What are the types of cracks in the ultrasonic hardening machine and intermediate frequency hardening machine?

① Non-quenching cracks – surface cracks and T-shaped cracks on the surface edge.

② Quenching cracks – longitudinal cracks (structural stress type).

③ Arc crack (local tensile stress type).

④ Quenching cracks on large workpieces (longitudinal and transverse).

⑤ Profile surface cracks (local tensile stress type).

⑥ Delamination, the second type of stress crack.