S. Martinez, D.A. Lesyk, A. Lamikiz, E. Ukar, V.V. Dzhemelinsky

Abstract
The main problem of laser hardening process is the over-tempered structure with a hardness decrement zone in the overlapped area between different laser tracks, which may not meet the minimum hardness requirements. The over-tempered structure is located at the middle of two overlapped laser tracks or between the beginning and the ending of a closed trajectory.

In this paper, the hardness in the overlapped zones is studied by means of numerical simulations and experimental tests during a temperature controlled laser hardening with scanning optics process. Thus, in order to study their difference and to validate the proposed methodology, two steels with very different tempering curves has been used; a cold work tool steel and a medium-carbon low-alloy steel.

Keywords
Simulation; Hardness; Laser hardening; Over-tempered

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