GOST 33259 09G2S Flanges GOST 33259-2015 Steel welded flat flange
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What is the 09G2S Flanges?
09G2S ( 09Г2С )
09G2S is a low-carbon, low-alloy structural steel used in the construction of welded structures.
Composition09G2S contains 0.09% carbon, a maximum of 2% manganese, a maximum of 1.0% silicon.
GOST 33259is a Russian standard for steel flanges, specifying design, dimensions, and technical requirements for use in various pressure pipelines and equipment. Flanges made from 09G2S low-alloy steel are widely used in oil & gas, power plants, and structural applications due to their high strength, weldability, and low-temperature resistance.
GOST 33259 Flange Types :
- Weld Neck (Type 01, 11) – For high-pressure pipelines.
- Slip-On (Type 02, 12) – Easier installation, used for moderate pressure.
- Blind (Type 05, 15) – Used to close pipelines or vessels.
- Socket Weld (Type 04, 14) – For small-diameter, high-pressure pipelines.
Material Composition of 09G2S (% Typical):
| Element | Composition (%) |
|---|---|
| Carbon (C) | 0.09 – 0.15 |
| Silicon (Si) | 0.50 – 0.80 |
| Manganese (Mn) | 1.30 – 1.60 |
| Sulfur (S) | ≤ 0.035 |
| Phosphorus (P) | ≤ 0.030 |
| Chromium (Cr) | ≤ 0.30 |
| Nickel (Ni) | ≤ 0.30 |
| Copper (Cu) | ≤ 0.30 |
Mechanical Properties:
| Property | Value |
|---|---|
| Yield Strength (MPa) | ≥ 345 |
| Tensile Strength (MPa) | 490 – 630 |
| Elongation (%) | ≥ 22 |
| Impact Toughness (J) | ≥ 34 (at -40°C) |
Applications of GOST 33259 09G2S Flanges
🔹 Oil & Gas Pipelines – High-pressure fluid transport.
🔹 Power Plants – Steam, water, and fuel handling systems.
🔹 Chemical & Petrochemical Plants – Corrosion-resistant applications.
🔹 Water & Wastewater Treatment – Structural and process piping.
Other Standards for Gost Flanges
GOST 33259 – Russian standard for steel pipe flanges
GOST 12821 – Weld neck flanges for pressure systems
GOST 12820 – Flat flanges for general applications
GOST 12822 – Blind flanges for pipeline sealing
