The Chinese clan is the first country in the world to smelt iron and steel. Our ancestors mastered some skills of iron smelting, steelmaking, casting and forging and heat treatment three thousand years ago, more than 1700 years earlier than European countries. important contributions to human progress.

Steel has become the most basic and important material for modern industrial and agricultural production, transportation, national defense and even people's life. At present, although various new inorganic materials and organic synthetic materials have been greatly developed. But in terms of production cost and wide applicability, they are far from being able to replace steel. Therefore, the production capacity of steel is still one of the important symbols to measure the national strength of a country. The reason why iron and steel materials are so widely used is that iron ore deposits are concentrated, the storage capacity is large, mining and smelting are relatively economical, and semi-finished steel products have strong cold and hot deformation capabilities. The finished product has excellent mechanical properties (strength, plasticity and impact resistance) and processing properties (cutting, welding, cold deformation, etc.). However, compared with silicic acid materials, polymer synthetic materials and some non-ferrous metals, its biggest disadvantage is that it is easy to lose weight due to corrosion and even completely destroy it in the atmosphere or under various media conditions such as acid, alkali, and salt. .