What is the difference between 316L and 316L urea grade?
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What is 316L urea-grade stainless steel?
316L urea-grade stainless steel (often labeled 316LUG or 316LMod) is a specialized, low-carbon, "modified" austenitic stainless steel (similar to 1.4435) designed specifically for urea production environments. It offers superior corrosion resistance in urea-carbonate solutions, achieved through higher molybdenum (2.5–3.0%) and lower silicon (<0.5%) content compared to standard 316L.
What is 316L stainless steel?
316L stainless steel is a low-carbon, austenitic (non-magnetic) marine-grade alloy renowned for high corrosion resistance, durability, and excellent weldability. With a maximum carbon content of 0.03%, it minimizes chromium carbide precipitation during welding, making it superior to 316 for preventing corrosion in welded components.
What is the difference between 316L and 316L urea grade?
316L Urea Grade (UG) is a "customized upgraded" version of standard 316L stainless steel specifically designed for urea production environments, featuring lower silicon, higher molybdenum, and strictly controlled, very low ferrite content (maximum 0.5–0.6%). While standard 316L offers general corrosion resistance, 316L UG provides superior resistance to hot urea-carbonate solutions, preventing intergranular corrosion in urea stripping units.
316L VS.316L urea grade:Chemical Composition Comparison (wt%)
| Element | Standard 316L (ASME SA240) | 316L Urea Grade (UG) |
| Carbon (C) |
≤ 0.030% |
≤ 0.020% |
| Chromium (Cr) | 16.0% – 18.0% | 17.0% – 18.5% |
| Nickel (Ni) | 10.0% – 14.0% | 13.0% – 15.0% |
| Molybdenum (Mo) | 2.0% – 3.0% | 2.2% – 3.0% |
| Silicon (Si) |
≤ 0.75% |
≤ 0.40% |
| Manganese (Mn) |
≤ 2.00% |
≤ 2.00% |
| Phosphorus (P) |
≤ 0.045% |
≤ 0.025% |
| Sulfur (S) |
≤ 0.030% |
≤0.010% |
| Nitrogen (N) |
≤ 0.10% |
≤ 0.10% |
316L VS.316L urea grade:Mechanical Properties
| Property | Standard 316L (ASME SA240) | 316L Urea Grade (UG) |
| Tensile Strength |
≥ 485 MPa (70 ksi) |
≥ 490 - 515 MPa |
| Yield Strength (0.2%) |
≥ 170 MPa (25 ksi) |
≥ 190 - 205 MPa |
| Elongation (in 50mm) |
≥ 40% |
≥ 45% |
| Hardness (Brinell) |
≤ 217 HBW |
≤ 200 HBW |
| Ferrite Content | Not strictly limited |
≤0.6% (or FN ≤1) |
| Microstructure | Austenite + Delta Ferrite | Fully Austenitic |
| Huey Test Corrosion Rate | N/A |
≤0.6 mm/year |
316L vs. 316L Urea Grade: Corrosion Resistance
Standard 316L cannot pass the mandatory tests required for the Urea Grade. The Urea Grade must pass the Huey Test (consisting of five 48-hour cycles in boiling nitric acid, with a corrosion rate of ≤ 3.3 μm/48h) and a selective corrosion test to verify its resistance to corrosion in highly corrosive ammonium carbamate media.
What welding procedures are required for 316L urea grade?
Welding procedures for 316L Urea Grade (often modified as 316L UG or 25-22-2) require strict control to maintain corrosion resistance in urea-carbamate environments. Key procedures include TIG (GTAW) or MIG (GMAW) welding, with low-heat input (<1.5 kJ/mm) and an interpass temperature below 100°C (210°F), ensuring minimal ferrite and no carbide precipitation.
316L vs. 316L Urea Grade: cost
316L Urea Grade (UG) is generally more expensive than standard 316L stainless steel, often featuring a price premium due to stricter production standards and tighter chemical composition controls. While standard 316L is suitable for general corrosion resistance, 316L UG is a "customized" version designed for high-stress urea production environments.
316L vs. 316L Urea Grade: Applications
316L: Suitable for general corrosive environments, such as food processing, pharmaceutical equipment, mild marine engineering, and general chemical industries. Its corrosion resistance is sufficient to handle most routine industrial applications.
316L Urea Grade: Specifically designed for the extremely harsh environments involved in urea production. It is utilized in equipment subjected to high pressures (140–250 atm), high temperatures (180–210°C), and highly corrosive ammonium carbamate media. Typical applications include core components such as urea synthesis towers, high-pressure separators, high-pressure piping, stripping towers, high-pressure condensers, and scrubbers.
316LUG Stainless Steel Supplier
If you have project-specific requirements for 316L or 316LUG stainless steel, we invite you to place an order. GNEE maintains a substantial inventory of popular products for you to choose from. These materials can be processed into a wide variety of practical forms-including plates, coils, tubes, bars, wires, and more. For detailed information regarding chemical composition or to request free samples, please contact our factory immediately. We offer competitive pricing and exceptional service.
Available Product Forms for 316L / 316LUG Stainless Steel
| Product Form | Typical Dimensions / Size Range | Common Standards (ASTM/ASME) |
| Hot Rolled Plate |
Thickness: 6mm – 150mm Width: Up to 3000mm |
ASTM A240 / SA240 |
| Cold Rolled Sheet | Thickness: 0.3mm – 6.0mm | ASTM A240 / SA240 |
| Seamless Pipe |
OD: 6mm – 610mm Sch 5S to Sch XXS |
ASTM A312 / SA312 |
| Welded Pipe | OD: 150mm – 2000mm | ASTM A358 / SA358 |
| Seamless Tube |
OD: 12.7mm – 50.8mm WT: 1.0mm – 3.5mm |
ASTM A213 / SA213 |
| Forgings / Flanges |
DN15 – DN1200 Class 150 to Class 2500 |
ASTM A182 / SA182 |
| Round Bar | Diameter: 5mm – 500mm | ASTM A276 / A479 |
| Fittings | Elbows, Tees, Reducers | ASTM A403 / SA403 |
| Welding Consumables | Spools, Rods, Electrodes | AWS A5.9 / A5.4 |
