square steel tube standards ASTM, DIN, EN, BS, JIS, UL, galvanized, painted rectangular, square certificate: ... square steel tube, rectangular or square, according to standards ASTM A53, ASTM A106, ASTM A795, ASTM A135, ASTM A500, EN10219, EN10255, EN10240, EN39(BS1139), DIN2440/DIN2444 ...