Deformation Control And Process Study On Induction Heat-treatment For Large-scale Gear

On the basis of study on deformation regularity after heat-treatment and the basic principle of induction heat-treatment at home and abroad and in accordance with the problem of rolling-race deformation produced in the process of medium-frequency hardening the large-scale gear ring, this article has analyzed the causes in light of the design and structure of the workpiece, technological process method, stress by heat-treatment and so on. The author has considered that the main cause of the deformation is the unsymmetry of structure and the thermal stress and structural stress in process of heat-treatment. With the help of analytic calculating the relative dimensions of workpiece and deformation data, the deformation regularity in process of medium-frequency hardening such hind of workpieces as the rolling race of gear ring has been sought theoretically. In the study process of technological experiment, starting with selection of the equipment and design of the inductor, working out the technological parameters, using the dissection method of the quenched sample and regulating the technological process, the reasonable technological parameters have been determined. On the base of that, the data statistics of deformation in process of hardening the gear rings have been performed. The results of statistics have shown that the deformation of such kind of gear ring rolling race after medium-frequency heat-treatment mainly is the contraction distortion in diameter and the practical deformation regularity is the same as the theoretical one. Furthermore, the scope of diameter contraction data after medium-frequency hardening the rolling race of such kind of the gear rings and the conclusion of deformation necessity have been obtained. In the light of inspection and measurement of the equipment, preparation of the hardening medium, the simulative test of technological process and the control and check of heat-treatment process of workpiece, the article has suggested the requirements for controlling the production quality of induction hardening of this workpiece. And an adopted technological allowance in diameter has been laid down to ensure that the diameter of gear ring after medium-frequency hardening is kept in the tolerance and an allowance in the large plane of gear ring has been considered to ensure that the problem of warping deformation after medium-frequency hardening will be solved. As well as the quality control measures as selecting-matching the steel balls for assembling have been considered to ensure the clearance between the balls and rolling race will be satisfactory. Meanwhile, in the article has been mentioned a suggestion of correcting the workpiece structure in the condition of keeping its property to reduce the deformation of gear ring.