Is pickling and passivation always required after welding?

Mandatory: food and pharmaceutical equipment, seawater and chemical service, and any weld with hygiene or corrosion acceptance criteria. Can be simplified: indoor decorative parts, non-corrosive media, and parts that receive a full surface treatment afterwards such as overall pickling or electropolishing. Alternative: local mechanical grinding plus electropolishing reduces acid consumption, but grinding must completely remove heat tint. Otherwise the passive film cannot be restored. Acid waste must be treated according to local environmental regulations and never discharged directly.