Post-machining stainless-steel treatment
Pickling, passivation and electropolishing are available as part of the completed-component route. Treatment selection depends on alloy, surface condition, cleanability, appearance, corrosion exposure and the applicable customer specification.
After proper cleaning and descaling, passivation is used to remove free / exogenous iron contamination and support the stainless steel’s normal passive surface without intentionally changing part geometry. It is not a coating. Electropolishing removes a controlled microscopic layer, smooths peaks and can improve cleanability and appearance. It is not a substitute for correcting deep casting defects, tool marks or inaccessible geometry.
Before treatment
Machining residue, polishing compound, embedded contamination and heat tint must be addressed through the agreed cleaning route. Threads, sealing surfaces, close-tolerance features and identification marks may require masking or special handling. Mechanical polishing should be completed to the correct precursor condition before electropolishing.
Dimensional and surface considerations
Electropolishing removes material from all exposed surfaces, with local removal influenced by geometry and current density. Tight edges, threads, thin sections and close fits therefore need a defined allowance and post-treatment verification. Roughness acceptance should identify the measurement location and method.
Acceptance
The drawing should define the governing specification, required surface condition, sampling plan and any corrosion, cleanliness or iron-contamination verification. When a visual standard is important, an approved sample and agreed lighting conditions reduce ambiguity.