Seamless tube for boiler is a kind of boiler tube, which belongs to the category of seamless steel tube. The manufacturing method is the same as seamless tube, but there are strict requirements on the steel used in the manufacture of steel tube. Boiler with seamless tube is often used in high temperature and high pressure conditions, pipes in high temperature flue gas and water vapor under the action, will occur oxidation and corrosion. Steel tubes are required to have high durable strength, high oxidation corrosion resistance, and good tissue stability. Boiler with seamless tube is mainly used to manufacture high pressure and ultra-high pressure boiler superheater tube, reheater tube, gas guide boiler with seamless tube, the main steam tube, etc.

Low and medium pressure boiler tube GB3087-1999, boiler seamless tube GB5310-1999 is used to manufacture a variety of structures of low pressure boiler superheated steam pipe, boiling water pipe and locomotive boiler superheated steam pipe, smoke pipe, small smoke pipe and arch brick pipe pipe of high quality carbon structural steel hot rolled and cold drawn (rolled) seamless steel pipe. Seamless steel tube for structure (GB/T8162-1999) is a seamless steel tube for general structure and mechanical structure. Specifications and appearance quality: GB5310-95 “Seamless Steel tube for High pressure boiler” hot rolled pipe diameter 22~530mm, wall thickness 20~70mm. The outer diameter of cold drawn (cold rolled) tube is 10~108mm, and the wall thickness is 2.0~13.0mm. Special shaped seamless steel pipe is a general term for seamless steel pipe of other cross section shapes except round pipe. According to the different shape and size of steel pipe section, it can be divided into equal wall thickness special-shaped seamless steel pipe (code for D), unequal wall thickness special-shaped seamless steel pipe (code for BD), variable diameter special-shaped seamless steel pipe (code for BJ). Special shaped seamless steel tubes are widely used in various structural parts, tools and mechanical parts. Compared with the round tube, the special-shaped tube generally has a larger moment of inertia and section modulus, and has a greater ability to resist bending and torsion, which can greatly reduce the weight of the structure and save steel. 4. Chemical composition test (1)GB3087-82 “seamless steel tube for low and medium pressure boiler” provisions. Chemical composition test method according to GB222-84 and GB223 “Steel and Alloy Chemical Analysis Method” the relevant part. (2)GB5310-95 “Seamless Steel Tube for High pressure boiler” provisions. The test method of chemical composition is in accordance with the relevant parts of GB222-84, Chemical Analysis Method of Steel and Alloy, and GB223 Chemical Analysis Method of Steel and Alloy. (3) The chemical composition inspection of imported boiler steel tubes shall be carried out according to the relevant standards stipulated in the contract. 5 boiler with seamless tube steel (1) high quality carbon structural steel steel is 20G,20MnG, 25MnG.(2) alloy structural steel steel 15MoG, 20MoG, 12CrMoG, 15CrMoG, 12Cr2MoG12CrMoVG, 12Cr3MoVSiTiB and so on. (3) rust heat resistant steel commonly used 1Cr18Ni9, 1Cr18Ni11Nb boiler tube in addition to ensure chemical composition and mechanical properties, to do hydraulic test root by root, to do flaring, flattening test. Steel tubes are delivered in a heat treated state. In addition, the microstructure, grain size and decarbonization layer of the finished steel pipe are also required.

6. Physical performance test(1)GB3087-82 “Seamless steel tube for low and medium pressure boiler” provisions. Tensile test according to GB/T228-87, hydraulic test according to GB/T241-90, squashing test according to GB/T246-97, flaring test according to GB/T242-97, cold bending test according to GB24497(2)GB5310-95 “Seamless Steel Tube for High pressure boiler” provisions. Tensile test, hydrostatic test and flattening test are the same as GB3087-82; Impact test according to GB229-94, flaring test according to GB/T242-97, grain size test according to YB/T5148-93; According to GB13298-91 for microscopic tissue examination, GB224-87 for decarbonized layer examination, and according to GB224-87 for ultrasonic examinationGB/T5777-96.(3) The physical performance inspection and indexes of imported boiler tubes shall be carried out according to the relevant standards stipulated in the contract.

7. Main import and export situation

(1) high pressure boiler seamless tube major importing countries are Japan, Germany. Often import the specifications of the 15914.2 mm;2734.0 mm; 219.110.0 mm; 41975mm; 406.460 mm, etc. Minimum specification is 31.84.5 mm, length is usually 5 ~ 8 m.(2) in the case of the imported claim, Germany mannesmann seamless boiler tube, pipe mill imported ST45 by ultrasonic testing of census, found that a small number of internal defects of steel pipe more than the factory regulations and German steel association standards.(3) from Germany imported alloy steel pipe, steel grade are 34 crmo4 and 12 crmov, etc. This kind of steel tube high temperature performance is good, commonly used for high temperature boiler steel pipe.(4) alloy tube imported from Japan more, specifications mm5 426.012 ~ 8 m; 152.48.0 mm12m;89.110.0 mm6m; 101.610.0 mm12m; 114.38.0 mm6m; 127.08.0 mm9m JISG3458 implementation of the Japanese industrial standard, such as steel grade for STPA25, this kind of steel pipe used for matching with high temperature alloy tube.High pressure boiler seamless tube import and export,(1) high pressure boiler seamless tube major importing countries are Japan, Germany. Often import the specifications of the 15914.2 mm;2734.0 mm; 219.110.0 mm; 41975mm; 406.460 mm is the smallest specifications such as 31.84.5 mm, length is usually 5 ~ 8 m.(2) in the case of the imported claim, Germany mannesmann seamless boiler tube, pipe mill imported ST45 by ultrasonic testing of census, found that a small number of internal defects of steel pipe more than the factory regulations and German steel association standards.(3) from Germany imported alloy steel pipe, steel grade are 34 crmo4 and 12 crmov, etc. This kind of steel tube high temperature performance is good, commonly used for high temperature boiler steel pipe.(4) alloy tube imported from Japan more, specifications mm5 426.012 ~ 8 m; 152.48.0 mm12m;89.110.0 mm6m; 101.610.0 mm12m; 114.38.0 mm6m; 127.08.0 mm9m JISG3458 implementation of the Japanese industrial standard, such as steel grade for STPA25. This kind of steel pipe used for matching with high temperature alloy tube.

The boiler seamless tube production methodsThe boiler with a kind of seamless tube. Manufacturing methods and seamless tube are the same, but have strict request for manufacturing steel used in the steel pipe. According to the use of temperature can be divided into two general boiler tube and high pressure boiler tube.1, an overview of the(1) manufacturing method:(1) general boiler seamless tube temperature under 450 ℃, the domestic pipe mainly use 10, 20 carbon steel hot rolled or cold drawn tube manufacture.(2) high pressure boiler seamless tubes are often in high temperature and high pressure conditions, when using the pipe under the action of high temperature flue gas and water vapor, oxidation and corrosion will happen. Requirements of steel pipe with high rupture strength, high oxidation corrosion resistance, and have good organizational stability.(2) use:(1) general boiler seamless tube is mainly used to make water wall tube, water pipe, superheated steam tube, locomotive boiler superheated steam pipe, large and small pipe and tube arch brick, etc.(2) high pressure boiler seamless tube is mainly used to manufacture high-pressure and ultrahigh-pressure boiler superheater tubes, reheater tube, airway main steam pipe, etc.

Use of boiler seamless tube

(1) general boiler seamless tube is mainly used to make water wall tube, water pipe, superheated steam tube, locomotive boiler superheated steam pipe, large and small pipe and tube arch brick, etc.(2) high pressure boiler seamless tube is mainly used to manufacture high-pressure and ultrahigh-pressure boiler superheater tubes, reheater tube, airway main steam pipe, etc.(3) GB3087-82 low medium pressure boiler seamless steel tubes and GB5310-95 “high pressure boiler seamless steel tube” regulation. Appearance quality: steel tube inside and outside surface are not allowed to have a crack, folding, folding, scarring, delamination and hairline. These defects shall be completely removed. Remove negative deviation, depth shall not exceed the nominal wall thickness the cleaning in the actual wall thickness shall not be less than the minimum value of wall thickness is allowed.Weight calculation method of boiler seamless tube theory: – wall thickness (diameter) * 0.02466 * wall thickness.