Flanges
Flange is a disk-shaped component used to connect pipes, valves or equipment in mechanical and piping systems, with bolt holes evenly distributed around the edges to realize a removable sealing connection through bolt fastening. It is usually used in conjunction with sealing gaskets to ensure the safe transmission of media in high-pressure, high-temperature or corrosive environments, and its core functions include standardized interface docking, segmented maintenance convenience, and system sealing guarantee. According to the needs of application scenarios, flanges can be designed as flat welding, butt welding, threaded and other structures, with materials covering carbon steel, stainless steel and alloy steel, and in accordance with the international standard system such as DIN, ANSI, GB and other international standards, in order to meet the diversified needs of industrial pipelines, energy transmission and equipment interfaces.
American Flange
EN /BS flang
Grooved Flange
Flanges Specifications
Standard: ANSI/ASME B16.5, DIN EN 1092-1
Size: NPS 1/2″~24”
Pressure Rating: Class 150~2500
Material: carbon steel, stainless steel, alloy steel
Type: SO, WN, Threaded Flange, Blind Flange
Connection: Butt Weld, Socket Weld
Surface: epoxy resin, galvanized
Flanges Process
Material Selection and Pretreatment
According to the application scenario, carbon steel, stainless steel, duplex steel or aluminum alloy are selected to meet the requirements of strength and corrosion resistance. After cutting the round steel or plate into billet, heat it to 950-1050℃ or above 800℃ to ensure the material plasticity.
Molding process
Casting method:Sand casting: suitable for low-cost, complex shape flanges, but prone to porosity, inclusions defects.
Centrifugal casting: Molten steel is injected into the rotating mold through centrifugal machine, and a dense structure is formed after cooling to reduce internal defects.
Forging method
Free Forging: Gradual molding through upsetting, elongation, punching, bending and other processes, suitable for small batch or large flange production.
Die forging: the billet is put into the pre-processing mold and pressurized to form, with high efficiency and uniform grain organization, suitable for large batch of standard flanges.
Heat treatment
Normalizing/Annealing: Eliminate forging stress and refine grain structure.
Mechanical Processing
Turning flange end face, outer circle and sealing surface. Drilling, chamfering and polishing to ensure dimensional accuracy (tolerance ±0.1mm).
Quality inspection and surface treatment
X-ray or ultrasonic flaw detection (UT) to check internal cracks, air holes; magnetic particle testing (MT) to detect surface defects. Measurement of bolt hole center distance, flange thickness and other parameters. Spraying epoxy resin, galvanizing or overlaying stainless steel layer to enhance environmental corrosion resistance.
Grooved Couplings Advantage
Structural Design Advantages
High sealing: Through bolt fastening and gasket coordination, it forms a leak-free connection, suitable for high pressure, high temperature and corrosive media scenarios.
Anti-vibration and shock: flange design allows axial and radial displacement compensation, which can absorb pipeline vibration and thermal expansion and contraction stress, reducing the risk of system fatigue failure.
Ease of Installation and Maintenance
Removable connection: Flanges are bolted for easy sectional maintenance, equipment replacement or system expansion, reducing downtime.
Standardized interfaces: follow ANSI, DIN and other standards to ensure compatibility of pipelines, valves and equipment from different manufacturers, reducing the difficulty of matching.
Diversified types to match complex needs
Flat welding flange (SO): low cost, suitable for low pressure (≤ Class 300) and non-hazardous media.
Butt-welding flange (WN): neck thickening design, enhanced rigidity, suitable for high pressure (Class 600+) and frequent thermal cycle scenarios.
Threaded flanges: weld-free installation, suitable for restricted spaces or pipelines requiring frequent disassembly (e.g. instrumentation pipelines).
Socket weld flange: simplifies the fillet welding process for small-diameter pipes (DN≤50) and improves construction efficiency.
Material and Process Expansion
Corrosion resistance: optional stainless steel, duplex steel or coating treatment, adapting to acid, alkali, seawater and other harsh environments.
Dynamic compensation ability: flange type expansion joint can be free to expand and contract ±15mm, to compensate for pipeline displacement and avoid rupture caused by stress concentration.