Flange welding is a common and important pipe connection method. The flange and the pipe are fixed by welding to form a strong and well-sealed joint. In different working conditions and applications, it is crucial to choose the appropriate flange welding type. This article will introduce several main types of flange welding and their reference areas.
 


1. Main types of flange welding
 
1. Slip-On Flange
 
Flat welding flanges are usually used in medium and low pressure pipeline systems. They are installed by inserting the pipe into the inner ring of the flange and then welding the inner and outer rings. Due to its low welding strength, it is suitable for situations where pressure and temperature requirements are not high.
 
2. Weld Neck Flange
 
The neck of the butt welding flange has a long tapered structure and is connected to the pipe through a butt weld. It is characterized by high strength of welded joints and good pressure resistance. It is suitable for occasions with high pressure, high temperature and large temperature fluctuations, such as petrochemical and power industries.
 
3. Socket Weld Flange
 
There is a step on the inside of the socket welding flange, and the pipe is ring welded after it is inserted. This type of flange is suitable for small-diameter, high-pressure pipe systems, commonly found in high-pressure steam and hydraulic systems.
 
4. Threaded Flange
 
Threaded flanges are connected to pipes through threads and are mainly used in low-pressure pipeline systems, especially in situations where welding is not suitable, such as flammable and explosive areas. Easy to install and disassemble, but not suitable for high temperature and high pressure environments.
 
5. Lap Joint Flange
 
Split flanges are used in conjunction with butt welding rings and are mainly used in pipeline systems that require frequent disassembly. Its advantage is that it requires low pipeline alignment requirements, is easy to disassemble and assemble, and is suitable for low-pressure and high-strength applications.
 
6. Long Weld Neck Flange
 
Long neck flanges are similar to butt weld flanges, but have a longer neck. They are mainly used in applications that require enhanced strength of welded joints, such as high-pressure vessels and boiler systems.
 
2. Reference fields of flange welding
 
1. Petrochemical industry
 
In the petrochemical industry, piping systems are often subjected to high temperatures, high pressures and corrosive environments. Butt welding flanges are widely used in high-pressure transportation pipelines in oil refining and chemical plants due to their high strength and good sealing properties.
 
2. Electric power industry
 
Systems such as power plants and nuclear power plants in the power industry require pipeline systems to have extremely high reliability and pressure resistance. Butt welding flanges and long neck flanges are often used in such high pressure and high temperature applications to ensure stable operation of the system.
 
3. Shipbuilding and Marine Engineering
 
In shipbuilding and offshore engineering, flange welding is used for various pipeline connections on ship pipelines and offshore platforms. Due to the particularity of the marine environment, material selection must have good corrosion resistance. Socket welding flanges and flat welding flanges are common choices.
 
4. Natural gas transportation
 
Natural gas transmission pipelines require high sealing and safety. Butt welding flanges and threaded flanges are widely used in natural gas pipeline systems due to their excellent sealing performance and ease of installation.
 
5. Food and pharmaceutical industry
 
The food and pharmaceutical industries have extremely high requirements for hygienic conditions, and flange welding is used to connect pipeline systems to ensure that there are no dead corners and are easy to clean. Sanitary flat welding flanges and butt welding flanges are widely used in these fields.
 
6. Water supply and drainage
 
In municipal water supply and drainage systems, flange welding is used to connect large-diameter pipes, which requires the connection to be firm and able to withstand a certain pressure. Flat weld flanges and split flanges are commonly used for this type of pipe connection.
 
in conclusion
 
As an important method of pipe connection, flange welding has various types and a wide range of applications. Choosing the appropriate flange type according to specific working conditions can ensure the safe and efficient operation of the pipeline system. In practical applications, selecting the most appropriate flange welding method by comprehensively considering pressure, temperature, medium characteristics and installation and maintenance requirements is a key link in pipeline design and construction.