GB 5310 20G Seamless steel tubes and pipes for high pressure boiler
20G (high quality carbon structural steel pipe) supplied according to GB5310 is used as heating surface pipe fittings, and the maximum wall temperature for long-term use is ≤ 450 ° C. when GB5310 20G seamless steel pipe is used as header and steam pipe, the long-term use temperature shall be ≤ 425 ° C. 

Manufacture:Seamless process ,Hot-finished or Cold-finished
Wall thickness(WT): 2.8 mm——150 mm.
Outer diameter (OD): 23 mm——1500 mm
Length: 6M or specified length as required.
Ends: Plain End, Beveled End, Threaded

Manufacturing methods
(1)Steel smelting method
GB 5310 20G steel will be smelted by electric furnace plus furnace refining, oxygen converter plus furnace refining or electroslag remelting method.
(2)Manufacturing methods and requirements for tube blanks
The tube blank can be produced by continuous casting, die casting or hot rolling (forging).
(3)Manufacturing method of steel tube
GB 5310 20G Steel tubes shall be manufactured by hot rolling (extrusion, expansion) or cold drawing (rolling).

Classification, code
a) Hot rolled steel pipe, codenamed WH;
b) Cold drawn steel pipe, codenamed WC.

Delivery status
The steel tubes shall be delivered in a heat treated condition.

Heat treatment for GB 5310 20G High Pressure Boiler Tubes

According to the production practice,
1)For 20g boiler tube with wall thickness less than 14mm, the normalizing process can be replaced by controlling the finishing rolling temperature ≥ 900 ℃.
2)For 20g boiler tube with wall thickness greater than 14mm, the normalizing process at 910 ℃± 10 ℃ should be carried out in the tube processing plant.(when the wall thickness of 20g high-pressure boiler pipe ≤ 14mm is controlled by the finishing rolling temperature and the performance of the steel pipe is not good, the pipe processing shall also be carried out for the normalizing treatment of 910 ℃± 10 ℃).

Chemical composition of GB 5310 20G

Mechanical properties of GB 5310 20G

Allowable deviation of outer diameter and wall thickness

Testings
(1)Hydraulic test
The steel pipe shall be hydraulically tested one by one, and the eddy current testing can instead of the hydraulic test.
(2)Flattening test
Steel pipes with an outer diameter greater than 22 mm to 400 mm and a wall thickness not greater than 40 mm shall be subjected to a flattening test.
(3)Bending test
Steel pipes with an outer diameter greater than 400 mm or a wall
(4)Flaring test
The steel pipe with an outer diameter of not more than 76 mm and a wall thickness of not more than 8 mm can be used for the flare test.
(5)Low-power test
Steel pipes should be tested at low magnification. Visually visible white spots, inclusions, subcutaneous bubbles, tumbling and delamination are not allowed on the cross-section acid immersion test piece.
(6) Non-metallic inclusions
Steel pipes shall be tested for non-metallic inclusions.
(7)grain size
The finished steel pipe should be tested for grain size.
(8)Microstructure
The finished GB 5310 20G steel pipe of high-quality carbon structural steel shall be ferrite plus pearlite, and no superheated structure shall be allowed;
(9)Decarburization layer
Cold drawn (rolled) finished steel pipes with an outer diameter of not more than 76 mm shall be inspected for the total decarburization layer.
(10)Non-destructive testing
The steel pipe shall be ultrasonically inspected and tested in accordance with the provisions of GB/T 5777.

Surface quality
The inner and outer surfaces of steel pipes do not have cracks, folds, crusting, rolling and separation. These defects shall be completely removed and the depth of defect removal shall not exceed 10% of the wall thickness. The actual outer diameter and wall thickness of the defect removal shall not be less than the minimum allowable for the outer diameter and wall thickness.

End shape
The end faces of the steel pipe should be perpendicular to the axis of the steel pipe, and the incision burrs swill be removed.

 Packaging, marking and quality instructions
The packaging, marking and quality specifications of steel pipes shall comply with the provisions of GB/T 2102. 

Ordering content
Contracts or orders for ordering steel pipes include the following:
a) standard number:GB 5310;
b) product name:Seamless steel tubes;
c) Grade :20Gl;
d) the quantity ordered (total weight or total length);
e) Dimensions (outer diameter × specified minimum wall thickness or outer diameter × average wall thickness in millimeters);
f) Special requirements.

Welding material for 20G seamless steel pipe

Extended reading:

GB 5310 20MnG Seamless steel tubes and pipes for high pressure boiler

Manufacture:Seamless process ,Hot-finished or Cold-finished
Wall thickness(WT): 2.8 mm——150 mm.
Outer diameter (OD): 23 mm——1500 mm
Length: 6M or specified length as required.
Ends: Plain End, Beveled End, Threaded

Manufacturing methods
(1)Steel smelting method
GB 5310 20MnG steel will be smelted by electric furnace plus furnace refining, oxygen converter plus furnace refining or electroslag remelting method.
(2)Manufacturing methods and requirements for tube blanks
The tube blank can be produced by continuous casting, die casting or hot rolling (forging).
(3)Manufacturing method of steel tube
GB 5310 20MnG Steel tubes shall be manufactured by hot rolling (extrusion, expansion) or cold drawing (rolling).

Classification, code
a) Hot rolled steel pipe, codenamed WH;
b) Cold drawn steel pipe, codenamed WC.

Delivery status
The steel tubes shall be delivered in a heat treated condition.

Heat treatment for GB 5310 20MnG High Pressure Boiler Tubes

Chemical composition of GB 5310 20MnG

Mechanical properties of GB 5310 20MnG

Allowable deviation of outer diameter and wall thickness

Testings
(1)Hydraulic test
The steel pipe shall be hydraulically tested one by one, and the eddy current testing can instead of the hydraulic test.
(2)Flattening test
Steel pipes with an outer diameter greater than 22 mm to 400 mm and a wall thickness not greater than 40 mm shall be subjected to a flattening test.
(3)Bending test
Steel pipes with an outer diameter greater than 400 mm or a wall
(4)Flaring test
The steel pipe with an outer diameter of not more than 76 mm and a wall thickness of not more than 8 mm can be used for the flare test.
(5)Low-power test
Steel pipes should be tested at low magnification. Visually visible white spots, inclusions, subcutaneous bubbles, tumbling and delamination are not allowed on the cross-section acid immersion test piece.
(6) Non-metallic inclusions
Steel pipes shall be tested for non-metallic inclusions.
(7)grain size
The finished steel pipe should be tested for grain size.
(8)Microstructure
The finished GB 5310 20MnG steel pipe of high-quality carbon structural steel shall be ferrite plus pearlite, and no superheated structure shall be allowed;
(9)Decarburization layer
Cold drawn (rolled) finished steel pipes with an outer diameter of not more than 76 mm shall be inspected for the total decarburization layer.
(10)Non-destructive testing
The steel pipe shall be ultrasonically inspected and tested in accordance with the provisions of GB/T 5777.

Surface quality
The inner and outer surfaces of steel pipes do not have cracks, folds, crusting, rolling and separation. These defects shall be completely removed and the depth of defect removal shall not exceed 10% of the wall thickness. The actual outer diameter and wall thickness of the defect removal shall not be less than the minimum allowable for the outer diameter and wall thickness.

End shape
The end faces of the steel pipe should be perpendicular to the axis of the steel pipe, and the incision burrs swill be removed.

Packaging, marking and quality instructions
The packaging, marking and quality specifications of steel pipes shall comply with the provisions of GB/T 2102.

GB 5310 15MoG Seamless steel tubes and pipes for high pressure boiler

Manufacture:Seamless process ,Hot-finished or Cold-finished
Wall thickness(WT): 2.8 mm——150 mm.
Outer diameter (OD): 23 mm——1500 mm
Length: 6M or specified length as required.
Ends: Plain End, Beveled End, Threaded

Manufacturing methods
(1)Steel smelting method
GB 5310 15MoG steel will be smelted by electric furnace plus furnace refining, oxygen converter plus furnace refining or electroslag remelting method.
(2)Manufacturing methods and requirements for tube blanks
The tube blank can be produced by continuous casting, die casting or hot rolling (forging).
(3)Manufacturing method of steel tube
GB 5310 15MoG Steel tubes shall be manufactured by hot rolling (extrusion, expansion) or cold drawing (rolling).

Classification, code
a) Hot rolled steel pipe, codenamed WH;
b) Cold drawn steel pipe, codenamed WC.

Delivery status
The steel tubes shall be delivered in a heat treated condition.

Heat treatment for GB 5310 15MoG High Pressure Boiler Tubes

Chemical composition of GB 5310 15MoG

Mechanical properties of GB 5310 15MoG

Allowable deviation of outer diameter and wall thickness

Testings
(1)Hydraulic test
The steel pipe shall be hydraulically tested one by one, and the eddy current testing can instead of the hydraulic test.
(2)Flattening test
Steel pipes with an outer diameter greater than 22 mm to 400 mm and a wall thickness not greater than 40 mm shall be subjected to a flattening test.
(3)Bending test
Steel pipes with an outer diameter greater than 400 mm or a wall
(4)Flaring test
The steel pipe with an outer diameter of not more than 76 mm and a wall thickness of not more than 8 mm can be used for the flare test.
(5)Low-power test
Steel pipes should be tested at low magnification. Visually visible white spots, inclusions, subcutaneous bubbles, tumbling and delamination are not allowed on the cross-section acid immersion test piece.
(6) Non-metallic inclusions
Steel pipes shall be tested for non-metallic inclusions.
(7)grain size
The finished steel pipe should be tested for grain size.
(8)Microstructure
The finished steel pipe with the grades 15MoG will be ferrite plus pearlite, allowing the presence of granular bainite, and no phase change critical temperature between AC1 and AC3 is allowed. (9)Decarburization layer
Cold drawn (rolled) finished steel pipes with an outer diameter of not more than 76 mm shall be inspected for the total decarburization layer.
(10)Non-destructive testing
The steel pipe shall be ultrasonically inspected and tested in accordance with the provisions of GB/T 5777.

Surface quality
The inner and outer surfaces of steel pipes do not have cracks, folds, crusting, rolling and separation. These defects shall be completely removed and the depth of defect removal shall not exceed 10% of the wall thickness. The actual outer diameter and wall thickness of the defect removal shall not be less than the minimum allowable for the outer diameter and wall thickness.

End shape
The end faces of the steel pipe should be perpendicular to the axis of the steel pipe, and the incision burrs swill be removed.

Packaging, marking and quality instructions
The packaging, marking and quality specifications of steel pipes shall comply with the provisions of GB/T 2102.

12Cr1MoVG is a Cr-Mo-V low alloy heat-resistant steel introduced from the Soviet Union in the 1950s and 1960s. Vanadium is an element that reduces the y-phase region. When dissolved in y-fe, it will inhibit the transformation of ADI to pearlite, which is beneficial to the formation of ADI. The total amount of alloy in 12Cr1MoVG steel is only one half of that of 2.25Cr-1Mo steel, but the endurance strength (580 ° C) is 1.4 times of that of 2.25Cr-1Mo steel. Similar steel grades widely used abroad include ASTM a405 p24 in the United States, bs3604 in the United Kingdom, DIN 13crmov42 in Germany, etc.

Manufacture:Seamless process ,Hot-finished or Cold-finished
Wall thickness(WT): 2.8 mm——150 mm.
Outer diameter (OD): 23 mm——1500 mm
Length: 6M or specified length as required.
Ends: Plain End, Beveled End, Threaded

Manufacturing methods
(1)Steel smelting method
GB 5310 12Cr1MoVG steel will be smelted by electric furnace plus furnace refining, oxygen converter plus furnace refining or electroslag remelting method.
(2)Manufacturing methods and requirements for tube blanks
The tube blank can be produced by continuous casting, die casting or hot rolling (forging).
Forging and rolling: the initial forging temperature is 1180-1145 ℃, and the final forging temperature is greater than 850 ℃. After forging, stack cooling is required.

(3)Manufacturing method of steel tube
GB 5310 12Cr1MoVG Steel tubes shall be manufactured by hot rolling (extrusion, expansion) or cold drawing (rolling).

Classification, code
a) Hot rolled steel pipe, codenamed WH;
b) Cold drawn steel pipe, codenamed WC.
 
Delivery status
The steel tubes shall be delivered in a heat treated condition.

Heat treatment for GB 5310 12Cr1MoVG High Pressure Boiler Tubes
 

Chemical composition of GB 5310 12Cr1MoVG

 
Mechanical properties of GB 5310 12Cr1MoVG

 
The annual oxidation corrosion rate of 12Cr1MoVG steel in hot air is 0.042-0.050 mm / year at 580 ° C and 0.129-0.220 mm / year at 600 ° C.

Welding Process

Allowable deviation of outer diameter and wall thickness

Testings
(1)Hydraulic test
The steel pipe shall be hydraulically tested one by one, and the eddy current testing can instead of the hydraulic test.
(2)Flattening test
Steel pipes with an outer diameter greater than 22 mm to 400 mm and a wall thickness not greater than 40 mm shall be subjected to a flattening test.
(3)Bending test
Steel pipes with an outer diameter greater than 400 mm or a wall
(4)Flaring test
The steel pipe with an outer diameter of not more than 76 mm and a wall thickness of not more than 8 mm can be used for the flare test.
(5)Low-power test
Steel pipes should be tested at low magnification. Visually visible white spots, inclusions, subcutaneous bubbles, tumbling and delamination are not allowed on the cross-section acid immersion test piece.
(6) Non-metallic inclusions
Steel pipes shall be tested for non-metallic inclusions.
(7)grain size
The finished steel pipe should be tested for grain size.
(8)Microstructure
The finished steel pipe with the grades 15MoG will be ferrite plus pearlite, allowing the presence of granular bainite, and no phase change critical temperature between AC1 and AC3 is allowed.
Complete phase change product (such as yellow bar martensite); the finished steel pipe of grade 12Cr1MoVG allows the presence of sorbite;
(9)Decarburization layer
Cold drawn (rolled) finished steel pipes with an outer diameter of not more than 76 mm shall be inspected for the total decarburization layer.
(10)Non-destructive testing
The steel pipe shall be ultrasonically inspected and tested in accordance with the provisions of GB/T 5777.
 

Surface quality
The inner and outer surfaces of steel pipes do not have cracks, folds, crusting, rolling and separation. These defects shall be completely removed and the depth of defect removal shall not exceed 10% of the wall thickness. The actual outer diameter and wall thickness of the defect removal shall not be less than the minimum allowable for the outer diameter and wall thickness.
 
 
End shape
The end faces of the steel pipe should be perpendicular to the axis of the steel pipe, and the incision burrs swill be removed.
 
Packaging, marking and quality instructions
The packaging, marking and quality specifications of steel pipes shall comply with the provisions of GB/T 2102.

Use guide:

Recommendations for selecting materials for boiler water walls of ultra-supercritical units:
1. The designed outlet temperature of the boiler is ≤570℃, and 12CrMoG, 15CrMoG, 12Cr1MoVG and similar steel pipes can be used as the water-cooled wall steel.
2. The designed outlet temperature of the boiler is less than or equal to 600℃, and 12Cr1MoVG, T23, T24 steel pipes can be used as the water-cooled wall steel.
3. The designed outlet temperature of the boiler is ≤620℃, and T23 and T24 steel pipes can be used as the steel for the water-cooled wall.
 
Shanghai Boiler Factory has introduced Siemens boiler manufacturing technology. The steels for ultra-supercritical boiler water walls currently being manufactured are: SA209-T1, SA213-T12, SA213-T23; Harbin Boiler Factory has introduced boiler manufacturing technology from Japan’s Mitsubishi Company and is currently manufacturing The steel for the water wall of the ultra-supercritical boiler is: 15CrMoG; Dongfang Boiler Factory has introduced the boiler manufacturing technology of Japan Hitachi, and the steel for the water wall of the ultra-supercritical boiler is currently being manufactured: SA213-T12, SA213-T2, SA213-T22; Beijing The steel for the water wall of ultra-supercritical boilers currently being manufactured by Bavi Company is: SA213-T12, 15CrMoG.

Material introduction
Alias: R102, G102, steel 102 or 102
 
12Cr2MoWVTiB steel is a kind of multi-element microalloyed low-alloy bainite heat-resistant steel developed by ourselves from the end of 1960s to the middle of 1970s in China. Due to the proper coordination of various alloy elements, the steel has high heat strength, and its heat strength performance and service temperature are higher than those of the same kind of steel abroad. Therefore, 12Cr2MoWVTiB can be used for boiler superheat tube panel and reheat The manufacture of boiler tube and main steam tube, in which superheater tube and reheater tube are called serpentine tube.
 
Temperature application range: wall temperature ≤ 600 ℃ (620 ℃ can be used when considering oxidation loss in strength calculation)

Manufacture:Seamless process
Specification: 38mm * 5mm, 42mm * 3.5mm, 42mm * 5mm
Length: 6M or specified length as required.

Surface: Tubes will be varnished (Outside only) to prevent rust.
Marking: Standard + Steel Grade + Size + Heat No + Lot No
Package: Bundles (hexagonal),Wooden Boxes,Crates (steel/wooden) or as required

Chemical composition of GB/T 5610 12Cr2MoWVTiB
 

 Mechanical properties of GB/T 5610 12Cr2MoWVTiB
 

Tolerance of outer diameter and wall thickness
 

 
Testings of GB/T 5610 12Cr2MoWVTiB 
(1)Hydraulic test
(2)Flattening test
(3)Bending test
(4)Flaring test
(5)Low-power test
(6) Non-metallic inclusions
(7)grain size
(8)Microstructure
(9)Decarburization layer
(10)Non-destructive testing
 
Process performance of 12Cr2MoWVTiB
(1) Forging:
The start temperature of rolling (forging) of 12Cr2MoWVTiB steel is 1150 ~ 1200ec, and the end temperature is 850 ° C. after rolling (forging), the steel is cooled by stacking.
 
(2) Cold bending
12Cr2MoWVTiB steel is mainly used for small-diameter steel tubes. Generally, the steel pipes need to be cold bent and do not need heat treatment after cold bending.
 
(3) Heat treatment process (according to GB5310-2008 standard)
Normalizing and tempering: normalizing temperature: 1020ec ~ 1060 ° C; holding for 30min; tempering temperature: 760ec ~ 790ec, holding for 3h; normalizing structure is granular bainite, normalizing + high temperature tempering structure is tempered bainite.
 
(4) Selection of welding materials:
The weldability of 12Cr2MoWVTiB steel is good. It can be used for manual arc welding, gas welding, friction welding, TIG welding and plasma welding. R347 welding rod is used for manual arc welding, h08cr2movnb welding wire is used for gas welding, butt joint with 12Cr1MoV steel, h08crmov or h08cr2movnb welding wire is used. Neutral partial oxidation flame is suitable for gas welding. After welding, it shall be normalized at 1000-1030 ℃ and tempered at 760-780 ° C. before manual arc welding with thickness greater than 6mm, it shall be preheated to 250-300ec, and tempered at 760-780 ° C after welding. After butt welding, it should be heated to 780ec, kept warm for 40 minutes, and then cooled to below 400ec
 
Development of 12Cr2MoWVTiB high pressure boiler tube
◆Professor Liu Rongzao put forward the theory of multiple composite strengthening in the 1960s, developed G102 (12Cr2MoWVTiB) in the late 1960s and G106 (10cr5mowvtib) in the 1970s
◆Professor Liu Rongzao’s theory and G102’s success, Professor V.K. Sikka of the United States adores very much, and T91 research and development has been successful.
◆T23 (HCM2S, cc2199-3, 6cr2w2monbvnb) developed in Japan and T24 (cc2514, 6cr2mo1vtinb) developed in Europe are all G102 modifications.
 
In 1982, when Shanghai Boiler Plant and Harbin boiler plant introduced the manufacturing technology of 300MW and 600MW Subcritical controlled circulation boiler from CE company of the United States, CE company of the United States agreed to use 12Cr2MoWVTiB (steel 102) steel pipe instead of TP347H and TP304H steel tubes to manufacture 300MW and 600MW boiler high temperature superheater and reheater. In the superheater, the actual maximum design temperature of 102 steel tube is 580x ℃; in the reheater, the actual maximum design temperature of 102 steel pipe is 599 ℃.
 
According to DL / t715, 12Cr2MoWVTiB steel is mainly used for superheater and reheater pipes with wall temperature not higher than 600 ° C; however, according to DL / T 715-2015, it is mainly used for superheater pipes and reheater pipes with wall temperature not higher than 575 ° C. It can be seen that the upper limit of service temperature in 2015 version is 25 ° C lower than that in 2000 version, which may be due to the serious oxidation problem when the steel is used in the steam side of the heating surface tube.

GB 5310 12Cr2MoG Seamless steel tubes and pipes for high pressure boiler

Manufacture:Seamless process ,Hot-finished or Cold-finished
Wall thickness(WT): 2.8 mm——150 mm.
Outer diameter (OD): 23 mm——1500 mm
Length: 6M or specified length as required.
Ends: Plain End, Beveled End, Threaded

Manufacturing methods
(1)Steel smelting method
GB 5310 12Cr2MoG steel will be smelted by electric furnace plus furnace refining, oxygen converter plus furnace refining or electroslag remelting method.
(2)Manufacturing methods and requirements for tube blanks
The tube blank can be produced by continuous casting, die casting or hot rolling (forging).
(3)Manufacturing method of steel tube
GB 5310 12Cr2MoG Steel tubes shall be manufactured by hot rolling (extrusion, expansion) or cold drawing (rolling).

Classification, code
a) Hot rolled steel pipe, codenamed WH;
b) Cold drawn steel pipe, codenamed WC.

Delivery status
The steel tubes shall be delivered in a heat treated condition.

Heat treatment for GB 5310 12Cr2MoG High Pressure Boiler Tubes

Testings
(1)Hydraulic test
The steel pipe shall be hydraulically tested one by one, and the eddy current testing can instead of the hydraulic test.
(2)Flattening test
Steel pipes with an outer diameter greater than 22 mm to 400 mm and a wall thickness not greater than 40 mm shall be subjected to a flattening test.
(3)Bending test
Steel pipes with an outer diameter greater than 400 mm or a wall
(4)Flaring test
The steel pipe with an outer diameter of not more than 76 mm and a wall thickness of not more than 8 mm can be used for the flare test.
(5)Low-power test
Steel pipes should be tested at low magnification. Visually visible white spots, inclusions, subcutaneous bubbles, tumbling and delamination are not allowed on the cross-section acid immersion test piece.
(6) Non-metallic inclusions
Steel pipes shall be tested for non-metallic inclusions.
(7)grain size
The finished steel pipe should be tested for grain size.
(8)Microstructure
The finished steel pipe with the grades 15MoG will be ferrite plus pearlite, allowing the presence of granular bainite, and no phase change critical temperature between AC1 and AC3 is allowed.
Complete phase change product (such as yellow bar martensite); the finished steel pipe of grade 12Cr1MoVG allows the presence of sorbite;
(9)Decarburization layer
Cold drawn (rolled) finished steel pipes with an outer diameter of not more than 76 mm shall be inspected for the total decarburization layer.
(10)Non-destructive testing
The steel pipe shall be ultrasonically inspected and tested in accordance with the provisions of GB/T 5777.

Surface quality
The inner and outer surfaces of steel pipes do not have cracks, folds, crusting, rolling and separation. These defects shall be completely removed and the depth of defect removal shall not exceed 10% of the wall thickness. The actual outer diameter and wall thickness of the defect removal shall not be less than the minimum allowable for the outer diameter and wall thickness.

End shape
The end faces of the steel pipe should be perpendicular to the axis of the steel pipe, and the incision burrs swill be removed.

Packaging, marking and quality instructions
The packaging, marking and quality specifications of steel pipes shall comply with the provisions of GB/T 2102.

Ordering content
Contracts or orders for ordering steel pipes include the following:
a) standard numbe:GB 5310r;
b) product name:Seamless steel tubes;
c)Grade :12Cr2MoG;
d) the quantity ordered (total weight or total length);
e) Dimensions (outer diameter × specified minimum wall thickness or outer diameter × average wall thickness in millimeters);
f) Special requirements.

15CrMoG is GB 5310-95 steel grade (equivalent to 13CrMo44 of Federal Germany; corresponding to 1Cr-1 / 2Mo and 1 1 / 4cr-1 / 2mo-si steel widely used in various countries in the world). Its chromium content is higher than 12CrMo steel, so it has higher thermal strength at 500-550 ℃. When the temperature is higher than 550 ℃, the thermal strength of 15CrMoG steel is significantly reduced. When it runs at 500-550ec for a long time, it does not produce graphitization, but it will produce carbide spheroidization and redistribution of alloy elements, which all lead to the decrease of the thermal strength of steel. 15CrMoG steel has good relaxation resistance at 450 ℃. Its pipe making and welding process performance is good. 

GB 5310 15CrMoG Seamless steel tubes and pipes for high pressure boiler

Application