Section 15 Base metals and articles of base metal 73 Articles of iron or steel 73 03 Tubes, pipes and hollow profiles, of cast iron 73 03 00 Tubes, pipes and hollow profiles, of cast iron. 73 03 00 00 Tubes, pipes and hollow profiles, of cast iron. Commodity Code Description 73 03 00 00 000 Tubes, pipes and hollow profiles, of cast iron.