HDPE (high-density polyethylene) pipe hot melt welding is a permanent connection method that melts the end of the pipe by heating and then applies pressure to fuse it. This technology can form a joint with the same strength as the pipe itself, ensuring the sealing and durability of the pipeline system.
Main advantages
1. High strength: The weld strength is close to that of the parent material
2. No leakage: integrated connection to avoid interface leakage
3. Corrosion resistance: No additional sealing material is required
4. Long life: Synchronous aging with HDPE pipe (more than 50 years)
(1) Butt hot melt welding (Butt Fusion)
Applicable pipe diameter: generally ≥90mm
Process flow:
End milling - use a milling cutter to ensure that the pipe end is flat and vertical
Heating plate heating - heating to 210±10°C (depending on the material)
Endothermic stage - maintain pressure to form a molten flange at the pipe end
Switch plate removal - quickly remove the heating plate
Welding pressurization - dock within the specified time and cool under pressure
Key parameters:
Step | Pressure (bar) | Time |
Heating | 0.15~0.3 | Adjust based on wall thickness |
Soaking | Maintain | Wall thickness (mm) × 10 (seconds) |
Cooling | Natural cooling | ≥ Wall thickness (minutes) |
(2) Electrofusion
Applicable scenarios: small diameter or complex locations
Features:
Use pipe fittings with built-in heating wire
Heat after power is turned on to fuse the materials
Operation points:
Scrape off the oxide layer (use a special scraper)
Mark the insertion depth
Power on for heating (voltage/time according to the manufacturer's instructions)
Natural cooling (forced cooling is prohibited)
(1) Pre-welding inspection
Material verification: Confirm that the pipe/fitting is the same grade PE100 or PE80
Environmental requirements:
Ambient temperature > -5℃ (a shed needs to be built for insulation in cold weather)
Relative humidity < 90%
Wind barriers need to be set up in windy weather
(2) Process control
Temperature monitoring: The surface temperature of the heating plate needs to be calibrated with an infrared thermometer
Flange shape: A qualified flange should be "double-peaked" with uniform height (reference value: wall thickness × 0.3)
Welding parameters: Strictly follow the requirements of the process card and do not adjust at will
(3) Post-weld inspection
Appearance inspection:
Flanged edges are symmetrical and free of pores
No traces of false welds or carbonization
Destructive test (sampling):
Tensile test (strength ≥ 80% of parent material)
Bending test (no delamination or cracking)
Mastering the standardized HDPE hot-melt welding technology is the core of ensuring the quality of pipeline projects.
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
HDPE (High-Density Polyethylene) pipes can be connected in various ways depending on engineering requirements, pressure ratings, and construction conditions. Below are the common HDPE pipe connection methods and their characteristics:
Application: Pressure pipe systems (e.g., water supply, gas pipelines)
Advantages: Strong sealing, high joint strength (close to the pipe material itself)
Disadvantages: Requires specialized equipment and trained operators
Type | Key Steps | Applicable Pipe Sizes |
Butt Fusion | Heats pipe ends to a molten state, then presses them together (requires trimming, temperature control at 200-220°C) | DN20-DN1200 |
Electrofusion | Uses fittings with built-in heating wires (automated temperature control, suitable for confined spaces) | DN20-DN400 |
Socket Fusion | Simultaneously heats pipe end and fitting before insertion (common for small-diameter pipes) | DN20-DN110 |
Application: Temporary projects, non-pressure pipelines, or repairs
Advantages: Quick installation, detachable
Disadvantages: Requires periodic sealing inspection
Type | Features |
Flange Connection | Bolted flange connection with gasket sealing, suitable for valve/equipment connections |
Clamp Coupling | Uses stainless steel clamps to compress rubber seals, ideal for emergency repairs or connecting different materials |
Compression Fitting | Seals via threaded compression, typically used for small pipes (DN ≤ 63) |
Method | Description |
Steel-Plastic Transition Fitting | Connects HDPE to metal pipes (internal sealing and anti-pullout structure) |
Heat-Shrink Sleeve Connection | Uses a heat-shrink sleeve to seal joints by flame heating (common for cable protection pipes) |
Pressure pipelines: Prefer heat fusion (Butt Fusion > Electrofusion)
Non-pressure pipelines: Mechanical connections are more economical (e.g., clamp couplings for drainage pipes)
Special environments:
Underground concealed works → Heat fusion
Confined spaces → Electrofusion
Temporary projects → Flange/Clamp connections
Clean pipe ends before heat fusion to avoid contamination.
Mechanical connections require periodic seal inspection (recommended replacement every 5 years).
Official website: www.phtopindustry.com | www.pefitting.net
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