254 SMO

The weld metal matches the superaustenitic base material with 6% Mo, generally provided in castings, and is used exclusively after post-weld solution annealing. Its very low carbon content minimizes the risk of carbide precipitation during heating cycles, as occurs for example during welding, and ensures a PRE value above 40. Thanks to the stable austenitic structure, the base material can be subject to hot cracking during welding, which is why it is crucial to operate with a low heat input. The solidification following partial remelting, as in the case of welding, leads to a redistribution of elements such as Mo, Cr, and Ni; these variations, or segregation, remain in the fused structure and can compromise its corrosion resistance in specific environments. This alloy was specifically developed for offshore platforms in the oil and gas sector, as well as for the pulp and paper industry. Major applications include equipment for seawater handling (cooling systems, ballast piping, fire extinguishing systems), components for pulp bleaching plants, tanks, and pipelines for chemicals with high halide content. It is recommended to operate with a heat input below 1.5 kJ/mm and maintain the interpass temperature below 100 °C.

6% molybdeno e acciaio inossidabile austenitico legato all'azoto.

Austenite.

• EN W.Nr.: 1.4547 (X1CrNiMoCuN20-18-7)
• UNS: S31254
• PROPRIETARY: 254 SMO (Outokumpu)