The stainless steel heat exchanger rusts after pickling and passivation
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What is the reason for rust formation near the pipe welds after acid washing and passivation of stainless steel heat exchangers? How to prevent it?
Was the welding rod used incorrectly? Otherwise, how could it rust?
If it’s not a problem with the welding materials, then it’s the surface after pickling – iron dust gets on it, leading to iron ion contamination and rusting.
It’s probably iron ion contamination; we’ve encountered this issue before as well.
During manufacturing, there were no CS products in the workshop
1 Weld, no rust； There is only rust on the base metal near the weld. 2 If stainless steel is welded using CS welding material, rust will appear during the humid and hot summer months, before acid cleaning and passivation.
Is it because the passivation wasn’t thorough enough and some areas were left untreated?
The area near the weld has been ground. . . It’s a bit rusty. .