A flat welding flange is a cost-effective connection component designed to slide over the pipe end and be fillet welded to the pipe shell, differing from weld-neck types by typically lacking a tapered hub. Manufactured primarily from high-quality carbon steel plates (such as Q235B, S235JR, or SS400) or forged rings, these flanges are engineered for simpler alignment and reduced material usage. The internal bore is slightly larger than the pipe's outer diameter, allowing for easy adjustment of the pipe length prior to welding, which significantly reduces fabrication time. They are specifically suitable for low-to-medium pressure systems, utilizing either Flat Face (FF) or Raised Face (RF) sealing surfaces to compress gaskets effectively.
Application Areas
In general infrastructure, the flat welding flange is the preferred choice for pipeline systems where high stress, severe vibration, or extreme fluid surges are not present. They are extensively utilized in municipal water distribution networks, irrigation systems, and firefighting water lines due to their economic advantage and ease of assembly. Additionally, these flanges are standard components in the shipbuilding industry and general circulating cooling water systems in power plants, where they connect low-pressure valves and pumps without requiring the precise bevel preparation needed for butt-weld alternatives.
Certificates and Standards
We certify that our flat welding flange production meets established international specifications, including GB/T 9119, DIN 2573/2576, JIS B2220, and EN 1092-1. Our quality management system operates under ISO9001 and ISO14001 certification, ensuring consistent material traceability from the raw steel plate to the finished product. Furthermore, our compliance with the EU Pressure Equipment Directive (PED) validates that these components meet the mechanical properties and safety benchmarks required for regulated industrial markets.
Our Factory
At our production base in the Yanshan County Development Zone, every flat welding flange is processed using high-speed multi-spindle drilling and precision CNC turning to ensure accurate bolt hole positioning and face flatness. We possess the capability to manufacture these flanges across a wide size range (DN15 to DN2000), supporting custom drilling patterns based on GOST, JIS, or DIN standards to match specific regional requirements. Our streamlined production workflow allows for the rapid turnover of large wholesale volumes, with strict dimensional inspections conducted to verify the inner bore diameter and sealing face quality before the protective anti-rust coating is applied.
Frequently Asked Questions (FAQ)
Q: What is the main difference between a Flat Welding (Plate) flange and a Weld Neck flange?
A: A Flat Welding flange slides over the pipe and is fillet welded, making it easier to align and cheaper to produce. A Weld Neck flange has a tapered hub that is butt-welded to the pipe, providing the structural reinforcement needed for high-pressure or high-temperature applications.
Q: Can you produce these flanges from steel plate?
A: Yes. For lower pressure ratings (like PN6 or PN10), we often manufacture these from certified carbon steel plates, which reduces cost. For higher pressure ratings, we use forged rings to ensure greater material density.
Q: What is the standard sealing face for these flanges?
A: The most common sealing faces are Flat Face (FF) and Raised Face (RF). We can machine the face roughness (serrated or smooth) according to the type of gasket you intend to use.
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