Q Do copper and copper alloys become brittle at low temperatures?
A No.
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Q What is the melting point of copper?
A 1083°C
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Q Which copper alloys are strongest?
A Copper-beryllium alloys.
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Q Can copper and copper alloys be hardened by heat treatment?
A Some alloys can, including copper-beryllium, copper-chromium and copper-nickel-silicon. Most unalloyed coppers and brasses can only be softened by heating.
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Q High conductivity is needed in electrical equipment running at high temperatures. What grade of copper should be used?
A Copper with silver added or copper-chromium.
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Q What is temper as applied to copper and copper alloys?
A Strength and hardness increases with the percentage of cold reduction after hot working. Properties are defined in standards. See also CDA publications.
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Q What does grain size mean, why is it important for copper?
A Copper like other metals is made up of millions of tiny grains. In the case of copper which is to be worked these range in size from 0.01 to 0.1mm. The grain size is particularly important where copper is to be fabricated by cold working - generally the smallest grain size that can be economically fabricated into a desired component is used.
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Q What is the solution treatment temperature?
A This term applies to alloys such as Cu-Be and Cu-Cr which are strengthened by age (precipitation hardening). It is the temperature (900-1000C) to which the alloys are heated prior to quenching and ageing.
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Q Where can I learn about the metallurgy of copper alloys including the phase diagrams and heat treatment?
A Phase diagrams are in Pub 94. Other details are in Pubs 122 and 117. For more info, contact CDA.
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Q I have produced some brackets in a fully heat treated Cu-Be alloy C112 which I am unable to bend. Can I soften them sufficiently by annealing?
A No, it is recommended that they are solution treated at 850-920°C, then bent to shape and finally aged at 420 to 470°C.
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