Iron or steel (excluding cast iron); tubes and pipes (e.g. welded, riveted or similarly closed), having circular cross-sections, external diameter of which exceeds 406.4mm, not seamless

730511 Iron or steel (excluding cast iron); line pipe of a kind used for oil or gas pipelines (not seamless), longitudinally submerged arc welded, having circular cross-sections, external diameter exceeds 406.4mm 730512 Iron or steel (excluding cast iron); line pipe of a kind used for oil or gas pipelines (not seamless), longitudinally welded (not submerged arc welded), having circular cross-sections, external diameter exceeds 406.4mm 730519 Iron or steel (excluding cast iron); line pipe of a kind used for oil or gas pipelines (not seamless), (not longitudinally welded), having circular cross-sections, external diameter exceeds 406.4mm 730520 Iron or steel (excluding cast iron); casing of a kind used in drilling for oil or gas (not seamless), having circular cross-sections, external diameter exceeds 406.4mm 730531 Iron or steel (excluding cast iron); tubes and pipes (other than line pipe or casing of a kind used for oil or gas pipelines), longitudinally welded, having circular cross-sections, external diameter exceeds 406.4mm, (not seamless) 730539 Iron or steel (excluding cast iron); tubes and pipes (other than line pipe or casing of a kind used for oil or gas pipelines), welded (not longitudinally welded), having circular cross-sections, external diameter exceeds 406.4mm, (not seamless) 730590 Iron or steel (excluding cast iron); tubes and pipes n.e.c. in heading no. 7305, having circular cross-sections, external diameter exceeds 406.4mm, (not seamless)