变形速率对普碳钢中形变诱导铁素体相变的影响

针对普通碳素钢(Q235类型)，研究在Ae3～Ar3温度区间内采用形变诱导铁素体机制获得超细晶铁素体的数量与变形速率的相互关系。实验在Gleeble 1500热模拟实验机上进行。实验方案为：1000℃保温2min，以10℃／s的速度冷却到变形温度Ae3(840℃)至Ar3(780℃)]，变形量为30％～50％，变形后立即水淬。结果表明，在840℃变形时，随着变形速率的增大，形变诱导铁素体量增多；在780℃变形时，随着变形速率的增大，形变诱导铁素体量减少；而在840-780℃之间变形时，变形速率存在最佳值，在该值下诱导生成的铁素体量最大。

Effect of Strain Rate on Deformation Induced Ferrite Transformation in Plain Low Carbon Steel

The relationship between volume fraction of ultra-fine grained ferrite and strain rate was investigated for a plain low carbon steel (type Q235). The ultra-fine grained ferrite was obtained by Deformation Induced Ferrite Transformation (DIFT) in the deformation temperature range of A(e3)-A(r3). The experiments were carried out on a hot deformation simulator (Gleeble 1500). The austenization temperature of specimens was 1 000 , 2 min and followed cooling at 10 /s to deformation temperature. The deformation temperature range of A(e3) (840 )-A(r3) (780 ) and the reduction range of 30%-50% were adopted. The results indicated that with the strain rate increasing, the volume fraction of ferrite increased at 840 while decreased at 780 ; there was an optimum strain rate within the temperature range of 840-780 , and under this deformation condition maximum volume fraction of ferrite would be induced.