AL-6XN® Alloy
UNS N08367

The AL-6XN® alloy is a superaustenitic stainless steel which was developed by Allegheny Ludlum Corporation. It exhibits far greater resistance to chloride pitting, crevice corrosion and stress-corrosion cracking than exhibited by the standard 300 series stainless steels, and is less costly than the traditional nickel-base corrosion resistant alloys.

The AL-6XN alloy has exhibited good performance in a variety of highly corrosive environments. The AL-6XN alloy is available in a wide range of product forms including plate, strip, sheet, bar, billet, tubing, pipe, and castings. Its various product forms are covered by ASME and ASTM specifications. The use of wrought AL-6XN products in the ASME Boiler and Pressure Vessel is covered by Code Case 1997 (latest revision) for Section VIII construction and by Code Case N-438 (latest revision) for Section III construction. The use of AL-6XN castings is covered by Code Case 2106 (latest revision) for Section VIII and Code Case 497 (latest revision) for Section III construction. The alloy is approved for both welded and unwelded construction under ANSI/ASME B31.1 Code Case 155. Use of AL-6XN alloy in contact with hydrogen sulfide-containing petroleum and natural gas is covered by NACE MR0175-92. (Information provided by Allegheny Ludlum, Inc.)

ASME Boiler and Pressure Vessel Specifications
Sheet/ Plate Forgings Weld Fittings Rod and Bar Tubing - Welded/ Smls Pipe - Welded/ Smls Bolting- Bolts/ Nuts Filler Metals
SB688 SB462 SB366 SB691 SB676/ SB690 SB676/   SB690 SB649-AL-6XN/ SB649-AL-6XN ERNiCrMo-3 

ASME Boiler and Pressure Vessel Chemical Requirements for Sheet/Plate
Note: all percentages max unless otherwise specified
C Mn Si P S Cr Ni Mo N Fe Cu
0.03 2.00 1.00 0.04 0.03 20.00-22.00 23.50-25.50 6.00-7.00 0.18-0.25 Rem 0.75

ASME Boiler and Pressure Vessel Mechanical Properties for Sheet/Plate
Tensile Strength, Min ksi Yield Strength, (0.2% offset), Min, ksi Min. Elongation in 2", % Density lb/in³
95 45 30.0 0.291


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