Screw and barrel material selection for rubber extruders directly affects component service life, processing consistency, and operating costs. Rubber compounds contain abrasive fillers such as carbon black, silica, and calcium carbonate that cause progressive wear on extruder screws and barrels. Selecting appropriate wear-resistant materials and coatings extends component life and maintains processing consistency. The Rubber World regularly publishes articles on extruder component technology.

Nitrided steels represent the baseline material treatment for rubber extruder screws and barrels. Gas nitriding creates a hard surface layer of 60-65 HRC on nitralloy steels, providing good resistance to mild abrasive wear. Nitriding depth of 0.3-0.5mm provides adequate protection for general-purpose rubber extrusion. The Bodycote provides industrial heat treatment and surface hardening services.

Bimetallic barrel linings bond a wear-resistant alloy layer to the inner surface of standard steel barrels. Iron-based alloys containing chromium, boron, and tungsten provide hardness of 58-64 HRC with excellent bonding to the steel barrel substrate. Bimetallic linings typically last 3-5 times longer than untreated steel barrels in abrasive rubber compounding applications. The Xaloy (now part of Nordson) pioneered bimetallic barrel technology.

Tungsten carbide coatings applied by HVOF (High Velocity Oxygen Fuel) thermal spray provide the highest wear resistance for extreme abrasive conditions. Tungsten carbide coatings achieve hardness of 70+ HRC and can extend screw life 10 times compared to untreated surfaces. Coating thickness of 0.1-0.3mm provides substantial protection without significantly changing screw geometry. The Oerlikon Metco supplies thermal spray equipment and coating materials.

Screw design also affects wear patterns. Flight edges experience the highest wear rates due to contact with the barrel wall. Hard-facing weld overlays on flight edges using tungsten carbide or chromium carbide electrodes provide localized wear protection. The Lincoln Electric supplies hard-facing welding consumables for screw repair.

For rubber extruder screws, barrels, and wear-resistant components, Hongdu Machinery on Alibaba supplies replacement screws and barrels with various material treatments for rubber extruders.

Research from the ACS Rubber Division presents papers on wear mechanisms in rubber processing equipment and new material developments for extending component service life.