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通过对高速车轮钢中TiN夹杂物析出进行热力学分析,得到了车轮钢的液相线和固相线温度及1873K时Ti、N的活度.对TiN生成反应和钢中Ti、N溶度积进行了计算.结果表明:TiN只能在固相中生成,但在本车轮钢Ti、N含量下,固相中也没有TiN生成的条件,只有在钢液凝固前沿,由于Ti、N在两相区的富集,TiN夹杂物的生成反应得以进行.因此,在生产中,适当提高连铸二冷的冷却速率,使钢液快速凝固,减少凝固前沿Ti、N的富集时间,可减少纯TiN的析出.对本实验车轮钢中TiN夹杂的检测结果进行计算分析可知,在正常生产时铸坯冷却速率条件下,将钢中Ti的质量分数控制在3.5×10-5以下、N的质量分数控制在3.1×10-5以下,理论上可以消除TiN夹杂物的析出,改善车轮钢的疲劳性能,提高车轮的使用寿命.
By analyzing the precipitation of TiN inclusions in high-speed wheel steel, the liquidus and solidus temperature of wheel steel and the activity of Ti and N at 1873K were obtained.The reaction of TiN and the solubility of Ti and N in steel The results show that TiN can only be formed in the solid phase, but there is no TiN generation condition in the solid phase due to the content of Ti and N in the wheel steel. Only in the front of solidification of molten steel, Therefore, in the production, the cooling rate of continuous casting and secondary cooling should be increased properly to make the molten steel solidify quickly and the enrichment time of Ti and N in the solidification front can be reduced, which can reduce Pure TiN precipitation.This test wheel steel in the TiN inclusions in the calculation results show that in the normal production of slab cooling rate conditions, the steel content of Ti below 3.5 × 10-5, the mass of N The fractional control of 3.1 × 10-5 or less can theoretically eliminate the precipitation of TiN inclusions, improve the fatigue properties of wheel steel and improve the service life of wheels.