ENHANCEMENT OF TRIBOLOGICAL PROPERTIES BY LASER METAL DEPOSITION OF AISI H13 AND WC COATINGS

In the last few years, the requirements that manufacturers demand in terms of material specifications have risen considerably. The highly competitive industry leads to the development of new materials by means of alternative manufacturing processes, such as Metal Matrix Composites (MMC) manufactured by Laser Metal Deposition (LMD). Coatings made from metal matrix composites reinforced with ceramic particles are of particular interest in the manufacturing of dies and molds for hot stamping processes, as they allow improving the wear behavior even when working in aggressive environments. This permits increasing the lifespan of these high added value components. To analyze this kind of coating, monolayer specimens constituted by hot work tool steel (AISI H13) and tungsten carbide (WC) have been deposited. The high hardness of the WC may lead to a considerable improvement in the tribological and mechanical properties. In order to characterize and quantify this enhancement, wear tests have been performed in coatings manufactured with different concentrations of WC. In addition, the metallurgical integrity of the deposited clads has been analyzed. Lastly, the hardness of the clads has been measured. It has been concluded that this kind of multi-material coatings leads to an increase of the wear resistance and hardness. However, it is necessary to control the dilution of the reinforcing phase in the matrix, and to use adequate post-processing methods since, given the high hardness of the clads, the tendency to crack also increases. Keywords: Metal Matrix Composites, Laser Metal Deposition, hardness, wear, die and mold, hot stamping, tungsten carbide, hot work tool steel, metallurgical integrity