ALUMINUM BASE PLATED STEEL SHEET FOR FUEL TANK HAVING EXCELLENT CORROSION RESISTANCE AND CHROMIUM ELUTION RESISTANCE

摘要

PROBLEM TO BE SOLVED: To provide an aluminum base plated steel sheet which obviates the elution of hexavalent Cr and is adequate as material for a fuel tank having excellent durability. SOLUTION: This aluminum base plated steel sheet for the fuel tank is constituted by forming an Al-Si alloy plating layer of 5 to 13 mass % Si via an Al-Fe-Si base intermediate layer on the surface of the steel sheet and forming a phosphoric acid-chromium-aluminum composite film consisting essentially of CrPO4 and AePO4 at a Cr coating weight of 5 to 60 mg/m2 on the Al-Si alloy plating layer. The phosphate-chromium-aluminum composite film preferably contains P and Cr at a mass ratio of P/Cr=1.0 to 2.5.