Influence Mechanism of Elemental Ce on the Equiaxed Crystal Ratio of 430 Ferrite Stainless Steel

Taking the deep processing properties of 430 ferritic stainless steel as the background， the influence mechanism of rare earth Ce on the equiaxed crystal ratio of 430 ferritic stainless steel was studied. By studying the relationship between the number density， size of rare earth inclusions and equiaxed crystal ratio， the mechanism of the increase of the equiaxed crystal ratio by the rare earth Ce is obtained. The results show that with the increase of Ce content from 0% to 0.039%， the number density of Ce-containing inclusions increases from 0 per/mm2 to 194.37 per/mm2， the equiaxed crystal ratio increased from 28.3% to 84.4%， and the corresponding equiaxed grain size decreased from 1 910 μm to 310 μm. Based on thermodynamic calculations， with the increase of Ce content， SiO2 inclusions are gradually modified to Ce-O， and the heterogeneous nucleation of Ce inclusions on ferrite is the main reason for the increase in equiaxed grain rate of 430 ferritic stainless steel. The CAFE calculation model of PROCAST also indicates that as the number density of nucleating agent particles increases， the equiaxed grain rate gradually increases， and the theoretical calculation results are basically consistent with the actual observation results.