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本文对10MnNb钢热形变奥氏体的再结晶和沉淀过程进行研究,并与16Mn钢作对比,以判别铌的影响。铌的微量添加使形变奥氏体的动态回复与再结晶过程得到延缓。无铌钢动态再结晶的表现激活能为30.4kcal/mole,而含铌钢则为74.9kcal/mole。铌的添加亦明显地阻碍热形变奥氏体的静态回复与再结晶;在800℃时,含铌钢的静态再结晶几乎完全被抑制。形变奥氏体的再结晶有两种方式:一种是应变诱导晶界迁移,但不是主要的方式,主要的是通过原奥氏体晶界或退火孪晶界上形核并长大。形变奥氏体中的应变诱导碳化物沉淀和未形变奥氏体中碳化铌的静态沉淀研究表明:0.357的应变量可使碳化物沉淀过程加速两个数量级。再结晶过程改变了沉淀粒子的尺寸与分布。这是由于再结晶前沿界面引起沉淀粒子快速粗化所致。本文对再结晶和沉淀过程的交互作用的微观机制进行了探讨。铌抑制再结晶过程的原因是由于溶质原子对晶界或亚晶界的拖曳效应以及碳化铌沉淀粒子对这些晶界的钉扎作用。根据铌对热形变奥氏体再结晶与沉淀过程的影响规律,对优选10MnNb钢的控制轧制工艺参数作了分析并提出了建议。
In this paper, the recrystallization and precipitation of 10MnNb hot deformed austenite were studied and compared with 16Mn steel to determine the effect of niobium. The addition of niobium can delay the dynamic recovery and recrystallization of deformed austenite. Niobium steel dynamic recrystallization performance activation energy of 30.4kcal / mole, while the niobium steel was 74.9kcal / mole. The addition of niobium also significantly hindered the static recovery and recrystallization of hot-deformed austenite; the static recrystallization of the niobium-containing steel was almost completely suppressed at 800 ° C. Recrystallization of deformed austenite in two ways: one is strain-induced grain boundary migration, but not the main way, the main is through the original austenite grain boundary or annealed twin nucleation and growth. Strain-induced precipitation of carbides in deformed austenite and static precipitation of niobium carbide in un-deformed austenite indicate that a strain of 0.357 accelerates the precipitation of carbides by two orders of magnitude. The recrystallization process changes the size and distribution of the precipitated particles. This is due to rapid recrystallization of the precipitated particles caused by recrystallization of the front interface. In this paper, the microscopic mechanism of the interaction between recrystallization and precipitation is discussed. The reason Niobium inhibits the recrystallization process is due to the drag effect of the solute atoms on the grain boundaries or the subgrain boundaries and the pinning effect of the Niobium carbide precipitated particles on these grain boundaries. According to the rule of niobium on recrystallization and precipitation of hot deformed austenite, the control rolling process parameters of 10MnNb preferred steel were analyzed and suggestions were put forward.