Corrosion Resistance of Welds

To assess the resistance of welds to corrosion, Haynes International has chosen to test all-weld-metal samples, taken from the quadrants of cruciform assemblies, created using multiple gas metal arc (MIG) weld passes. Interestingly, the resistance of all-weld-metal samples of G-35 alloy to key, inorganic acids is close to that of the wrought, base metal, and even exceeds it in concentrated sulfuric acid.

Chemical Concentration Temperature Corrosion Rate
wt.% °F °C Weld Metal Wrought Base Metal
mpy mm/y mpy mm/y
H2SO4 30 150 66 <0.4 <0.01 0.4 0.01
H2SO4 50 150 66 <0.4 <0.01 <0.4 <0.01
H2SO4 70 150 66 56.3 1.43 63.8 1.62
H2SO4 90 150 66 66.5 1.69 122.8 3.12
HCl 5 100 38 <0.4 <0.01 <0.4 <0.01
HCl 10 100 38 9.4 0.24 6.7 0.17
HCl 15 100 38 22.0 0.56 20.5 0.52
HCl 20 100 38 17.7 0.45 16.5 0.42
HNO3 70 Boiling 4.7 0.12 3.9 0.10
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