Views: 0 Author: Aurora Publish Time: 2026-08-08 Origin: Site
Food Extruder Screw Elements: Material, Classification and Selection Guide
As the core wearable parts of twin-screw food extruders, screw elements (including conveying segments and kneading blocks) directly determine production stability, material mixing uniformity and final food product quality. Widely applied in puffed snacks, pasta, pet food and aquatic feed production, these modular components undertake key functions of material conveying, shearing, kneading and plasticizing. Reasonable material selection and element configuration are essential to extend service life and reduce production costs.
Screw elements adopt a modular design, which can be freely combined according to different raw material formulas and extrusion processes, covering three mainstream types:
Conveying Elements: Focus on stable material transportation with mild shear force, ensuring smooth feeding and material advancement, suitable for conventional material delivery sections.
Kneading Blocks: The core mixing and shearing component. Different stagger angles adjust shear intensity and material residence time to realize uniform plasticization and mixing, ideal for high-fiber and high-viscosity material formulas.
Reverse/Neutral Elements: Build appropriate back pressure, prolong material processing time, and improve mixing fineness, effectively solving uneven product texture.
Food extrusion parts must meetfood contact safety standards, with excellent wear resistance, corrosion resistance and easy-clean performance. The four mainstream materials in the industry are as follows:
38CrMoAlA (Nitriding Steel): The most cost-effective universal material. After tempering and ion nitriding treatment, it features high surface hardness, good toughness and smooth polishing performance. It is suitable for conventional puffed food, common pet food and pasta production, and is the preferred choice for standard production lines.
Bimetallic Hardfacing Alloy: Based on 38CrMoAlA substrate with plasma hardfacing wear-resistant alloy layer. It greatly improves wear resistance, effectively copes with high-fiber and high-mineral raw materials, doubles the service life compared with ordinary nitriding parts, and is widely used in high-load aquatic feed and large-volume production lines.
W6Mo5Cr4V2 (M2 High-speed Steel): High integral hardness and extreme wear resistance, capable of withstanding high-torque and high-shear working conditions. It is applicable for heavy-duty kneading blocks and special abrasive material formulas, serving high-end precision extrusion production.
316L Stainless Steel: Outstanding acid and salt corrosion resistance, optimal food hygiene performance. It is mostly used for conveying elements in acidic and salty material formulas, not recommended for high-shear and high-wear working conditions.
For low-abrasion conventional formulas, nitriding steel elements balance cost and performance perfectly. For long-term continuous production of high-fiber and high-mineral materials, bimetallic hardfacing elements are more reliable to reduce replacement frequency. For special corrosive formulas, 316L stainless steel configurations ensure food safety and equipment stability.
Adhering to food-grade production standards, our screw elements feature precise dimensions, good interchangeability, excellent wear and corrosion resistance, fully compatible with mainstream extruder models.
We support customized configuration solutions for different food processing scenarios to help customers improve production efficiency and reduce operating costs.
