Abstract
The effects of Cr, Mo and Ni additions on the microstructure and stretch-flangeability of 0.2%C-1.5%Si-1.5%Mn-0.05%Nb, in mass%,TRIP-aided martensitic sheet steel produced by isothermal transformation process at a temperature below martensite-finish temperatures were investigated to develop the 3rd-generation sheet steel for automobile requiring high hardenability. When 0.5% or 1.0% Cr was added to the base steel, the combination of tensile strength of 1.5 GPa and hole-expanding ratio of 40% was attained. On the other hand, the Cr-Mo or Cr-Mo-Ni addition hardly influenced the stretch-flangeability and stretch-formability, although it increased the yield and tensile strengths, comparing to the base steel. The good balance of Cr-bearing steel was mainly caused by suitable combination of (1) volume fraction and (2) interparticle path of finely dispersed martensite-austenite complex phase (M-A phase), which suppressed a void initiation at the matrix/M-A phase interface on hole-punching and void coalescence or crack extension on hole-expanding.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
