... , windows, curtain walls, highway, windows of model steel door, building materials, fence, etc Square steel pipe/Hollow steel section1) Thinkness: 1.0--20mm2) OD: 15 ... G 3466Material:Q195, Q215, Q235, Q345, Fe310, Fe360, St33, St37-2, ASTM 1010, ASTM 1017, ASTM 1020Surface:Painted, oiled,galvanized square steel pipe Stainless square steel pipe