Copper-tin base alloys (bronze)

74.03 - Refined copper and copper alloys, unwrought. - Refined copper : 7403.1 1 - - Cathodes and sections of cathodes 7403.13 - - Billets 7403.19 - - Other - Copper alloys : 7403.21 - - Copper-zinc base alloys (brass) 7403.22 - - Copper-tin base alloys (bronze) 7403.29 - - Other copper alloys (other than master alloys of heading 74.05) F This heading covers unwrou t refined copper and copper alloys as defmed in Chapter Notes 1 (a) and 1 @) respective y. Refined copper containing at least 99.85 % b weight of copper is obtained by electrolytic refining, electrolytic extraction, chemical re lning or fire refining. Other refined copper (containing at least 97.5 % by weight of copper) is normally produced by alloying the above-mentioned refined copper wth one or more other elements up to the maximum content limits as shown in the table m Chapter Note 1 (a). P Refined cop er is cast into ingots or in ot-bars for remelting (e.g., for alloying purposes) or into wire-bars, s abs for rolling, billets (inc uding those of circular cross-section) and similar forms for rolling, extruding, drawing or forging into plates, sheets, strip, wire, tubes and other products. P f Electrolytically refined copper is sometimes presented in the form of cathodes consisting of plates or sheets with two loops attached by which the original starting sheets were suspended in the electrolytic refining tank, or with the laops cut off, or cut into sections. Refined copper ma also be in the form of shot main1 used for alloying purposes and sometimes for grin mg into powder. Copper powders an flakes are, however, classified in heading 74.06. d: B This heading further covers cast and sintered slabs, bars, rods and ingots, etc., provided they have not been worked after production otherwise than by simple trimming or de-scaling (to remove the set or top surface consisting largely of cuprous oxide) or by shaving, chipping, grinding, etc., to e!imnate setting or other casting defects or which have been mach~nedon one surface for inspection purposes (quality control). Sintered products are obtained from cop er powder or copper alloy powders or from copper powder mixed with other metal owders, y pressing (corn acting and sintering (heating to an appropriate temperature below &e fusion point of the meta s) In t e sintered state the products are porous and of low strength and are normally rolled, extruded, forged, etc., to achieve useful density. These rolled, etc., products are excluded (e.g., headings 74.07,74.09). \ f'. h The headin also includes wire-bars and billets with their ends tapered or otherwise worked simply to acilitate their entry into machines for converting them into, for example, wire drawing stock (wire-rod) or tubes. f Subject to the above-mentioned conditions concerning working after production, the cast bars and rods of this heading may include, in particular : (1) Products (sometimes known as "jets '7, accurately cast in s ecial moulds, of round, square or hexagonal section and usually not exceeding 1 m in lengt . f: (2) Longer products obtained by the continuous casting*process in which molten metal is poured continuously into a water-cooled mould where it is rapidly solidified. Both the "jets " and the contimously cast bars are offen used for the same purposes as rolled, drawn or extruded bars.