{"id":3651,"date":"2026-09-16T11:14:21","date_gmt":"2026-09-16T08:14:21","guid":{"rendered":"https:\/\/www.defencemetal.com\/index.php\/en\/aisi-904l\/"},"modified":"2026-09-25T16:29:27","modified_gmt":"2026-09-25T13:29:27","slug":"aisi-904l","status":"publish","type":"page","link":"https:\/\/www.defencemetal.com\/index.php\/en\/aisi-904l\/","title":{"rendered":"AISI 904L \/ (1.4539)"},"content":{"rendered":"

<\/p>\n

AISI 904L \/ (1.4539) \/ UNS N08904<\/h1>\n
DEFENCE METAL<\/span><\/p>\n
\n
AISI 904L<\/div>\n
UNS N08904 \u00b7 W.Nr. 1.4539 \u00b7 X1NiCrMoCu25-20-5 \u00b7 ASTM A240 composition: 19.0-23.0% Cr \u2013 23.0-28.0% Ni \u2013 4.00-5.00% Mo \u2013 1.00-2.00% Cu \u2013 C \u2264 0.020% \u2013 N \u2264 0.10% \u2013 balance Fe. The EN 1.4539 band is narrower: 19.0-21.0% Cr \u2013 24.0-26.0% Ni \u2013 4.0-5.0% Mo \u2013 1.2-2.0% Cu. It is a SUPERAUSTENITIC stainless steel: produced by SOLUTION ANNEALING + RAPID COOLING, NOT PRECIPITATION HARDENABLE and not aged; strength is raised only by COLD WORK.<\/div>\n
\n
Not to be confused with<\/div>\n

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

\n
\n
For what<\/div>\n
Bought for process equipment where reducing acids and warm chloride environments occur together: sulphuric and phosphoric acid service, pulp and paper, refineries, fertiliser plants, acid pickling lines, seawater-wetted equipment.<\/div>\n<\/div>\n
\n
Forms<\/div>\n
Round bar \u00b7 flat bar \u00b7 plate \u00b7 sheet \u00b7 pipe and tube \u00b7 forging. All forms supplied to order.<\/div>\n<\/div>\n
\n
Standards<\/div>\n
THERE IS NO AMS \u2014 no AMS number for N08904 could be confirmed in any independent source. ASTM: A240 \/ SA-240 (plate, sheet, strip) \u00b7 A276 (bar and shapes) \u00b7 A479 \/ SA-479 (bar and shapes for boilers and pressure vessels) \u00b7 A182 \/ SA-182 (forged flanges, fittings and valve parts, F904L) \u00b7 A312 \/ SA-312 (seamless and welded pipe). EN: 10088-2, 10088-3, 10272. Also NACE MR0175.
1) N08904 HAS BEEN MOVED FROM THE B-SERIES TO THE A-SERIES. N08904 IS NO LONGER in the current grade lists of the nickel-alloy B-series standards: the scope of ASTM B649 is N08925, N08024, N08026, N08031, N08354, N08926, N08936 and R20033 (HT Pipe and\u2026<\/span><\/div>\n<\/div>\n
\n
Advantage<\/div>\n
Resistance to reducing acids, and the COPPER behind it. The 1-2% copper addition makes 904L suitable for sulphuric and phosphoric acid service under reducing conditions; this is a mechanism separate from molybdenum or chromium.<\/div>\n<\/div>\n
\n
Welding<\/div>\n
It is weldable. Filler metal: Sandmeyer gives the ’20 25 CuL’ covered electrode and wire; thyssenkrupp states that TIG, MAG, arc, laser beam and submerged arc welding are suitable;<\/div>\n<\/div>\n
\n
Limits<\/div>\n
1) DO NOT EXPECT STRENGTH. In ASTM A479 the tensile minimum of 904L, 490 MPa, is BELOW that of 304 and 316 in the same table (515 MPa); its yield minimum of 220 MPa is 15 MPa above theirs. 904L is not a strength material but a corrosion material.<\/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