a. For flanged shafts and journals, the quenching area should preferably start from the R fillet at the root of the flange. If the root does not need to be hardened, the distance between the hardening step and the root of the fillet should not be less than 5-8mm.
b. When the shaft is quenched, a 2-8mm non-hardened area can be reserved at the end of the shaft to avoid quenching cracks at the end of the shaft.
c. Adjacent hardened areas on a shaft should be kept at a large enough distance to avoid cracks in the transition area.
Heat treatment quality inspection after quenching: the hardness of both sides of the 20mm end and the vertebral body segment is allowed to be as low as 50HRC. After heat treatment, the hardness of the workpiece should be within the range of 250±15HBW. The quality inspection of medium frequency induction heating surface quenching is basically the same as the quality inspection of high frequency induction heating surface quenching.
Preventive measures are also very important for defects that are likely to occur in surface heat treatment with medium frequency induction heating. If you pay attention to these during production and processing, you will avoid a lot of trouble.