The creation and development of industrial furnace plays a very important role in human progress. In the Shang Dynasty, a copper smelting furnace with a temperature of 1200 ℃ and an inner diameter of 0.8 m appeared. In the spring and Autumn period and the Warring States period, people further mastered the technology of raising the furnace temperature on the basis of copper melting furnace, and thus produced cast iron. In 1794, the straight barrel Cupola for melting cast iron appeared in the world. Later, in 1864, French Martin built the first steel-making open hearth furnace heated by gas fuel based on the principle of Siemens regenerative furnace. He used the regenerator to preheat the air and gas at high temperature, so as to ensure the temperature above 1600 ℃ required for steelmaking. Around 1900, the power supply was gradually sufficient, and various resistance furnaces, electric arc furnaces and cored induction furnaces were used. Vacuum Brazing Process Of YT05 Hard Alloy And 40Cr Steel Temperature plays an important role in the hot working of metal. No matter what metal, in high temperature will become soft, and most of the metal in high temperature can be bent, silver, pressure, extrusion, rolling, high temperature will make the metal melt. High temperature can also eliminate the internal stress of metal. In order to remove the internal stress, the metal is heated and then cooled without new internal stress. This short-range process is called annealing. Heat Treatment Of Titanium And Titanium Alloys In 1950s, coreless induction furnace developed rapidly. Later came the electron beam furnace, which used electron beam to impact solid fuel, which could strengthen surface heating and melt high melting point materials. The earliest furnace used for forging heating is hand forging furnace. Its working space is a concave groove filled with coal. The air for combustion is supplied from the lower part of the groove, and the workpiece is buried in the coal for heating. This kind of furnace has very low thermal efficiency and poor heating quality, and can only heat small workpieces. Later, it was developed into a semi closed or fully closed chamber furnace made of firebrick. It can use coal, gas or oil as fuel, and electricity as heat source. Workpieces are heated in the furnace. Development and Principle of Plasma Sintering Furnace