... GradeASTM A36, A1011, A569, Q235, S275JR, SS304, Mild steel & Low carbon steel, etc5Surface TreatmentBlack, self colour, hot dip galvanized, painted, spray ... : AS1657-1985, Japan:JIS 2)Application:platform, flooring walkway,steel structures, stair tread, well cover, trench cover, sump cover,compound gratings ... water plant, defense project, chemical factory and so on. galvanized steel stair treads