Selectarc Co21S

This Selectarc Co21S electrode is a cobalt-based hardfacing electrode, designated « Grade 21 » type, featuring a rutile-basic coating. It boasts a deposition of « Stellite grade 21 » (Co-Cr-Mo-Ni), offering excellent wear and oxidation resistance up to 1000°C, even in the presence of sulphurous atmospheres. It demonstrates robust behaviour to thermal and mechanical shocks, superior resistance to cracking, cavitation, and erosion, and is non-magnetic. It’s ideal for demanding applications requiring high-performance surface protection.

This electrode is specifically designed for hardfacing a variety of components subject to extreme wear and thermal stress. Potential applications include surfacing motor valves, gas turbine blades, extrusion nozzles, forging dies and tools, mixers, and valves handling gas, water, vapour, or acids. Preheating massive pieces to 250-400°C and maintaining this temperature during welding, followed by a slow cooling process, is recommended to minimise the risk of cracking. Consider using Selectarc B90 for any cushion layers.