The connection methods for steel pipes are diverse, primarily depending on factors such as the material, purpose, diameter, and required working pressure of the steel pipe. Here are some common connection methods for steel pipes:
- Welding:
- Also known as fusion welding, it is a manufacturing process and technology that joins metals or other thermoplastic materials through heating, high temperatures, or high pressure.
- Modern welding energy sources include gas flames, electric arcs, lasers, electron beams, friction, and ultrasonics.
- Welding connections are the most important and widely used connection method in pipeline engineering. They are sturdy and durable, not prone to leakage, and have high joint strength and tightness. They require little maintenance after use.
- Welding is suitable for non-galvanized steel pipes and is mostly used for concealed piping and larger diameter pipes, with more applications in high-rise buildings.
- Threaded Connection:
- A detachable fixed connection with advantages such as simple structure, reliable connection, and easy installation and disassembly. It is widely used in mechanical engineering and connection structures.
- It uses threaded pipe fittings for connection and is suitable for galvanized steel pipes with a diameter of 100mm or less, mostly used for exposed piping.
- Steel-plastic composite pipes also generally use threaded connections.
- Flange Connection:
- A detachable joint that places a gasket between a pair of flanges fixed on the ends of two pipes and tightly combines them with bolts.
- Flange connections are generally used at the main trunk line connections with valves, check valves, water meters, water pumps, etc., as well as on pipe sections that require frequent disassembly and maintenance.
- Larger diameter pipes often use flange connections.
- Groove Connection (Clamp Connection):
- Also known as clamp connection, it is a new type of steel pipe connection method.
- Groove connection fittings mainly consist of a sealing rubber ring, clamp, and locking bolts. The inner rubber sealing ring is placed on the outside of the pipe to be connected and fits with the pre-rolled groove. Then, a clamp is placed outside the rubber ring and tightened with bolts.
- Groove connections have advantages such as simple operation, no impact on the original characteristics of the pipe, safe construction, good system stability, and easy maintenance.
- It can be used for galvanized steel pipes with a diameter of 100mm or more in systems such as fire protection water, air conditioning cold and hot water, water supply, and rainwater.
- Bell and Spigot Connection:
- The spigot end of a pipe or fitting is inserted into the bell end of the mating piece, and a sealing material is used in the annular gap for sealing.
- Bell and spigot connections can be used for galvanized steel pipes, but galvanized steel pipes cannot be welded, so they are usually connected by threading, threaded flanges, or groove clamps. For stainless steel pipes, socket welding can be used.
- Press-fit Connection:
- A new type of connection mainly used for aluminum-plastic composite pipes, stainless steel pipes, etc.
- During installation, the special sealing ring of the socket fitting is connected to the pipe, and the pipe opening is pressed with a special tool to achieve sealing and tightening.
- Press-fit connections have advantages such as easy installation, reliable connection, economic rationality, and the ability to protect water quality and hygiene, with strong corrosion resistance and long service life.
- Hot-melt Connection:
- Mainly used for the connection of plastic pipes such as PPR pipes.
- A hot-melt machine is used to heat the connection area, making it melt, and then the joint is fused under specified pressure and time to form a uniform welding ring.
In summary, the connection methods for steel pipes are diverse, and the choice depends primarily on the specific application scenario and requirements. In actual engineering, the most suitable connection method should be selected based on comprehensive consideration of factors such as the material, specification, working environment, and construction conditions of the steel pipe.
