Boiler tube
Boiler tube is a kind of seamless tube. The manufacturing method is the same as that of seamless pipe, but there are strict requirements for the steel grade used in the manufacture of steel pipe. According to the service temperature, it is divided into general boiler tube and high-pressure boiler tube. The mechanical property of boiler tube is an important index to ensure the final service performance (mechanical property) of steel, which depends on the chemical composition and heat treatment system of steel. In the steel pipe standard, according to different service requirements, the tensile properties (tensile strength, yield strength or yield point, elongation), hardness and toughness indexes, as well as the high and low temperature properties required by users are specified. ① Generally, the service temperature of boiler tubes is below 350 ℃, and domestic tubes are mainly made of No. 10 and No. 20 carbon structure steel hot-rolled tubes or cold drawn tubes. ② High pressure boiler tubes are often in high temperature and high pressure conditions. The tubes will be oxidized and corroded under the action of high temperature flue gas and steam. The steel pipe is required to have high lasting strength, high anti-oxidation and corrosion performance and good structural stability. ① General boiler tubes are mainly used to manufacture water wall tubes, boiling water tubes, superheated steam tubes, superheated steam tubes for locomotive boilers, large and small smoke tubes and arch brick tubes. ② High pressure boiler tubes are mainly used to manufacture superheater tubes, reheater tubes, air ducts, main steam tubes, etc. of high-pressure and ultra-high-pressure boilers. The supply and demand trend of high-pressure boiler tube industry is generally stable, but the supply and demand situation of each specific sub industry will be further differentiated. Insiders pointed out that the most critical link is the use and promotion of new energy-saving and thermal insulation 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 stones, environmental protection external cement foam insulation board, etc. the prospect of energy-saving and environmental protection products in the broad market of 20g high-pressure boiler tube industry is promising[ 1]Medium and low pressure boiler tubes
Medium and low pressure boiler tubes are high-quality carbon structural steel hot-rolled and cold drawn (rolled) seamless tubes used to create superheated steam tubes, rolling tubes for low and medium pressure boilers of various structures, superheated steam tubes, large smoke tubes, small smoke tubes and arch brick tubes for locomotive boilers. It is mainly used for pipelines conveying low and medium pressure fluids in industrial boilers and domestic boilers. The representative materials are 10 and 20 steel.
Relevant regulations
(1) GB / t5310-2008 seamless steel tubes for high pressure boilers. The chemical composition test method shall be in accordance with relevant parts in gb222-84, methods for chemical analysis of iron, steel and alloy and gb223 methods for chemical analysis of iron, steel and alloy. (2) The chemical composition of imported boiler steel pipes shall be inspected according to the relevant standards specified in the contract.