Heat Input Influence on the Fatigue Life of Welds from Steel S460MC

Abstract

Fine-grained steels belong to the progressive materials, which are increasingly used in the production of welded structures subjected to both static and dynamic loads. These are unalloyed or microalloyed steels hardened mainly by the grain-boundary strengthening mechanism. Such steels require specific welding procedures, especially in terms of the heat input value. At present, there are studies of the welding influence on the change of thermomechanically processed steels’ mechanical properties, however mainly under static loading. The paper is therefore focused on the assessment of the welding effect under dynamic loading of welded joints. In the experimental part was determined the influence of five different heat input values on the change of weld fatigue life. As a result, there is both determination of five S-N curves for the double-sided fillet welds from the thermomechanically processed fine-grained steel S460MC and the quantification of the main influences reducing the fatigue life of the joint.