When is it necesary to passivate stainless steel kettles and tanks?

One would think that this equipment would come from the manaufacturer already passivated and or electroplated?

What are the merits of passivating used stainless equipment?

Dear pingpong,

the passive layer of mixed oxides (cromium et al) withstands water, but not neccesarily corrosion promoters and definitely not mechanical wear. Normally it is not necessary to (re)passivate tanks and kettles, but equipment permanently in contact with flowing water (which leaches out ions, sometimes later depositing them as rouge) and especially equipment in contact with chlorides and other corrosion promoters may need a new buildup of a passive layer.

Best regards


Does anyone have a link/copy to ASTM A967?

(It amazes me that critical validation information is always a secret, or you have to pay big $$ to get it. If it were readily available, then perhaps there would be more companies in cGMP compliance)