Simply put, it is a product composed of two metals or alloys. In bimetal products, two metals are fixed together, rather than mixed together. A mixture of two or more metals is called an alloy. Bimetal screw and barrel are used to increase the life of screw and barrel, because bimetal has better effect than single metal.

Screw barrel with bimetallic characteristics. The bimetal screw barrel is made of two metals or two metal alloys, most of which are coated with additional carbide layers and other commercial coating materials. The bimetal screw barrel is not a different type of screw barrel, such as advanced design. Screws of the same design can be used in nitriding mode and bimetal mode.

The bimetallic screw barrel is made of two alloys: first as the substrate, and second as the coating material, so they have a longer life than single metal steel. Any cermet can be coated to improve wear resistance, but it is still not a bimetallic screw. Because carbide is neither a metal nor a metal alloy.