What is the purpose of post-braze annealing for certain joints?

• A. Relieves residual stresses and may improve ductility
• B. Increases hardness
• C. Removes all filler metal
• D. Causes oxidation of the joint

Answer: (A)

Post-braze annealing primarily relieves residual stresses from the brazing process and can improve the joint’s ductility. When metals and filler metal cool after brazing, differences in contraction create internal stresses that can make the joint brittle or prone to cracking under load. Annealing gives atoms time to rearrange at elevated temperature, relaxing those stresses and often reducing brittleness, which helps the joint deform more plastically in service. The filler metal stays in place, so removing it isn’t the goal of this step. Increasing hardness isn’t the aim; annealing typically softens or maintains ductility rather than hardening. Oxidation is undesirable, so this heat treatment is done in a controlled atmosphere to prevent it, not to promote it.