Sandvik 304L (Plate and sheet)

Chemical composition (nominal) %

Forms of supply-finishes and dimensions

Plate & sheet

Plate & sheet are delivered in the solution annealed and pickled condition.

Sheet may be supplied as annealed and pickled, polished or in the bright-annealed condition

The size ranges available are given below in Sizes in stock section.

Mechanical properties

1 MPa = 1 N/mm²
a) R_p0.2 and R_p1.0 correspond to 0.2% offset and 1.0% offset yield strength, respectively.
b) Based on L₀ = 5.65 ÖS₀ where L₀ is the original gauge length and S₀ the original cross-section area.

The hardness 201(Brinell) 92 (Rockwell B)

The impact strength (Charpy V) at -60 °C (-75 °F) is min. 150 J (110 ft-lb).

At high temperatures

Physical properties

1) x10³

Corrosion resistance

General corrosion

Sandvik 304L has good resistance in

Sandvik 304L has better resistance than normal type AISI 304 to oxidising agents, such as nitric acid. Figure 2 shows isocorrosion in nitric acid for Sandvik 304L.

Figure 2. Diagram showing isocorosion in nitric acid for Sandvik 304L at the corrosion rates of 0.1 mm/year (4mpy) and 0.3 mm/year (12 mpy).

Intergranular corrosion

Sandvik 304L has a low carbon content and therefore better resistance to intergranular corrosion than steels of type AISI 304.

The TTC-diagram, Figure 3, which shows the result of testing for 24 hour in boiling Strauss solution (12% sulphuric acid, 6% copper sulphate) confirms the superior resistance of Sandvik 304L. This is an advantage in complicated welding operations.

The good resistance against intergranular attack of Sandvik 304L is also demonstrated in the Huey test (boiling in 65% nitric acid for 5x48h). A maximum corrosion rate of 0.40 mm/year in the annealed condition and 0.60 mm/year in the sensitised (675°C) condition can be met.

Sandvik 304L with its controlled and low impurity level, shows better results than ordinary AISI 304 or 321.

Figure 3. TTC-diagram for Sandvik 3R12 (AISI 304L) and AISI 304.

Pitting and crevice corrosion

The steel may be sensitive to pitting and crevice corrosion even in solutions of relatively low chloride content. Molybdenum-alloyed steels have better resistance improves with increasing molybdenum content.

Stress corrosion cracking

Austenitic steels are susceptible to stress corrosion cracking. This may occur at temperatures above about 60°C (140°F) if the steel is subjected to tensile stresses and at the same time comes into contact with certain solutions, particularly those containing chlorides. Such service conditions should therefore be avoided. Conditions when plants are shut down must also be considered, as the condensates which are then formed can develop conditions that leads to both stress corrosion cracking and pitting.

In applications demanding high resistance to stress corrosion cracking we recommend the austenitic-ferritic steel Sandvik SAF 2304. See data sheet S-1871-ENG.

Gas corrosion

Sandvik 304L can be used in

Creep behaviour should also be taken into account when using the steel in the creep range.

In flue gases containing sulphur, the corrosion resistance is reduced. In such environments the steel can be used at temperatures up to 600-750°C (1110-1380°F) depending on service conditions. Factors to consider are whether the atmosphere is oxidising or reducing, i.e. the oxygen content, and whether impurities such as sodium and vanadium are present.

Heat treatment

Plates are normally delivered in heat treated condition. If additional heat treatment is needed after further processing the following is recommended.

Stress relieving

850-950°C (1560-1740°F), cooling in air.

Solution annealing

1000-1100°C (1830-2010°F), rapid cooling in air or water.

Welding

The weldability of Sandvik 304L is good. Suitable welding methods are manual metal-arc welding with covered electrodes and gas-shielded arc welding with the TIG and MIG methods as first choice. Preheating and post-weld heat treatment are not normally necessary.

Since the material has low thermal conductivity and high thermal expansion, welding must be carried out with a low heat input and with welding plans well thought out in advance so that the deformation of the welded joint can be kept under control. If, despite these precautions, it is foreseen that the residual stresses might impair the function of the weldment, we recommend that the entire structure be stress relieved. See under Heat treatment.

As filler material for gas-shielded arc welding we recommend wire electrodes and rods Sandvik 19.9.L or 19.9.LSi. In manual metal-arc welding covered electrodes Sandvik 19.9.LR or 19.9.LRHD are recommended. If flux cored arc welding is preferred, electrodes Sandvik 19.9.LT or 19.9.LVT should be used.

Bending

Annealing after cold bending is not normally necessary, but this point must be decided with regard to the degree of bending and the operating conditions. Heat treatment, if any, should take the form of stress relieving or solution annealing, see under heat treatment.

Hot bending is carried out at 1100-850°C (2010-1560°F) and should be followed by solution annealing.

Applications

Sandvik 304L is used for a wide range of industrial applications. Typical examples are: Tanks and reactors in the chemical, petrochemical, fertilizer, pulp and paper and nuclear power industries, as well as in the production of pharmaceuticals, foods and beverages.