Hot-melt connection "zero leakage": How does PE pipe solve the problem of pipeline interface leakage?

2025-06-06

Molecular-level fusion of hot-melt connection

Molecular diffusion and winding When the PE pipe is hot-melted, the heating plate melts the surface of the pipe end (temperature 200-230℃), and the two ends of the PE pipe fitting are fitted under pressure. Polyethylene molecular chains diffuse and entangle with each other in the molten state, and form a homogeneous seamless connection after cooling, and its strength is even higher than that of the pipe body. Traditional flanges or mechanical connections rely on external seals, while hot melting achieves material body fusion, eliminates interface leakage paths, and prevents leakage of materials in the pipe.

Triple sealing structure formation--

Curling shape: When heated, the pipe end is squeezed to form a uniform flange (height ≥ 10% of the pipe wall thickness), which becomes a ring-shaped reinforcement rib after cooling;

Densification of the molten zone: Molten PE fills the microscopic defects on the surface of the pipe, eliminating pores and cracks;

Pressure self-tightening effect: The higher the internal pressure of the pipeline, the greater the compression force of the weld surface, and the stronger the sealing.

Key steps to achieve "zero leakage"

parameter	Standard range	effect	Risk of loss of control
Heating temperature	200–230℃	Ensure sufficient melting	Insufficient temperature → false welding; too high temperature → carbonization
Heating pressure	0.15–0.3MPa	Forming uniform curling edges	Uneven pressure → flange height deviation
Endothermic time	Pipe wall thickness (mm) × 10–12 seconds	Heat penetrates deep into the pipe wall	Insufficient time → insufficient penetration
Switching time	≤5 seconds	Prevent oxidation of the molten surface	Overtime → surface hardening failure
Cooling time	Pipe wall thickness (mm) × 1–1.5 minutes	Molecular chain crystallization solidification	Early disturbance → internal stress cracking