Quenching partitioning tempering （QP-T） process were applied to a quenched carbide-free bainite/mar- tensite （CFB/M） multiphase steel 40Mn2Si2Cr and its effect on the mechanical properties was studied. The results...Quenching partitioning tempering （QP-T） process were applied to a quenched carbide-free bainite/mar- tensite （CFB/M） multiphase steel 40Mn2Si2Cr and its effect on the mechanical properties was studied. The results showed that the partitioning time of Q P T treatment can he increased greatly to 90 min or even longer. The tensile strength, elongation and product of strength and elongation （PSE） of the experimental steel can achieve 1650 MPa, about 20% and over 33 GPa ·%, respectively. The significant increase of partitioning time and excellent mechanical properties could be related to the CFB microstrueture introduced in the quenching process during the Q-P-T treat- ment.展开更多
The austempering above and below martensite transition temperature(M_(s))was employed in a medium-carbon low-alloy 40CrNiMo steel,and the bainite and martensite multiphase microstructures with different volume fractio...The austempering above and below martensite transition temperature(M_(s))was employed in a medium-carbon low-alloy 40CrNiMo steel,and the bainite and martensite multiphase microstructures with different volume fractions were obtained.Here,the effect of pre-existing martensite on subsequent transformation of bainite microstructure and mechanical properties is focused and researched.The microstructure with a volume fraction of pre-existing martensite(V_(PM)),bainite(V_(B)),and martensite/austenite(V_(M/A))constituents of approximately 28%,46%,and 26%,respectively could be obtained by austenitizing below M_(s)(280℃)for 1 h,and an optimum combination of strength,ductility,and impact toughness(yield strength of 1420 MPa,ultimate tensile strength of 1795 MPa,total elongation of 7.9%,and V-notch impact value of 37 J)was achieved.The considerable enhancement of mechanical properties in the sample austenitized below M_(s)is mainly ascribed to the formation of the pre-existing martensite,resulting in an effective reduction in the size of the bainite plates and martensite/austenite constituents.展开更多
基金Item Sponsored by National Natural Science Foundation of China(51271013)Key Project of Chinese Ministry of Railways(2012G011-C)Central College Basic Scientific Research Business Expenses Special Funds of China(2011JBZ021)
文摘Quenching partitioning tempering （QP-T） process were applied to a quenched carbide-free bainite/mar- tensite （CFB/M） multiphase steel 40Mn2Si2Cr and its effect on the mechanical properties was studied. The results showed that the partitioning time of Q P T treatment can he increased greatly to 90 min or even longer. The tensile strength, elongation and product of strength and elongation （PSE） of the experimental steel can achieve 1650 MPa, about 20% and over 33 GPa ·%, respectively. The significant increase of partitioning time and excellent mechanical properties could be related to the CFB microstrueture introduced in the quenching process during the Q-P-T treat- ment.
基金support of the Natural Science Foundation of Shanxi Province,China(Nos.201901D111105,201901D111114).
文摘The austempering above and below martensite transition temperature(M_(s))was employed in a medium-carbon low-alloy 40CrNiMo steel,and the bainite and martensite multiphase microstructures with different volume fractions were obtained.Here,the effect of pre-existing martensite on subsequent transformation of bainite microstructure and mechanical properties is focused and researched.The microstructure with a volume fraction of pre-existing martensite(V_(PM)),bainite(V_(B)),and martensite/austenite(V_(M/A))constituents of approximately 28%,46%,and 26%,respectively could be obtained by austenitizing below M_(s)(280℃)for 1 h,and an optimum combination of strength,ductility,and impact toughness(yield strength of 1420 MPa,ultimate tensile strength of 1795 MPa,total elongation of 7.9%,and V-notch impact value of 37 J)was achieved.The considerable enhancement of mechanical properties in the sample austenitized below M_(s)is mainly ascribed to the formation of the pre-existing martensite,resulting in an effective reduction in the size of the bainite plates and martensite/austenite constituents.
