Sandvik 3R60™ Urea Grade – Premium ASTM 316L Alloy for Urea Industry

Typical urea plant applications of Sandvik 3R60™ Urea Grade are:

Urea specifications issued by: Stamicarbon, Snamprogetti, Urea Casale and Kellogg

Annealing after cold bending is not normally necessary, but the decision must be made after taking account of degree of bending and the operating conditions. Heat treatment, if any, should take the form of solution annealing, see under "Heat treatment".

The low ferrite and impurity contents of Sandvik 3R60 Urea Grade make it highly resistant to general and intergranular corrosion in the process solutions occurring in the manufacture of urea.

Sandvik 3R60 Urea Grade easily meets the Huey test and selective attack requirements specified by Stamicarbon, Snamprogetti and Urea Casale. The general corrosion rate is normally set at 0.6 mm/year maximum for unsensitized material (24mpy, 3.3um/48h).

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

Solution annealing: 1050-1100°C (1920-2010°F), 5-20 minutes, rapid cooling in water.

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

The mechanical machining of stainless steels always requires an adjustment to cutting to data and machining method to give satisfactory results. When turning is undertaken with carbide tipped tools, the cutting speed should be reduced by 30% for finish machining and 60% for rough machining, compared with the cutting speeds applied for AISI 316. Much the same applies to other operations. If high speed steel tools are used, approximately the same cutting speed can be used as for AISI 316.

Detailed recommendations for the choice of tools and cutting data are provided in brochure S-1,462-ENG. Select data as for grade 5R60 (AISI 316), taking into account the above comments.

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 3R60 U.G mainly:

Filler metals for welding: The sizes listed below are Sandvik stock standard. Local market stocks comprise sizes in common demand. Fortechnical information on the filler metal please refer to brochures S-2361-ENG, S-2362-ENG and S-2366-ENG.

The weldability of Sandvik 3R60 Urea grade 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 3R60 Urea grade, heat input of <1.5 kJ/mm and interpass temperature of <100°C (210°F) are recommended.

Recommended filler metals:

• TIG/GTAW or MIG/GMAW welding
  • 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)