Probe into the selection of thin-walled stainless steel pipes fittings and stainless steel pipes

Probe into the selection of thin-walled stainless steel pipes fittings and stainless steel pipes

Based on the analysis of the product characteristics of stainless steel pipes, this paper comprehensively analyzes the matters needing attention in the selection of thin-walled stainless steel pipes and pipe fittings. At the same time, it deeply analyzes the domestic development prospects of thin-walled stainless steel materials and the technical problems that need to be solved in the development process.

Thin-walled stainless steel pipe and stainless steel pipe fittings as one of the important products of the development of modern material science, because of its own beautiful appearance, and corrosion resistance and durability have greater advantages, belonging to the energy-saving and environmentally friendly products, has been widely used in domestic and foreign construction projects. At present, the thin-walled stainless steel pipe connection has a variety of types of compression stainless steel fittings, and in the installation has a more convenient safety and reliability characteristics, significantly reducing the wall thickness cost, in the future there are more extensive application prospects.

1. Stainless steel pipe, stainless steel pipe fittings product characteristics

Stainless steel pipe even after long-term use, its anti-scaling performance is still excellent, in which the transported water quality can meet the current health standards requirements. At the same time, stainless steel pipe after solid solution treatment, its surface pickling passivation treatment, can effectively improve its corrosion resistance, its durability will also be greatly enhanced. In addition, the relevant tests have proved that the bonding strength of stainless steel pipes and stainless steel fittings is twice that of galvanized pipes, three times that of copper pipes, but its weight is only 1/3 of galvanized pipes, so stainless steel pipes and stainless steel fittings are very suitable for the construction of pipeline projects in high-rise buildings. At the same time, stainless steel pipe itself has a greater advantage in the thermal conductivity, its thermal conductivity is only 1/25 of copper pipe, the impact of thermal expansion and contraction is relatively small, and in the process of construction of stainless steel pipe can be used in the premise of not producing any pollutants, to minimize the impact of construction on the environment, all these advantages are not available in other types of pipe. Stainless steel surface there is a thin but strong oxide film, stainless steel in any water quality has a high corrosion resistance, even if it is buried underground can also have a relatively good corrosion resistance. Because stainless steel pipe and stainless steel pipe fittings have the above excellent product characteristics, so you can greatly reduce the thick wall and installation and transportation costs. When used in the water industry, it is suitable for a variety of water quality and does not produce corrosion and exudate problems. In addition, stainless steel pipe can accept a speed of up to 30m / s high-speed water wash, even in the high-speed hydroelectric power station inflow stainless steel pipe, stainless steel pipe pipe end of the water velocity up to 60m / s, its service life can still be maintained in about 100 years, and does not require secondary coating protection.

2. Thin-walled stainless steel pipe and stainless steel pipe fittings need to pay attention to the point of selection

2.1 Pipe diameter and connection form

Stainless steel pipe is the main pipe of the current water supply pipeline. In indoor buildings, especially in high-rise construction projects, most of the leakage phenomenon occurs in the water supply pipe connection position, although the continuous development of current metal material technology has given rise to many new pipes, but some of the pipes and stainless steel fittings can be applied or not is still debatable. Some of the connections are suitable for smaller diameter pipes, but problems can arise in larger diameter pipes. For example, the most suitable connection method for pipes with a diameter of more than 70mm is welding or flange, while the best connection method for pipes with a diameter of less than 70mm is hinging. At the same time, the material selection is reasonable or not will have a direct impact on the service life and cost of the pipe, stainless steel fittings.

2.2 Flexibility of the expansion of the pipe

Everything is in a state of constant motion, the pipeline in the water supply and drainage engineering applications, often because of the impact of construction vibration, water impact and other factors, there is a certain degree of expansion and deformation. Therefore, in the selection of thin-walled stainless steel pipe, stainless steel pipe fittings, the need to fully consider the pipe, stainless steel pipe fittings connected to the location of the expansion and flexibilities. From the relevant research results, it seems that the plastic pipe because of its own flexibility is relatively high, so the expansion and flexibilities do not have any problems. At the same time, the copper pipe is rigid sealing method, basically does not have the expansion and flexibility. Although the thin-walled stainless steel pipe, stainless steel pipe fittings and its connection is also rigid, but it can be used with its matching expansion and flexibility joints, with good expansion and flexibility, and the possibility of loosening and leakage of its connection position is also significantly reduced.

2.3 Impact resistance and pull-out force of the pipe

The current high-rise building presents a large-scale development trend, such as a 30-story building, its height can reach about 100m, in the water filled with the entire water pipe, its pressure value will reach 10MPa. but most of the current construction projects are using the frequency conversion mode, the water pressure value can not always be guaranteed. Therefore, in the selection of thin-walled stainless steel pipe, stainless steel pipe fittings, it is necessary to consider the impact pressure value of the two connection locations. According to the current experimental and research data, thin-walled stainless steel pipe, stainless steel pipe fittings, impact resistance is the most excellent, such as other stainless steel composite pipe, aluminum composite pipe and other tubes in the same water pressure impact value are serious leakage problems. In addition, the production of pipes, stainless steel fittings, as long as the production process is fully followed, the strength and damage tests implemented on both individually will not be a problem. But in the case of the two connected together, the location of the two connections is the weakest place. For this reason, in the selection of stainless steel pipe, stainless steel fittings, the need for the two connection location of the pull-out force test, to ensure that the connection location using the connection method can meet the actual needs of the project.

2.4 The twist of the pipe

In the process of construction, construction workers are often affected by the construction site, space and other factors often ignore the requirements of construction specifications with the help of pipe plasticity. In this case, the selection of thin-walled stainless steel pipe, stainless steel fittings need to consider the twist of the two connection positions. For this reason, in the selection of thin-walled stainless steel pipe, stainless steel fittings, the need to engineering in pressure and other aspects of the requirements as the basis for the joint and pipe in constant pressure conditions for torsion test, so as to ensure that the thin-walled stainless steel pipe, stainless steel fittings twist in line with engineering construction requirements.

3. Stainless steel pipe, stainless steel pipe fittings in the domestic application prospects

Construction industry projection data show that China’s annual demand for pipes is maintained at about 500,000km-60 millionkm, which residential building indoor hot and cold water pipe demand reached 400,000km. and stainless steel pipe, stainless steel pipe fittings because of its own good resistance to scouring and corrosion resistance can be widely used in the construction of hot and cold water pipe construction, and in the future China In the process of rapid development of urbanization in China, stainless steel pipe and stainless steel pipe fittings will be further promoted in the scope of application. In addition, the current domestic first-tier cities began to promote the pipeline direct drinking water, and in the choice of direct drinking water pipeline, stainless steel pipe is undoubtedly the first choice, mainly because the stainless steel pipe in the process of transporting water does not produce any corrosion and exudate problems, will not have any adverse impact on the quality of tap water, for the further popularization of the development and application of stainless steel pipe provides the basis of the social environment. At the same time, although China started relatively late in the research of stainless steel pipe, but after decades of development, the quality of China’s stainless steel pipe, stainless steel fittings can already be compared with internationally renowned brands, and the current domestic construction pipeline basically began to choose the domestic stainless steel pipe, under the influence of China’s continuous development of material science and technology, thin-walled stainless steel pipe, stainless steel fittings quality and type will also gradually Improve and enrich. 4.

4. China’s stainless steel pipe, stainless steel pipe fittings need to solve the problem of development

4.1 Price problem

Stainless steel pipe, stainless steel fittings in the process of popularization and development need to solve the first problem is the price. The price of stainless steel tubes and copper tubes belong to the same level, and the price of the stainless steel tube itself is more closely related to its wall thickness, which is also the main reason why the current thin-walled stainless steel tube R & D applications to pay attention to. The development of thin-walled stainless steel tube greatly reduces the production cost of the product, for the further popularization of stainless steel tube in daily life to provide the conditions for application. Some people currently believe that the price of stainless steel in a higher state, in fact, from the essence of the home construction of water pipes and connections to maintain the metal materials price of about 1500 yuan -2000 yuan, compared to the current high quality aluminum composite pipe and PP-R plastic pipe market price is about 10%-15% higher, but lower than the thin-walled copper pipe prices. But the people’s income level and quality of life conditions to measure, the price is completely acceptable. It should also be noted that, in the entire home renovation project costs, the proportion of pipe costs remain at 3%-5%, but the use of thin-walled stainless steel pipe, to eliminate the other pipes may bring leakage and corrosion and many other problems. With today’s continuous development of material science and technology, the application of thin-walled stainless steel pipe is a good solution to the price of stainless steel material controversy.

4.2 Connection problems

Stainless steel pipe, stainless steel fittings application development needs to solve another problem is the technical connection, mainly because the connection of stainless steel pipe has a decisive impact on its economy and reliability. In the current development of stainless steel pipe, stainless steel fittings, compression, compression, flange connection, etc. are the most common connection of stainless steel pipe. These connections are different because of the principle level, resulting in its actual use of the scope of each focus, but the vast majority of them are more convenient and reliable in the installation work. In the connection of thin-walled stainless steel pipe used in the seal material are in line with the current national standard requirements of silicone rubber, nitrile rubber, etc., well reduce the incidence of leakage problems in the use of the pipeline. But the point to note is that the current domestic manufacturers of thin-walled stainless steel pipe in the connection of a large difference in the way, resulting in thin-walled stainless steel pipe overall after-sales service level does not keep up with the trend of development. Although the current thin-walled stainless steel technology has been a huge development in the connection method, but the market share is still low.

5. Summary

The application of thin-walled stainless steel pipe, in reducing the price of stainless steel products at the same time, to ensure a higher resistance to scouring and corrosion resistance, compared with other metal materials of the pipe, in the thermal conductivity, weight and other aspects also has a greater advantage, worthy of a wide range of applications in many fields such as construction.
Source:  China Pipe Fittings Manufacturer – Yaang Pipe Industry Co., Limited (www.pipelinedubai.com)