Plasticity of bead-on-plate welds made with the use of stored flux-cored wires for offshore applications

Abstract

Extreme atmospheric conditions in the marine and offshore industry are harmful to engineering materials, especially to welded joints, and may cause degradation of their properties. This article presents the results of research on the plasticity of bead-on-plate welds made using two types of seamless, copper plated flux-cored wires. Before welding, spools with wire were stored for 1 month in two distinct locations with different geographical and industrial conditions in Poland, and then subjected to visual examination. Bead-on-plate welds were subjected to a static tensile test and on this basis plasticity indexes showing the effect of storage on plasticity were determined. The fractures after tensile tests and the surfaces of the wires were examined on an electron scanning microscope. Additionally, diffusible hydrogen content in deposited metal measurements for each condition were carried out. The highest degradation level was found for wire stored in an agricultural building in north-eastern Poland-there was an almost fourfold decrease in the plasticity index value and the highest diffusible hydrogen content. For the same wire and the same location, the largest difference was also observed in fracture morphology after the tensile test-ductile fracture was obtained for wire at delivery condition while an almost full cleavage fracture was found after relatively short (1 month) storage of wire.