Microstructural and mechanical properties of electron beam welded super duplex stainless steel

• Published in: Welding in the world 2024-08, Vol.68 (8), p.1929-1940
• Main Authors: Tóth, Tamás, Hesse, Ann-Christin, Kárpáti, Viktor, Mertinger, Valéria, Dilger, Klaus
• Format: Article
• Language: English
• Subjects: Chemistry and Materials Science; Materials Science; Metallic Materials; Research Paper; Solid Mechanics; Theoretical and Applied Mechanics
• ISSN: 0043-2288; 1878-6669
• DOI: 10.1007/s40194-024-01680-1

The electron beam welding of super duplex stainless steels is associated with challenges due to the concentrated heat input and the nitrogen loss that result in a predominantly ferritic structure after the solidification. This study presents an approach to overcome this issue by feeding nickel-based filler wire into the melt pool in welding of 2507 super duplex stainless steel. Results showed that the high-frequency beam oscillation combined with a multi-beam technique led a good mixing between the base metal and the filler wire, even at a large depth-to-width ratio. Additionally, the weld geometry was characterized by near-parallel fusion lines and a narrow heat-affected zone. The nickel addition resulted in a balanced microstructure in the weld metal with ferrite fractions of 35–55 %, despite a significant nitrogen loss, consequently leading to impact energy values of 215 ± 15 J and hardness values of 285 ± 15 HV. The findings of this investigation allow fabricators to effectively design electron beam welding processes for producing thick-walled super duplex stainless steel components.