Rapid medium frequency heating quenching for micro deformation of large gear shafts

Large gear shaft parts are key parts on the 2450mm medium plate hot rolling mill and are made of 34CrNi3Mo steel with good hardenability. The upper gear shaft weighs 20.272t, and the lower gear shaft weighs 22.81t. The diameter of the finished product is 1160mm, the center distance is 1100mm, the module is 30mm, and the number of teeth is 32. The heat treatment and quenching hardness of the gear after tooth milling is 302-341HBW. This kind of large forged gear shaft requires high comprehensive mechanical properties. The heat treatment and processing are first quenched and tempered to ensure the mechanical properties of the core of the workpiece. Then the teeth are rough milled, and then the intermediate frequency heating and quenching treatment is accelerated. After the treatment, the comprehensive mechanical properties of the workpiece are good and the workpiece is deformed. Small, meeting the design technical requirements and obtaining good results.

Production practice shows that the gear shaft adopts rapid heating and quenching technology and related measures. The deformation of the workpiece tooth surface and the entire length of the shaft is smaller than the overall heating and grooving modulation. Therefore, the machining allowance of the tooth surface can be reduced by 1/3-1/2.

The gear shaft adopts accelerated heating and quenching treatment, the tooth surface hardness can reach 340HBW, and the comprehensive mechanical properties are good. By further improving the process, the quenching and tempering treatment can be eliminated under the condition that the gear shaft meets the technical requirements, so as to shorten the production cycle and reduce product costs. At the same time, when the workpiece is heated at an accelerated rate, the heat preservation time in the high-temperature section is extended and the heat penetration depth of the workpiece is increased, which helps to improve the overall strength of the gear shaft, improve the product performance of the gear shaft and the life of the workpiece.

The gear shaft is processed and then installed in the machine for production use. The workpiece runs smoothly, has low noise, good wear resistance, excellent comprehensive technical performance, and satisfactory production and operation results.