Steel is a general term for iron-carbon alloys with a carbon content of 0.02% to 2.11% by mass. The chemical composition of steel can vary greatly. Steel containing a small amount of manganese, phosphorus, silicon, sulfur and other elements and a carbon content of less than 1.7% is called carbon steel; in actual production, steel often contains different alloying elements according to different uses, such as manganese, nickel, vanadium, etc. Humans have a long history of application and research on steel, but until the invention of the Bain steelmaking process in the 19th century, steel production was a high-cost and low-efficiency task.Today, steel has become one of the most used materials in the world with its low price and reliable performance. It is an indispensable component in the construction industry, manufacturing industry and people's daily life. It can be said that steel is the material basis of modern society.
Countersunk self-drilling screw is a special self-drilling screw with a countersunk head design, which can keep the surface flat and beautiful when tightening and avoid bulges. Countersunk self-drilling screws are widely used in various occasions that require tightening, especially in occasions that need to hide the bolt head or reduce surface bulges. The installation method of countersunk self-drilling screws is relatively simple, and no pre-drilling or tapping is required, which greatly improves work efficiency. Its unique thread design can form a good locking effect in a variety of materials (such as metal, wood, plastic, etc.).