At present, our automobiles, tractors, farm vehicles on the shaft parts, the choice of substantially 45 steel, . 4 0 C R & lt steel two steel grades. Material for the next process line - a roughing - a quenching and tempering treatment - - finishing. Over the years, quenching and tempering heat treatment process is employed; box resistance furnace by heating, the heating temperature is 820-860 deg.] C, holding at this temperature to work

When the parts are heated and the temperature is uniform, the water medium is quenched and cooled, followed by high temperature tempering. The operation mode of the box-type resistance furnace is periodic, and the heating period is 2-3 hours. In this traditional operation method, in mass production, there are problems such as unstable quality of the shaft, low efficiency, and large energy consumption. With the development of Intermediate frequency power supply , its application fields are constantly expanding. It has been used in the heat treatment and heating of equal-diameter shafts, but the uniform temperature of the stepped shaft at different diameters cannot be guaranteed, which limits its application.

Continuous intermediate frequency induction heating furnace used for quenching and tempering or normalizing heat treatment of stepped shaft parts to replace existing equipment, thereby improving the technological level of shaft quenching and tempering and normalizing heat treatment.

Based on the continuous induction heating furnace , a radiant tube is added at the discharge end of the furnace , thereby increasing a radiant heating area, which is connected to the induction heating area smoothly and correspondingly. The heating of the radiant tube is completed by the inductors arranged on the periphery thereof, and the inductors located on the periphery of the lining of the radiation zone and the inductors of the induction heating zone are connected in series

And the energy is provided by the same intermediate frequency power supply .

    The temperature of the radiant tube depends on the power consumed by the radiant heating section and the design of the radiant tube.

    Continuous medium frequency induction heating furnace, the radiant tube in the radiation area is made of ferrous metal. It is suitable for continuous heating of heat treatment with stepped shaft after rough machining. Can replace the original box-type resistance furnace. Compared with box-type resistance furnaces, the one-time pass rate of quenching and tempering quenching hardness can be increased from the original 60% to more than 90% . The straightening rate of long shaft parts is reduced by 40% . Save electricity 30% . And significantly improve work efficiency, easy to achieve automated production.

The following describes specific embodiments with reference to the drawings:

  Fig. 1 is a longitudinal sectional view of the structure of a stepped shaft intermediate frequency induction continuous heating furnace.

  Fig. 2 is a working principle diagram of a step shaft intermediate frequency induction continuous heating furnace.

In Fig. 1 , 1 is the insulation layer and refractory layer of the induction furnace; 2 is the inductor; 3 is the furnace lining; 4 is the radiation tube.

In Fig. 2 , 5 is a thyristor intermediate frequency inverter, which converts a three-phase 50- meter alternating current into a single-phase intermediate frequency alternating current. The compensation capacitor 7 and the induction furnace 8 form an intermediate frequency load. The power on the load is adjusted by the power regulator 6 as needed.

In FIG 1 , the induction heating zone 1 and the radiant heating zone 11 together constitute a stepped shaft frequency induction heating furnace continuous furnace, two smooth docking area, the induction heating zone located in the insulation, the refractory layer 1 in the induction heater 2 sequence connected to the lining 3 outside, and the irradiation zone 11 of the inductor 2 in series by an intermediate frequency power source to provide the same energy; in the irradiation zone 11 within which the lining 3 on the inner wall of the fixed radiation tube made of ferrous metal 4 , The radiant tube 1 is heated by an inductor 3 provided outside the furnace lining . When in use, the work is fed into the furnace step by step in the direction of the arrow shown in Figure 1 . Workpiece a surface temperature rises to a work area

The temperature specified by the art enters zone 11 , where the workpiece and the radiant tube exchange heat. The temperature of the workpiece is affected by the temperature of the radiant tube, and the temperature of the stepped shaft parts tends to be consistent with the radiant tube. Finally, a workpiece with uniform temperature is obtained.