qualité commerciale

CONT: Les différentes qualités commerciales de cuivre se distinguent essentiellement par leurs teneurs résiduelles en oxygène et en phosphore (...)
OBS: Le cuivre et les alliages de cuivre font l'objet des normes ISO du domaine 140 groupe 3080.

CONT: Commercial grades of copper. The purest commercial grades are electrolytic and low resistivity lake copper, both of which are more than 99.9 per cent pure.... A grade of copper known as fire refined other than lake ... is used for rolling into sheets.... A third grade, arsenical or high resistance lake copper, may contain as much as 0.50 per cent of arsenic.... About twenty grades of copper are furnished for special uses....