What type of corrosion is this?
Thread Content
Experts: The material was originally 316L; after being pickled for some time, it became like this. What could be the reason?
I personally think it’s carbon steel that’s causing the contamination
Carbon steel is contaminated. Before pickling, all splatter and debris on the carbon steel should be polished away; doing so will prevent this problem during pickling!
Is the material stainless steel?! It seems that if only surface cleaning is required, acid washing should be avoided, as chloride ions can easily cause pinhole defects on the surface of stainless steel
I asked an expert, and he said that when polishing the iron frame on the edges, nothing was used to shield it, so the sparks landed on the equipment; over time, that’s what happened
Avoid using hydrochloric acid for pickling 316L; residual chloride ions can facilitate corrosion. Acetic acid, citric acid, etc. can be used, along with a small amount of corrosion inhibitor