Spline shaft induction heating process

What is the heat treatment of the spline shaft? What is the purpose?
The spline shaft is made of 42CrMo steel, and the processing flow is forging blank - quenching and tempering - machining - surface induction quenching - fine grinding - flaw detection - storage. The technical requirements for heat treatment are: tempering 266~311 HB, surface hardness of quenching part ≥52 HRC; depth of hardened layer of flange is 2~4 mm, width is 12 mm±3 mm; depth of hardened layer below root of shaft of shaft shaft 2~ 3 mm; the remaining part is 4~6 mm. For the medium frequency induction hardening of the semi-axle surface of the automobile, in order to improve the torsional strength, the technical requirement is that the hardened layer must start from the circular arc surface of the flange until the top end of the spline, and a ring sensor with a magnetizer is usually used.



Compared with the hardened layer structure of the automobile half shaft, the spline shaft has its special features: First, the spline shaft shaft and the non-circular surface of the flange are transitioned, and there is a boss; the second is the spline shaft. The shape of the body is irregular and stepped. Therefore, it is difficult to meet the technical requirements by simply adding a magnetizer to a conventional toroidal inductor. Need to design a double half-turn sensor to complete the task. The special structure of the process spline shaft determines that the heating method can only be used for continuous heating. For the transition arc from bottom to top, the relative position between the inductor and the workpiece can be moved by the device, so that the relative movement between the two can be realized during the whole heating process, and the relative distance between the inductor and the heating surface is ensured. It remains essentially unchanged to improve the heating effect.