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Vertical tube furnace quenching method and quenching precautions

The quenching method of vertical tube furnace adopts pre-vacuum atmosphere protection. During operation, the furnace can be pumped to a certain degree of vacuum, and then high-purity nitrogen or ammonia decomposition atmosphere can be filled into it for protection and heating. , so as to achieve the purpose of non-oxidative heating and non-decarburization bright. Using a stirring fan, it has a higher uniformity of furnace temperature.
    The heating elements of vertical tube furnaces are made of high-quality materials, have a relatively long service life, and are equipped with exhaust ports and inert gas inlets.

    The heating element of the vertical tube furnace is located on both sides and below the furnace, and there are circulating air ducts and thermal circulating fans in the furnace. The furnace cover is automatically opened and closed, and one or two pipes can be cured at a time. It is heated by electric heating element, which is generally used for the melting of non-ferrous metals and alloys with a melting point of about 1000 °C. It is made of heat-resistant stainless steel. During the heating and cooling process, the furnace is always under the protection of high-purity nitrogen to ensure that the surface of the material is bright and free of oxidation. The specific quenching methods and principles are as follows:
一、 Quenching method:
1. Single-liquid quenching: only one coolant is used when quenching the workpiece in the tubular heating furnace.
2. Pre-cooling and quenching: When the workpiece is quenched in the tubular heating furnace, the workpiece should be properly cooled before being immersed in the coolant.
3. Double-liquid quenching: The workpiece is first immersed in water to cool, and then immersed in oil to cool slowly.
4. Grading quenching: The workpiece is first immersed in molten salt to cool, and then cooled in air.
5. Hot bath quenching: The workpiece is only immersed in high temperature nitrate or alkali to cool, and finally cooled in air.
6. Isothermal quenching: The workpiece is immersed in isothermal molten salt to cool.
二、quenching matters needing attention

1. The long column workpiece should be vertically cooled in the coolant.
2. The plate-shaped workpiece should also enter the coolant vertically for cooling.
3. The cylindrical workpiece should enter the coolant vertically for cooling.
4. For workpieces with concave surface, the concave surface should be put into the coolant for cooling.
5. When the thickness of the workpiece is uneven, the thick part should be immersed in the coolant for cooling

vertical tube furnace