Ironmaking in China began in the Spring and Autumn Period. At that time, the ironmaking method was block ironmaking, that is, at a lower smelting temperature, iron ore was reduced to sponge iron in solid state and then forged into iron blocks. Generally speaking, there are three kinds of smelting blocks for ironmaking: ground furnace, flat furnace and shaft furnace. Soon after China mastered the massive ironmaking technology, liquid pig iron containing more than 2% carbon was smelted for casting tools. As early as the Warring States Period, China had mastered the technical methods of decarbonization and heat treatment, and invented ductile iron. In the late Warring States period, a reusable "iron model" (an empty stomach made of iron for casting metal objects) was invented.
During the Western Han Dynasty, the crucible ironmaking method appeared. At the same time, the scale of ironmaking shaft furnace has been further expanded. 1975, the site of iron smelting in Han Dynasty was discovered and excavated in Guxing town near Zhengzhou, with an area of120,000 m2, and two parallel blast furnace foundations were excavated, with a blast furnace volume of about 50m3. In the Western Han Dynasty, the "steel explosion method" was also invented, that is, a new process of "frying" wrought iron or steel with pig iron, and the product was called steel explosion. At the same time, the technology of "hundred steelmaking" came into being. In the Eastern Han Dynasty (AD 25-220), when Emperor Guangwu was in power, he invented the hydraulic blast furnace, namely "drainage". The invention of ancient water rafts in China was about 1 100 years earlier than that in Europe.
After the Han Dynasty, the method of pouring steel was invented. The Book of the Northern Qi Dynasty, Biography of My Mother's Huai Wen, is called "Su Gang", later called Guan Gang, and also called Tuan Gang. This is another great achievement of China's ancient steelmaking technology.