A method for impact strength estimation

Abstract

The results of mechanical properties investiga-tions of pressure vessel and pipeline steels, such as tensile properties, Meyer’s hardness, HM, and impact strength are presented and discussed. The correlation between HM, load and recovered impression depth was investigated. The solution of the problem of indirect impact strength, KCV estimation for pipeline and pressure vessel steels, based on the IEF (Indentation Energy to Fracture) model, is present-ed. According to this model, fracture conditions occur when the stress z in the center of ball impression exceeds critical stress of brittle fracture f . The relationship be-tween critical indentation energy value Uf , according to condition z = f, and impact strength KCV can be de-scribed by unified linear equation: KCV = φ Uf. It was found that for all steels φ values depend on fracture stress Sk at the temperature 77 K. The present paper shows the possibility of impact strength KCV estimation in the transi-tion temperature range through the results of indentation and tensile tests.