Brazing is one of the earliest material joining methods used by mankind. Before mankind began to use ironware, brazing was invented to join metals. Among the ancient cultural relics unearthed in Egypt, there are pipes brazed with silver-copper solder and talisman boxes connected with gold solder. According to textual research, they are objects from 5000 years ago and nearly 4000 years ago. In the ruins of Pompeii buried by a volcanic eruption in AD 79, there are remnants of domestic brazed water pipes connected by brazing. The brazing filler metal used has a composition ratio of Sn:Pb=1:2, which is similar to the composition of modern brazing filler metals. .
China also used tin-lead alloy solder in the early stage of the Warring States Period in the 5th century BC, and extensively used soldering techniques in the bronze carriages of the Terracotta Warriors and Horses of the Qin Shihuang. The brazing that was first seen in the literature in China was written by Ban Gu in the Han Dynasty in "Han Shu": "Hu Tong's tears are like tears. You can weld gold and silver, and all craftsmen use it today." In 1637, the science and technology masterpiece of Ming Dynasty Song Yingxing published in Tiangong Kaiwu, it is stated that “Chinese small brazing rod uses cupronickel foam, and the big brazing rod tries to swing a hammer to strengthen it. If the silver is combined with Hutong juice, it will be as strong as a stone. Today's jade knife If you add silver to the soldering flux for handles, it will never take off. Try using a round pot mouth spot soldering flux in one corner of it. Its self-propelled, round-robin, it's also strange." This description clearly pointed out that copper brazing should use borax as the flux and silver brazing can use Hutong resin as the flux, and it gave a wonderful description of the filling behavior of the solder.
