600 MPa grade multiphase steel with good flanging performance and production method thereof

The invention relates to a 600 MPa grade multiphase steel with good flanging performance, and the 600 MPa grade multiphase steel with the good flanging performance comprises the compositions of, by weight, 0.060-0.100% of C, 0.060-0.400% of Si, 1.20-2.00% of Mn, 0.020% or less of P, 0.010% or less of S, 0.015-0.070% of Als, 0.15-0.35% of Cr, 0.010-0.035% of Ti, 0.010-0.035% of Nb and 0.006% or less of N; A production process comprises the steps that according to the composition setting, blank casting is conducted after conventional smelting is conducted; hot rolling process is performed; coldrolling process is performed; the blank casting is naturally cooled to room temperature, and the blank casting is waiting for used. Yield strength is 360 - 440 MPa, tensile strength is 600 ~ 700 MPa,elongation is 19% or above, the hole expansion rate is 45% or above. The microstructure of the 600 MPa grade multiphase steel is pearlite, bainite, ferrite, a small amount of martensite and residual austenite, thus it is ensured that the good forming performance, flanging performance and collision energy absorption performance are achieved while the high strength is achieved.