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本文用含Nb、V、Ti等元素的42CrMo钢研究了未溶碳氮化物的r/f与奥氏体晶粒大小之间的关系,用车轴钢研究了加热速度对奥氏体晶粒长大倾向的影响以及用GCr15钢研究了不平衡组织加热对奥氏体晶粒的异常长大现象。所得结果均难以用Zener及Gladman所提出的有关奥氏体晶粒半径与r/f之间的关系式进行解释。为解释所观察到的现象,对Zener及Gladman公式进行了讨论。指出Zener公式之所以与实验情况不符是因为式中的R不是奥氏体晶粒半径而是界面曲率半径。Gladman公式之所以与实际情况不符是因为推导驱动力时的假设有误。本文导出了界面曲率半径R与界面两侧晶粒半径ρ及ρ′之间的关系为: R=ρ/2cos(60°+90°/πZ)式中Z=ρ′/ρ°由界面能提供的推动晶界迁移的驱动力P力: P=4σcos(60°+90°/πZ)/ρ奥氏体晶粒长大终止时晶粒半径ρ与r/f之间的关系为: ρ=8r/3f 2cos(60°+90°/πZ) 用导出的公式讨论了所观察到的奥氏体晶粒长大的种种异常现象并核算了Koul所得的数据,所得结果与实测值符合得较好。
In this paper, the relationship between r / f of undissolved carbonitride and austenite grain size was investigated by using 42CrMo steel containing Nb, V, Ti and other elements. The effect of heating rate on austenite grain length Large propensity and GCr15 steel to study the abnormal growth of austenite grains caused by unbalanced heating. The results obtained are difficult to interpret using the relation between austenite grain radius and r / f proposed by Zener and Gladman. To explain the observed phenomena, the Zener and Gladman formulas are discussed. It is pointed out that the reason why the Zener formula does not accord with the experimental situation is that R is not the austenite grain radius but the interface radius of curvature. The reason why the Gladman formula is inconsistent with the actual situation is that the assumptions made when deriving the driving force are incorrect. In this paper, we derive the relationship between the radius of curvature R of the interface and the ρ and ρ of the grains on both sides of the interface as: R = ρ / 2cos (60 ° + 90 ° / πZ) where Z = ρ ’ P = 4σcos (60 ° + 90 ° / πZ) / ρ The relationship between the grain radius ρ and r / f at the end of the growth of the austenite grain is as follows: ρ = 8r / 3f 2cos (60 ° + 90 ° / πZ) The observed anomalies of austenite grain growth were discussed using the derived equations and the Koul data were calculated and the results obtained agree well with the measured values better.