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Ted Mooney, P.E. RET
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Size loss of up to .001" during passivation of stainless steel
Q. I am Jimmy McClure a grinder of O D and I D of aerospace company. We run stainless steel parts at high limit on O D And low limit on I D And after being sent out for passivation the same parts are coming back with O D under sized and I D of same part over size by as much as .001"
Jimmy Mcclure- Madble North Carolina
November 8, 2019
Ed. note: This RFQ is outdated, but technical replies are welcome, and readers are encouraged to post their own RFQs. But no public commercial suggestions please ( huh? why?).
A. Hi Jimmy. You are a grinder, so can we assume these parts receive no heat treatment (which could result in scaling and then scale removal) after your efforts, but only passivation?
Passivation should have negligible effect on the dimensions. However, it has been known to etch components if operated incorrectly for the grade of stainless steel in question, and some are relatively easy or relatively hard to passivate. To solve the problem you probably will need to determine the grade of stainless steel, the specification that they are being passivated to, and what type of passivation (citric acid , nitric acid, nitric acid plus chromic acid)
Regards,
Ted Mooney, P.E. RET
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