SMAW, MCAW, FCAW and SAW high strength ferritic deposits: the challenge is tensile property

Abstract

The objective of this work was to analyze the influence of chemical composition and welding parameters on microstructure and mechanical properties of medium and high strength steel all weld metals of both C-Mn-Ni-Mo and C-Mn-Ni-Mo-Cr ferritic types produced with coated electrodes, flux cored arc welding electrodes and wire/flux combinations for submerged arc welding and compare these results with AWS requirements. Chemical composition of the deposits was varied and welding parameters were changed in the production of all weld metal samples according to the relevant AWS standards of the consumables employed. Tensile properties, hardness and Charpy-V impact toughness of the all-weld-metal specimens were assessed and metallographic studies were conducted with light microscopy in order to correlate mechanical properties with resulting microstructures. From the analysis of the results it was concluded that achieving the toughness required by the standards was not a problem. On the contrary, consistently satisfying the minimum requirements for tensile strength turned out to be much more difficult, demanding a rigorous approach to welding parameters selection in order to obtain repeatable results. On the other hand, for a given type of weld deposit the requirements to be met differ according to the welding process employed thus adding another variable to the difficulties to satisfy the tensile requirements of the different standards.