Corrosion performance of HASTELLOY B-3 alloy welds prepared by different welding methods

The corrosion performance of HASTELLOY®B-3® alloy weldments prepared by GMAW (Gas Metal Arc Welding/MIG Welding), GTAW (Gas Tungsten Arc Welding/TIG Welding) and SMAW (Shielded Metal Arc Welding/Stick Welding) was evaluated. Welded plates (0.5”-thick) and sheets (0.125”-thick) were investigated in this work. Overall corrosion loss rates in boiling 20%HCl were similar, irrespective of the type of welding procedure. Intergranular penetration attack occurred at the heat-affected-zones (HAZ) on all three as-welded 0.5”-thick plates, especially near the weld roots. The slightly deeper corrosion penetration attack of GMAW welds might be due to the higher heat input compared to that of GTAW and SMAW. PWHT (post-weld heat-treatment) significantly improved the intergranular corrosion resistance of the HAZ, especially in the thick plate welds. In contrast, the impact of PWHT on the corrosion performance of the thin-gauge sheet welds was negligible. In addition, no stress corrosion cracking (SCC) occurred on 0.125”-thick U-bend welded sheets prepared by GMAW, GTAW and SMAW.