Thank you both for the swift replies.
I need to develop a process where I have been give a maximum value of Rz. Also for economical reasons I will target a one stage peening process (i.e. one size shot)
I have carried out trials in the last couple of days using S170 and S230 and will be trialling S330 within the next week.
Jack, your answer confirms some of my theoretical thinking that a larger peen size will lead to a lower Rz. Extending the peening time slightly shouldn't be an issue.
There is a lot of research out there on Intensity and Coverage but very little on Surface Roughness control.
Hopefully I'll have the results I need by the end of next week.
Many thanks for your help and guidance.
