Knowledge of 12 flanges from flange supplier(2)

- Jun 21, 2019-

3. Butt welding flange with neck


 Flat neck welding flange with full neck flat welded steel pipe flange. English Name: Slip-on SO

The flat welding flange with neck is the same as the plate type flanging flange, and it also extends the steel pipe and fittings into the flange and connects the flange with the equipment or pipe through the fillet weld.

The sealing surface of flat welding flange with neck is in the form of:

RF (surface), concave (FM), convex (M), tenon (T), groove face (G), full plane (FF).

The diameter range of flat welding flange with neck is DN10~DN600

Scope of application: PN series PN2.5~PN40; Class series Class150~Class1500

Flange materials: carbon steel, molybdenum molybdenum steel, 304, 316, 304L, 316L, 321, 347, CF8C.

Manufacturing process: forging.

Advantages: flat neck welding flange is also flat welding flange, because there is a short neck, thereby improving the strength of the flange to improve the bearing capacity of the flange. So it can be used for pipes with higher pressure.

Disadvantages: cost is higher than plate type flat welding flange, because of its shape characteristics, it is easier to bump in transportation.

4.Integral flange


The integral flange is a connection mode of flange. It is also a kind of butt welded steel pipe flange with neck. Materials include carbon steel, stainless steel, alloy steel, etc. IF is used to represent the integral flange in various domestic standards. It is mostly used in pipes with high pressure. The production process is generally casting.

In the type of flange, an IF is used to represent the type of integral flange. Generally, it is a protruding surface (RF). If it is used in flammable, explosive, high and extremely harmful working conditions, it is possible to choose the form of convex concave surface (MFM) and tenon groove surface (TG) seals besides the RF surface.

5.Socket welding flange



The socket welding flange is a flange connected with one end of the steel pipe and the other end by bolts.

The form of sealing surface: RF, MFM, TG and RJ.

Applications: Boiler and pressure vessel, petroleum, chemical industry, shipbuilding, pharmaceutical, metallurgy, machinery, stamping elbow food and other industries socket welding flange: commonly used in PN less than 10.0MPa, DN or less than 40 of the pipeline;

6.Threaded flange


The threaded flange is made from the inner hole of the flange into pipe thread and connected with the pipe with thread, which is a non welded flange. Compared with the flat welding flange or butt welding flange, the threaded flange has the characteristics of convenient installation and maintenance, and can be used on some pipelines which are not allowed to be welded on the spot. Alloy steel flanges are of sufficient strength, but they are not easy to weld or have poor weldability. Threaded flanges can also be selected. However, if the temperature changes rapidly or the temperature is higher than 260 C below -45 C, it is recommended not to use threaded flange to avoid leakage.

7. Butt Welding Ring Loose Sleeve Flange


The flanged flange of the butt welded ring and the flange of the welded ring are movable flanges, which are generally matched to the fittings for water supply and drainage. When the manufacturer is out of factory, each flange has two flanges directly connected to the pipeline and equipment in the project by bolts.

Function: the purpose of using loose ring flange is to save material. Its structure is divided into two parts. The pipe part is connected to the pipe and the head is welded. The flanges are made of low grade materials, while pipes are made of materials similar to pipes.

Welded ring loose flange:

1, cost saving. When the pipe material is special and expensive, the cost of welding flange with the same material is high.

2, not easy to weld or not easy to process or require great strength. Such as plastic pipes, fiberglass pipes and so on.

3, convenient for construction. For example, flange bolt holes are not easy to locate when connecting, or prevent changing bolt holes of equipment flange in future.


1, under low pressure.

2. The strength of the welding ring is low (especially under the thickness of 3mm).

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