Butt welding flange

The butt welding flange is a kind of pipe fitting, which is the flange that has the neck and has a circular tube and is welded to the pipe. Butt welding flange is not easy to deformation, good sealing, wide application, have corresponding rigid and elastic demand and reasonable butt thinning transition, joint good distance away from the joint face the faying surface from welding deformation temperature.

Standard and classification of welding flange:

Common production standards: standard HG/T20592-2009, HG/t20615-2009, national standard GB/t9115.1-2000, GB/t9115.2-2000, GB/t9115.3-2000, GB/t9115.4-2000, mechanical department standard JB/t86.2-94, Marine standard CB/t47-1999

Butt welding flange, including a variety of types and model's butt welding steel flange and pipe flange is used for welding, mainly use in welding technology, the use of good characteristics and performance of the structure is reasonable, the strength and stiffness is bigger. It is necessary to ensure the specific use value and performance of welding flanges according to the specific situation, and withstand high temperature and high pressure.

Technical requirements:

1. The level of welding flange and its technical requirements shall comply with the corresponding requirements of jb4726-4728.

1, the nominal pressure PN 0.25 MP 1.0 MPa carbon steel and austenitic stainless steel forgings allowed the use of level Ⅰ forgings.

2, in addition to the following provisions, nominal pressure of PN 1.6 MPa to 6.3 MPa forgings shall conform to Ⅱ level or above level Ⅱ forgings levels.

3, conform to one of the following should accord with the requirement of Ⅲ and forgings:

(1) nominal pressure PN is equal to 10.0MPa flanged forging;

(2) nominal pressure PN>4.0MPa chrome molybdenum steel forgings;

(3) nominal pressure PN>1.6MPa and the working temperature is less than -20c ferrite steel forgings.

The welding flange is usually made of forging or forging rolling process. When used in the manufacture of steel plates or sections, the following requirements must be met:

1. The welding flange should be ultrasonic flaw detection, no stratification defect;

2. Cut into strips in the direction of steel rolling, welded into rings by bending, and make the surface of the steel ring on the cylinder. The steel plate direct machine is not allowed to be machined into neck butt welding flange;

3. Full penetration weld shall be used for the butt weld of the ring;

4. The butt weld of the ring shall be treated with heat treatment after welding, and shall be 100% ray or ultrasonic inspection, and the X-ray inspection shall meet JB4730's level II requirements, and the ultrasonic inspection shall meet the I level requirements of JB4730.

The lateral Angle of the neck of welding flange should not be greater than 7o. The welding flanges strictly control technical parameters during production and welding, and guarantee the full play and value in production and use.

Purpose of welding flange:

Butt welding flange of the wide range of USES, use according to the characteristics of different, more than in the mild conditions of medium, such as suit low circulating water, the purification of compressed air, and it has the advantage of the price is cheaper. Suitable for the steel tube pipe with no more than 2.5mpa, the sealing surface of welding flange can be made of smooth, concave and grooved type 3 kinds. The application of smooth butt welding flange is large, and the welding flange of the other two methods is also more common in use.

Application range of welding flange:

Butt welding flange is not easy to deformation, good sealing, wide application, suitable for pressure or temperature fluctuations of pipeline or high temperature, high pressure and low temperature pipes, advantage is that the price is cheaper, nominal pressure no more than 2.5 MPa; It is also used to transport expensive, flammable and explosive media, and the nominal pressure is around PN16MPa.