Effect of high power diode laser surface alloying on wear resistance of high speed steel

Purpose: The following paper presents the results of the influence of laser alloying on structure and properties of the surface of HS6-5-2-5 high speed steel, carried out using a high power diode laser (HPDL). WC, VC, TiC, SiC, Si3N4 and Al2O3 particles powder was used for alloying. Design/methodology/approach: Selection of laser operating conditions is discussed, as well as beam face quality after remelting, hardness, micro hardness test, wear resistant, EDX and X-ray microanalysis results. Findings: Selection of laser operating conditions is discussed, as well as beam face quality after remelting, hardness, micro hardness test, wear resistant, EDX and X-ray microanalysis results. Fine grained, dendritic structures occur in the remelted and alloyed zone with the crystallization direction related to the dynamical heat movement from the laser beam influence zone. The remelted zone structure is characterized by significant martensite dispersion with its laths several times shorter than of those developed during conventional quenching. The fine grained martensite structure is responsible for hardness increase of the alloyed layer. Micro-hardness changes depend up in the effects of the laser beam on the treated surface, and especially in the alloyed layer. Practical implications: Laser technique features the especially promising tool for solving the contemporary surface engineering problems thanks to the physical properties of the laser beam, making it possible to focus precisely the delivered energy in the form of heat in the surface layer. Originality/value: The outcome of the research provides better understanding of the structural mechanisms accompanying laser remelting and alloying.