Effects of Ti Content and Cooling Rate on Inclusions with Ti in Ductile Iron

The effects of Ti content and cooling rate on morphology, average size and distribution of inclusions with Ti in ductile iron were studied. The results show that when the mass fraction of Ti increased from 0.005% to 0.025%, the average size of inclusions increased from 2.14 μm to 3.04 μm, when the cooling rate increased from 1 ℃·s-1 to 6 ℃·s-1, the average size of the inclusions in ductile iron with 0.015wt% Ti decreased from 4 μm to 1.5 μm. Ti could form inclusions with RE, Ba, Mg and so on, and the lower the Ti content and the larger the cooling rate, the easier the single-phase inclusion forming. Most of these inclusions were lump and had clear angles, while small amount of indusions were spherical. The size of majority inclusions was between 1.5 μm and 7 μm and they distributed in pearlite, ferrite and at grains boundaries.