Sensitivity of UT methods in materials such as coarse‐grained steels depends on attenuation and noise, due to scattering by microstructural heterogeneities. Here, existing UT simulation tools developed at CEA are modified to account for experimental observations of noise and attenuation. A model‐based inversion tool is developed to estimate from experiments the parameters to input into the forward models. Example of application is given, showing the quantitative importance of these phenomena in terms of performance demonstration. © 2003 American Institute of Physics