HDG steel pipe 1. many different sizes of the products ... under the ISO:9001-2000 strictly1) Standard:API 5L,ASTM 36.10M,A106,A53,DIN 1629,1626,BS,JIS ... .etc2) Material: ASTM A106/A53,ST37,35, API 5L GR. B / ... SSAW,7) Surface treatment:bare,black painting,anti rust oil,hot dipped galvanized,3pe,etc8) Length: 5.8 ... ,shipbuilding,boiler,construction,,metallurgy,etc HDG steel pipe