Study on Ti-Ce Complex Inclusions in Ductile Cast Iron
The inclusions in spheroidal graphite iron spheroidized by RE-Mg were observed by SEM.The forming process of Ti-Ce-S compound inclusions was analyzed combining thermodynamic calculation and kinetic conditions.The results show that the block Ti-Ce-S compound inclusions distributes in the phase boundaries of pearlite and ferrite,whose size is 3 μm.CeS provides heterogeneous nucleus for the formation of TiS during spheroidization.The reducing reaction of Ce and TiS is the main factor to promote the formation of Ti-Ce-S compound inclusions.The Ti-Ce may also compound with La,Ba,Mg etc and form inclusions,such as Ti-Ce-La-S,Ti-Ce-Ba-S,Ti-Ce-Ba-Si-S,Ti-Ce-V-C and Ti-Ce-La-Mg-C-N-S.The sufficient reaction among the elements like Ti,Se etc and the effective removal of this kind of inclusions are main factors to ensure spheroidization effect.