Nucleation thermodynamic and evolution of non-metallic inclusions in Ti-IF steel
ZOU Ming1，XU Rong-huan2，LI Ji-peng1,2，CHENG Shu-sen2
（1. Carbon Steel and Thin Slab Rolling Plant of Hongxing Iron and Steel Co., Ltd.， JISCO， Jiayuguan 735100， Gansu， China 2. School of Metallurgical and Ecological Engineering， University of Science and Technology Beijing， Bejing 100083， China）
Abstract：The thermodynamics of inclusion nucleation in Ti-IF steel，which was produced by BOFLFRHCSP process of JISCO， was studied by thermodynamic calculation and SEM-EDS detection. The results showed that the nucleation of inclusions in Ti-IF steel was mainly heterogeneous nucleation，and TiN was most easily formed，followed by CaO and Al2O3. The increase of the temperature was beneficial to the formation of CaO and Al2O3，however，the formation of TiN was less affected by the temperature. When w(［Als］) in Ti-IF steel was controlled within 0.027%-0.055%，MgO·Al2O3(MA) spinel will precipitate just when w(［Mg］) was larger than 0.000 015%. There were three routes for the evolution of inclusions in Ti-IF steel，the inclusions evolve into the spinel and calcium silicate composite inclusion Al2O3→MA→MgAlCaSi，the inclusions evolve into the calcium aluminate inclusion with low melting point Al2O3→CaO·6Al2O3(CA6)→CaO·2Al2O3（CA2）→CaO·Al2O3（CA）→3CaO·Al2O3（C3A）/12CaO·7Al2O3（C12A7），the inclusions evolve into the titanium complex or titanium compounds Al2O3→TiOx→Al2O3·TiOx and Ti→TiN/Ti(C，N).
2017, Vol. 27 
