Should soft annealing of Copper be done using regular air or in an inert atmosphere ?

[kedarg6500]

We use copper washer made from UNS C 111000.
The thickness of the washer is 0.029"-0.035" (0.737-0.889 mm). The hardness of RAW material is 63-65 HT (Rockwell 15 T scale). The requirement on drawing is to soft anneal the washer to tune of 25-35 HT (Rockwell 15 T scale).
Whether soft annealing can be done in regular air OR it is to be done in special inert atmosphere?

any help from members

 

[somashekar]

Re: soft annealing of Copper

We use copper washer made from UNS C 111000.
The thickness of the washer is 0.029"-0.035" (0.737-0.889 mm). The hardness of RAW material is 63-65 HT (Rockwell 15 T scale). The requirement on drawing is to soft anneal the washer to tune of 25-35 HT (Rockwell 15 T scale).
Whether soft annealing can be done in regular air OR it is to be done in special inert atmosphere?

any help from members

Can the attachment in THIS thread be of any use to you ... ?
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..
...

And if you are doing the soft annealing yourself, I found this as I was looking around.

How To Anneal Copper

The copper should be clean and bright, otherwise oxides will form and become embedded in the surface on heat-up, and should be warmed up with a blow-lamp (a kitchen stove will do this at a push) generally rather than at a specific point, although copper tends to spread heat quickly through the metal.

Once a background heat is produced, when the metal shows different colours radiating away from the heat source, then you are looking for a dark red (plum colour) reaching the part you want annealing – it’s like the colours of the rainbow moving from blue through to bright red as the hottest.

Once this occurs quickly immerse the copper you are annealing into a water bath, and that’s it. Job done.

The easy test is to tap it with a screwdriver or something similar. If you hear a ringing sound, the copper is still hard and needs to be annealed again. If the sound is dull then you have annealed the copper properly.

Don’t delay the quenching too much otherwise you will not achieve the annealed copper you were aiming for.

Before you begin to work the copper you must remove any surface oxides that have formed with a wire brush, wire wool or emery cloth as these become embedded, spoiling the appearance, and are difficult to remove later.

 

[harry]

Re: Should soft annealing of Copper be done using regular air or in an inert atmosphe

We anneal drawn copper wire by allowing it to cool slowly in air. No oxidation had ever been observed, so I think cooling in inert atmosphere isn't necessary.

For a better understanding of the physics and chemistry of the process, read

Annealing (metallurgy)