Goods of common metal, namely metal rings, tubes, pipes, ducts of metal, elbows for pipes, feeding pieces, breeches pipes, T-pieces, connection pieces, pipe junctions, pipe flanges, adapter pieces, threaded pipes, clips for pipes, pipe muffs, nuts, shell coupling pieces, tie plates, valves and fittings (other than parts of machines); parts of the aforementioned goods of metal; reinforcing materials of metal for pressure pipes