Our blades are surface coated with steam or PVD treatments. PVD system covers high speed steel blades without altering their structural characteristics, because the coating process is made at lower temper­atures than the one used during tempering. Normally the deposited layer is between 2 and 5 microns, im­portant in this phase of coating is the thermal expansion coeffi cient, the thermal conducibility, the hardness, the thermodynamic stability to elevated temperatures; because from these elements depend the fi nal result.