Medium-frequency induction quenching process in heavy-duty rack with super modulus

Abstract

The invention relates to heat treatment for a rack with super modulus and particularly relates to a medium-frequency induction quenching process for a heavy-duty rack with the super modulus. An inductor is a profiling inductor in the shape which is in adaptation with the shape of the section of a tooth space of the rack, and the medium-frequency induction quenching process comprises the following steps: A) placing the rack on a medium-frequency induction quenching machine tool; B) simultaneously heating a tooth face and a tooth root of the tooth space of the rack through the inductor; C) performing air-cooling, wherein the cooling rate is greater than the critical cooling rate, and the surface temperature of a heating zone of the rack after air-cooling is positioned in a martensite transformation zone; and D) implementing liquid-cooling after temperature gradient in a depth range of a hardened layer of a surface layer of the heating zone of the rack is stable to complete structural transformation, wherein the cooling rate of liquid-cooling is greater than the critical cooling rate. According to the process, the higher hardness and the deeper hardened layer of the rack can be ensured, the stress state at the tooth root can be effectively improved, the cracking and the delayed cracking of the tooth root can be avoided, and the process is suitable for quenching the rack with the super modulus, particularly the cast rack with the super modulus.

Description

technical field [0001] The invention relates to the heat treatment of super-large modulus racks, in particular to an intermediate-frequency induction hardening process for super-large modulus heavy-duty racks. Background technique [0002] Gear and rack mechanisms are important transmission components and are also commonly used long-distance drive methods. Compared with other mechanical transmission forms such as belts, chains, friction, hydraulic pressure, and screw rods, they have high transmission accuracy and efficiency, stable transmission, and high load-carrying capacity. Strong, large power range, good reliability, unlimited length docking, compact structure, low cost, long service life, etc., are widely used in machinery, aviation, instrumentation and other industries, and become an indispensable transmission part of various machinery , occupies an important position in the modern machinery manufacturing industry. Among them, the rack is an important basic component...

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Problems solved by technology

[0007] However, the applicant found that although the quenching process in the above paper can meet the requirements of large modulus heavy-duty racks for hardness, depth of hardened layer, and continuous distribution of hardened layer along the tooth surface and tooth root, it uses spray coolant The rapid cooling method cannot eliminate the adverse effects of potential unfavorable residual stress at the tooth root of the rack on the product, and is prone to quenching cracks and deformation. machine use

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