steel tube standards ASTM, API, DIN, EN, BS, JIS, UL, usage:structure, liquid transfering,sprinkler syetem.frame,fence tube steel tubeincluding ERW and Seamless, round ... : 16mm-508mm, Wall thickness:1mm---20mm. PURPOSE: fluid tube, fence tube, structural tube, scaffolding tube, water transferring tube, oil pipe, casing pipe, sprinkler fire fighting system ...