Abstract
Nodestructive-Testing-Technology is divided into three categories: - ndt for defects, - ndt for stresses. The major mechanical properties describe the nonelastic - that means nonreversible - behaviour of materials, which physically is not correlated to elastic behaviour; however, only testing in the elastic area is nondestructive. Consequently due to this physical reasons ndt for mechanical properties in a direct manner is not possible or at least much more difficult than ndt for defects and ndt for stresses. Physical properties such as electric, thermal, magnetic, etc. ones can be measured using ndt techniques. They strongly correlate with the microstructure of materials.