Filler metal ER308 provides good strength, but not similar corrosion resistance and no wear or galling resistance in the deposit.
Information from "Welding Nitrogen-Strengthened Stainless Steels" (R.H. ESPY, AWS Welding Research Supplement, May 1982) follows:
Welding with EB (Electron Beam) can be achieved using slower welding passes or utilizing a two pass technique.This helps to provide more time for outgassing of the Nitrogen, which if trapped causes porosity. The outgassing of Nitrogen is proportionate to the amount of Nitrogen contained.
Matching fillers should contain a lower amount of Nitrogen than the base. This helps to control weld porosity as well.