| 摘要 |
A method is disclosed which comprises: (a) forming a ferrous alloy melt consisting essentially of, by weight, 3-4% carbon, 2.0-3.0% silicon, .1-.9% manganese, up to .02% phosphorus, up to .002% sulphur, up to 1% contaminants or impurities, 0-.4% molybdenum, 0-3.0% nickel or copper, and the remainder essentially iron, the melt being subjected to a graphite modifying agent in an amount and for a period of time effective to form either ductile or semiductile iron upon solidification; (b) heat treating the solidification of said melt by austempering to form a matrix consisting substantially of high carbon austenite and ferrite and a cell boundary having unreacted low carbon austenite; (c) heating said austempered iron to a pearlite forming temperature (1200-1300.degree.F) and holding (2-5 minutes) at said temperature to permit the unreacted low carbon austenite to form pearlite; and (d) cooling said heat treated iron to room temperature. |
