Advantages and Installation Points of Commonly Used Plastic-Coated Steel Pipes in Industry

Plastic-coated steel pipes, also known as plastic-coated pipes, steel-plastic composite pipes, or plastic-coated composite steel pipes, are steel-plastic composite pipes with a steel pipe base. A layer of plastic anti-corrosion coating is fused to the inner surface of the steel pipe (base pipe) or to both the inner and outer surfaces through spraying, rolling, dipping, or suction processes. Plastic-coated steel pipes use ordinary carbon steel pipes as the base pipe, with both the inner and outer walls coated with a thermoplastic with excellent chemical stability. They are specialized chemical composite pipes that have undergone anti-corrosion processing, effectively preventing corrosion from acids, alkalis, and salts in chemical fluids. Previously, chemical pipes were highly susceptible to corrosion, requiring annual replacement and resulting in very high maintenance costs. This product addresses these shortcomings, extending its service life to 20 years. Chemical pipelines are often buried underground, and older pipelines couldn't withstand the harsh environments of underground use, accelerating the aging of previous generations and even causing leaks. Plastic-coated steel pipes for chemical applications have changed this situation, leading to their increasing popularity among chemical plants and becoming a preferred piping material in the chemical industry.

First, Advantages of Plastic-Coated Steel Pipes:

1. Hygienic and non-toxic, it does not accumulate scale or breed microorganisms, ensuring fluid quality.

2. Resistant to chemical corrosion, soil and marine organism corrosion, and cathodic disbondment.

3. Mature, convenient, and quick installation process, similar to connecting ordinary galvanized steel pipes.

4. Good weather resistance, suitable for harsh environments such as deserts and saline-alkali lands.

5. Smooth pipe wall, improving transport efficiency and extending service life.

Second, Key Points for Construction and Installation of Plastic-Coated Steel Pipes:

1. Installation should comply with the "Technical Specification for Plastic-Coated Composite Pipe Engineering for Building Water Supply" CECS125:2001.

2. The following construction tools should be used for plastic-coated steel pipes:

(1) Cutting should be done with a metal saw.

(2) Grooving should be done with a dedicated grooving machine.

(3) Bending should be done with a pipe-bending machine for cold bending.

(4) Threading should be done with an electric threading machine.

(5) Deburring and rounding the ends of the plastic-coated steel pipes should be done with a file.

(6) Applying high-strength inorganic solvent liquid epoxy resin coating should be done with a small brush or a small toothbrush.

3. The construction procedure for plastic-coated steel pipes shall meet the following requirements:

(1) Plastic-coated steel pipes should not be buried in reinforced concrete structural layers;

(2) Welding is prohibited during the installation of plastic-coated steel pipes;

(3) The installation of plastic-coated steel pipes should proceed gradually from large diameter to small diameter, and the pipe ends should be sealed in a timely manner.

(4) During transportation, loading and unloading, and on-site construction, plastic-coated steel pipes must not be thrown or subjected to violent impacts;

(5) When installing plastic-coated steel pipes, if the pipe diameter is not greater than DN50, a pipe bending machine can be used for cold bending, but the bending radius shall not be less than 8 times the pipe diameter, and the bending angle shall not be greater than 10°.

Third, Installation Method of Plastic-Coated Steel Pipes

1.  Pipe Cutting: Calculate the pipe dimensions, use a special pipe cutting tool to cut the steel pipe to the required length, and keep the pipe end perpendicular to the axis of the stainless steel pipe during cutting.

2. Cleaning and Adhesive Application: Clean the stainless steel pipe fitting socket and the end of the thin-walled stainless steel pipe, ensuring there is no water, oil, or other foreign matter present. Then, evenly apply anaerobic adhesive 5mm from the end of the pipe to the marked line.

3. Pipe Insertion: Insert the stainless steel water pipe into the bottom of the fitting socket and rotate it once to ensure even adhesive adhesion.

4. Crimping: Place the steel pipe into the crimping die of the crimping tool and then crimp it.