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研究了等温淬火工艺对含铬球墨铸铁组织、硬度、冲击性能和耐磨性的影响。结果表明:奥氏体化温度升高,能促进球状石墨长大,增加残留奥氏体含量。淬火后组织主要为球状石墨、针状贝氏体、含铬碳化物及残留奥氏体。当淬火等温温度在240~270℃,随着等温温度升高,试样硬度和耐磨性均降低;在240℃等温淬火时冲击韧度较低,继续升高等温温度,冲击韧度先增大后降低;当试样经910℃×80 min奥氏体化、270℃×180 min等温淬火后,含铬球墨铸铁的硬度可达54.1 HRC、冲击韧度αk可达8.1 J·cm~(-2),有较好的耐磨性。
The effects of austempering process on microstructure, hardness, impact properties and wear resistance of chromium-containing ductile iron were studied. The results show that the increase of austenitizing temperature can promote the growth of spherical graphite and increase the content of retained austenite. After quenching the organization mainly spherical graphite, acicular bainite, chromium carbide and retained austenite. When the isothermal quenching temperature is in the range of 240-270 ° C, the hardness and wear resistance of the samples decrease as the isothermal temperature increases. The impact toughness of the samples decreases at isothermal quenching at 240 ° C. The isothermal temperature continues to increase and the impact toughness increases first After austenitizing at 910 ℃ × 80 min and isothermal quenching at 270 ℃ × 180 min, the hardness of chrome-plated ductile iron can reach 54.1 HRC and the impact toughness αk can reach 8.1 J · cm ~ ( -2), have better wear resistance.