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应用扫描电镜(SEM)及X射线能谱分析仪(EDS)对真空感应炉熔炼(VIM)和电渣重熔炉熔炼(ESR)的FeCrAl不锈钢中夹杂物的成分、形貌、数量、大小进行统计分析。结果表明,AlN是2个钢锭的主要夹杂物,电渣重熔过程中产生的高熔点稀土化合物可作为AlN析出的异质核心。电渣重熔使自耗电极中尺寸大于10μm的夹杂物基本消失,ESR锭中尺寸小于5μm的夹杂物达到86.7%。电渣重熔减小了AlN的平均尺寸,去除了大尺寸的AlN,使AlN的总面积明显减小。热力学计算结果表明,VIM锭中AlN可以直接在液相中析出;ESR锭中氮含量的降低造成AlN不能直接在液相中析出,随着凝固的进行,[Al]和[N]在残余液相中富集,当凝固分率大于0.615后,AlN才能在凝固前沿的残余液相中析出。
The composition, morphology, amount and size of inclusions in FeCrAl stainless steel by vacuum induction furnace melting (ESR) and vacuum induction melting furnace (ESR) were analyzed by means of SEM and X-ray photoelectron spectroscopy (EDS) analysis. The results show that AlN is the main inclusions of the two ingots. The high melting point rare earth compounds produced during the ESR process can be used as heterogeneous nuclei for AlN precipitation. Electroslag remelting almost disappeared inclusions larger than 10μm in consumable electrode, and the inclusions in ESR ingot with sizes less than 5μm reached 86.7%. Electroslag remelting reduces the average size of AlN, removes the large size of AlN, the total area of AlN was significantly reduced. The results of thermodynamic calculations show that AlN in VIM ingot can be directly precipitated in the liquid phase. The decrease of nitrogen content in ESR ingot causes AlN not to precipitate directly in the liquid phase. As the solidification progresses, [Al] and [N] Phase enrichment, when the solidification fraction is greater than 0.615, AlN in the solidification front of the residual liquid phase precipitation.