Influence of energy input on the strength and hardness of welded joints

The changes in mechanical properties due to local energy input are important for welded joints. This affects both the base material in the area of the heat‐affected zone and the resulting weld seam. Extensive investigations on the influence of the cooling time t8/5, which is representative of the energy input, were carried out on a newly developed test specimen for determining the mechanical properties of welds. From these investigations, functional relationships between the strength class of the filler metal, the t8/5 time and the mechanical properties of the weld seam were derived. In order to evaluate the influence of multi‐layer welding, hardness measurements were carried out on individual weld beads at different levels of the welded joint. Furthermore, the relationship between the local hardness values and the integrally determined tensile strength was investigated.