Dou Cunchao, Sun Zhendong, Shen Depeng, Guo Ning, Liu Zhe, Cheng Lin, Liu Yongchao, Tang Bingtao
School of Mechanical Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China.
Shandong Machinery Design & Research Institute, Jinan 250031, China.
Materials (Basel). 2024 Jun 3;17(11):2715. doi: 10.3390/ma17112715.
The Laasraoui segmented and Arrhenius flow stress model, dynamic recrystallization (DRX) model, grain size prediction model, and hot processing map (HPM) of Fe-Cr-Mo-Mn steels were established through isothermal compression tests. The models and HPM were proven by experiment to be highly accurate. As the deformation temperature decreased or the strain rate increased, the flow stress increased and the grain size of the Fe-Cr-Mo-Mn steel decreased, while the volume fraction of DRX () decreased. The optimal range of the hot processing was determined to be 1050-1200 °C/0.369-1 s. Zigzag-like grain boundaries (GBs) and intergranular cracks were found in the unstable region, in which the disordered martensitic structure was observed. The orderly packet martensite was formed in the general processing region, and the mixed structure with incomplete DRX grains was composed of coarse and fine grains. The microstructure in the optimum processing region was composed of DRX grains and the multistage martensite. The validity of the Laasraoui segmented flow stress model, DRX model, grain size prediction model, and HPM was verified by upsetting tests.
通过等温压缩试验建立了Fe-Cr-Mo-Mn钢的拉斯劳伊分段和阿累尼乌斯流变应力模型、动态再结晶（DRX）模型、晶粒尺寸预测模型和热加工图（HPM）。经实验验证，这些模型和HPM具有很高的准确性。随着变形温度降低或应变速率增加，Fe-Cr-Mo-Mn钢的流变应力增加，晶粒尺寸减小，而DRX的体积分数（）降低。确定热加工的最佳范围为1050-1200℃/0.369-1s。在不稳定区域发现了锯齿状晶界（GBs）和沿晶裂纹，其中观察到无序马氏体组织。在一般加工区域形成了有序的块状马氏体，由粗晶粒和细晶粒组成具有不完全DRX晶粒的混合组织。最佳加工区域的微观组织由DRX晶粒和多级马氏体组成。通过镦粗试验验证了拉斯劳伊分段流变应力模型、DRX模型、晶粒尺寸预测模型和HPM的有效性。
