There are two types of square steel tube: welded and seamless .And price for seamless square tube is commonly higher than that of welded type. Welded square tube is made of steel plates or steel coils. Seamless square tube is made of round tubes, which always gives the finished products high mechanical prosperities.Product Feature1 Square Tube:Dimension: 20mm*20mm-600mm*600mm 2 Rectangular Tube:Dimension: 20mm*30mm-600mm*1000mm 3 W.T:2mm-35mm 4 Length:6m-12m , or as per customer's requirements 5 Standards:JISG 3466, EN 10210, EN10219, ASTM A500, GBT 3094-2000, GBT 6728-2002 6 Materials:Q195, Q235, Q345, 20#, 16Mn, ST3744ST52, ASTM A53106, STKR490STKR400, ASTM A500, S355, S275, S235 7 Technique: Welded & Seamless 8 Packing:Standard seaworthy packing or as requiredProduct SpecificationModelsRectangular comes in different sizes, specifications and wall thicknesses. Its uniformity makes it predictable to use and visually appealing. It has a high weight-to-strength ratio. Compared to round steel pipe, square steel tube is more efficient, stronger and durableApplicationConstruction structure, machinery making, container, hall structure, offshore oil field, sea trestle, motorcar cassis, airport structure, shipbuilding, automobile axle pipe, MRT and so on.Other InformationOur supply of stainless steel square tube and rectangular tube offerings are available in a wide variety of sizes and wall thicknesses. They are supplied in both mill finish and polished finishes, with the polished finishes including #4, #6 and #8 mirror finish. They are generally supplied in 20' random lengths but can be cut to size for orders. Available Steel Grades: 304, 304L and 316L We will custom saw cut to length and sell less than full lengths in some sizes. Mill finish and polished products in stock. Polishing services are available