Metallurgical, strength and toughness evaluation on F22 steel welding with ER80S-G and nickel-based filler metals

This work evaluates the AWS ER80S-G filler metal in buttery welding and F22 steel joint, in technical and economic replacement of ERNiCrMo-3 wire (Inconel 625). The metallurgical and mechanical characterization of buttery weld interfaces was performed using optical microscopy and scanning microscopy (SEM), energy dispersive spectroscopy and microhardness. The joints fracture toughness was estimated by crack tip opening displacement test and the fracture mechanism by SEM. To evaluate hydrogen embrittlement, samples were hydrogenated with a 0.1 M H 2 SO 4 solution and tested by uniaxial tensile test. The microstructural results revealed that ER80S-G interface did not present any partially mixed zone (PMZ), differently the Inconel 625 interface. The PMZs presence in F22/Inconel 625 interface did not reduce the welded joint toughness. The hydrogen presence in the welded joints reduced the ductility and mechanical strength of F22 steel, in addition to changing the ductile fracture mode to brittle mode.