1)Made of mild steel or Q235 2)HDG with powder coating 4)Octagonal, round ... coating. We owned advanced production-line, it included Flatting machine, Steel plate shearer, bending machine, Auto-closed up machine, submerged arc ... ; Octagonal tapered; Straight square; Tubular stepped; Shafts are made of steel sheet that folded into required shape and welded longitudinally by ...