Pickling & Passivation
Remove qualifying oxide, scale, heat tint, and surface contamination, then support the corrosion-resistant passive condition of compatible stainless steel.
Pickling and passivation solve different surface-condition problems.
Pickling is an acid-based descaling process used to remove heat tint, oxide scale, embedded contamination, and a thin layer of affected stainless-steel surface. Passivation treats a chemically clean stainless surface to reduce free iron and promote formation or restoration of the chromium-rich passive film.
Neither process should be described as cosmetic polishing, and passivation is not intended to remove heavy weld oxide by itself. The correct sequence depends on stainless grade, heat treatment, fabrication history, weld condition, finish, dimensional restrictions, downstream service, customer specification, and required acceptance test.
Select the treatment from the alloy and actual surface condition.
A combined cleaning, pickling, passivation, testing, and packaging sequence may be required; the names are not interchangeable.
Pre-Cleaning
Remove oil, grease, dirt, machining fluid, marking compounds, and process residue that can interfere with treatment.
Pickling
Use approved chemistry to remove qualifying oxide scale, heat tint, and affected surface metal.
Passivation
Treat a clean stainless surface to reduce free iron and support the passive oxide condition.
Rinse Control
Neutralize or rinse thoroughly and prevent retained chemistry, staining, or cross-contamination.
Acceptance Testing
Apply the specified visual, water-break, free-iron, humidity, copper-sulfate, or other approved test.
Handling & Protection
Dry, handle, segregate, package, and document the treated component to preserve the surface condition.
From alloy identification to verified surface treatment.
The treatment route is confirmed against the governing customer or industry specification and the part’s condition.
Identify the alloy
Confirm stainless grade, heat treatment, finish, weld history, dimensions, and prohibited chemistries.
Inspect the surface
Document oil, scale, heat tint, corrosion, free iron, coatings, markings, and required appearance.
Pre-clean
Remove organic soil and interfering contamination before acid-based treatment.
Pickle or passivate
Apply the approved chemistry, concentration, temperature, time, agitation, and sequence.
Rinse, neutralize & dry
Remove residual treatment chemistry and control water quality, staining, and trapped liquid.
Test & protect
Complete the specified acceptance test, record results, and package the treated part.
Define the alloy, finish, surface defect, and acceptance test.
Surface-treatment chemistry cannot be selected safely from a photograph alone.
Heavy oxide, heat tint, scale, damaged base metal, incompatible alloy conditions, and cosmetic-finish requirements may require pickling, mechanical treatment, electropolishing, repair, or another route before—or instead of—passivation.
- Part drawing, photographs, dimensions, quantity, stainless grade, heat treatment, and material certification
- Welds, heat tint, oxide scale, corrosion, machining history, embedded iron, coatings, and markings
- Required finish, allowable etch, dimensional tolerance, masked areas, and appearance restrictions
- Customer, ASTM, AMS, aerospace, medical, food, or other governing specification and revision
- Required passivation method, treatment chemistry restrictions, and acceptance or free-iron test
- Rinse-water quality, drying, clean handling, packaging, downstream service, documentation, and schedule
Build the complete Haygor service route.
Connect this service with related cleaning, machining, repair, calibration, coating, or assembly work when the application requires a broader scope.
Send the alloy, surface condition, specification, and acceptance test.
Haygor can determine whether the part requires pre-cleaning, pickling, passivation, or a combined sequence.