The material composition of the bimetallic screw has a significant impact on its performance in the extrusion process, mainly reflected in the following aspects:

1. Wear resistance and life: The use of high-hardness, wear-resistant alloy steel can effectively extend the service life of the screw. These materials can still maintain stable performance under high-speed operation and high-pressure environments.

2. Thermal stability: The screw material must have good thermal conductivity and high-temperature oxidation resistance to ensure that it will not deform or anneal when processing high-temperature plastics, thereby maintaining stable extrusion quality and output.

3. Corrosion resistance: For some highly corrosive materials, the screw surface is often specially treated (such as chrome plating or nitriding) to enhance its corrosion resistance and reduce maintenance requirements.

4. Mechanical strength: High-strength alloy steel can withstand higher torque and shear force, while improving production efficiency and reducing the risk of breakage.

5. Surface finish: High-quality materials and precision processing technology can improve the surface finish of the screw, reduce friction resistance and material residue, and improve the plasticizing effect.