The first to discover and use iron technology in warfare in Chinese history were the soldiers of the Han Dynasty (206 BCE - 220 CE). During this time, iron weapons and tools began to replace those made of bronze and other materials. The Han Dynasty is known for its advances in metallurgy, and its ability to produce high-quality iron weapons, including swords, spears, and arrows.
The Han Dynasty was able to achieve this through the development of new iron-smelting techniques, such as the use of bellows to increase the temperature of the furnace and the addition of carbon to the iron to make it stronger. These innovations allowed the Han to produce large quantities of high-quality iron weapons and tools, which helped to strengthen their military and expand their empire.
The use of iron weapons gave the Han Dynasty a significant advantage in warfare, as iron is stronger and more durable than bronze. This allowed their soldiers to better resist enemy attacks and to inflict greater damage on their opponents. As a result, the Han Dynasty was able to maintain its military dominance for centuries and to become one of the most powerful empires in Chinese history.