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研究了 Si-Mn-Cr-Mo 系列热轧双相钢从室温到-180℃,三种不同应变速率下的低温性能和断裂特征。结果发现此钢具有良好的低温延性。在三种应变速率下,随实验温度的降低,在断裂强度和屈服强度增加的同时延伸率基本保持不变。在相同试验温度下,断裂强度与应变速率无关,而高应变速率使屈服强度有所增加,使延伸率稍有降低。用 SEM 和 TEM 对各种样品断口和位错组态观察表明:此钢的冷脆转变温度在-100—-140℃之间,并且随实验温度的降低,马氏体的位错组态发生了相应的变化。微观结构的变化反映了材料的加工硬化能力,并且与宏观力学性能的变化相对应。
The low temperature properties and fracture characteristics of Si-Mn-Cr-Mo hot-rolled dual-phase steel at room temperature to -180 ℃ and three different strain rates were studied. The results show that this steel has good low temperature ductility. At the three strain rates, with the decrease of the experimental temperature, the elongation remains basically unchanged while the breaking strength and yield strength increase. At the same test temperature, the breaking strength is independent of the strain rate, whereas the high strain rate increases the yield strength and slightly decreases the elongation. SEM and TEM observations of the fracture and dislocation configurations of various samples show that the cold-brittle transition temperature of this steel is between -100 and -140 ° C and the dislocation configuration of the martensite occurs as the experimental temperature decreases The corresponding changes. The changes of the microstructure reflect the work hardening ability of the material, and correspond to the changes of macroscopic mechanical properties.