含铬等温淬火球墨铸铁组织性能研究

Study on Microstructure and Properties of Austempered Ductile Iron Containing Cr

针对含铬球墨铸铁厚壁件球化不良,等温温度对组织和性能影响不明确的问题,添加了0.2%的重稀土钇在球墨铸铁中,并设计了5种等温淬火温度用于研究等温转变温度对含铬球墨铸铁组织和性能的影响。结果表明,重稀土处理后,石墨球尺寸均一,分布均匀,常规处理后球墨铸铁中出现的大尺寸石墨球消失,钇的添加有效的解决了含铬球墨铸铁球化衰退的问题。低温等温淬火后,球墨铸铁中含有少量的马氏体,随着温度的升高,奥铁体的尺寸逐渐增加,冲击韧度逐渐升高,硬度逐渐减低。300℃等温淬火后,含铬球墨铸铁可获得最优的耐磨性。

In order to solve the problems of poor nodularity and microstructure and properties of thick section SG iron containing Cr,0.2%Yttrium rare earth was added for nodulazition treatment,and five different austempering temperature were selected to study the effect of austempering temperature.Results show that addition of yttrium improved nodularity and nodule count.Low austempering temperature results in a small amount of martensite.With increasing austempering temperature,elongation,impact value and strength are increased,hardness is decreased.Austempering at 300℃can obtain optimized wear resistance.