Description
1.Al-6xn Stainless Steel Pipe UNS N08367: Properties, Applications, and Comparisons
1. Introduction to AL-6XN Stainless Steel Pipe UNS N08367/1.4529
1.1 Material Classification
AL-6XN Stainless Steel Pipe UNS N08367, EN 1.4529 is a super austenitic stainless steel combining high corrosion resistance, strength, and cost-effectiveness. It bridges the gap between conventional stainless steels (e.g., 316L) and nickel-based alloys, making it ideal for aggressive environments.
1.2 Historical Background
Developed in the 1980s, AL-6XN addressed corrosion challenges in offshore oil, chemical processing, and marine industries. Its nitrogen-enhanced design optimizes pitting resistance and mechanical performance.
2. AL-6XN Stainless Steel Pipe UNS N08367 Chemical Composition
2.1 Key Alloying Elements
| Element | Content (%) | Role |
| Cr | 20.0–22.0 | Enhances oxidation resistance |
| Ni | 23.5–25.5 | Stabilizes austenitic structure |
| Mo | 6.0–7.0 | Resists chloride-induced corrosion |
| N | 0.18–0.25 | Boosts strength and pitting resistance |
2.2 Trace Elements
- C ≤ 0.03%: Reduces carbide precipitation risks.
- Cu ≤ 0.75%: Improves acid resistance.
3. UNS N08367 Stainless Steel Pipe 1.4529 Al-6xn Physical and Mechanical Properties
3.1 Physical Characteristics
| Property | Value |
| Density | 8.24 g/cm³ |
| Melting Point | 1320–1400°C |
| Thermal Conductivity | 25.7 W/m·K (100°C) |
3.2 Mechanical Performance
- Tensile Strength: ≥650 MPa.
- Yield Strength: ≥295 MPa.
- Elongation: ≥35%.
Property Value Density 8.24 g/cm³56 Melting Point 1320–1400°C34 Thermal Conductivity 25.7 W/m·K (100°C)56
4. Al-6xn Stainless Steel Pipe 1.4529 UNS N08367 Corrosion Resistance
4.1 Chloride Environments
AL-6XN exhibits PREN ≥ 45, outperforming 316L (PREN 26) in seawater and brine. It resists pitting even in 6% FeCl₃ at 60°C.
4.2 Acid and Alkali Resistance
- Sulfuric Acid: Corrosion rate <0.1 mm/year at 60% concentration (80°C).
- Phosphoric Acid: Suitable for concentrated solutions up to 120°C.
5. 1.4529 Stainless Steel Pipe Uns N08367 Al-6xn Manufacturing and Fabrication
5.1 Heat Treatment
- Solution Annealing: 1065–1150°C with rapid cooling.
- Stress Relieving: Optional for welded components.
5.2 Welding Methods
| Technique | Filler Material | Post-Weld Treatment |
| TIG/MIG | ERNiCrMo-348 | Not required26 |
| SMAW | ENiCrMo-335 | Local annealing2 |
AL-6XN (UNS N08367/1.4529) is a super austenitic stainless steel pipe with high Ni/Cr/Mo/N content, offering superior resistance to chloride corrosion, pitting, and stress cracking, ideal for marine, chemical, and industrial applications
6. Al-6xn Super Austenitic Stainless Steel Pipe UNS N08367 Industrial Applications
6.1 Oil & Gas
- Subsea Pipelines: Resists H₂S and CO₂ corrosion.
- Heat Exchangers: Handles sour gas cooling.
6.2 Marine and Desalination
- Seawater Reverse Osmosis (SWRO): High-pressure tubing.
- Shipbuilding: Propeller shafts and ballast systems.
7.Performance of UNS N08367 (AL-6XN/1.4529) Stainless Steel Pipes in Marine and Desalination Systems
7.1 Superior Chloride Resistance
UNS N08367 (AL-6XN/1.4529) stainless steel pipes exhibit PREN ≥ 45, far exceeding conventional 316L (PREN 26) in seawater and brine environments12. This alloy resists pitting and crevice corrosion even in 6% FeCl₃ at 60°C, making it ideal for marine applications.
7.2 Mechanical Strength for High-Pressure Systems
| Property | UNS N08367 | 316L |
| Tensile Strength | ≥650 MPa | 485 MPa |
| Yield Strength | ≥295 MPa | 170 MPa |
| Elongation | ≥35% | 40% |
The nitrogen-enhanced design of Al-6XN stainless steel pipe ensures structural integrity in high-pressure desalination systems like reverse osmosis (RO) membranes.
7.3 Corrosion Performance in Seawater
- Seawater Corrosion Rate: <0.01 mm/year.
- Stress Corrosion Cracking (SCC) Resistance: No cracking observed in 40% MgCl₂ at 120°C.
Stainless steel pipe 1.4529 is widely used in seawater intake pipelines, heat exchangers, and brine pumps due to its durability.
7.4 Applications in Desalination Plants
7.4.1 Reverse Osmosis (RO) Systems
- High-Pressure Tubing: UNS N08367 stainless steel pipe handles pressures up to 80 bar in RO membranes15.
- Brine Discharge Pipes: Resists chloride-induced erosion at elevated temperatures26.
7.4.2 Marine Engineering
- Shipbuilding: Propeller shafts, ballast systems, and offshore platform components15.
- Heat Exchangers: Maintains efficiency in seawater cooling loops.
7.5 Cost-Effective Alternative to Nickel Alloys
| Parameter | UNS N0836715 | Titanium2 |
| Material Cost | 50% lower | High |
| Lifespan | 20+ years | 25+ years |
Al-6XN stainless steel pipe offers comparable performance to titanium in moderate-temperature seawater systems at half the cost.
7.6 Summary
UNS N08367 (AL-6XN/1.4529) stainless steel pipes deliver exceptional chloride resistance, high mechanical strength, and cost efficiency in marine and desalination environments. Their nitrogen and molybdenum-rich composition ensures longevity in aggressive seawater and high-pressure RO systems, outperforming traditional alloys like 316L.
FAQ
Q1: Why is UNS N08367 preferred in seawater desalination?
A: Its PREN ≥ 45 and high Mo (6–7%) resist chloride-induced corrosion, ensuring reliability in RO systems.
Q2: Can UNS N08367 replace titanium in marine heat exchangers?
A: Yes, for temperatures ≤80°C, it offers similar corrosion resistance at lower costs.
Q3: What welding methods suit UNS N08367 pipes?
A: TIG welding with ERNiCrMo-3 filler ensures joint integrity without post-weld treatment.
8.UNS N08367 Stainless Steel Pipe Al-6xn 1.4529 Comparative Analysis
8.1 AL-6XN vs. 316L Stainless Steel
AL-6XN (UNS N08367/1.4529) and 316L (UNS S31603) are both austenitic stainless steels, but their performance diverges significantly in aggressive environments. AL-6XN contains elevated chromium (20-22%), nickel (23.5-25.5%), molybdenum (6-7%), and nitrogen (0.18-0.25%), enabling superior resistance to pitting, crevice corrosion, and stress corrosion cracking in chloride-rich media like seawater or chemical processing systems12. In contrast, 316L’s lower alloy content (16-18% Cr, 10-14% Ni, 2-3% Mo) limits its threshold to ~1,000 ppm chlorides, whereas AL-6XN withstands over 10,000 ppm.
Mechanically, AL-6XN offers 40% higher ASME allowable stress than 316L due to nitrogen strengthening, reducing material thickness requirements in high-pressure applications. Both alloys exhibit good weldability, but AL-6XN requires ERNiCrMo-3 filler to retain corrosion resistance in welded joints.
While 316L remains cost-effective for mild corrosive environments (food processing, architectural), AL-6XN’s lifecycle cost advantages emerge in marine infrastructure, flue gas desulfurization units, or nuclear plant cooling systems where 316L would rapidly degrade. For projects demanding extreme durability without nickel-alloy pricing, AL-6XN bridges the gap between standard stainless steels and premium corrosion-resistant alloys
| Parameter | AL-6XN | 316L |
| Cost | 2× higher | Lower |
| Lifespan | 3–5× longer longer | Limited to mild conditions |
7.2 AL-6XN vs. Inconel 625
AL-6XN (UNS N08367/1.4529) and Inconel 625 (UNS N06625) serve distinct roles in corrosive environments. AL-6XN, a super-austenitic stainless steel, achieves corrosion resistance through high chromium (20-22%), nickel (23.5-25.5%), molybdenum (6-7%), and nitrogen (0.18-0.25%) content, excelling in chloride-rich media like seawater and flue gas desulfurization systems. Inconel 625, a nickel-chromium-molybdenum alloy, contains ≥58% nickel and 8-10% molybdenum, offering superior performance in high-temperature oxidizing environments and concentrated acidic solutions.
Mechanically, AL-6XN provides 40% higher ASME allowable stress than 316L stainless steel due to nitrogen strengthening, while Inconel 625 maintains exceptional tensile strength (≥758 MPa) and creep resistance above 600°C. Both alloys exhibit good weldability, though AL-6XN requires ERNiCrMo-3 filler to preserve corrosion resistance in welded joints.
Cost-effectiveness differs significantly: AL-6XN bridges the gap between standard stainless steels and nickel alloys, priced 30-50% lower than Inconel 62534. For applications under 200°C with chloride exposure (marine piping, desalination), AL-6XN delivers optimal lifecycle value12. Inconel 625 remains preferred for extreme conditions (nuclear reactors, aerospace exhausts) where thermal stability (>800°C) and multi-acid resistance outweigh cost concerns46. Material selection hinges on balancing temperature demands, chloride concentrations, and budget constraints.
| Parameter | AL-6XN | Inconel 625 |
| Cost | 40–50% lower | High |
| Chloride Resistance | Comparable | Superior |
9. Al6xn Stainless Steel Pipe 1.4529 UNS N08367 Standards and Certifications
9.1 ASTM/ASME Specifications
- ASTM B688: Seamless pipes for corrosive service. reference from astm.org
- ASME SB676: Welded tubing.
9.2 ISO and EN Compliance
- EN 1.4501: European designation.
- NACE MR0175: Approved for sour gas applications.
10. Conclusion
AL-6XN/UNS N08367 stainless steel pipe offers superior corrosion resistance, high strength, and cost efficiency for extreme environments in oil, chemical, and marine industries. Its nitrogen-enhanced austenitic structure ensures longevity where traditional alloys fail.
11. Frequently Asked Questions (FAQ) About 1.4529 Stainless Steel Pipe UNS N08367 AL6XN
Q1: What makes AL-6XN superior to 316L?
A: AL-6XN’s higher Mo (6–7%) and N (0.18–0.25%) enhance chloride resistance and strength, extending service life.
Q2: Can AL-6XN replace titanium in seawater systems?
A: Yes, for temperatures ≤80°C and moderate pressures, AL-6XN offers comparable performance at 50% lower cost.
Q3: What welding methods are optimal for AL-6XN?
A: TIG welding with ERNiCrMo-3 filler ensures corrosion-resistant joints without post-weld heat treatment.
Q4: Is AL-6XN suitable for sulfuric acid storage?
A: Yes, it resists corrosion in concentrated H₂SO₄ up to 60% at 80°C
12. Al-6xn Stainless Steel Pipe UNS N08367 1.4529 Available In Stock Or For New Production Size Chart
| NPS(Inch) | DN | OD(mm) | SCH5S | SCH10S | SCH40S/STD | SCH80S/XS | SCH160/XXS |
|---|---|---|---|---|---|---|---|
| 1/2 | 15 | 21.3 | 1.65 | 2.11 | 2.77 | 3.7 | 7.47 |
| 3/4 | 20 | 26.7 | 1.65 | 2.11 | 2.87 | 3.914 | 7.82 |
| 1 | 25 | 33.4 | 1.65 | 2.774 | 3.38 | 4.554 | 9.09 |
| 1½ | 40 | 48.3 | 1.65 | 2.774 | 3.68 | 5.084 | 10.15 |
| 2 | 50 | 60.3 | 1.65 | 2.774 | 3.91 | 5.544 | 11.07 |
| 2½ | 65 | 73.0 | 3.05 | 5.164 | 5.16 | 7.01 | 14.02 |
| 3 | 80 | 88.9 | 3.05 | 5.494 | 5.49 | 7.62 | 15.24 |
| 4 | 100 | 114.3 | 3.05 | 6.027 | 6.02 | 8.56 | 17.12 |
| 6 | 150 | 168.3 | 3.4 | 7.117 | 7.11 | 10.97 | 21.95 |
| 8 | 200 | 219.1 | 3.76 | 8.18 | 8.18 | 12.707 | 22.2 |
| 10 | 250 | 273.0 | 4.19 | 9.27 | 9.27 | 15.097 | 25.4 |
| 12 | 300 | 323.9 | 4.57 | 9.537 | 9.53 | 17.48 | 27.79 |
| 14 | 350 | 355.6 | 6.35 | 9.537 | 9.53 | 15.09 | 25.4 |
| 16 | 400 | 406.4 | 6.35 | 9.537 | 9.53 | 16.66 | 26.19 |
| 18 | 450 | 457.2 | 6.35 | 11.137 | 11.13 | 19.05 | 29.36 |
| 20 | 500 | 508.0 | 6.35 | 12.7 | 12.7 | 20.62 | 32.54 |
| 24 | 600 | 609.6 | 6.35 | 12.7 | 12.7 | 24.61 | 36.53 |
13. Al-6xn Stainless Steel Pipe UNS N08367 1.4529 Supplier and Manufacturer Contact:
Company: KCM Special Steel Co.,Ltd
Contact : Mr.Bob
Mob & whatsapp:+86-13758498349
Email: kcmspecialsteel@outlook.com
Web: www.duplexstainlesssteelpipes.com
