- 316L Mod
The UREA 316L grade has been specially developed for urea plant applications. It is a 316L modified stainless steel with extra – low silicon content and substantial higher molybdenum contents. The low carbon content, combined with a well balanced chemistry (low silicon and nickel content close to 14%) makes the alloy fully austenitic, free of intermetallic phase precipitations. The ferrite level is kept under 0.5% in the solution annealing and water quenched conditions. The UREA 316L grade is designed for the fabrication of lining interiors in urea units for improved corrosion resistance properties in urea – carbonate environments or complementary products (pipes, fittings…). The alloy is not designed for nitric acid application.
|Yield strength 0,2% :||200||≥ N/mm²|
|Hardness HB30:||215||≤ HB|
at 1120 – 1180°C (2048 – 2156°F) followed by water quenching.
Typical maximum corrosion results required following different specifications after Huey tests (ASTM A262 C – five periods of 48 h.) are:
- maximum weight loss lower than 3,3 μm/48 h (130 mg/dm² per 24 h.)
- maximum depth for microcracks of 200 μm in the long direction and 70 μm in the transverse direction.
- Ferrite check 100% (less than 0,5%)
- Measurement location chosen by Inspector
Welding The UREA 316L grade can be welded with most of the welding processes: TIG, Plasma, MIG welding, as well as SMAW, SAW or FCAW processes. The alloy is sensitive to hot cracking phenomenon due to its fully austenitic microstructure. Weld should be performed in order to obtain extra – low ferrite contents, no carbide or nitrides precipitations, low silicon contents as well as no intermetallic phases precipitations. Higher manganese content products should be considered.