Grinding of Hard Metal Wear Protection Coatings

The automotive industry faces the challenge of meeting the climate protection targets set by legislators. In addition to meeting CO2 targets, climate protection also involves reducing environmentally harmful particulate matter, which is produced among other things during the braking process with conventional cast-iron brake discs. To reduce particulate matter by 70-90%, wear-resistant coatings of hard metal, such as tungsten carbide in stainless steel matrix, are applied to brake discs by laser cladding. In addition to corrosion protection, these coatings have the advantage of producing only a small amount of environmentally harmful particulate matter during the braking process. The process-related inhomogeneity in the material properties and shape tolerances after laser cladding necessitates post-processing by means of a double-sided surface grinding process. The double-sided machining is carried out due to higher stability through the bracing as well as higher economic potential through parallel machining from both sides. So far, the grinding process of hard metal coatings, such as tungsten carbide in stainless steel matrix, has not been systematically investigated. Due to the novelty of the application, it is still unknown to what extent the process input parameters, such as carbide content, process kinematics and parameters, and grinding wheel specification, have an influence on the cutting process, grinding forces, and temperature, grain loading, and chip formation. In particular, the two-phase structure of the material with different material properties creates a major challenge for the machining process in terms of chip formation and mechanical load from the grinding wheel.

The aim of this subproject is to identify the influence of the process input parameters on chip formation as well as the process condition and process result variables during the grinding of carbide-coated components. The main focus is on the machining mechanisms.