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.