Twin-screw extrusion alloy

所属分类: Alloy bushing

The bushing is made of a pure alloy, which enhances its corrosion and wear resistance and extends its service life. Moreover, the pure alloy prevents rust stains, does not contaminate materials, and offers high reliability, making it particularly suitable for industries such as lithium batteries and engineering plastics.

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Detailed description

Technical Details of Alloy Liner Assembly for Twin‑Screw Extruder

1. Material & Structure

Base body: 42CrMo (quenched and tempered) / 40Cr. It provides structural strength, withstands high temperature and high pressure, and ensures stability of assembly interference fit. Alloy inner lining: Centrifugally cast nickel‑base tungsten carbide alloy; cobalt‑base alloy is selected for highly corrosive working conditions. Alloy layer thickness: 1.5～3.0 mm Alloy layer hardness: HRC 58～64

Process requirement: The alloy layer is metallurgically fused with the base body. Delamination, pores and cracks are prohibited, and peeling of the alloy layer is not allowed.

2. Key Geometric Parameters

Twin‑hole layout: Two parallel circular holes. Hole walls intersect to form intermeshing cavities. Inner bore diameter: Matched with screw outer diameter, commonly Φ20～Φ120 mm. Center distance: Core dimension for twin‑screw, with strictly controlled tolerance. Liner type: Segmented modular design, customized according to the length of barrel modules. Inner bore surface roughness: Ra≤0.8 μm to reduce material adhesion. Geometric tolerance: Cylindricity, coaxiality and center distance of twin bores are key inspection items.

3. Working Performance Parameters

Operating temperature: Ambient temperature ～ 350 °C Maximum material pressure: ≤50 MPa Applicable materials: Glass‑fiber reinforced materials, high‑filled materials with calcium carbonate / talc powder, PLA/PBAT biodegradable materials, PVC, conductive carbon black masterbatch, etc. Typical failure modes: Abrasive wear of inner wall, pitting corrosion of alloy layer, peeling and spalling of alloy layer, carbonization due to material accumulation.

4. Machining & Inspection Key Points

Rough machining of base body → centrifugal casting of bimetallic alloy → fine boring and honing of twin bores. Inspection items: Alloy layer thickness, hardness, metallographic analysis, penetrant testing (PT), dimensional and geometric tolerances. Assembly: Press‑fitted into barrel body by interference fit to avoid loosening under high‑temperature service.

Functions of Alloy Liner for Twin‑Screw Extruder

•Wear protection: The hard alloy layer resists cutting wear caused by glass fiber and inorganic powder, protects the barrel base body and extends service life.

•Chemical corrosion resistance: Nickel‑base / cobalt‑base alloy resists corrosion from acidic materials and chlorides generated by PVC decomposition, reducing pitting pits.

•Form intermeshing cavity: The twin‑hole profile cooperates with a pair of intermeshing screws to complete material conveying, shearing and dispersive mixing.

•Pressure‑bearing support: The alloy steel base bears high internal extrusion pressure and prevents barrel deformation.

• Thermal conduction & temperature control: The outer wall of the liner closely fits the barrel base for uniform heat transfer, stabilizes material processing temperature and reduces thermal degradation.