Comparison of the advantages and disadvantages of stainless steel pipes and plastic-lined steel pipes

In the use of pipes, plastic-lined steel pipes and stainless steel pipes are relatively common. Their performance is outstanding and each has its own merits. The advantages and disadvantages of the two will be described in detail below.
Plastic-lined steel pipe is a composite pipe made by lining plastic pipes inside steel pipes through tight lining composite technology. It not only has the characteristics of high strength and high pressure resistance of steel pipes, but also has the characteristics of plastic pipes that are not prone to scaling, corrosion resistance, smooth inner wall, low flow resistance, and difficult to breed microorganisms. However, its disadvantages are that it is heavier and is not suitable for long-term storage in the open air. It has poor weldability during installation and needs to be kept away from fire sources.
Stainless steel pipes are usually thin-walled pipes with beautiful appearance, clean and hygienic and high corrosion resistance. The inner wall of the pipe is smooth and light in weight. However, the disadvantage of stainless steel pipes is that the pipe wall is thin. When installing and cutting pipes, it is easy to produce oval openings, making the joints easy to seep. When encountering continuous impact from external forces, it is easy to have dents and scratches. This kind of defect is difficult to repair, and it is difficult to construct during installation. It is also higher, so the overall price is relatively more expensive.
In terms of connection methods, plastic-lined steel pipes usually adopt three types: threaded connection, flange connection and groove connection. Threaded connections and flange connections have been used a hundred years ago. Their technical content is relatively low, ordinary workers can operate them without technical training, and they are relatively safe and reliable methods. The special tight lining process solves the problems of plastic cracking, steel-plastic separation and degumming that occur during groove connection. When connecting to the pipe fitting, in addition to releasing the raw material tape at the thread to form a seal, a silicone rubber gasket must be placed inside the injection molded pipe fitting to keep the end face of the pipe mouth and the plastic-lined root of the pipe fitting sealed, completely isolating the metal and the medium, so as to completely solve the internal problem. Resistant to corrosion issues, thereby ensuring media quality.
Stainless steel pipe connections usually use a compression socket connection. This connection method has relatively high requirements for operators, and the operators must undergo strict special training in advance. If the operator cannot press the calipers at a 90° right angle to the axis of the connection between the pipe and fittings, it will not ensure that the outer wall of the stainless steel pipe is pressed against the axis at the same time, which will cause the pipe diameter ellipse to be staggered, making the gap easy to leak. In more serious cases, the sealing ring will be squeezed out laterally, causing serious water leakage.
In terms of use, plastic-lined steel pipes are suitable for transporting ordinary corrosive liquids or solid media. They are more suitable for domestic water and drinking hot and cold water. They will not affect water quality when transporting water. They can meet food hygiene requirements and are also suitable for reclaimed water. , rainwater, gas, chemical industry, food, pharmaceutical, electric power, sanitation, fire protection, coal mining and HVAC and other fields. Stainless steel pipes are usually used as stainless heat-resistant steel, mainly used in chemical industry and domestic water, weak acid and alkaline fluid medium transportation, etc. Regarding hygienic performance, stainless steel pipes and plastic-lined steel pipes fully comply with food hygiene requirements.