I am wondering how many operators rotate parts of varying diameters at a constant surface speed to help reduce the number of saturation graphs they need to produce for each sized part, or if they have a part that requires peening from a small diameter out to a large diameter get on with the rate at which the part is covered, as the surface speed on a larger diameter part is greater than on a smaller diameter part. I would assume that the feed rate of the nozzle would have to reduce or part rotation speed slow down as the nozzle moves out.

We currently use 75mm per second as our starting point because of the flow rates and machinery we currently have.
We started at this because the guys used to do Almen strips by hand @ 1 second per pass. With automation and increased flow rates I believe you could easily double if not triple this rate.
Let me know how you go.

75mm per second converts to 4.5m per minute surface speed(Vc) (75x60=4500mm/sec)

To work out the RPM of a part.

RPM= (Vc X 1000)/(pi x DIA)

Where
Vc is velocity in Meters per minute

So a part 300mm in diameter has a required RPM of

RPM = (4.5x1000)/( pi x 300)
= 4500/942.5
=4.8 revolutions per minute

A part 50mm dia

RPM= (4.5x1000)/( pi x 50)
= 4500/157
=28.6 RPM

(If surface speed is in feet per minute substitute 12 for 1000)
By having all parts at the same surface speed I can use one saturation graph for any diameter part because all parameters are constant!
If the table speed is fixed at say 20 RPM you will need a different saturation graph for a change in diameter as the T1 point would change.
The intensity value would not be different just the time it takes to reach T1.

Roy

Surely saturation graphs are produced just to determine the peening intensity of the shot stream. The time point on the graph, T1, that corresponds to the peening intensity is incidental. Keeping a constant surface speed should, however, help to ensure a steady coverage rate.

The T1 point will be reached sooner at a larger diameter causing the saturation graph to come up with a warning message. That is why we went to a constant surface speed.
It must be noted that this occures if you are working your saturation graphs out on number of rotations/ passes of the Almen strip past the shot stream, instead of time.
Consistant coverage rates was the other reason we looked at constant velocity V's fixed RPM
we peen parts from 1/2" diameter to 40 inches and found our table could not turn fast enough for the 1/2" part with out changing pressure and/ or flow rates causing us to come up with new saturation graphs.

Do you the nozzle to workpiece distance (standoff) when you peen different diameter parts? Have you tried to do saturation curve with turntable stopped and just using exposure time? As long as your shot stream blast pattern is large enough to (substantially) cover the Almen strip you can get a much faster (and still accurate) indication of intensity.

Just inquiring if it is possible to gauge a thread after it has been shot peened at an intensity of .008-.010 and still get the same stand off prior to shot peeneing?