Solidification Structure Refining of 430 Ferrite Stainless Steel With TiN Nucleation

The thermodynamics of TiN precipitation in liquid steel of 430 ferrite stainless steel has been calculated to find out the condition of TiN precipitation during the initial solidification stage. The difference in the solidification structure of 430 ferrite stainless steel has been discussed through comparative tests of vacuum induction furnace melting with different contents of Ti. It has been found that the equiaxed grain proportion can be increased from 20% to 69% as the content of Ti from 0. 1% up to 0. 4%. The size of the TiN particles precipitated is 1–3 μm and the number of TiN particles is about (200–300)/μm2. It is found that the effect of using TiN to refine the solidification structure has been confirmed under the strict process condition used for 430 ferrite stainless steel.