More information about residual stress measurement NDT/NDE


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.
The residual stresses tend to equilibrate themselves in the surface of the material.
The measurement made with all the major methods, X-ray, string gauge (destructive), optical etc. the residual stress is determined between the measuring the displacement of the equilibrium point the reticule crystalline.
The method discovered analyzes the value of acceleration vibratory generated by an impulse to constant energy with the subsequent reaction elastic (elastic field) from the metal, The equipment does not recognize the value of compression from that of tensile stress. It gives the value of the space resulting or volume but with the applying of a triaxial accelerometer we can have forces values axis x, y, z.
You will realize the convenience of this apparatus.
1) Portable and easy to use and very rapid, high accuracy.
2) NDT/NDE non-destructive testing.
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.