{"id":3629,"date":"2026-09-16T11:10:53","date_gmt":"2026-09-16T08:10:53","guid":{"rendered":"https:\/\/www.defencemetal.com\/index.php\/en\/aisi-318\/"},"modified":"2026-09-25T21:15:00","modified_gmt":"2026-09-25T18:15:00","slug":"aisi-318","status":"publish","type":"page","link":"https:\/\/www.defencemetal.com\/index.php\/en\/aisi-318\/","title":{"rendered":"AISI 318 \/ (1.4462)"},"content":{"rendered":"

<\/p>\n

AISI 318 \/ (1.4462) \/ UNS S31803<\/h1>\n
DEFENCE METAL<\/span><\/p>\n
\n
AISI 318 (2205)<\/div>\n
UNS S32205 \u00b7 W.Nr. 1.4462 \u00b7 X2CrNiMoN22-5-3 \u00b7 in ASTM A240: 22.0-23.0% Cr \u2013 4.5-6.5% Ni \u2013 3.00-3.50% Mo \u2013 0.14-0.20% N \u2013 C \u2264 0.03% \u2013 balance Fe. A SECOND UNS NUMBER CARRIES THE SAME W.Nr.: S31803, whose band is wider (21.0-23.0% Cr \u2013 2.50-3.50% Mo \u2013 0.08-0.20% N) and which is NOT EQUIVALENT to S32205. It is a ferritic-austenitic (duplex) stainless steel; in the annealed condition the structure is roughly half ferrite and half austenite (Outokumpu: ‘a phase balance of approximately 50% ferrite and 50% austenite’; Rolled Alloys gives 40-50% ferrite in the annealed condition for 2205). It is NOT PRECIPITATION HARDENABLE, it is NOT AGED and it does not transform to martensite on cooling; its only heat treatment is solution annealing followed by a rapid quench.<\/div>\n
\n
Not to be confused with<\/div>\n

AISI 316L<\/a>AISI F53<\/a>AISI 329<\/a><\/div>\n<\/div>\n

\n
\n
For what<\/div>\n
It is bought where 316 and 316L cannot be used in chloride service because of stress corrosion cracking: chemical and petrochemical process equipment, structures and piping near seawater, pressure vessels, heat exchangers, flue gas desulphurisation plant.<\/div>\n<\/div>\n
\n
Forms<\/div>\n
Round bar \u00b7 Flat bar \u00b7 Plate \u00b7 Sheet \u00b7 Pipe and tube \u00b7 Forgings. All forms are supplied to order.<\/div>\n<\/div>\n
\n
Standards<\/div>\n
THERE IS NO AMS \u2014 no AMS number could be confirmed for this alloy; see ‘standart_notu’ for the detail. ASTM: A240 \/ SA-240 (plate, sheet and strip \u2014 S32205 and S31803) \u00b7 A276 \/ SA-276 (bar and shapes \u2014 S31803) \u00b7 A479 \/ SA-479 (bar and shapes) \u00b7 A182 \/ SA-182 (forged flanges and fittings \u2014 F60 for S32205, F51 for S31803) \u00b7 A789 \/ SA-789 (seamless and welded tube) \u00b7 A790 \/ SA-790 (seamless and welded pipe) \u00b7 A815 \/ SA-815 (wrought fittings) \u00b7 A923 (acceptance test for detecting detrimental intermetallic phase). EN: 1.4462 \u00b7 10088-2 \u00b7 10088-3. NORSOK MDS D45 (Langley Alloys). ASME Section IX welding group P-No 10H (Rolled Alloys, Langley Alloys).
S32205 AND S31803 ARE NOT EQUIVALENT, even though they carry the same W.Nr. (1.4462). IMOA states the difference: ‘The composition range that was originally set for 2205 (UNS S31803) was too broad.<\/span><\/div>\n<\/div>\n
\n
Advantage<\/div>\n
More than twice the yield strength of 316 in the same ASTM A240 table: 450 MPa against 205 MPa, and 655 MPa against 515 MPa in tension. Alongside that its PREN floor is 34.1 (formula %Cr + 3.3\u00d7%Mo + 16\u00d7%N, calculated from the bottom of the A240 composition band) against roughly 24 for 316.<\/div>\n<\/div>\n
\n
Welding<\/div>\n
FILLER METAL: AWS E2209 \/ ER2209 (Rolled Alloys: ‘2205 is welded with E2209 or ER2209 fillers’). The filler is enriched in nickel to hold the austenite balance; Industeel states the requirement as ‘Chemical composition has to be adapted to stabilize austenite’.<\/div>\n<\/div>\n
\n
Limits<\/div>\n
THE TEMPERATURE CEILING is about 300 \u00b0C and the reason is 475 \u00b0C embrittlement. IMOA: ‘The upper temperature limit for duplex stainless steel service is controlled by alpha prime formation.’ The ceilings, each with its source: the ASME limit IMOA gives for 2205 is 315 \u00b0C both unwelded and welded, the T\u00dcV limit 280 \u00b0C unwelded and 250 \u00b0C\u2026<\/div>\n<\/div>\n
REQUEST A QUOTE<\/a>All stainless steels →<\/a>TECHNICAL DETAILS ↓<\/span><\/div>\n
Compiled from manufacturer data sheets \u00b7 confirm against the current specification before ordering<\/div>\n<\/div>\n<\/div>\n

<\/p>\n