【摘要】 利用微合金析出物与临界晶粒尺寸的定量关系,研究了Si含量较高的中碳Nb微合金钢在不同加热温度下的奥氏体晶粒长大规律。结果表明,随着加热温度的升高,试验钢中奥氏体晶粒逐渐长大,当温度高于1100℃时,晶粒开始粗化。由经验模型可得,随着温度的升高,析出相的体积分数逐渐减少,而颗粒半径逐渐增大,由于二者的共同作用导致了奥氏体晶粒在高于1100℃时迅速粗化;在实验的基础上,得到了适用于试验钢的晶粒长大模型。更多还原

【Abstract】 Based on the relationship between microalloying precipitates and critical grain size,the grain growth behavior of a Nb microalloyed medium carbon steel containg high silicon was studied at different elevated temperatures.It is found the austenite grain size of the tested steel gradually increases with temperature increasing and high rate grain coarsening occurs when heating temperature above 1100℃.The high rate grain coarsening is attributed to the decreasing of the volume fraction of precipitates and its coarsening as well when heating temperature higher than 1100℃.A grain growth model concerning the effects of the volume fraction and size of precipitate is proposed for the tested steel.更多还原