Marek Vostřák
University of West Bohemia, Czech Republic
Title: Diagnostics of laser remelting of thermally sprayed coatings using an infrared camera
Biography
Biography: Marek Vostřák
Abstract
Laser remelting of thermally sprayed coatings is a promising possibility how to improve their functional properties such as wear and corrosion resistance. To achieve the optimal results and the desired depth of remelting, it requires a precise control of laser process parameters. However, any suitable control of laser remelting process by means of infrared measurement was yet not described. In this study, a high-power diode laser was used to remelt the HVOF sprayed stellite coatings. Samples with a diff erent coating/substrate thickness ratio were utilized and by variating the process speed the diff erent depth of remelting was achieved. The remelting process was recorded by the combination of a Long Wavelength Infrared (LWIR) and a Near Infrared (NIR) camera. Th e experiment was designed to fi nd the most suitable method for diagnostics of a remelting process. The possibilities of evaluation of a temperature fi eld in the interaction zone are presented. Th e width of melting pool is calculated from the evaluated temperatures and then correlated with the measured depth of remelting. Th e approximations of their mutual dependence show very high correspondence. It indicates that this measurement can be used for controlling of the depth of remelting, regardless of the samples dimensions.