The measurement uncertainty of reduction in area of metals in tensile testing system

Abstract

International Standard ISO 6892-2 maintains that the strain rate variations and test temperature variations can induce the measurement uncertainty of mechanical properties in tensile testing, which will imperil the reliability of tension tests. In this paper, the measurement uncertainty of reduction in area is first described experimentally. Second, the fundamental results on the microscopic theory of elastic deformation in metals were briefly mentioned. Then the measurement uncertainty is clarified based on this theory. It is shown that the elastic deformation of tension test induces the segregation of impurities to grain boundaries and the relevant embrittlement which produces the measurement uncertainty of reduction in area in tensile testing. This work gives a theoretical basis for correcting the present tension testing system to avoid the measurement uncertainty of reduction in area.