round tube,are lf various shapes $ specifications.round,square,rectangle,mpaistic,bizarre,screwy,etc. 1) Sizes: OD(mm) ... , nitrogen protection 7) Standard: Q/GBS1-2005, ASTM A225 8) Polishing: 80#, 180#, 240#, 320#, 400#, more than 400# 9) Application ...