Pickling issue
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The drawing only mentions acid washing of the stainless steel surface of the equipment – does this refer to the outer surface or the inner surface?
It should be both the inside and the outside; when I design, if I focus on one aspect, it definitely indicates that~
It generally refers to the inner surface in contact with the medium
It should be the inner and outer surfaces. Another factor is the specific medium; for ordinary media, only the outer surface is treated, for aesthetic reasons!
Yellow stains can appear during the stainless steel manufacturing process, especially on the inner surfaces.
It generally refers to the inner surface, that is, the surface in contact with the medium, while the outer surface is usually cleaned only at the weld area. For aesthetic reasons, if insulation treatment is applied, there is no need to clean the weld area at all.
Reply to 6# chinacleaning: I agree with what you said
It should be the inner and outer surfaces; that’s how it is for us
We usually have the inner surface in contact with the medium, while the outer surface is at least pickled and welded for aesthetic reasons.
Unless otherwise specified, it refers to the inner surface. For corrosion protection, it is definitely meant to prevent corrosion by media, not by air.
The inner surface is pickled and passivated to prevent corrosion by media; for aesthetic reasons, the weld areas on the outer surface also need to be pickled