Chapter 74

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Copper and articles thereof

NOTE :

In this Chapter, the following expressions have the meanings hereby assigned to them:

(a) Refined copper

Metal containing at least 99.85 per cent. by weight of copper; or

Metal containing at least 97.5 per cent. by weight of copper, provided that the content by weight of any other element does not exceed the limit specified in the following Table :

TABLE - OTHER ELEMENTS

* Other elements are, for example, Al, Be, Co, Fe, Mn, Ni, Si.

(b) Copper alloys

Metallic substances other than unrefined copper in which copper predominates by weight over each of the other elements, provided that :

(i) the content by weight of at least one of the other elements is greater than the limit specified in the foregoing table; or

(ii) the total content by weight of such other elements exceeds 2.5 per cent.

(c) Master alloys

Alloys containing with other elements more than 10 per cent by  weight, of copper not usefully malleable and commonly used as an additive in the manufacture of other alloys or as de-oxidants, de-sulphuring agents or for similar uses in the metallurgy of non-ferrous metals. However, copper phosphide (phosphor copper) containing more than 15% by weight of phosphorous falls in heading 2853

SUB-HEADING NOTE :

In this Chapter the following expressions have the meanings hereby assigned to them:

(a) Copper-zinc base alloys (brasses)

Alloys of copper and zinc, with or without other elements. When other elements are present:

(i) zinc predominates by weight over each of such other elements;

(ii) any nickel content by weight is less than 5%. [see copper-nickel-zinc alloys (nickel silvers)]; and

(iii) any tin content by weight is less than 3%. [see copper-tin alloys (bronzes)].

(b) Copper-tin base alloys (bronzes)

Alloys of copper and tin, with or without other elements. When other elements are present, tin predominates by weight over each of such other elements, except that when the tin content is 3% or more the zinc content by weight may exceed that of tin but must be less than 10%.

(c) Copper-nickel-zinc base alloys (nickel silvers)

Alloys of copper, nickel and zinc, with or without other elements. The nickel content is 5% or more by weight [see copper-zinc alloys (brasses)].

(d) Copper-nickel base alloys

Alloys of copper and nickel, with or without other elements but in any case containing by weight not more than 1% of zinc. When other elements are present, nickel predominates by weight over each of such other elements.