Effects of Advanced Laser Processing on the Microstructure and Residual Stresses of H13 Tool Steel

Karel Trojan¹, Václav Ocelík², Nikolaj Ganev¹, Stanislav Němeček³ and Jiří Čapek¹

¹CTU in Prague, Department of Solid State Engineering, Faculty of Nuclear Sciences and Physical Engineering, Trojanova 13, 120 00 Prague 2, Czech Republic

²Department of Applied Physics, Zernike Institute for Advanced Materials, Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands

³RAPTECH s. r. o. ,U Vodárny 473, 330 08 Zruč-Senec, Czech Republic

The aim of the contribution will be to describe the effects of laser processing on the microstructure and residual stresses of laser cladded H13 tool steel on the classical construct steel S355 substrate. The comparison of surface residual stresses obtained by X-ray diffraction in direction parallel (L) and perpendicular (T) to the clad is plotted in Fig. 1. Residual stresses at the beginning and the end of the clad are comparable with the experimental error. In the direction L, residual stresses exhibit slight compressive stresses along the clad. However, in the direction T, tensile residual stresses were obtained. Our research concludes that in this case of laser cladding, phase transformation and not shrinkage is likely to be a dominant effect on the formation of compressive residual stresses along the clad. Furthermore, martensitic structure and unequal concentration of alloying elements was observed on the cross-section of the clad using electron backscattering diffraction and energy-dispersive X-ray spectroscopy. These results will be compared with the data obtained by the X-ray diffraction.

Fig. 1: Surface residual stresses on the top of the clad in direction L and T along the length of laser track, where x is the distance from the beginning of the clad.

Measurements were supported by the project TH02010664 of the Technology Agency of the Czech Republic and by University of Groningen. This work was supported by the Student Grant Competition CTU in Prague grant No. SGS16/245/OHK4/3T/14.