Pipe welding flange selection guide

In pipeline engineering, pipe flanges are important components for connecting pipelines, and their selection is crucial. This article will give you a detailed introduction to the selection points of pipe welding flanges, helping you to easily select the pipe flange that best suits your needs.

Pipe flange materials:

1. Carbon steel flanges
Carbon steel flanges are one of the most common flanges in pipeline engineering. They are moderately priced and have high strength and rigidity. Carbon steel flanges are suitable for pipeline systems of general pressure levels and temperatures, but are easily damaged in corrosive media.

2. Stainless steel flanges
Stainless steel flanges have excellent corrosion resistance and can be used for a long time in harsh environments. The price of stainless steel flanges is relatively high, but their long service life and low maintenance costs make them more cost-effective.

3. Alloy steel flanges
Alloy steel flanges have high strength and rigidity as well as good corrosion resistance. Alloy steel flanges are suitable for pipeline systems with high temperature, high pressure and corrosive media. However, their price is high and needs to be weighed according to specific project requirements.

Types of welding flanges:

1. Flat-weld flange
A flat-weld flange is a flange that is welded by inserting a pipe into the inner hole of the flange. It has a simple structure and is easy to process and install. Flat-weld flanges are suitable for pipeline systems with lower pressure levels.

2. Butt-weld flange
A butt-weld flange is a flange that is connected through the butt weld between the pipe and the flange. It has high connection strength and good sealing. Butt-weld flanges are suitable for pipeline systems with higher pressure levels.

3. Socket-weld flange
A socket-weld flange is a flange that is welded by inserting a pipe into the socket of the flange. Socket-weld flanges are suitable for connecting pipeline systems with larger pipe diameters and thinner wall thicknesses.

When selecting pipeline welding flanges, in addition to considering materials and types, the following points should also be noted:

1. The pressure level of the flange should match the working pressure of the pipeline system to ensure the safe operation of the system.
2. The sealing surface type of the flange should be selected according to the properties of the medium, such as flat seal, concave and convex surface seal, tongue and groove surface seal, etc.
3. The connection size of the flange should comply with relevant national standards or industry specifications to ensure smooth connection with the pipeline system.

Pipe flange selection:
When selecting a pipe flange, technical parameters such as medium, temperature and pressure need to be considered. Generally speaking, low-pressure systems (PN<2.5MPa) are suitable for flat welding or plate flanges with ordinary raised face (RF) seals; medium-pressure systems (2.5-64MPa) are recommended to use butt welding flanges with raised face (RF) or concave and convex face (FM/M) seals; high-pressure systems (above 10.0MPA) usually also use butt welding flanges, and tongue and groove face (TG) and ring joint (RJ) sealing faces can be considered. In stainless steel low-pressure systems, loose flanges or slip-on ring flanges are sometimes selected to save costs and facilitate maintenance. In addition, integral flanges are flanges that are made into one piece with equipment, pipes, etc. This form is more common on equipment and valves, but less used in pipes and fittings.

Conclusion:

Choosing a pipeline welding flange that suits your needs requires consideration of many factors. The selection of pipeline welding flanges needs to consider factors such as material, pressure level, and sealing surface type. Common flanges include carbon steel flanges, stainless steel flanges, and alloy steel flanges, which need to be determined based on the pipeline material, working pressure, and medium properties. I hope this article can provide you with some useful references to help you easily select the most suitable flange.

Read more: Standard sizes of pipe flanges