Haihao Group Delivers GOST 33259 St20 Weld Neck Flanges for Azerbaijan Pipeline Project
Haihao Group has successfully completed the production and shipment of a batch of GOST 33259 St20 weld neck flanges for a pipeline project in Azerbaijan. The order includes multiple sizes from DN50 to DN300, covering PN16 and PN40 pressure ratings, all manufactured from St20 carbon steel in accordance with the GOST 33259 standard.
To satisfy the customer’s project specifications, Haihao Group carefully controlled the chemical composition of the St20 material throughout production. Every flange was manufactured with precise machining, dimensional inspection, and complete quality verification before shipment, ensuring dependable performance in industrial piping systems.
Shipment Overview
The shipment includes the following products:
| Product | Size | Material | Standard |
| Weld Neck Flange, Raised Face | DN50 × PN16 | St20 | GOST 33259 |
| Weld Neck Flange, Raised Face | DN50 × PN40 | St20 | GOST 33259 |
| Weld Neck Flange, Raised Face | DN80 × PN16 | St20 | GOST 33259 |
| Weld Neck Flange, Raised Face | DN80 × PN40 | St20 | GOST 33259 |
| Weld Neck Flange, Raised Face | DN100 × PN16 | St20 | GOST 33259 |
| Weld Neck Flange, Raised Face | DN100 × PN40 | St20 | GOST 33259 |
| Weld Neck Flange, Raised Face | DN150 × PN16 | St20 | GOST 33259 |
| Weld Neck Flange, Raised Face | DN150 × PN40 | St20 | GOST 33259 |
| Weld Neck Flange, Raised Face | DN200 × PN16 | St20 | GOST 33259 |
| Weld Neck Flange, Raised Face | DN200 × PN40 | St20 | GOST 33259 |
| Weld Neck Flange, Raised Face | DN250 × PN16 | St20 | GOST 33259 |
| Weld Neck Flange, Raised Face | DN300 × PN40 | St20 | GOST 33259 |
GOST 33259 St20 Weld Neck Flanges for Industrial Pipelines
The main products supplied in this shipment are GOST 33259 St20 weld neck flanges, which are widely used in oil & gas, petrochemical, power generation, and water treatment facilities throughout Eastern Europe, Central Asia, and the CIS market.
Manufactured from St20 carbon steel, these flanges provide excellent weldability, stable mechanical properties, and reliable sealing performance. Their long tapered hub helps distribute stress evenly from the flange to the connected pipe, making them suitable for medium- and high-pressure piping systems.
For this Azerbaijan project, every GOST 33259 St20 weld neck flange was machined with raised face sealing surfaces to ensure secure gasket seating and leak-free flange connections.
GOST 33259 St20 weld neck flanges raised face manufactured by Haihao Group
Strict Control of St20 Chemical Composition
Material consistency is critical for flange reliability. During production, Haihao Group carefully verified the chemical composition of the St20 steel to ensure compliance with customer requirements.
Typical chemical composition requirements include:
- Carbon (C): 17–0.24%
- Silicon (Si): 17–0.37%
- Manganese (Mn): 35–0.65%
- Nickel (Ni): ≤0.30%
- Sulfur (S): ≤0.04%
- Phosphorus (P): ≤0.035%
- Chromium (Cr): ≤0.25%
- Copper (Cu): ≤0.30%
- Arsenic (As): ≤0.08%
By maintaining tight control over raw materials and forging processes, Haihao Group ensures that each GOST 33259 St20 weld neck flange delivers consistent mechanical performance and long-term service reliability.
Precision Manufacturing and Quality Inspection
Every flange underwent comprehensive inspections before delivery, including:
- Raw material verification
- Chemical composition analysis
- Forging quality inspection
- CNC machining
- Raised face dimensional inspection
- Flange drilling inspection
- Surface quality examination
- Final dimensional verification
- Product identification and traceability
These quality control procedures ensure every GOST 33259 St20 weld neck flange meets both the GOST standard and customer project specifications.
Trusted Flange Manufacturer for International Projects
Haihao Group has extensive experience manufacturing forged flanges for customers across Europe, the Middle East, Central Asia, and Southeast Asia.
Our manufacturing capabilities include:
- GOST, ASME, EN, DIN and JIS standards
- Carbon steel, stainless steel, alloy steel, duplex stainless steel and nickel alloy materials
- Weld neck, slip-on, blind, socket weld, threaded and special flanges
- Customized production according to customer drawings
- Complete inspection reports and export documentation
Whether your project requires standard pipeline flanges or custom-engineered components, Haihao Group delivers reliable products backed by decades of manufacturing expertise and global export experience.
Contact Haihao Group today to discuss your next pipeline project and request a competitive quotation.