Abstract: An aluminium-zinc-hot-dipped and colour-coated steel plate having yield strength of ?500 MPa and a high elongation and a manufacturing method thereof, with the chemical components in mass percentage of a substrate of the steel plate being: 0.07-0.15% of C, 0.02-0.5% of Si, 1.3-1.8% of Mn, N?0.004%, S?0.01%, Ti?0.15%, Nb?0.050%, and the balance being Fe and other inevitable impurities, and meanwhile satisfying the conditions of: (C+Mn/6)?0.3%; Mn/S?150; Nb satisfying 0.01%?(Nb-0.22C-1.1N)?0.05% where no Ti is contained; Ti satisfying 0.5?Ti/C?1.5 where no Nb is contained; and 0.04%?(Ti+Nb)?0.2% where Ti and Nb are added in combination. The steel plate has a tensile strength of ?550 MPa, an elongation after fracture of ?15%, a good strength and toughness and an excellent corrosion resistance.

Abstract: An aluminium-zinc-hot-dipped and colour-coated steel plate having a 500 MPa yield strength grade and a high elongation and a manufacturing method thereof, with the chemical components in mass percentage of a substrate of the steel plate being: 0.07-0.15% of C, 0.02-0.5% of Si, 1.3-1.8% of Mn, N?0.004%, S?0.01%, Ti?0.15%, Nb?0.050%, and the balance being Fe and other inevitable impurities, and meanwhile satisfying the conditions of: (C+Mn/6)?0.3%; Mn/S?150; Nb satisfying 0.01%?(Nb-0.22C-1.1N)?0.05% where no Ti is contained; Ti satisfying 0.5?Ti/C?1.5 where no Nb is contained; and 0.04%?(Ti+Nb)?0.2% where Ti and Nb are added in combination. The steel plate has a yield strength of ?500 MPa, a tensile strength of ?550 MPa, an elongation after fracture of ?15%, a good strength and toughness and an excellent corrosion resistance.