© Copyright by International OCSCO World Press. All rights reserved. 2007 VOLUME 20 ISSUES 1-2 January-February 2007 Short paper 343 of Achievements in Materials and Manufacturing Engineering of Achievements in Materials and Manufacturing Engineering Modelling of gradient layer properties of the 32CrMoV12-27 surface layer alloyed with WC powder L.A. Dobrzański a, *, K. Labisz a , A. Klimpel b , J. Lelątko c a Division of Materials Processing Technology, Management and Computer Techniques in Materials Science, Institute of Engineering Materials and Biomaterials, Silesian University of Technology, ul. Konarskiego 18a, 44-100 Gliwice, Poland b Welding Department, Silesian University of Technology, ul. Konarskiego 18a, 44-100 Gliwice, Poland c Institute of Materials Science, University of Silesia, ul. Bankowa Str 12, 40-007 Katowice, Poland * Corresponding author: E-mail address: leszek.dobrzanski@posl.pl Received 19.10.2006; accepted in revised form 15.11.2006 Analysis and modelling AbstrAct Purpose: The reason of this work was to determine the thermal fatique resistance, the laser treatment parameters, particularly the laser power, to achieve a high value of layer hardness for protection of this hot work tool steel from losing their work stability and to make the tool surface more resistant for work. The purpose of this work was also to determine technological and technical conditions for remelting the surface layer with HPDL. Design/methodology/approach: In this paper the results of new laser treatment techniques applied in metal surface technology are presented and discussed. There is presented laser treatment with remelting of hot work tool steel 32CrMoV12-28 with ceramic powders especially carbide - WC, as well as results of laser remelting influence on structure and properties of the surface of the hot work steel, carried out using the high power diode laser (HPDL). Special attention was devoted to monitoring of the layer morphology of the investigated material and on the particle occurred. Optical and scanning electron microscopy was used to characterize the microstructure and intermetallic phases occurred. Findings: The layer is without cracks and defects as well as has a considerably higher hardness value compared to the non remelted material. The hardness value increases according to the laser power used so that the highest power applied gives to highest hardness value in the remelted layer. Research limitations/implications: The results present only four choused laser powers by one process speed rate. Also one powder in form of WC was used for alloying with the particle size of 10µm. Originality/value: The originality of this work is based on applying of High Power Diode Laser for improvement of steel mechanical properties. Keywords: Surface treatment; Heat treatment; Hot work tool steel; Laser melting