Almen strips, N, A, and C is not about the capability of the Almen gage it's about the strips themselves an the reproducibility of the process.
Think of N strips as ounces, A strips as pounds an C stipes as tons. You need to use the right scale to get the most accurate measurement.
The intensity range is a process measurement, it's what the process is capable of repeating, the range options listed in AMS2430 have nothing to do with strip or gage capability.
"The 30% rule sets the arc height limits for 4A at .004” to .005”
No, The intensity range is .004-.007A True 30% of .004 = 0.0012 and to the nearest .001 would make the range .004-.005A. However, AMS2430 goes on to say that the minimum range is either 30% of the nominal value or .003" whichever is greater. .003 is greater than .001, therefore the range is .004-.007A.
The 30% rule would only come into play if the nominal intensity value was .012 or greater.
.010 would be .010-.013
.110 would be .011-.014
.012 would be .012-.016 This is the first value where 30% would be greater than .003, .0036 actual rounded up to the nearest .001.
and so on.
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