Ultra 725LN
EN 1.4466, ASTM UNS S31050

General characteristics

High Ni and Mo austenitic grade with similar corrosion resistance to 904L. Typically used in Urea applications. Available as plate only.

Typical applications

  • Urea applications
  • Pulp & Paper industry
  • Flue gas cleaning
  • Chemical industry
  • Pharmaceutical industry


Product forms, available sizes and finishes


Product typeFinishesThicknessWidth
Quarto plateHot rolled white5,00-30,00≤ 3200
Chemical composition

The chemical composition may vary slightly between different product standards. The required standard will be fully met as specified on the order.

The chemical composition is given as % by weight.

TypicalUltra 725LN0.0125.
ASTM A240/A240MUNS S31050<0.020<224.0-26.020.5-23.51.60-2.600.09-0.15Si:<0.50 P:<0.030 S:<0.010
EN 10088-21.44660.05-0.15<216.0-19.06.0-9.5<0.80<0.10Si:<2 P:<0.045 S:<0.015
Mechanical properties

The mechanical properties of the available products are given in the table below.


StandardGradeRp0.2Rp1.0RmElongationImpact strengthRockwellHBHV
Product type: Hot rolled quarto plate
Typical (thickness 15 mm)Ultra 725LN28030063055

1)Elongation according to EN standard:
A80 for thickness below 3 mm.
A for thickness = 3 mm.
Elongation according to ASTM standard A2” or A50.

Corrosion resistance

For more information, see Outokumpu Corrosion Handbook.

Pitting corrosion resistanceCrevice corrosion resistance

PRE Pitting Resistant Equivalent calculated using the formula: PRE = %Cr + 3.3 x %Mo + 16 x %N
CPT Corrosion Pitting Temperature as measured in the Avesta Cell (ASTM G 150), in a 1M NaCl solution (35,000 ppm or mg/l chloride ions).
CCT Critical Crevice Corrosion Temperature is the critical crevice corrosion temperature which is obtained by laboratory tests according to ASTM G 48 Method F



Physical properties

Data according to EN 10088, EN 10095 or typical values.


DensityModulus of elasticityThermal exp. at 100 °CThermal conductivityThermal capacityElectrical resistanceMagnetizable

*) Austenitic stainless steel grades may be magnetizable to a certain degree after cold deformation, e.g. in temper rolled condition.



Outokumpu 725LN can be readily welded by a full range of conventional welding methods such as:
Shielded metal arc welding (SMAW)
Gas tungsten arc welding, TIG (GTAW)
Gas metal arc welding, MIG /MAG(GMAW)
Flux-cored arc welding (FCAW)
Plasma arc welding (PAW)
Submerged arc welding (SAW)

The steel is fully austenitic. For this reason, the sensitivity to hot cracking should be taken into account. MAG welding may  require modern pulse equipment and the use of special shielding gases containing Ar, He and O2/CO2.


Standards & approvals

The most commonly used international product standards are given in the table below.


ASTM A240/A240MUNS S31050
EN 10088-21.4466