... service, ISO9001 Company, MS.Spring +8613512873247Hot dip galvanized steel grating, bar grating, stair treads, trench cover , tank grating ... of steel gratings, they are Plain Style Steel Grating, Serrated Style Steel Grating and I Bar Type Steel Grating. ... etc 4Material GradeASTM A36, A1011, A569, Q235, S275JR, SS304, Mild steel & Low carbon steel, etc5Surface TreatmentBlack, self colour, hot dip ...