Nickel-Chromium Carbide Network
The discrete precipitation of chromium carbides along grain boundaries in nickel-based alloys, which increases creep resistance at high temperatures. Uncontrolled formation, however, can lead to intergranular corrosion.
Nickel-chromium carbide networks form when chromium carbides precipitate at the grain boundaries. This happens at certain temperatures and can improve creep resistance if it occurs in a controlled manner. When welding, you have to be careful: if you heat the material for too long or too hot, the carbides precipitate uncontrollably. Then the structure at the grain boundaries becomes depleted of chromium and the material is prone to intergranular corrosion. So keep the heat input as low as possible and do not let the component cool unnecessarily in the critical temperature zone after welding. If you have the choice, use a low-alloy filler material that reduces carbide formation.