Datasheet updated

2023-11-29 08:40
(supersedes all previous editions)

Alleima® 2RE10 is an austenitic stainless steel with extremely low carbon and impurity contents. The grade is characterized by:

  • Excellent resistance to corrosion in nitric acid
  • Excellent resistance to intergranular corrosion
  • Good resistance to pitting
  • Good weldability


  • UNS: S31002
  • EN Number: 1.4335
  • W.Nr.: 1.4335*
  • DIN: X 1 CrNi 25 21*

* Obsolete. Replaced by EN.

Product standards

  • ASTM A213 and A312
  • EN 10216-5
  • SEW 400 (Feb 1991)

Alleima® 2RE10 conforms to EN no. 1.4335, but actual composition specified for EN no. 1.4335 allows considerable higher maximum levels of C, Si, P, S and Mo. High levels of these elements increase the potential for corrosion and have therefore been kept as low as possible in Alleima® 2RE10.


  • ASME Code Case 2591. Section VIII, Division 1.

Chemical composition (nominal)

Chemical composition (nominal) %
C Si Mn P S Cr Ni Mo
≤0.015 ≤0.15 1.8 ≤0.020 ≤0.005 24.5 20 ≤0.10


Alleima® 2RE10 is very suitable for heat exchanger tube and pipe in processes that treat nitric acid, for example, the manufacture of nitric acid, acrylic fibres, ammonium nitrate and the reprocessing of nuclear reactor fuel. Extensive practical experience in such applications has confirmed the superiority of Alleima® 2RE10 over standard steels such as ASTM 304L and ASTM 329.

Tail gas preheaters

The main reason for highly corrosive conditions in tail gas preheaters is that droplets of nitric acid are entrained in the tail gas from the absorption tower. When this gas enters the heater, the droplets settle on the hot tube wall and start boiling. The temperature of the heating medium, usually hot process gas or steam, can be very high. In this type of condition, ASTM 304L tends to have a short service life. Tubes and tube sheets manufactured in Alleima® 2RE10 are recommended for a long service life


In cooler/condensers, corrosion is normally encountered at the inlet end, where the first condensate is formed. If reboiling of the first condensate occurs, the corrosive conditions become very severe, leading to the kind of attack illustrated in figure 5. This typical corrosion problem can be detected easily. By upgrading to Alleima® 2RE10 the service life will be substantially longer than, for example, ASTM 304L.

Corrosion resistance

General corrosion

Alleima® 2RE10 was developed to combat corrosion problems in nitric acid service. Thanks to its high chromium and low impurity contents it has considerably better resistance to nitric acid than steels of type ASTM 304L, as illustrated by the isocorrosion diagram, figure 1. In such applications Alleima® 2RE10 is far superior to ASTM 304L, ASTM 321 and ASTM 329. The corrosion rates of these grades in 65% nitric acid (Huey test) are compared in figure 2.

Alleima® 3R12 is the Alleima version of ASTM 304L. Results are presented from tests of solution annealed material (the delivery condition) and also material in a sensitized (650°C (1202oF) for 1 h condition. ASTM 329 was sensitized at 650°C (1202oF ) for only 5 min.

Figure1. Isocorrosion diagram for Alleima® 2RE10 and 3R12 (ASTM304L) in a naturally aerated, stagnant solution of nitric acid. The curves represent a corrosion rate of 0.1 mm/year (4 mpy).

Figure 2. Huey test results for different stainless steels (average values). Allows denote accelerated attack for each period, which indicates material will not perform satisfactorily in service.

Stress corrosion cracking (SCC)

The higher nickel content makes Alleima® 2RE10 slightly more resistant to stress corrosion cracking (SCC) than conventional austenitic stainless steels, such as ASTM 304L.

Intergranular corrosion

Alleima® 2RE10 is highly resistant to intergranular corrosion even after long-term sensitization. Figure 3 shows the results of Huey testing (boiling in 65% nitric acid for 5x48 h) sensitized specimens of Alleima® 2RE10 and a steel of type ASTM 304L. The low tendency for sensitization is an advantage in complicated welding operations.

In delivery testing, by means of the Huey test, the guaranteed maximum corrosion rate for Alleima® 2RE10 is 0.12 mm/year (5 mpy) in the solution annealed condition, and 0.20 mm/year (8 mpy) after sensitization at 675°C (1250°F). Even lower values can be guaranteed by agreement in certain cases. Figure 3 demonstrates that sensitization does not increase the corrosion rate greatly in Huey testing, whereas the corrosion rate for ASTM 304L increases significantly.

Pitting corrosion

Alleima® 2RE10 has considerably higher pitting corrosion resistance than ASTM 304L and is also superior to ASTM 329, as illustrated by figure 4.

Figure 3. Corrosion curves for Alleima® 2RE10 and AISI 304L obtained from Huey testing after sensitization at 675°C (1250°F).

Figure 4. Critical pitting temperature (CPT) for Alleima® 2RE10, ASTM 304L and ASTM 329 in neutral chloride solutions (potentiostatic determination at +300mV SCE).


The excellent formability of Alleima® 2RE10 permits cold bending to very small bending radii. Cold working does not impair resistance to general and intergranular corrosion. Annealing is not normally necessary after cold bending. If, however, tubes have been cold worked and are to be used under conditions where stress corrosion cracking (SCC) is liable to occur, stress relieving is recommended. See under 'Heat treatment'.

Forms of supply

Tube and pipe are supplied in dimensions up to 80 mm (3.15 in.) outside diameter in the solution annealed and white-pickled or in the bright annealed condition.

Other forms of supply

  • Covered electrodes
  • Sheet and plate
  • Bar steel (grade Sandvik 2RE69)

Heat treatment

Tubes are delivered in the heat treated condition. If another heat treatment is needed, due to further processing, the following is recommended.

Stress relieving

850–950°C (1560–1740°F), 10–15 minutes, rapid cooling in air. Alternatively 1000–1050°C (1830–1920°F), about 1 minute, rapid cooling in air.

Solution annealing

1000–1100°C (1830–2010°F), 5–20 minutes, rapid cooling in air or water.

Mechanical properties

Metric units, at 20°C
Proof strength Tensile strength Elong. Hardness
Rp0.2a) Rp1.0a) Rm Ab)
MPa MPa MPa % Vickers
≥205 ≥210 ≥500-670 ≥35c) 155

1 MPa = 1 N/mm2

Imperial units, at 68°F
Proof strength Tensile strength Elong. Hardness
Rp0.2a) Rp1.0a) Rm A2"
ksi ksi ksi % Vickers
≥30 ≥31 ≥73-98 ≥35c) 155

a) R p0.2 and R p1.0 correspond to 0.2% offset yield strength respectively.
b) Based on L0 = 5.65√S0 , where L0 is the original gauge length and S0 the original cross-section area.
c) EN 10216-5 with min 45% can be fulfilled

Impact strength

Due to its austenitic microstructure, Alleima® 2RE10 has very good impact strength both at room temperature and at cryogenic temperatures.

Tests have demonstrated that the steel fulfils requirements according to the European standards EN 13445-2 (UFPV-2) ( (min. 60 J (44 ft-lb) at -270oC (-455oF)) and EN 10216-5 (min. 60 J (44 ft-lb) at -196oC (-320oF).

At high temperatures

Metric units
Proof strength
Tensile strength
Rp0.2 Rp1.0 Rm
°C MPa MPa MPa
min. min. min.
50 195 225 485
100 180 210 470
150 170 200 455
200 160 190 440
250 150 180 430
300 145 170 420
350 140 165 415
Imperial units
Proof strength
Tensile strength
Rp0.2 Rp1.0 Rm
°F ksi ksi ksi
min. min. min.
200 36.4 30.8 68.5
400 23.1 27.4 63.7
600 20.8 24.4 60.7

Physical properties

Density: 7.9 g/cm3, 0.29 lb/in3

Thermal conductivity
Temperature, °C W/m °C Temperature, °F Btu/ft h °F
20 13 68 7.5
100 15 200 8.5
200 17 400 10
300 19 600 11.5
400 21 800 12.5
500 23 1000 13.5
600 25 1200 14.5
700 26 1300 15
Specific heat capacity
Temperature, °C J/kg °C Temperature, °F Btu/lb °F
20 470 68 0.11
100 495 200 0.12
200 530 400 0.13
300 555 600 0.13
400 580 800 0.14
500 600 1000 0.15
600 615 1200 0.15
700 630 1300 0.15
Thermal expansion1)
Temperature, °C Per °C Temperature, °F Per °F
30-100 15.5 86-200 8.5
30-200 16.5 86-400 9
30-300 17 86-600 9.5
30-400 17 86-800 9.5
30-500 17.5 86-1000 9.5
30-600 17.5 86-1200 10
30-700 18 86-1400 10

1) Mean values in temperature ranges (x10-6)

Temperature, °C μΩm Temperature, °F μΩin.
20 0.84 68 33.1
100 0.90 200 35.2
200 0.98 400 35.6
300 1.07 600 42.3
400 1.10 800 43.7
500 1.14 1000 45.5
600 1.18 1200 46.8
700 1.20 1400 47.7
800 1.22 1600 48.3
900 1.23 1800 48.7
1000 1.24 - -
Modulus of elasticity1)
Temperature, °C MPa Temperature, °F ksi
20 195 68 28.3
100 190 200 27.6
200 182 400 26.4
300 174 600 25.1
400 166 800 23.8
500 158 1000 22.5

1) (x103)


The weldability of Sandvik 2RE10 is good. Suitable methods of fusion welding are manual metal-arc welding (MMA/SMAW) and gas-shielded arc welding, with the TIG/GTAW method as first choice.

In common with all fully austenitic stainless steels, Sandvik 2RE10 has low thermal conductivity and high thermal expansion. Welding plans should therefore be carefully selected in advance, so that distortions of the welded joint are minimized. If residual stresses are a concern, solution annealing can be performed after welding.

For Alleima® 2RE10, heat-input of <1.0 kJ/mm and interpass temperature of <100°C (210°F) are recommended. A string bead welding technique should be used.

Recommended filler metals

TIG/GTAW or MIG/GMAW welding

25.20.L (e.g. Exaton 25.20.L)

ISO 14343 S 25 22 2 N L (e.g. Exaton 25.22.2.LMn)

MMA/SMAW welding

ISO 3581 E 25 22 2 N L B (e.g. Exaton 25.22.2.LMnB)

ISO 14343 S 25 22 2 N L wire or strip electrodes are recommended for overlay welding of tube sheets and high-pressure vessels in cases where corrosion resistance, equal to that of Alleima® 2RE10, is required.


Disclaimer: Recommendations are for guidance only, and the suitability of a material for a specific application can be confirmed only when we know the actual service conditions. Continuous development may necessitate changes in technical data without notice. This datasheet is only valid for Alleima materials.