Zn—Al—Mg plated checkered steel plate

A Zn—Al—Mg alloy coated checkered steel sheet, comprising:

• a substrate checkered steel sheet having a convex part and a flat part on one sheet surface;
• and
• a coating layer including a Zn—Al—Mg alloy layer disposed on the sheet surface of the substrate checkered steel sheet having the convex part and the flat part,
• wherein the coating layer has a chemical composition containing, in % by mass:
• Zn:
• greater than 65.0%,
• Al:
• from greater than 1.0% to less than 25.0%,
• Mg:
• from greater than 1.0% to less than 12.5%,
• Sn:
• from 0% to 5.0%,
• Bi:
• from 0% to less than 5.0%,
• In:
• from 0% to less than 2.0%,
• Ca:
• from 0% to 3.00%,
• Y:
• from 0% to 0.5%,
• La:
• from 0% to less than 0.5%,
• Ce:
• from 0% to less than 0.5%,
• Si:
• from 0% to less than 2.5%,
• Cr:
• from 0% to less than 0.25%,
• Ti:
• from 0% to less than 0.25%,
• Zr:
• from 0% to less than 0.25%,
• Mo:
• from 0% to less than 0.25%,
• W:
• from 0% to less than 0.25%,
• Ag:
• from 0% to less than 0.25%,
• P:
• from 0% to less than 0.25%,
• Ni:
• from 0% to less than 0.25%,
• Co:
• from 0% to less than 0.25%,
• V:
• from 0% to less than 0.25%,
• Nb:
• from 0% to less than 0.25%,
• Cu:
• from 0% to less than 0.25%,
• Mn:
• from 0% to less than 0.25%,
• Li:
• from 0% to less than 0.25%,
• Na:
• from 0% to less than 0.25%,
• K:
• from 0% to less than 0.25%,
• Fe:
• from 0% to 5.0%,
• Sr:
• from 0% to less than 0.5%,
• Sb:
• from 0% to less than 0.5%,
• Pb:
• from 0% to less than 0.5%,
• B:
• from 0% to less than 0.5%, and
• impurities,
• wherein, when observing a cross section of cutting edge orthogonal to a longitudinal direction of the convex part and taken along a sheet thickness direction at a central part in the longitudinal direction of the convex part, a layer thickness ratio of the coating layer of the flat part on left and right sides of the convex part (layer thickness of left coating layer/layer thickness of right coating layer) is from 0.2 to 5.0, and
• wherein a convex height T-t, where T is a sheet thickness of the substrate checkered steel sheet at the convex part and t is a sheet thickness of the substrate checkered steel sheet at the flat part, and a gap height x between a stationary surface and a sheet surface of the coated checkered steel sheet opposing the stationary surface in a case in which the coated checkered steel sheet is placed in a stationary position, satisfy the following Formulae 1 and 2 below:
• x/(T−t)≤1.5 Formula 1:
• 0.5<T−t≤t Formula 2:
• wherein, in Formula 1 and Formula 2, units of the sheet thickness T, t, and the gap height x of the substrate checkered steel sheet are millimeters.