Analysis of the Coating Delamination after Laser Beam Cutting

Abstract

This paper analyses surface after laser beam machining with respect of surface height irregularities, residual stress state as well as microstructure on the low alloyed steel S 235. Surface after laser beam machining is investigated due to its specific nature resulting into coating delamination. This coating delamination can be found especially in the regions in which component shape or/and curvature of the profile is altered. Especially the components corners suffer from the delamination due to exten-sive surface heating and presence of brittle oxides layer. The thickness of this oxides layer is hetero-geneous with respect of the component thickness as well as the component geometry. It was found the oxides layer is the thermally initiated process since in these regions the underlying matrix also exhibits the higher thickness of the heat affected zone and higher degree of the hardening expressed in term of HV0.1. Furthermore, also the compressive residual stresses exhibit higher amplitudes in the region remarkably affected by the thermal cycle.