We are now stocking ASTM A182 / A276 / A479 ASME SA182 / SA276 / SA479 Grade F44 / UNS S31254 / 1.4547 EN 10088-3 / 6Mo / 6 Mo / 6% Mo certified to Norsok MDS R17 M630 / M650 / Nace MR 01 03 / MR 01 75 / ANSI ISO 15156 / ASTM G48 method A / EN ISO 3651 – 2A / ASTM A262 Practice E / PED 97/23/EC / ASTM A388 / API 6A PSL3 PSL4. This super austenitic material is NACE and NORSOK approved and has a PREN (pitting resistance equivalent number - an empirical relationship to predict the pitting resistance of austenitic and duplex stainless steels) of 42 to 45. "Super austenitic” grades have enhanced pitting and crevice corrosion resistance compared with the ordinary austenitic or duplex types. This is due to the further additions of chromium 20%, molybdenum 6 to 6.5%, and nickel 18% and is enhanced with the addition of Nitrogen 0.2%. It also conforms, or is similar to, ASTM A182 / A276 / A479 ASME SA182 / SA276 / SA479 Grade F44 / UNS S31254 / 1.4547 EN 10088-3 / 6Mo / 6 Mo / 6% Mo certified to Norsok MDS R17 M630 / M650 / Nace MR 01 03 / MR 01 75 / ANSI ISO 15156 / ASTM G48 method A / EN ISO 3651 – 2A / ASTM A262 Practice E / PED 97/23/EC / ASTM A388 / API 6A PSL3 PSL4. X1CrNiMoN20-18-7 / X1CrNiMoCuN20-18-7 / Afnor Z1 CNDU 20.18.06 AZ / SS2378 / SS 2378 / Brands 254SMO / 6Mo / 6MOLY / Norsok M630-MDS R17 BAR / M630-MDS R14 FORGINGS / M630-MDS R15 PLATE / 1.4529 / AL6XN / AL6XN PLUS / ALLOY 926 / ALLOY SSC-6MO / INCOLOY 25-6 HN / INCOLOY 25-6 MO / NAS 254 NM / NAS 255 NM / UNS N08367 / UNS N08926 (Formerly N08925) / URANUS B25. 

EN 1.4547 – 254SMO® is an austenitic stainless steel which due to its high molybdenum content possesses very high resistance to pitting and crevice corrosion. The steel grade was developed for use in halide-containing environments such as seawater. EN 1.4547 also shows good resistance to uniform corrosion and, especially in acids containing halides, this steel grade is superior to conventional stainless steel. Due to its high nitrogen content EN 1.4547 has higher mechanical strength than most other austenitic stainless steels. It is non-magnetic in the annealed condition but may become slightly magnetic as a result of cold-working or welding. Corrosion resistance - Uniform corrosion: The high content of alloy materials gives the steel exceptionally good resistance to uniform corrosion. Acids and acid solutions containing halide ions are very aggressive and EN 1.4547 is preferable to use. Examples of such acids are hydrochloric acid, hydrofluoric acid, chloride contaminated sulphuric acid, phosphoric acid and pickling acids based on nitric acid and hydrofluoric acid solutions. Intercrystalline corrosion: EN 1.4547 has a very low carbon content. This means that there is very little risk of carbide precipitation in connection with heating. On the other hand there is a risk of precipitation of intermetallic phases in the temperature range 600-1000° C. These precipitations do not involve a risk of intercrystalline corrosion in the corrosive media where this steel is used. Thus welding can be carried out without risk of intercrystalline corrosion. Stress corrosion cracking: Conventional steels of the 1.4301 and 1.4401 type are sensitive to stress corrosion cracking (SCC) under certain conditions, i.e. a special environment in combination with tensile stress in the material and often also an elevated temperature. Resistance to SCC increases with the increased content of nickel and molybdenum. This implies that the high-alloyed EN 1.4547 has very good resistance to SCC. Pitting and crevice corrosion: Resistance to pitting corrosion and crevice corrosion is determined mainly by the content of chromium, molybdenum and nitrogen in the material. This is often illustrated by using the pitting resistance equivalent (PRE) for the material, which can be calculated using the formula PRE = %Cr + 3.3 x %Mo + 16 x %N.