Production Process and Properties of DP800 Dual Phase Steel

The composition system,cooling treatment process,microstructure and performance of 800 MPa dual phase steel have been studied,and the effects of annealing temperature and cooling rate on the properties have been investigated.The strengthening mechanism of dual phase steel was analyzed,and the annealing process parameters were optimized. Results show that smelting process using C-Si-Mn-Cr-V component system,rolling process using 650 ℃ ± 20 ℃ in the temperature coiling,microstructure and mechanical properties can be qualified with cooling rate of 42~50 ℃/s and high content hydrogen H₂ of 20%,and cold-rolled dual-phase steels DP800 composed of ferrite and martensite can be obtained,and the comprehensive mechanical properties are excellent.