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Inline anneling and Bright anneling 1

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amtechal

Automotive
Joined
Jul 21, 2009
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3
Location
US
Where is the best place to do the anneling, Is it before the sizing or after?
 
Before the sizing of what? More details will equal more meaningful responses.
 
Sorry is it best to place the induction coil before the sizing end of a tube mill or at the exit end of a tube mill?
 
well that depends. typically it is done after weld bead working but before sizing. Since sizing is less than 0.5% it doesn't impart much work. By the same token it does have to be after the weld bead cold working since this should; be about 5% cold reduction of the weld bead.
The other comment of to decide if this is actually an anneal. I have seen much stainless tubing recently that was not solution annealed (non-uniform grain size and odd distribution of carbides) coming off of inline systems. It meets the mechanical properties so they call it good. It wouldn't pass corrosion tests.
And don't be fooled by the phrase "inline bright anneal", the inside surface is not bright annealed. The ID only sees an inert gas so there is measurable (even if invisible) oxidation on the ID that greatly reduces the corrosion resistance. This is 'wing and a prayer' tubing.

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Plymouth Tube
 
Thanks and are you stating that you cant inline bright anneal?
 
I have never seen it done. The OD surface is bright annealed, but the ID isn't.
This is very common today in commodity tubing. If 304 is all that you need then it is probably fine.
If you get inline bright annealed 316 don't expect it's corrosion resistance to anything like what is in the books on corrosion. It can't come close.

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Plymouth Tube
 
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