Steel is a general term for iron-carbon alloys with a carbon content of between 0.02% and 2.11% by mass. The chemical composition of steel can vary greatly. Steels containing only carbon are called carbon steel (carbon steel) or ordinary steel. In actual production, steel often contains different alloying elements depending on the application, such as manganese. Nickel, vanadium, etc. Humans have a long history of application and research on steel, but until the invention of the Bayesian steelmaking method in the 19th century, steel production was a costly and inefficient job. Today, steel is one of the most used materials in the world for 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.