304 vs 201 Brushed Finish
304 vs 201 Brushed Finish
(OP)
I have seen some posts about a concern for brushed finishes on 201 stainless steel. Does anybody have experience with using a brushed finish with 201 vs 304 stainless steel. Our Salt Fog testing shows that 201 is not as good.





RE: 304 vs 201 Brushed Finish
Do they have the same S content?
At neutral pH they should behave exactly the same, they have the same Cr content.
In more aggressive environments 304 will slightly out perform 201.
It probably relates to surface finish, cleanliness,inclusions, and passivation.
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RE: 304 vs 201 Brushed Finish
RE: 304 vs 201 Brushed Finish
= = = = = = = = = = = = = = = = = = = =
Rust never sleeps
Neither should your protection
http://www.trent-tube.com/contact/Tech_Assist.cfm
RE: 304 vs 201 Brushed Finish
This behavior suggests oxide inclusions [not removed by nitric acid passivation] along the rolling direction, perhaps due to inadequate pickling prior to rolling. Try brushing pickling paste (alumina/nitric/HF) along the row of defects, rinsing & re-passivating.
But, even if successful, the material will have a pitted surface which could cause future problems. Suggest
1) buying from a supplier with better quality,
2) using a finer grained surface (the smoother the better w.r.t. corrosion resistance), e.g., a #4 finish before brushing, and
3) requiring salt spray testing for qualification of material.