Potential of these treatments in terms of mechanical strength
Surface heat treatment of steels

This type of treatment makes it possible to achieve high surface mechanical properties in critical functional ranges, while retaining a core ductility that ensures safe operation of the part [14] . In this way, the performance of stressed parts can be enhanced, mainly in the vicinity of the surface: resistance to fatigue – particularly under repeated non-uniform bending and/or torsion stresses –, resistance to surface fatigue (spalling), and resistance to abrasive wear.

In fatigue, it is the external fibers of the part in the case of torsion, or the bottoms of the fillets in the case of bending, that are often the most stressed. In addition to the structural reinforcement that delays crack initiation, the martensitic surface swelling that accompanies the hardening of these fibers naturally results...