Thermal treatment method of spline shaft head of transmission shaft

Abstract

The invention discloses a thermal treatment method of a spline shaft head of a transmission shaft. The method is characterized by sequentially comprising a normalizing process and a medium-frequency induction quenching process, wherein the normalizing process sequentially comprises two steps of: (I) heating the spline shaft head by a push disc-type heating furnace, wherein the heating temperature is 850+/-10 DEG C, and the heating time is 120 minutes; and (II) performing air cooling for 2-3 hours; the medium-frequency induction quenching process comprises two steps of: (I) quenching, wherein the surface quenching area of the spline shaft head comprises a spline part and a full-oil seal table part, and the depth of the hardening layer is 4-6mm; and (II) low-temperature tempering. Compared with the same kind of hardening and tempering and medium-frequency induction quenching technology (needing tempering at a high temperature of 680+/-10 DEG C for 150 minutes), the method disclosed by the invention greatly saves resources on the premise of guaranteeing the static torsional strength and fatigue life of the spline shaft head, reduces the production cost, has positive social significance of low carbon and environmental protection, and remarkably improves the product competitiveness.

Description

technical field [0001] The invention relates to the technical field of metal processing, in particular to a heat treatment method for a transmission shaft spline head. Background technique [0002] The spline shaft head is one of the most important parts of the car drive shaft. The torque of the engine reaches the rear axle through the drive shaft, and is transmitted to the wheels by the half shaft to push the car forward. The spline shaft head plays a vital role in the power transmission of the automobile drive shaft. Such as figure 1 As shown, the spline shaft head includes an oil seal platform 1, a spline part 2 and a connecting screw head 3. [0003] The material of the existing spline shaft head is 40Cr steel. After forging, its heat treatment process has been using the method of quenching and tempering plus intermediate frequency induction hardening to improve the comprehensive mechanical properties of the spline shaft head such as bending and torsional strength, so ...

AI Technical Summary

Problems solved by technology

[0008] The above-mentioned existing heat treatment process is high energy consumption and high cost in the production process of parts, mainly because the tempering temperature is high and the duration is long (150 minutes) during quenching and tempering

In addition, when quenching in the quenching liquid, it also needs to consume the quenching liquid, which increases the cost of heat treatment

[0009] Compared with the quenching and tempering process, the normalizing process reduces the high-temperature tempering steps, which can save a lot of energy, but the hardness of the workpiece after normalizing treatment is lower than that of the quenched and tempered workpiece, and the strength is poor, and the fatigue life of the workpiece is short. Meeting the needs of the automotive industry

Therefore, the normalizing process cannot be applied to the heat treatment process of the drive shaft spline shaft head for a long time.

Due to the inability to overcome the above-mentioned shortcomings brought about by the normalizing process (lower hardness, poor strength, short fatigue life, etc.), it is not yet possible to use the normalizing process in this field to realize energy-saving and lower production cost drive shaft spline shafts. Head heat treatment method

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