High dilution submerged arc welding of Cr-Ni-Moaustenitic stainless steel

Improvements in the submerged are welding (SAW) of Cr-Ni-Mo austenitic stai nless steel have been achieved from a combination of simplified edge prepar ation, intermediate heat input, and high dilution (75-80%). The cost benefi t is 83% compared with the previously used practice. Mechanical properties of the weld metal in a square edge preparation showed a decrease in yield a nd tensile strengths, but a significant improvement in toughness compared w ith the Y preparation weld metal. Thin foil transmission electron microscop y confirmed the presence of chi phase in some areas of the Y preparation we ld metal, and M23C6 in some areas of the square edge preparation. This has been related to the incidence of fever reheated and cooled areas in the squ are edge preparation weld. The reduced precipitation has influenced the tou ghness characteristics of the square edge preparation weld metal. Dr McPherson is with BAE Systems Govan (formerly Kvaerner Govan Ltd), Glasg ow G51 4XP, UK, Professer Baker and Dr Li are in the Metallurgy Group, Depa rtment of Mechanical Engineering, University of Strathclyde, Glasgow, UK, a nd Dipl. Ing. Hoffmann is with Schweisstechnische Lehr- und Versuchsanstalt , D-18059 Rostock, Germany. Manuscript received 21 April 1999; accepted 1 J une 1999. (C) 2000 IoM Communications Ltd.