GCr15轴承钢中TiN(C)析出行为热力学分析和研究

通过对TiN(C)生成热力学和动力学计算,分析研究了GCr15轴承钢(0.97％C、1.45％ Cr)凝固过程中TiN(C)夹杂的析出规律以及夹杂物长大的影响因素.研究表明,液相线温度以上,TiN不会析出,只有在液相线至固相线温度之间,当凝固百分数fs≥0.4～0.5,1694～1703 K时TiN析出;整个凝固过程中,TiC在凝固末端有少量析出,当fs≥0.87 ～0.92,1 633～1 643 K时,降低Ti、N含量能够显著降低TiN的析出温度和尺寸.冷却速率不会影响TiN的析出温度,但对夹杂长大也有较为明显的影响.控制析出TiN夹杂的条件为:[Ti]/％≤0.006、[N]/％≤0.004和较大冷却速率.

Study and Analysis on Thermodynamics of TiN(C) Precipitating Behavior in Bearing Steel GCr15

According to the thermodynamic and kinetic calculation of TiN(C),the precipitation rule of TiN(C) inclusions in solidifying process of bearing steel GCr15(0.97%C,1.45%Cr) and the influence factors of inclusion growing are analyzed and studied.Study results show that above liquidus there is no precipitate of TiN,only between liquidus and solid phase curve i.e.as solidification percentage fs≥0.4～0.5 at 1 694～1 703 K the TiN precipitates,and during whole solidifying process there is minor TiC precipitating at solidified front,as fs≥0.87～0.92 at 1 633～1 643 K,with decreasing Ti and N content in steel the precipitated temperature and size of TiN obviously decrease.The cooling rate has not influence on precipitated temperature of TiN but has more obvious influence on inclusion growing.The conditions to control TiN inclusion precipitation are[Ti]/%≤0,006,[N]/%≤0.004 and larger cooling rate.