High Pressure Boiler Tubes

Boiler Steel Pipe Supplier-GNEE

Since boiler tubes work under high temperature and high pressure conditions for a long time, the material will creep, the plasticity and toughness will decrease, the original structure will change, and corrosion will occur. Steel pipes used as boilers should have: (1) Sufficient lasting strength; (2) Sufficient plastic deformation ability; (3) Minimal aging tendency and thermal brittleness; (4) High resistance to oxidation, coal ash, and natural gas Corrosion, steam and stress corrosion properties at high temperatures; (5) Good organizational stability and good process performance. The steel types of high-pressure boiler tubes include carbon steel and pearlitic, ferritic and austenitic stainless heat-resistant steels. In order to improve the thermal efficiency of thermal power units and reduce fuel consumption, countries around the world are focusing on developing large-capacity, high-parameter (high temperature, high pressure) thermal power units (above 1000MW). The steam pressure increases 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 tubes. For this reason, new steel grades have been developed to meet the needs of high-parameter power station boilers.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

• Use

Heating surface pipes used in low and medium pressure boilers (working pressure is generally not greater than 5.88Mpa, working temperature is below 450℃); used in high pressure boilers (working pressure is generally above 9.8Mpa, working temperature is between 450℃～650℃) ) heating surface pipes, economizers, superheaters, reheaters, petrochemical industry pipes, etc.

According to the classification of composition materials, it can be divided into 20G high-pressure boiler tube, 12Cr1MoVG high-pressure boiler tube, Gangyan 102 high-pressure boiler tube, 15CrMoG high-pressure boiler tube, 5310 high-pressure boiler tube, 3087 low and medium pressure boiler tube, 40Cr high-pressure boiler tube, 1Cr5Mo high-pressure boiler tube , 42CrMo high pressure boiler tube.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

• The production process of high-pressure boiler tubes varies with different steel types. Taking pearlite-type chromium-molybdenum-vanadium steel as an example, the characteristics of the boiler tube production process are:

(1) The tube blank should be peeled, and the peeling amount is usually 5mm;

(2) Because the steel is hard, the tube blank is mostly cut with oxygen or sawed;

(3) Since the thermal conductivity of chromium-molybdenum-vanadium steel is lower than that of carbon steel, the heating speed should be slightly slower, the heating temperature is 1120~1180℃, and the piercing temperature is 1100~1160℃;

(4) This type of steel is in the range of 1000~1100℃ It has good plasticity and low deformation resistance, so the perforation performance is good. The deformation parameters can be selected according to medium carbon steel or alloy steel (such as 30CrMnSiA);

(5) The rolled steel pipe must be normalized and tempered, and the normalizing temperature is 950 ~980℃, the tempering temperature is 730~750℃, and the holding time is 2~3h;

(6) The size tolerance of the steel pipe is tight to ensure butt welding; the length of the pipe is as long as possible to reduce the number of welding joints.