Plastic-Lined Steel Pipe Workshop
This plastic-lined steel pipe workshop specializes in lining pipes from 2 to 48 inches in diameter by inserting and bonding a seamless thermoplastic liner to the internal surface. Utilizing key processes like rotational molding (rotolining) and pull-in (swage-lining), we supply integrated solutions for the complete production sequence—including pipe preparation, liner forming, bonding, testing, and finishing. Our production ensures medium-to-high volume output of pipes with a uniform, void-free liner, excellent chemical resistance, and reliable adherence to dimensional standards for demanding fluid transport applications.
Workshop
Production Equipment
![Finishing Machine]()
Finishing Machine![Expanding Machine]()
Expanding Machine![Three Wire Internal Welding Machine]()
Three Wire Internal Welding Machine![Steel Plate Pre Bending Machine]()
Steel Plate Pre Bending Machine![Four Wire Internal Welding Machine]()
Four Wire Internal Welding Machine![Forming Machine]()
Forming Machine
Manufacturing Process
Manufacturing Process of Plastic-Lined Steel Pipe
The manufacturing process of plastic-lined steel pipe involves several key stages to ensure a durable, corrosion-resistant final product. It begins with pipe preparation, where the steel pipe's interior is thoroughly cleaned and grit-blasted to achieve a specific surface profile, promoting optimal mechanical adhesion.
The core lining application primarily uses the rotational lining (rotolining) method: thermoplastic resin powder is placed inside the pipe, which is then rotated and heated in an oven. The powder melts and fuses to form a seamless, uniform liner that conforms to the pipe's interior geometry. Finally, the pipe undergoes controlled cooling and rigorous inspection & testing, including spark (holiday) detection and dimensional checks, to validate liner integrity, thickness, and bond quality before the pipe ends are finished for installation.
Inspection Center
Union Steel established the Inspection Center and equipped with advanced experimental testing equipment. Union Steel Tube Inspection Center has passed the assessment of China National Accreditation Committee for Conformity Assessment and successfully obtained the CNAS laboratory certification. The test results of the test and inspection center are mutually recognized with 35 quality management system certification and environmental management system certification and accreditation bodies and 54 laboratory accreditation bodies in other countries and regions, which fully demonstrates the authority of the testing activities of Union Steel pipe inspection center.
ERW Pipe Inspection Line
In order to ensure that the steel pipes we produce meet the standard requirements, the quality engineers, on-site inspection personnel and front-line production workers of Union Steel need to make great efforts. During the production process, we will conduct the following inspections and tests on steel pipes according to standard requirements:
Tensile Test, Metallographic Test, Charpy Impact Test, Spectral Analysis, Drop Weight Tear Test, Flattening Test, Hydrostatic Test, NDT Non Destructive Test
