Rejuvenation of weld decayed alloy 82 by laser surface treatment

Laser surface treatments were studied for their feasibility in repairing the decayed Alloy 82 weldment where the weld decayed zone is rejuvenated and corrosion resistance is recovered. Modified Huey test was employed to reveal the width of rejuvenated area, and double loop-EPR test was employed to evaluate the corrosion resistance of each specimen. The experimental results showed that interdendritic pitting resistance of laser treated specimens was remarkably improved both in melted zone and heat affected zone where Nb-rich phases were resolved. However, TiC/NbC or (Nb,Ti)C particles remained unresolved in the heat affected zone. As a consequence, heat affected zone had a superior mechanical strength than melted zone. The DL-EPR results revealed that laser treated areas with lower reactivation current and degree of sensitization values (DOS, Ir/Ia) indicated higher corrosion resistance. Hence, laser surface treatment is proven to be a practical technique for repairing the decayed Alloy 82 weldment.