When did the technology of iron smelting develop

When did China produce iron-smelting technology?

Answer: Mid-spring and autumn.

The No. 1 blast furnace in the Han Dynasty iron-smelting blast furnace site in Guxing Town, Zhengzhou, Henan Province is the earliest blast furnace with advanced structure in China.

China mastered the iron-smelting technology in the middle of the Spring and Autumn Period; Cast iron (also called pig iron) can be smelted no later than the late Spring and Autumn period, nearly 2,000 years ahead of Europe. The primary reason for the rapid development of China's ironmaking technology is that blast furnace ironmaking was the first in the world.

The blast furnace of iron smelting in China was developed from the shaft furnace of copper smelting. In the Spring and Autumn Period, China has been widely used to smelt copper in shaft furnaces. The three copper-smelting shaft furnaces of the Spring and Autumn Period, which were discovered in the Daye area of Hubei Province, are very similar to the blast furnaces used for ironmaking after restoration.

According to the current archaeological discoveries, the earliest blast furnace in China was produced in the Han Dynasty. The ruins of the iron-smelting blast furnace of the Han Dynasty have been found many times in Henan, Jiangsu, Beijing and Xinjiang, among which the most advanced one is the No. 1 blast furnace in Guxing Town, Zhengzhou, Henan. After restoration, the blast furnace body is meters high and oval-shaped, and this furnace structure can overcome the difficulty of the wind blowing in the center.

The lower part of the blast furnace wall slopes outwards to create a 62-degree ventral angle, so that the charge at the edge is in fairly good contact with the gas. The whole furnace may have 4 air outlets, and 4 skin bellows are used to blow the air. The volume of this blast furnace is about 44 cubic meters, and the daily output is about 1 ton.

About 2,000 years ago, China's blast furnace already had such an advanced structure, which is really an outstanding achievement. This was unmatched by other countries in the world at that time.

According to archaeologists, the Chinese artificially made iron in the late Spring and Autumn period, and the conclusion can be drawn from the excavated iron tools.

Due to the invention of the bellows, iron smelting technology was gradually produced and developed, and the first iron tools appeared.

Most of the early iron-smelting technologies used the solid reduction method, in which iron ore and charcoal were stacked layer by layer in an iron-making furnace and ignited to produce carbon monoxide, thereby reducing the iron oxide in the iron ore to elemental iron. In the early days, iron had very poor performance due to the very low smelting temperature, and it was an alloy containing a large number of carbon and oxygen impurities, which the ancients called "evil gold".

The invention of iron-smelting technology marked the end of the slave era and the beginning of feudal society. The Shang Dynasty used meteorite iron to make iron-bladed copper Yue, which shows that at that time, there was a certain understanding and mastery of the properties of iron and the technology of forging and casting, but at that time it was not known to make artificial iron.

Iron was first produced in large quantities and used in large quantities by the Hittite Empire, and by 1200 BC iron was widely used throughout the Middle East, but it did not replace bronze as a major application at the time.

China invented the iron casting technology in the Spring and Autumn Period and the Warring States Period, and a large number of iron models in the Warring States Period were unearthed in the Shouwang Tomb in Xinglong County, Hebei Province, among which there are more complex composite models and double cavities, and the more difficult metal cores are also used, reflecting the high level of casting technology at that time. The technology of manufacturing malleable castings by soft annealing and the technology of multi-tube blast invented during the Warring States period are important achievements of metallurgical technology, about 2,000 years earlier than in Europe.