Section 15 Base metals and articles of base metal 81 Other base metals; cements; articles thereof 81 09 Zirconium and articles thereof, including waste and scrap 81 09 91 -- Containing less than 1 part hafnium to 500 parts zirconium by weight Commodity Code Description 81 09 91 00 -- Containing less than 1 part hafnium to 500 parts zirconium by weight