Section 15 Base metals and articles of base metal 73 Articles of iron or steel 73 05 Other circular tubes and pipes, diameter >406.4mm, of iron or steel 73 05 39 Iron/steel tubes and pipes, spirally welded, >406.4mm external diameter 73 05 39 00 Iron/steel tubes and pipes, spirally welded, >406.4mm external diameter Commodity Code Description 73 05 39 00 00 Iron/steel tubes and pipes, spirally welded, >406.4mm external diameter