Wear-resistant piston ring for IC engine - has molybdenum surface contact layer and softer coating on flanks to contact soft metal piston grooves

摘要

The contact surfaces of the piston ring has an e.g. molybdenum coating with good running properties and wear resistance. The side of the ring have a softer layer comprising sulphurated iron sulphide (FeS) layer 2-8 micro metres thick. The ring is made from e.g. spheroidal graphite cast iron G6 with a height of 1.75 mm and a radial depth of 4.6 mm. The finished contact surface is imparted in an electro-lytic bath with a composition of e.g. 75% KSCN and 25% NaCN. A current density on the anodic piston ring of approx 3.2 A/dm2 is employed for an immersion time of about 5 min.