【摘要】 通过模拟渗碳试验,研究了Nb对齿轮钢20Cr Mn Ti晶粒粗化行为的影响。结果表明,由于析出含Nb析出相,Nb能显著提高在模拟渗碳过程中的晶粒粗化温度。晶粒粗化温度由析出相的体积分数和析出相的尺寸决定。当模拟渗碳温度较低时,时间对析出相尺寸影响不明显;当渗碳温度较高时,延长时间析出相明显粗化。因此,对于Nb含量较低的试样,1 h和6 h模拟渗碳的晶粒粗化温度接近;而对于Nb含量较高的试样6 h模拟渗碳的晶粒粗化温度比1 h的低。更多还原

【Abstract】 The effect of niobium on austenite grain coarsening behavior of 20 Cr Mn Ti was investigated by using pseudo-carburizing experiment. Results show that the grain coarsening temperature is increased significantly by niobium because of its precipitates. The grain coarsening temperature is determined by both volume and sizes of the participates. The sizes of the participates is not affected by time when pseudo-carburizing temperature is relatively low; while the sizes increase dramatically with extending the time when pseudo-carburizing temperature is relatively high. Therefore the grain coarsening temperatures for 1 h and 6 h are the same for the specimens with low content of niobium; while the grain coarsening temperature for 6 h is lower than that of 1 h for the specimens with high content of niobium.更多还原