Welding C-22
Any modern welding power supply with adequate output and controls can be used for common fusion welding. Generally, weld heat input is controlled in the low to moderate range. Stringer bead welding techniques—with some electrode/torch manipulation—are preferred. Wide weave beads are not recommended.

Nickel-based alloys generally exhibit sluggish welding and shallow penetration characteristics; so, the possibility of incomplete fusion increases. Care must be used to ensure that sound welds are achieved. Nickel-based alloys have a tendency to crater crack; so, grinding of starts and stops is recommended.

Cleanliness is critical when welding nickel-based alloys. Contamination by grease, oil, lead, sulfur, or other low melting point elements can lead to severe cracking problems. The welding surface and adjacent areas should be cleaned thoroughly with an appropriate solvent such as 99.9% isopropanol (IPA). Prior to any welding, all foreign matter—grease, cutting fluids, crayon markings, scale—should be removed.

Post Weld Heat Treatment
In the majority of corrosive environments, C-22 products
are used in the as-welded condition. Post-weld heat treatment—full solution annealing (1900°-2150° F) or stress relief annealing (1100°-1200° F)—is usually not required.

Annealing is often performed after cold working operations to restore ductility if the cold work is above 7% outer fiber elongation. A full solution anneal at 1900°-2150° F is required for C-22; stress relief temperatures used on stainless steel (1100°-1200° F) are not effective and may actually promote alloy precipitation detrimental to corrosion resistance.

Quenching
To prevent the precipitation of secondary phases, rapid cooling is required after solution heat annealing. Rapid air cooling can be used on sections thinner than 3/8" (9.5 mm), but water quenching is essential on material thicker than 3/8", and is the preferred method for all thicknesses. The time taken to transfer the material from the furnace to rapid cooling must be less than three minutes.