half tempered?
- Thread starter Henny
- Start date
Sponsored Links
Half-hard temper in yellow metals – brass copper etc. refers to the heat treatment during manufacture – in the case of copper tube the extruded tube is cooled then heated then cooled rapidly (annealing) to produce a finished product that is relatively tough but malleable enough to be bent using suitable formers such as springs or bending machines. – BS2871 Table X and Y Table X is for indoor use; plumbing, heating etc. Table Y is thicker wall and is for below ground use and high pressure installations. Just to really confuse things Table Y is also available in condition ‘O’ or soft with the same wall thickness but lower pressure rating; this is generally used for radiant heating panels where resistance to expansion stresses is important.
Hard drawn tube is not annealed and so cannot be bent without risk of cracking, it should not be used underground either because of the risk of damage during compaction. – BS 2871 Table Z
Soft, full temper or condition ‘O’ tube (double annealed) is very easily bent and is usually supplied in coils – mini and microbore BS2871 table W
All of these are made from phosphorous deoxidised copper (as opposed to arsenic deoxidised, which is generally not good for anything these days).
Hope this tells you what you need to know.
Hard drawn tube is not annealed and so cannot be bent without risk of cracking, it should not be used underground either because of the risk of damage during compaction. – BS 2871 Table Z
Soft, full temper or condition ‘O’ tube (double annealed) is very easily bent and is usually supplied in coils – mini and microbore BS2871 table W
All of these are made from phosphorous deoxidised copper (as opposed to arsenic deoxidised, which is generally not good for anything these days).
Hope this tells you what you need to know.
very informative pth 
Indeed - just one small point: it doesn't matter how quickly you cool an "element" like copper (or aluminium) , (as opposed to an alloy like steel, brass...), it won't affect the hardness. Common misconception.
It DOES matter how hot it got and for how long. The metal has to recrystallize to get the stresses out, which were making it hard.
Lead is a bit special cos it recrystallizes well at room temperature, which is why you can bash it about and it doesn't "work harden" (much!).
It DOES matter how hot it got and for how long. The metal has to recrystallize to get the stresses out, which were making it hard.
Lead is a bit special cos it recrystallizes well at room temperature, which is why you can bash it about and it doesn't "work harden" (much!).
Sponsored Links
ChrisR - Yes, thanks for that: the reason that commercially produced tube is quenched as opposed to being left to cool is that 'lengths' are stored in bundles and 'coils' are, well, coiled. So from the heat treatment plant the the stock would cool quickly on the ends of the lengths and the outside of the coils which induces distortion. Not many people want to buy wibbly-wobbly tube!
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
