电磁搅拌对GH3030高温合金铸态组织的影响

通过试验研究了电磁搅拌对高温合金GH3030铸坯的凝固组织及凝固过程中溶质分布的影响。GH3030合金的凝固微观组织为单相奥氏体,电磁搅拌可以打碎枝晶、促进形核,明显细化其晶粒,得到组织致密,晶粒细小的凝固组织。没有电磁搅拌的情况下,铸坯的宏观偏析和微观偏析都比较严重。通过施加电磁搅拌,熔体的流动使得熔体内的传热得到改善,凝固前沿温度梯度变小,同时促进溶质富集区液体与熔体其他部分的混合,从而减轻了Cr元素在铸坯中的宏观偏析和微观偏析,使Cr元素分布的更加均匀,铸坯质量得到提高。

Effect of Electromagnetic Stirring on As-cast Microstructure of Superalloy GH3030

Effects of electromagnetic stirring on the solidification structure and the solute distribution in the superalloy GH3030 billet during solidification process were experimentally investigated and analyzed.The solidification microstructure of GH3030 is composed of the single-phase austenite.Through electromagnetic stirring(EMS),the dendrites are broken and the nucleation process is accelerated,which are responsible for the refinement of grains and compactness of the solidification structure.Without EMS,the serious microsegregation and the macrosegregation can be observed.With the EMS,temperature gradient at the solidification front is decreased as a result of improving heat transfer behavior in the melt during melt flow,and mixture of the melt with solute enrichment zone with the other melt zone is enhanced.As a result,the macrosegregation and the microsegregation of chromium in the billets are improved,and the chromium in the ingots with EMS is more uniformly distributed,improving significantly the quality of billets.