Fe-0.2C-11Mn-(2,4,6)Al钢在热冲压过程中回弹行为的研究

Research on springback behavior of Fe-0.2C-11Mn-(2,4,6)Al steel during hot stamping

本文以Fe-0.2C-11Mn-(2,4,6)Al钢为研究对象,从合金成分和热冲压工艺参数两个角度出发,来研究中锰钢板在热冲压成形过程中的回弹问题.通过高温拉伸实验和微观组织扫描,结合测量冲压件回弹角所得规律分析可得,铁素体可提升塑性,加剧回弹现象;马氏体含量增多会导致材料塑性下降,但会减轻回弹;晶粒尺寸增大会降低屈服强度,降低弹性模量,从而减小回弹角.所以在相同冲压条件下,随着Al含量的增高,马氏体减少,铁素体增加,塑性增强,冲压件的回弹角逐渐增大.通过高温拉伸力学性能分析,发现随着保温温度的升高,峰值强度、屈服强度降低,伸长率升高,各钢种冲压成形件的回弹角逐渐减小.故在本实验中,2Al的回弹角最小.

The spring-back behavior affected by composition and hot stamping parameters of Fe-0.2C-11Mn-(2,4,6)Al medium-Mn steel was investigated in this study.Through high temperature tensile test and microstructure observation,combined with the variation of spring-back angle,it was indicated that ferrite can improve plasticity,but reduce spring-back.In contrast,increase in martensite content will deteriorate ductility,but reduce the spring-back angle.Moreover,increase in grain size will decrease the yield strength and the elastic modulus,with consequence decrease in spring-back angle.Therefore,under the same stamping conditions,the spring-back angles of the stamping experimental steels were gradually increased with increase in Al content,due to the increase in martensite content,the reduce in ferrite content.According to the results of high temperature tensile test,the peak strength and the yield strength decrease with increase in holding temperature,while the elongation increases with increase in holding temperature,leading to the decrease in spring-back angle.In conclusion,the spring-back angle of 2Al steel is the smallest.