Heat treatment process for induction quenching scanning of bearing without soft belt starting area

Abstract

The invention relates to a bearing induction quenching scanning heat treatment process without a soft belt starting area, which comprises four inductors, the power of the four inductors is equal, and a first induction heater and a second induction heater are provided with sprayers which can be independently started and stopped through set positions; the sensors are arranged according to the actual positions of the four sensors, the sensors are started and stopped in a matched mode, and the heating temperature, the heating time and the heating times of all the positions of the initial area tend to be the same. The hardening layer obtained through the heat treatment process is better in homogenization and small in thickness fluctuation, and the fluctuation of the quenching position is smaller than or equal to 1 mm, so that the crack generation probability is small, the part production qualification rate is increased, and the service life of a bearing is prolonged. Each sprayer can be independently started and stopped along with time, cooling is more uniform, hardness fluctuation is small, local soft points cannot be generated, therefore, weak areas on the bearing cannot be generated, and the service life of the bearing is prolonged.

Description

technical field [0001] The invention belongs to the technical field of bearing heat treatment, and in particular relates to a heat treatment process for a bearing induction quenching scanning non-soft belt starting area. Background technique [0002] Induction hardening technology is a process that only treats the surface layer, so that the core of the machined part and its metallographic structure remain unchanged, or the deformation is small. It is a very versatile heating method that allows local and surface homogeneous hardening. Heating is accomplished by exposing the conductive material to a magnetic field created by high frequency alternating current through an inductor (usually a water-cooled copper inductor). [0003] The special aspect of induction heating is to generate a heat source directly at the workpiece, that is, the magnetic field generated by the inductor generates eddy currents on the surface of the workpiece, and heats the workpiece material to be proce...

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Problems solved by technology

[0008] However, if the metal body is kept at a temperature above 727 degrees Celsius for more than 5s, its structure will change and produce paramagnetism, resulting in a reduction in the effect of induction heating, and the conduction heating will be the main method.

Moreover, due to the influence of the size of the inductor itself and the distance between adjacent inductors, etc., it is difficult to ensure that the time of induction heating for each position is exactly the same when the initial position of the bearing is heated in the prior art, which means that In the initial area, the local position is pure induction heating, the local position is induction heating + conduction heating, and the local position is only conduction heating. Different heating methods and heating times lead to different states of the metal body being heated in the initial area. It is easy to cause the formation of martensitic hardening zones with different widths at these positions

According to the experimental investigation, such as figure 2 As shown, the traditional processing method fluctuates in the thickness of the hardened layer in the initial area by 3-4mm. The uneven hardened zone of this scale will lead to uneven stress distribution and excessive local stress, which is prone to cracks, and the hardened zone is locally The position that is too deep often has a coarse grain size (below grade 6) and also seriously affects the fatigue life of the bearing

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