奥氏体化温度对TRIP钢连续冷却过程中组织转变的影响
Effect of austenitizing temperature on structural transformation of TRIP steel in the continuous cooling
陈闪闪,赵爱民,李振,张宇光,唐荻
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作者单位:北京科技大学冶金工程研究院
中文关键字:TRIP钢;CCT图;微观组织;激发形核;相变
英文关键字:TRIP steel;CCT diagram;microstructure;excitation nucleation;phase transition
中文摘要:采用热膨胀实验测定实验钢三种不同奥氏体化温度下的CCT曲线,针对CCT曲线图中铁素体和贝氏体相变区域的变化,通过光学显微镜和扫描电镜观察奥氏体化温度对试样室温下显微组织的影响。结果表明:奥氏体化温度越低,晶粒越细小;随着奥氏体化温度的降低,铁素体和贝氏体相变受激发形核作用的影响其相变区间逐步扩大并左移;珠光体相变和马氏体相变驱动力只受合金元素在初始奥氏体内富集程度的影响,其开始转变点温度随奥氏体化温度的降低而降低。
英文摘要:The continuous cooling transformation (CCT) curves of experimental steel were determined by thermal expansion tests in three different austenitizing temperatures. In view of the changes of the ferrite and bainite phase transition region, optical microscope and scan electron microstructure (SEM) were used to observe the effect of austenitizing temperatures on the microstructure of samples at room-temperature. The result shows that the lower the austenitizing temperature, the more fine grain. With the austenitizing temperature decreasing, the ferrite and bainite transformation were affected by excitation nucleation, which resulted that the phase transition range was gradually expanded and the curves were shifted to the left. The driving force of the pearlite and martensite transformation was only affected by the enrichment of the alloying elements in the initial austenite. The pearlite and martensite starting points were gradually decreasing with the austenitizing temperature decreasing.