HDPE pipe and fitting,PVC pipe and fitting

High-Density Polyethylene (HDPE) pipes are widely used in water supply, drainage, gas, and chemical industries due to their advantages such as corrosion resistance, impact resistance, and long service life. The welding methods for HDPE pipes mainly include Butt Fusion and Electrofusion, ensuring a leak-free and high-strength pipeline system.

 

Butt Fusion Welding Steps

1. Preparation

Inspect equipment: Ensure the hot melt welding machine (heating plate, clamps, hydraulic system) is functioning properly.

Clean pipe ends: Use alcohol or a non-woven cloth to remove dirt, grease, and oxidation from the pipe ends.

Align pipes: Secure the pipes with clamps to ensure flat and aligned ends, with misalignment ≤10% of wall thickness.

2. Heating Phase

Set temperature: The heating plate temperature is typically 200–220°C (adjust based on pipe specifications).

Apply pressure:

Insert the heating plate between the pipe ends and apply initial pressure (0.1–0.2 MPa).

Observe the bead height; once it reaches the standard value (e.g., ~2 mm for DN110 pipes), reduce pressure and maintain heating time (refer to the table below).

Pipe Diameter (mm)	Heating Time (sec)	Changeover Time (sec)	Cooling Time (min)
DN63	30–40	≤5	6–8
DN315	120–150	≤8	20–25

3. Changeover and Fusion

Quickly remove the heating plate: Complete within 5 seconds to avoid heat loss.

Apply fusion pressure: Immediately apply butt pressure (0.15–0.3 MPa) to ensure thorough material bonding and uniform bead formation.

4. Cooling and Inspection

Natural cooling: Maintain pressure until the cooling time ends (see table). Do not move the pipes during this period.

Check the weld: The bead should be symmetrical, without cracks or depressions.

Electrofusion Welding Steps

1. Preparation

Select electrofusion fittings: Ensure the fittings match the pipe specifications (e.g., DN110 electrofusion coupler).

Mark insertion depth: Mark the insertion line on the pipe end to avoid improper fitting placement.

2. Cleaning and Assembly

Remove oxidation layer: Use a scraper to remove 0.1–0.2 mm of the pipe surface to expose fresh material.

Install fittings: Insert the pipe into the electrofusion coupler up to the marked line and secure with clamps to prevent misalignment.

3. Power-On Welding

Input parameters: Scan the barcode or manually enter welding parameters (voltage, time) from the fitting label.

Start welding: The machine will heat automatically. Observe the indicator holes for molten material overflow.

4. Cooling and Testing

Natural cooling: Cooling time should be ≥ specified duration (typically 10–30 minutes).

Leak test: Verify sealing integrity through air or hydrostatic pressure tests.

Welding Precautions

Environmental requirements: Avoid working in strong wind, rain, or low temperatures (<–5°C). Use windbreaks if necessary.

Quality checks:

Butt fusion bead height tolerance ≤10%.

Electrofusion indicator holes should show uniform material rise.

Safety measures: Wear heat-resistant gloves and goggles to prevent burns or arc flash injuries.

 

Common Issues & Solutions

Uneven bead: Caused by uneven heating plate temperature or insufficient pressure. Recalibrate equipment.

Poor electrofusion joint: Due to incomplete oxidation removal. Re-scrape and reweld.

 

Mastering Butt Fusion and Electrofusion techniques is essential for ensuring long-term stability of HDPE pipeline systems. Operators should undergo professional training and strictly follow welding parameters.

(This guide applies to HDPE pipes from DN20–DN1200 mm. For PVC pipes, adjust temperature to 170–190°C.)

For detailed parameter tables or operation videos, contact us for technical support!

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