PEX pipe, or cross-linked polyethylene pipe, is a type of pipe that transforms the linear molecular structure of polyethylene into a three-dimensional network structure through physical or chemical methods, thereby improving its heat resistance, creep resistance, and mechanical strength.

**The main manufacturing methods for PEX pipe include the Engel process (peroxide process), the silane process, and the radiation process, corresponding to PEX-A, PEX-B, and PEX-C types, respectively.**

The Engel process forms chemical bonds through high temperature and pressure; the silane process mixes silane during extrusion to generate a three-dimensional structure; and the radiation process uses γ or β rays for physical cross-linking. Different types of PEX pipes differ in heat resistance and stress cracking resistance. For example, PEX-A is mainly composed of a two-dimensional network structure, while PEX-B and PEX-C are more heat-resistant due to their three-dimensional structure.

**The main raw material for PEX pipe is high-density polyethylene (HDPE), with added initiators, cross-linking agents, catalysts, and other additives. Modifiers may also be added for special requirements.** 1. Its production process includes raw material pretreatment, mixing, melt grafting extrusion, pipe forming, cross-linking, inspection, and packaging. Additives such as antioxidants can improve corrosion resistance and service life.

PEX pipes have a wide range of applications, mainly including: indoor water supply, hot water and pure water transportation; HVAC systems, underfloor heating and solar water heaters; liquid transportation in the food industry; telecommunications and electrical piping; and pipelines for corrosive chemical media.