For nitrided or nitrocarburized components the following applies:- For areas of components that are not marked with the actual surface hardness must not be more as max. 50 HV 1 below that required. Depending on the coating thickness test forces of HV 0.05 up to HV 30 are permitted.- At areas inaccessible to heat treatment, such as bores, deviations from this limit value are accepted, if no other information is provided.