... column is made by a steel pipe with diameter of 114 mm, wall thickness of 2.2 mm, quality and technical ... 2.2 mm-thick cold-roll steel sheet, with bores of 6 mm in diameter. Conforming to the ... 3. Iron part:The iron part is made of a steel pipe with diameter of 60 mm, 48mm, 38mm, 32mm, 28mm, ... wall thickness of 2.5 mm, quality and technical standard of ...