Boiler tube

Boiler tube

Boiler tube is a kind of seamless tube. The manufacturing method is the same as that of seamless tube, but there are strict requirements on the type of steel used to manufacture steel tube. According to the use temperature, it is divided into general boiler tube and high-pressure boiler tube.
The mechanical properties of boiler tube are important indicators to ensure the final use performance (mechanical properties) of steel, which depends on the chemical composition and heat treatment system of steel. In the steel tube standard, according to different use requirements, tensile properties (tensile strength, yield strength or yield point, elongation) and hardness, toughness indicators, as well as high and low temperature properties required by users are specified.

① The use temperature of general boiler tubes is below 350℃, and domestic tubes are mainly made of No. 10 and No. 20 carbon steel hot-rolled tubes or cold-drawn tubes.
② High-pressure boiler tubes are often in high temperature and high pressure conditions during use. Under the action of high-temperature flue gas and water vapor, the tubes will oxidize and corrode. Steel pipes are required to have high lasting strength, high anti-oxidation and corrosion performance, and good organizational stability.
Uses
① General boiler tubes are mainly used to manufacture water-cooled wall tubes, boiling water tubes, superheated steam tubes, superheated steam tubes for locomotive boilers, large and small smoke tubes and arch brick tubes, etc.
② High-pressure boiler tubes are mainly used to manufacture superheater tubes, reheater tubes, gas guide tubes, main steam tubes, etc. for high-pressure and ultra-high-pressure boilers. The supply and demand trend of the high-pressure boiler tube industry is generally stable, but the supply and demand situation of each specific sub-industry will further differentiate. Industry insiders pointed out that the most critical link is the use and promotion of new energy-saving and heat-insulating 20g high-pressure boiler tube equipment.
New energy-saving 20g high-pressure boiler tube products are gradually increasing in the market, such as green environmental protection coatings, energy-saving and water-saving sanitary products, environmental protection stone, environmental protection external cement foam insulation board, etc. The prospects of energy-saving and environmental protection products in the vast market of 20g high-pressure boiler tube industry are promising.
Related regulations
(1) GB/T5310-2008 “Seamless Steel Tubes for High-Pressure Boilers” stipulates. The chemical composition test method shall be in accordance with the relevant parts of GB222-84 and “Methods for Chemical Analysis of Steel and Alloys” and GB223 “Methods for Chemical Analysis of Steel and Alloys”.
(2) The chemical composition test of imported boiler steel pipes shall be carried out in accordance with the relevant standards stipulated in the contract.
Steel grades used
(1) High-quality carbon structural steel grades include 20G, 20MnG, and 25MnG.
(2) Alloy structural steel grades include 15MoG, 20MoG, 12CrMoG, 15CrMoG, 12Cr2MoG, 12CrMoVG, 12Cr3MoVSiTiB, etc.
(3) Rust-resistant heat-resistant steels such as 1Cr18Ni9 and 1Cr18Ni11Nb boiler pipes shall be subjected to water pressure tests, expansion and flattening tests in addition to ensuring the chemical composition and mechanical properties. Steel pipes are delivered in a heat-treated state.
In addition, there are certain requirements for the microstructure, grain size, and decarburized layer of the finished steel pipes.