GB/T 8259-1987 Technical requirements for clamp-type flexible pipe joints
Some standard content:
National Standard of the People's Republic of China
Technical conditions for clamp-type flexible pipe joints
Specification for flexible
coupling of housing
UDC 621. 643. 4
GB 8259-87
This standard applies to pipe joints specified in GB8260-87-Clamp-type flexible ring-type pipe joints" and GB8261-87-Clamp-type flexible shoulder-type pipe joints".
Technical requirements
1.1 Clamp-type flexible pipe joints shall comply with the requirements of this standard and be manufactured in accordance with the drawings approved by the prescribed procedures. 1.2 The material grades of the clamps and end pipes and the standards they should comply with are shown in Table 1. Table 1. Clamp and end pipe material
Part name
Nominal pressure, MPa(kgr/cm*）
1. 6(16. 3),2. 5(25. 5),4. 0(40, 8)QT42-10
KT85-10
10 molybdenum or 20 steel
10(102)
QT50-5
Standard number
GB 1348-78
GB 978—67
GB979—67
YB 231—79
GB 979- 67
1.2.1 In addition to the materials specified in Table 1, other materials may be selected according to requirements and agreed upon by both parties, but the mechanical properties shall not be lower than the mechanical properties of the materials specified under the corresponding pressure in Table 1.
1.2.2 The metallographic structure of ductile iron shall not be lower than the Grade 2 standard in JB1802-76 rare earth magnesium ductile iron metallographic standard\. 1.3 The technical requirements of bolts shall comply with the provisions of GB 8262-87 "Round head oval neck bolts", and their mechanical properties shall comply with Grade 6.8 of GB 3098.1-82 "Mechanical properties of fasteners bolts, screws and studs". Nuts shall comply with the provisions of GB 52-76 "Angle nuts\", and their mechanical properties shall comply with Grade 6 of GB3098.2-82 "Mechanical properties of fasteners nuts". 1.4 Castings are not allowed to have pores, sand holes, slag inclusions, slits, shrinkage holes and cracks that affect the mechanical properties. 1.5 The castings shall be cleaned and shaped, and their dimensional tolerances shall not exceed those specified in the drawings. Burrs are not allowed on the castings. 1.6 The casting end pipes may be coated with a curing impregnant after processing to prevent the curing micropores from loosening and leaking. 1.7 The inner and outer surfaces of the clamps shall be coated with anti-rust primer, and the outer surface shall be coated with a layer of oily blending; the surface paint layer shall be smooth, and no bubbles with a diameter greater than 2 mm or paint blocks with a thickness greater than 2 mm shall be allowed to accumulate. 1.8 The material of the rubber sealing ring shall be selected according to Table 2. Approved by the Ministry of Carbon Baking Industry of the People's Republic of China on September 1, 1987, and implemented on May 1, 1988
Natural rubber
Synthetic rubber
Silicone rubber
GB 8259—87
Table 2 Rubber sealing ring materials
Applicable media
Air, water
Air, water, mineral oil, coal gas, medicinesmineral oil, coal gas, medicines
The physical and mechanical properties of various types of rubber shall conform to the requirements of Table 3, Table 4 and Table 5. 1.9
Physical and mechanical properties of natural rubber
50~175
200-1000
50~175
200~1000
Shore A
Shore A
MPa(kgt/cm)
Tear strength at break
MPe[kgf/cm')
Shore A
Batch breaking strength
Tear breaking strength
MPa(kgf/cm2)
215(153)
215(153)
Tear breaking elongation
Table 4 Physical and mechanical properties of rubber
Tear breaking elongation
Oil resistance (volume change)
Applicable temperature
-20~1 80℃
-20℃-+140℃
40℃~+230℃
200% tensile strength
MPat(kgf/cm2)
25(51)
Heat resistance change
70 h,100 ℃
" No. standard oil
-10～+5
Table 5 Physical and mechanical properties of silicone rubber
Tear elongation
Heat aging resistance
70h, 232℃
. Strength
Tear elongation
Oil resistance (No. 1 standard oil)
70h, 150℃
The sealing surface of the rubber sealing ring shall not be allowed to have bubbles, impurities, cracks and uneven defects. The non-sealing surface of the rubber sealing ring shall comply with the provisions of Table 6. Tear resistance
Compression deformation
Compression deformation
GB8259--87
Table 6 Defects on non-sealing surface of rubber sealing ring
Nominal diameter Ds, mm
50~200
Bubble length and width are not more than 2mm, depth
not more than 0.5 mm, not more than 2 places Impurity length is not more than 2 mm, not more than 1 mm, depth is not more than 1 mm, not more than 3 places
Concave and convex depth or height is not more than
225~500
Bubble length and width are not more than 2 mm, depth
not more than 1 mm, not more than 3 places
Impurity length and width are not more than 2 mm, depth
not more than 1mm, not more than 3 places
the depth or height of the four convexities is not more than
600--1000
the length and width of the air filter are not more than 2mm, the depth
not more than 1 mm, not more than 4 places
the length and width of the impurities are not more than 2mm. The depth
is not more than 2mm, not more than 4 places
the depth or height of the concave and convex is not more than
1mm, the length is not more than 1mm, not more than 5mm, the length is not less than 5mm, not more than 10mm, not more than 3 places
more than 4 places
more than 5 places
not allowed
the width and length, the depth is not more than 0. 5 mm, the depth of the damage is allowed to be no more than 0. 5 nm, the length is not more than 5 mm, the width is not more than 1 mm, not more than 3 The length shall not exceed 5 mm, the width shall not exceed
The length shall not exceed 10 mm, the width shall not exceed
The length shall not exceed 10 mm, the width shall not exceed
1mm, the depth shall not exceed 0.5mm, not more than 2mm, the depth shall not exceed mm, not more than 2mm, the depth shall not exceed mm, not more than 4 places
more than 3 places
1.12 For joints installed on fixed pipes, if they are not disassembled and the sealing ring is used at normal temperature, its service life can generally exceed 10 years
1.13 The rubber brand, nominal diameter, manufacturing year and month, and factory mark should be marked on the non-sealing surface of the rubber sealing ring. 2 Test method
2.1 Negative pressure sealing and leakage rate inspection
The principle of the inspection device is shown in Figure 1. The valve uses a vacuum manual valve. The diameter of the exhaust pipe is not more than 50mm. The inner surface of the pipe and the joint should be dry and clean. A vacuum gauge with a precision of 1.5 should be selected and calibrated. The weld between the head and the end pipe should be smooth and no leakage is allowed. When the vacuum degree reaches 0.08 MPa (600 mmHg) or above, continue to exhaust for 30 minutes, then close the butterfly valve. When the vacuum degree is higher than 0.08MPa (600 mmHg), select △ and record the corresponding &t. The leakage rate Q (MPa/s) is calculated according to formula (1): AP
Where 4P
The pressure difference between two adjacent wall measurements, MPa1
The time measured when the pressure increases by AP, s. After multiple measurements, the maximum leakage rate shall not exceed 0.5×10-\MPa/s(0.4 mmHg/s). 1)
Vacuum gauge
GB 8259 B7
Its vacuum manual butterfly business
The cell is cut off by the sugar energy of the fine self-energy energy energy; the blood is with the blood energy of the disease energy of the energy of the room Figure 1 Schematic diagram of the vacuum degree and leakage rate inspection device Sealing performance and pressure resistance inspection
Inspection pipe installation principle See Figure 2.
Figure 2 Schematic diagram of the sealing performance and pressure resistance inspection device Vacuum pipe
White air source
During the test, the air in the system should be removed, and then pressurized with a water pump. When the pressure gradually rises from 0 (gauge pressure) to 0. 1MPa (1kgf/cm2), close the valve and observe for no less than 5 minutes. When there is no leakage in the joint, continue to increase the pressure to 1.5 times the nominal pressure. At this time, the joint should not leak, the bolts should not be elongated, the card deformation, and the end pipe should not fall out of the clamp. If the above situation occurs, the inspection is considered unqualified.
2.3 Angle inspection
The principle of the angle inspection device is shown in Figure 3.
When the joint reaches the allowable angle without any deformation under the action of external force, it is considered qualified. The joint angle 8 is calculated according to formula (2): B=aresinido0
Where: at-
The moving distance of the pipe end, mm.
+-+(2)
2.4 Maximum pipe end gap inspection
GB8259-87
Figure 3 Schematic diagram of the angle inspection device
The principle of the maximum pipe end gap inspection device is shown in Figure 1. Figure 4 Principle of the maximum pipe end clearance inspection device
External force
GB 8259-87
During the test, a steel plate cap should be welded to both ends of the end pipe, and the pipe end clearance should be 0, and then 1% pressure water with a low nominal pressure should be introduced. After the end pipe is moved, Z is measured again. The maximum pipe end clearance 4 (mm) is calculated according to formula (3): dL-
Where: L
The length measured when the pipe end clearance is 0, mm, and the length measured when the pipe end clearance reaches the maximum, mm. The value in the figure shall not be less than the maximum allowable pipe end clearance. 3 Inspection rules
The ordering unit may conduct random inspections on the products delivered by the manufacturer according to this standard, and determine whether the batch of products delivered is qualified. 3.7
To determine acceptance or rejection, the inspection items shall be carried out in accordance with the requirements of Table 7 and Article 3.5. Technical requirements other than those listed in this standard shall be controlled by the manufacturer, or the ordering unit and the manufacturer shall discuss the inspection method. Table 7 Sampling plan Sampling plan 1 Inspection items Appearance and main dimensions Inspection of the corner and the largest section End clearance inspection Vacuum degree inspection Leakage rate inspection Seal and pressure strength inspection Number of first sampling inspection; Number of second sampling inspection. A. Number of qualified judgments; First qualified judgment number, First unqualified judgment number; Second unqualified judgment number.
Qualified quality level
Batch size
2150--500
150--500
150～500
>150~~500
Book size
m/n:
Judgment number
3.2 The factory inspection of the manufacturer can be carried out by the factory's quality inspection department according to the corresponding product technical requirements and the sampling method of this standard, and the product certificate will be issued for each qualified batch of products. 3.3 The manufacturer has the right to use other methods to conduct internal inspections, but the product quality must be guaranteed. 3.4 Sampling plan table
GB8259-87
The inspection work procedures of the sampling plan should comply with the provisions of GB2828-B1 "Batch inspection counting sampling procedures and sampling tables (applicable to the inspection of continuous batches)".
The batch range and corresponding sampling plan of each inspection item are shown in Table 7. Except for the joints on gas extraction or other negative pressure pipelines, which must be inspected for vacuum and gas leakage rate, other inspections are not required. 3.5 The inspection of fatal defects is a destructive inspection and should be carried out in accordance with Article 3.5 "Special provisions for fatal defects" in GB2828. 3.6 Explanation of sampling plan
3.6.1 The order of each inspection item should be carried out in the order specified in Table 7. Generally, the inspection of the next item should be carried out on the basis of the previous item being inspected and qualified.
3.6.2 If one of the items inspected is unqualified, the batch is unqualified. During the inspection process, if a certain indicator has been unqualified, there is no need to carry out the subsequent inspection items. 3.6.3 The orderer has the right to reject the unqualified products found during the inspection process, regardless of whether the product is part of the sample or whether the batch is judged to be accepted.
4 Packaging, storage and marking
4.1 The finished product should be free of dirt. Under normal transportation and storage conditions, it should be guaranteed not to rust for half a year from the date of leaving the factory. 4.2 The product should be packed before leaving the factory. The packaging materials can be selected according to the specific conditions of the manufacturer. However, under normal transportation and storage conditions, the parts shall not be damaged or lost due to improper packaging. 4.3 The rubber sealing ring should be packed separately, and the rubber should not be polluted, damaged or opaque. During transportation, it is strictly forbidden to contact with corrosive and harmful substances to rubber, and avoid direct sunlight and rain. The rubber sealing ring should be stored in a cool, dry, ventilated place away from heat sources.
4.4 The packaging surface should be attached with a label, the content of which is as follows: Manufacturer name:
b. Product name and specifications:
Manufacturing date or production batch number:
d. Product quantity.
4.5 The product inspection certificate and instruction manual should be attached. A.1 Installation method
A.1.1 Welding
GB8259-87
Appendix A
Installation and use instructions of the card-type flexible pipe joint (reference part)
Before installing the joint, weld the end pipe to the end of the pipe. Before welding, check the sealing surface of the end pipe and deal with the collision, scratches, burrs and dirt that affect the sealing effect.
A.1.1.1 The end face of the steel pipe should be perpendicular to its axis. A.1.1.2 Before welding, the rust and paint on the steel pipe and the end pipe weld should be removed. A,1. 1. 3 During welding, the steel pipe and the end pipe should remain coaxial. A.1.1.4 The end pipe uses a single-sided V-groove single-sided continuous weld and steel pipe butt welding. The recommended welding rod brand is T422. The weld line must not have defects such as pores, slag inclusions, cracks and incomplete penetration.
A.1.1.5 To protect the sealing surface from the impact of welding spatter, the end pipe sealing surface should be covered with a protective cover before welding. A.1.1.6 Connect the steel pipe with welded end pipes with a clamp-type flexible pipe joint for water pressure test. The test pressure is 1.5 times the working pressure. The observation time is not less than 5 minutes. If there is no leakage, it is qualified. A.1.2 After the pressure test is qualified, except for the sealing surface, the steel pipe should be painted with anti-rust paint according to different requirements. A.1.3 In order to prevent the sealing surface from being damaged, the sealing surface should be covered with a protective cover during the transportation of the steel pipe. The protective cover can be purchased from the factory. A.1.4 Before assembly, the sundries in the steel pipe should be removed. Special attention should be paid to clean the sealing surface smoothly, without dirt and scratches. A.1.5 During assembly, the two steel pipes should be aligned with the axis, and the sealing surface, the inner cavity of the card, the joint surface of the two ears, and the threaded part of the bolts should be coated with No. 1 calcium-based grease (vaseline) or other grease that does not damage the rubber seal ring. Keep a certain distance between the two pipe ends according to the installation requirements, and then install and adjust the seal ring to a moderate position. Tighten the bolts so that the bolts on both sides are evenly hooked to prevent biting the seal ring. A.1.6 After the joint is installed, under any circumstances, its rotation angle should not exceed the values specified in GB8260-87 "Clamp-type flexible ring-type pipe joint" and GB8261-87 "Clamp-type flexible shoulder-type pipe joint". When the joint needs to have a rotation angle, it should be assembled according to the straight pipe first, and then the pipe should be folded to achieve the predetermined rotation angle. A.1.7 The single-side lip width of the rubber seal ring (see Figure 1) is selected according to Table A1. Table A1
50~175
200～600
700~1000
Additional Notes:
GB825987
This standard is under the jurisdiction of Xi'an Coal Mine Design Institute of the Ministry of Coal Industry. This standard was drafted by Xi'an Coal Mine Design Institute of the Ministry of Coal Industry, and the main drafters of this standard are Shi Xiaoxuan and An Zichou. From the date of implementation of this standard, the original departmental standard MT35-79G.JJ, GJH type pipe joints" will be invalid.1MPa (1kgf/cm2), close the valve and observe for no less than 5 minutes. When there is no leakage in the joint, continue to increase the pressure to 1.5 times the nominal pressure. At this time, the joint should not leak, the bolts should not be elongated, the clamp should not be deformed, and the end pipe should not be out of the clamp. If any of the above situations occur, the inspection is considered unqualified.
2.3 Angle inspection
The principle of the angle inspection device is shown in Figure 3.
Under the action of external force, when the joint reaches the allowable angle without any deformation, it is considered qualified. The joint angle 8 is calculated according to formula (2): B=aresinido0
Where: at-
The distance the pipe end moves, mm.
+-+(2)
2.4 Maximum pipe end gap inspection
GB8259-87
Figure 3 Principle diagram of the corner inspection device
The principle diagram of the maximum pipe end gap inspection device is shown in Figure 1.
Figure 4 Principle diagram of the maximum pipe end gap inspection device
External force
GB 8259-87
During the test, a head made of steel plate should be welded to both ends of the end pipe, and the pipe end gap should be 0, measured 1%, and then pressure water with a low nominal pressure should be passed. After the end pipe moves, the maximum pipe end gap 4 (mm) is calculated according to formula (3): dL-
Where: L
The length measured when the pipe end gap is 0, mm, the length measured when the pipe end gap reaches the maximum, mm. The value of the figure shall not be less than the maximum allowable pipe end gap. 3 Inspection rules
Ordering units can conduct random inspections on products delivered by manufacturers according to this standard to determine whether the batch of products delivered is qualified or not. 3.7
To determine acceptance or rejection, the inspection items shall be carried out in accordance with the requirements of Table 7 and 3.5. Technical requirements other than the inspection date listed in this standard shall be controlled by the manufacturer, or the ordering unit and the manufacturer shall discuss the inspection method. Table 7 Sampling plan table
Sampling plan
Pei Zhong, 1
Inspection items
Appearance and main
Dimension inspection
Corner expansion maximum section
End clearance inspection
Vacuum degree inspection
Leakage rate inspection
Seal and pressure
Strength inspection
Number of first random inspections;
Number of second random inspections.
A. The first qualified judgment number;
The first qualified judgment number,
The first unqualified judgment number;
The second unqualified judgment number.
Qualified quality level
Batch size
2150--500
150--500
150～500
>150~~500
Book size
m/n:
Judgment number
3.2 The factory inspection of the manufacturer can be carried out by the factory's quality inspection department according to the corresponding product technical requirements and the sampling method of this standard, and the product certificate will be issued for each qualified batch of products. 3.3 The manufacturer has the right to use other methods to conduct internal inspections, but the product quality must be guaranteed. 3.4 Sampling plan table
GB8259-87
The inspection work procedures of the sampling plan should comply with the provisions of GB2828-B1 "Batch inspection counting sampling procedures and sampling tables (applicable to the inspection of continuous batches)".
The batch range and corresponding sampling plan of each inspection item are shown in Table 7. Except for the joints on gas extraction or other negative pressure pipelines, which must be inspected for vacuum and gas leakage rate, other inspections are not required. 3.5 The inspection of fatal defects is a destructive inspection and should be carried out in accordance with Article 3.5 "Special provisions for fatal defects" in GB2828. 3.6 Explanation of sampling plan
3.6.1 The order of each inspection item should be carried out in the order specified in Table 7. Generally, the inspection of the next item should be carried out on the basis of the previous item being inspected and qualified.
3.6.2 If one of the items inspected is unqualified, the batch is unqualified. During the inspection process, if a certain indicator has been unqualified, there is no need to carry out the subsequent inspection items. 3.6.3 The orderer has the right to reject the unqualified products found during the inspection process, regardless of whether the product is part of the sample or whether the batch is judged to be accepted.
4 Packaging, storage and marking
4.1 The finished product should be free of dirt. Under normal transportation and storage conditions, it should be guaranteed not to rust for half a year from the date of leaving the factory. 4.2 The product should be packed before leaving the factory. The packaging materials can be selected according to the specific conditions of the manufacturer. However, under normal transportation and storage conditions, the parts shall not be damaged or lost due to improper packaging. 4.3 The rubber sealing ring should be packed separately, and the rubber should not be polluted, damaged or opaque. During transportation, it is strictly forbidden to contact with corrosive and harmful substances to rubber, and avoid direct sunlight and rain. The rubber sealing ring should be stored in a cool, dry, ventilated place away from heat sources.
4.4 The packaging surface should be attached with a label, the content of which is as follows: Manufacturer name:
b. Product name and specifications:
Manufacturing date or production batch number:
d. Product quantity.
4.5 The product inspection certificate and instruction manual should be attached. A.1 Installation method
A.1.1 Welding
GB8259-87
Appendix A
Installation and use instructions of the card-type flexible pipe joint (reference part)
Before installing the joint, weld the end pipe to the end of the pipe. Before welding, check the sealing surface of the end pipe and deal with the collision, scratches, burrs and dirt that affect the sealing effect.
A.1.1.1 The end face of the steel pipe should be perpendicular to its axis. A.1.1.2 Before welding, the rust and paint on the steel pipe and the end pipe weld should be removed. A,1. 1. 3 During welding, the steel pipe and the end pipe should remain coaxial. A.1.1.4 The end pipe uses a single-sided V-groove single-sided continuous weld and steel pipe butt welding. The recommended welding rod brand is T422. The weld line must not have defects such as pores, slag inclusions, cracks and incomplete penetration.
A.1.1.5 To protect the sealing surface from the impact of welding spatter, the end pipe sealing surface should be covered with a protective cover before welding. A.1.1.6 Connect the steel pipe with welded end pipes with a clamp-type flexible pipe joint for water pressure test. The test pressure is 1.5 times the working pressure. The observation time is not less than 5 minutes. If there is no leakage, it is qualified. A.1.2 After the pressure test is qualified, except for the sealing surface, the steel pipe should be painted with anti-rust paint according to different requirements. A.1.3 In order to prevent the sealing surface from being damaged, the sealing surface should be covered with a protective cover during the transportation of the steel pipe. The protective cover can be purchased from the factory. A.1.4 Before assembly, the sundries in the steel pipe should be removed. Special attention should be paid to clean the sealing surface smoothly, without dirt and scratches. A.1.5 During assembly, the two steel pipes should be aligned with the axis, and the sealing surface, the inner cavity of the card, the joint surface of the two ears, and the threaded part of the bolts should be coated with No. 1 calcium-based grease (vaseline) or other grease that does not damage the rubber seal ring. Keep a certain distance between the two pipe ends according to the installation requirements, and then install and adjust the seal ring to a suitable position. Tighten the bolts so that the bolts on both sides are evenly hooked to prevent biting the seal ring. A.1.6 After the joint is installed, under any circumstances, its rotation angle should not exceed the values specified in GB8260-87 "Clamp-type flexible ring-type pipe joint" and GB8261-87 "Clamp-type flexible shoulder-type pipe joint". When the joint needs to have a rotation angle, it should be assembled according to the straight pipe first, and then the pipe should be folded to achieve the predetermined rotation angle. A.1.7 The single-side lip width of the rubber seal ring (see Figure 1) is selected according to Table A1. Table A1
50~175
200～600
700~1000
Additional Notes:
GB825987
This standard is under the jurisdiction of Xi'an Coal Mine Design Institute of the Ministry of Coal Industry. This standard was drafted by Xi'an Coal Mine Design Institute of the Ministry of Coal Industry, and the main drafters of this standard are Shi Xiaoxuan and An Zichou. From the date of implementation of this standard, the original departmental standard MT35-79G.JJ, GJH type pipe joints" will be invalid.1MPa (1kgf/cm2), close the valve and observe for no less than 5 minutes. When there is no leakage in the joint, continue to increase the pressure to 1.5 times the nominal pressure. At this time, the joint should not leak, the bolts should not be elongated, the clamp should not be deformed, and the end pipe should not be out of the clamp. If any of the above situations occur, the inspection is considered unqualified.
2.3 Angle inspection
The principle of the angle inspection device is shown in Figure 3.
Under the action of external force, when the joint reaches the allowable angle without any deformation, it is considered qualified. The joint angle 8 is calculated according to formula (2): B=aresinido0
Where: at-
The distance the pipe end moves, mm.
+-+(2)
2.4 Maximum pipe end gap inspection
GB8259-87
Figure 3 Principle diagram of the corner inspection device
The principle diagram of the maximum pipe end gap inspection device is shown in Figure 1.
Figure 4 Principle diagram of the maximum pipe end gap inspection device
External force
GB 8259-87
During the test, a head made of steel plate should be welded to both ends of the end pipe, and the pipe end gap should be 0, measured 1%, and then pressure water with a low nominal pressure should be passed. After the end pipe moves, the maximum pipe end gap 4 (mm) is calculated according to formula (3): dL-
Where: L
The length measured when the pipe end gap is 0, mm, the length measured when the pipe end gap reaches the maximum, mm. The value of the figure shall not be less than the maximum allowable pipe end gap. 3 Inspection rules
Ordering units can conduct random inspections on products delivered by manufacturers according to this standard to determine whether the batch of products delivered is qualified or not. 3.7
To determine acceptance or rejection, the inspection items shall be carried out in accordance with the requirements of Table 7 and 3.5. Technical requirements other than the inspection date listed in this standard shall be controlled by the manufacturer, or the ordering unit and the manufacturer shall discuss the inspection method. Table 7 Sampling plan table
Sampling plan
Pei Zhong, 1
Inspection items
Appearance and main
Dimension inspection
Corner expansion maximum section
End clearance inspection
Vacuum degree inspection
Leakage rate inspection
Seal and pressure
Strength inspection
Number of first random inspections;
Number of second random inspections.
A. The first qualified judgment number;
The first qualified judgment number,
The first unqualified judgment number;
The second unqualified judgment number.
Qualified quality level
Batch size
2150--500
150--500
150～500
>150~~500
Book size
m/n:
Judgment number
3.2 The factory inspection of the manufacturer can be carried out by the factory's quality inspection department according to the corresponding product technical requirements and the sampling method of this standard, and the product certificate will be issued for each qualified batch of products. 3.3 The manufacturer has the right to use other methods to conduct internal inspections, but the product quality must be guaranteed. 3.4 Sampling plan table
GB8259-87
The inspection work procedures of the sampling plan should comply with the provisions of GB2828-B1 "Batch inspection counting sampling procedures and sampling tables (applicable to the inspection of continuous batches)".
The batch range and corresponding sampling plan of each inspection item are shown in Table 7. Except for the joints on gas extraction or other negative pressure pipelines, which must be inspected for vacuum and gas leakage rate, other inspections are not required. 3.5 The inspection of fatal defects is a destructive inspection and should be carried out in accordance with Article 3.5 "Special provisions for fatal defects" in GB2828. 3.6 Explanation of sampling plan
3.6.1 The order of each inspection item should be carried out in the order specified in Table 7. Generally, the inspection of the next item should be carried out on the basis of the previous item being inspected and qualified.
3.6.2 If one of the items inspected is unqualified, the batch is unqualified. During the inspection process, if a certain indicator has been unqualified, there is no need to carry out the subsequent inspection items. 3.6.3 The orderer has the right to reject the unqualified products found during the inspection process, regardless of whether the product is part of the sample or whether the batch is judged to be accepted.
4 Packaging, storage and marking
4.1 The finished product should be free of dirt. Under normal transportation and storage conditions, it should be guaranteed not to rust for half a year from the date of leaving the factory. 4.2 The product should be packed before leaving the factory. The packaging materials can be selected according to the specific conditions of the manufacturer. However, under normal transportation and storage conditions, the parts shall not be damaged or lost due to improper packaging. 4.3 The rubber sealing ring should be packed separately, and the rubber should not be polluted, damaged or opaque. During transportation, it is strictly forbidden to contact with corrosive and harmful substances to rubber, and avoid direct sunlight and rain. The rubber sealing ring should be stored in a cool, dry, ventilated place away from heat sources.
4.4 The packaging surface should be attached with a label, the content of which is as follows: Manufacturer name:
b. Product name and specifications:
Manufacturing date or production batch number:
d. Product quantity.
4.5 The product inspection certificate and instruction manual should be attached. A.1 Installation method
A.1.1 Welding
GB8259-87
Appendix A
Installation and use instructions of the card-type flexible pipe joint (reference part)
Before installing the joint, weld the end pipe to the end of the pipe. Before welding, check the sealing surface of the end pipe and deal with the collision, scratches, burrs and dirt that affect the sealing effect.
A.1.1.1 The end face of the steel pipe should be perpendicular to its axis. A.1.1.2 Before welding, the rust and paint on the weld of the steel pipe and the end pipe should be removed. A,1. 1. 3 During welding, the steel pipe and the end pipe should remain coaxial. A.1.1.4 The end pipe uses a single-sided V-groove single-sided continuous weld and steel pipe butt welding. The recommended welding rod brand is T422. The weld line must not have defects such as pores, slag inclusions, cracks and incomplete penetration.
A.1.1.5 To protect the sealing surface from the impact of welding spatter, the end pipe sealing surface should be covered with a protective cover before welding. A.1.1.6 Connect the steel pipe with welded end pipes with a clamp-type flexible pipe joint for water pressure test. The test pressure is 1.5 times the working pressure. The observation time is not less than 5 minutes. If there is no leakage, it is qualified. A.1.2 After the pressure test is qualified, except for the sealing surface, the steel pipe should be painted with anti-rust paint according to different requirements. A.1.3 In order to prevent the sealing surface from being damaged, the sealing surface should be covered with a protective cover during the transportation of the steel pipe. The protective cover can be purchased from the factory. A.1.4 Before assembly, the sundries in the steel pipe should be removed. Special attention should be paid to clean the sealing surface smoothly, without dirt and scratches. A.1.5 During assembly, the two steel pipes should be aligned with the axis, and the sealing surface, the inner cavity of the card, the joint surface of the two ears, and the threaded part of the bolts should be coated with No. 1 calcium-based grease (vaseline) or other grease that does not damage the rubber seal ring. Keep a certain distance between the two pipe ends according to the installation requirements, and then install and adjust the seal ring to a suitable position. Tighten the bolts so that the bolts on both sides are evenly hooked to prevent biting the seal ring. A.1.6 After the joint is installed, under any circumstances, its rotation angle should not exceed the values specified in GB8260-87 "Clamp-type flexible ring-type pipe joint" and GB8261-87 "Clamp-type flexible shoulder-type pipe joint". When the joint needs to have a rotation angle, it should be assembled according to the straight pipe first, and then the pipe should be folded to achieve the predetermined rotation angle. A.1.7 The single-side lip width of the rubber seal ring (see Figure 1) is selected according to Table A1. Table A1
50~175
200～600
700~1000
Additional Notes:
GB825987
This standard is under the jurisdiction of Xi'an Coal Mine Design Institute of the Ministry of Coal Industry. This standard was drafted by Xi'an Coal Mine Design Institute of the Ministry of Coal Industry, and the main drafters of this standard are Shi Xiaoxuan and An Zichou. From the date of implementation of this standard, the original departmental standard MT35-79G.JJ, GJH type pipe joints" will be invalid.4 Maximum pipe end gap inspection
GB8259-87
Figure 3 Principle diagram of the corner inspection device
The principle diagram of the maximum pipe end gap inspection device is shown in Figure 1. Head
Figure 4 Principle diagram of the maximum pipe end gap inspection device
External force
GB 8259-87
During the test, a head made of steel plate should be welded to both ends of the end pipe, and the pipe end gap should be 0, measured 1%, and then pressure water with low nominal pressure should be passed. After the end pipe moves, the maximum pipe end gap 4 (mm) is calculated according to formula (3): dL-
Where: L
The length measured when the pipe end gap is 0, mm, -The length measured when the pipe end gap reaches the maximum, mm. The value of the figure shall not be less than the maximum allowable pipe end gap. 3 Inspection rules
Ordering units can conduct random inspections on products delivered by manufacturers according to this standard to determine whether the batch of products delivered is qualified or not. 3.7
To determine acceptance or rejection, the inspection items shall be carried out in accordance with the requirements of Table 7 and 3.5. Technical requirements other than the inspection date listed in this standard shall be controlled by the manufacturer, or the ordering unit and the manufacturer shall discuss the inspection method. Table 7 Sampling plan table
Sampling plan
Pei Zhong, 1
Inspection items
Appearance and main
Dimension inspection
Corner expansion maximum section
End clearance inspection
Vacuum degree inspection
Leakage rate inspection
Seal and pressure
Strength inspection
Number of first random inspections;
Number of second random inspections.
A. The first qualified judgment number;
The first qualified judgment number,
The first unqualified judgment number;
The second unqualified judgment number.
Qualified quality level
Batch size
2150--500
150--500
150～500
>150~~500
Book size
m/n:
Judgment number
3.2 The factory inspection of the manufacturer can be carried out by the factory's quality inspection department according to the corresponding product technical requirements and the sampling method of this standard, and the product certificate will be issued for each qualified batch of products. 3.3 The manufacturer has the right to use other methods to conduct internal inspections, but the product quality must be guaranteed. 3.4 Sampling plan table
GB8259-87
The inspection work procedures of the sampling plan should comply with the provisions of GB2828-B1 "Batch inspection counting sampling procedures and sampling tables (applicable to the inspection of continuous batches)".
The batch range and corresponding sampling plan of each inspection item are shown in Table 7. Except for the joints on gas extraction or other negative pressure pipelines, which must be inspected for vacuum and gas leakage rate, other inspections are not required. 3.5 The inspection of fatal defects is a destructive inspection and should be carried out in accordance with Article 3.5 "Special provisions for fatal defects" in GB2828. 3.6 Explanation of sampling plan
3.6.1 The order of each inspection item should be carried out in the order specified in Table 7. Generally, the inspection of the next item should be carried out on the basis of the previous item being inspected and qualified.
3.6.2 If one of the items inspected is unqualified, the batch is unqualified. During the inspection process, if a certain indicator has been unqualified, there is no need to carry out the subsequent inspection items. 3.6.3 The orderer has the right to reject the unqualified products found during the inspection process, regardless of whether the product is part of the sample or whether the batch is judged to be accepted.
4 Packaging, storage and marking
4.1 The finished product should be free of dirt. Under normal transportation and storage conditions, it should be guaranteed not to rust for half a year from the date of leaving the factory. 4.2 The product should be packed before leaving the factory. The packaging materials can be selected according to the specific conditions of the manufacturer. However, under normal transportation and storage conditions, the parts shall not be damaged or lost due to improper packaging. 4.3 The rubber sealing ring should be packed separately, and the rubber should not be polluted, damaged or opaque. During transportation, it is strictly forbidden to contact with corrosive and harmful substances to rubber, and avoid direct sunlight and rain. The rubber sealing ring should be stored in a cool, dry, ventilated place away from heat sources.
4.4 The packaging surface should be attached with a label, the content of which is as follows: Manufacturer name:
b. Product name and specifications:
Manufacturing date or production batch number:
d. Product quantity.
4.5 The product inspection certificate and instruction manual should be attached. A.1 Installation method
A.1.1 Welding
GB8259-87
Appendix A
Installation and use instructions of the card-type flexible pipe joint (reference part)
Before installing the joint, weld the end pipe to the end of the pipe. Before welding, check the sealing surface of the end pipe and deal with the collision, scratches, burrs and dirt that affect the sealing effect.
A.1.1.1 The end face of the steel pipe should be perpendicular to its axis. A.1.1.2 Before welding, the rust and paint on the steel pipe and the end pipe weld should be removed. A,1. 1. 3 During welding, the steel pipe and the end pipe should remain coaxial. A.1.1.4 The end pipe uses a single-sided V-groove single-sided continuous weld and steel pipe butt welding. The recommended welding rod brand is T422. The weld line must not have defects such as pores, slag inclusions, cracks and incomplete penetration.
A.1.1.5 To protect the sealing surface from the impact of welding spatter, the end pipe sealing surface should be covered with a protective cover before welding. A.1.1.6 Connect the steel pipe with welded end pipes with a clamp-type flexible pipe joint for water pressure test. The test pressure is 1.5 times the working pressure. The observation time is not less than 5 minutes. If there is no leakage, it is qualified. A.1.2 After the pressure test is qualified, except for the sealing surface, the steel pipe should be painted with anti-rust paint according to different requirements. A.1.3 In order to prevent the sealing surface from being damaged, the sealing surface should be covered with a protective cover during the transportation of the steel pipe. The protective cover can be purchased from the factory. A.1.4 Before assembly, the sundries in the steel pipe should be removed. Special attention should be paid to clean the sealing surface smoothly, without dirt and scratches. A.1.5 During assembly, the two steel pipes should be aligned with the axis, and the sealing surface, the inner cavity of the card, the joint surface of the two ears, and the threaded part of the bolts should be coated with No. 1 calcium-based grease (vaseline) or other grease that does not damage the rubber seal ring. Keep a certain distance between the two pipe ends according to the installation requirements, and then install and adjust the seal ring to a suitable position. Tighten the bolts so that the bolts on both sides are evenly hooked to prevent biting the seal ring. A.1.6 After the joint is installed, under any circumstances, its rotation angle should not exceed the values specified in GB8260-87 "Clamp-type flexible ring-type pipe joint" and GB8261-87 "Clamp-type flexible shoulder-type pipe joint". When the joint needs to have a rotation angle, it should be assembled according to the straight pipe first, and then the pipe should be folded to achieve the predetermined rotation angle. A.1.7 The single-side lip width of the rubber seal ring (see Figure 1) is selected according to Table A1. Table A1
50~175
200～600
700~1000
Additional Notes:
GB825987
This standard is under the jurisdiction of Xi'an Coal Mine Design Institute of the Ministry of Coal Industry. This standard was drafted by Xi'an Coal Mine Design Institute of the Ministry of Coal Industry, and the main drafters of this standard are Shi Xiaoxuan and An Zichou. From the date of implementation of this standard, the original departmental standard MT35-79G.JJ, GJH type pipe joints" will be invalid.4 Maximum pipe end gap inspection
GB8259-87
Figure 3 Principle diagram of the corner inspection device
The principle diagram of the maximum pipe end gap inspection device is shown in Figure 1. Head
Figure 4 Principle diagram of the maximum pipe end gap inspection device
External force
GB 8259-87
During the test, a head made of steel plate should be welded to both ends of the end pipe, and the pipe end gap should be 0, measured 1%, and then pressure water with low nominal pressure should be passed. After the end pipe moves, the maximum pipe end gap 4 (mm) is calculated according to formula (3): dL-
Where: L
The length measured when the pipe end gap is 0, mm, -The length measured when the pipe end gap reaches the maximum, mm. The value of the figure shall not be less than the maximum allowable pipe end gap. 3 Inspection rules
Ordering units can conduct random inspections on products delivered by manufacturers according to this standard to determine whether the batch of products delivered is qualified or not. 3.7
To determine acceptance or rejection, the inspection items shall be carried out in accordance with the requirements of Table 7 and 3.5. Technical requirements other than the inspection date listed in this standard shall be controlled by the manufacturer, or the ordering unit and the manufacturer shall discuss the inspection method. Table 7 Sampling plan table
Sampling plan
Pei Zhong, 1
Inspection items
Appearance and main
Dimension inspection
Corner expansion maximum section
End clearance inspection
Vacuum degree inspection
Leakage rate inspection
Seal and pressure
Strength inspection
Number of first random inspections;
Number of second random inspections.
A. The first qualified judgment number;
The first qualified judgment number,
The first unqualified judgment number;
The second unqualified judgment number.
Qualified quality level
Batch size
2150--500
150--500
150～500
>150~~500
Book size
m/n:
Judgment number
3.2 The factory inspection of the manufacturer can be carried out by the factory's quality inspection department according to the corresponding product technical requirements and the sampling method of this standard, and the product certificate will be issued for each qualified batch of products. 3.3 The manufacturer has the right to use other methods to conduct internal inspections, but the product quality must be guaranteed. 3.4 Sampling plan table
GB8259-87
The inspection work procedures of the sampling plan should comply with the provisions of GB2828-B1 "Batch inspection counting sampling procedures and sampling tables (applicable to the inspection of continuous batches)".
The batch range and corresponding sampling plan of each inspection item are shown in Table 7. Except for the joints on gas extraction or other negative pressure pipelines, which must be inspected for vacuum and gas leakage rate, other inspections are not required. 3.5 The inspection of fatal defects is a destructive inspection and should be carried out in accordance with Article 3.5 "Special provisions for fatal defects" in GB2828. 3.6 Explanation of sampling plan
3.6.1 The order of each inspection item should be carried out in the order specified in Table 7. Generally, the inspection of the next item should be carried out on the basis of the previous item being inspected and qualified.
3.6.2 If one of the items inspected is unqualified, the batch is unqualified. During the inspection process, if a certain indicator has been unqualified, there is no need to carry out the subsequent inspection items. 3.6.3 The orderer has the right to reject the unqualified products found during the inspection process, regardless of whether the product is part of the sample or whether the batch is judged to be accepted. Www.bzxZ.net
4 Packaging, storage and marking
4.1 The finished product should be free of dirt. Under normal transportation and storage conditions, it should be guaranteed not to rust for half a year from the date of leaving the factory. 4.2 The product should be packed before leaving the factory. The packaging materials can be selected according to the specific conditions of the manufacturer. However, under normal transportation and storage conditions, the parts shall not be damaged or lost due to improper packaging. 4.3 The rubber sealing ring should be packed separately, and the rubber should not be polluted, damaged or opaque. During transportation, it is strictly forbidden to contact with corrosive and harmful substances to rubber, and avoid direct sunlight and rain. The rubber sealing ring should be stored in a cool, dry, ventilated place away from heat sources.
4.4 The packaging surface should be attached with a label, the content of which is as follows: Manufacturer name:
b. Product name and specifications:
Manufacturing date or production batch number:
d. Product quantity.
4.5 The product inspection certificate and instruction manual should be attached. A.1 Installation method
A.1.1 Welding
GB8259-87
Appendix A
Installation and use instructions of the card-type flexible pipe joint (reference part)
Before installing the joint, weld the end pipe to the end of the pipe. Before welding, check the sealing surface of the end pipe and deal with the collision, scratches, burrs and dirt that affect the sealing effect.
A.1.1.1 The end face of the steel pipe should be perpendicular to its axis. A.1.1.2 Before welding, the rust and paint on the steel pipe and the end pipe weld should be removed. A,1. 1. 3 During welding, the steel pipe and the end pipe should remain coaxial. A.1.1.4 The end pipe uses a single-sided V-groove single-sided continuous weld and steel pipe butt welding. The recommended welding rod brand is T422. The weld line must not have defects such as pores, slag inclusions, cracks and incomplete penetration.
A.1.1.5 To protect the sealing surface from the impact of welding spatter, the end pipe sealing surface should be covered with a protective cover before welding. A.1.1.6 Connect the steel pipe with welded end pipes with a clamp-type flexible pipe joint for water pressure test. The test pressure is 1.5 times the working pressure. The observation time is not less than 5 minutes. If there is no leakage, it is qualified. A.1.2 After the pressure test is qualified, except for the sealing surface, the steel pipe should be painted with anti-rust paint according to different requirements. A.1.3 In order to prevent the sealing surface from being damaged, the sealing surface should be covered with a protective cover during the transportation of the steel pipe. The protective cover can be purchased from the factory. A.1.4 Before assembly, the sundries in the steel pipe should be removed. Special attention should be paid to clean the sealing surface smoothly, without dirt and scratches. A.1.5 During assembly, the two steel pipes should be aligned with the axis, and the sealing surface, the inner cavity of the card, the joint surface of the two ears, and the threaded part of the bolts should be coated with No. 1 calcium-based grease (vaseline) or other grease that does not damage the rubber seal ring. Keep a certain distance between the two pipe ends according to the installation requirements, and then install and adjust the seal ring to a suitable position. Tighten the bolts so that the bolts on both sides are evenly hooked to prevent biting the seal ring. A.1.6 After the joint is installed, under any circumstances, its rotation angle should not exceed the values specified in GB8260-87 "Clamp-type flexible ring-type pipe joint" and GB8261-87 "Clamp-type flexible shoulder-type pipe joint". When the joint needs to have a rotation angle, it should be assembled according to the straight pipe first, and then the pipe should be folded to achieve the predetermined rotation angle. A.1.7 The single-side lip width of the rubber seal ring (see Figure 1) is selected according to Table A1. Table A1
50~175
200～600
700~1000
Additional Notes:
GB825987
This standard is under the jurisdiction of Xi'an Coal Mine Design Institute of the Ministry of Coal Industry. This standard was drafted by Xi'an Coal Mine Design Institute of the Ministry of Coal Industry, and the main drafters of this standard are Shi Xiaoxuan and An Zichou. From the date of implementation of this standard, the original departmental standard MT35-79G.JJ, GJH type pipe joints" will be invalid.The first qualified judgment number;
The first qualified judgment number,
The first unqualified judgment number;
The second unqualified judgment number.
Qualified quality level
Order specification
2150--500
150--500
150～500
>150~~500
Original size
m/n:
Judgment number
3.2 The factory inspection of the manufacturer can be carried out by the factory's quality inspection department according to the corresponding product technical requirements and the sampling method of this standard, and the product certificate will be issued for each qualified batch of products. 3.3 The manufacturer has the right to use other methods to conduct internal inspections, but must ensure product quality. 3.4 Sampling plan table
GB8259-87
The inspection procedure of the sampling plan shall comply with the provisions of GB2828-B1 "Batch inspection counting sampling procedure and sampling table (applicable to the inspection of continuous batches)".
The batch range and corresponding sampling plan of each inspection item are shown in Table 7. Except for the joints on the gas extraction or other negative pressure pipelines, which must be inspected for vacuum and gas leakage rate, other inspections are not required. 3.5 The inspection of fatal defects is a destructive inspection and should be carried out in accordance with Article 3.5 "Special provisions for fatal defects" in GB2828. 3.6 Sampling plan description
3.6.1 The order of each inspection item shall be carried out in the order specified in Table 7. Generally, the inspection of the next item shall be carried out on the basis of the previous item being inspected and qualified.
3.6.2 If any item in the inspection item fails, the batch shall be deemed unqualified. During the inspection, if a certain indicator has failed, there is no need to conduct further inspection items. 3.6.3 The orderer has the right to reject the unqualified products found during the inspection, regardless of whether the product is part of the sample or whether the batch is judged to be accepted.
4 Packaging, storage and marking
4.1 The finished product should be free of dirt. Under normal transportation and storage conditions, it should be guaranteed not to rust for half a year from the date of leaving the factory. 4.2 The product should be packed before leaving the factory. The packaging material can be selected according to the specific conditions of the manufacturer. However, under normal transportation and storage conditions, parts shall not be damaged or lost due to improper packaging. 4.3 Rubber sealing rings should be packed separately, and the materials that do not pollute, damage or are opaque to rubber should be used for packaging. During transportation, it is strictly forbidden to contact with corrosive and harmful substances to rubber, and avoid direct sunlight and rain. Rubber sealing rings should be stored in a cool, dry, ventilated place away from heat sources.
4.4 The packaging surface shall be attached with a label, the contents of which are as follows: Manufacturer name:
b. Product name and specifications:
Date of manufacture or production batch number:
d. Product quantity.
4.5 The product inspection certificate and instruction manual shall be attached. A.1 Installation method
A.1.1 Welding
GB8259-87
Appendix A
Installation and use instructions for card-type flexible pipe joints (reference)
Before installing the joint, weld the end pipe to the end of the pipe. Before welding, check the sealing surface of the end pipe and deal with the impact, scratches, burrs and dirt that affect the sealing effect.
A.1.1.1 The end face of the steel pipe shall be perpendicular to its axis. A.1.1.2 Before welding, remove the rust and paint on the steel pipe and the weld of the end pipe. A.1.1.3 During welding, the steel pipe and the end pipe should be kept coaxial. A.1.1.4 The end pipe is welded with a single-sided V-groove single-sided continuous weld and the steel pipe. The recommended welding rod brand is T422. The weld line shall not have defects such as pores, slag inclusions, cracks and incomplete penetration.
A.1.1.5 In order to protect the sealing surface from the impact of welding spatter, the end pipe sealing surface should be covered with a protective cover before welding. A.1.1.6 The steel pipe with welded end pipes is connected with a clamp-type flexible pipe joint for water pressure test. The test pressure is 1.5 times the working pressure. The observation time is not less than 5 minutes. If there is no leakage, it is qualified. A.1.2 After the pressure test is qualified, except for the sealing surface, the steel pipe should be coated with anti-rust paint according to different requirements. A.1.3 In order to prevent the sealing surface from being damaged, the sealing surface should be covered with a protective cover during the transportation of the steel pipe. The protective cover can be purchased from the manufacturer. A.1.4 Before assembly, the sundries in the steel pipe should be removed. Special attention should be paid to clean the sealing surface smoothly, without dirt and scratches. A.1.5 During assembly, the two steel pipes should be aligned with the axis, and the sealing surface, the inner cavity of the card, the joint surface of the two ears, and the threaded part of the bolts should be coated with No. 1 calcium-based grease (vaseline) or other grease that does not damage the rubber seal ring. Keep a certain distance between the two pipe ends according to the installation requirements, and then install and adjust the seal ring to a suitable position. Tighten the bolts so that the bolts on both sides are evenly hooked to prevent biting the seal ring. A.1.6 After the joint is installed, under any circumstances, its rotation angle should not exceed the values specified in GB8260-87 "Clamp-type flexible ring-type pipe joint" and GB8261-87 "Clamp-type flexible shoulder-type pipe joint". When the joint needs to have a rotation angle, it should be assembled according to the straight pipe first, and then the pipe should be folded to achieve the predetermined rotation angle. A.1.7 The single-side lip width of the rubber seal ring (see Figure 1) is selected according to Table A1. Table A1
50~175
200～600
700~1000
Additional Notes:
GB825987
This standard is under the jurisdiction of Xi'an Coal Mine Design Institute of the Ministry of Coal Industry. This standard was drafted by Xi'an Coal Mine Design Institute of the Ministry of Coal Industry, and the main drafters of this standard are Shi Xiaoxuan and An Zichou. From the date of implementation of this standard, the original departmental standard MT35-79G.JJ, GJH type pipe joints" will be invalid.The first qualified judgment number;
The first qualified judgment number,
The first unqualified judgment number;
The second unqualified judgment number.
Qualified quality level
Order specification
2150--500
150--500
150～500
>150~~500
Original size
m/n:
Judgment number
3.2 The factory inspection of the manufacturer can be carried out by the factory's quality inspection department according to the corresponding product technical requirements and the sampling method of this standard, and the product certificate will be issued for each qualified batch of products. 3.3 The manufacturer has the right to use other methods to conduct internal inspections, but must ensure product quality. 3.4 Sampling plan table
GB8259-87
The inspection procedure of the sampling plan shall comply with the provisions of GB2828-B1 "Batch inspection counting sampling procedure and sampling table (applicable to the inspection of continuous batches)".
The batch range and corresponding sampling plan of each inspection item are shown in Table 7. Except for the joints on the gas extraction or other negative pressure pipelines, which must be inspected for vacuum and gas leakage rate, other inspections are not required. 3.5 The inspection of fatal defects is a destructive inspection and should be carried out in accordance with Article 3.5 "Special provisions for fatal defects" in GB2828. 3.6 Sampling plan description
3.6.1 The order of each inspection item shall be carried out in the order specified in Table 7. Generally, the inspection of the next item shall be carried out on the basis of the previous item being inspected and qualified.
3.6.2 If any item in the inspection item fails, the batch shall be deemed unqualified. During the inspection, if a certain indicator has failed, there is no need to conduct further inspection items. 3.6.3 The orderer has the right to reject the unqualified products found during the inspection, regardless of whether the product is part of the sample or whether the batch is judged to be accepted.
4 Packaging, storage and marking
4.1 The finished product should be free of dirt. Under normal transportation and storage conditions, it should be guaranteed not to rust for half a year from the date of leaving the factory. 4.2 The product should be packed before leaving the factory. The packaging material can be selected according to the specific conditions of the manufacturer. However, under normal transportation and storage conditions, parts shall not be damaged or lost due to improper packaging. 4.3 Rubber sealing rings should be packed separately, and the materials that do not pollute, damage or are opaque to rubber should be used for packaging. During transportation, it is strictly forbidden to contact with corrosive and harmful substances to rubber, and avoid direct sunlight and rain. Rubber sealing rings should be stored in a cool, dry, ventilated place away from heat sources.
4.4 The packaging surface shall be attached with a label, the contents of which are as follows: Manufacturer name:
b. Product name and specifications:
Date of manufacture or production batch number:
d. Product quantity.
4.5 The product inspection certificate and instruction manual shall be attached. A.1 Installation method
A.1.1 Welding
GB8259-87
Appendix A
Installation and use instructions for card-type flexible pipe joints (reference)
Before installing the joint, weld the end pipe to the end of the pipe. Before welding, check the sealing surface of the end pipe and deal with the impact, scratches, burrs and dirt that affect the sealing effect.
A.1.1.1 The end face of the steel pipe shall be perpendicular to its axis. A.1.1.2 Before welding, remove the rust and paint on the steel pipe and the weld of the end pipe. A.1.1.3 During welding, the steel pipe and the end pipe should be kept coaxial. A.1.1.4 The end pipe is welded with a single-sided V-groove single-sided continuous weld and the steel pipe. The recommended welding rod brand is T422. The weld line shall not have defects such as pores, slag inclusions, cracks and incomplete penetration.
A.1.1.5 In order to protect the sealing surface from the impact of welding spatter, the end pipe sealing surface shou
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