Resource Library

I have been offered electrical grade copper tube CW004A (C101) instead of CW024A (C106). Is this acceptable?

Yes, the mechanical properties are identical. Take care if you braze the tubes, use an oxidising flame.

What does EPNS stand for?

Electroplated nickel silver.

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?

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.

Metals in British Coins

Infographic produced by Compound Interest – www.compoundchem – showing metal content of all British coins.

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Which brass would you recommend for fittings for tubes which have to resist dezincification?

CW707R (CZ 126).

What does grain size mean and why is it important for copper?

Copper, like other metals, is made up of millions of tiny grains. In the case of copper that 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.

I have some brass components which have stained on machining. How can I clean them?

Use an acidic dip such as a mixture of citric and phosphoric acids. This is quite gentle and with care easy to use.

What does the term DEF STAN (DStan) mean?

These are the engineering standards prepared for material for use by the Ministry of Defence.  They have replaced NES (Naval Engineering Standards), which in their turn replaced DGS (Directorate General Ships) standards.

Which copper alloy has a good electrical conductivity and retains strength up to 400°C?

Copper chromium (CC101) – conductivity is 80% IACS – strength good up to 400°C.

I intend to use copper as a cladding material but I do not want to wait for the natural patina to form. What do you suggest that I might use?

Copper sheet is available in pre-patinated form.  As well as green, other attractive colours such as brown, gold and silver are available.  See www.kme.com and www.aurubis.co.uk.

What effect does heavy cold working have on the electrical conductivity of copper?

It reduces by about 3%.