SY 0402-2000 Specification for construction and acceptance of process pipeline engineering in petroleum and natural gas stations
Some standard content:
1 General Provisions
Petroleum and Natural Gas Industry Standard of the People's Republic of China
Construction and Acceptance Specifications for Process Pipeline Engineering in Petroleum and Natural Gas Stations
Approval Department: State Administration of Petroleum and Chemical Industry Approval Date: 2000-03-31
Implementation Date: 2000-10-01
SY 0402--2000
Replacement: SYJ4002--1990
SYJ4023-1989
SY/T4067-1993
1.0.1 In order to improve the construction level of petroleum and natural gas process pipeline engineering, ensure the quality of production and installation, and achieve advanced technology, economic rationality, safety and reliability, this specification is specially formulated.
1.0.2 This specification is applicable to the process pipeline engineering in the station related to the new construction or modification (expansion) of petroleum and natural gas gathering and transportation process. 1.0.3 This specification is not applicable to: dehydration devices inside oil and gas fields; pipelines inside refineries and natural gas purification plants; process pipelines at gas stations, pipelines belonging to pumps, heating furnaces, flow meters and other similar equipment in stations; high-temperature heat transfer oil pipelines in stations. 1.0.4 The requirements for industrial health, safety, environmental protection and other aspects involved in the construction of process pipelines shall also comply with the relevant mandatory standards and regulations of the state and local governments on industrial health, safety, environmental protection and other aspects. 1.0.5 The construction enterprises responsible for the process pipelines in oil and gas stations must have undertaken petroleum engineering construction and obtained the corresponding qualification certificates of construction enterprises; establish a quality assurance system to ensure the quality of engineering installation. 1.0.6 In addition to complying with this specification, the construction and acceptance of process pipelines shall also comply with the provisions of the relevant mandatory standards currently in force in the country. 2 Inspection of pipeline components
2.1 General provisions
2.1.1 All pipeline components shall be checked for their specifications, materials and models according to design requirements before use. 2.1.2 Pipeline components must have product quality certificates, factory certificates and instructions. If there is any doubt about the quality, it must be re-inspected according to the supply contract and product standards, and its performance indicators should comply with the relevant provisions of the current national or industry standards. 2.1.3 The appearance of the pipeline components should be inspected before use, and their surface quality should comply with the relevant provisions of the design or manufacturing standards. 2.2 Pipes
2.2.1 Pipes with special requirements should be ordered according to the design requirements and inspected according to their requirements. 2.3 Pipe fittings, fasteners
2.3.1 The dimensional deviation of elbows, reducers, tees, flanges, gaskets, blind plates, compensators and fasteners, etc., should comply with the relevant provisions of the current national or industry standards.
2.3.2 Before using pipe fittings and fasteners, check the quality certificate of their manufacturers and confirm that the following items meet the relevant provisions of national or industry technical standards:
1 Chemical composition;
2 Mechanical properties after heat treatment:
3 Metallographic analysis report of alloy steel pipe fittings,
4 Nondestructive testing report of pipe fittings and fasteners. The technical requirements of high-pressure pipe fittings and fasteners shall comply with the relevant provisions of "PN16.0~32.0MPa Forged Angle High-Pressure Valves, Pipe Fittings, Fasteners Technical 2.3.3
Conditions" JB450.
2.3.4 The quality of flanges shall meet the following requirements: 1 The flange sealing surface shall be smooth and flat, without burrs, scratches, radial grooves, sand eyes and pores. 2 There shall be no bumps on the tail groove of the butt-welded flange. 3 The threads of the threaded flange shall be intact without broken wires. SY0402—2000
4 The allowable deviation of the center circle diameter of the flange bolt is ±0.3mm; the allowable deviation of the flange thickness is ±1.0mm; the allowable deviation of the center distance between two adjacent bolt holes is ±0.3mm, and the allowable deviation of the center distance between any two holes is ±1.0mm. 2.3.5 Pipe fittings and fasteners used in acidic environments should be processed according to design requirements and can only be used after passing the test. 2.3.6 Flange connector bolts, nuts, spiral wound gaskets, etc. should meet the assembly requirements and should not have defects such as scratches, burrs, warping and broken wires that affect assembly.
2.3.7 Bolts and nuts used on high-pressure pipelines should comply with the provisions of the current relevant national standards. Before use, two (pieces) should be taken from each batch for hardness inspection. If unqualified, double inspection should be carried out; if there are still unqualified ones, check them one by one, and unqualified ones shall not be used. When the diameter is greater than or equal to M30 and the working temperature is greater than or equal to 500℃, the hardness should be checked one by one. If the nut hardness is unqualified, it cannot be used; if the bolt hardness is unqualified, take the highest and lowest one to check the mechanical properties. If there is an unqualified one, take the bolts with similar hardness to double check. If there is still an unqualified one, the batch of bolts shall not be used.
2.3.8 The inspection and quality of the tee shall meet the following requirements: The main pipe shall be opened according to the actual inner diameter of the branch pipe, the hole wall shall be flat and smooth, and the allowable deviation of the hole diameter shall be ±0.5mm. 2 The opening of the main pipe and the bevel of the branch pipe shall be clean, free of dirt, oil stains and rust spots. 3
The bevel angle of the end face of the tee shall be 35°±5°, and the blunt edge shall be 1.0~~2.0mm. The allowable deviation of the verticality of the branch pipe and the main pipe shall not be greater than 1% of the height of the branch pipe, and shall not be greater than 3mm. The allowable deviation of the verticality of each end face shall not be greater than 1% of the outer diameter of the steel pipe, and shall not be greater than 3mm. The appearance quality of the reinforcement plate weld should meet the design requirements. 6
The inspection of the drawn tee should be carried out according to the design requirements, and its wall thickness, thinning amount, etc. must meet the requirements. The inspection and quality of the elbow should meet the following requirements: The appearance of the elbow shall not have defects such as cracks, delamination, wrinkles, overburning, etc. The wall thickness thinning of the elbow should be less than 10% of the thickness, and the measured thickness shall not be less than the designed calculated wall thickness. The bevel angle of the elbow should be 35±5°, and the blunt edge should be 1.0~2mm. 3
4 The end face deviation, bending angle deviation, roundness, and curvature radius deviation of the elbow shall meet the requirements of Table 2.3.9. Table 2.3.9 Permissible deviation of pipe bending
Inspection items
End face deviation
Deviation of curvature radius
Deviation of bending angle
Deviation of roundness
Nominal diameter
80~100
125~200
≤1% of nominal diameter
2.3.10 Inspection and quality requirements of pipe bends shall meet the following requirements: 1 The inner and outer surfaces of the pipe bends shall be smooth, without defects such as cracks, scars, wrinkles, bulges, etc. 2 The dimensional deviation of the pipe bends shall meet the requirements of Table 2.3.10. ≥250
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3 The diameter of the pipe bend shall be consistent with the inner diameter of the connected pipe. Table 2.3.10 Inspection items for allowable deviations of casing and reducers
Outer diameter deviation (seamless)
Outer circumference deviation (seamless)
Wall thickness reduction
Length deviation (bend refers to radius)
End face inclination
25-~70
80~100
Nominal diameter
125200
250~~400
Medium pressure ≤12.5% wall thickness, high pressure ≤10% wall thickness ≤2.0
≤1% of nominal diameterbzxZ.net
2.3.11 The inspection and quality requirements of reducers shall comply with the following provisions: 1 The wall thickness of the reducer shall be greater than the wall thickness of the large diameter end pipe section. 600
2 The roundness of the reducer shall not be greater than 1% of the outer diameter of the corresponding end, and shall not be greater than 3mm; the center lines of the two ends shall coincide, and the eccentricity value shall not be greater than 5 mm.
3 The allowable deviation of the reducer size shall comply with the provisions of Table 2.3.10. 4 The eccentric reducer shall be inspected according to the design requirements. 2.3.12 The inspection and quality requirements of the hanger shall comply with the following provisions: 1 The surface of the hanger shall be free of defects such as burrs, rust, cracks, welding leaks, surface pores, etc. 2 The surface of the spring used for the hanger shall not have defects such as cracks, folds, delamination, rust, etc., and the deviation of the number of working turns shall not exceed half a turn. 3 In the free state, the pitch of each spring turn is uniform, and the allowable deviation of the pitch shall not be greater than 10% of the average pitch. The support surfaces at both ends of the spring shall be perpendicular to the spring axis, and the allowable deviation shall not be greater than 2% of the free height. 4
2.3.13 Inspection of pipeline compensators shall be carried out in accordance with the factory instructions and design requirements, and the dimensional deviation shall meet the following requirements: 1 The roundness of the curved tube of "Ⅱ\" and "" type compensators shall not be greater than 8% of the outer diameter, the wall thickness reduction shall not be greater than 15% of the nominal wall thickness, and the wall thickness shall not be less than the designed wall thickness. 2 The allowable deviation of the cantilever length of "Ⅱ\" type compensators is ±10mm; the allowable deviation of plane warpage per meter shall not be greater than 3mm, and the total length plane warpage shall not be greater than 10mm.
2.4 Valves
2.4.1 Valves shall have product certificates, and electric, pneumatic, hydraulic, airflow linkage, gas-hydraulic, electro-hydraulic, electromagnetic-hydraulic, electromagnetic-actuated and other valves shall have installation and use instructions.
The appearance of the valve shall be inspected before testing, and its appearance quality shall meet the following requirements: 2.4.2
The valve body, valve cover and valve outer surface shall be free of defects such as pores, sand holes and cracks. The inner surface of the valve body shall be smooth and clean, and the gate, spherical surface and its mating surface shall be free of scratches, depressions and other defects. 2
The gasket and filler shall meet the medium requirements and be installed correctly. 4
The bolts, connecting flanges, internal and external threads shall meet the technical requirements. The screw rod, hand wheel and handle shall be free of burrs and scratches, and the transmission mechanism shall be flexible to operate, indicate correctly and be fully in place. 5
6 Other valves (electric, pneumatic, etc.) and various parts shall be complete and intact without looseness. 376
7 The nameplate shall be intact and the markings shall be complete and correct. 2.4.3 The strength and sealing tests of the valve shall comply with the following provisions: 1 The accuracy of the pressure gauge used for pressure test shall not be lower than Class 1.5 and shall be qualified after verification. SY 0402-—2000
2 The inspection scope of valves shall be: valves with nominal diameter less than or equal to 50mm and nominal pressure less than or equal to 1.6MPa, 10% of each batch shall be randomly inspected, and no less than 1; if there are unqualified ones, another 20% shall be randomly inspected; if there are still unqualified ones, the batch of valves shall be inspected and tested one by one. Valves with nominal diameter greater than 50mm or nominal pressure greater than 1.6MPa shall be inspected. 3 Valves shall be subjected to strength and sealing tests with clean water. The strength test pressure shall be 1.5 times of the working pressure, and the pressure shall be stabilized for not less than 5min. The shell, gasket, packing, etc. shall not leak, deform, or be damaged, and the pressure gauge shall not drop to be qualified. The sealing test pressure is the working pressure, and the pressure shall be stabilized for 15min. If there is no internal leakage and the pressure gauge does not drop to be qualified. 4 When the valve is subjected to strength pressure test, the valve shall be half-open and half-closed, and water shall be allowed to enter the middle cavity for overall pressure test. During the sealing pressure test, the valve shall be opened under pressure on one side. Manual valves should be opened under single-sided pressure, and the flexibility of the hand wheel and the leakage of the packing should be checked; electric valves should be adjusted as required. After the limit switch is tested and operated, they should be opened under single-sided pressure under the sealing test. Both sides of the valve should be opened under single-sided pressure, and the opening pressure should be greater than or equal to the working pressure. Unqualified valves shall not be used. 5 Check valves and stop valves can be tested for strength and sealing according to the flow direction. Check valves should be tested for sealing in the reverse direction and strength in the downstream direction. Stop valves can be tested for strength and sealing in the downstream direction. 6 After the valve pressure test is qualified, the internal water (including the middle cavity) should be removed, the sealing surface should be coated with a protective layer, the valve should be closed, the main inlet should be sealed, and the "Valve Pressure Test Record" should be filled in.
2.4.4 The safety valve should be pressure debugged before installation, and its opening pressure should be 1.05 to 1.15 times the working pressure. The return seat pressure should be between 0.90 and 1.05 times the working pressure, and the debugging should be no less than 3 times. After qualified debugging, seal it and fill in the record. 2.4.5 The hydraulic ball valve drive device should be checked according to the factory manual. The pressure oil should be at 2/3 of the oil mark, and each part should be flexible. 2.4.6 Check the transmission device of the electric valve and the sealing and lubrication parts of the motor to make the transmission and electrical parts flexible and easy to use, and debug the limit switch.
3 Steel pipe cutting and pipe fitting processing
3.1 Steel pipe cutting
3.1.1 Steel pipes used under high pressure conditions should be cut mechanically, and medium and low pressure steel pipes can be cut by oxyacetylene. After cutting, the oxide layer on the cut surface must be removed, the solitary ripples of the cut must be eliminated, and the groove must be processed as required. 3.1.2 The quality of the steel pipe cut should meet the following requirements: 1 The cut surface should be flat, without cracks, heavy skin, burrs, bumps, shrinkage, slag, oxides, iron filings, etc. 2 The inclination deviation of the cut end face △ (Figure 3.1.2) should not be greater than 1% of the outer diameter of the pipe and should not exceed 3mm. 14
Figure 3.1.2 Inclination deviation of the cut end face
3.1.3 The steel pipe should be straightened before use due to the bending caused by transportation and stacking. Its straightness should not exceed 1.5mm per meter and the total length should not exceed 5mm.
3.1.4 The groove type and assembly size of the pipe end should meet the requirements of Table 3.1.4. 377
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Butt connection between pipes and fittings
Butt connection between pipes
Butt connection between pipes with different wall surfaces
Branch pipe of tee joint
Main pipe of tee joint with socket
3.2 Processing of pipe fittings
End form
1.≥4(82-6)
Type of groove at pipe end and assembly size
Wall thickness 8
3.2.1 When pipes are butt connected, the amount of misalignment shall comply with the provisions of Table 3.2.1. 378
Groove size
Angle α
70°±5°
60°±5°
70°±5°
60°±5°
70°±5°
60°±5
50°±5°
50°±5
Blunt edge force
Upward welding 1～2.0
Downward welding 1～~1 .5
Upward welding 1~2.0
Downward welding 1~～1.5
Upward welding 1～2.0
Downward welding 1～1.5
Upward welding 1~2.0
Downward welding 1～1.5
Upward welding 1～2.0
Downward welding 1～1.5
Upward welding 1～2.0
Downward welding 1~～1.5
1. 0 ~ 1. 5
Gap b
Upward welding 1~2.5
Downward welding 1~2.0
Upward welding 1~3.5
Downward welding 12.0
Upward welding 1~2.5
Downward welding 1~2.0
Upward welding 1~3.5
Downward welding 1~2.0
Upward welding 1~~2. 5
Downward welding 1~2.0
Upward welding 1~3.5
Downward welding 1~2.0
1. 5~2. 5
1. 5~2. 5
Pipe wall thickness
3.2.2 The production of bent pipes shall comply with the following provisions: Table 3.2.1 Misalignment of the bend
Misalignment of the inner wall
0.1 Wall thickness
SY 0402--2000
Misalignment of the outer wall
1 Bends should be made of pipes with positive wall thickness tolerance. When pipes with negative tolerance are used to make bends, the relationship between the bending radius of the pipe and the wall thickness of the pipe before bending should comply with the provisions of Table 3.2.2. Table 3. 2. 2 Relationship between the bending radius and the wall thickness of the pipe before bending Bending radius R
R≥6DN
6DN>R≥5DN
Note: ①DN is the nominal diameter (mm);
②T is the designed wall thickness (mm).
Pipe wall thickness before bending
Bending radius R
5DN>R≥4DN
4DN>R≥3DN
Pipe wall thickness before bending
2The bending radius of high-pressure steel pipes should be greater than 5 times the outer diameter of the pipe, and the bending radius of other pipes should be greater than 3.5 times the outer diameter of the pipe. 3When making bends with seamed pipes, the welds should avoid the tension (compression) area. 4Steel pipes should be cold or hot bent within the range allowed by their material properties. 5When making bends with high-alloy steel pipes, mechanical methods should be used; when making bends with sand, hammers should not be used. 3.2.3 The heat treatment after hot bending or cold bending of steel pipes shall comply with the following provisions: Except for the case where the temperature of the bend is maintained above 900℃ from beginning to end, after the bend is made of carbon steel with a wall thickness greater than 19mm1
, it shall be heat treated according to the provisions of Table 3.2.3. 2 When the medium and low alloy steel pipes listed in Table 3.2.3 are used for hot bending, for those with a nominal diameter greater than or equal to 100mm, or a wall thickness greater than or equal to 13mtm, full annealing, normalizing and tempering or tempering treatment shall be carried out according to the requirements of the design documents. 3 When the medium and low alloy steel pipes listed in Table 3.2.3 are used for cold bending, for those with a nominal diameter greater than or equal to 100mm, or a wall thickness greater than or equal to 13mm, heat treatment shall be carried out according to the requirements of Table 3.2.3. 4 Bends made of austenitic stainless steel pipes do not need to be heat treated. When the design documents require heat treatment, it shall be carried out according to the provisions of the design documents.
3.2.4 The quality of the bent pipe shall meet the following requirements: 1. No cracks (visual inspection or according to the design documents). 2. No defects such as overburning and delamination.
3. No wrinkles.
4 For bent pipes with a design pressure greater than or equal to 10MPa, the difference between the maximum outer diameter and the minimum outer diameter on any section shall not be greater than 5% of the outer diameter of the pipe before the bend; the difference in wall thickness before and after the bend shall not exceed 10% of the wall thickness before the bend; the center deviation value of the pipe end shall not exceed 1.5mm/m, when the straight pipe length L is greater than 3m, the deviation shall not exceed 5mm. 5 For bends with a design pressure less than 10MPa, the difference between the maximum outer diameter and the minimum outer diameter on any section shall not be greater than 8% of the outer diameter of the pipe before the bend.
6 For other bends, the difference in pipe wall thickness before and after the bend shall not exceed 15% of the pipe wall thickness before the bend, and shall not be less than the design wall thickness of the pipe; the center deviation of the pipe end shall not exceed 3mm/m, when the straight pipe length is greater than 3m, the deviation shall not exceed 10mm.
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Pipe material category
Carbon steel
Medium and low alloy steel
Nominal composition
c-Mn-V
C-Cr-Mo
C-Cr-Mo-V
Note: T is the pipe wall thickness (mm).
Pipe grades
10,15,
12CrMo
15CrMo
12Cr2Mo
5Cr1Mo
9CrlMo
12Cr1MoV
Table 3.2.3 Commonly used pipe heat treatment conditions
Heat treatment temperature (℃)
60~650
600~650
600～700
600 ~700
600-~650
600650
700~750
700~760
700~760
700-~760
700～760
600650
600～630
Heating rate
When the heating temperature rises
to 400℃, the heating rate should not be greater than
205× 25/T
(℃ /h)
Constant temperature time
The constant temperature time should be
1 h for every 25mm wall thickness, and shall not be less than
15 min. During the constant temperature period, the maximum and minimum temperature difference should be lower than 65℃. 3.2.5 The allowable deviation △ of the flatness of II-shaped elbow should comply with the requirements of Table 3.2.5 and Figure 3.2.5. Required center
Actual center
Bending angle and tube end center deviation
5I Flatness allowable deviation of deformed tube
Flatness△
500～1000
Figure 3.2.5 Flatness of II-shaped bend
>1000～1500
Cooling speed
The cooling speed after constant temperature
should not exceed 260×
25/T(℃/h), and shall not be greater than 260℃/h.
It can be naturally cooled below 400℃
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3.2.6 After making elbows with high-pressure steel pipes, non-destructive testing of the surface should be carried out. If heat treatment is required, it should be carried out after heat treatment; if there are defects, grinding can be carried out. The wall thickness of the elbow after grinding shall not be less than 90% of the nominal wall thickness of the pipe, and shall not be less than the designed wall thickness. 3.2.7 The processing of coiling, flanging of pipe mouths, processing of jacketed pipes and their quality shall comply with the provisions of GB50235, Code for Construction and Acceptance of Industrial Metal Pipeline Engineering.
The production and quality of manifolds shall comply with the following provisions. 3.2.8
1 It is advisable to select a whole seamless steel pipe for making the mother pipe of the manifold. If welded steel pipes are used for butt joint, the longitudinal seams or spiral welds should be staggered by more than 100mm. For spiral welded steel pipes, reinforcement welding should also be carried out at the spiral welds at the pipe ends, and the length should not be less than 20mm. 2 The marking of the main pipe of the manifold shall comply with the following provisions: 1)
Mark the center line of the fixed main pipe;
Mark the opening center and opening line according to the spacing required by the drawing. 3
When the manifold adopts the riding seat connection, the opening diameter of the main pipe shall be 2mm smaller than the inner diameter of the branch pipe. The bevel and corner joints of the sub-pipe shall comply with the provisions of Table 3.2.8-1 and Figure 3.2.8. Table 3.2.8-1 Dimensions of sub-pipe groove and corner joints
Angle β between sub-pipe and saddle
Groove angle α
Joint angle Φ
90°~105°
45°~60°
105°～150°
45°~90°
Root gap b (mm)
Blunt edge p (mm)
4When the manifold adopts plug-in connection, a hole should be opened on the mother pipe and the groove should be processed. The groove angle should be 45~60°, and the allowable deviation should be ±2.5°. The gap between the hole and the outer diameter of the sub-pipe is 0.5~2 mm. The insertion depth of the sub-pipe shall not exceed the inner wall of the mother pipe. 5When the manifold is assembled, the sub-pipe and flange should be assembled first. When the mother pipe and the daughter pipe are assembled, the two end daughter pipes should be assembled first so that they are parallel to each other and perpendicular to the mother pipe, and then the middle daughter pipes should be assembled based on the two daughter pipes.
6 When the manifold is assembled, when the nominal diameter of the daughter pipe is less than or equal to 200mm, 4 points of positioning welding are performed; when the nominal diameter of the daughter pipe is greater than 200mm, 6 points of positioning welding are performed and evenly distributed. 7 The allowable deviation of the manifold assembly shall comply with the provisions of Table 3.2.8-2. 8 Before the head is assembled, the inside of the manifold should be cleaned, and the assembly welding should comply with the requirements of the design drawings. 9 The welding quality of the manifold shall comply with the provisions of Chapter 5 of this specification. Table 3.2.8-2 Allowable deviation of assembly
Note: 1. It is the length of the mother pipe (m).
Flange horizontality or
verticality
Pipe holding straightness
Total length of mother pipe
Sub-pipe spacing
Relative offset between the center lines of sub-pipe and mother pipeSub-pipe flange connection length
Sub-pipe diameter
Nominal diameter of mother pipe
Joint angle Φ
90°～105°
1. 5~~2. 5
105°~150°
1. 5 ~ 2. 5
Figure 3.2.8 Sub-pipe groove angle
Allowable deviation (mm)
≤L/1000, maximum 15
≤2L/1000, maximum 15
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4 Pipeline Installation
4. General Provisions
4.1.1 Before pipeline installation, the process pipeline construction drawings must be reviewed by civil engineering, electrical engineering, instrumentation, water supply and drainage and other related professionals, especially the buried pipelines and buried cables, water supply and drainage pipelines, underground facilities, and the reserved holes of buildings. 4.1.2 The civil engineering projects related to pipeline installation shall be inspected and accepted and meet the installation conditions. 4.1.3 The pipes, pipe fittings, valves and other prefabricated parts used in the process pipelines shall be inspected and qualified in accordance with the provisions of this specification. 4.1.4 The equipment, pipe racks and pipe piers connected to the pipelines shall be aligned. After installation and fixing, the slope and slope of the pipe racks and pipe piers shall meet the design requirements.
4.1.5 The inside of the pipes, pipe fittings, valves, etc. shall be cleaned and free of dirt and debris. When the installation work is interrupted, the pipe or valve outlet shall be blocked in time.
4.1.6 After the buried pipeline is inspected and welded, it shall be tested for pressure, anti-corrosion and backfilled in time. Before backfilling, the hidden project inspection and acceptance procedures shall be handled.
4.1.7 It is not advisable to make holes at the position of the pipeline weld and its edge. When it is unavoidable, the opening shall be reinforced within 1.5 times the diameter of the hole, and the weld covered by the reinforcement plate shall be ground flat. The inspection of weld quality shall comply with the provisions of 5.4. 4.2 Pipeline installation
4.2.1 Prefabricated pipelines shall be installed according to the pipeline system number and sequence number. 4.2.2 When connecting pipelines, pipe fittings, valves, equipment, etc., strong force shall not be used. 4.2.3 Before installation, the following checks shall be made on the matching of valves, flanges and pipelines: 1 When welding the welding flange and the pipe, check whether their inner diameters are consistent. If not, open the inner groove as required. 2 Check the matching of the flat welding flange and the pipe. 3 Check the fit between the flange and the valve flange and the length of the connector to prevent mismatch during installation. 4.2.4 Check whether the inner diameter of the tee and elbow is consistent with the diameter of the pipe to which it is connected. If not, add an inner bevel as required. 4.2.5 The diameter of the reducer should be consistent with the connecting pipe section to which it is connected, and the misalignment of the fit should not be greater than 1.5mm. 4.2.6 When installing the pipeline, a butt welder should be used for butt welding. When using an external butt welder, the butt welder can only be removed when the root weld is completed for more than 50% of the circumference of the pipeline and evenly distributed; when using an internal butt welder, the root welder can only be removed after all the welds are completed. 4.2.7 When the roundness of the pipe port exceeds the standard, it should be calibrated. When calibrating the roundness, it is advisable to use a shaper for adjustment, and it is not advisable to use a hammer for adjustment. 4.2.8 When the pipes are butt-jointed, the straightness should be checked. According to Figure 4.2.8, the measurement should be made at a distance of 200mm from the center of the interface. When the nominal diameter of the pipe is less than 100mm, the allowable deviation is 1mm; when the nominal diameter of the pipe is greater than or equal to 100mm, the allowable deviation is 2mm, but the allowable deviation of the entire length is 10mm.
Steel Ruler
Figure 4.2.8 Pipeline Butt Straightness Check
4.2.9 When spiral welded steel pipes are butt-jointed, the spiral welds should be staggered by more than 100mm. 4.2.10 When steel pipes pass through buildings (structures), protective pipes should be added. The center line of the protective pipe should be consistent with the center line of the pipeline, and there should be no butt welds in the hidden places of the building (structure).
4.2.11 The allowable deviation value of pipeline installation shall comply with the provisions of Table 4.2.11. 382
Table 4.2.11 Allowable deviation of pipeline installation
Allowable deviation (mm)
Straightness
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Allowable deviation (mm)
DN≤100 mm|
≤2L/1000
DN>100mm≤3L/1000
Verticality
Spacing on the same plane
Spacing between outer wall of pipe or insulation layer
Maximum 40
Maximum 70
≤3H/1000
Maximum 25
4.2.12 For pipelines connected to machines, their fixed welds should be away from the machines. For machines that are not allowed to bear additional external forces, the connection between the pipeline and the machine shall comply with the following provisions:
1 When the pipeline is in a free state, check the parallelism and concentricity of the flange, and the allowable deviation shall comply with the provisions of Table 4.2.12. Table 4.2.12 Allowable deviation of flange parallelism, concentricity and equipment displacement Machine pump speed (r/min)
3000～6000
Parallelism (mm)
Concentricity (mm)
Equipment displacement (mm)
2 When tightening the bolts, the equipment displacement shall be observed on the main shaft section of the equipment with a dial indicator, and its value shall comply with the provisions of Table 4.2.12. 4.2.13 Before installing the pipeline compensator, it shall be pre-stretched (pre-compressed) according to the design requirements, and its allowable deviation is ±10mm. 4.2.14 The types and specifications of the brackets, supports, hangers and pipe clamps of the overhead pipeline shall be selected according to the design, the installation position shall comply with the design requirements, and the installation method shall be correct. The sliding bracket should ensure smooth axial sliding and no lateral deviation; the fixed bracket should be firmly installed. 4.2.15 The flange sealing surface should be perpendicular to the center of the pipe (Figure 4.2.15). When the nominal diameter is less than or equal to 300mm, the allowable deviation e on the flange outer diameter is ±1mm; when the nominal diameter is greater than 300mm, the allowable deviation e on the flange outer diameter is ±2mm. 4.2.16 The flange screw hole should be installed in the middle. When there are flanges at both ends of the pipeline, after welding one end flange to the pipeline, use a level ruler to level it, and the other end is also leveled. The flatness of the flat hole should be less than 1 mm.
4.2.17 The distance between the pipe end and the flat welding flange sealing surface should be the pipe wall thickness plus 2~~3mm. 4.2.18 The flanges should be kept parallel when connected, and the deviation should not be greater than 1.5/1000 of the flange outer diameter, and not greater than 2mm. The gasket should be placed in the center of the flange sealing surface and should not be tilted or protruding into the pipe. For flanges with ladder grooves or concave and convex sealing surfaces, the gaskets should be placed inside the grooves. 4.2.19 Each pair of flange connections should use bolts of the same specification and have the same installation direction. Bolt tightening should be carried out in a symmetrical order. All bolts should be tightened, the force should be uniform, and no bolts should be missed. Figure 4.2.15 Deviation of prefabricated pipe sections
4.2.20 After the flange bolts are tightened, the two sealing surfaces should be parallel to each other. Check symmetrically with a ruler, and the allowable deviation of the gap should be less than 0.5mm. 4.2.21 The flange connection should be coaxial with the pipeline, and the center deviation of the bolt hole should not exceed 5% of the aperture, and the bolts should be allowed to penetrate freely. After the flange bolts are tightened, 2 to 3 teeth should be exposed outside the nut. If the thread does not meet the requirements, it should be adjusted. 4.2.22 When the threaded flange is screwed into the threaded short section, the thread chamfer should be exposed, and the metal gasket should be accurately embedded in the sealing seat. 4.3 Valve Installation
4.3.1 Before installing the valve, check the valve packing and leave margin for adjustment for the gland bolts. 4.3.2 Before installing the valve, check the model according to the design documents, determine the installation direction according to the flow direction of the medium, and review the product certificate and test records.
SY 0402--2000
4.3.3 When the valve is connected to the pipeline by flange or thread, the valve should be installed in the closed state. 4.3.4 When the valve is connected to the pipeline by welding, the valve shall not be closed and the weld shall be of guaranteed quality. 4.3.5 When installing the valve, determine the installation direction of the valve according to the flow direction of the medium and avoid strong installation. When installing a double-disc gate valve on a horizontal pipe section, the handwheel should be upward. Under normal circumstances, the handwheel or handle of the valve after installation shall not be downward, and it should be installed in a position that is convenient for operation and maintenance according to the valve characteristics and the flow direction of the medium.
4.3.6 The installation of the safety valve shall comply with the following provisions: 1 Check the verticality and make corrections if any inclination is found. 2 The final adjustment of the safety valve should be carried out on the system, and the opening and return pressures should comply with the relevant provisions of the design documents and this specification. 5 Welding
5.1 General provisions
5.1.1 The welding of station steel pipelines shall be carried out in accordance with the relevant provisions of this chapter and the current industry standard "Welding and Acceptance of Steel Pipelines" SY/T4103.
5.1.2 In pipeline welding production, welding process tests and assessments shall be carried out for any steel type, welding materials and welding methods used for the first time. The welding process tests and assessments shall comply with the provisions of Chapter 5 of "Welding and Acceptance of Steel Pipelines" SY/T4103-1995. 5.1.3 When the existing welding process assessment results of the installation unit are used in new projects, further confirmation is required. When any of the elements does not conform to the actual situation, determine whether to re-evaluate the welding process according to the requirements of the welding process qualification regulations in this specification. 5.1.4 Prepare the welding process regulations based on the qualified welding process qualification report. 5.1.5 The personnel participating in the welding operation must be qualified welders who have obtained the corresponding qualifications through examinations in accordance with the welding process regulations. The welder qualification examination shall be carried out in accordance with the provisions of Chapter 6 of "Steel Pipeline Welding and Acceptance" SY/T4103-1995. 5.2 Welding
5.2.1 Before welding, the welding materials shall meet the following requirements: 1 The welding rod shall not be damaged, discolored, or have oily dirt; the welding wire shall not be rusted or contaminated, the flux shall not be deteriorated, and the purity and dryness of the shielding gas shall meet the requirements of the welding process regulations. 2 The welding rod shall be dried according to the product manual before use. When there is no requirement, the drying temperature of low hydrogen type welding rod is 350～400℃, and the constant temperature time is 1～2h. A constant temperature drying box (simple) should be set up at the welding site, and the temperature should be controlled at 100～150℃, and it can be taken out as needed. The welding rods that are not used up on the same day should be collected and used after re-drying, but the number of re-drying shall not exceed twice. Cellulose welding rods do not need to be dried when they are well packaged and not damp. If damp, they should be dried at a temperature of 80~~100℃ and a drying time of 0.5～1h. 3 If the welding rod coating falls off, turns red or has serious arc deviation during welding, it should be replaced immediately. 5.2.2 Welding operations shall not be carried out in the following unfavorable environments without effective protective measures: 1 Rainy or snowy days.
2 The relative humidity of the atmosphere exceeds 90%.
3 The wind speed exceeds 2.2m/s (gas shielded welding), the wind speed exceeds 8m/s (coated electrode manual arc welding), and the wind speed exceeds 11m/s (flux cored wire self-shielded welding).
4 When the ambient temperature is lower than the temperature specified in the welding procedure. 5 The lowest ambient temperature allowed for welding of commonly used pipes: -20°C for low carbon steel, -15°C for low alloy steel, and 5°C for low alloy high strength steel.
5.2.3 The type of pipe butt joints shall comply with the provisions of Article 3.1.4 of this specification. 5.2.4 When welding the pipe assembly, the groove and its inner and outer surfaces shall be cleaned manually or mechanically to remove oil, paint, rust, burrs and other dirt within 100mm of the pipe edge. 5.2.5 The position of the pipe butt weld shall meet the following requirements: 1 The distance between two adjacent welds shall not be less than 1.5 times the nominal diameter of the pipe, and shall not be less than 150mm. 2 The distance between the butt weld of the pipe and the support bracket shall not be less than 50mm, and the distance between the weld that needs heat treatment and the support bracket shall not be less than 300mm. 384
3 The distance between the butt weld of the pipe and the starting point of the bend shall not be less than 100mm and shall not be less than the outer diameter of the pipe. 4 The straight weld of the straight seam pipe should be located in a position that is easy to inspect and should not be at the bottom. 5.2.6 The elbows used on the process pipeline should be ordered according to demand and must be straight-mouthed butt welded. SY 0402—2000
5.2.7 During welding, it is strictly forbidden to strike an arc on the pipe wall outside the groove; the ground wire of the welding machine should have a reliable connection method to prevent and avoid the generation of electric arc between the ground wire and the pipe wall and burn the pipe.
5.2.8 For prefabricated anti-corrosion pipe sections, effective protection measures should be taken for the anti-corrosion layer at the pipe end before welding to prevent arc burns. 5.2.9 During pipeline welding, the root weld must be fully melted and the back side must be well formed; the root weld and hot weld should be carried out continuously, and the interval between other layers should not be too long, and the welds should be completed on the same day.
5.2.10 After each welding, the slag should be carefully cleaned, and certain defects should be removed before proceeding to the next process. 5.2.11 After each weld is completed, the welder or work group code and serial number should be marked 100mm downstream of the weld by writing or pasting. It is strictly forbidden to mark with methods that damage the parent material. 5.3 Welding heat treatment
5.3.1 Preheating and post-weld heat treatment of welded joints shall be determined in the welding process assessment according to the design requirements and the rigidity of the weldment structure.
5.3.2 When welding dissimilar steels, the preheating temperature shall be determined according to the requirements of the steel with poor weldability. 5.3.3 Preheating shall be carried out evenly on both sides of the weld and in the circumferential direction, and local overheating shall be prevented. The preheating width shall be 100mm on both sides of the weld. 5.3.4 For welding with preheating requirements, the interlayer temperature during the welding process shall not be lower than its preheating temperature. 5.3.5 Post-heating and heat treatment shall be carried out according to the process regulations determined in the welding process assessment. 5.3.6 The heating range of heat treatment shall be greater than 3 times the width of the weld on both sides of the weld and not less than 25mm. The 100mm range outside the heating zone shall be insulated.
5.3.7 The weld after heat treatment shall meet the requirements of design regulations, otherwise the weld shall be reheat treated. The number of heat treatments for a weld shall not exceed two times.
5.4 Inspection and acceptance of welds
5.4.1 The butt weld of the pipeline shall be 100% visually inspected. The visual inspection shall comply with the following provisions: 1 The weld slag and surrounding spatter shall be cleaned up, and there shall be no defects of arc burning the parent material. 2 The allowable misalignment of the weld shall not exceed 10% of the wall thickness and shall not exceed 1.6mm. 3 The width of the weld shall be 1 to 2mm widened on both sides of the upper mouth of the groove. 4 The surface excess height of the weld shall be 0 to 1.6mm, and the local part shall not be greater than 3mm and the length shall not be greater than 50mm. 5 The weld shall be neat and even, without cracks, incomplete penetration, pores, slag inclusions, burn-through and other defects. 6 Undercut is allowed in the local cover weld. The bite depth shall not exceed 12.5% of the pipe wall thickness and shall not exceed 0.8mm. In any 300mm continuous length of the weld, the cumulative bite length shall not exceed 50mm. 5.4.2 After the weld appearance inspection is qualified, it shall be subjected to non-destructive testing. Radiographic testing shall be carried out in accordance with the provisions of "Radiographic Photography and Quality Grading of Butt Welds of Petroleum and Natural Gas Steel Pipelines" SY4056. Ultrasonic testing shall be carried out in accordance with the provisions of "Ultrasonic Testing and Quality Grading of Butt Welds of Petroleum and Natural Gas Steel Pipelines" SY4065. 5.4.3 Non-destructive testing of welds shall be carried out by testers who have passed the "Non-destructive Testing Personnel Examination Rules" formulated by the Boiler and Pressure Vessel Non-destructive Testing Personnel Qualification Assessment Committee and obtained the corresponding qualification certificate, and film evaluation shall be carried out by testers who have obtained Grade II qualification certificates or above.
5.4.4 The proportion of non-destructive testing and the acceptance level shall meet the design requirements. If there are no regulations, the following regulations shall apply: 1 The number and qualified level of non-destructive testing of pipeline butt welds shall comply with the provisions of Table 5.4.4 of this specification. 2 Pipeline welds crossing station roads and welds of joints after pressure testing shall be 100% radiographically inspected. The qualified level shall comply with the provisions of Table 5.4.4 of this specification.
3 For welds in areas where ultrasonic or radiographic testing is not possible, penetration or magnetic particle testing shall be carried out in accordance with the "Industrial Metal Pipeline Engineering Construction and Acceptance Specifications" GB50235. No defects are considered qualified. 385
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