ATI Allegheny Ludlum AL-6XN® alloy (UNS N08367) is the most corrosion resistant iron-base austenitic stainless alloy produced by Allegheny Technologies at this time. 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 demonstrated 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 alternative 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 reqired to minimize life cycle costs in cer tain 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.

AL-6XN alloy is well suited for such applications as:

• Chemical process tanks and pipelines

• Process systems for offshore oil and gas platforms

• Condensers, heat exchangers and piping containing seawater or crude oil

• Filter washers, vats and press rolls in pulp bleaching plants

• Power plant flue gas scrubber environments

• Tall oil distillation columns and packing

• Desalination equipment and pumps

• Service water piping systems for nuclear power plants

• Transformer cases exposed to marine environments

• Pharmaceutical equipment (for product purity)

• Food processing equipment