4 Connection Methods of Carbon Steel Pipes

Welding connection

Welding connection is a common connection method for carbon steel pipe. It is mainly suitable for occasions with high pressure and high working temperature in the pipeline. There are mainly the following forms of welding connection:

1. Butt welding connection

Butt welding connection is a connection method formed by aligning two pipes and filling the gap with molten metal and cooling. The carbon steel pipe connected in this way has a strong structure and strong pressure bearing capacity, but the connection process is relatively complicated.

2. Socket welding connection

Socket welding connection is a connection method formed by inserting a flat pipe at one end into another carbon steel pipe, and then filling the gap with molten metal and cooling. This connection method has a relatively simple structure and convenient operation, but there is a gap between the socket, which affects the pressure bearing capacity.

Advantages of welding connection

The welding connection is tight and reliable, with uniform force, can withstand high pressure, and is suitable for high pressure, high temperature, high flow and high viscosity fluid transportation.

Disadvantages of welding connection

The welding process is relatively complicated, requiring experienced welders, corresponding equipment and materials, and high cost.

Applicable scenarios of welding connection

Applicable to occasions with strict transportation requirements and high sealing requirements, such as petroleum, chemical, power and other industries.

Threaded connection

Threaded connection is a common and convenient connection method, suitable for low-pressure, low-temperature, small-diameter carbon steel pipes. There are mainly the following forms:

1. Internal thread connection

Internal thread connection is a way to install a carbon steel pipe with an open end in a threaded sleeve and connect it by tightening the nut. This connection method has a more uniform stress distribution on the pipe and higher reliability.

2. External thread connection

External thread connection is a way to connect a carbon steel pipe with a thread on one end in a threaded sleeve by tightening the nut. This connection method has a simple structure, but has a certain impact on the strength of the pipeline.

Advantages of threaded connection

Easy to install and disassemble, no professional personnel are required, and it can be reused.

Disadvantages of threaded connection

The threaded connection has poor sealing and is prone to leakage. Its use in high-pressure, high-temperature and low-temperature liquid transportation will be limited.

Applicable scenarios of threaded connection

Applicable to low-pressure, non-corrosive, non-explosive water, gas and other transportation occasions.

Flange connection

Flange connection is a detachable connection method, which is mainly suitable for high pressure, high temperature, large diameter, and occasions that need to be disassembled frequently. There are mainly the following forms:

1. Flat welding flange connection

The flat welding flange connection is a way to fix the flanges at both ends of the pipeline with flat washers, screws, etc., and connect them by tightening the screws. This connection method has uniform connection force distribution and good sealing, but the connection process is relatively complicated.

2. Butt welding flange connection

Butt welding flange connection is a connection method in which the pipe flange stands opposite to the two ends of the pipeline, and the connection is achieved by tightening the screws of the butt welding flange. This connection method is easy to operate, but there are certain restrictions on the diameter and wall thickness of the pipeline.

Advantages of flange connection

The flange connection is tight and reliable, easy to operate, reusable, and suitable for high pressure and high temperature transportation.

Disadvantages of flange connection

The installation process is relatively complicated, requiring the use of professional tools and operations, which increases the cost to a certain extent.

Applicable scenarios of flange connection

Applicable to high temperature and high pressure transportation, such as thermal transportation, chemical and petroleum pipelines.

Bayonet connection

The bayonet connection is a connection method based on the bayonet principle, which is mainly used in hot water, heating, air conditioning and other fields. Bayonet connection mainly has the following forms:

1. Elastic sealing bayonet connection

The elastic sealing bayonet connection is a way to cut a "V" groove at a certain angle at the end of the pipe section, clamp it on the flange structure with a clamp, and achieve connection by tightening the flange bolts. This connection method has a simple structure, quick installation, and excellent sealing.

2. Pressure sealing bayonet connection

The pressure sealing bayonet connection is a way to cut a "V" groove at a certain angle at the end of the pipe section, and use the clamp and flange structure together to form a bolt-type connection. This connection method has strong pressure bearing capacity and good corrosion resistance, but the operation is more cumbersome.

Advantages of bayonet connection

Simple and quick installation, and relatively cheap.

Disadvantages of bayonet connection

The clamp connection has poor sealing, and it is difficult to meet the requirements of high-pressure and high-temperature liquids, which is easy to cause oil leakage, liquid leakage and other problems.

Applicable scenarios of bayonet connection

It is suitable for conveying small flow liquids, such as tap water, hot water, etc.

Summary

The above are the four common connection methods for carbon steel pipes. When choosing a connection method, it is necessary to comprehensively consider factors such as different working conditions, environment, pressure and fluid characteristics, and choose the appropriate connection method to ensure the reliability and safety of the pipeline system.