254 SMO

The weld metal corresponds to 6%Mo superaustenitic parent material, typically castings, and is exclusively employed when applying post-weld solution annealing. With an extremely low C content, there is minimal risk of carbide precipitation during heating, such as in the welding process. It exhibits a PRE number exceeding 40. The base metal, with its stable austenitic structure, can be prone to hot cracking during welding, necessitating the use of low heat input. Solidification following partial remelting, as in welding, results in the redistribution of elements like Mo, Cr, and Ni. These segregations persist in the cast structure of the weld and can compromise the material's corrosion resistance in specific environments. Engineered specifically for use in oil and gas offshore platforms and the pulp and paper industry, this material finds common applications in equipment handling seawater, including seawater cooling, cooling water pipes, ballast water systems, firefighting systems, equipment in pulp bleaching plants, as well as tanks and pipelines for chemicals with high halide contents. It is advisable to maintain a heat input of <1.5 kJ/mm and an interpass temperature of <100°C.

6% molybdenum and nitrogen-alloyed austenitic stainless steel.

Austenite.

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