Copper-Nickel-Silicon Precipitation Structure
A finely dispersed precipitate structure of nickel silicides in a copper matrix to achieve high spring temper and thermal stability.
This is a hardenable copper material, not a normal welding topic. When welding, you must be careful that the heat input doesn't get too high, otherwise you'll lose the base hardness in the component. The hardening itself doesn't happen through welding, but is a subsequent heat treatment step – welding messes up the microstructure first. If you weld the part, you'll get a softer structure in the weld metal and heat-affected zone, which you have to bring back to the desired condition by solution annealing and subsequent aging. Sounds like a job for the furnace, not for the pliers – you need to know exactly what you're doing, otherwise you'll end up with a part that doesn't deliver the required spring hardness.