Electropolishing is warping my thin stainless parts
Electropolishing is warping my thin stainless parts
(OP)
I have some stainless parts that I am electropolishing, the parts are discs that are 0.2mm thick and 15mm in diameter. What I'm finding is that they are warping and I can't figure out what will stop them warping. I can't change the thickness which is very thin and I've reduced the current so much that they seem to take forever to finish - 4 hours! I'm removing about 0.05mm thickness all in and losing maybe the same in diamter, that is ok and what I want, it is just that I want them to stay flat. What is happening do you think? Any pointers?





RE: Electropolishing is warping my thin stainless parts
RE: Electropolishing is warping my thin stainless parts
I'm using very hard 17-7Ph that came in condiditon C and has been preciptation hardened.
Thanks, Ant.
RE: Electropolishing is warping my thin stainless parts
If so, can you terminate the periphery of the disc and electropolish both faces at once?
Separately from that:
The increased warping with higher current density suggests localized heating, possibly from random concentration gradients in the electrolyte.
Are you agitating or circulating the electrolyte?
Can you/ do you use a shaped cathode? E.g., a faced rod of the same diameter as the disc, located in close proximity to the disc?
Mike Halloran
Pembroke Pines, FL, USA
RE: Electropolishing is warping my thin stainless parts
RE: Electropolishing is warping my thin stainless parts
This will at least give you some natural convection.
A simple agitator would help, Just something to gently stir the solution.
Make sure that your connection to the part covers a large area, preferably all of the back.
Your cathode should match your part shape.
Uniformity is your friend.
I presume that this material is in the CH900 condition.
How much machining was done after aging?
It might be worth re-aging (at 885) part way through machining.
You may have way too much internal stress.
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Plymouth Tube
RE: Electropolishing is warping my thin stainless parts
I will use a disc instead of a rectangular sheet and ensure that the connection is much bigger, I think just the wire in one spot will be causing a problem.
The bath/tank i'm using is shaped to prevent bubbles sticking under the part and that does seem to work.
Thanks,
Ant.
RE: Electropolishing is warping my thin stainless parts
As long as you don't exceed the original temp you shouldn't change the strength, but staying just below it is a good precaution.
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Plymouth Tube