The manufacturing process of internally and externally plastic-coated composite steel pipes is not much different from that of other plastic-coated steel pipes. The difference may lie in the coating material required by the customer, which will vary depending on the customer’s specifications. In current home decoration processes, how should one choose plastic-coated steel pipes? How can one judge the quality of plastic-coated steel pipes? This article compiles the secrets to selecting and identifying the quality of steel-plastic composite pipes. Plastic-coated steel pipes are also used in the chemical industry, including the transportation of various chemical liquids, and can also be used as ventilation pipes in mines and shafts.
It’s necessary to understand the forming method of producing plastic-coated steel pipes. Centrifugal casting is a fixed-length method: In this process, cut glass fiber reinforcement and sand are fed into a steel mold fixed to a bearing. Unsaturated resin with a catalyst is injected into one end of the mold, impregnating the reinforcement. Under centrifugal force, the resin displaces air from the fibers and fillers, creating a dense, non-porous composite material. Due to centrifugal force, a smooth, glossy, resin-rich inner surface layer is formed on the inner wall of the plastic-coated steel pipe. The pipe cures at a high temperature.
However, what are the characteristics of internally and externally plastic-coated composite steel pipes? Data shows that in the first half of the year, China reduced steel production capacity by more than 100 million tons, achieving approximately 0% of this year’s target. If defects are found, they are automatically marked, allowing production workers to adjust process parameters promptly. Plastic-coated steel pipes should have clear and durable markings, including at least: product model, base pipe specifications and wall thickness, applicable standards, manufacturer’s name or trademark, and production date or batch number. After all, the drilling operations for this type of pipe are quite demanding, which makes the pipe very rough and uneven, significantly impacting its usability.
Scrap metal coated steel pipes are further divided into internal and external scrap. Based on the strength of the steel itself, the casing can be classified into different steel grades, namely J, K, N, L, C, T, P, Q, V, etc. If defects appear on the weld surface, there is a possibility of defects inside the weld. It can be seen that the development of plastic-coated steel pipes is a spiral-like process. The service life of plastic-coated steel pipes is expected to decrease slightly. Poor quality deoxidizer, insufficient dosage, or improper operation… In recent years, the application fields of plastic-coated steel pipes have become increasingly wider.
Plastic-coated steel pipe products are categorized as follows: water supply plastic-coated steel pipes, central air conditioning and HVAC circulating water plastic-coated steel pipes, fire-fighting plastic-coated steel pipes, anti-corrosion plastic-coated steel pipes, gas plastic-coated steel pipes, etc. These products are used across various diameter ranges in daily life. DN15-DN hot-dip plastic-coated steel pipes have extremely strong coating adhesion. After internal sandblasting and external shot blasting surface treatments, the contact area between the steel pipe surface and the coating is increased, resulting in superior adhesion. Generally, low-pressure fluid transportation uses spiral double-sided submerged arc welded steel pipes, manufactured using double-sided automatic submerged arc welding or single-sided welding, for water, gas, air, steam, building piling, and low-pressure pipeline transportation.
Spiral steel pipes generally have higher strength than straight seam welded pipes. They can be produced from narrower blanks to create larger diameter welded pipes, and can also be produced from blanks of the same width to create welded pipes of different diameters. It’s important to know the forming methods for producing plastic-coated steel pipes. These methods include: UOE method, CFE roller forming method, RBE roller bending method, JCOE forming method, C forming method, and PFP progressive bending method. Externally galvanized and internally plastic-coated composite steel pipes (steel-plastic composite pipes) use galvanized steel pipes as the base pipe. The inner wall of the galvanized steel pipe is coated with high-adhesion, corrosion-resistant, food-grade hygienic polyethylene powder coating or epoxy resin coating. It can achieve a lifespan of up to 8 years. 8mm reinforced type, smaller than 5mm. The adhesion of the coating to the substrate is an important indicator for evaluating the coating’s corrosion resistance. Plastic-coated steel pipe manufacturers understand that pickling: Commonly, pickling is done using chemical and electrolytic methods. Pipeline corrosion protection only uses chemical pickling, which can remove oxide scale, rust, and old coatings. Sometimes it can be used as a post-treatment after sandblasting.
Post time: Apr-20-2026