3LPE coating, or three-layer polyethylene coating, is a multi-layer anti-corrosion coating system used on steel pipes, particularly for oil and gas pipelines. It provides excellent protection against corrosion, mechanical damage, and cathodic disbondment. The three layers consist of a fusion-bonded epoxy (FBE) primer, a copolymer adhesive, and an outer layer of polyethylene. 

3LPE coatings are widely used in the oil and gas industry for pipelines that transport crude oil, natural gas, and other fluids. They are also used in other applications where corrosion protection and mechanical strength are important, such as water pipelines and industrial piping systems.