Section 15 Base metals and articles of base metal 73 Articles of iron or steel 73 06 Other tubes, pipes and hollow profiles of iron or steel, welded, nes 73 06 30 Tubes and pipes, welded, circular, of iron or non-alloy steel, nes Commodity Code Description 73 06 30 00 Other, welded, of circular cross-section, of iron or non-alloy steel : 73 06 30 11 With an external diameter less than 12.5 mm 73 06 30 19 Other 73 06 30 21 With an external diameter less than 12.5 mm 73 06 30 29 Other 73 06 30 30 Pipe of a kind used to make sheath pipe (heater pipe) for heating elements of electri 73 06 30 40 High-pressure pipe capable of withstanding a pressure of not less than 42,000 psi : 73 06 30 41 High-pressure pipe capable of withstanding a pressure of not less than 42,000 psi : 73 06 30 49 Other 73 06 30 91 With an internal diameter of 12.5 mm or more, an external diameter less than 140 mm a 73 06 30 92 With an external diameter less than 12.5 mm 73 06 30 99 Other