This standard specifies the dimensions, shape, weight, technical requirements, test methods, inspection rules, packaging, marking and quality certificates of seamless steel pipes for high-pressure fertilizer equipment. This standard applies to high-quality carbon steel, low-alloy steel and alloy steel seamless steel pipes for high-pressure fertilizer equipment and pipelines. It is also used for other chemical equipment and other purposes. GB 6479-2000 Seamless Steel Pipes for High-Pressure Fertilizer Equipment GB6479-2000 Standard Download Decompression Password: www.bzxz.net

GB6479—2000
This standard adopts I509329-2:1997 "Seamless Steel Tubes for Pressure Vessels—Technical Delivery Conditions—Part 2: Carbon Steel and Alloy Steel with Specified High Temperature Performance" in a non-equivalent manner
The steel tube size tolerance, curvature, flattening deformation coefficient and other indicators of this standard are stricter than the international standards, and the mechanical performance indicators are equivalent to the international standards.
Compared with the previous version of the standard, this standard has been revised in the following articles. 1. The size tolerance indicators have been modified, the original Table 1 has been cancelled, and the size specifications have been changed to reference Table 1 in GB/T17395-1998. 2. The 12SiMoVNb grade has been added, and the phosphorus and sulfur content in each grade has been modified. 3. The delivery status of the steel tube has been supplemented. 4. The clause of replacing the hydraulic test with leakage magnetic flaw detection has been added, and the clause of replacing the hydraulic test with ultrasonic flaw detection has been cancelled. 5. The requirement of flattening test for steel pipes with outer diameter greater than 400 mm has been cancelled. 6. The requirements of low-power inspection for steel pipes rolled by steel chain and the requirements of non-metallic inclusion inspection for steel pipes rolled by continuous casting and ingot have been added. 7. Specific provisions have been made for the ultrasonic inspection level. This standard replaces GB6479-1986 "High-pressure keyless steel pipes for fertilizer equipment" from the date of implementation. This standard is proposed by the State Metallurgical Industry Bureau. This standard is under the jurisdiction of the National Steel Standardization Technical Committee. The drafting units of this standard are: Anshan Iron and Steel Group Corporation, Chengdu Seamless Steel Pipe Co., Ltd. The main drafters of this standard are: Pu Zhimin, Tong Changbo, Guo Keping, Xu Yongmei, Feng Wenhua. This standard was first issued in June 1986. 819
1 Scope
National Standard of the People's Republic of China
Seamless steel tubes for high-pressurcfor chemical fertilizer equipmentsGB 64792000
neq ISO 9329-2:1997
Generate GB6479-1986
This standard specifies the size, shape, weight, technical requirements, test methods, inspection rules, packaging, marking and quality certificate of seamless steel tubes for high-pressurcfor chemical fertilizer equipment.
This standard applies to high-quality carbon steel, low alloy steel and alloy steel seamless steel tubes for high-pressure fertilizer equipment and pipelines. It is also used for other chemical equipment and other purposes.
2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are all valid. All standards are subject to revision and parties using this standard should investigate the possibility of using the most recent versions of the following standards. GB/T 222-1984 Sampling method for chemical analysis of steel and allowable deviation of chemical composition of finished products GB/T 223.5-1997 Chemical analysis methods for steel and alloys - Prototype silicate molybdate photometric method for determination of acid-soluble silicon content - Chemical analysis methods for steel and alloys - Ammonium persulfate oxidation pan method for determination of chromium content GB/T 223.11-1991
GB/T 223.14-1989
GB/T 223.19-1989
Chemical analysis methods for steel and alloys
Chemical analysis methods for steel and alloys
Chemical analysis methods for steel and alloys
G3/T 223.23-1994
Chemical analysis methods for steel and alloys
GB/T 223.26-1989
GB/T 223. 40—1985
Methods for chemical analysis of steel, iron and alloy
GB/T 223.43-1994Methods for chemical analysis of steel, iron and alloyGB/T 223.58—1987
GB/T 223.59—1987
Methods for chemical analysis of steel, iron and alloy
Methods for chemical analysis of steel, iron and alloy
GB/T 223.68--1997
GB/T 223.69—1997
GB/T 226—1991
GB/T 228—1987
GB/T 229-—1994
GB/T 241—1990
GB/T 242—1997
GB/T246-1997
GB/T 1979—1980
GB/T 2102—1988
GB/T4336--1984
Determination of vanadium content by extraction photometry with nitropropene
Determination of copper content by extraction photometry with chloroform
Determination of nickel content by direct photometry with thiocyanate
Determination of molybdenum content by ion exchange separation-chlorosulfonol S photometry
Determination of tungsten content by titration with sodium nitrite-sodium nitrite
Determination of manganese content by titration with antimony phosphorus and molybdenum blue
Determination of sulfur content by titration with potassium iodate after combustion in a tubular furnace
Determination of carbon content by gas volumetric method after combustion in a tubular furnace Chemical analysis methods for steel and alloys
Macrostructure of steel and defects acid immersion test method Metal tensile test method
Metal Charpy notch impact test method
Metal pipe hydraulic test method
Metal pipe expansion test method
Metal pipe flattening test method
Structural steel macrostructure defect rating chart
Acceptance, packaging, marking and quality certificate of steel pipe Photoelectric emission spectrum analysis method for carbon steel and medium and low alloy steel Approved by the State Administration of Quality and Technical Supervision on October 25, 2000 820
Implementation on September 1, 2001
GB/T5777-1996
GB/T7735—1995
GI3/T 10561—1989
GB/T 12606—1999
GB/T 17395—1998
GI3/T 17505—1998
Y13/T 5137-—1998
3 Dimensions, shape and weight
3.1 Outer diameter and wall thickness
GB 6479—2000
Ultrasonic flaw detection test method for seamless steel pipe
Eddy current flaw detection test method for steel pipe
Microscopic evaluation method for non-metallic inclusions in steelMagnetic leakage flaw detection method for steel pipe
Dimensions, shape, weight and allowable deviation of seamless steel pipeGeneral technical requirements for delivery of steel and steel products
Seamless steel pipe for high pressureRound pipe
3.1.1 The outer diameter of the steel pipe is 14~~426mm, and the wall thickness is not more than 45mm. The specific specifications are shown in Table 1 of GB/T17395-1998. According to the needs, after negotiation between the supply and demand parties, steel pipes with specifications other than those specified in Table 1 of GBT17395--1998 can be produced. 3.1.2 The allowable deviation of the outer diameter and wall thickness shall comply with the provisions of Table 1. Table 1 Allowable deviation of outer diameter and wall thickness
Type of steel pipe
Hot rolling (extrusion)
Ring (rolling)
Steel size
14~~ 30
>30~-50
In the past, the allowable deviation of the outer diameter of the hot-expanded steel pipe was ±1.0 and the allowable deviation of the smooth friction was ±16.
Allowable deviation
Ordinary grade
(minimum value is ±0.5mm) (minimum value is ±0.3mm)±1.0%
0.30mm
±0.75%
When the purchaser does not specify the allowable deviation level of steel pipe size in the contract, the allowable deviation of the outer diameter and wall thickness of the steel pipe shall comply with the specifications of the ordinary grade. According to the requirements of the purchaser, after consultation between the supply and demand parties and indicated in the contract, steel pipes with allowable dimensional deviations other than those specified in Table 1 can be produced. 3.2 Lengthwww.bzxz.net
3.2.1 Normal length
The normal length of the steel pipe is 4000~12000m1. After negotiation between the supply and demand parties, short-length steel pipes with a length of not less than 3000mm and not exceeding 5% of the total weight of the steel replacement delivery can be delivered: 3.2.2 Fixed length and multiple lengths
The fixed length and multiple length total length of the steel pipe should be within the range of the pass-band length, and the allowable deviation of the total length is +20mm.
Each multiple length should leave a cut margin according to the following provisions:Outer diameter ≤ 159 mm
Outer diameter ≥ 159 mm
3.3 Curvature
5~10 mm;
The curvature of the steel pipe should not exceed the following provisions:Wall thickness 15 mm ..........
Wall thickness>15~30mm*
Wall thickness ≥30 mm or outer diameter greater than 351 mm3.4 End shape
GB6479—2000
...........................
The end faces of both ends of the pipe should be perpendicular to the axis of the steel pipe, and the burrs on the cut should be removed. 3.5 Delivery weight
1.5 mm/m;
-. 2.0 mm/m,
.3.0mm/m.
Steel pipes are delivered according to actual weight or theoretical weight: the theoretical weight of steel pipes is calculated according to the provisions of GB/T17395, and the density of steel is 7. 85 kg/dm2.
According to the requirements of the purchaser, after consultation between the supply and demand parties and indicated in the contract, the deviation between the actual weight and theoretical weight of the delivered steel pipes shall comply with the following provisions:
Single steel pipe: ±10%,
Each batch of steel pipes with a minimum of 10 tons: ±7. 5%. 3.6 Marking example
Steel pipe with an outer diameter of 89 mm and a wall thickness of 6 mm made of grade 20 steel: a) Hot rolled (extruded) steel pipe, outer diameter and wall thickness are of ordinary grade precision, length is 4 000 mm 20-89 × 6 × 4000 - GB 6479-2000 b) Cold drawn (rolled) steel pipe, outer diameter is of high grade precision, wall thickness is of ordinary grade precision, length is 4 000 mm Cold 20-89 × 6 × 4 000 - GB 6479-2000 4 Technical requirements
4.1 Grade and chemical composition
The grade and chemical composition (melting analysis) of steel shall comply with the provisions of Table 2. The steel pipe shall be accepted according to the melting composition. 4. 1.1
Table 2 Steel grades and chemical composition
1oMWVNb
12CrMo
15CrMo
1Cr5Mo
12Cr2Mo
12SiMoVNb
0, 35 --
Residual element content in steel shall comply with the provisions of Table 3. 4. 1.2
Residual element content in Table 3
Nitrogen content in oxygen converter steel shall not exceed 0.008%. Residual elements, % shall not exceed
According to the requirements of the purchaser and specified in the contract, the carbon content of 20 steel for low temperature use shall be 0.17%~0.22%. 4. 1. 4
4.1.5 When the purchaser requires finished product analysis, it should be noted in the contract. The allowable deviation of the chemical composition of the finished steel pipe shall comply with the provisions of GB/T222.
4.2 Manufacturing method
The manufacturing method of steel and pipe shall comply with the provisions of YB/T5137. The steel pipe shall be manufactured by hot rolling (extrusion, expansion) or cold drawing (rolling) seamless method. When the purchaser specifies a certain manufacturing method, it should be noted in the contract. 4.3 Delivery status
The steel pipe shall be delivered after heat treatment according to the heat treatment system specified in Table 4. The heat treatment system shall be filled in the quality certificate. Table 4 Heat treatment system of steel pipe
12CrMe
15CrMo
12Cr2Mo
IoMowVNb
1Cr5Mo
12SiMoVNb
Heat treatment system
900℃～930℃ normalizing, 670℃～720℃ tempering, holding time, periodic furnace is more than 2h, continuous furnace is more than 1h930℃～960℃ normalizing, 680℃～720℃ tempering, holding time: periodic furnace is more than 2h, continuous furnace is more than 1h900℃～960℃ normalizing, 700℃～750℃ tempering. It can also be heated to 900℃~960℃ first, furnace cooled to 700℃, kept warm for more than 1h, air cooled to 970℃~990℃ normalized, 730℃~750℃ tempered, or 800℃~820℃ high temperature annealing
980℃~1020℃ normalized, 710℃~750℃ tempered Note: When the final rolling temperature of the hot rolled tube meets the normalizing temperature, it can replace the normalizing 4.4 Mechanical properties
4.4.1 The room temperature longitudinal mechanical properties of the steel pipe in the delivery state shall comply with the provisions of Table 5. Steel pipes with an outer diameter of not less than 57mm and a wall thickness of not less than 14mm shall be subjected to standard specimen U-notch impact test. The evaluation of the impact test results shall be in accordance with the provisions of GB/T17505. 823
12CrMo
15CrMo
12Cr2Mo
10MowVNb
1Cr5Mo
12SiMoVNb
tensile strength product
335~490
41 0~550
490-670
510~690
410~560
440~640
450~600
470~670
390~590
≥470
GB 6479—2000
Table 5 Mechanical properties of steel pipes
Limit point a
Elongation after fracture
Shrinkage of area
Impact energy Akl:2
Note: For steel pipes made of 12Cr2M steel, when the outer diameter is not more than 30mm and the thickness is not more than 3mm, the yield point is allowed to be reduced by 10MPa. For other grades, when the wall thickness is 16~40mm, the yield point is allowed to be reduced by 10MPa4.4.2 The manufacturer shall provide the Charpy (V-notch) low temperature impact test results of 10, 20 and 16Mn steel pipes. The test temperature shall be in accordance with the provisions of Table 6, and the impact energy shall not be a delivery condition.
According to the requirements of the purchaser, after negotiation between the supply and demand parties, and indicated in the contract, the test temperature and impact energy of the Charpy (V-notch) impact test of 10.20 and 16Mn steel pipes shall comply with the provisions of Table 6. 10 pipe can also be subjected to a 30°C Charpy (V-notch) impact test, the value of which shall be negotiated by both parties.
The evaluation of the impact test results shall be in accordance with the provisions of GB/T17505. Table 6 Low temperature impact performance
Impact energy Ak
Test temperature
Specimen direction
10×10×55
Specimen size
5×10×55
Note: When the outer diameter is not less than 57mm and the wall thickness is not less than 14mm, the standard size specimen shall be subjected to the impact test. When the outer diameter is not less than 49mm and the wall thickness is not less than 8mm, the small size specimen with a width of 5mm shall be subjected to the impact test. 4.5 Process performance
4.5.1 Hydraulic test
Hydraulic test shall be carried out on each steel pipe, and the test pressure shall be calculated according to formula (1). The maximum test pressure is 20MPa, and the pressure stabilization time is not less than 10s. Under the test pressure, the steel pipe shall not leak. P
-test pressure, MPa;
S—nominal wall thickness of steel pipe, m
-nominal outer diameter of steel pipe, mm!
GB 6479-2000
-allowable stress, MPa, which is 80% of the servo point value specified in Table 4. Eddy current flaw detection or magnetic flux leakage flaw detection can be used instead of hydraulic test at the manufacturer's option. When using eddy current flaw detection, the comparison sample pipe should adopt the acceptance level A in GB/T7735; when using magnetic flux leakage flaw detection, the longitudinal notch groove on the outer surface of the comparison sample pipe should comply with the provisions of L in GB/T12606, and the minimum groove depth is 0.5mm. 4.5.2 Flattening test
Except ICr5Mo steel pipes, all steel pipes with an outer diameter greater than 22 to 400 mm shall be subjected to a flattening test. The distance H between the plates after the steel pipe is flattened shall be calculated according to formula (2):
Rong La: s-
Nominal wall thickness of the steel pipe, mm;
D-Nominal outer diameter of the steel pipe, mm;
Deformation coefficient per unit length, which is 0.08. (1 +α)s
α+S/D
When S/D is greater than 0.15, the steel pipe may be subjected to a \C-shaped specimen flattening test. During flattening, the position of the \C\-shaped specimen between the two plates is shown in Figure 1.
After the flattening test, the specimen shall be free of cracks or splits. Figure 1 Position of C-shaped test specimen between two plates
4.5.3 Expansion test
According to the requirements of the purchaser and indicated in the contract, steel pipes with a wall thickness not exceeding 8mm can be subjected to expansion test. The expansion test is carried out at room temperature, and the top center taper is one of 30°, 45° or 60°. No cracks or fissures shall appear on the specimen after expansion. The expansion ratio of the outer diameter of the expanded specimen shall comply with the provisions of Table 7. Table 7
Temporary outer diameter expansion ratio of steel
Temporary outer diameter expansion of steel, %
High-quality carbon steel
Low alloy steel
Alloy steel
4.6 Low-power inspection
Inner diameter/outer diameter
>0. 6~0.8
Steel pipes directly rolled from ingots should be inspected at low magnification. There should be no visible white spots, inclusions, subcutaneous bubbles, skin folding and delamination on the acid immersion test piece of the cross-cured surface of the steel pipe.
4.7 Inspection of non-metallic inclusions
Steel pipes directly rolled from continuous casting or ingots should be inspected for non-metallic inclusions. The non-metallic inclusions of steel pipes shall be rated according to the A method and JK series rating chart in GB/T10561825
. GB6479-2000
A, B, C, D types of inclusions shall be judged according to the most serious one, and the level shall not be greater than 2.5 levels respectively. 4.8 Surface quality
There should be no cracks, folds, rolling folds, scars and delamination on the inner and outer surfaces of the steel pipe, and these defects shall be completely removed. The depth of removal shall not exceed the negative deviation of the nominal wall thickness, and the actual wall thickness at the cleaning location shall not be less than the minimum value allowed by the wall thickness deviation. On the inner and outer surfaces of the steel pipe, the allowable depth of the straight line is as follows: Cold drawn (rolled) steel pipe: not more than 4% of the wall thickness, and the maximum depth is 0.3mmt Hot rolled (extruded, expanded) steel pipe: not more than 5% of the wall thickness, and the maximum depth is 0.5mm. Other local defects that do not exceed the negative deviation of the wall thickness are allowed to exist. 4.9 No inspection
Steel pipes shall be ultrasonically inspected one by one in accordance with the provisions of GB/T5777. Comparing the longitudinal groove depth level of the outer surface of the sample pipe, cold drawn (rolled) steel pipes shall be implemented as C5, and hot rolled (extruded, expanded) steel pipes shall be implemented as C8. Other non-destructive testing can be added after consultation between the supply and demand parties. 5 Test method
5.1 The size and shape of the steel pipe shall be measured one by one using a measuring tool that meets the accuracy requirements. 5.2 The inner and outer surfaces of the steel pipe shall be visually inspected one by one under sufficient lighting conditions. 5.3 Other inspections of steel pipes shall comply with the requirements of Table 8. Table 8 Inspection items, test methods and sampling quantity of steel pipes No.
Inspection items
Chemical analysis
Tensile test
Impact test
Hydraulic test
Flattening test
Expansion test
Macro inspection
Non-metallic inclusions
Sonic wave flaw detection
Eddy current flaw detection
Magnetic flaw detection
Inspection rules
Inspection and acceptance
Test methods
GB/T 222
GB/T 223
GB/T 4336
GB/T 228
GB/T 229
GB/T 241
GB/T 246
GB/T242
GB/T 226
GB/T 1979
GB/F10561
GB/T 5777
GB/T 7735
GB/T 12606
Number of samples
1 sample from each furnace (tank)
1 sample from each of the two steel pipes for each batch
3 samples from each of the two steel pipes for each batch
1 sample from each of the two steel pipes for each batch1 sample from each of the two steel pipes for each batch
1 sample from each of the two steel pipes for each batchThe inspection and acceptance of each steel pipe shall be carried out by the supplier's technical supervision department. 6.2 Batch rules
Steel pipes shall be inspected and accepted in batches. Each batch shall consist of steel pipes of the same brand, same furnace () number, same specification and same heat treatment system (furnace). The number of steel pipes in each batch shall not exceed the following provisions:826
GB6479-2000
Outer diameter not more than 70mm, and wall thickness not more than 3mmOuter diameter greater than 351mm
Other sizes
6.3 Sampling quantity
The sampling quantity for each performance test of each batch of steel pipes shall be carried out in accordance with the provisions of Table 8. 6.4 Re-inspection and judgment rules
The re-inspection and judgment rules of steel pipes shall comply with the provisions of GB/T2102 and GI3/T17505.7 Packaging, marking and quality certificate
The packaging, marking and quality certificate of steel pipes shall comply with the provisions of GB/T2102. 400 strands;
50 strands;
200 strands.
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