固态钢加热过程中非金属夹杂物转变研究进展

Transformation of non-metallic inclusions in solid steel during heating process

钢中非金属夹杂物控制是炼钢的关键难题之一,在钢液条件下夹杂物的控制主要是通过夹杂物的改性或聚集长大进而从钢液中去除,在钢的热处理过程中夹杂物的转变机制与液相条件不同,包括新相析出、夹杂物转变和夹杂物结晶。综述了不同钢种热处理过程中夹杂物的转变行为。不同温度下,夹杂物与钢基体之间的热力学平衡发生变化是导致夹杂物成分转变的主要驱动力。不锈钢加热过程中夹杂物由MnO-SiO_(2)向MnO-Cr2O3的转变,铝脱氧钢加热过程中夹杂物由Al_(2)O_(3)-MgO-CaO向Al_(2)O_(3)-MgO-CaS的转变。硅锰脱氧钢加热过程中SiO_(2)-MnO夹杂物成分变化不大,夹杂物的变化行为主要是高SiO_(2)相结晶析出。

Non-metallic inclusion is a key issue of the steelmaking. The control of inclusions in the liquid steel mainly focuses on the inclusion modification, as well as the growth and removal of inclusions in the molten steel. The transformation mechanism of inclusions in solid steels during the heat treatment process is different with that in the liquid steel, including the precipitation of new phase, transformation of inclusions, and crystallization of inclusions. The transformation behaviors of inclusions in various steels were reviewed. The changed equilibrium between the steel matrix and inclusions with temperature was the driving force for the inclusion transformation during the heat treatment process. Inclusions changed from MnO-SiO_(2) to MnO-Cr2O3 in stainless steels during the heat treatment process, while it transformed from the Al_(2)O_(3)-MgO-CaO to Al_(2)O_(3)-MgO-CaS in Al-killed steels. The composition of SiO_(2)-MnO inclusions changed little, and there was the crystallized SiO_(2) phase in inclusions.