Super Stainless Steel AL-6XN (UNS N08367)
AL-6XN is a "super-austenitic" stainless steel with a high molybdenum content, designed to provide exceptional resistance to pitting, crevice corrosion, and chloride-induced stress corrosion cracking. Developed as an evolution of the 300-series, it contains a robust blend of 6% Molybdenum, 20% Chromium, and 24% Nickel, further strengthened by Nitrogen. This chemistry grants the alloy a Pitting Resistance Equivalent Number (PREN) of approximately 44, allowing it to thrive in environments that would destroy standard 316L or even 904L stainless steels.
At Aries Alloys, we supply AL-6XN to the most demanding maritime and chemical sectors. It is the gold standard for high-chloride process streams where the reliability of a nickel-base alloy is required but the budget demands a more economical iron-base solution.
Elite Corrosion Performance
- Chloride Pitting Mastery: The 6% molybdenum content provides world-class protection against localized attack in stagnant or high-salinity waters.
- Immunity to SCC: With a high nickel content of 24%, AL-6XN is virtually immune to chloride stress corrosion cracking, a frequent cause of failure in the 300-series.
- Nitrogen Strengthening: The addition of nitrogen (0.18-0.25%) increases yield strength by nearly 50% compared to standard austenitic steels while enhancing pitting resistance.
- Acid Resistance: Offers excellent durability in various acidic environments, particularly in dilute sulfuric and phosphoric acids.
- Intergranular Corrosion Defense: Its extra-low carbon content ensures that the material remains stable after welding, preventing sensitization.
Technical Profile & Composition
The Super-Austenitic Advantage:
AL-6XN bridges the gap between stainless steel and nickel-base superalloys. Unlike many other high-performance alloys, it retains the excellent ductility and ease of fabrication found in the 300-series while offering the corrosion resistance of much more expensive materials.
Mechanical & Physical Data:
- Density: 8.06 g/cm^3
- Yield Strength: ≥ 45,000 psi (310 MPa)
- Magnetic Property: Non-magnetic in all conditions.
- ASME Approval: Approved for use in pressure vessels and heat exchangers for temperatures up to 800°F.
Primary Industrial Use Cases
Aries Alloys provides AL-6XN for mission-critical infrastructure:
- Desalination Plants: High-pressure reverse osmosis piping, pump components, and brine heaters.
- Offshore Oil & Gas: Seawater piping systems, firewalls, and subsea control lines.
- Chemical Processing: Equipment for the production of herbicides, fertilizers, and chlorinated organic compounds.
- Power Generation: Flue gas desulfurization (FGD) scrubbers and steam condenser tubing.
- Pharmaceutical & Biotech: Clean-steam systems and high-purity process vessels where sanitation and corrosion resistance are vital.
Product Availability at Aries Alloys
We stock and supply AL-6XN in accordance with ASTM A240, B688, and B675:
- Plates & Sheets: Large-gauge plates for the fabrication of tanks, scrubbers, and pressure vessels.
- Seamless & Welded Pipes: High-durability piping for seawater intake and chemical transport.
- Round & Hex Bars: Precision rods for machining high-strength, acid-resistant shafts and fasteners.
- Forged Fittings: Custom flanges and elbows designed for high-integrity connectivity.