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Etch solution for 15-5 Stainless
Q. I am currently trying to get good etch on 15-5 stainless. I am using a solution of 22% v/v nitric acid and 2.2% hydrofluoric acid at room temperature. What I see with sample coupons is the material starts to etch a little and then stops. Whether I leave the piece in the solution for 5 mins or 30 mins, nothing seems to come off the part. I need to take at least .0002-.0004 off for the job I'm trying to run and I am having trouble achieving that. I have looked at the ASM handbook and Graham's handbook but I couldn't seem to find an etch solution for my particular material. Does anyone have an etch solution recipe that can achieve this? Preferably one I could run at ambient temperature?
Thanks in advance.
- Oxnard, California, USA
August 7, 2012
A. You may need to increase fluoride concentration a bit, say to 5%. Ammonium bifluoride is safer to use than Hydrofluoric acid.
At ambient temperature I'm guessing that you'll then remove .0002" or more in 30 minutes.
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Jeffrey Holmes, CEF
Spartanburg, South Carolina
August 8, 2012
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