PISTON FOR A RECIPROCATING-PISTON INTERNAL COMBUSTION ENGINE PROVIDED WITH HARDENED PISTON RING GROOVES

摘要

The invention relates to a piston for a reciprocating-piston internal combustion engine which is made of a nitride-forming base alloy and comprises a piston top part (1) provided with several circulatory piston ring grooves (4) and a piston fire land. At least the piston top ring groove (4a) arranged near a combustion chamber is provided with wear-protected hardened slot flanks (5a, b). The aim of said invention is to optimise said piston in such a way that the top part thereof, in particular the top piston ring grooves, exhibits an extended operational lifetime. For this purpose, at least the external surfaces of the piston top part comprising the wear-protected hardened slot flanks and the piston fire land are provided with an additional wear-protective and anti-corrosive layer (7) in the form of a nitride layer which is producible by converting the nitride-forming base alloy by plasma-nitriding or plasma-nitrocarburising in a nitrogen or nitrogen and carbon atmosphere in such a way that the hardened slot flanks are additionally protected by said nitride layer (7)