Material selection of screws

The material selection of screws mainly depends on their use environment and required performance. Common screw materials include carbon steel, stainless steel, alloy steel and copper, etc. Each material has its own unique characteristics and applicable scenarios. ‌
Common screw materials and their characteristics
‌Carbon steel‌: Carbon steel is one of the most common screw materials, which is divided into low carbon steel, medium carbon steel and high carbon steel. Low carbon steel (such as A3 steel) has a carbon content of less than 0.25% and is suitable for general use; medium carbon steel (such as No. 35 and No. 45 steel) has a carbon content of between 0.25% and 0.45%, which is suitable for occasions requiring higher strength; high carbon steel has a carbon content of more than 0.45%, but due to its greater brittleness, it is less used‌.
‌Stainless steel‌: Stainless steel has excellent corrosion resistance and is divided into two types: austenite and martensite. Austenitic stainless steel has good heat resistance and corrosion resistance, and is suitable for high temperature and corrosive environments; martensitic stainless steel has slightly poor corrosion resistance, but higher strength, and is suitable for occasions requiring high strength‌.
‌Alloy steel‌: Alloy steel improves mechanical properties by adding alloying elements and is suitable for high-load and important connection parts, such as bridges and heavy machinery and equipment. ‌Copper‌: Copper screws are commonly found in brass and zinc-copper alloys and are suitable for electrical connections and occasions requiring good conductivity.