Development of vacuum furnace
The creation and development of vacuum furnace plays a very important role in human progress. In the Shang Dynasty, a relatively perfect copper smelting furnace appeared in China. The furnace temperature reached 1200 ℃, and the inner diameter of the furnace reached 0.8m. In the spring and Autumn period and the Warring States period, people further mastered the technology of raising furnace temperature on the basis of copper melting furnace, and thus produced cast iron.
In order to heat large workpieces, the trolley type furnace suitable for heating ingots and billets and the well type furnace for heating long rods have also appeared. Since the 1920s, various mechanized and automatic furnace types have appeared, which can improve furnace productivity and working conditions. With the development of fuel resources and the progress of fuel conversion technology, the fuel of industrial furnace is gradually changed from solid fuels such as lump coal, coke and pulverized coal to gas and liquid fuels such as producer gas, city gas, natural gas, diesel oil and fuel oil, and various combustion devices suitable for the fuel used are developed.
The structure, heating process, temperature control and atmosphere of vacuum furnace will directly affect the quality of processed products. In the forging furnace, increasing the heating temperature of the metal can reduce the deformation resistance, but too high temperature will cause grain growth, oxidation or overburning, which will seriously affect the quality of the workpiece. In the process of heat treatment, if the steel is heated to a certain point above the critical temperature and then cooled suddenly, the hardness and strength of the steel can be improved; if the steel is heated to a certain point below the critical temperature and cooled slowly, the hardness of the steel can be reduced and the toughness can be improved.
The creation and development of vacuum furnace plays a very important role in human progress. In the Shang Dynasty, a relatively perfect copper smelting furnace appeared in China. The furnace temperature reached 1200 ℃, and the inner diameter of the furnace reached 0.8m. In the spring and Autumn period and the Warring States period, people further mastered the technology of raising furnace temperature on the basis of copper melting furnace, and thus produced cast iron.
In order to heat large workpieces, the trolley type furnace suitable for heating ingots and billets and the well type furnace for heating long rods have also appeared. Since the 1920s, various mechanized and automatic furnace types have appeared, which can improve furnace productivity and working conditions. With the development of fuel resources and the progress of fuel conversion technology, the fuel of industrial furnace is gradually changed from solid fuels such as lump coal, coke and pulverized coal to gas and liquid fuels such as producer gas, city gas, natural gas, diesel oil and fuel oil, and various combustion devices suitable for the fuel used are developed.
The structure, heating process, temperature control and atmosphere of vacuum furnace will directly affect the quality of processed products. In the forging furnace, increasing the heating temperature of the metal can reduce the deformation resistance, but too high temperature will cause grain growth, oxidation or overburning, which will seriously affect the quality of the workpiece. In the process of heat treatment, if the steel is heated to a certain point above the critical temperature and then cooled suddenly, the hardness and strength of the steel can be improved; if the steel is heated to a certain point below the critical temperature and cooled slowly, the hardness of the steel can be reduced and the toughness can be improved.
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