APPLICATION OF MINIATURE TESTING SPECIMENS FOR MECHANICAL CHARACTERIZATION OF MATERIALS AFTER HEAT TREATMENT

One of the methods of evaluating the mechanical properties of a material in the case of its limited amount is the use of techniques that employ the miniaturized test specimens. The basic properties used mostly for residual life evaluation are tensile strength, impact notch toughness or impact notch toughness transition curve, fracture toughness, creep and high cycle fatigue.

For example, by semi-destructive sampling of operating power equipment, actual material properties can be obtained which are crucial for predicting the residual life of the equipment. Furthermore, the local material properties of the weld joint in individual zones can be determined. In this paper applicability of these test methods is described, specific examples of use are given and reference is made to the existing ISO/ASTM 52909:2022 standard for the use of sub - size samples.

Key words: weld characterization, Extended Continuous Cooling Transformation, ISO/ASTM 52909:2022, local properties, miniature sample test technique, tensile properties, mini-Charpy, fracture toughness, fatigue, creep.