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RA30 Finish on 304L SS

I am trying to find out what a RA30 finish is on 304L stainless steel. Does this equate to some RMS measurement or number brush finish?

Lisa McCole
engineering and manufacturing - Souderton, Pennsylvania, USA

Hi Lisa!

The best answer is "not exactly". Ra, or Roughness Average, is measured in a different way than is the Root Mean Square average. You want to surf on over to www.predev.com/smg/parameters.htm and read the explanation of the different surface finish parameters.

Have fun!

Lee Gearhart
metallurgist - E. Aurora, New York

RA is roughness average. It differs from RMS ( route means square ) in that the former measures the mean average to the peaks of the surface profile; whereas, the RMS is the measurement of both the peaks and valleys. To get an RA, double the RMs, or in this case divide by 2.

AF Kenton
retired business owner - Hatboro, Pennsylvania

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