Effect of isothermal quenching temperature on microstructure and properties of 51CrMnV spring steel
Effect of isothermal quenching temperature on microstructure and mechanical properties of 51 CrMnV spring steel was studied by means of optical microscope(OM),scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray diffraction(XRD),electron backscatter diffraction(EBSD)technique and electronic universal testing machine.The results show that after using high-temperature oil quenching medium for isothermal quenching treatment,the microstructure of the 51 CrMnV spring steel mainly consists of martensite,bainite ferrite,retained austenite and carbides.After austenitizing at 860 ℃ for 30 min and quenching in high-temperature oil at 280 ℃ for 30 min,the mechanical properties of the 51 CrMnV spring steel are good,with the tensile strength of 1641 MPa,the total elongation of 15.57％,and the reduction of area of 33％.The fracture surface of the tensile sample under this process condition is ductile fracture,which is attributed to the submicron bainitic ferrite and dispersed carbides in the experimental steel under this process condition.The synergistic effect of multiphase microstructure improves the comprehensive mechanical properties of the 51 CrMnV spring steel.
spring steelaustemperingbainiteretained austenitemechanical property
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