Characterization of the Crack Initiation and Crack Propagation Behavior of Welded Steels by Means of the Replica Technique

Abstract

The replica technique was applied to evaluate crack initiation and crack propagation behavior of welded joints on high strength structural steel with a minimum yield strength of 690MPa. Wöhler tests (cyclic loading tests) on these high strength welded joints, supported by the replica technique, show, that at a given particular stress amplitude, crack initiation occurs in several areas of the heat affected zone. At high stress amplitudes, the failure occurs in the intercritical zone, whereas stress amplitudes near the endurance limit lead to a failure within the coarse grained zone. This can be attributed to the crack initiation and propagation behavior within these individual zones. Evidence for this can very well be provided by means of the microstructure replica technique described in this article.