Low, Medium and High Pressure Boiler Pipe

What is a high pressure boiler pipe?

The high pressure boiler pipe is a kind of boiler pipe and belongs to the seamless steel pipe, which is mainly used for manufacturing the superheater tube, the reheater tube, the gas-guide tube and the main steam pipe for high pressure and superhigh pressure boilers. Manufacturing processes of high pressure boiler pipes include fine drawing processes, brighting processes, hot rolling processes, cold drawing processes and hot expanding processes.

1. An overview of the high pressure boiler pipe
(1) Manufacturing methods
High pressure boiler pipes have the same manufacturing methods as seamless pipes, but they have strict grade requirements of steel which steel pipes are made of. High pressure boiler pipes are divided into general boiler pipes and high pressure boiler pipes two categories based on high or low operating temperature.
① Operating temperatures of general boiler pipes are below 450℃.  Chinese general boiler pipes are mainly made of NO.10 and NO. 20 carbon structural steel by hot roll processes or cold drawn processes. 
② High pressure boiler pipes are often under high temperature and high pressure conditions when they are in operation, which will oxidize and corrode under the actions of high temperature flue gases and water vapors. Therefore, high pressure boiler pipes are required to have high creep rupture strength, good anti-oxidation corrosion resistance and good structure stability.
2. Applications of boiler pipes
① The general boiler pipes are mainly used as superheated steam pipes, large & small smoke pipes and arch tubes which are used for water-cooling wall pipes, boiling-water pipes, superheated steam pipes and locomotive boilers.
② High pressure boiler pipes are mainly used as superheater tubes, reheater tubes, gas-guide tubes and main steam pipes for high pressure and superhigh pressure boilers.
3. Categories
Boiler pipes can be classified into general boiler pipes and high pressure boiler pipes according to high temperatures that they can bear. Both general boiler pipes and high pressure boiler pipes can be divided into various kinds of steel pipes based on their different applications.
4. Rust removal of high pressure boiler steel pipes

Basic methods of high pressure boiler steel pipes’ rust removal are cleaning methods, toolrust removal methods, pickling and abrasive blasting methods. With the development of China’s economy, long-distance oil and gas pipelines are important ways for energy security. In the anti-corrosion work process of oil or gas pipelines, rest removal of high pressure boiler steel pipes’ surfaces can also become factors that influence high pressure boiler steel pipes’ service lives. We can greatly improve technological levels and reduce production costs for the same equipment after ensuring quality of anticorrosive coatings.

What is a low and medium pressure boiler pipe?

Low and medium pressure boiler pipe uses steel ingot or solid tube to perforated capillary, and then dial made by the hot-rolled, cold rolled or cold.

According to incomplete statistics, China’s seamless pipe production enterprises is about 240 more than a seamless steel pipe unit is about more than 250 sets of production capacity of about 450 million tons. Seen from the caliber <φ76, accounting for 35% <φ159-650, accounting for 25%.

From a variety of general purpose of the 1.9 million tons, accounting for 54%; oil pipe 760,000 tons, accounting for 5.7%; hydraulic prop, precision tube 15 million tons, accounting for 4.3%; stainless steel pipe, tube bearings, automotive tube for a total of 50 000 tons, accounting for 1.4%.

Low and medium pressure boiler pipe executive Standard:

• GB3087-1999 low and medium pressure boiler seamless steel tubes.

Low and medium pressure boiler pipe is used to create a variety of structures with low pressure boiler superheated steam roller pipes and locomotive boiler superheated steam pipe, opium pipe, small pipe and arch brick works of high quality carbon structural steel hot-rolled and cold pull (rolled) seamless tube.

Mainly used in industrial boilers and boiler in conveying low pressure fluid in the pipeline. The representative of material 10, 20 steel.

Medium and High Pressure Boiler Pipe
Most common boiler pipe can be devided into two kinds, one is midium pressure boiler pipe, the other is high pressure boiler pipe. Please kindly note that most of high pressure boiler pipe are made from seamless steel pipe.
Boiler pipe has been widely used at heat exchanger pipe and tubing services, high pressure boiler, petrochemical industry pipes, tube exchanger bundle, economizer, super heater, etc.
Based on different working temperature, the medium or high pressure boiler pipe shall be used. Normally classified as below cases:
The operation temperature of general boiler pipe is lower than 450℃. The medium pressure boiler pipe mainly adopts hot rolling process or cold drawing process.
High pressure boiler pipe are often used in high temperature and high pressure working conditions. Under the action of high temperature flue gas and steam, the pipe will occur oxidation and corrosion. It is required high pressure boiler pipe that has high endurable strength, high oxidation corrosion resistance and good tissue stability.
Difference between Medium and High Pressure Boiler Pipe
Boiler steel pipes includes medium pressure boiler pipe and high pressure boiler pipe, it is often manufactured in seamless procedures, welded steel pipe is not applicable. It has been widely used at heat exchanger pipe and tubing services, tube exchanger bundle, high pressure boiler, economizer, super heater, petrochemical industry pipes, etc.
Based on different working temperature, the medium or high pressure boiler pipe shall be used. Normally classified as below cases:
1. The operation temperature of general boiler pipe is lower than 450℃. The medium pressure boiler pipeline mainly adopts hot rolling process or cold drawing process.
2. High pressure boiler pipes are often used in high temperature and high pressure conditions. Under the action of high temperature flue gas and steam, the pipe will occur oxidation and corrosion. It is required high pressure boiler pipe that has high durable strength, high oxidation corrosion resistance and good tissue stability.

ASTM A179 Heat Exchanger Tubes

ASTM A179/A179M, ASME SA179/SA179M is the standard applicable to Seamless cold drawn low carbon steel heat exchanger and condenser tubes.

When we place a specific order for SA 179 tubing, we should include below material specifications:

• Standard and the name of material: ASTM A179 / ASME SA 179 seamless tubes.
• Manufacturing types in cold drawn
• Quantity in meters, feet, or pieces.
• Size including Diameters and minimum wall thickness
• Length per pieces (Random or fixed length shall be specified)
• Chemical composition (optional)

ASTM A179 (ASME SA179) pipes and its usage

ASTM A179 seamless tubes are widely used in industries such as petroleum, chemical, medical, food, light industry, machinery, instrument, include industrial pipeline and mechanical structure parts, etc.

What is a heat exchanger used for?
A heat exchanger is a device designed to efficiently transfer or “exchange” heat from one matter to another. When a fluid is used to transfer heat, the fluid could be a liquid, such as water or oil, or could be moving air. The most well known type of heat exchanger is a car radiator.

ASTM A179 / A179M – 90a(2012) Standard Specification for Seamless Cold-Drawn Low-Carbon Steel Heat-Exchanger and Condenser Tubes

There are probably hundreds of different methods for packing a abrasion resistant pipe and Elbows, and most of them have merit, but there are two principles that are vital for any method to work prevent rusting and Sea transportation security.

Because of ASTM A179 grade’s temperature withstanding capabilities, it is applied to steel pipe of tubular heat exchanger, condensers and similar heat transfer equipment. Our ASTM A179 seamless tubes are used in sugar mills & distilleries, pumps and petrochemicals, cement and construction industries and steel plants. ASTM A179 steel tube from stock or from reputed steel mills. We also offer steel fabrication service where steel plates can go through processings like cutting, welding, bending, machining, pre-coating, pre-lined, beveling, or as you require.ASTM A179 Tubes shall be made by the seamless process and shall be cold drawn. Heat and product analysis shall be performed wherein steel materials shall conform to required chemical compositions of carbon, manganese, phosphorus, and sulfur. The steel materials shall also undergo hardness test, flattening test, flaring test, flange test, and hydrostatic test.

This specification covers minimum-wall thickness, seamless cold-drawn low-carbon steel tubes for tubular heat exchangers, condensers, and similar heat transfer apparatus. Tubes shall be made by the seamless process and shall be cold drawn. Heat and product analysis shall be performed wherein steel materials shall conform to required chemical compositions of carbon, manganese, phosphorus, and sulfur. The steel materials shall also undergo hardness test, flattening test, flaring test, flange test, and hydrostatic test.

Note:

• Mill test certificates will be issued according to EN10204.3
• All tubes shall be supplied as per applicable ASTM Specification.
• The tubes Shall be Seamless and the testing shall be as per A 450 / A450M.

ASTM A192 / A192M Standard Specification for Seamless Carbon Steel Boiler Tubes for High-Pressure Service

The ASTM A192 belongs to the carbon seamless tubes, which is specially designed for high, middle, low pressure purpose in seamless carbon steel boiler tubes and as super heater tubes.

Description:

This specification has been approved for use by agencies of the Department of Defense.

Consult the DoD Index of Specifications and Standards for specific year of issue which has been adopted by the Department of Defense.

Size (mm): O.D.:6.0-114.0 W.T.:1-15 L:max 12000

Delivery Condition : As different requirements,It including pickling,etc.

Test:

1.Hydrostatic or Nondestructive Electric Test2.Heat Treatment:Min temperature 650.3.Surface Condition:Free of scale,A slight amount of oxidation will not be considered as scale.4.Flattening Test,Flaring Test.Flange Test,Hardness Test,Hydrostatic Test

Features Specifications

Scope:

1. This specification covers minimum-wall-thickness, seamless carbon steel boiler tubes and superheater tubes for high-pressure service. 
2. The tubing sizes and thicknesses usually furnished to this specification are 1/2 in. to 7 in. [12.7 to 177.8 mm] outside diameter and 0.085 to 1.00 in. [2.2 to 25.4 mm], inclusive, in minimum wall thickness. Tubing having other dimensions may be furnished, provided such tubes comply with all other requirements of this specification.
3. Mechanical property requirements do not apply to tubing smaller than 1/8 in [3.2 mm] inside dimeter or 0.015 in. [0.4 mm] thickness.
4 When these products are to be used in applications conforming to ISO Recommendations for Boiler Construction, the requirements of specification A 520 shall supplement and supersede the requirements of this specification.
5. The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the specification. The inch-pound units shall apply unless the “M” designation of this specification is specified in the order.

20G seamless steel pipe for boiler

20G seamless steel pipe is a high-quality carbon structural steel, boiler material, the carbon content of 0.17-0.24%, tensile strength of 410Mpa, yield point 230-250Mpa.

Is our main production of steel, we can provide 20G Seamless pipe with high quality and competitive price. Here to introduce you to our 20G seamless pipe basic chemical properties and mechanical properties.

20G is the steel material of GB 5310- 2008. GB 5310- 2008 standard is applicable to seamless tubes for making steam boiler whose pressure is high or higher and seamless tubes used as pipelines.

Chemical Compositions(%) of 20G:

Chemical elements	Data
Carbon	0.17-0.24
Silicon	0.17-0.37
Manganese	0.70-1.00
Phosphorus(max)	0.03
Sulfur(max)	0.03
Chromium(max)	0.25
Molybdenum(max)	0.15
Cuprum(max)	0.2
Nickel(max)	0.25
Vanadium(max)	0.08

Mechanical Properties of 20G：

Properties	Data
Yield Strength (Mpa)	≥415
Tensile Strength (Mpa)	240
Elongation (%)	22

The W.T. tolerance of 20G：

W.T.(S)		Tolerance of W.T.
<3.5		+15%(+0.48mm min)
		-10%(+0.32mm min)
3.5-20		+15%,-10%
>20	D<219	±10%
	D≥219	+12.5%,-10%

GB5310 20G boiler steel pipe Other Name

GB5310 20G boiler steel pipe, 20G boiler steel pipe, 20G boiler pipe.

Characteristics of boiler pipe

Small diameter high-pressure boiler tube surface defects that affect the quality, mainly due to waste generation.
Boiler pipes often in high temperature and high pressure work, pipe smoke and water at high temperature steam oxidation and corrosion effects will occur, thus requiring durable steel with high strength, high oxidation resistance, and good organizational stability, high pressure boiler tube in addition to chemical composition and mechanical properties, hydrostatic testing done by the root, to be flaring, flattening test. Steel to heat treatment delivery. In addition, the finished steel microstructure, grain size, there are certain requirements decarburization.
High-pressure boiler tubes are seamless steel pipe categories. Seamless same manufacturing method, but used in the manufacture of steel pipe, there are strict requirements. Often in high-pressure boiler tubes at high temperature and pressure conditions of use, the tube under the effect of high temperature gas and water vapor, oxidation and corrosion will occur. Require durable steel with high strength, high resistance to oxidation corrosion, and have good organizational stability.
High-pressure boiler tube is mainly used to manufacture high-pressure and high pressure boiler superheater tubes, reheater tubes, windpipe, the main steam pipe. High-pressure boiler tubes for low and medium pressure boiler (working pressure is generally not more than 5.88Mpa, working temperature below 450 ℃) of heating surface tubes; used for high-pressure boilers (above 9.8Mpa working pressure in general, the working temperature of 450 ℃ ~ 650 ℃ between) the heating surface tubes, economizer, superheater, reheater, petrochemical industrial pipe.

Hardness testing methods of high-pressure boiler tubes

High pressure boiler tube hardness testing should take into account its mechanical properties, which is related to stainless steel as raw material for the deformation, such as punching, cutting processing performance and quality.

Therefore, all of the high-pressure boiler tubes need to conduct mechanical tests. Mechanical performance testing method is mainly divided into two kinds, one kind is tensile test, the other kind is usually hardness test.

Tensile test is the high pressure boiler tube sample, high pressure boiler tube tend to sample to the fracture on tensile testing machine, mechanical properties and determination of one or more, usually only determination of tensile strength, yield strength, break elongation, and reduction of area. Tensile test is the most basic mechanical properties of metallic materials testing methods, almost all of the metal material, as long as the requirements of the mechanical properties of the high pressure boiler tube, the provisions of the tensile test. Especially those appearance and high pressure boiler tube is not good for the material of hardness test, tensile test became the only means of mechanical properties testing.

Application: For high, middle, low pressure boiler and pressure purpose

Production Standard, Grade, Steel No:

• ASTM A178 Grade A, C, D
• ASTM A192
• ASTM A210 GradeA-1, C
• BS3059-Ⅰ 320 CFS
• BS3059-Ⅱ 360, 440, 243, 620-460, 622-490, S1, S2, TC1, TC2
• EN10216-1 P195TR1/TR2, P235TR1/TR2, P265TR1/TR2
• EN10216-2 P195GH, P235GH, P265GH, TC1, TC2
• DIN17175 ST35.8, ST45.8
• DIN1629 ST37.0, ST44.0, ST50.0
• JIS G3454 STPG370, STPG410
• JIS G3461 STB340, STB410, STB440
• GB5310 20G, 15MoG, 12CrMoG, 12Cr2MoG, 15CrMoG, 12Cr1MoVG, 

Delivery Condition: Annealed, Normalized, Normalized and Tempered
Inspection and Test: Chemical Composition Inspection, Mechanical Properties Test(Tensile Strength,Yield Strength, Elongation, Flaring, Flattening, Bending, Hardness, Impact Test), Surface and Dimension Test,No-destructive Test, Hydrostatic Test.
Surface treatment: Oil-dip, Varnish, Passivation, Phosphating, Shot Blasting

Boiler tubing is used in these industries:

• Steam Boilers
• Power Generation
• Fossil Fuel Plants
• Electric Power Plants
• Industrial Processing Plants
• Cogeneration Facilities

What is boiler pickling

Boiler pipe often accumulate oxide or other contaminants in the process of manufacturing, transportation and installation, boiler heating surface corrosion damage in the initial running.

The the boiler has safely operated for a period of time, in the high heat load area (such as a burner zone) occurs oxide deposition of the pipe wall, resulting in over-temperature of the heating surface or tube rupture.

Natural water is an aqueous solution of electrolyte contact with the metal can easily generate electrochemical corrosion, salt scale deposition in the steam valve failure and valve leak may cause the valve action. , Boiler installed and ready to run in respect of a series of measures to ensure the cleaning of the heating surfaces.

Boiler pickling operations beginning, Condenser — feedwater system should be kept filled with demineralized water. And chemical cleaning pump equipment at full capacity flow corresponding to the establishment of recycling, including low-pressure heaters, deaerator, as well as high-pressure heaters, feed pumps should bypass. After the pickling cycle, and the fluid within the system reaches 200F, glycolic acid, formic acid and ammonium chloride inhibitors mixed solution was injected into the system. To ensure the uniformity of the concentration, the acid solution should be injected at a constant rate, i.e. the injection time equal to one complete cycle through the system needs time. Pickling is complete, it can be used in addition to the saline-filled system to discharge waste pickling solution and flush the system. Of condensate should pickling after filling containing 40ppm ammonia and 500ppm hydrazine to inactivate the system. Passivation during the operation, the pH value should be maintained at 9. O or greater, hydrazine concentration above 200ppm. Note that if some of the parts made of stainless steel of the feedwater heater, can not spend France formulated solution pickling.

With caustic period, there may have been suspended solids abrasion damage to the acid solution, or wash pumps and other equipment should be bypassed or remove the inner member. Valves and pipes should be checked to prevent acid accidental discharge, or equipment of accidental contamination. Should continue to cycle in the pickling solution, the first time after the return from the high-pressure heater 4-6 hours, once every half an hour in water samples sampling and analysis of the iron content. Feedwater heater bypass cleaning should change the fluid flow paths in the pickling period.

Heat defect of high-pressure boiler tube

High-pressure boiler tubes are frequently occurs fault because of high temperatures, affecting the entire heating system, mainly due to an internal boiler for heat treatment is not perfect, a lot of heat can not be effectively converted and timely treatment.

Burnt phenomenon

Generally refers to the high-pressure boiler tube heating is too high, causing not only lead to coarse grains, and grain boundary melting or partial oxidation occurs, leading to the weakening of the grain boundary, known as the over-burning. After the serious deterioration of steel over-burning performance, the formation of cracks during quenching. In the event of over-burning phenomenon, the occurrence of structural components can not be burned into them again, only to eliminate, not only is the device to introduce economic waste, but also affect the stability of the entire heating system. For this reason, in the course, we must take preventive measures, preventive measures to reduce the probability of burning had occurred.

Overheating

Overheating than over-burning phenomenon, its harm is relatively low, there have been burning phenomenon of structural components must be eliminated, and structural components overheating cooling treatment can be achieved by taking measures to continue the operation of components. 

Decarbonization and oxidation

Just upon heating, the surface layer of the medium of oxygen and carbon, hydrogen, carbon dioxide and water vapor react, after reducing the surface carbon concentration is called decarburization off steel quench surface hardness, fatigue strength and abrasion resistance is lowered, and surface residual tensile stress is easy to form a mesh surface cracks. Upon heating, the alloying elements iron and steel surfaces and medium oxygen, carbon dioxide, water vapor and other phenomena occurring oxide film produced by the reaction is called oxidation. After the high temperature oxidation of the workpiece dimensional accuracy and surface brightness deterioration of the oxide film has poor hardenability steel prone to hardening soft spots.

Hydrogen embrittlement

Ductility and toughness decrease when heated at the scene in the hydrogen rich gas called hydrogen embrittlement of high strength steels. Workpiece appear in addition to hydrogen embrittlement by hydrogen embrittlement treatment can eliminate, the use of vacuum or inert gas atmosphere with low hydrogen heating can avoid hydrogen embrittlement.

How to choose high quality boiler tubes?

What to Consider Before You Buy
Climate
If you live you in a cold climate, a boiler may be a good choice for your home. But if you live in a warm climate, you may not need a central heating system. In that case, consider a heat pump, which can satisfy your air conditioning needs as well as moderate heating requirements.
Fuel Type
Gas-fueled boilers may cost less to operate than oil-fueled ones if heating oil prices are high. However, the fuel type you choose will depend on what’s available in your area.
Sizing
The boiler’s size is as important as its efficiency. If the boiler is undersized, it won’t work efficiently; if it is oversized, it will cost you more to heat your home. Work with a heating and cooling professional, who should use an Air Conditioning Contractors of America (ACCA) Manual J calculation to determine the right boiler type and size. The calculation will take into consideration your home’s foundation, wall thicknesses, insulation values, windows, air filtration and more.
Cooling
Boilers only provide heat; so you’ll need a cooling system, too, if you want to air condition your home.
Energy Efficiency
Boilers are rated with an annual fuel-utilization-efficiency (AFUE) score, which tells you how much energy is being converted into useable heat. New boilers must have an AFUE rating of at last 80 percent, and high-efficiency models are 90 to 98.5 percent efficient. The higher the rating, the higher the equipment cost, but the lower the operating cost.
For example, say your current boiler’s AFUE score is 65 percent and you pay $1,300 a year for fuel bills. If you install a high-efficiency natural gas system with an AFUE of 90 percent, your total yearly savings should be about $364.
The possible quality problems of the boiler tube
Boiler tube quality problems mainly in the cracks, shrinkage, peeling, pit, layered, pinhole, slag and so on. Boiler tube defects and injuries that may exist in the same smelting and rolling process.
The main defects in the surface of the boiler tube and an outer surface than the inner surface.
About 70 percent of these defects from the raw material (billets), billets in blowing insufficient residual slag material, shrinkage, etc., with which there may be rolled steel transverse cracks, laminated, folded, heavy leather and other defects, longitudinal cracks caused mostly rolling strain. If the boiler tube in the emergence of these defects or injuries, considers the material appeared discontinuous density within the material is damaged, it is possible leaks in the hydraulic pressure test, boiler pressure element is made at run time there may leak or burst pipes. Because of this, in order to ensure the quality of boiler pipe, whether it is related to a foreign country or boiler seamless steel pipe standards are clearly defined, as the process performance guarantee, steel hydraulic test should be made by the root.
The purpose of the hydrostatic test, there are two: one is the process of hydraulic test, its purpose is to test the material (or components) for leaks, that the sealing properties of materials; the other is the verification of the hydrostatic test, its purpose is to strength test material (or components) is adequate. From here, the hydrostatic test pressure boiler tube is part of the process of trial, is the material density test, if the test material is dense and continuous; it is not the strength of experimental verification.
Strength theory of mechanics of materials known from, seamless steel components are thin and long, and its diameter is very small, even for thin-walled tubules can withstand a lot of pressure.

Source: China Boiler Pipe Manufacturer – Yaang Pipe Industry Co., Limited (www.steeljrv.com)

(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)

If you want to have more information about the article or you want to share your opinion with us, contact us at [email protected]

Please notice that you might be interested in the other technical articles we’ve published:

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  • How to get high quality steel pipes

  • Manufacturing process of cold rolled steel pipe

  • How to get high quality boiler tubes

  • How to get high quality flanges

  • How to get high quality alloy steel pipes

  • How to get high quality pipe fittings

  • How to get high quality heat exchanger tubes

  • The difference between steel tubes and steel pipes

  • THE DIFFERENCE BETWEEN STEEL TUBES AND STEEL PIPES

  • Difference between welded steel pipe and seamless steel pipe

  • Characteristics of seamless steel pipes

Reference:

• https://www.yaang.com