主要对0.19C-1.52Si-1.53Mn-0.14Al-0.048Nb和0.19C-1.52Si-1.48Mn-0.15Al两种成分的钢进行了Q&P(quenching and partitioning)工艺处理,并研究二次淬火对Q&P钢组织性能的影响.结果表明:Nb的加入能够起到细晶强化和沉淀强化的效果,提高Q&P钢的综合性能.强塑积最高可达到25 190 MPa.%.二次淬火能够提高实验钢最终的马氏体含量,并大大提高钢的抗拉强度和屈服强度,降低了实验钢的应变硬化指数和总延伸率.若不采用二次淬火则会使实验钢的塑性大大提高,综合力学性能较高.
The mechanical property and forming limit experiments were carried out on a high manganese TRIP/TWIP steels with manganese of 18.8%.And the forming limit diagram was obtained.This high manganese steel shows outstanding mechanical properties combining high strength with good formability.Its limit plane strain corresponding to the lowest point in the plain strain condition is about 38%.The effects of conventional mechanical property on the limit plane strain were analyzed.With increasing the content of Mn,the limit plane strain increases,indicating that TWIP effect is advantageous to the increase of formability.Combining with three classical models and volume invariable principle,a FLD model was built,which is suitable for high manganese steels very well.
The static recrystallization behaviors in SCM435 steel were investigated by two-pass hot compression tests on MMS-200 thermosimulation machine. Effects of deformation temperature, strain rate,deformation degree and the initial austenite grain size on static softening were analyzed. The stress compensation method was used to calculate the static recrystallization. The kinetics model of the static recrystallization of SCM435 steel was established and the obtained activation energy for static recrystallization was 182. 8 kJ /mol. Results showed that within a certain time interval( 1-100 s),the static recrystallization fraction X of SCM435 steel increased as the deformation temperature,the deformation rate and the amount of deformation increased,and it decreased as the initial grain size increased and increased as the time interval increased.
