Welding is a processing technology and a connection method in which two workpieces of the same sex or opposite sex are bonded together by heating, pressurizing, or both. Welding has a wide range of applications, both for metals and non-metals.
Welding technology emerged with the application of metals. The ancient welding methods were mainly cast welding, brazing and forging welding. The iron blade copper yue made by the Chinese Shang Dynasty is a cast and welded part of iron and copper. During the Spring and Autumn Period and the Warring States Period, there are many pan dragons on the bronze seat of Jiangu in the tomb of Marquis Yi Zeng, which are brazed and connected in sections. After analysis, the composition used is similar to that of modern solder.
Swords manufactured during the Warring States Period have steel blades and wrought iron backs. They are generally made by heating forging and welding. According to the book "Tiangong Kaiwu" written by Song Yingxing of the Ming Dynasty: In ancient China, copper and iron were heated together in a furnace, and then forged to make knives and axes; sprinkled with yellow mud or finely sieved Chen Jiubi soil on the joints, Forging and welding large ship anchors in sections. In the Middle Ages, forge welding was used to manufacture weapons in Damascus, Syria.
The ancient welding technology has stayed at the level of casting welding, forging welding and brazing for a long time. The heat sources used are all furnace fires, with low temperature and low energy concentration. They cannot be used for welding workpieces with large cross-sections and long welds. Make decorations, simple tools and weapons.