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研究了奥氏体化温度对调质Ti--V微合金钢力学性能的影响.金相和透射电镜观察揭示了奥氏体晶粒尺寸随奥氏体化温度的变化规律.在850~1200℃的温度范围内,随着奥氏体化温度的升高,奥氏体晶粒尺寸经历了稳定—骤增—稳定三个阶段.抗拉强度和冲击韧性试验结果显示,实验钢的抗拉强度R m随着奥氏体化温度的升高逐渐增加,而冲击韧性则经历了稳定—降低—升高的过程.一定温度下沉淀相粒子的粗化导致了奥氏体晶粒尺寸的突然增加;随温度升高,合金元素不断固溶所导致的回火后弥散析出的增多和沉淀相粒子的有效钉扎是抗拉强度增加的主要原因,而一定温度下晶粒的不正常长大和尺寸均匀化则是影响实验钢冲击韧性的关键因素.
The effect of austenitizing temperature on the mechanical properties of Ti-V microalloyed steels was studied.The microstructure and TEM observation revealed the variation of austenite grain size with the austenitizing temperature.Under 850 ~ 1200 ℃ , The austenite grain size undergoes three stages of stability-surge-stabilization as the austenitizing temperature increases.The results of tensile strength and impact toughness show that the tensile strength R m increases gradually with the increase of austenitizing temperature, while the impact toughness undergoes a steady-decrease-increase process.The coarsening of precipitated particles at a certain temperature leads to the abrupt increase of austenite grain size ; With increasing temperature, the alloy elements are caused by solid solution after tempering increased precipitation and precipitation phase particles effective pinning is the main reason for the increase in tensile strength, and a certain temperature of abnormal growth and grain size Homogenization is the key factor affecting the impact toughness of experimental steel.