These tubes are then subjected to various processes like Pickling, Passivation, Hydro Testing, Polishing, Inspection, Marking before packing and dispatch. GradesAustenitic Grade: TP-304, 304L, 304H, 316, 316L, 316H, 316Ti, 317, 321, 347, 310, 904L, Ferritic Duplex Grades: UNS S32750, S32760, S31803, S31500, 32205