Mechanical rolling and annealing of wire-arc additively manufactured stainless steel plates

Thin walls of 304L stainless steel were fabricated by wire-arc additive manufacturing (WAAM) followed by post-build thermomechanical processing to modify the as-built microstructure and properties. The walls were made using a high-deposition-rate robotically controlled gas metal arc welding system and were characterised using optical microscopy and tensile tested for mechanical properties. Post-processing consisted of mechanical rolling the walls to 25% and 40% strains, followed by annealing at 1050 degrees C to demonstrate a wide range of properties. Results show that WAAM can be used to build custom-sized semi-finished parts or blanks that can later be thermomechanically processed to increase strength and ductility through recrystallisation of the as-built microstructure, and/or processed into desired shapes with improved mechanical properties.