What should be paid attention to during the quenching operation of the shaft with a hole?

When the shaft workpiece with holes is quenched, the induced current distribution around the hole is uneven, which causes uneven heating, often overheating or excessive heating, and the edge of the hole is likely to cause cracks during quenching and cooling. The hole can be inlaid with copper or plugged with copper pins, so that the induced current is evenly distributed around the hole and can prevent cracking.