低牌号球墨铸铁风冷强化工艺的试验研究

Study on wind cooling strengthening process of nodular cast iron

研究了风冷热处理对低牌号球墨铸铁(QT450-10)组织和性能的影响。利用对比法和网格法对珠光体组织进行了定量分析,并测试了风冷前后球墨铸铁的力学性能,分析了球墨铸铁风冷强化的微观机制。结果表明,QT450-10球铁经风冷强化以后,其内部组织由原来85%的铁素体基体转变成90%以上的珠光体,且经测量的珠光体片层间距仅为0.45μm,这种细珠光体的片层结构是导致球墨铸铁的抗拉强度由原来的495 MPa增至905 MPa的主要原因。

The effect of wind cooling on microstructure and mechanical properties of nodular cast iron （QT450-10） was investigated. The quantitative analysis of pearlitic structure was performed by pairing method and grid method. The mechanical properties of QT450-10 nodular cast iron were tested and the micromechanism of improving mechanical properties by wind cooling was analyzed. The results show that 85% of ferrite in nodular cast iron is transformed into 90% of pearlite whose interlamellar spacing is only about 0. 45 μm. This fine pearlite lamellar structure leads to the tensile strength increase from 495 MPa to 905 MPa after wind cooling.