Abstract
The present study was carried out to clarify the effect of neighboring mechanical heterogeneity on the ductile-to-brittle transition behavior of steel in the Charpy impact test. Specimens were manufactured from a high tension structural steel with bead welding by electron beam weld. Instrumented Charpy test was carried out in the transition temperature range. The resuts of the Charpy test were shown to be dependent not only on the toughness of weld metal but also the mechanical properties of base metal in the vicinity of weld metal. The mechanical heterogeneity existing in the neighborhood of the notch root decreased the upper shelf energy and raised the transition temperature in the Charpy test of specimens with weld bead.
In addition, the elasto-plastic analyses on stress and strain in the Charpy specimen with weld bead were conducted by using finite element method. The analyses showed why the upper shelf energy and the transition temperature were affected not only by the toughness of weld metal under the the notch root but also the mechanical properties of base metal in the vicinity of weld metal.
