ČERNÝ Ivo SVÚM a.s.

Spoluautoři MIKULOVÁ Dagmar, SÍS Jiří

An effect of laser hardening with two different groups of parameters on fatigue resistance of 42CrMo4 steel was studied. Basic material was heat treated with a homogenous microstructure of tempered martensite. Additional laser surface hardening was applied on relatively small samples of 8 x 8 mm cross section. Thickness of hardened layer corresponded to 1.5 – 2 mm, if evaluated from microstructure changes and approximately 0.5 mm, if evaluated from 50% drop of microhardness values. Effect of laser hardening on fatigue strength and fatigue limit was not unambiguous and depended on the treatment parameters. Both increasing and reduction of fatigue resistance was shown. Results are discussed considering effects of microstructure and residual stresses.

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