Cast iron valve seat insert - contg. copper particles to give adhesive wear resistance when using lead free fuels in motor car engines

摘要

Cast iron internal combustion engine components contg. 4-14% copper (pref. 4-7% Cu or 7-14% Cu) and 2.5-3.8% total carbon, 0.2-3.5% Si, 0.2-1.5% Mn, 0.05-0.9% P, 2.5% max. Cr, 2.5% max ni, 1.0% max V, rest Fe. This alloy of grey or white cast iron is especially resistant to adhesive wear. Up to about 2% of copper is in solution in the structure but beyond this amount it is present in an elementary form. With 4-7% Cu, the cast iron contains a finely dispersed ppt. of elementary Cu, whereas with 7-14% Cu, larger particles of Cu are present. This ppt. of Cu hinders the adhesive wear observed between valves and valve seats when using Cu free cast iron and burning lead-free fuel.