1. Unit of ¡Ó478 spiral-seam HF welded steel pipes possesses specifications from ¡Ó194 to ¡Ó478 and carries out standard SY/T5038-92
2. Unit of ¡Ó820 spiral-seam arc-in welded steel pipes has specifications from ¡Ó219 to ¡Ó820 and carries out standard SY/T5037-92