What is 316L UG stainless steel?

What is 316L UG stainless steel?

316L UG (Urea Grade) is a specialized, low-carbon "modified" variant of 316L stainless steel, specifically engineered for urea production environments (i.e., urea-carbamate solution environments). It typically maintains a fully austenitic microstructure with extremely low ferrite content (≤ 0.5%–0.6%) to effectively prevent intergranular corrosion. It is specifically designated for critical equipment within urea production plants (such as high-pressure strippers and heat exchangers).

 

What is the equivalent material for SS 316L UG?

316L Urea Grade (UG) stainless steel (commonly designated as 316LUG or 316LMod) is specifically engineered to provide high corrosion resistance in urea-carbonate environments. Its closest direct equivalent is EN 1.4435 also known as modified 316L UG steel and in specific application scenarios, this material outperforms standard 316L stainless steel.

 

Are 1.4435 and 316L UG the same thing?

1.4435 is a stainless steel grade defined under European Standards (EN). Although its chemical composition aligns more closely with the requirements for Urea Grade (UG) applications than that of standard 316L (1.4404), not all 1.4435 material can be designated as 316L UG.

 

SS 316L UG Chemical Composition

Element	316L UG (Typical wt. %)
Carbon (C)	≤ 0.020
Manganese (Mn)	≤ 2.00
Silicon (Si)	≤ 0.40
Phosphorus (P)	≤ 0.020
Sulfur (S)	≤ 0.010
Chromium (Cr)	17.0 – 18.5
Nickel (Ni)	13.0 – 15.0
Molybdenum (Mo)	2.20 – 3.00
Nitrogen (N)	0.10 – 0.16
Iron (Fe)	Balance

 

Mechanical Properties (at Room Temperature)

Property	Metric Value	Imperial Value
Tensile Strength, min.	485 MPa	70 ksi
Yield Strength (0.2%), min.	190 MPa	27.5 ksi
Elongation (L0=50mm), min.	40%	40%
Hardness (Brinell), max.	190 HBW	-
Hardness (Rockwell B), max.	90 HRB	-

 

Corrosion Resistance of 316L UG Stainless Steel

The corrosion resistance of 316L UG (Urea Grade) stainless steel is specifically engineered with strictly controlled ferrite content maintained at a level of ≤ 0.6% (typically ≤ 0.5%) thereby ensuring the formation of a fully austenitic microstructure that effectively prevents intergranular and selective corrosion. It is designed to withstand the extremely harsh operating conditions encountered during urea production, environments in which standard 316L stainless steel would typically fail.

 

What is the difference between 316L and 316L urea grade?

316L Urea Grade (316L UG / 316Lmod) is a specialized, "custom-upgraded" variant of standard 316L stainless steel, engineered specifically to meet the extreme corrosion resistance requirements of urea production environments. It distinguishes itself from standard 316L through a lower silicon content (< 0.5%), a higher molybdenum content (> 2.5%), and an extremely low and strictly controlled ferrite content (< 0.5%), all designed to effectively prevent urea-carbonate corrosion.

 

What precautions should be taken when welding 316L UG?

It is essential to select matching urea-grade welding consumables (such as modified ER316L or specialized urea-grade welding electrodes) to ensure that the ferrite content of the weld metal is similarly controlled. Heat input must be strictly controlled to prevent the precipitation of intermetallic phases (such as the Sigma phase), thereby avoiding any reduction in corrosion resistance.

 

What are the common equipment applications for 316L UG?

High-Pressure Systems (HP Loop) specifically designed for the urea industry:
Liners for Urea Reactors.
High-Pressure Condensers.
High-Pressure Strippers.
High-Pressure Scrubbers.

 

316LUG Stainless Steel  pipe Supplier

GNEE provides 316L UG (Urea Grade) stainless steel pipes that fully comply with international standards, including ASTM A312 (for seamless pipes), ASTM A213 (for heat exchanger tubes), and EN 10216-5. We offer complete traceability with EN 10204 3.1 or 3.2 certificates, including third-party inspections by renowned agencies such as BV, TUV, and Lloyd's.

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Product Type	Specification/Standard	Size Range (Typical)
Instrumentation Tubing	ASTM A269 / EN 10216-5	OD: 6.0 - 25.4 mm; WT: 0.5 - 2.11 mm
Heat Exchanger Tubes	ASTM A213 / ASME SA213	OD: 12.7 - 38.1 mm; WT: 1.0 - 3.5 mm
Process Piping (Seamless)	ASTM A312 / ASME SA312	NPS: 1/2" - 12"; Schedule: 10S, 40S, 80S, XXS
High Pressure Pipes	Manufacturer Standard	OD: Up to 250 mm; WT: Up to 40 mm

 

 In addition to standard wall thickness seamless pipes, GNEE offers thin-walled heat exchanger/instrumentation tubing as well as large-diameter heavy-wall pipes. Furthermore, we provide a 'one-stop' solution by supplying matching 316L UG elbows, tees, flanges, and welding consumables, effectively eliminating the risk of material mismatch between different system components.