镍基耐蚀合金C-276铸锭元素偏析和均匀化工艺

Microsegregation and homogenization of nickel base corrosion resistant alloy C-276 ingots

  • 摘要: 利用光镜、扫描电镜和能谱仪等显微组织分析方法研究了镍基耐蚀合金C-276经真空冶炼+电渣重溶后铸锭的枝晶特点和元素偏析情况,根据残余偏析指数模型计算结果选取了四种均匀化实验制度,并通过均匀化实验后的组织分析和Gleeble1500试验机热模拟锻造实验验证,最终确立了适合C-276合金的均匀化工艺.结果表明:合金中偏析程度最严重的元素为Mo;在选取的四种均匀化制度中,采用1170℃下加热20h的处理方式不仅可以较好地实现成分均匀化,还能保证晶粒尺寸不过度长大,从而确保合金的热加工塑性,是最为合理的均匀化制度.实验也证明利用残余偏析指数模型,计算结果与实验结果基本吻合,在预测和评价C-276合金均匀化工艺上是可信的.

     

    Abstract: The microstructure and microsegregation of nickel base corrosion resistant alloy C-276 vacuum-induction-melting and electroslag-remelting ingots were studied by optical microscope, scanning electron microscopy and energy dispersive X-ray spectroscopy. Based on the calculated results of the residual segregation parameter model, four homogenizing treatments were tested. Microstructure analysis and thermal compression test with a Gleeble 1500 machine were used to verify the effect of homogenizing treatment. The results show that the severest segregated elements in C-276 is Mo, and 1170℃/20h is the most appropriate treatment for C-276 alloy in the study as it ensures homogenizing effect and reasonable grain size for optimizing the hot-working plasticity of the alloy. It is also proved that homogenization process of C-276 alloy can be effectively predicted and evaluated by the residual segregation parameter model, which basically agrees with the experimental results.

     

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