The evaluation of materials properties of inservice components by small punch tests

Residual lifetimes and/or structural integrity assessments of critical components of mechanical plants and/or steel structures reąuire the knowledge of actual mechanical properties of the components' materials, because the material properties could be reduced throughout a service life by ageing. the use of standardised mechanical test techniques for determination of actual mechanical properties of the components under operation can cause its considerable damage due to size of necessary testing material and following repairs by welding. The need of a large amount of testing material can be eliminated by new advanced testing method based on „ non destructive " sampling of a small amount of testing material from the component surface. the mechanical characteristics are then determined by Small Punch) Tests (SPT). This paper describes the use of this advanced test technique for determination of tensile properties and fracture characteristics (FATT, J IC) of materials. The small punch test technique provides at present time a vehicle for determination of actual tensile and fracture properties necessary for optimisation of operating procedures and inspection intervals as well as for repairs strategies and residual lifetime assessment.