Applications |
| W6Mo5Cr4V2 (High-Speed Tool Steel) |
High hardness, excellent wear resistance, moderate corrosion resistance |
High-fill, high-shear extrusion with mild corrosion |
| 38CrMoAl (Nitrided Steel) |
Surface hardened by nitriding, good toughness and corrosion resistance |
General plastics, mildly acidic or neutral processing |
| PM-HIP Alloys (WR5, WR13, WR14) |
Excellent wear + corrosion resistance, uniform microstructure |
High-stress corrosive + abrasive environments |
| 440C Stainless Steel / SKD11 |
High hardness with good corrosion resistance |
Applications needing both wear & corrosion protection |
Selection Recommendations
- Corrosion-focused environments → 38CrMoAl nitrided steel, 440C stainless steel, or PM WR series
- Wear + corrosion combination → WR13, WR14, or high-hardness tool steel W6Mo5Cr4V2
- Specialized conditions → Customized PM-HIP alloys or surface treatments (e.g., coatings, laser cladding)
Summary
Choosing the right corrosion-resistant material for screw elements is key to maintaining efficient and stable twin screw extruder operation. Each material offers different balances of:
- Wear resistance
- Corrosion resistance
- Hardness
- Machinability
Proper material selection can extend service life, reduce maintenance costs, and improve production efficiency.
About ZHITIAN
ZHITIAN specializes in the R&D and manufacturing of twin screw extruder components, including screw elements, barrels, and gearboxes. With 20+ years of expertise and strong material R&D capabilities, ZHITIAN can recommend the optimal material combination for your specific processing conditions.
FAQ – Corrosion-Resistant Screw Element Materials
Q1: How to select corrosion-resistant screw element materials?
A1: It depends on processing conditions. For mild corrosion, 38CrMoAl nitrided steel or 440C stainless steel is sufficient. For combined high wear and corrosion, PM-HIP WR13 or WR14 is recommended. For extreme conditions, laser cladding or special coatings can enhance performance.
Q2: Which materials are best for high-fill modified engineering plastics?
A2: W6Mo5Cr4V2 and PM-HIP alloys WR5, WR13, WR14 are excellent for high-shear, high-wear engineering plastics while maintaining corrosion resistance.
Q3: What is the difference between PM materials and nitrided steel?
A3: Nitrided steel only has a hardened surface, while the core is softer. PM-HIP materials have uniform hardness and microstructure, offering superior durability in abrasive + corrosive environments.
Q4: Can screw element materials be customized?
A4: Yes. ZHITIAN provides customized screw elements with tailored materials, geometries, and surface treatments for specific extrusion processes.
Q5: How does corrosion-resistant material affect service life?
A5: Proper material selection can double or triple service life, reduce downtime, and ensure consistent extrusion performance.
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