Dear members,
I am searching for information about surface roughnesses as a result of shotpeening with different sizes. I cannot find any generic article on that subject. Of course there are a lot of specific articles which mentions roughnesses due to shotpeening, but then mostly for one or two specific cases with a few size or intensities. When e.g. using the search words “roughness shot size” I get 18 articles, but they are all very specific.
Most interesting would be an excel file, where one could correlate surface rougnesses (Ra and/or Rt) from different kind of metals with shotsize and intensities.
Just as examples (values are not true:

Metal:.....Shotsize:...Intensity:....Roughness:
Ti6Al4V........S110......6 - 10A.....120 - 160 mi
Ti6Al4V....... S230......6 - 10A.....100 - 140 mi
Steel<200ksi.. S110..... 6 - 10A..... ?
Steel>200ksi.. S110...... etc. etc..

Anybody information ?
Or maybe an idea to collect those data from members so a big excel information file can be made.

Kind regards
Marcel

Marcel,
The surface roughness of peened components varies not only with shot size, component hardness and peening intensity but also with initial component roughness and coverage. A comprehensive study of surface roughness would therefore be an enormous undertaking. Surface roughness is, however, directly related to indent depth. Equations do exist that allow indent depth to be predicted - knowing shot diameter, density, velocity and component hardness.

As an example, Marcel sent us a graphic with roughness results for gritblasting with aluminium-oxide grit and different mesh sizes. Marcel says "of course this is a very general one and can only be used as an reference for e.g. steel surfaces. But you understand the general idea. In this case air-pressure, spray distance and angle of attack is all together a distinguishing number."

Click here to view the pdf.

The graphic is fascinating but raises a number of questions: (1) All of the curves appear to converge on an origin that corresponds to zero roughness. Does that mean that the un-blasted samples were optically-flat? (2) How is the "distinguishing number" calculated?