Why does the workpiece keep rotating when the induction hardening equipment heats the workpiece?

Why does the workpiece keep rotating when the induction hardening equipment heats the workpiece? The uneven gap between the workpiece and the inductor is the main reason for the difference in the thickness of the hardened layer of the workpiece. Because the shape of the inductor cannot be made very regular, and the placement of the workpiece in the inductor cannot be right at the center, the unevenness of the gap is always unavoidable. When the cylindrical workpiece is quenched and heated, the problem of uneven heating can be solved by rotating movement. Generally, the rotation speed of the workpiece is not rigidly stipulated in the process. In actual operation, the appropriate rotation speed should be determined by trial quenching.