HDPE pipe and fitting,PVC pipe and fitting

High-density polyethylene (HDPE) pipes are widely used in water supply, drainage, gas transmission, and industrial pipelines due to their excellent corrosion resistance, flexibility, and long service life. Heat fusion is the primary connection method for HDPE pipes, and its quality directly affects the safety and lifespan of the entire pipeline system. This article details the precautions for HDPE pipe heat fusion to help operators master the correct procedures.

Pre-Connection Preparations

1. Material Inspection

Pipe Quality Verification: Ensure HDPE pipes and fittings comply with GB/T 13663 or ISO 4427 standards.

Dimensional Check: Confirm matching specifications and wall thicknesses between pipes and fittings.

Surface Cleaning: Remove dirt, grease, and oxidation layers from pipe ends.

2. Environmental Conditions

Temperature Requirements: Ambient temperature should be between -5°C to 45°C.

Wind Protection: Use windbreaks for outdoor work to prevent wind interference.

Rain & Moisture Prevention: Avoid construction in rain/snow; keep connection areas dry.

3. Equipment Check

Fusion Machine Calibration: Verify heating plate temperature accuracy (210±10°C).

Clamp Inspection: Ensure clamps are clean and provide sufficient gripping force.

Stable Power Supply: Prevent voltage fluctuations affecting heating performance.

 

Heat Fusion Operation Guidelines

1. Butt Fusion (Fusion Joining) Precautions

Pipe End Preparation:

Use a special milling tool to ensure flat end surfaces.

Perform fusion immediately after milling to avoid contamination.

Heating Process:

Maintain heating plate temperature at 210±10°C.

Heating time: ~10 seconds per 1mm wall thickness.

Apply moderate pressure to avoid excessive "bead" formation.

Joining Process:

Transition time (heating plate removal to joining) must not exceed limits.

Apply uniform joining pressure to prevent misalignment.

Allow sufficient cooling time—no forced cooling.

2. Electrofusion Precautions

Pipe End Prep:

Remove oxidation layer (depth: 0.1–0.2mm) from the joint area.

Mark insertion depth to ensure proper pipe seating.

Power Control:

Use a voltage stabilizer for consistent power supply.

Strictly follow voltage and time parameters specified by the fitting manufacturer.

Cooling Phase:

Allow natural cooling post-fusion.

Do not move or pressurize pipes during cooling.

Common Issues & Preventive Measures

Issue	Possible Cause	Prevention
Uneven fusion surface	Uneven heating plate/poor pipe end prep	Regularly inspect heating plate/ensure proper milling
Weak joint strength	Insufficient heating/pressure/rapid cooling	Strictly control parameters/allow full cooling
Pipe misalignment	Clamp misalignment/improper operation	Adjust clamps carefully/follow procedures
Contaminated joint	Poor cleaning/dirty environment	Thorough cleaning/improve work conditions

Quality Inspection Standards

1. Visual Inspection

Fusion bead should be uniform and continuous.

No bubbles, cracks, or defects.

Bead height must meet standards.

2. Pressure Testing

Perform hydrostatic strength test (GB/T 19471.2).

Test pressure: 1.5× working pressure.

3. Destructive Testing

Conduct tensile tests on samples periodically.

Fracture should occur in the pipe body, not the joint.

 

HDPE pipe heat fusion requires technical expertise and experience. Strict adherence to procedures and precautions ensures joint integrity and system safety. Regular operator training and a robust quality control system are recommended for optimal results.

By following these guidelines, installation quality and pipeline longevity can be significantly improved, reducing maintenance costs and ensuring long-term reliability.