锰球制备条件对氮化反应的影响

利用自制的密闭氮化系统研究不同制备条件的锰球的氮化反应.考察锰粉粒度、成球压力和黏结剂添加量对氮化反应的影响,并测量锰球氮化过程中实时增重和温度曲线.实验结果表明:锰粉粒度由16 ～40目变成60 ～ 80目时,球心温度到达峰值的时间由164 s缩短为101s,球心最大温升由147℃增至233℃,氮化1h的转化率由90.81％增至93.64％;成球压力由266 MPa增至443 MPa,球心峰值温度将提前89 s到达,球心最大温升将提高22℃,氮化1h的转化率由91.59％增至94.92％;黏结剂添加量由1 g增至3 g,氮化1h的转化率由92.90％降至89.80％;正态对数分布的概率密度函数可用来近似拟合转化速率与时间的关系.

Influence of Mn pellet preparation conditions on nitriding reaction

Nitriding reaction of Mn pellets prepared under different conditions was investigated with a self-made air-proofed nitriding system.The effects of Mn particle size,pelletizing pressure and binder content on the nitriding reaction were studied,and the real-time variation curves of temperature and Mn pellet mass were measured.The results show that with the decrease of particle size from 16-40 mesh to 60-80 mesh,the time for the pellet center temperature reaching peak (tp) shifts from 164s to 101 s,the maximum temperature increment at the pellet center (△Tmax) increases from 147 ℃ to 233 ℃,and the conversion ratio at 1 h rises from 90.81％ to 93.64％.With increasing pelletizing pressure from 266 MPa to 443 MPa,tp decreases by 89 s,△Tm=increases by 22 ℃,and the conversion ratio at 1 h rises from 91.59％ to 94.92％.With the increase of binder addition from 1 g to 3 g,the conversion ratio at 1 h drops from 92.90％ to 89.80％.The data points of the conversion rate and the nitriding time can be approximately fitted with the probability density function of the log-normal distribution.