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Stainless Steel Brush Finish Specifications
What constitutes a No. 4 brush finish on stainless steel? What is the min/max roughness for a No. 4 finish? Where can I find more info on No.3, No.4, No.6, and No. 8 finish specs?Joseph Litza
- Chicago, Illinois
No. 4 finish is typical 150-180 grit (satin) finish. Much like the stainless steel shutter found on 3.5" floppy diskette. No. 3 finish varies with the mill/polishers can be as low as 60 and as high as 140 grit. Roughness average (Ra) value is very dependent on the mills/polishers. The flatness of the coils/sheets, as they are handled and produced from the mills is a major decisive factors in the final Ra value.
No. 8 finish is a true mirror finish. No residual polishing lines should be found on the surface of the stainless. Roughness average (Ra) is 1 microinch or below.
I believe the Specialty Steel Industry of North America has free handbooks on the finishes of stainless steel sheets.
Also, ASTM should have finish specifications as well for a fee.
specialty stainless steel distributor
I have a part print that requires a #3 brush finish. Material is 380 Al. The only surface finish standard I have is an Ra reference. I do have a profilometer, but not sure what Ra or Rz value will roughly equal a #3 brush finish. Any help would be greatly appreciated.
- Clearwater, Florida
September 15, 2008
I have a component machined with aluminium material. I have to callout in drawing its surface finish symbol. Can any one help me in this issue.Kumar Pavan
- New York, USA
August 2, 2011 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread
What is the conversion of brushed #2 stainless steel surface finish equivalent?Matthew DuVall
Quality Specialist - Bloomington, Minnesota