500 MPA YIELD STRENGTH GRADE HIGH STRETCHABILITY HOT DIP ALUMINUM ZINC AND COLOR COATED STEEL PLATE AND MANUFACTURING METHOD THEREFOR

摘要

A 500 MPa yield strength grade high stretchability hop dip aluminum zinc and color coated steel plate and a manufacturing method therefor. The percentage by mass of a substrate of the steel plate is chemically: C: 0.07% 0.15% Si: 0.02% 0.15% Mn: 1.3% 1.8% S ??? 0.01% N ??? 0.004% Ti ??? 0.15% Nb ??? 0.050% and the remainder being Fe and unavoidable impurities and at the same time satisfies: (C + Mn/6) ??? 0.3%; when Ti is absent Nb satisfies 0.01% ??? (Nb 0.22C 1.1N) ??? 0.05%; when Nb is absent Ti satisfies 0.5 ??? Ti/C ??? 1.5; and when a Ti Nb composite is added 0.04% ??? (Ti + Nb) ??? 0.2%. The steel plate has a yield strength ??? 500 MPa tensile strength ??? 550 MPa and stretchability ??? 15% and is provided with great strength and toughness and great corrosion resistance.