Bench type heat treatment furnace

Bench type heat treatment furnace is a general designation of industrial furnaces which heat treat metal workpieces. The temperature is generally lower than that of the heating furnace. The bench type heat treatment furnace can adopt various types of heating furnace, but it is required to strictly control furnace temperature and furnace atmosphere. In order to control the furnace temperature accurately, some heat treatment furnaces use electric heating. The modern heat treatment process is becoming more and more complex, and there are many forms of desk type heat treatment furnace. For continuous heat treatment process, appropriate continuous heat treatment furnace shall be equipped; for periodic heat treatment process, forced circulation control atmosphere shall be adopted, and operation of furnace shall be mechanized and automated.

Commonly used desk type heat treatment furnaces include box type resistance furnace, well type resistance furnace, gas carburizing furnace and salt bath furnace, etc.

1. Box type resistance furnace: its working principle is to use the current to heat through the electric heating elements arranged in the furnace, and to heat the parts through the current and radiation. It is a widely used heating equipment in heat treatment workshop. It is suitable for annealing, normalizing, quenching, tempering and solid carburizing of steel and non steel materials (non-ferrous metals). The utility model has the advantages of simple operation, accurate temperature control, the introduction of protective gas to prevent oxidation of parts during heating, and good working conditions.

2. Well type electric resistance furnace: the working principle of well type electric resistance furnace is the same as that of box type electric resistance furnace. Its furnace mouth is upward and its shape is like a well. There are three kinds of furnace commonly used: medium temperature well furnace, low temperature well furnace and gas carburizing furnace. The shaft type resistance furnace uses crane to lift parts, which can reduce labor intensity, so it is widely used. The medium temperature well furnace is mainly used for quenching, annealing, normalizing and other heat treatment of long dry parts, and its working temperature is 950 ℃. Compared with the box furnace, the well furnace has better heat transfer, the top of the furnace can be equipped with fans, so that the temperature distribution is more uniform, and the vertical placement of slender parts can overcome the bending deformation caused by self weight when the parts are placed horizontally.

3. Salt bath furnace: salt bath furnace is a furnace type that uses molten salt as heating medium. The salt bath furnace has the advantages of simple structure, convenient manufacture, low cost, good heating quality and fast heating speed, so it is widely used. However, when heating to the salt bath furnace, there are such processes as binding and clamping of parts, complicated operation, high labor intensity, poor working conditions, and long heating up time when starting. Therefore, salt bath furnace is often used in small and medium-sized parts with high surface quality requirements.

Safe operation of bench type heat treatment furnace:

1. Bench type heat treatment furnace is an advanced heat treatment equipment which has been greatly developed in recent years. Workpieces are heated and cooled in ultra-low pressure space. It has the advantages of good quality, energy saving, safety and less pollution.

2. The heating body of the heat treatment furnace uses low-voltage power, but the power supply voltage is still 380V, so safe power is still needed during operation.

3. During the manufacturing of heat treatment furnace, it shall be ensured that there is no air leakage or water leakage. The seal of heat treatment furnace body and furnace cover is made of rubber parts, so it needs to be cooled by water interlayer. If the water leaks into the furnace, the temperature of the furnace is very high, which will cause explosion. For the workpieces processed by the heat treatment furnace, the oil stain on the surface shall be cleaned and the oil vapor from the quenching oil tank shall not enter the furnace. When the oil vapor is mixed with air, it will form an explosive atmosphere. Once there is an open fire or power on, it will produce an explosion. Therefore, the furnace door shall be closed after charging the heat treatment furnace, and the furnace can be electrified for heating only after the furnace is vacuumized.