The material and steel grade of high-pressure boiler tubes have strict requirements. They are designed to work under high temperature and high pressure conditions. A large amount of water vapor will be produced in the high temperature working environment, which can cause corrosion of the steel pipes. That require the steel used in high-pressure boiler tubes to have good corrosion resistance and structural stability.
High-pressure boiler tubes are used to make superheater tubes, reheater tubes, air ducts, and main steam pipes for high-pressure and ultra-high-pressure boilers. The low and medium pressure boiler tubes are executed according to national standard 3087, while the high-pressure boiler tubes are executed according to national standard 5310. The outer diameter of the hot-rolled tubes for high-pressure boiler tubes usually ranges from 22mm to 530mm, with varying wall thicknesses of 20mm to 70mm. The outer diameter of the cold-drawn tubes ranges from 10mm to 108mm, with varying wall thicknesses of 2mm to 13mm.
The steel grades of carbon structural steel for high-pressure boiler tubes include 20G, 20MnG, and 25MnG. The steel grades of alloy structural steel include 15MoG, 20MoG, 12CrMoG, 15CrMoG, 12Cr2MoG, 12CrMoVG, 12Cr3MoVSiTiB, etc.