Rustproof steel sheet excellent in various characteristics including corrosion resistance

摘要

A Zn-Cr plated steel sheet which is excellent in corrosion resistance and has a phase structure containing heretofore unknown phases eta x, delta x and tau x. The following characteristics (1) to (6) are exhibited by one or a combination of these phases: (1) eta x resistance to surface rusting; (2) tau x moldability; (3) eta x + delta x chipping resistance; (4) eta x + tau x corrosion resistance after working; (5) delta x + tau x secondary adhesion in warm water; (6) eta x + delta x + tau x resistance to pitting corrosion, eta x: hexagonal, a = 2.66 APPROX 2.74 ANGSTROM , c = 4.61 APPROX 4.95 ANGSTROM , delta x: hexagonal, a = 2.72 APPROX 2.78 ANGSTROM , c = 4.43 APPROX 4.60 ANGSTROM , tau x: cubic, a = 3.00 APPROX 3.06 ANGSTROM .