Effects of TMCP Parameters on Microstructure and Mechanical Properties of Hot Rolled Economical Dual Phase Steel in CSP

Effects of chemical compositions, finish rolling temperature, isothermal temperature on runout table and coiling temperature on microstructure and mechanical properties of economical dual phase steel produced on CSP line were investigated. Experimental results showed that martensite volume fraction could be enhanced and banding microstructure could be reduced by controlling Mn, Si contents and applying proper finish rolling temperature. Optimized processing-parameters were obtained for DP580 production on CSP line of Wuhan Iron and Steel (group) Co (WISCO) in China. Optimal microstructure and mechanical properties could be achieved when the strip was finished rolling at the range of 790 to 830 ℃, isothermally holding at 680 to 740 ℃ and coiling below 250 ℃.