China people entered the Iron Age from the Eastern Han Dynasty. Before that, there was a small amount of iron, so it was difficult to know whether it was made by themselves or imported. China mastered the ironmaking method in the Han Dynasty. Since the Eastern Han Dynasty, bronzes have officially withdrawn from the stage. China's ironmaking method is completely different from other parts of the world, and a large number of pig iron products are used. The ironmaking method is: iron ore is melted at the furnace temperature of 1 100 to 1200 degrees, and the iron ore flows out to become cast iron. Cast iron is hard, but brittle, so it is difficult to use in practice. Whether it is used as a weapon or an iron, it is not easy to use.
The ancients in China heated pig iron to near melting, and then forged it repeatedly to remove carbon, phosphorus and other impurities. If the time is long enough, they will get a piece of steel and then forge it repeatedly. They will get a piece of low carbon steel, which contains few impurities. The ancients called it a hundred steelmaking. This is the best iron. Forge it again and you will get wrought iron, which the ancients called soft iron.