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STAINLESS STEEL SURFACE TREATMENT

Stainless Steel Passivation
Services for Machined Parts

Remove free iron and processing contamination from stainless steel parts, then specify the chemistry and verification method required for your application.

Get a Quote ↗Review Process Requirements ↓
Stainless steel parts prepared for passivation
Existing stainless-steel part example. Appearance alone does not prove passivation or a test result.
Stainless steelGrade and condition required
Nitric or citricChoose the specified chemistry
Clean surfaceDescale and weld review
Lot evidenceDefine acceptance testing

Passivation is a surface-cleanliness process,
not a decorative coating.

Passivation accelerates formation of the protective passive film on a chemically clean stainless-steel surface. It does not add plating thickness or create a hard wear layer.

Scope to define in your RFQ
MaterialStainless-steel grade, product form, heat condition and prior operations. Do not specify only “stainless”.
Chemistry routeState nitric, citric or electrochemical treatment when required by the drawing or customer specification.
Pre-treatmentConfirm cleaning, descaling, pickling, weld heat-tint removal and neutralization separately.
AcceptanceReference ASTM A967/A967M or another required standard revision and name the lot test and acceptance criterion.
DimensionsPassivation is not a plating process, but cleaning, pickling and electropolishing can affect the surface. Identify critical dimensions and threads.

PROCESS CONTROL

Clean → prepare → passivate → rinse → verify.

The sequence depends on the stainless grade, prior fabrication and customer specification. The steps below are a planning framework, not a universal recipe.

1 / Clean

Remove oil, shop soil and residues before the passivating treatment.

2 / Prepare

Review scale, weld heat tint and embedded iron. Descaling or pickling may be a separate operation.

3 / Passivate

Select nitric, citric or electrochemical treatment against the required standard and grade.

4 / Rinse & verify

Stop the chemistry with the specified rinse or neutralization, dry, inspect and record the lot result.

ASTM A967/A967M covers nitric, citric and electrochemical treatments and alternative effectiveness tests. ASTM A380/A380M covers cleaning, descaling, pickling and passivation practice.

Engineering details that change the result.

Welds and heat tint

State whether weld scale or heat tint must be removed before passivation. Passivation alone is not a substitute for required pickling or mechanical preparation.

Internal features

Identify blind holes, channels, threads and trapped-solution risks. Drainage, rinsing and drying access must be reviewed before processing.

Contamination control

Tell us about carbon-steel contact, blasting media, marking ink and prior processing. These can affect the cleanliness verification.

Post-treatment handling

Define packaging, gloves, clean assembly, lubricant and any subsequent welding or heat exposure.

Drawing note template for controlled work

Replace every bracketed field with approved project values before release.

DRAWING NOTE · EDIT THE BRACKETED FIELDS
PASSIVATE STAINLESS STEEL PER ASTM A967/A967M [REVISION], CHEMISTRY [NITRIC / CITRIC / ELECTROCHEMICAL].GRADE / CONDITION: [ ]. PRE-TREATMENT / PICKLING: [ ].SIGNIFICANT SURFACES, THREADS AND INTERNAL FEATURES: [ ].ACCEPTANCE TEST / LOT RECORDS: [ ]. PACKAGING AFTER TREATMENT: [ ].

Edit all bracketed fields before adding this note to a drawing.

Verification must match the order.

ASTM methods define possible tests; they do not automatically define your acceptance criterion or prove a processing facility is approved.

CharacteristicReferenceRFQ decision
Free iron / cleanlinessASTM A967/A967M alternative tests include water immersion, high humidity, salt spray, copper sulfate and ferricyanide-nitric acid tests.Name the selected test, lot sampling and pass/fail criterion.
Cleaning and scaleASTM A380/A380M practice for cleaning, descaling, pickling and passivation.State whether pickling or weld heat-tint removal is included.
Surface finishPassivation does not establish a roughness value or decorative appearance.Put Ra, visual sample and significant surfaces on the drawing when they matter.
ElectropolishingASTM B912 is a separate electropolishing passivation specification.Do not use “passivation” as a substitute for an electropolishing requirement.

ASTM A967/A967M-25 · ASTM A380/A380M-25 · ASTM B912-26. Verify the revision required by your contract.

YOUR NEXT STEP

Request a stainless-steel passivation quote.

Send the drawing, grade, prior operations, chemistry preference and inspection requirements.

Get a Quote ↗

Include with your inquiry

  • Grade, condition and quantity
  • Drawing and 3D model
  • Weld, heat-treatment and pickling history
  • Required chemistry and standard revision
  • Critical dimensions, threads and internal passages
  • Lot testing, records and packaging