... .3 percent, more than twice of cast iron products. Hot-dip galvanized treatment: Good rust-proof property, maintenance-free ... 4" etc.3Cross bar pitch38,50,76,100,101.6mm4MaterialQ235,A36,SS3045Surface treatmentBlack, hot dipped galvanising, paint6StandardChina: YB/T 4001.1 ... /NAAMM(MBG531-88)UK: BS4592-1987Australia: AS1657-1985 23)HOT SELL!hot dipped galvanized steel grating manufacturer (10 years )