Mo含量对空调滑片用球墨铸铁组织与性能的影响

Effects of Mo Content on Microstructure and Properties of Ductile Cast Iron for Air Conditioning Slider

研究了含钼量和等温淬火温度对含碳化物等温淬火球墨铸铁(CADI)显微组织和力学性能的影响。结果表明,随着Mo含量增加,铸态球墨铸铁中石墨数量减少,珠光体数量和碳化物数量增多,碳化物形貌逐渐从弥散分布的细小块状转变为粗大的块状或者长条状;5种Mo含量的等温淬火态CADI试样的组织都为针状铁素体、球状石墨、碳化物和少量残余奥氏体。等温淬火温度为275℃时,随着Mo含量的增多,针状铁素体数量不断增多,而残余奥氏体含量不断减小,CADI试样的室温冲击功先增加而后减小,洛氏硬度逐渐增大,平均磨损量和磨损率逐渐减小。随着等温淬火温度的升高,含0.43%Mo的CADI试样冲击功升高而洛氏硬度减小,平均磨损量和磨损率增大。空调滑片用球墨铸铁适宜的Mo添加量为0.43wt%,等温淬火温度为275℃。

The effects of molybdenum content and isothermal quenching temperature on the microstructure and mechanical properties of carbidic austempered ductile iron were studied.The results show that,with the increase of Mo content,the amount of graphite in the cast nodular cast iron decreases,and the number of pearlite and carbides increases.The morphology of carbides gradually changes from dispersed small block to coarse block or long strip.The microstructure of the isothermal quenched CADI samples with different Mo content are acicular ferrite,spheroidal graphite,carbides and a small amount of retained austenite.When the isothermal quenching temperature is 275℃,with the increase of Mo content,the number of acicular ferrite increases and the content of retained austenite decreases,the impact power at room temperature of CADI increases at first and then decreases,the Rockwell hardness increases gradually,and the average wear rate and wear rate decrease gradually.With the increase of isothermal quenching temperature,the impact power of the CADI sample with 0.43%Mo increases while the Rockwell hardness decreases,and the average wear and wear rate increase.The appropriate Mo content of nodular cast iron for air-conditioning slide is 0.43wt%,and the isothermal quenching temperature is 275℃.