On 2018-08-08 14:48:54
Quenching process of camshaft by high frequency hardening machine
Analysis on quenching process of camshaft by high frequency quenching machine
After induction hardening of camshaft by high frequency quenching machine, austenite grains are refined to improve surface hardness, wear resistance and fatigue resistance. In addition, camshaft has small deformation, high efficiency, energy saving, automatic and mechanized operation. After high frequency quenching, self-tempering with waste heat can eliminate the stress of quenching structure. After quenching at high frequency, the heart is made of fine flake pearlite with a hardness of 255HB. The heart has good strength and high toughness.
The inductor design of high frequency quenching machine should be made according to the requirements. The shape can be copied or rounded. The height is 4 ~ 8mm higher than the camshaft, and the clearance between the inner diameter and the axial diameter is 3 ~ 4mm to avoid obvious difference in hardness caused by different clearance. Meanwhile, the position of the inductor and the camshaft should be relatively fixed. The jet hole on the inductor ensures that there is no blockage, the water pressure meets the design requirements, and the camshaft is rotatable or stationary. In mass production, all the camshaft on each quenching position should be heated at the same time to complete, otherwise, such as piecewise quenching, it is easy to appear soft spot or soft belt, directly affect the surface wear resistance of the camshaft, has a direct impact on its service life, etc. After the induction quenching of the high frequency quenching machine, the camshaft should be immediately put into the well type tempering furnace or salt-salt tempering furnace. If induction tempering or self-tempering is used, the technological parameters of heating should be mastered well. The temperature of self-tempering is higher than the furnace tempering of 50~70℃.
The camshaft made of ductile iron is mostly quenched by high-frequency quenching machine to obtain bainite structure, and its cooling medium is saltsalbath. Due to the heating of the camshaft, the aging of saltsaltsalt is obviously accelerated by the salt chloride brought in during quenching. In order to prevent accidents, it is prohibited to use charcoal to cover the surface and reduce the loss of heat, its purpose is to avoid its mixing with salt-nitrate and explosion, at the same time, salt-nitrate temperature control to meet the requirements, such as the temperature is higher than the requirements, should be necessary cooling (using coiled tubes, cooling water recycling). The parts of the high frequency quench machine after quenching are cleaned by boiling hot water, and the salt-nitrate adhesive on the camshaft is cleaned, otherwise there will be moisture absorption and surface corrosion, which will directly affect the size and surface quality of the appearance of the product.
The induction quenching principle of high frequency quenching machine for camshaft can be known. Different frequency is the depth of hardening layer, and the higher the frequency, the smaller the depth of hardening layer instead of as a result, in the process of production, according to the specific technical requirements of parts and work conditions (i.e., the depth of hardening layer and performance) to determine the reasonable process parameters, as the camshaft of medium carbon steel production, adopt the high frequency quenching process is correct, high frequency of quenching on the surface of the camshaft main work shall be carried out step by step, first carries on the bearing diameter of axle and gear surface quenching, finally completed, eccentric CAM surface hardening treatment, which can ensure the hardness after heat treatment and organization are not affected.