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采用淬火膨胀仪测定了两种不同Cr含量(0.2%和0.5%)的贝氏体钢筋的连续冷却转变曲线(CCT曲线),并采用光学显微镜(OM)、扫描电镜(SEM)和维氏硬度分析了Cr元素对贝氏体钢筋过冷奥氏体连续冷却转变规律、显微组织特别是贝氏体组织转变规律以及显微硬度的影响。研究表明,Cr含量从0.2%提高至0.5%对贝氏体转变具有显著影响;同时,少量的Cr对贝氏体的形态及分布具有显著影响,当Cr含量为0.2%时,贝氏体形态以粒状贝氏体和上贝氏体板条为主,但是Cr提高至0.5%时,观察到了“柳叶状”的下贝氏体组织,因此添加少量的Cr即可显著提高贝氏体转变区间钢的显微硬度。
The continuous cooling transformation curves (CCT curves) of two kinds of bainitic steel with different Cr contents (0.2% and 0.5%) were measured by means of a quench dilatometer. The mechanical properties of the bainitic steel bars were studied by optical microscope (OM), scanning electron microscope The effects of Cr on the continuous cooling and transformation of undercooled austenite, the microstructure, especially the microstructure transformation and the microhardness of bainite were analyzed. The results show that increasing the Cr content from 0.2% to 0.5% has a significant effect on the bainite transformation. Meanwhile, a small amount of Cr has a significant effect on the morphology and distribution of bainite. When the Cr content is 0.2%, the bainite morphology With granular bainite and upper bainite slab, but the Cr increased to 0.5%, observed the “willow-like” lower bainite tissue, so adding a small amount of Cr can significantly improve the Bayesian Body change the hardness of the interval steel.