Cast iron valve seat inserts - with large graphite content to give adhesive wear resistance when using lead free fuels in motor car engines

摘要

Cast iron internal combustion engine components contg. more than 3.0% graphite in a total carbon content of 3.8% min. (pref. 3.2% in 4.05%), and 0.5-3.0% Si, 0.2-1.5% Mn, 0.04-0.7% P, 0.05-1.5% Sn, 0.1-2.5% Ni, 0.05-1.5% Mo, rest Fe. The basic structure can be pearlitic or a hardened and tempered structure ranging from pearlite to martensite, in both cases with a graphite content over 3%. The presence in the structure of graphite above the eutectic amount confers exceptional resistance to the adhesive wear of mating surfaces, e.g. valves and valve sealts, even when using lead-free petrol.