Standard: GB, DIN, ASTM, API Standard: GB 5310-1995, GB/T 8163-1999, GB/T 8162-1999, DIN 1629/4, DIN 2448, ASTM A106-2006, ASTM A53-2007, ASTM A335-2006, API 5CT, API 5L Grade: 10#-45#, 16Mn, A53-A369...