ASTM A786/A786M is the standard specification for hot-rolled floor plates
Section 12 of the PDF is gold. It provides a clear table for flatness deviations under a straightedge. For a 4’x8’ plate, the allowable bow is surprisingly tight (approx. 1/4” over 8 feet). I’ve rejected entire truckloads of plate that looked like potato chips because the mill didn’t follow Table 2 of A786. Having this PDF on hand during a receiving inspection gives you legal leverage. astm a786 pdf