Comprehensive Evaluation of Properties of Laser Welded Overlay of Powder H13 Steel on Structural S355 Steel and on H11 Tool Steel

Laser hard overlaying is an advanced, perspective technology with wide industrial applications, for example dies. The aim is to improve surface properties like wear resistance using special layers of powder sintered or remelted by laser beam. At present, dies are manufactured by machining with following bulk heat treatment, which is an expensive process particularly due to use of expensive high-alloyed tool steels. Repairs performed using arc or plasma welding introduce a big amount of heat to the part, which can cause dimension changes and material degradation, These methods often fail also due to low weldability of the materials. An advantage of laser overlaying is minimization of these difficulties. The paper contains a comprehensive evaluation of several types of hard overlayed powder of H13 tool steel on a S355 structural steel and on H11 tool steel using laser beam. Macro- and microstructure, hardness and fatigue resistance are evaluated including fatige damage mechanisms. Results are completed with basic measurement of residual stresses using destructive strain-gauge methods. Fatigue resistance is sensitive on surface and subsurface defects, which can significantly reduce endurance limit.