过共析帘线钢中Ti夹杂的析出热力学与形成机制

过共析帘线钢中析出的含Ti夹杂对钢丝拉拔性能产生有害影响,研究钢中Ti夹杂的析出行为对夹杂物性质控制以及钢材质量提高具有重要意义.考虑夹杂物析出对凝固前沿溶质浓度和温度影响下,基于传统Ohnaka模型建立了相应的耦合模型并以此计算了92级过共析帘线钢中TiN夹杂的析出热力学.结果表明,耦合模型条件下TiN夹杂的析出时间...

Precipitation thermodynamics and formation mechanism of Ti inclusions in hypereutectoid tire cord steel

Ti inclusions precipitated in hypereutectoid tire cord steel had severe impacts on the drawing performance of steel. An investigation on the precipitation behavior of Ti inclusions would play essential roles in the control of inclusion properties and the improvement of steel quality. Considering the influences of inclusion precipitation on the solute concentrations and temperature during the solidification process, a corresponding coupling model was constructed based on the classical Ohnaka model, and the precipitation thermodynamics of TiN in 92A hypereutectoid tire cord steel was calculated. The results generated by the coupling model indicate that the precipitation time of TiN is earlier than that derived from the classical Ohnaka model. The greater the cooling rate is, the earlier the precipitation time will be. After the precipitation of TiN, N concentration increases, while Ti concentration decreases in the solidification front. The results also indicate that Ti inclusions that existed in steel ingot are complicated and diverse, which not only include single phase TiN, but also TixOy TiN, TiN MnS, and TixOy TiN MnS compound inclusions. Through the calculation, it is also found that TixOy preferentially precipitates in molten steel; and then as solidification progresses, TiN and MnS precipitate successively. Combining with the atomic mismatch calculation method, the possible formation mechanisms of compound Ti inclusions in steel are proposed.