Galling while continuous annealing 304SS
Galling while continuous annealing 304SS
(OP)
We are continuous annealing 304 SS tubing between drawing passes to thin the tubing wall. We get galling of the outer surface of the tubing as it moves through and contacts the muffle tube in the annealing furnace. The furnace is about 2000F. We use disassociated ammonia for the atmosphere. What causes the galling of the 304 tubing? How can it be prevented?





RE: Galling while continuous annealing 304SS
RE: Galling while continuous annealing 304SS
RE: Galling while continuous annealing 304SS
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Plymouth Tube
RE: Galling while continuous annealing 304SS
The muffle tubes are 4 inches ID and 10 ft long. They are made of RA330, an austenitic alloy.
Depending on the wall thickness of the 304SS tubing we're processing, speed through the annealing oven varies from 24 fpm to 55 fpm @ 2000F. If 2000F is too hot, then what is the upper limit to prevent galling?
As the tubing moves through the muffle it undulates or becomes 'snake-like', so it's touching the ID of the muffle tubes in several places. Supporting it somehow to avoid tubing-to-muffle contact looks impossible.
I appreciate the help.
RE: Galling while continuous annealing 304SS
If the tubes are snaking then I suspect a combination of crooked tubes going in and uneven heating. Try attacking those two issues.
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Plymouth Tube
RE: Galling while continuous annealing 304SS
RAYBAND
Rock Island Arsenal
AMSTA-RIA-SEM