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A 9-12% Cr ferritic steel weld metal containing 1% Co partially substituted for nickel was prepared by submerged arc welding processing(SAW). The microstructures and creep properties of the weld metal have been investigated. The microstructure exhibited a fully tempered martensitic structure free of δ-ferrite. The creep properties of the obtained weld metal are inferior to that of the P92 base metal at 600 and 650 . The values of A and n for weld metal in Norton power law constitution at 650 are 1.12×10-21 and 8.14, respectively.

A 9% Cr ferritic steel weld metal containing 1% Co, partially substituted for nickel, was prepared by submerged arc welding (SAW) processing. The microstructure and creep properties of the weld metal were investigated. The microstructure exhibited a fully tempered martensitic structure free of δ-ferrite. The creep properties of the obtained weld metal were inferior to those of the P92 base metal at 600 and 650 °C. The values of A and n for weld metal in the Norton power law constitution at 650 °C are 1.1×10−21 and 8.1, respectively.

The creep rupture behaviour,hardness distribution and microstructure of weldment made by submerge arc welding for W strengthened P92 steel are described in this paper. The cross-weld creep tests were carried out at 923K under stresses in the ranges 130-100MPa. For stress below 120MPa, weld-joints were ruptured by the Type crack, which located in their fine-grained heat affected zone(FGHAZ)with the smallest measured cross-weld hardness. A strong drop in creep rupture strength of weldment was induced by brittle type failure. In addition to coarsening of M23C6 carbides and an equiaxed fine grains in FGHAZ, intermetallic Fe2(Mo,W)Laves phase precipitated on grain boundaries during creep is probably the significant factor caused the type failure.