Predicting the critical stress intensity in structural steels

Abstract

A method is proposed for predicting the critical stress-intensity coefficient K_1c of structural steels (their crack resistance) on the basis of uniaxial tensile tests of standard samples. The derivation of this method relies on the concepts of mechanical stability and embrittlement when nonuniform force fields act on a metal. The strain-hardening index n of the metal at the critical transition temperatures from the plastic state to the quasi-brittle state (T_c or T₀) and from the quasi-brittle state to the brittle state (T_k2) plays a key role here. The proposed method may prove effective in monitoring the crack resistance of steels certified in scientific and plant laboratories.