Fracture Toughness of Welded Commercial Lean Duplex Stainless Steels

• Published in: Welding in the world Vol. 53; no. 3-4; pp. R24 - R33
• Main Authors: Sieurin, Henrik, Westin, Elin M., Liljas, Mats, Sandström, Rolf
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.03.2009
• Subjects: Chemistry and Materials Science; Materials Science; Metallic Materials; Peer-Reviewed Section; Solid Mechanics; Theoretical and Applied Mechanics; Toughness; Reference lists; Welding; Duplex stainless steels; Mechanical properties; Steels; Stainless steels; Fracture toughness
• ISSN: 0043-2288; 1878-6669
• DOI: 10.1007/BF03266700

Duplex stainless steels are successfully used in pressure vessel applications due to high mechanical strength combined with superior corrosion resistance. There has been a debate concerning the toughness level of welds in duplex stainless steels. For this reason, fracture and impact toughness data were generated for 30 mm thick parent material and welds of two commercial duplex stainless steels; LDX 2101 (EN 1.4162, UNS S32101) and 2304 (EN 1.4362, UNS 32304). Welds were produced with flux core arc welding (FCAW) and resulting microstructures and mechanical properties are presented. These show that both steels exhibit high fracture toughness in base metal and welds, close to what was earlier obtained for the more common grade 2205 (EN 1.4462, UNS S31803). Fracture toughness data were evaluated with the master curve approach giving a reference temperature characterizing the onset of cleavage cracking. The reference temperatures were below −100 °C for the parent materials and around −100 °C for the welds. Established relations were used to correlate impact and fracture toughness transition temperatures. The results verify that these steels have satisfactory fracture toughness properties and that this can be predicted from impact toughness data.