|Annealing, Hardening, Tempering - Course: Working techniques of heat treatment of steel. Trainees' handbook of lessons (Institut für Berufliche Entwicklung, 27 p.)|
|7. Surface Hardening|
When workpieces shall have a hard, wear-resistant surface, but the core must remain tough, they are only hardened on the surface. Those workpieces can resist to great shock and bending stresses.