GB Butt Welding Flanges

The butt welding flange is now no longer common to deform, seals well, is widely used, has the corresponding rigid and elastic necessities and realistic butt welding thinning transition, the welding joint is a lengthy way from the joint surface, and the joint flooring is blanketed from welding temperature deformation, it adopts a increased intricate cough flare structure, which is gorgeous for pipelines with large fluctuations in stress or temperature or pipelines with immoderate temperature, immoderate pressure and low temperature, and is typically used for the connection of pipelines and valves with PN accelerated than 2.5MPa, and is moreover used for transporting expensive, flammable and explosive medium pipelines.

Forging, casting, and mid-plate turning

Flat welded flanges

Connection form: Single-sided welding, double-sided nut connection.

Product factors Beautiful appearance, easy surface, acid and alkali resistance, anti-corrosion, sturdy texture performance.

Production process: Oxygen furnace cutting, integral forging or accomplished product forging and decreasing forming.

Processing method: high-precision CNC lathe turning, CNC radial drilling and drilling.

Product parameters

(2) Bolt hole center circle diameter: 50mm----2130mm

(3) Bolt hole diameter: 11mm-30mm

(6) Flange thickness: 12mm-58mm

(7) TUBE OUTER DIAMETER: A(17.2-2032MM) B(14-2020MM)

(8) Flange inside diameter: A(18-2036MM) B(15-2024MM)

(9) Flange theoretical weight: 0.36kg--234.6kg (DN1800)

1. The grade of the butt welding flange and its technical requirements should meet the corresponding requirements of JB4726-4728. 　1. Carbon steel and austenitic stainless steel forgings with nominal pressure PN of 0.25MP-1.0MPa are allowed to use Class I forgings. 　2. In addition to the following provisions, forgings with nominal pressure PN of 1.6MPa-6.3MPa shall meet the requirements of grade II or above forging grades. 　3. Those who meet one of the following conditions shall meet the requirements of III. and forgings: (1) Forgings for flanges with nominal pressure PN≥10.0MPa; (2) Chromium-molybdenum steel forgings with nominal pressure PN>4.0MPa; (3) Ferritic steel forgings with nominal pressure PN>1.6MPa and working temperature ≤-20 degrees Celsius.

2. Butt welding flanges are generally made of forgings or forging and rolling processes. When manufactured with steel plates or sections, the following requirements must be met: 1. The butt welding flange should be tested by ultrasonic flaw without delamination defects; 2. It should be cut into strips along the rolling direction of the steel, and formed into a ring by bending and butt welding, and the surface of the steel should form a cylindrical surface of the ring. The steel plate shall not be directly machined into a butt welding flange with a neck; 3. The butt weld of the ring should be fully penetrated weld; 4. The butt weld of the ring should be heat treated after welding, and 100% ray or ultrasonic flaw detection should be done, and the ray flaw detection meets the requirements of JB4730 Class II, and the ultrasonic flaw detection meets the Class I requirements of JB4730.

3. The slope of the outer side of the neck of the butt welding flange should not be greater than 70°. The butt welding flange strictly controls the technical parameters during production and welding to ensure that it can play a full role and value in production and use.