Butt fusion is a thermofusion process, involves the simultaneous heating of the ends of two pipe/fitting components
which are to be joined, until a molten state is attained on each contact surface.
The two surfaces are then brought together under controlled pressure for a specific cooling time and a homogeneous fusion joint is formed. The resultant joint is fully resistant to end loads and has comparable performance under pressure to the pipe itself.
Electrofusion welding is a form of resistive implant welding used to join pipes. A fitting with implanted metal coils is
placed around two ends of pipes to be joined, and current is passed through the coils.
Resistive heating of the coils melts small amounts of the pipe and fitting, and upon solidification, a joint is formed. It is most commonly used to join polyethylene (PE) and polypropylene (PP) pipes. Electrofusion welding is the most common welding technique for joining PE pipes