等温处理工艺对等温淬火球铁显微组织和硬度的影响

摘要

Austempered ductile iron （ADI） with high-strength and high toughness was created by method of austempering in the 1970s, which is characterized to have a tensile strength over 1000MPa, and an elongation more than 15%. With an orthogonal test and the method of austempering, the effect of the austempering technics on the microstructure and hardness of austempered ductile iron was discussed. It is found that austempered ductile iron which microstructure contains bainite and retained austenite can be gained in all of the designed austempering technics through the experiment. The hardness of samples could be mostly affected by the temperature of austempered, followed by the austenitizing temperature and austenitizing time, and the timing of austempering is proved to have the least influence on the hardness of samples.%上世纪70年代，通过奥氏体等温淬火开发出抗拉强度大于1000MPa、伸长率大于15％的高强度、高韧性等温淬火球铁。利用正交试验法，研究了等温淬火工艺参数对等温淬火球铁显微组织及硬度的影响。结果发现，在设计的试验工艺内全部可以得到以针状铁素体和富碳奥氏体为基体的等温淬火球铁组织；在等温淬火工艺中，等温淬火温度对试样硬度影响最为显著，其次是奥氏体化温度与奥氏体化时间，而等温淬火时间对于试样硬度的影响最小。