High dilution submerged arc welding of Cr–Ni–Mo austenitic stainless steel

Improvements in the submerged arc welding (SAW) of Cr–Ni–Mo austenitic stainless steel have been achieved from a combination of simplified edge preparation, intermediate heat input, and high dilution (75–80%). The cost benefit is 83% compared with the previously used practice. Mechanical properties of the weld metal in a square edge preparation showed a decrease in yield and tensile strengths, but a significant improvement in toughness compared with the Y preparation weld metal. Thin foil transmission electron microscopy confirmed the presence of χ phase in some areas of the Y preparation weld metal, and M₂₃C₆ in some areas of the square edge preparation. This has been related to the incidence of fewer reheated and cooled areas in the square edge preparation weld. The reduced precipitation has influenced the toughness characteristics of the square edge preparation weld metal.