Investigations into Fracture Mechanics Failure Concepts with ThermomechanicallyRolled Steels

摘要

The suitability of modern fracture mechanics failure concepts to ensure thesafety of components made of thermomechanically rolled steels was investigated. The new versions of the PD 6493 method based on crack tip opening CTOD and the R6 method were of particular interest. The investigations also dealt with the problem of extremely brittle areas in the heat-affected zone (HAZ) of submerged arc welded joints of TM steels. Special attention was paid to instrumented notched-bar impact bending tests and metallographic investigations on fracture mechanics test specimens with notch position in the HAZ during determination of parameters. The bearing load behavior of medium-sized tensile plates with inner and double outer notches up to 4 MN maximum load was evaluated by the failure concepts in order to obtain information on the suitability of the concepts by comparison with the test results.