Why do the root wall flanges of acid water stripping towers crack easily
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All the root wall flanges of our acidic water stripping tower are made of stainless steel, but these flanges often crack; neither ordinary welding rods nor stainless steel welding rods can resolve this issue properly. What is the cause of this problem, and how can it be fixed?
It is stress corrosion; heat treatment is required after welding.
Hydrogen sulfide corrosion. Even stainless steel pipes react with hydrogen sulfide and become corroded, but post-weld heat treatment improves the situation.
Here, it is mainly stress corrosion cracking; residual stresses remain in the stainless steel after welding, and there are intergranular corrosion-sensitive areas in the heat-affected zone resulting from welding. When stainless steel is welded, carbides tend to precipitate at the grain boundaries in the heat-affected zone; if no necessary heat treatment (such as stabilization treatment) is carried out after welding, the susceptibility of this area to intergranular corrosion **increases**.