... .ISO9001 Steel grating specification: Specifications of steel gratingsNoItemDescription1Bearing bar20x5, 25x3, 25x4, 25x5, 30x3, 30x4, 30x5, 32x3, 32x5, 40x5, 50…75x8mm, etc.2Bearing bar pitch25 ... ), I bar (I section)7Material standard Low carbon steel (CN: Q235, US: A36, UK: 43A)8Galvanization standardCN: GB/T13912, US: ASTM (A123), UK: BS7299Steel grating ...