φ120mm Screw PP Extrusion Line

1. Paragraph

The screw is the core component of the extruder; its material and processing quality directly determine equipment life and plasticization performance. This production line features a φ120mm large-diameter screw made of high-quality 38CrMoAlA alloy steel. This material contains aluminum, forming an extremely hard AlN layer after nitriding while maintaining good core toughness. The screw has a 30:1 L/D ratio, precision machined and fully nitrided, achieving a surface hardness of HRC58-60 and plasticizing uniformity ≥99%. This design ensures full plasticization of PP material at high extrusion rates while greatly extending screw service life, especially suitable for long-term continuous production.

2. Technical Table

3. Bullet Points

• Premium material: 38CrMoAlA nitriding steel with high surface hardness and good core toughness.

• Large diameter: φ120mm ensures ample plasticizing capacity for high output.

• Optimal L/D ratio: 30:1 provides sufficient melting, mixing, and homogenization length.

• High hardness: HRC58-60 effectively resists abrasive particles in PP and modified materials.

• High plasticizing uniformity: ≥99% ensures consistent melt temperature and viscosity.

• Nitrided layer depth: approx. 0.4-0.6mm, not easily worn through.

• Corrosion resistance: Nitrided layer resists corrosive substances like flame retardants.

• Precision machining: Optimized flight geometry reduces localized shear overheating.

• Long life: Under pure PP processing, service life can reach 5-10 years.

• Repairable: Worn screws can be re-nitrided or coated for reduced replacement cost.

4. Q&A

Q: What is special about 38CrMoAlA material?
A: It is a premium nitriding steel containing aluminum. After nitriding, it forms an extremely hard AlN layer, providing high surface hardness while maintaining good core toughness. It also offers good fatigue and corrosion resistance, making it the preferred material for extruder screws and barrels.

Q: How long does HRC58-60 hardness last? Does the nitrided layer wear out?
A: The nitrided layer depth is typically 0.4-0.6mm. When processing pure PP or low-filled materials, wear is extremely slow, and service life can reach 5-10 years. Processing glass fiber-reinforced materials accelerates wear, but still far exceeds ordinary steels.

Q: Is this material corrosion-resistant when processing flame-retardant PP?
A: Nitrided 38CrMoAlA has good corrosion resistance and can resist attack from most flame retardant decomposition products. For highly corrosive formulations, higher-grade corrosion-resistant materials (e.g., duplex stainless steel) may be recommended; please specify during procurement.