中文摘要：

以水平连铸球墨铸铁型材LZQT500-7为研究对象,采用正交试验法对等温淬火工艺进行了优化,分析了等温淬火工艺对等温淬火球墨铸铁（ADI）的综合力学性能的影响因素。研究表明,影响奥氏体化温度的升高ADI综合力学性能因素的重要性±次为等温淬火温度、等温淬火时间、奥氏体化温度和奥氏体化时间。随等温淬火温度和奥氏体化时间延长,综合力学性能先提高后下降。而随等温淬火时间延长,综合力学性能提高。最优的ADI处理工艺为奥氏体化温度880℃,奥氏体化时间90 min,等温淬火温度320℃,等温淬火时间150 min,对应的LZQT500-7 ADI型材抗拉强度和冲击韧度可分别高达1464.76 MPa和112.6 J/cm2。

英文摘要：

Taking LZQT500-7 section bar of horizontal continuous casting ductile iron as the research object, the isothermal quenching process was optimized by the orthogonal test method. And the affecting factors of isothermal quenching process on the comprehensive mechanical properties of austempered ductile iron （ADI） were analyzed. The results show that the significance of the factor affecting the comprehensive mechanical properties of the ADI in descending order is anstemperting temperature, austemperting time, austenitizing temperature and austenitizingtime. With the increase of isothermal quenching temperatures, austenitizing temperature and austempering time, comprehensive mechanical properties increase firstly and then decrease. With the increase of isothermal quenching time, the comprehensive mechanical properties inrease. The optimal ADI treatment process is the austenitizing temperature of 880 ℃, austenitizing time of 90 min, the isothermal quenching temperature of 320 ℃, the isothermal quenching time of 150 min. The corresponding tensile strength and impact toughness of the LZQT500-7 ADI section bar are 1464.76 MPa and 112.6 J/cm^2 respectively.