Sandvik 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.
- ASTM A213 and A312
- EN 10216-5
- SEW 400 (Feb 1991)
Sandvik 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 Sandvik 2RE10.
- ASME Code Case 2591. Section VIII, Division 1.
Chemical composition (nominal) %
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
- Welding wire and wire electrodes
- Covered electrodes
- Sheet and plate
- Bar steel (grade Sandvik 2RE69)
|Proof strength||Tensile strength||Elong.||Hardness|
1 MPa = 1 N/mm2
|Proof strength||Tensile strength||Elong.||Hardness|
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
Due to its austenitic microstructure, Sandvik 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
Density: 7.9 g/cm3, 0.29 lb/in3
|Temperature, °C||W/m °C||Temperature, °F||Btu/ft h °F|
|Temperature, °C||J/kg °C||Temperature, °F||Btu/lb °F|
|Temperature, °C||Per °C||Temperature, °F||Per °F|
1) Mean values in temperature ranges (x10-6)
|Temperature, °C||μΩm||Temperature, °F||μΩin.|
|Temperature, °C||MPa||Temperature, °F||ksi|
Sandvik 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 Sandvik 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.
Sandvik 3R12 is the Sandvik 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.
Stress corrosion cracking (SCC)
The higher nickel content makes Sandvik 2RE10 slightly more resistant to stress corrosion cracking (SCC) than conventional austenitic stainless steels, such as ASTM 304L.
Sandvik 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 Sandvik 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 Sandvik 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.
Sandvik 2RE10 has considerably higher pitting corrosion resistance than ASTM 304L and is also superior to ASTM 329, as illustrated by figure 4.
Tubes are delivered in the heat treated condition. If another heat treatment is needed, due to further processing, the following is recommended.
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.
1000–1100°C (1830–2010°F), 5–20 minutes, rapid cooling in air or water.
The weldability of Sandvik 2RE10 is good. No preheating is required. Suitable methods of fusion welding are manual metal-arc welding (MMA) with covered electrodes and gas shielded arc welding, with the TIG and MIG methods as first choice.
Welding should be undertaken with a low heat input, i.e. high travel speed and low current. The general recommendation for fully austenitic stainless steels is a heat input of 1.0 kJ/mm maximum and an interpass temperature not exceeding 150°C (302oF). The diameter of electrodes used in manual metal-arc welding should be 2.5 mm (3/32 in.) max. for wall thicknesses up to 6 mm (1/4 in.), and 3.25 mm (1/8 in.) max. for larger wall thicknesses. A stringer bead welding technique shall be used.
In common with all austenitic stainless steels, Sandvik 2RE10 has low thermal conductivity and high thermal expansion. Welding should therefore be carefully planned in advance so that distortion of the welded joint can be minimised. If, despite these precautions, it is believed that residual stresses may impair the function of the weldment, it is recommended that the entire structure is stress relieved. See under 'Heat treatment'.
The welding of fully austenitic steels usually involves the risk of hot cracking in the weld metal, particularly if the weldment is under constraint. As a result of its very high purity, however, Sandvik 2RE10 is not especially susceptible to this kind of cracking.
We recommend Sandvik 25.20.L as the filler metal for gas shielded arc welding. For manual metal-arc welding, covered electrode Sandvik 25.22.2.LMnB is recommended. Sandvik 25.22.2.LMn welding wire and Sandvik 25.22.2.LMn welding strip are recommended for overlay welding of tube sheets in cases where corrosion resistance equal to that of Sandvik 2RE10 is required.
* Contact us for information about this covered electrode.
The excellent formability of Sandvik 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'.
Sandvik 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 Sandvik 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 Sandvik 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 Sandvik 2RE10 the service life will be substantially longer than, for example, ASTM 304L.