Sandvik 3R65: Premium Molybdenum‑Alloyed Austenitic Stainless Steel

Sandvik 3R65 is used in a wide variety of industrial applications. Typical examples are heat exchangers, condensers, pipelines, cooling and heating coils in the chemical, petrochemical, pulp and paper and food industries.

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 3R65 has good resistance to:

Stress corrosion cracking: Austenitic steels are susceptible to stress corrosion cracking. Stress corrosion cracking may occur if the steel is simultaneously exposed to the following:

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 a chloride content that leads to both stress corrosion cracking and pitting.

In applications demanding high resistance to stress corrosion cracking, austenitic-ferritic steels, e.g. Sandvik SAF 2304 or SAF 2205 are recommended. See data sheets S-1871-ENG and S-1874-ENG.

Intergranular corrosion: Sandvik 3R65 has a low carbon content and therefore better resistance to intergranular corrosion than other steels of type AISI 316.

Pitting and crevice corrosion: Resistance of these types of corrosion improves with molybdenum content. Sandvik 3R65 has substantially higher resistance to attack than steels of type AISI 304.

Gas corrosion Sandvik 3R65 can be used in:

In flue gases containing sulphur, the corrosion resistance is reduced. In such environments Sandvik 3R65 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 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), 10-15 minutes, cooling in air.

Solution annealing: 1000-1100°C (1830-2010°F), 5-20 minutes, 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.

Sandvik 3R65 has good machining properties. Tool and cutting data recommendations are the same as for steel 3R60 in brochure S-1462-ENG.

Forms of supply:

Seamless tube and pipe in 3R65 is supplied in dimensions up to 260 mm outside diameter in the solution annealed and white-pickled condition or in the bright-annealed condition.

We can also deliver other product forms from stock in a grade corresponding to 316L mainly:

The weldability of Sandvik 3R65 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 3R65, heat input of <2.0 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 12 3 L / AWS A5.9 ER316L (e.g. Exaton 19.12.3.L)
• MMA/SMAW welding
  • ISO 3581 E 19 12 3 L R / AWS A5.4 E316L-17(e.g. Exaton 19.12.3.LR)
  • ISO 14343 S 19 12 3 L / AWS A5.9 ER316L (e.g. Exaton 19.12.3.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 Sandvik 3R65, is required.