AUSTEMPERED CAST IRON ARTICLE AND A METHOD OF MAKING THE SAME,申请号CA20032497760-传众专利搜索

AUSTEMPERED CAST IRON ARTICLE AND A METHOD OF MAKING THE SAME

申请公布号：CA2497760(A1)

申请号：CA20032497760

申请日期：2003.08.29

申请公布日期：2004.03.18

申请人：

INTERMET CORPORATION

发明人：FITZGERALD, DAVID CARROLL;DRUSCHITZ, ALAN PETER

分类号：C21D1/18;C21D1/20;C21D1/607;C21D5/00;C21D9/30;(IPC1-7):C21D5/00;C22C37/04

主分类号：C21D1/18

摘要：A machinable austempered cast iron article has improved strength, machinability, fatigue performance, and resistance to environmental cracking . A method of making the machinable austempered cast iron article includes austenitizing an iron composition having a substantially pearlitic microstructure in an intercritical temperature range of between 1380~F and 1500 ~F. This produces a ferritic plus austenitic microstructure. The ferrit ic plus austenitic microstructure is quenched into an austempering temperature range of between 575 ~F and 750 ~F within 3 minutes to prevent formation of pearlite. The ferritic plus austenitic microstructure is then austempered in the austempering temperature range of between 575 ~F and 750 ~F to produce a microstructure of a continuous matrix of equiaxed ferrite with islands of austenite. Finally, the microstructure of the continuous matrix of equiaxed ferrite with islands of austenite is cooled to ambient temperature to produc e the machinable austempered cast iron article.