Characteristics AVESTA P690 basic is a nickel base electrode with a basic type coating. P690 is suitable for many welding applications, such as joining nickel base alloys, e.g. Inconel 690 as well as for joining unalloyed or low-alloy steels to stainless steels and nickel base alloys. P690 is also well suited for depositing overlays on carbon steel, especially when there are stringent requirements regarding service at high temperatures, or in the construction of nuclear reactors. P690 is unsusceptible to sigma phase embrittlement and shows little tendency towards carbon diffusion. It is therefore very well suited for constructions in service at elevated temperatures. Interpass temperature: Max. 100°C. Heat input: Max. 1.5 kJ/mm. Heat treatment: Generally none (in special cases quench annealing at 1050°C). Structure: Fully austenitic. Scaling temperature: Approx. 1100°C (air). Corrosion resistance: Very good resistance to stress corrosion cracking in oxidising acids and water at high temperatures. Also very good resistance to intergranular corrosion due to the low carbon content and absence of sigma phase.