Ti-IF钢非金属夹杂物形核热力学和演变机理

通过热力学计算与SEM-EDS检测对酒钢BOFLFRHCSP工艺Ti-IF钢夹杂物形核的热力学进行了研究。结果表明,在Ti-IF钢中夹杂物形核主要是非均匀形核,最易形成TiN,其次为CaO,然后为Al_2O_3。温度升高有利于Al_2O_3、CaO的形成;TiN的形成受温度影响较小。Ti-IF钢中w(Als])控制为0.027%~0.055%时,w(Mg])只需大于0.000 015%,就会有镁铝尖晶石MgO·Al_2O_3(MA)析出。Ti-IF钢中夹杂物演变主要有3种途径,分别为尖晶石与硅酸钙的复合夹杂Al_2O_3→MA→MgAlCaSi、低熔点的铝酸钙夹杂Al_2O_3→CaO·6Al_2O_3(CA_6)→CaO·2Al_2O_3(CA_2)→CaO·Al_2O_3(CA)→3CaO·Al_2O_3(C_3A)/12CaO·7Al_2O_3(C_(12)A_7)以及钛的复合物或钛的化合物Al_2O_3→TiOx→Al_2O_3·TiOx和Ti→TiN/Ti(C,N)。

Nucleation thermodynamic and evolution of non-metallic inclusions in Ti-IF steel

The thermodynamics of inclusion nucleation in Ti-IF steel，which was produced by BOFLFRHCSP 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).