等温淬火球铁热处理工艺参数的优化方法

摘要

等温淬火球铁(ADI)作为性能可设计材料,其热处理工艺参数的优化设计是开发性能优良的ADI材料的关键.在不改变热处理生产条件的基础上,采用不同的等温淬火温度和时间,分别制作出不同力学性能检测数据的各种试样,并将实验数据用于建立热处理工艺参数与力学性能的模糊减法聚类函数模型.以抗拉强度、冲击韧度、硬度等力学性能为用户需求目标,等温淬火温度和时间为可设计变量,采用NSGA Ⅱ遗传算法作为优化算法进行优化计算.结果表明:用这种方法设计满足ASTM3,ASTM4级力学性能要求的热处理参数,可以得到最佳的等温淬火预测温度和时间分别为333℃,136 min和312℃,132 min.%Austempered ductile iron (ADI) is a performance designable material. The optimization design of its heat treatment parameters is the key to develop a good performance ADI material. The fuzzy subtractive clustering function model about the heat treatment parameter and mechanical properties was built using experiment data on the base of no changing the production conditions of heat treatment, various ADI samples with test data of different mechanical properties were made at the different austempering temperatures and time. The heat treatment parameters were chosen by taking tensile strength, impact toughness and hardness as objective of eustomers demand, taking austempering temperature and time as designable variables, and using the NSAG Ⅱ genetic algorithm as optimization algorithm. The results show that this method can satisfy the parameters of heat treatment required by mechanical properties ASTM grade 3 and 4, and can get the best prediction austempering temperature and time ,which are respectively 333 ℃ ,136 min and 312 ℃ ,132 min.