HDPE pipe and fitting,PVC pipe and fitting

In modern pipeline engineering, the connection between HDPE (high-density polyethylene) pipes and steel pipes is a common technical requirement. Due to the significant differences in the properties of the two materials, how to achieve a safe and reliable connection has become the key point in the implementation of the project. This article will systematically introduce the connection methods, technical points and precautions of HDPE pipes and steel pipes.

 

Main methods for connecting HDPE pipes to steel pipes

1. Flange connection method

Working principle:

Welding PE flange joints at the end of HDPE pipes

Welding steel flanges at the end of steel pipes

Connection is achieved by bolting

Implementation steps:

Hot-melt connection of HDPE pipe ends to PE flanges

Welding matching steel flanges at the end of steel pipes

Installing sealing gaskets between the two flanges

Tightening bolts evenly and symmetrically

Advantages:

Reliable connection, strong pressure bearing capacity

Convenient for later maintenance and disassembly

Wide application range (commonly used for pressure pipes)

2. Socket and spigot connection method

Working principle:

Using steel conversion joints

One end is designed as a socket to connect HDPE pipes

The other end is designed as a spigot to connect steel pipes

Implementation steps:

Insert HDPE pipe into the socket of the joint and fix it by hot-melt

Welding steel pipes to the spigot end of the joint

Adding sealing rings to enhance sealing when necessary

Advantages:

Easy and quick installation

Applicable to small and medium-sized pipes

Relatively low cost

3. Threaded connection method

Applicable conditions:

Small diameter pipes (DN≤110mm)

Low pressure working system

Implementation points:

HDPE pipe end hot-melt threaded PE joint

Steel pipe end processing matching external thread

Use sealing tape to enhance sealing

Precautions:

Not suitable for high pressure pipes

Seal status needs to be checked regularly

 

Key technical points

1. Selection of transition joints

Material should comply with GB/T 13912 standard

Pressure level should match pipeline design requirements

Interface size should be accurately measured and confirmed

2. Hot melt connection process control

Temperature control: 200-220? is appropriate

Pressure control: 0.15-0.3MPa

Time control: adjusted according to pipe diameter

3. Anti-corrosion treatment

Steel pipe welding parts need to be treated with anti-corrosion

Anti-corrosion coating or heat shrink sleeve can be used

Contacts of dissimilar metals should be insulated

4. Stress relief measures

Set flexible joints or expansion joints

Add piers at pipeline bends

Long-distance pipeline segment connection

 

Precautions for construction

Preparation before construction:

Check the quality certification documents of pipes and fittings

Measure and record the interface size

Clean the connection parts

Installation process control:

Maintain the concentricity of the connection parts

Avoid strong assembly

Perform pressure test according to the requirements of the specification

Safety matters:

Pay attention to fire prevention during hot melt operation

Take good protection when welding steel pipes

Set up warning signs in the operation area

 

Quality acceptance standards

Appearance inspection:

No visible defects in the connection parts

Anti-corrosion layer intact

Flange bolts are tightened evenly

Pressure test:

Strength test: 1.5 times the design pressure

Tightness test: 1.1 times the design pressure

Other tests:

Ultrasonic testing when necessary

Check the welding quality of hot-melt joints

The connection between HDPE pipe and steel pipe is a key technical node in pipeline engineering. Only by selecting the appropriate connection method and strictly controlling the construction quality can the long-term safe operation of the pipeline system be ensured. In actual projects, the most economical and reliable connection scheme should be selected according to factors such as pipeline specifications, working pressure, and medium characteristics, and construction and acceptance should be carried out in strict accordance with relevant specifications and standards.

Official website: www.phtopindustry.com | www.phpipes.com
Contact us: Email:inquiry@phtopindustry.com | Whatsapp:+86 15093100892
Company address: Room 802, 8th Floor, Building 5, Jinyin Modern City, Jinshui District, Zhengzhou City, Henan Province, China