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采用高频感应加热设备熔配含Ni量为20%~60%的高镍合金铸铁样品,研究了Ni含量对铸铁基体组织、石墨形态及合金硬度的影响。结果表明,在高Ni合金铸铁中,随着Ni含量的增大,一方面,合金的石墨化能力显著增强,可以获得无渗碳体相的凝固组织,石墨形态由粗大片状依次向细小片状→点状→粗化点状转变;另一方面,合金结晶温度区间变窄,成分过冷倾向减小,奥氏体枝晶分枝能力减弱,形成了形态不甚发达的粗大枝晶乃至等轴晶组织,在Ni余量为20%及以上时高镍合金铸铁的硬度呈现出单调减小的趋势。
The high nickel alloy cast iron with 20% ~ 60% Ni was melted by high frequency induction heating equipment. The effects of Ni content on the microstructure and morphology of the cast iron matrix and the hardness of the alloy were studied. The results show that on high Ni alloy cast iron, with the increase of Ni content, on the one hand, the graphitization ability of the alloy is significantly enhanced, and solidified structure without cementite phase can be obtained. The graphite morphology changes from coarse flake to fine flake Shape → point → roughening point transition; on the other hand, the alloy crystallization temperature range narrowing, the tendency of the composition to reduce the overcooling, austenite dendrite branching ability weakened, the formation of the morphology of less developed dendrite and even In equiaxed grain structure, the hardness of high-nickel alloy cast iron decreases monotonically when Ni balance is 20% and above.