What tests need to be conducted on plastic-lined composite pipes?

Firstly, a dimensional inspection is required. Additionally, plastic-lined composite pipes must not exhibit any issues such as diameter reduction or pipe shrinkage. An appearance inspection should confirm that the surface is smooth, the color is uniform, there are no cracks or bubbles, there are no scratch defects that significantly affect the appearance, there is no exposure of the metal substrate, and the weld seam surface is smooth and even. A groove inspection and a spray code inspection are also necessary. Furthermore, tests for bond strength, bending performance, flattening performance, resistance to hot and cold cycling, and hygienic performance should be conducted.