Semi-axis induction heat treatment process

The engine power is transmitted to the wheels through the transmission and the rear axle via the half shaft, so that the wheels can withstand torsional forces and impacts. The early half-shaft was quenched and tempered. Most of the axle shafts are now induction hardened. The continuity of the shaft flange and the hardened layer of the rod, and the ratio of the depth to the diameter of the hardened layer of the rod, are the keys to improving the fatigue strength of the shaft.

There are two types of semi-axis induction hardening: scanning hardening and primary heating. Scanning quenching method is suitable for mass production of multiple varieties; one-time heating method is generally suitable for mass production on a special machine. Compare with productivity, quenching quality, energy saving effect and production cost. The one-time heating method is better than the scan hardening method, but it requires a high-power power supply and a large-flow water pump, and the special inductor structure is more complicated, so the one-time investment cost is large and it is only suitable for large-scale online production.

1. The semi-axis scanning quenching method generally uses a vertical universal quenching machine or a special quenching machine. The structure of the half-axis sensor should be able to first heat the flange surface to the quenching temperature, and then scan and quench the shaft and spline.

2. The semi-axis primary heating and quenching method is an advanced process in which the quenching area of the entire semi-axis is heated at one time. It uses two rectangular effective rings with magnet guides on it to heat the rod and spline parts. The effective ring on the flange is semi-circular, and on the shaft end side, when the semi-circle is too short, the appropriate hardening pattern cannot be obtained. At times, current collectors are often attached.

The frequency of the power supply used in the semi-axial primary heating method is usually 4-8 kHz, and the power is often more than 400kw according to the size of the semi-axial heating area. Because the primary cooling area is particularly large, a large-capacity water pump is required, a polymer aqueous solution is used, and a quenching machine with a calibration roller is used. Heating, calibration, quenching and self-tempering are completed at one time. Domestic automobile manufacturers have successfully applied this process to production, achieving several times increase in productivity, greatly improving bending fatigue strength, and energy saving effects.