Manufacture of hardened iron camshaft castings

摘要

Hardened-surface camshaft castings particularly suitable for highly stressed service are manufactured from compacted graphite iron. A low alloy content and interrupted austempering treatment are used to develop a wear resistant bainitic microstructure containing retained austenite on the surface of the castings and the sections adjacent thereto. The preferred composition range of the compacted graphite iron is:- Carbon 3.2% to 3.6% Silicon 2.0% to 2.6% Manganese 0.5% to 0.9% Copper 0.15% Magnesium 0.02% to 0.04% Titanium 0.05% to 0.1% Sulphur 0.02% Phosphorus 0.05% Iron & Impurities the balance y