The effect of pickling solution concentration on stainless steel
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Our company sent SS316L pipes for pickling. The transport tie rods used for the expansion joints are made of SS304. There were no problems with pickling in previous instances, but this time, upon returning them, it was found that several areas of the stainless steel tie rods had been corroded unevenly. The quality of the material itself was fine, so we suspect that this was caused by an excessive concentration of the pickling solution. Does anyone who knows something about this matter please help analyze it? Another batch of 304 stainless steel pipes developed gray spots after acid washing, while some did not have any problems. So, which elements in 304 pipes cause this issue? Could there be an elemental critical point?
The S304L has been corroded to this extent; I’m not sure if this will have any impact on our S316L Will it thin out?
This transport tie rod is probably made of 304. . . .
Pickling acid should be sulfuric acid combined with other substances; if it’s just sulfuric acid, there shouldn’t be any problem
There is a certain concentration of hydrochloric acid, but the ratio is unknown. It seems the concentration is too high.
The material has been tested and there are no issues; it is indeed 304.
The reason must lie in hydrochloric acid; it’s this substance that causes corrosion
However, the supplier still doesn’t show us the ratio and such; we also suspect there is a problem with the pickling solution.