A bimetallic screw is made up of two metals or alloys. As the name suggests, in a bimetallic screw, two metals are fixed together. A bimetallic screw is used to increase the life of the entire screw and barrel. That is because a bimetallic screw works better than a mono-metallic screw. Bimetallic screws are made in two metals - the base material and the coating material. That is why a bimetallic screw lasts longer than a mono-metallic screw. There are multiple applications of a bimetallic screw. It can be used for corrosion formula, regrinding resin, calcium powder filling, additive fireproof materials, and additive plastic materials with less than 15% glass fiber. STELLITE PTA welding machines are adopted for hard-facing, with the alloy thickness over 1.5 mm, providing high surfacing bonding strength, dense textile effectively improving the resistance of the screws to abrasion, high temperature corrosion. It helps extend the service life of the bimetallic screw.

The material that is used in a Bimetallic Screw is EN41B with a coating of ni-based alloy. The available diameter sizes vary from 14mm to 200mm and the available length is up to 6 meters. The surface hardness achieved through the Gas Nitriding + PTA process is 58-62 HRC.