Common details of high-pressure boiler seamless steel pipes

High-pressure boiler steel pipes are a type of boiler steel pipe and belong to the category of seamless steel pipes. The manufacturing method is the same as that of seamless pipes, but there are strict requirements on the type of steel used to manufacture steel pipes. High-pressure boiler steel pipes are often in high-temperature and high-pressure conditions when used. Under the action of high-temperature flue gas and water vapor, the pipes will oxidize and corrode. The steel pipes are required to have high lasting strength, high anti-oxidation and corrosion performance, and good organizational stability. High-pressure boiler steel pipes are mainly used to manufacture superheater tubes, reheater tubes, gas guide tubes, main steam pipes, etc. for high-pressure and ultra-high-pressure boilers.

Among them, the substitute materials are 20 pot, 15 chromium-molybdenum pot, 12 chromium-1 molybdenum-vanadium pot, 15 nickel-1 manganese-molybdenum-niobium-copper, 10 chromium-9-molybdenum-1-vanadium-niobium-nitrogen, etc.

Due to long-term operation under high-temperature and high-pressure conditions, the boiler steel pipe will creep, plasticity and toughness will decrease, the original organization will change, and corrosion will occur. Steel pipes used for boilers should have the following characteristics:
(1) Sufficient endurance strength;
(2) Sufficient plastic deformation capacity;
(3) Minimum aging tendency and hot brittleness;
(4) High resistance to oxidation, coal ash, corrosion under high temperatures of natural gas, steam, and stress corrosion;
(5) Good structural stability and good process performance.

The steel grades of high-pressure boiler steel pipes include carbon steel and pearlite, ferrite, and austenite stainless heat-resistant steel. To improve the thermal efficiency of thermal power generating units and reduce fuel consumption, countries around the world are focusing on developing large-capacity, high-parameter (high temperature, high pressure) thermal power generating units (above 1000MW). The steam pressure is increased to 31.5~34.3MPa, and the superheated steam temperature reaches 595~650℃, developing towards ultra-high pressure critical pressure, which puts higher requirements on high-pressure boiler steel pipes. For this purpose, new steel grades have been developed to meet the needs of high-parameter power station boilers.