Sandvik 5R10: High-Temperature Austenitic Chromium‑Nickel Steel for Superior Strength

Sandvik 5R10 is used for a wide range of industrial applications with emphasis on high temperature processes. Typical examples are: heat exchangers, condensers, pipelines, cooling and heating coils in the chemical, petrochemical, fertilizer, pulp and paper and nuclear power industries, as well as in the production of pharmaceuticals, foods and beverages.

Approvals: JIS Approval for Stainless Steel Tubes

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".

General corrosion: Sandvik 5R10 has good resistance in

The risk of general corrosion in sulfuric acid during shut down periods has to be taken into account. Since Sandvik 5R10 is not alloyed with molybdenum, the grade can only tolerate low concentrations at limited temperatures. In naturally aerated sulfuric acid the corrosion rate is below 0.1 mm/year provided the temperature is not higher than 20°C (68oF) in 5% solution.

Intergranular corrosion: Sandvik 5R10 has a relatively high carbon content. Thus, there is a certain risk of reduced intergranular corrosion resistance if the steel has become sensitized after e.g. improper heat treatment or welding. Sandvik 3R12 has a significantly lower carbon content and is therefore more safe regarding intergranular attack.

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 and the resistance improves with increasing molybdenum content.

Stress corrosion cracking: Austenitic steel is 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 lead 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.

Gas corrosion: Sandvik 5R10 can be use in

Creep behavior should also be taken into account when using the steel in the creep range. In flue gases containing sulfur, 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 oxidizing or reducing, i.e. the oxygen content, and whether impurities such as sodium and vanadium are present.

The tubes 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.

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

Forms of supply:

Tube and pipe are normally delivered in the solution annealed and white-pickled condition or in the bright-annealed condition. The size range can be seen from Fig. 1. U-tubes can be delivered on request.

The weldability of Sandvik 5R10 is good. Welding must be carried out without preheating and subsequent heat treatment is normally not required. 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.

For Sandvik 5R10, heat input of <1.5 kJ/mm and interpass temperature of <150°C (300°F) are recommended.

Recommended filler metals:

• TIG/GTAW or MIG/GMAW welding
  • ISO 14343 S 19 9 H / AWS A5.9 ER308H
• MMA/SMAW welding
  • ISO 3581 E 19 9 H R / AWS A5.4 E308H-17