Heat fusion process is a widely used and recognized technology for welding high-density polyethylene (HDPE) pipes. It has become increasingly popular when it comes to forming HDPE spiral pipe due to its high success rate and minimal risk of defects. Compared to other welding processes, heat fusion requires no additional hardware, making it easier and more cost-effective to use. The process involves heating the surface of the pipe to a specific temperature and then pressing the two pieces together, forming an oxygen-tight seal.