One, what is high-pressured boiler canal?

High-pressured boiler is in charge ofIt is the utility boiler that is used technically at making high pressure and above parameter, superheater, reheater, couplet box and advocate the special type steel tube of the equipment such as vapour conduit.

It is in for a long timeHigh temperature, high pressure reachs complex mediummove below extremely abominable operating mode, its quality is mattered to directly whole generate electricity of the systemSafe, efficiency and life. A all be no longer in force is brought about possibly stop disastrously machine even accident.

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2, the extreme work environment of high-pressured boiler canal and core ask

To answer these environments, high-pressured boiler canal must have the following and transcendental property:

1. Abiding high strenth and fight creep function

• Core requirement: In high temperature (normally > 450 ° C) fall with high pressure, the metal can happen slow, persistent plasticity is out of shape, namely " creep " . High-pressured boiler canal must be had extremely tallCombat creep strengthAndLong-term strength, ensure inside design life (it is normally 100 thousand - 300 thousand hours) do not happen rupture or excessive be out of shape.

Exceedingly good high temperature fights oxidisability

• Core requirement: Below environment of high temperature vapour, wall of steel tube inside and outside can be oxidized. Must can form compact oxidation film, prevent oxygen to diffuse upcountry further, make sure tube wall ply is not corroded to decrease continuously thin.

Good constituent stability

• Core requirement: Below long-term high temperature, the microcoic organization of steel (like carbide) can produce change, cause function deterioration (bate or fragile change) . High-pressured boiler canal needs to use the rolled steel that organizes stability in be used for a long time.

Tall corrosion resistance can

• Can resist flue gas, flying ash and steam are corroded.

Outstanding technical properties

• Include goodLeng Wanhe heats up curved function, Weldability can, make in order to facilitate field assembly is mixed.

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3, main material is qualitative with steel class (from low to tall)

The material that high-pressured boiler provides chooses to use temperature with its directly character / pressure link up with, the technology that formed a clarity develops way.

1.Carbon steel

• Represent steel step: 20G(canal of commonly used carbolic steel boiler)

• Scope of application: With Yu Biwen ≤ the heating surface pipe of 450 ℃ (be like water-cooling wall, economizer) and header and vapour conduit.

• Characteristic: The value is relative economy, the material that is the foundation in boiler canal is qualitative.

2.Chromic molybdenum low-alloy steel (use extensive series)

This is high-pressured boiler canalMain force, will increase high temperature intensity and corrosion resistance significantly through joining Cr and Mo.

• 15CrMoG: With Yu Biwen ≤ box of the boiler heating surface of 550 ℃ , couplet is mixed vapour conduit.

• 12Cr1MoVG: Applying extremely extensive, function excel 15CrMoG, with Yu Biwen ≤ the high-pressured conduit of 570 ℃ .

• T/P11, t/P12: The familiar name in ASTM standard, the 15CrMoG level of corresponding home.

• T/P22 (2.25Cr-1Mo): Classical steel is planted, use at high temperature header and vapour conduit.

3.Refractory steel of tall chromic martensite (contemporary exceed critical / super- exceed critical aircrew key material)

This is for pursuit more efficient develops with parameter high end material.

• T/P91 (9Cr-1Mo-V-Nb): The material of milepost type. T/P22 of outclass of intensity of its high temperature, allow to design thinner tube wall, reduce thermal stress. The superheater that is used extensively at exceeding critical unit, reheater and advocate vapour conduit.

• T/P92 (NF616) , t/P911: Optimize further on P91 foundation, performance is stronger, it is to exceed the brunt material that exceeds critical unit.

• T/P122: Contain 12% chromium, fight oxidize and corrode ability stronger.

4.Austenite stainless steel

When temperature exceeds 600 ℃ , ferrite / martensite steel satisfies a requirement hard, need to use austenite stainless steel.

• TP304H, TP321H, TP316H, TP347H: The share with the high temperature in be being used at boiler --The end class of superheater and reheater.

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4, workmanship and strict quality control

High-pressured boiler canal basically is usedSeamless steel tubeCraft production, with ensuring public security truly complete dependability.

Its quality control is all steel tube in strict one of, include:

• Strict chemical composition is controlled: Extremely low to the harmful element such as P, S.

• Overall mechanical performance examines: Include normal temperature drawing, high temperature abiding experiment with creep.

• 100% nondestructive detect: Ultrasonic flaw detection, eddy current flaw detection, ensure without any interior and exterior blemish.

• Rigid geometrical size control: Assure to solder and assemble quality.

• Hydraulic experiment: Test and verify bear control capacity.

• Metallographic organization examines: Ensure microcoic organization accords with a requirement.

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5, basically use position

In an utility boiler, high-pressured boiler canal basically uses in the following and crucial position:

1. Water-cooling wall: Boiler the chamber of a stove or furnace the standpipe all around, absorb radiation heat, heat water saturated vapour. Multi-purpose carbolic steel tube (be like 20G) .

2. Economizer: Use flue gas beyond to heat up warm-up boiler water supply, improve efficiency. Multi-purpose carbolic steel tube (be like 20G) .

3. Superheater: Will saturated vapour heats to have constant temperature and pressureOverheat vapour, this is the key that improves power station efficiency. Differ according to temperature, from low-alloy steel (like 12Cr1MoVG) to tall alloy steel (like T/P91) arrive again austenite stainless steel (like TP347H) have use.

4. Reheater: Heat the vapour of eduction of crock of turbine high pressure again, send a middling pressure crock acting next. Its material qualitative requirement and superheater are similar.

5. Couplet box and join conduit: Assemble and the large wall part that distribute labour to pledge, use the tall chromium steel of high strenth more, be like P91, P92.

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Summary is combed with the relation

Let us will it and before the notional connection that discuss rises:

Feature	High-pressured boiler is in charge of	Common fluid is in charge of (like GB/T 8163)	The structure uses a pipe (like GB/T 8162)
Core requirement	High temperature long-term strength, fight stability of creep, organization	Room temperature / in ability of Wen Cheng pressing and sealing	Room temperature is mechanical intensity, stiffness
Working environment	High temperature, high pressure, vapour is corroded	Normal temperature or medium medium of lukewarm, fluid	Normal temperature, bearing, do not have medium
Material is qualitative	Alloy steel(Cr-Mo-V series is advocate)	Basically beCarbon steel(like 20# )	Carbon steel, low-alloy steel
Quality standard	Strict(high temperature capability, nondestructive detects)	Strict(hydraulic pressure experiment)	Groovy(mechanical function)
Application	Utility boiler, nuclear energy equipment	Factory hydraulic pressure, pneumatic conduit	Building construction, mechanical frame