More information about residual stress tester.

The residual stress in a metal do not depend on it hardness, but from the module of elasticity or Young module and from its chemical composition (density).
The hardness of a metal indicates its ability to absorb energy elastic, plastic or kinetic energy, but through it not possible to determine the value of residual stress. In a metal with the same hardness we will have a different values of this stress. Therefore, the problem will be to measure the values that vary so exactly proportional to the residual stress values in a given metal.

You will realize the convenience of this apparatus.
1) Portable and easy to use and very rapid. measuring point to point.high accuracy. 
2) NDT/NDE non-destructivetesting.3) Repeatable in unlimited number of times.
4) Not dangerous (X-ray).
5) Do not expensive. Effective for welding, hardened treatments, vessels control, bridges, pipes line, aeronautics, NDT inspection for every metal types.

p.i. Ennio Curto