PARTIAL-ISOTHERMALLY-TREATED LOW ALLOY ULTRAHIGH STRENGTH STEEL WITH MARTENSITIC/BAINITIC MICROSTRUCTURE
We introduce a new strengthening heat treatment of a Ni-Cr-Mo-V alloyed spring steel by partial isothermal salt-bath and subsequent air-cooling and tempering.Detailed isothermal treatments were made at temperatures below or above the Ms point(230℃).The salt bath time was controlled between 10 and 80 minutes.Through the new treatment,the candidate steel developed ultrahigh tensile strength~2,100 MPa,yield strength~1,800 MPa,elongation 8-10%,hardness 580-710 HV,and V-notch Charpy toughness 10-12 J.Optical and electron microscopic observations and X-ray diffraction revealed multi-phase microstructures of bainitic/martensitic ferrites,fine carbide precipitates and retained austenite.Carbon partitioning during the bainitic/martensitic transformation was investigated for its remarkable influence on the strengthening mechanism.
Ultra-High Strength Steels Multi-Phase Microstructure Isothermal Heat Treatment X-Ray Diffraction Scanning Electron Microscopy
Quanshun Luo Matthew Kitchen Vinay Patel Martin Filleul Dave Owens
Materials and Engineering Research Institute,Sheffield Hallam University,Howard Street,Sheffield,S1 Tinsley Bridge Limited,335 Shepcote Lane,Sheffield,S9 1TG,United Kingdom
国内会议
杭州
英文
433-438
2015-11-11（万方平台首次上网日期，不代表论文的发表时间）