ASTM A380 Complete Guide
Standard Practice for Cleaning, Descaling & Passivation of Stainless Steel Parts, Equipment and Systems
The definitive engineering reference for preparing stainless steel surfaces. From contamination prevention through final verification—field-proven procedures refined over 10+ years and 200+ facility commissionings.
What is ASTM A380?
ASTM A380 is the foundational standard practice that establishes procedures for cleaning, descaling, and passivation of stainless steel parts, equipment, and systems. Unlike A967 (which focuses solely on passivation), A380 addresses the complete lifecycle of surface preparation.
The standard recognizes that effective passivation requires proper surface preparation. Contamination, oils, scale, and foreign material must be removed before passivation chemicals can effectively contact and treat the stainless steel surface.
Contamination Sources & Prevention
Identifies common contaminants during fabrication, handling, and installation
Mechanical & Chemical Cleaning Methods
Detailed procedures for both approaches with selection guidance
Descaling & Pickling Procedures
Removal of heat tint, oxide scale, and weld discoloration
Verification & Testing Methods
Copper sulfate, ferroxyl, and other acceptance testing procedures
Cleaning Methods per ASTM A380
A380 classifies cleaning methods into mechanical and chemical approaches, each with specific applications and limitations
✓ Acceptable Mechanical Methods
⚠️ Prohibited Methods
Alkaline Cleaning
Removes oils, greases, and organic soils. First step in most cleaning sequences.
Solvent Cleaning
For heavy oils, machining fluids, and stubborn organic contamination.
Emulsion Cleaning
Water-based cleaners with surfactants for mixed contamination types.
Descaling & Pickling Procedures
Descaling removes oxide scale, heat tint, and welding discoloration that would otherwise prevent proper passivation
Understanding Heat Tint
Descaling Methods
HNO₃/HF gel applied directly to welds. Most common for localized treatment.
Full immersion in nitric-hydrofluoric solution for parts and small equipment.
Electric current-assisted descaling for precision applications.
Complete Descaling → Passivation Sequence
Contamination Sources & Prevention
A380 extensively addresses contamination prevention—recognizing that avoiding contamination is more efficient than removing it
Iron Contamination
The most critical contamination type. Free iron embedded in stainless steel surfaces will rust, compromising corrosion resistance.
- Carbon steel tools/brushes
- Mixed grinding wheels
- Steel shot blasting
- Contact during handling
- Contaminated fabrication equipment
Organic Contamination
Oils and greases prevent acid solutions from contacting the metal surface, resulting in incomplete passivation.
- Cutting fluids and machining oils
- Fingerprints (skin oils)
- Lubricants and greases
- Drawing compounds
- Protective coatings
Particulate Contamination
Debris and particles can become trapped under the passive layer or block acid access to the surface.
- Weld spatter and slag
- Grinding debris
- Dust and airborne particles
- Packaging materials
- Construction debris
A380 Prevention Best Practices
Mark and segregate stainless-only tools. Never use on carbon steel.
Use clean gloves. Avoid bare-hand contact with finished surfaces.
Separate from carbon steel. Cover to prevent airborne contamination.
Identify contamination before processing. Test suspect areas.
Passivation Procedures in A380
While ASTM A967 provides detailed passivation specifications, A380 establishes the foundational principles and integrates passivation into the complete cleaning workflow.
A380 Passivation Fundamentals
Traditional method using 20-50% nitric acid. Fast acting, effective on heavily contaminated surfaces.
Typical: 20-25% HNO₃ at 120-150°F for 20-30 minutesSafer alternative with excellent iron removal. Chelation mechanism protects welds. Preferred for pharmaceutical and food-grade.
Typical: 4-10% citric at 140-160°F for 30-60 minutesSee our comprehensive ASTM A967 Guide for detailed passivation chemistries, temperature/time parameters, and acceptance testing. Also explore our Citric vs Nitric Comparison.
A380 Passivation Requirements
Verification & Testing Methods
A380 provides guidance on testing to verify successful cleaning and passivation
Copper Sulfate Test
Most common field verification method
- Apply copper sulfate solution to cleaned surface
- Wait 6 minutes (keep surface wet)
- Rinse with DI water
- Inspect for copper (pink/red) deposits
Ferroxyl Test
Highly sensitive iron detection
- Apply ferroxyl solution to cleaned surface
- Observe immediately (30-60 seconds)
- Look for blue spots indicating iron
- Rinse thoroughly after testing
Water Break Test
Visual cleanliness verification
- Rinse surface with DI water
- Observe water drainage pattern
- Look for continuous sheeting vs. beading
High Humidity Test
Accelerated corrosion verification
- Place samples in humidity cabinet
- Maintain 95%+ RH at 100°F for 24-48 hrs
- Remove and inspect for rust/staining
ASTM A380 vs ASTM A967
Understanding when to reference each standard—and how they work together
📋 When to Use A380
- Developing overall cleaning procedures
- Addressing contamination prevention
- Specifying descaling/pickling requirements
- New construction commissioning guidance
- Training fabrication personnel
- General surface preparation reference
📋 When to Use A967
- Specifying exact passivation chemistry
- Defining temperature/time parameters
- Selecting verification test methods
- Creating passivation work instructions
- Quality control documentation
- Customer specification compliance
| Aspect | ASTM A380 | ASTM A967 |
|---|---|---|
| Full Title | Standard Practice for Cleaning, Descaling, and Passivation | Standard Specification for Chemical Passivation Treatments |
| Primary Focus | Complete surface preparation workflow | Chemical passivation procedures specifically |
| Scope | Cleaning + Descaling + Passivation | Passivation only |
| Chemistry Details | General guidance | Specific formulations with temperature/time |
| Contamination Prevention | Extensive coverage | Limited coverage |
| Testing Methods | Overview provided | Detailed test procedures (Practice A-F) |
| Best For | Overall process guidance, new construction | Specifying passivation requirements |
CXP Delivers A380-Compliant Results
After 10+ years implementing ASTM A380 across 200+ facilities—from pharmaceutical plants to aerospace manufacturing—CXP has refined procedures that consistently deliver specification-compliant outcomes.
Related Technical Resources
Continue building your passivation knowledge with these expert guides and tools
Need ASTM A380-Compliant Cleaning & Passivation?
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