AL-6XN (UNS N08367) and 254 SMO (UNS S31254) Price Sheets, Plates & Coils Supplier, Contact us to get price list, Sizes & Free Sample!
AL-6XN (UNS N08367) and 254 SMO (UNS S31254) are both high-molybdenum super austenitic stainless steels, widely used in harsh corrosive environments. Although the chemical composition and corrosion resistance of the two are similar, there are significant differences in key characteristics. HT PIPE is a N08367 and S31254 pipe supplier with 15+ export experience.
The chromium (~20%), molybdenum (~6%) and nitrogen (~0.2%) contents of the two are similar, but the nickel content is quite different. AL-6XN contains about 24% nickel, while 254 SMO contains only 18%.
Corrosion resistance AL-6XN and 254 SMO
The pitting resistance equivalent (PRE=Cr% + 3.3Mo% + 16N%) of the two is similar (AL-6XN about 42.7, 254 SMO about 42.2), but 254 SMO performs better in actual applications.
Welding of AL-6XN and 254 SMO
During welding, the molybdenum content of AL-6XN weld is about 4% (6% of the base material), and high-molybdenum welding materials (such as 9% molybdenum) are required to match the corrosion resistance. 254 SMO has a lower nickel content, so the welding process is more economical.
The yield strength ( Greater than or equal to 300 MPa) and tensile strength ( Greater than or equal to 650 MPa) of 254 SMO are slightly higher than those of AL-6XN (yield strength is about 290 MPa, and tensile strength is about 650 MPa). Both have higher elongation ( Greater than or equal to 40%), but AL-6XN has a higher cold work hardening rate due to its higher nitrogen content.
Standard coverage of AL-6XN and 254 SMO
254 SMO is included in European standards (EN 1.4547) and ASTM, while AL-6XN only meets ASTM standards and has not entered the EN system, which affects its application in the European market.
254 SMO has a low nickel content, and its price is less affected by nickel price fluctuations, which makes it more cost-effective.
AL-6XN: It is mainly used in seawater cooling systems, flue gas desulfurization (FGD) in coal-fired power plants, liquefied natural gas (LNG) storage tanks, etc., relying on its high nickel content and high temperature resistance.
254 SMO: It performs well in seawater desalination reverse osmosis membrane components, chemical reactors, and pulp bleaching equipment, especially in scenarios where roll forming is required (such as the flue of the absorption tower), which has more design flexibility.
