Classification and Application of Injection Molding Screw Materials

The injection molding screw is an indispensable component in the injection molding process, and its material directly affects the plasticization effect, product quality, and production efficiency. According to the material, injection molding screws can be classified into the following categories:

1. Carbon Steel Screws

Carbon steel screws are inexpensive and have good machinability, but they have poor wear resistance and corrosion resistance. They are mainly used for processing general plastics such as polyethylene (PE) and polypropylene (PP).

2. Alloy Steel Screws

Alloy steel screws have higher hardness and wear resistance than carbon steel, and they also have better corrosion resistance. Common types include nitrided steel screws and 38CrMoAl screws. Nitrided steel screws have a hard nitride layer on their surface formed by nitriding treatment, which improves wear resistance. 38CrMoAl screws have excellent comprehensive performance and are widely used in the processing of various engineering plastics.

3. Bimetallic Screws

Bimetallic screws combine a high-hardness wear-resistant alloy layer with a tough substrate, combining wear resistance and toughness. They are suitable for processing high-filled, high-abrasive materials such as glass fiber reinforced plastics.

4. Hardened Screws

Hardened screws improve the hardness and wear resistance of the screw surface through heat treatment or surface treatment. Common hardening methods include nitriding, carburizing, and ion nitriding.

5. Special Alloy Screws

Special alloy screws use high-performance alloy materials and have extremely high wear resistance, corrosion resistance, and high-temperature resistance. They are suitable for processing special engineering plastics and high-performance materials.

Factors Affecting the Selection of Screw Materials
Type of plastic: Different plastics have different requirements for screw materials.
Processing temperature: High-temperature processing requires high-temperature resistant screw materials.
Filler content: High filler content requires high wear resistance of the screw.
Production efficiency requirements: High production efficiency requires the screw to have good wear resistance and heat transfer.
Cost: The prices of screw materials vary greatly, and this needs to be considered comprehensively.