Pickling and passivation can be done for SS 410 steel. I have done it in past for one of my fabricated jobs as it was client requirement.
Passivation treatments are done for removal of free iron and other contamination resulting from handling, fabrication, or exposure to contaminated atmospheres, and pickling treatments for removal of high temperature scale from heat treatment or welding operations.
Passivation Treatments:
Grades with at least 16% chromium (except free machining grade such as 303), 20-50% nitric acid, at room temperature to 40oC for 30-60 minutes.
Grades with less than 16% chromium (except free machining grades such as 416), 20-50% nitric acid, at room temperature to 40oC for 60 minutes.
Free machining grades such as 303, 416 and 430F, 20-50% nitric acid + 2-6% sodium dichromate, at room temperature to 50oC for 25-40 minutes.
Pickling Treatments:
All stainless steels (except free machining grades), 8-11% sulphuric acid, at 65 to 80oC for 5-45 minutes.
Grades with at least 16% chromium (except free machining grades), 15-25% nitric acid + 1-8% hydrofluoric acid, at 20 to 60oC for 5-30 minutes.
Free machining grades and grades with less than 16% chromium such as 303, 410 and 416, 10-15% nitric acid + 0.5-1.5% hydrofluoric acid, at 20 to 60oC for 5-30 minutes.
"Pickling Paste" is also available and is a commercial product of hydrofluoric and nitric acids in a thickener - this is useful for pickling welds and spot contamination, even on vertical and overhanging surfaces.
Hence please proceed with pickling and passivation but carefully..
Regards
Prem Nautiyal
On Fri, 23 Apr 2010 22:28:56 +0530 wrote
>Dear All,
I am working as a static equipment engineer for refinery&petrochemical projects.
As per Owner requirements All SS tray assemblies to be pickled & passivated.
Howeever the tray vendor claims it is not applicable for SS410S as pickling & passivation may lead to white & brown pathches on trays.
Please clarify if pickling & passivation for SS410S (martensitic grade) materials is applicable or not?
Awaiting your prompt response.
Yours
Salman Hussain,Baroda,India.
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PREM S NAUTIYAL
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