Product details description

Butt-welding flange is a kind of pipe fittings, which refers to the flanges with necks and with round pipe transitions and butt-welded connections with pipes.

The scope of application of butt-welding flange

Butt-welding flange is not easy to deformation, good sealing, wide range of applications, there are corresponding rigidity and elasticity requirements and reasonable butt-welding thinning transition, welding mouth from the joint surface of a large distance, the joint surface from the welding temperature deformation, which takes a more complex Loudspeaker-shaped body structure, for pressure or temperature fluctuations in large quantities of the pipeline or high temperature, high pressure and low temperature pipeline, generally used for the connection of the pipeline and the valve with a PN greater than 2.5MPa; Also used for conveying expensive, flammable and explosive media on the pipeline.

Technical requirements:

I. The level of butt-welding flange and its technical requirements should be in line with the corresponding requirements of JB4726-4728.

1, nominal pressure PN 0.25MP-1.0MPa carbon steel, austenitic stainless steel forgings are allowed to use Ⅰ level forgings.

2, in addition to the following provisions, the nominal pressure PN of 1.6MPa-6.3MPa forgings should be in line with the requirements of Grade II or Grade II or above forging level.

3、It shall meet the requirements of Ⅲ and forgings if it meets one of the following conditions:

(1) Nominal pressure PN ≥ 10.0MPa flange forgings;

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

(3) Nominal pressure PN>1.6MPa and working temperature ≤ -20 degrees Celsius ferritic steel forgings.

Second, butt-welding flanges are generally made of forgings or forging and rolling process. When made of steel plate or section steel, it must meet the following requirements:

1, Butt-welding flange should be ultrasonic flaw detection, no delamination defects;

2, should be cut into strips along the direction of steel rolling, by bending butt-welding into a circle, and make the surface of the steel to form the column surface of the ring. The steel plate shall not be directly machined into necked butt weld flanges;

3. The butt weld of the ring shall be a full penetration weld;

4. The butt weld of the ring shall be heat-treated after welding and ray or ultrasonic flaw detection, and the ray flaw detection meets the requirements of Grade II of JB4730, and the ultrasonic flaw detection meets the requirements of Grade I of JB4730.

Third, the slope of the outside of the neck of the butt-welding flange should be no more than 7o. butt-welding flange in the production and welding of strict control of the technical parameters, * to be able to give full play to the role and value in the production and use.

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