Looking for shop test to separate mixed oxygen free non oxygen free copper

not an expert, but if you go to fig 3 of

http://www.copper.org/publications/newsletters/innovations/1997/12/wiremetallurgy.html

you can set up a pass/fail electrical conductivity test. If you can get your measurement error to less than 0.5% and measure electrical conductivity more than 102% IACS, then you can be sure you have the right stuff. Obviously, if you are dealing with wire stock (you did't specify), you can cut pretty accurate test samples provided you use enough length.

With plate/ bar stock, it'll take much effort to cut accurate-size and smooth enough test pieces and you probably won't be able to achieve reliable accuracy. I've never heard of an expedient shop test for oxygen-free copper, here we've always had to trust the suppliers and ask for certificates of conformity; I fear you may have to resort to spectrometry after all, perhaps by external lab (1 check=less than 200euro if I recall correctly...)

hope this helps

Hi Milo,

Just a short knowledge, at all an expert but there are some different "oxygen free" copper specifications. Most of them are used as electrical conductors, but they can have substantial variations on electric conductivity. As you can see in the previous post, any impurity use to lower the conductivity value, not just oxygen, so the combined effect can confuse if just measure the conductivity.

The main oxygen free copper specifications are:

• C10100 - 99,9 % Cu (Oxygen free electronic copper) Minimum 101% IACS
• C10200 - 99,95 % Cu (Oxygen free copper) Minimum 101 % IACS
• C10300 - 99,95 % Cu, 0,003 %P (Oxygen free, extra low phosphorous copper) Minimum 99% IACS
• C10400/10500/10700 - (Oxygen free, silver bearing copper) 99,95%Cu + 250/310/780 ppm Ag respectively. Minimum 100% IACS
• C10800 - 99.95% Cu. 0,009% P (Oxygen free, low phosphorous copper) Minimum 92% IACS.

So you see that obviously if you measure 102% IACS you can be sure that is an oxygen free copper grade, but not the contrary.

Why is it needed "oxygen free" grade? Because electrical conductivity? Then you only need test it and be sure it complies with your minimum requirement.

If the intended use is other (mechanical), oxygen makes the copper more prone to hydrogen embrittlement and oxygen bearing coppers use to fail the ASTM B170 bending test. (It's not an easy test.. you need before bending, hold the sample in a pure hydrogen atmosphere 30 minutes @ 850ºC/ 1560ºF).

Kind regards

Its simple really, DO NOT BUY IT FROM CHINA. Anyone else will try to meet your specs. They will try to screw you.

Thanks all.

It is bar stock.

Not certain of country of origin, Have no seen my clients certs.

Material is cracking, in fabrication, and we suspect material was misapplied.

Appreciate your suggestions.

milo