低碳当量对灰铸铁组织和性能的影响

Effect of Low Carbon Equivalent on Microstructure and Properties of Gray Cast Iron

随着柴油发动机功率的不断提高,对灰铸铁缸体材料提出了越来越高的性能要求。本文通过金相显微镜、扫描电子显微镜、布氏硬度计、电子万能试验机和激光导热仪对低碳当量(CE≤3.9%)灰铸铁的组织和性能进行研究。探究碳当量(3.2%~3.8%)对灰铸铁的显微组织、力学性能及导热性能的影响。结果表明:当碳当量由3.8%降至3.2%,石墨形貌变得细小弯曲,石墨长度降低;珠光体层片间距变得致密均匀,抗拉强度达到385.9MPa;随着碳当量降低,材料的导热性能对温度的依存性也逐渐降低。

With the continuous improvement of diesel engine power, higher and higher performance requirements are put forward for gray cast iron cylinder block materials. The microstructure and properties of low carbon equivalent(CE≤3.9%)gray iron was studied by metallographic microscope, scanning electron microscope, Brinell hardness tester, electronic universal sampler and laser thermal conductivity tester. The effects of carbon equivalent(3.2%-3.8%) on the microstructure, mechanical properties and thermal conductivity of gray cast iron were explored. The results show that when the carbon equivalent is reduced from 3.8% to 3.2%, the morphology of graphite becomes fine and curved, and the graphite length decreases;the distance between pearlite layers becomes dense and uniform, and the tensile strength reaches 385.9 MPa;with the decrease of carbon equivalent, the dependence of thermal conductivity on temperature decreases gradually.