冷轧压下率和平整伸长率对低碳钢退火板组织性能的影响

Effects of cold rolling reduction rate and flat extension rate on microstructure and properties of annealed low carbon steel sheet

研究了冷轧压下率和平整伸长率对低碳钢退火板组织性能的影响。结果表明,在相同的退火工艺下,提高冷轧压下率能有效减小铁素体晶粒尺寸,晶粒的细化不仅提高了屈服强度和屈强比,而且还增大了屈服平台伸长率。通过Hall-Petch和Hollomon方程分别建立了试验钢屈服强度与晶粒尺寸,以及屈服平台伸长率与晶粒尺寸之间的定量关系。随着平整伸长率的提高,屈服强度先减小后增大,而抗拉强度变化不明显。采用1.5%平整伸长率不仅可以消除7.2%屈服平台,并能使试验钢保持最低的屈服强度和屈强比。

Effects of cold rolling reduction and flat extension rate on microstructure and mechanical properties of annealed low carbon steel were investigated. The results show that the ferrite grain size decreases effectively by cold rolling reduction and increases under the same continuous annealing process. With the decrease of grain size, not only the yield strength and yield ratio but aslo the elongation of yield plateau increases. A quantitative relationship between yield strength and grain size, elongation of yield plateau and grain size of the tested steel are established respectively by using Hall-Petch and Hollomon equations. Yield strength decreases first and then increases with flat extension rate rising, but tensile strength has no obvious change. 1, 5% fiat extension rate not only eliminates 7.2% elongation of yield plateau, but aslo keeps minimal yield strength and yield ratio of the tested steel.