Lv Zhiqing, Qian Lihua, Liu Shuai, Zhan Le, Qin Siji
Key Laboratory of Advanced Forging & Stamping Technology and Science, Ministry of Education of China Yanshan University, Qinhuangdao 066004, China.
State Key Laboratory of Metastable Material Science and Technology, Yanshan University, Qinhuangdao 066004, China.
Materials (Basel). 2020 Jan 18;13(2):459. doi: 10.3390/ma13020459.
The low-carbon steel (~0.12 wt%) with complete martensite structure, obtained by quenching, was cold rolled to get the high-strength steel sheets. Then, the mechanical properties of the sheets were measured at different angles to the rolling direction, and the microstructural evolution of low-carbon martensite with cold rolling reduction was observed. The results show that the hardness and the strength gradually increase with increasing rolling reduction, while the elongation and impact toughness obviously decrease. The strength of the sheets with the same rolling reduction are different at the angles of 0°, 45°, and 90° to the rolling direction. The tensile strength (elongation) along the rolling direction is higher than that in the other two directions, but the differences between them are not obvious. When the aging was performed at a low temperature, the strength of the initial martensite and deformed martensite increased with increasing aging time during the early stages of aging, followed by a gradual decrease with further aging. However, the elongation increases with increasing aging time. The change of hardness is consistent with that of strength for the cold-rolled martensite, while the hardness of the initial martensite decreases gradually with increasing aging time.
通过淬火获得具有完全马氏体组织的低碳钢（约0.12 wt%），然后对其进行冷轧以得到高强度钢板。接着，在与轧制方向不同角度下测量钢板的力学性能，并观察低碳马氏体随冷轧压下量的微观组织演变。结果表明，硬度和强度随压下量增加而逐渐增加，而伸长率和冲击韧性明显降低。在与轧制方向成0°、45°和90°角时，相同压下量的钢板强度不同。沿轧制方向的抗拉强度（伸长率）高于其他两个方向，但它们之间的差异不明显。当在低温下时效时，初始马氏体和变形马氏体的强度在时效初期随时效时间增加而增加，随后随着进一步时效逐渐降低。然而，伸长率随时效时间增加而增加。冷轧马氏体的硬度变化与强度变化一致，而初始马氏体的硬度随时效时间增加逐渐降低。
