This standard specifies the technical requirements, test methods and inspection rules, marking, packaging, transportation and storage of aluminum plate-fin heat exchangers with a design pressure of no more than 6.3MPa and a design temperature of -270~150℃, which are manufactured by salt bath brazing or vacuum brazing for gas separation and liquefaction equipment, petrochemical equipment and mechanical power devices. This standard applies to aluminum plate-fin heat exchangers. Heat exchangers manufactured by other brazing processes can also refer to it. JB/T 7261-1994 Technical conditions for aluminum plate-fin heat exchangers JB/T7261-1994 Standard download decompression password: www.bzxz.net

Machinery Industry Standard of the People's Republic of China
JB/T 7261-1994
Aluminum Plate-Fin Heat Exchanger
Published on July 18, 1994
Technical Conditions
Implementation on July 1, 1995
Ministry of Machinery Industry of the People's Republic of China
Subject Content and Scope of Application
Cited Standards
3 Technical Requirements
4 Test Methods and Inspection Rules
Marking, Packaging, Transportation and Storage
Appendix A
Performance Test Methods for Aluminum Plate-Fin Heat Exchangers (Supplement) |tt||Machinery Industry Standard of the People's Republic of China
Aluminum Plate-Fin Heat Exchanger
Subject Content and Scope of Application
Technical Conditions
JB/T7261-1994
This standard specifies the technical requirements, test methods and inspection rules, marking, packaging, transportation and storage of aluminum plate-fin heat exchangers with a design pressure not exceeding 6.3MPa and a design temperature of -270~150℃ manufactured by salt bath brazing or vacuum brazing for gas separation and liquefaction equipment, petrochemical equipment and mechanical power units. This standard applies to aluminum plate-fin heat exchangers (hereinafter referred to as heat exchangers). Heat exchangers manufactured by other brazing processes may also be implemented as a reference. Cited Standards
GB1804
GB2624
GB3193
GB3194
GB3197
GB 3614
GB3880
GB3881
GB4436
GB4437
GB6892
GB6893
GB/T13306
GB/T13384
JB1580
JB/Z167wwW.bzxz.Net
Technical requirements
General tolerances Unspecified tolerances for linear dimensions
Flow measurement throttling devices
Aluminum and aluminum alloy hot-rolled plates
Aluminum and aluminum alloy Dimensions and allowable deviations of aluminum platesAluminum and aluminum alloy wire for welding rods
Aluminum alloy foil
Aluminum and aluminum alloy plates
Aluminum alloy plates for brazing
Dimensions and allowable deviations of aluminum and aluminum alloy pipesAluminum and aluminum alloy hot extrusion pipes
Industrial aluminum and aluminum alloy hot extrusion profiles
Industrial aluminum and aluminum alloy drawing (rolling) pipe labels
General technical conditions for packaging of electromechanical products
Technical conditions for aluminum welding containers
Argon arc welding process regulations for aluminum air separation equipmentProduct performance requirements should meet the requirements of Table 1. Approved by the Ministry of Machinery Industry on July 18, 1994
Implemented on July 1, 1995
Cleanliness (CL-increment) D), 10-6
Switchable heat exchanger switching channel
JB/T 7261-1994
Factory inspection
On-site inspection
Deviation of non-switching channels and other heat exchangers from design values
Deviation of gas resistance values ​​of two switching channels in the same unit of switching heat exchangerOn-site inspection of heat exchanger temperature difference
On-site inspection of CO in the outlet air of switching heat exchanger, residual amount, 10-6Switching heat exchanger body expansion rate
(dew point)
Final dryness
Vacuum inspection
Nitrogen mass spectrometry inspection
Fin bursting test pressure3)
Note; 1) Cleanliness inspection is applicable to products manufactured by salt bath brazing method. Factory inspection
Unit length
Unit length
Pressure channel
Unpressurized channel
Unit symbol
Pa · L/s
Performance index
2700~3000
Not greater than design value
Not greater than design value
≤1×10
≤1.33×10-
Not less than 5 times of design pressure
2) The resistance value is the value under the test conditions of gas mass flow rate G=5kg/(m2·s), temperature of 20℃ and pressure of 101.325kPa. If the test conditions change, the test results should be converted accordingly. 3) Cleanliness (CL-1 increment) and CO2 residue in the table are expressed in volume fraction. 3.2
All materials should have material certificates issued by the material manufacturer. The materials and specifications of heat exchanger materials should comply with the relevant standards. If the material certificate is incomplete or the heat exchanger manufacturer has doubts about its quality, it should be re-tested according to the relevant standards. 3.2.2
The material grades and status of the main parts are shown in Table 2. Table 2
Parts name
Fin, guide vane
Head, connecting pipe
No. 21 anti-rust aluminum
No. 21 anti-rust aluminum
No. 2 brazing aluminum
No. 3 brazing aluminum
No. 21 anti-rust aluminum
No. 2 anti-rust aluminum
No. 4 anti-rust aluminum
Brand and status
LF21-M
LF21-R
LQ2-Y2
L03-Y2
LF21-M
Standard number
GB 3614
GB3880
GB 6892
GB3193
GB3194
GB 4436 GB 4437
JB/T 7261-1994
3.2.3 Wire materials for welding rods shall comply with the provisions of GB3197. 3.2.4 The silicon content of the composite layer of the partition plate for salt bath brazing is 6.8%~8.2%; the thickness of the single side of the composite layer of the partition plate is 0.10~0.14mm. When there is no bimetallic plate, LF21-M plus LT13 welding sheet can be used as a substitute. 3.3 Manufacturing accuracy of parts
The dimensional deviation and geometric tolerance of brazing components are shown in Table 3. Table 3
Guide vane
Inspection items
Verticality of wing side
Cut distance
Lateral bending S
Plane bending H
Twist (Nh)
Guide vane
Number of twists per meter length
Within 300 length, $0.5
Full length (L) range, S=U1000
L≤3300
L>3300
L≤1000
L≤3300
L≥3300
Inspection items
Length (width)
For Angle line length
Flatness
JB/T7261-1994
Continued Table 3
1000L≤3300
L>3300
L≤500
500≤L≤1000
1000≤L≤3300
L>3300
L≤1000
1000≤L≤3300
L>3300
h/L≤0.7%
The wall thickness of the head after forming shall not be less than 85% of the thickness specified in the drawing, and the difference with the thickness specified in the drawing shall not be greater than 3mm. The limit deviation of dimensions without tolerances shall be in accordance with the provisions of GB/T1804: machined parts shall be in accordance with m (medium grade), and non-machined parts shall be in accordance with 3.3.3
e (rough grade).
The dimensional tolerance of pin-welded components shall be based on the inspection of parts during assembly before pin-welding, and other parts shall be based on the measurement during assembly after pin-welding. 3.4
Manufacturing requirements
3.4.1 Assembly of brazed components
1 After the brazed components are formed, burrs shall be removed, and there shall be no serious knocks, scratches, or bumps on the surface. 3.4.1.1
2 The fin shape of the fins and guide vanes after forming shall remain flat and not be squeezed, stretched, or twisted: If the geometric shapes of the fins, guide vanes, and seals do not meet the requirements in part, they shall be reshaped. 3.4.1.3
The partition should be flat, without any bends, arches, small corner wing ridges and white edges without coating layer; the local intaglio depth on the plate surface
shall not exceed 10% of the plate thickness, and the maximum depth shall not exceed 0.15mm. 4
JB/T7261-1994
3.4.1.4 Before assembly, each brazing component should be cleaned, and impurities such as oil stains and rust spots should be thoroughly removed, and then dried. 3.4.1.5 During assembly, each brazing component in each layer should be close to each other, but not overlapped. Splicing gap: When the design pressure p≤2.5MPa, it shall not be greater than 1.5mm, locally no more than 3mm; when p>2.5MPa, no more than 1mm, locally no more than 2mm. 3.4.2 Appearance of plate bundle after brazing
3.4.2.1 Each brazing seam on the plate bundle should be full and smooth, and there should be no phenomenon of brazing material blocking the channel. 3.4.2.2 The fins of the guide port and the guide vane should be regular and should not be exposed outside the partition. 3.4.2.3 The inner concave and outer elastic amount between adjacent upper and lower seals shall not exceed 3mm. 3.4.2.4 The misalignment of the upper and lower planes caused by the needle welding of the plate bundle shall not exceed 1.5mm in every 100mm height, but the total thickness misalignment between the two side plates shall not exceed 8mm.
3.4.3 Assembly after welding
After the plate bundle is welded with the head and the pipe, it becomes a unit body. The axial position of the main pipe and the flange surface are measured based on the geometric axis of each surface of the plate bundle. The tolerance requirements for the assembly of the heat exchanger unit body at the pipe end or flange surface shall be as specified in the drawing. If there is no indication, it shall be in accordance with the requirements of Figure 1 and Table 4. +0.55H
Basic size
≤500
>500~3300
≤500
>500~1000
JB/T 7261-1994
Basic size
≤500
>500~2000
≤500
The pipe mouth or flange surface should be perpendicular to the main axis centerline of the pipe or unit body. The installation of the pipe flange should ensure that the flange surface is horizontal or vertical (if there are special requirements, it should be in accordance with the drawings). The deviation 4T shall not exceed 1% of the flange outer diameter (when the flange outer diameter is less than 100mm, it shall be calculated as 100mm) and shall not exceed 3mm.
The flange bolt through hole should be arranged in the middle of the main axis of the pipe or the plumb line (see Figure 2). When there are special requirements, they should be indicated on the drawings. 32
5 Hydrogen arc welding and weld flaw detection
3.4.5.1 When arc welding is required for the heads and pipes of heat exchangers, in addition to complying with the provisions of this standard, they should also comply with the relevant provisions of JB1580 and JB/Z167.
: The surface of the plate bundle that is welded for welding heads should be carefully visually inspected, and no surface defects such as cracks and pores should be present. 3. 4. 5.2
3.4.5.3 When the butt welds of the heads and pipes need to be inspected by X-ray flaw detection, the flaw detection length and film evaluation standard shall be implemented in accordance with JB1580 when the design pressure p≤1.6MPa: when p>1.6MPa, it shall be agreed upon by the supply and demand parties. The flaw detection rate of the switching heat exchanger heads in air separation equipment is 100%, and the film evaluation standard shall be in accordance with the provisions of JB1580. 3.4.5.4 For the main welds that cannot be inspected by radiographic inspection, the weld structure should be adopted and the surface color inspection should be carried out. There shall be no surface defects such as cracks, delamination and pores. 3.4.6
Surface defects and their repair
3.4.6.1 Surface defects of the unit body are allowed to exist if they do not affect the performance and life of the product and do not seriously affect the appearance of the product. The allowable scratch depth of the unit body surface: the head and the pipe shall not exceed 0.5mm; the plate bundle shall not exceed 2mm, and the total defect area on the surface of one surface shall not exceed 0.2% of the area. 3. 4. 6. 2
If the weld is found to have leakage or the flaw detection fails after the pressure test, repair welding is allowed. However, the number of repairs on the same part shall generally not exceed 3. 4. 6.3||t ​​... 6
JB/T7261-1994
3.4.6.4 For the switching heat exchanger, main heat exchanger, condenser evaporator and unit body of the heat exchanger with design pressure greater than 2.5MPa in the air separation equipment, the allowable repair welding length of the brazing seam shall not exceed 1% of the total length of the seal strip on the surface, and less than 3% for other heat exchangers. 3.4.7 Painting and surface treatment
The outer surface of the product should be cleaned of oil and dirt. Painting and other anti-corrosion treatments shall be in accordance with the provisions of the design drawings and relevant technical documents.
3.4.8 Nitrogen sealing
The heat exchanger channel after drying should be nitrogen sealed, and the ammonia sealing pressure is 0.02~0.05MPa. For the diffused channel that cannot be nitrogen sealed, corresponding protective measures should be taken.
4 Test methods and inspection rules
4.1 The test methods of heat exchangers shall comply with the provisions of the "Regulations on Safety Technical Supervision of Pressure Vessels" and Appendix A (Supplement) of this standard. 4.2 The inspection and testing of heat exchangers shall generally be carried out in the manufacturer, except for the relevant items that are required to be carried out on site. Each heat exchanger must be inspected and qualified by the manufacturer's technical inspection department and accompanied by a product certificate before it can be shipped. 4.3 Inspection and test items of heat exchangers
4.3.1 Cleanliness test
The cleanliness test shall be carried out on the plate bundle manufactured by the salt bath brazing method and shall comply with the provisions of Table 1. 4.3.2 Pressure test
The pressure test of heat exchangers shall generally comply with the provisions of the "Regulations on Safety Technical Supervision of Pressure Vessels", except for special provisions in this standard or design drawings.
Pressure test
The pressure test of heat exchanger includes hydraulic and gas pressure test. For heat exchangers not suitable for hydraulic test, gas pressure test can be used, but the butt welds must be inspected by 100% radiographic flaw detection before gas pressure test: the other welds should adopt the weld penetration structure and be inspected by color flaw detection; necessary safety measures should be taken during pressure test to ensure safety. 4.3.2.1.1 Hydraulic test
The hydraulic test of heat exchanger should generally use water as the test medium, and the water must be clean. Test pressure: The switching channel of the switching heat exchanger in the air separation equipment is 1.6MPa: The nitrogen channel of the condenser evaporator is 1.2MPa: The other channels are 1.5 times the design pressure: When the design pressure is less than 0.1MPa, no hydraulic test is required. 4.3.2.1.2 Air pressure test
The test pressure of a single heat exchanger is 1.25 times the design pressure; for heat exchangers assembled in series or parallel, it is 1.15 times the design pressure. 4. 3.2.2
Air tightness test
The air tightness test pressure of the heat exchanger: the test pressure of the switching channel of the switching heat exchanger and the nitrogen channel of the condenser evaporator is 0.7MPa. The test pressure of other heat exchangers is 1.1 times the design pressure. 4.3.3 Volume expansion test
The switching channel of the switching heat exchanger in the air separation equipment or the channel with specific requirements specified in the drawings shall be subject to this test. This test is carried out at the same time as the water pressure test, and the test pressures of the two are the same. The volume expansion rate of the switching heat exchanger shall comply with the provisions of Table 1. 4.3.4 Gas resistance test
JB/T7261-1994
The gas resistance test of the relevant channels of the heat exchanger shall be carried out according to the requirements of the design drawings. The test conditions and requirements shall be in accordance with the provisions of Table 1 or the design drawings. For the switching channels of the switching heat exchanger in the air separation equipment, in addition to testing its own resistance value, it shall also meet the requirements of the mutual resistance difference between the two.
The calculation of the allowable value of the resistance difference of the switching heat exchanger is as follows. 4.3.4.1 In the same unit (cold section or hot section), the resistance deviation of the two switching channels (A, B) is calculated according to formula (1). P±-1)×100%≤8%
Where: Ap is larger
The larger gas resistance value of the A and B channels (the same below); -The smaller gas resistance value of the A and B channels (the same below). (1)
4.3.4.2 When the cold and hot sections are combined into a group (including an integral heat exchanger with a cold and hot section), the total resistance deviation of the two switching channels in the group is calculated according to formula (2).
AP±-1）×100%≤2.4%
+...++....(2)
4.3.4.3 After several groups are combined into a large group, the deviation between the resistance value of each channel in the group and the average resistance value of the corresponding channel is calculated according to formula (3).
-1）×100%≤±4%
Where: Ap
Gas resistance value of a channel under test:
The average resistance value of a channel under test is calculated according to formula (4). 4p
Where: N——Number of groups in the combination of hot and cold sections. N
4.3.5 After the heat exchanger is manufactured, a drying inspection is carried out, which shall comply with the provisions of Table 1. 4.3.6 Vacuum and hydrogen mass spectrometry inspection
This test is only carried out when specified in the heat exchanger design drawing or supply contract, and the leakage rate is in accordance with the provisions of Table 1. 4.3.7 Fin burst test
When the heat exchanger adopts new fins and new brazing process, the fin burst test should be carried out. When the test piece bursts, the burst pressure should not be less than 5 times the design pressure, and the fin is qualified when it is pulled off. 5 Marking, packaging, transportation and storage
5.1 Marking
The product label should be fixed in a conspicuous position and the label should comply with the provisions of GB/T13306. The product label should at least include the following content: a.Product model:
b. Product name:
c. Main technical characteristics and parameters:
d. Manufacturing date;
e. Manufacturer name.
5.2 Packaging
JB/T7261-1994
5.2.1 Product packaging shall comply with the provisions of GB/T13384. 5.2.2 The following documents shall be accompanied by the product when it leaves the factory: Packing list;
b. Pressure vessel quality certificate;
c. Product qualification certificate:
d. Product completion drawing.
5.3 Transportation and storage
The transportation of products shall comply with the requirements of railways, roads and waterways. 5.3.1
The product shall be protected from collision and rain during transportation. 5.3.2
The product should be stored in a clean, dry place without corrosive media such as acid and alkali. It should not be stored in the open air. During the storage period, the nitrogen sealing pressure of each channel of the product should not be lower than 0.02MPa, otherwise dry nitrogen should be used to replenish the nitrogen sealing pressure.
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