Casting mould

摘要

A novel casting (1) of ferrous alloy has an internal zone (5) of gray cast iron, enclosed in a peripheral edge zone (6) which has surface hardness more than 400 HV and is of finely or very finely banded pearlite containing inclusions of free graphite (specifically spherical graphite (SG), vermicular graphite or an intermediate structure between spherical and vermicular graphites).