Induction heating is an energy-saving and environmentally friendly technology

Conserving resources is our country's basic national policy. Conserving energy, improving energy efficiency, protecting and improving the environment, and promoting comprehensive, coordinated and sustainable economic and social development are my country's current strategic tasks. Premier Wen Jiabao pointed out at the 2007 National Working Conference on Energy Conservation and Emission Reduction that “eliminating outdated production capacity is an important means to achieve energy conservation and emission reduction goals”. We must vigorously eliminate outdated processes, equipment and technologies that consume high energy and pollute the environment, accelerate the development of energy-saving technologies, vigorously promote and apply new technologies, equipment, new technologies and new products that are energy-saving and environmentally friendly, and at the same time make full use of waste heat and waste. Pressure.

In my country's ferrous metal, non-ferrous metal, machinery manufacturing, automobile, military and other industries, the heating equipment in the thermal processing workshop consumes a lot of heat and has low heating efficiency. The heating before the hot forming of the blank, the heat treatment of the workpiece, and the melting of non-ferrous and ferrous metals mostly use oil furnaces, natural gas furnaces, and resistance furnaces. A few use induction heating furnaces and induction melting furnaces, and some factories use coal furnaces to heat the blanks. , Its energy consumption is high, and the pollution to the environment is serious. With the development of my country's industry, the improvement of product quality requirements, the strict requirements of energy saving, consumption reduction and environmental protection have gradually developed from flame furnace heating to electric heating.

Induction heating is an advanced technology. Compared with flame furnace and resistance furnace heating, its main advantages are:

Fast heating speed can double the productivity of heating equipment, and can be combined with other process equipment to form a continuous production line.

The heating time is short and the efficiency is high. The efficiency of induction heating furnace can reach 60% -70%, the efficiency of induction melting furnace can reach 65% -75%, while the heating efficiency of flame furnace is only about 20%, and the heating efficiency of resistance furnace Only about 40%.

When the induction heating method is used for heating before thermoforming, due to the fast heating speed and short heating time, the burnout rate of the oxide scale produced by the blank is 0.5%~1%, while the metal burnout rate of the flame furnace is 3%. Compared with the flame heating furnace, the furnace saves 2% of the material, and at the same time increases the service life of the forging die.

If an induction heating furnace is used in the thermal processing workshop, the temperature in the workshop will be greatly reduced due to less heat loss, which improves the working conditions of the workshop. In addition, because induction heating does not produce smoke and smoke, it purifies the working environment of the workshop.

However, the size of the blank that can be heated in an inductor is limited, and it is not as flexible and versatile as flame furnaces and resistance furnaces. Therefore, induction heating is suitable for the production of product parts with simple blank shapes, few varieties and large output.

Due to the above-mentioned advantages of induction heating and the gradual improvement of people’s awareness of energy saving and emission reduction, more and more energy-saving and environmentally-friendly new processes, new equipment, and new technologies have been used in actual production, and backward processes, equipment and technologies have been eliminated. technology.

In terms of electric heating, resistance furnaces are rarely used for the heating of blanks before thermoforming. Because the heating temperature of blanks is relatively high and limited by electric heating elements, induction heating is mainly used. Induction heating before hot forming. The blank has been used in the forging, hot stamping, hot extrusion and hot cutting of the blank.

In the heat treatment of the workpiece, the flame furnace is heated to the resistance furnace. For workpieces with relatively simple shapes, such as uniform cross-section steel pipes, bullets and cartridges, and container welds, induction heating has been used for normalizing, annealing, and quenching and tempering heat treatment.

In terms of preheating at lower temperatures, preheating is carried out in resistance furnaces and oil bath furnaces. Induction heating has been used for the thermal charging and thermal unloading of the inner ring of the bearing, and the thermal sleeve of the motor rotor and shaft.

In the smelting of steel and non-ferrous metals, intermediate frequency and power frequency induction melting furnaces have been used.

While using induction heating, attention should also be paid to energy saving and emission reduction. The cooling water of the inductor should be fully utilized, and the residual heat after the forging of the blank should be fully utilized as much as possible. Because the surface temperature of the blank is lowered after forming, and the temperature of the central part is higher, the advantage of induction heating speed can be used to supplement the heating of the blank, so that the surface of the blank can quickly reach the temperature required for reprocessing, so as to make full use of the waste heat of the blank itself. Its energy saving effect is obvious.

In my country’s ferrous metal, non-ferrous metal, machinery manufacturing, automobile, military and other industries, the technical transformation of old factories and the construction of new plants, the hot forming of blanks and the heat treatment of workpieces, and the selection and selection of ferrous and non-ferrous metals The heating method is used to save energy, improve the environment and increase the quality and quantity of products. The induction heating technology itself is an energy-saving and environmentally friendly technology. The key lies in how people use this technology in production to achieve the purpose of energy saving, consumption reduction and environmental improvement.