Home Forums General Discussion Equipment, Machines, Accessories Almen strip for shot peening of holes

David,

The proper method to measure the intensity of holes under .750" is to use a shaded strip.

You did not mention what your intensity range is. I'll use .004-.007A as an example.

First you have to develop a coloration. This is done by generating a saturation curve on a fully exposed "A" strip as you normally would. This can be done in any machine in any set up. Once you have established your intensity peen a shaded "N" strip ( in this example you would be exposing .600") in the exact same set up.

Lets say the intensity point for the fully exposed "A" strip was .0064A
The shaded "N" strip reads .0132N Therefore .0132N = .0064A


Now you can play around with the pressures and shot flow to come up with min / max limits
Example .0105N = .004A .014N =.007A

Now you can peen the shaded strip in your lance peening set up. As long as it is within .0105-.014N your good to go.

If your intensity range is over .009A then you can use an "A" strip for both. An "N" strip is used for .009A and below to give a larger arc reading.

Hope this helps,

-Walter