Peeling

Peeling (centerless peeling) is the process of removing decarburization layer, cracks, inclusions, and oxide residues from the surface of hot rolled or forged steel bars through machining. As a result of this process, a flawless surface is achieved and bars are brought to precise tolerance classes (h7–h11).

On the centerless peeling machine, a 0.5–3 mm thick layer is removed from the surface as the bar passes between rotating cutter heads. During processing, the bar rotates on its own axis on support rollers — thus homogeneous cutting is achieved without centering. The online laser measurement system continuously controls the diameter during peeling.

For applications requiring higher surface quality (piston rod, hydraulic cylinder shaft), centerless grinding is applied. With grinding, Ra ≤ 0.4 µm and h7 tolerance values are achieved. Even Ra ≤ 0.1 µm can be obtained with super-finishing or polishing.

Each bar undergoes 100% surface scanning with an Eddy current device. Even sub-surface defects at 0.1 mm depth are detected and defective areas are marked. Peeling is a critical quality step especially in free-cutting steels, hydraulic applications, and precision shaft production. Certified delivery is made according to EN 10278 and EN 10277 standards.