Overview
AL6XN is a superaustenitic stainless steel with outstanding resistance to chloride pitting, crevice corrosion and stress corrosion cracking. It is a low carbon, high purity, nitrogen-bearing"super-austenitic"stainless alloy. The AL-6XN alloy was designed to be a seawater resistant material and has since been demonstr ated to be resistant to a broad range of very corrosive environments. It is readily available from stock in a wide range of product forms, including thick plate that is suitable for multi-pass welding during field fabrication.
The high strength and corrosion resistance of the AL-6XN alloy make it a better choice than the conventional duplex stainless steels and a cost effective alter native to more expensive nickel-base alloys in applications where excellent formability, weldability, strength and corrosion resistance are essential. It is also a cost-effective alternative to less expensive alloys, such as Type 316, that do not have the strength or corrosion resistance required to minimize life cycle costs in certain applications.
The high nickel and molybdenum contents provide improved resistance to chloride stress-corrosion cracking. Copper (Cu) has been intentionally kept to a residual level for improved performance in seawater40. The high alloy composition of the AL-6XN alloy resists crevice corrosion and pitting in oxidizing chloride solutions to a degree previously achieved only by nickel-base alloys and titanium.
Specification
ASTM B366/B366M Standard Specification for Factory-Made Wrought Nickel and Nickel Alloy Fittings.
Chemical Composition
Ni | Cr | Mo | C | N | Mn | Si | P | S | Cu | Fe |
23.5-25.5 | 20.00-22.00 | 6.00-7.00 | 0.03 Max | 0.18-0.25 | 2.0 Max | 1.00 Max | .040 Max | 0.03 Max | 0.75 Max | Remainder |
Mechanical Properties
Temp. °F (°C) | Ult. Tensile Strength, psi | .2% Yield Strength, psi | Elongation in 2”, percent | Charpy V-Notch Toughness, ft-lb |
-450 (-268) | 218,000 | 142,000 | 36 | 353* |
-320 (-196) | 196,000 | 107,000 | 49 | 85 |
-200 (-129) | - | - | - | 100 |
70 (21) | 108,000 | 53,000 | 47 | 140 |
200 (93) | 99,900 | 49,400 | 47 | - |
400 (204) | 903,000 | 40,400 | 46 | - |
600 (316) | 86,000 | 36,300 | 47 | - |
800 (427) | 87,000 | 36,000 | 48 | - |
