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Hastelloy C-22 Stud Bolt
QS Fastener: Hastelloy C-22 Stud Bolt
Name: Hastelloy C-22 Stud Bolt
Material: Hastelloy C-22
Elongation: 40%
Standard: UNS N06022/2.4602
Size: 1.5 inch
Length: 200 mm
Feature:Good Anti-oxidation-reduction Performance
Application: For Chemicals and petrochemicals
Material: Hastelloy C-22
Elongation: 40%
Standard: UNS N06022/2.4602
Size: 1.5 inch
Length: 200 mm
Feature:Good Anti-oxidation-reduction Performance
Application: For Chemicals and petrochemicals
Quantity
Hastelloy C-22 Stud Bolt is manufactured from the high-performance alloy UNS N06022 (2.4602), offering exceptional elongation (up to 40%). Standard specifications include 1.5-inch diameter × 200 mm length, with custom production options available. Designed for extreme chemical/petrochemical applications, it delivers outstanding resistance to oxidation, reduction, and aggressive acid/mixed-media corrosion, making it the preferred fastener for critical environments like reactors and piping systems—ensuring long-term operational safety.
1. Pitting Resistance (ASTM G48 Method A) & Critical Pitting Temperature (CPT) Analysis
1.1 Test Standards & Methodology
- ASTM G48 Method A (Ferric Chloride Pitting Test)
- Test solution: 6% FeCl₃ + 1% HCl (pH≈1.3), temperature controlled to ±0.5℃
- Sample prep: 20×30×3 mm plate, polished to Ra≤0.8μm (eliminating machining effects)
- Failure criterion: CPT defined as the highest temperature with no visible pitting (20× magnification) after 24h
1.1 Test Standards & Methodology
- ASTM G48 Method A (Ferric Chloride Pitting Test)
- Test solution: 6% FeCl₃ + 1% HCl (pH≈1.3), temperature controlled to ±0.5℃
- Sample prep: 20×30×3 mm plate, polished to Ra≤0.8μm (eliminating machining effects)
- Failure criterion: CPT defined as the highest temperature with no visible pitting (20× magnification) after 24h
1.2 Performance Comparison
Hastelloy C-22 Stud Bolt demonstrates superior pitting resistance, with:
- CPT ≥85℃, significantly outperforming C-276 (~75℃)
- 72-hour test results:
- Weight loss <2.0 mg/cm², max pit depth ≤10μm (C-22)
- Weight loss 5.0-8.0 mg/cm², pit depth 30-50μm (C-276)
Hastelloy C-22 Stud Bolt demonstrates superior pitting resistance, with:
- CPT ≥85℃, significantly outperforming C-276 (~75℃)
- 72-hour test results:
- Weight loss <2.0 mg/cm², max pit depth ≤10μm (C-22)
- Weight loss 5.0-8.0 mg/cm², pit depth 30-50μm (C-276)
- Polarization curves in seawater (60℃):
- Breakdown potential (Eb) ≥800 mV vs. SCE
- Protection potential (Ep) gap (Eb-Ep) ≤50 mV, indicating excellent repassivation
- Breakdown potential (Eb) ≥800 mV vs. SCE
- Protection potential (Ep) gap (Eb-Ep) ≤50 mV, indicating excellent repassivation
1.3 Mechanism
The exceptional pitting resistance of Hastelloy C-22 Stud Bolt stems from:
- PREN (Pitting Resistance Equivalent Number) = 68 (Cr 22% + Mo 13% + W 3%) vs. C-276's 64
- XPS analysis: Passive film MoO₄²⁻/Cr₂O₃ ratio of 1.2:1, enhancing Cl⁻ repellency
The exceptional pitting resistance of Hastelloy C-22 Stud Bolt stems from:
- PREN (Pitting Resistance Equivalent Number) = 68 (Cr 22% + Mo 13% + W 3%) vs. C-276's 64
- XPS analysis: Passive film MoO₄²⁻/Cr₂O₃ ratio of 1.2:1, enhancing Cl⁻ repellency
2. Stress Corrosion Cracking (SCC) Resistance (NACE TM0177 Method A)
2.1 Test Conditions & Standards
- Standard: NACE TM0177-2016 Method A (constant load)
- Solution: 42% MgCl₂ saturated with H₂S (~2300 ppm), 120℃
- Stress: 90% AYS (Actual Yield Strength), 720h duration
2.1 Test Conditions & Standards
- Standard: NACE TM0177-2016 Method A (constant load)
- Solution: 42% MgCl₂ saturated with H₂S (~2300 ppm), 120℃
- Stress: 90% AYS (Actual Yield Strength), 720h duration
2.2 Performance Data
In harsh H₂S/MgCl₂ environments:
- Hastelloy C-22 Stud Bolt:
- No cracks at 100% AYS after 720h (ductile fracture morphology)
- Threshold stress intensity (KISCC) ≥45 MPa√m
- C-276: Intergranular cracks at 480–600h
- Inconel 625: Mixed-mode cracking <240h at 90% AYS
In harsh H₂S/MgCl₂ environments:
- Hastelloy C-22 Stud Bolt:
- No cracks at 100% AYS after 720h (ductile fracture morphology)
- Threshold stress intensity (KISCC) ≥45 MPa√m
- C-276: Intergranular cracks at 480–600h
- Inconel 625: Mixed-mode cracking <240h at 90% AYS
2.3 Key Advantages
1) Ultra-low grain boundary segregation (C≤0.015% + optimized heat treatment)
2). Mo/W enrichment at grain boundaries (≥25 at%), blocking hydrogen penetration
3) High dislocation density (5×10¹⁴ m⁻²), dispersing hydrogen accumulation
1) Ultra-low grain boundary segregation (C≤0.015% + optimized heat treatment)
2). Mo/W enrichment at grain boundaries (≥25 at%), blocking hydrogen penetration
3) High dislocation density (5×10¹⁴ m⁻²), dispersing hydrogen accumulation
3. Field Validation
3.1 Subsea Christmas Tree Bolts (GOM Oilfield)
- Environment: 1600m depth (19,000 ppm Cl⁻ + 500 ppm H₂S), 80℃
- Results:
- Hastelloy C-22 Stud Bolt: 5 years SCC-free
- Super 13Cr steel: Cracks within 6 months
3.1 Subsea Christmas Tree Bolts (GOM Oilfield)
- Environment: 1600m depth (19,000 ppm Cl⁻ + 500 ppm H₂S), 80℃
- Results:
- Hastelloy C-22 Stud Bolt: 5 years SCC-free
- Super 13Cr steel: Cracks within 6 months
3.2 Chemical Reactor Flange Connections
- Medium: 30% HCl + 2% FeCl₃, 60℃
- Results:
- M24 Hastelloy C-22 Stud Bolt: Preload loss <5% after 2000 pressure cycles, zero SCC
- Medium: 30% HCl + 2% FeCl₃, 60℃
- Results:
- M24 Hastelloy C-22 Stud Bolt: Preload loss <5% after 2000 pressure cycles, zero SCC
4. Material Selection Guidelines
- Opt for Hastelloy C-22 Stud Bolt when:
- Cl⁻ >10,000 ppm + H₂S >50 ppm (oil/gas)
- pH ≤2 mixed acids
- Cost-saving alternative: C-276 (non-critical areas) with ≥2mm corrosion allowance
- Opt for Hastelloy C-22 Stud Bolt when:
- Cl⁻ >10,000 ppm + H₂S >50 ppm (oil/gas)
- pH ≤2 mixed acids
- Cost-saving alternative: C-276 (non-critical areas) with ≥2mm corrosion allowance
Conclusion
With unmatched pitting resistance (CPT ≥85℃) and SCC resistance (KISCC ≥45 MPa√m), Hastelloy C-22 Stud Bolt is the ideal choice for extreme chemical, petrochemical, and subsea applications. Whether facing high chlorides, acidic media, or H₂S environments, it ensures long-term reliability and reduced maintenance costs.
With unmatched pitting resistance (CPT ≥85℃) and SCC resistance (KISCC ≥45 MPa√m), Hastelloy C-22 Stud Bolt is the ideal choice for extreme chemical, petrochemical, and subsea applications. Whether facing high chlorides, acidic media, or H₂S environments, it ensures long-term reliability and reduced maintenance costs.
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