A mid-ranged corrosion resistant 6Mo alloy with good strength
- Good corrosion resistance to moderate acids & sea-water
- 50% stronger than stainless steel
- Usable temperature limit of 1000°F
- AL6XN Chemistry & Specifications
- Features & benefits of AL6XN weld studs
- How an AL6XN arc weld stud works
- AL6XN Datasheet
AL6XN weld studs are available in a variety of fastener styles for manual (MIG, TIG) arc and capacitor discharge welding methods. These weld studs provide a secure, cross-sectional weld in single-sided access situations for salt water corrosion resistance, as well as general mid-range corrosion protection. Also considered a 6Moly alloy, AL6XN is similar in chemistry and capabilities to Alloy 926 and SMO 254. AL6XN weld studs are a low carbon, high purity, nitrogen-bearing "super-austenitic" stainless alloy. With a higher nickel and molybdenum content than Duplex 2205 and Super Duplex 2507, these studs deliver better corrosion resistance while giving a more cost effective alternative to nickel super alloys like Inconel or Hastelloy in moderately corrosive conditions.
• Moderate general corrosion resistance
• Excellent chloride / salt water protection
• Good performance in phosphoric acid
• Moderate resistance to nitric acid
In chemical processes which utilize chlorides, such as paper mills and waste water, stress corrosion cracking (SCC) is a common culprit for 316L stainless failures. Duplex alloys will outlast environments that will cause SCC in 316 stainless, but for more severe low PH environments, weld studs made from higher nickel content alloys like AL6XN will generally work better. For the most extreme situations, alloys with >45% nickel content like Hastelloy are often considered.
Outstanding Resistance to Salt Water
Seawater is where AL6XN weld studs outperform so many alloys providing protection to stress corrosion cracking, pitting and crevice corrosion in a broad range of marine applications. AL6XN weld studs contain a minimum of 6% molybdenum content and it is this addition of molybdenum that provides the greatest protection against pitting and crevice corrosion.
Mechanical Properties of Nickel Alloy AL6XN
Electrical Resistivity: 535 Ohm-circ mil/ft
Ultimate Tensile Strength: 108 ksi
0.2% Yield Strength: 53 ksi
Density: 0.291 lb/in 3
• High molybdenum content provides enhanced corrosion protection in chloride environments.
• Carbon helps to prevent sensitization during welding
• Chromium enhances pitting and crevice corrosion resistance
• The interstitial strengthening effect of nitrogen gives AL6XN weld studs good high strength properties
• Desalination plants depend on AL6XN weld studs for the salt water corrosion protection
• Pulp bleaching equipment and piping
• The power industry uses AL6XN weld studs where salt water and chlorides are present such as steam surface condensers, supercritical, high pressure, feed water heaters, steam surface condensers, flue-gas desulfurization equipment and in nuclear power water piping
• Chemical Processing - processing tanks, vessels and pipes as well as plate and frame heat exchangers.
Resources: AL6XN Torque Specs
AL6XN weld studs are an ideal way to securely attached fasteners in extreme applications where reaching both sides of a structure is impossible or undesired. These weld studs can be attached by a variety of welding techniques, such as MIG or TIG welding or they can be attached by automated welding guns using Arc or Capacitor Discharge (CD) technologies.
Arc and Capacitive Discharge (CD) Weld Stud Benefits
- Security: Unlike the peripheral weld used on a common bolt, the weld used to secure a weld stud fastener is a full cross sectional weld, so the full face of the fastener is welded in place for a strong, secure hold. And since there are no drilled holes – which weakens the structural integrity of the application – the attachment is even stronger.
- Speed: Installing an AL6XN weld stud is a fast and simple process with a most fasteners taking less than 1 second to weld in place. Plus there is no secondary work such as drilling, polishing or grinding.
- Simplicity: Weld studs require almost no special skills and minimal training and equipment is needed for installation. In addition, the equipment is also portable.
- Variety: AL6XN weld studs are available in a wide variety of fastener styles including (but not limited to) fully threaded, partially threaded, full base, reduced base, long, tapped base, and shoulder thread to name a few.
AL6XN Specifications: UNS N08367, ASTM A 240, ASTM B 688, ASME SA-240, ASME SB-688, ASTM B690, ASTM B691, ASTM A240, ASTM B688, ASME SA-240, ASME SB-688