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Main Application Areas Of Stainless Steel Welded Pipe

Aug 31, 2020

The main application areas of stainless steel welded pipe are urban landscape and decoration engineering; in light industry, pharmaceuticals, papermaking, sewage treatment, water supply, machinery and other fields, it also has a considerable proportion; in chemical, fertilizer, petrochemical and other industries, the general selection specification is Φ159mm The above medium and low pressure pipelines; stainless steel welded pipes are also used for automobile mufflers.

Stainless steel seamless pipes are mainly used in the "three chemicals" (chemical, fertilizer, chemical fiber), petroleum, electric boilers, machinery, aerospace, nuclear industry, defense industry and other fields.


Oil drill uses stainless steel pipe


Since the 1990s, my country's oil well pipe production capacity has increased year by year, with exports greater than imports, and a self-sufficiency rate of over 90%. However, most of the varieties are medium and low-grade steel grades such as J55 and N80, and only a few API high-grade steel oil well pipes.

At present, APIQ125, C95, L80-2 (13Cr) steel grades with high strength, high resistance to CO2, resistance to Cl-corrosion, and high collapse resistance required by oilfields and special threaded types of non-API standards and cold regions, etc. The oil well pipe used has not yet been industrialized. With the development of the petroleum industry, more and more stringent technical requirements are put forward for oil well pipes. The use of high performance and new materials is the technological development trend of oil well pipes. Stainless steel non-magnetic drill collars, high-resistance CO, CO2 and Cl-corrosion super ferritic stainless steel Cr13, Cr25 and other tubing and casing are used in oilfield drilling and production. According to rough statistical analysis, it currently requires more than 10,000 tons per year. After 3 to 5 years, it will take about 40,000 to 50,000 tons per year. At present, most of such stainless steel pipes still rely on imports.


Stainless steel pipe for thermal power boiler


During the "Eleventh Five-Year Plan" period, approximately 180 million kW of new thermal power will be added, about 40 million kW per year (units of 600,000 kW and above), of which units above supercritical account for more than 50% (using heat-resistant stainless austenitic steel boiler tubes) More). A supercritical thermal power unit boiler of more than 600,000 kW needs to use stainless heat-resistant steel pipes of 200 to 500t, so according to the development plan, about 50,000 tons of stainless heat-resistant steel pipes are needed every year. Newly built 600,000 kW subcritical and supercritical units of the four major domestic boiler plants and stainless heat-resistant steel pipes for power plant maintenance tend to use domestic suppliers. In addition, the domestic consumption of stainless heat-resistant steel pipes for newly built and maintained thermal power boilers is about 12,000 t/a, mainly involving three steel grades TP304H, TP347H, and TP321H. The representative specifications are 38~76mm outer diameter and 4~10mm wall thickness. , The length is greater than 10m. Therefore, stainless heat-resistant steel pipes for thermal power boilers are worthy of vigorous development. As the requirements of supercritical units for high temperature and high pressure increase, the demand for advanced power station boiler tubes TP347HFC, Super304H (1Cr18Ni-9Cu3N), TP310HCbN (1Cr25Ni20NbN), etc. will increase. At present, all such stainless steel pipes rely on imports.


"Sanhua" industrial heat-resistant stainless steel pipe


Heat-resistant stainless steel pipes are mainly used for heat exchange and fluid transportation in the "Sanhua" industry, with the largest market capacity, and the domestic market demand is about 160,000 tons per year. The user's requirements for this type of steel pipe are very high and very strict, and currently they mainly rely on imports. The potential market is large-diameter petroleum cracking furnace pipes and low-temperature conveying pipes. Due to their special heat-resistant and corrosion-resistant requirements and the inconvenience of equipment installation and maintenance, they require a long service life of the equipment and need to optimize the pipes through material composition control and special heat treatment methods. Mechanical properties and use performance. Another potential market is special steel pipes for the chemical fertilizer industry (urea, phosphate fertilizer), the main steel types are 316Lmod and 2re69. At present, the above-mentioned stainless steel pipes basically rely on imports.


The instant electric water heater is mainly composed of a heating trough plate, a pressure sensor, a power regulator, a water volume adjustment faucet, water inlet and outlet pipe components, among which the heating trough is a key component of the instant electric water heater. The heating groove is composed of groove right, sealing ring, cover and electric heating element. The electric heating element is located in the trough of the trough plate, which is generally called the inner tank of the instant water heater. An instant water heater that uses a stainless steel heating tube as the heating body. Cold water enters the inner tank and flows directly through the surface of the stainless steel electric heating tube to be heated. Stainless steel electric heating tube is currently the most used heating method in the instant electric water heater industry.

The advantages of stainless steel heating tube are: better heat resistance, dry burning resistance, mature technology, and lower cost. At present, there are many types of stainless steel heating pipes used by the manufacturers of instant electric water heaters, and the price gap of various pipes is large. The same is the stainless steel electric heating tube, the difference in quality and performance is also very large. The difference between the quality of stainless steel electric heating pipes is mainly the difference in nickel content. Nickel is an excellent corrosion-resistant material. After being combined with chromium in stainless steel, the corrosion resistance and process performance of stainless steel can be improved. However, for low-carbon nickel steel to obtain pure austenitic structure, the nickel content must reach 24%, and only when the nickel content is 27% can the corrosion resistance of the steel in certain media be significantly changed. Therefore, 800, 840, and 316L are relatively good corrosion-resistant and high-temperature resistant stainless steel electric heating tubes in terms of materials. The 800 stainless steel tube contains 30% nickel, and the 840 tube contains 20% nickel. Some 304 stainless steel tubes contain only 8% nickel. Therefore, the use of high temperature and corrosion resistant stainless steel heating tubes with high nickel content is also very advantageous.