Induction hardening is widely used because of its simple process, small deformation, local quenching, high production efficiency, energy saving, environmental protection, and easy mechanization and automation. Gears (including external gears and internal gears) are commonly used as mechanical transmission parts, especially large-diameter gears always use induction hardening for appearance enhancement.
1. Common methods of gear induction hardening
There are four types of gear induction hardening: gap-by-gap, tooth-by-tooth, spin hardening, and dual-frequency induction hardening. Gap-by-gap and tooth-by-tooth induction hardening are especially suitable for external gears and internal gears with large diameters (up to 2.5m or more) and large modules, but not suitable for small diameter and small module gears (modules less than 6) .
2. Key points of gap-by-gap induction hardening process control
(a) The common frequency of gear gap-by-gap induction hardening 1～30kHz, and the gap between the inductor and the parts is controlled at 0.5～1mm.
(b) The eddy current generated by the sensor along the tooth groove is butterfly-shaped, and the root current density is the highest. Therefore, it is necessary for the inductor to be equipped with a conductive magnet to use its notch drive effect to increase the current density on the surface of the tooth root near the inductor to improve the efficiency of the inductor.
(c) It is necessary to accurately control the sensor to be very symmetrical with the adjacent two tooth sides, and strictly control the clearance of the tooth side and tooth root.
(d) Reasonably match the height of the inductor and the amount of magnetizer to ensure that the heating temperature of the tooth surface and the tooth root are uniform and common to avoid quenching cracks.