Oxygen Free Athmosphere for Annealing

Dear moderator and members,

Would you please to share your knowledge and experiences on copper wire continuous annealing process?

I am concerned about the most effective medium/fluid that can be used to purge Oxygen at the annealing process (continuous annealing) for copper wire. What is the purpose to prevent oxidation on copper wire.

Recently we use steam to purge (to wipe away) Oxygen at the annealing process. But we have no guide about standard pressure and flow-rate for that steam.

Please share your experience on this matter.

We also think about what is better (a medium/fluid perhaps) than steam in this oxygen purging matter. In one of discussion in this forum, I read that another type of medium/fluid that able to purge oxygen away is Nitrogen.

Please share your experience about N2 usage. Is it better than steam?

In my thoughts, nitrogen may be better than steam because of its easy ability to cool down annealed wire.

If we use steam as oxygen purging medium, because steam is high temperature fluid, will it will prevent annealed wire from cooling down?

Please share your comments and experiences.

Thank you very much.

Regards,
Siampudan

Hello Siampudan,

As you know, a steam tube is formed around the hot conductor during annealing and this, in my experience, is completely adequate to keep oxygen at bay.

You must however be sure to keep the cooling section operating properly so that the copper conductor is cool when it exits the water column.

If your system is designed for steam, I recommend that you fully inspect it an repair any problems found.

Kindest Regards,
Peter Stewart-Hay
Principal
Stewart-Hay Associates
www.Stewart-Hay.com

Dear Mr. Stewart-Hay,

Thank you for your advice and information.
I have a further question, if you don't mind.

Please inform me if you have data about what is the optimum steam flow-rate and pressure needs for annealing process. May be you have such kind of correlation table among steam pressure (and flow-rate) vs copper wire diameter and its speed (meter per minute or mpm).
Recently, we have no guidance for that matter. And some times we found copper wire discolor (reddish) defect easily due to higher temperature of copper wire comes out of annealing section. It was predicted that this problem happened due to an excessive usage of steam (because there is no guidance for its usage) and cooling insufficient after annealing process

For: All of wire.net member,

Do you have information about nitrogen usage as controlling atmosphere ( to purge Oxygen)on copper wire annealing? I want to now its effectiveness compare to steam usage.

Best regards,

Siampudan

Hello again,

In my understanding the water cooling section is connected to the annealing section so that the wire is cooled before entering the normal atmosphere. This is what prevents discoloration or oxidation you have described.

If the steam in the annealing section if supplied by some external source, or the steam tube in the water if created by the hot wire itself, there is only one purpose for that steam and that is to keep any oxygen away from the hot wire. This would also be the case if you used nitrogen instead of steam.

The water level in the cooling section must balance the steam or nitrogen pressure and the flow upwards of the water itself by virtue of being dragged along by the moving wire so that the wire is sufficiently cooled to prevent oxidation. The more water the better, within reason of course. Cooling section inlet and outlet water seals augment the water pressure. You are therefore creating a water pressure balance.

Unfortunately I do not have access to data to steam or nitrogen flow rates for your particular annealer but there should be water level sight glasses, etc. on your annealer to guide you on how to set up the water cooling portion of your annealer.

The easiest way to compare cost of steam to nitrogen is to calculate the cost to boil "x' amount (volume) of saturated steam and compare that to the cost of purchasing an equivalent volume of nitrogen. If you need assistance with the steam calculation, any university trained mechanical engineer who studied thermodynamics can easily assist you with that issue.

Kindest Regards,
Peter Stewart-Hay
Principal
Stewart-Hay Associates
www.Stewart-Hay.com

What is the ultimate use of the wire. Are you going into an enamelling operation or are you spooling it for future use.

Thank you very much Vettecoupe for your valuable explanation.

For Spectre07, for large wire ( 1.0 mm to 2.6 mm)some of them went to our customer which is proceed with drawing process till fine wire and even super fine wire. some of fine wire goes to bunching process. Some of them go to enameling process (magnet wire application).
Please give me some comments regarding benefit of steam vs nitrogen usage on annealing.

regards,