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GB/T 40068-2021: Electrofusion welding sleeve(tape) for thermal insulation pipeline
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Electrofusion welding sleeve(tape) for thermal insulation pipeline
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GB/T 40068-2021
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Basic data | Standard ID | GB/T 40068-2021 (GB/T40068-2021) | | Description (Translated English) | Electrofusion welding sleeve(tape) for thermal insulation pipeline | | Sector / Industry | National Standard (Recommended) | | Classification of Chinese Standard | P46 | | Word Count Estimation | 18,117 | | Issuing agency(ies) | State Administration for Market Regulation, China National Standardization Administration | GB/T 40068-2021: Electrofusion welding sleeve(tape) for thermal insulation pipeline---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.
(Electric heating fuse sleeve (band) for circulating pipeline)
ICS 91.140.10
P46
National Standards of People's Republic of China
Electric fuse sleeve (band) for thermal insulation pipe
Released on 2021-05-21
2021-12-01 implementation
State Administration of Market Supervision and Administration
Issued by the National Standardization Management Committee
Table of contents
Foreword Ⅲ
1 Scope 1
2 Normative references 1
3 Terms and definitions 2
4 Mark 2
5 Product form and size 3
6 Requirements 5
7 Test method 8
8 Inspection rules and inspection items 12
9 Marking and packaging 13
10 Transport and storage 13
Electric fuse sleeve (band) for thermal insulation pipe
1 Scope
This standard specifies the marking, product form and specification size, requirements, and tests of high-density polyethylene electric heat-melting sleeves (bands) for thermal insulation
Methods, inspection rules, marking and packaging, transportation and storage.
This standard is applicable to the electric melting sleeves (bands) used for the repair of high-density polyethylene outer sheath polyurethane thermal insulation pipes.
2 Normative references
The following documents are indispensable for the application of this document. For dated reference documents, only the dated version applies to this article
Pieces. For undated reference documents, the latest version (including all amendments) is applicable to this document.
GB/T 1040.1 Determination of tensile properties of plastics Part 1.General
GB/T 1408.1 Insulating material electric strength test method Part 1.Test under power frequency
GB/T 1633 Thermoplastics Determination of Vicat Softening Temperature (VST)
GB/T 3280 stainless steel cold-rolled steel plate and strip
GB/T 3682.1 Plastic thermoplastic melt mass flow rate (MFR) and melt volume flow rate (MVR) measurement
Part 1.Standard Methods
GB/T 6146 Test method for resistivity of precision resistance alloy
GB/T 7141 Plastic Thermal Aging Test Method
GB/T 8804.3 Determination of tensile properties of thermoplastic pipes-Part 3.Polyolefin pipes
GB/T 10612 Industrial sieve plate with round hole and square hole sieve plate thickness < 3mm
GB/T 18475 Thermoplastic pressure pipes and pipe fittings material classification and naming overall use (design) coefficient
GB/T 23257 Polyethylene anti-corrosion coating for buried steel pipelines
GB/T 29046 Testing method for technical indicators of prefabricated direct-buried thermal insulation pipelines for urban heating
GB/T 29047 High-density polyethylene outer protective pipe rigid polyurethane foam plastic prefabricated direct buried insulation pipe and pipe fittings
GB/T 31838.2 Dielectric and resistance characteristics of solid insulating materials Part 2.Resistance characteristics (DC method) Volume resistance and
Volume resistivity
ISO 6721-1 Plastics Determination of Dynamic Mechanical Properties Part 1.General Principles (Plastics-Determination of Dynamic
mechanicalproperties-Part 1.Generalprinciples)
ISO 6721-4 Plastics-Determination of Dynamic Mechanical Properties Part 4.Tensile Vibration Non-Resonance Method (Plastics-Determinationof
dynamicmechanicalproperties-Part 4.Tensilevibration-Non-resonancemethod)
EN489 District heating pipeline direct-buried hot water pipe network with prefabricated thermal insulation piping system steel working pipe connection joints, polyurethane protection
Thermolayer and polyethylene outer protective pipe (Districtheatingpipes-Preinsulatedbondedpipesystemsfordirectlyburiedhot
waternetworks-Jointassemblyforsteelservicepipes,polyurethanethermalinsulationandoutercas-
ingofpolyethylene)
NACERP0303 Field Application Standard of Heat Shrinkable Tubing for Pipeline. Application, Performance and Quality Control (Standard Recommended
PracticeField-AppliedHeat-ShrinkableSleevesforPipelines. Application, Performance, andQualityControl)
3 Terms and definitions
The following terms and definitions defined in GB/T 23257, GB/T 29046, and GB/T 29047 apply to this document.
3.1
Split polyethylene electrofusion welding sleeve
The structure of the electric fuse sleeve in which the high-density polyethylene sleeve (sheet) is separated from the electric fuse screen.
Note. According to the structure of the base material, it can be divided into split seamless electric fuse sleeve and split butt welding electric fuse sleeve.
3.2
One-piece electric melting sleeve integralplatetypepolyethyleneelectrofusionweldingsleeve
High-density polyethylene sheet (board) material around the inner surface (both ends) through a certain process heat-sealing embedded in the patch material formed by special electric fuse mesh,
After being energized and heated, it can be fused with the outer protective tube of the thermal insulation pipe to form a waterproof protective structural part.
3.3
Polyethyleneelectrofusionwelding tape
High-density polyethylene slats are heat-sealed and embedded with special electric fuse meshes to form a connecting structure.
3.4
Substrate
High-density polyethylene plate, ribbon or tube (sleeve)-shaped materials required for making electric heating fuse sleeves (belts).
3.5
Electrofusionweldingnet
It is made of nickel and chromium thin-walled stainless steel plate by high-pressure punching machine, which is used to heat the electric heating element of the electric heating melting sleeve (belt) and the outer sheath of the pipeline.
4 mark
The composition and meaning of the product mark should meet the following requirements.
□ □ □-□-□
Electric fuse screen width/mm;
Substrate size (thickness × width × length)/mm;
Outer protective tube diameter/mm;
Product type (one-piece or split sleeve. TY, TF; belt. D);
Product code (DRR).
Example 1.
An integrated electric heater with an electric fuse screen with a width of 50mm, a base material size of (thickness 8.5×width 600×length 2600) mm, and outer protective tube outer diameter of 760mm
The fuse is marked as.
DRRTY760-8.5×600×2600-50
Example 2.
The electric fuse mesh width is 100mm, the size of the base material is (thickness 7.5×width 70×length 4000) mm, and the outer diameter of the outer protective tube is 1200mm.
Recorded as.
DRRD1200-7.5×70×4000-100
6.4.2.2 The grid distribution of the electric fuse screen should be uniform and consistent in shape and size, and the size deviation should not be greater than ±5% of the nominal value.
6.4.3 Resistance per unit length
The resistance value per unit length of the electric fuse screen should be 0.5Ω/m~3.0Ω/m, and the deviation value should be less than or equal to ±5% of the nominal value.
6.5 Welding performance of electric heating fuse (belt)
6.5.1 After the electrothermal fuse (belt) is welded, the tensile shear strength of the welding surface shall not be lower than the strength of the base material of the outer protective pipe, and shall not be less than 19MPa.
The crack point should be located outside the weld zone.
6.5.2 After the electrothermal fuse (belt) is welded, according to EN489, the welding surface should be able to withstand the effects of temperature changes. Thermal shock
(225℃, 4h) After the test, there should be no cracks, no flow, no drooping.
6.5.3 After the electrothermal fuse (belt) is welded, the welding surface shall be immersed in heat-resistant water (boiling water, 96h) after the test, and there shall be no defects such as bubbling, delamination, and welding.
7 Test method
7.1 Appearance
The appearance is inspected by visual inspection.
7.2 Dimensional deviation
Dimension deviation inspection shall be carried out in accordance with the provisions of GB/T 29046.
7.3 Performance of base material of electric fuse sleeve (belt)
7.3.1 The density test method shall be implemented in accordance with the provisions of GB/T 29046.
7.3.2 The tensile strength test method shall be implemented in accordance with the provisions of GB/T 29046, and samples shall be taken in both the circumferential and axial directions.
7.3.3 The elongation at break test method GB/T 29046 shall be implemented, and samples shall be taken in both the circumferential and axial directions.
7.3.4 The melt flow rate test method shall be implemented in accordance with the provisions of GB/T 3682.1.
7.3.5 The Vicat softening point test method shall be implemented in accordance with the provisions of GB/T 1633.
7.3.6 The embrittlement temperature test method shall be implemented in accordance with the requirements of ISO 6721-1 and ISO 6721-4, and shall meet the following requirements.
a) The sample is made of high-density polyethylene pellets made of base material. The size of the sample should be 15mm×6mm×1.5mm.
The number of samples is at least 2;
b) The test should be carried out 24 hours after the compressed tablet is made;
c) The test instrument should meet the relationship between the dynamic thermomechanical properties of the test material and the frequency, temperature, and time, and the temperature measurement accuracy should be
0.5°C. It can record the change curve of the loss factor of the sample with temperature when the load is loaded with different frequencies;
d) The test should adopt the tensile mode, the test frequency is 1Hz, and the temperature should be kept constant for 5min when the temperature drops to -100℃, and then at a rate of 2℃/min.
The rate is raised to 20°C. The pre-tension strain should be 0.8% of the sample length, and the strain amplitude should be 0.5% of the sample length. Take all
The arithmetic mean of the sample is used as the test result, and the result is accurate to 0.1°C.
7.3.7 The environmental stress cracking resistance test method shall be implemented in accordance with the provisions of GB/T 29046.
7.3.8 The electric strength test method shall be implemented in accordance with the provisions of GB/T 1408.1.
7.3.9 The oxidation induction time test method shall be implemented in accordance with the provisions of GB/T 29046.
7.3.10 The volume resistivity test method shall be implemented in accordance with the provisions of GB/T 31838.2.
7.3.11 The chemical resistance test method shall be implemented in accordance with the provisions of GB/T 23257, and shall meet the following provisions.
a) The sample should be evenly distributed from the base material in the circumferential direction (length) and axial direction (width), and cut in parallel. The size of the sample should be.200mm×
50mm. Prepare 4 groups of samples for each sample, and the number of samples in each group should not be less than 3 in each direction.
When it is less than 450mm, 4 samples shall be taken in each direction of each group.
b) The sample should be tested after being placed in a standard laboratory environment for 8 hours.
c) The specimen shall be prepared as a dumbbell-shaped specimen according to the provisions of GB/T 1040.1 and GB/T 8804.3.
d) Determine the initial tensile strength and elongation at break of a group of samples.
e) The chemical reagent ratio of the test solution should be in accordance with Table 7.Use a constant temperature water bath to adjust the prepared solution to 23℃±
At 2℃, immerse 1 set of dumbbell-shaped specimens in 3 kinds of solutions. There should be no bubbles on the surface of the specimens or exposed liquid surface, and between the specimens
There should be no contact between the test piece and the container wall. Shake the container once a day, take out the test piece from the solution after soaking for 168h, and use water
Rinse the surface of the test piece, and then absorb the water with filter paper.
It is accurate to 0.1MPa, and the result of elongation at break is accurate to 1%.
7.3.13 The long-term mechanical performance test method shall be implemented in accordance with the provisions of GB/T 29046.
7.4 Electric fuse screen
7.4.1 The test method of material composition shall be implemented in accordance with the provisions of GB/T 3280.
7.4.2 The net size and deviation inspection shall be carried out in accordance with the provisions of GB/T 10612, and shall meet the following provisions.
a) Visually inspect the condition of the sample to be tested, and perform measurement in an area selected arbitrarily in an area with a larger error.
b) Along the length of the electric fuse screen, measure the two diagonal lines of 20 continuous grids with a digital vernier caliper with an accuracy of 0.01mm
The length and grid size of the diamond-shaped electric fuse are shown in Figure 4.Calculate the grid area according to formula (4), and use the arithmetic average of 20 grid areas
The average value is used as the test result, and the result is accurate to 0.01mm2.
c) Along the length of the electric fuse screen, measure the four metal edges of 10 continuous grids with a digital vernier caliper with an accuracy of 0.01mm
The width of the frame (not including the width of the metal part of the four corners of each grid), see Figure 4.Calculate the width of the metal frame of the grid according to formula (5) to
The arithmetic average of the frame width of 10 grids is used as the test result, and the result is accurate to 0.01mm.
7.4.3 The test method for the resistance value per unit length shall be implemented in accordance with the provisions of GB/T 6146, and shall meet the following provisions.
a) The number of samples is 3, the length of the sample should not be less than 500mm, and the width should be the actual width;
b) Use electrical measuring equipment and its supporting devices with a resolution of not less than 1×10-4Ω. Length measurement adopts special fixture to measure,
The minimum graduation value should be less than 0.1mm;
c) The test environment temperature should be 20℃±1℃, and the relative humidity of the environment should not be greater than 80%;
d) Calculate the resistance value per unit length according to formula (6), take the arithmetic average of all samples as the test result, and take 4 significant digits.
7.5 Welding performance of electric fuse sleeve (band)
7.5.1 The tensile shear strength of the welding surface shall be implemented in accordance with the provisions of GB/T 29046, and shall meet the following requirements.
a) The tensile shear strength test specimens of the welding surface of the electric fuse sleeve shall be taken from the electric fuse sleeve 24 hours after the welding is completed in a uniform position along the circumferential direction.
In this way, the sample size should be.200mm×30mm, of which.200mm is parallel to the axial direction of the insulated pipe. Circumferential direction
When the length is not less than 450mm, 8 samples shall be prepared. The one-piece electric heating fusion sleeve should also be taken evenly along the lap of the pipe axis.
3 samples, of which.200mm is perpendicular to the axial direction of the insulated pipe. The tensile-shear strength test specimens of the welding surface of the electric heating tape shall be from the welding
Take 3 specimens uniformly along the ring direction on the electrothermal melting tape after 24h. The specimen size should be.200mm×30mm, among which
200mm is parallel to the axial direction of the insulation pipe. The welding surface of the sample taken should be in the middle of the length of the sample, and use
Machining methods are used to prepare dumbbell-shaped specimens that meet the requirements of GB/T 8804.3.
b) The sample should be tested after being placed in a standard laboratory environment for 8 hours.
c) The sample should not be twisted during the test, and the test fixture should be a chuck with adjustable eccentricity.
d) The tensile shear strength is calculated according to the maximum force recorded by the testing machine and the area of the sample collection, and the position where the sample breaks should not occur
Within the welding surface. Take the arithmetic average of the tensile shear strength of multiple samples as the test result, and the result is accurate to 0.1MPa.
e) The tensile-shear yield stress is based on the initial area of the specimen and is calculated according to formula (7).
7.5.2 The thermal shock test method shall be implemented in accordance with the provisions of NACERP0303 and GB/T 23257, and shall meet the following provisions.
a) The thermal shock samples of the electric fuse sleeve shall be taken from the electric fuse sleeve 24 hours after the welding is completed, and 3 samples shall be taken from the uniform position along the ring direction.
The inch should be 300mm×80mm, of which 300mm is parallel to the axial direction of the insulation pipe; the integrated electric heating fuse should also be along the pipe
Take 3 samples evenly at the lap joints in the axial direction, of which 300mm is perpendicular to the axial direction of the insulated pipe. Thermal shock test of electric heating tape
The sample should be taken from the electric melting tape 24h after the welding is completed, and 3 samples should be taken evenly along the ring direction. The sample size should be 300mm×
80mm, of which 300mm is parallel to the axial direction of the insulation pipe. The welding surface of the sample taken should be in the middle of the length of the sample
position.
b) The sample should be tested after being placed in a standard laboratory environment for 8 hours.
c) Constant temperature of an electric heating blast drying oven with an accuracy of ±2℃ to 225℃, and hang the sample in the box, between the samples and inside the box
There should be no contact between the walls. After 4h, take out the sample and cool to room temperature. Observe the specimens, all specimens should be free of flow, cracks, or sagging
Drops are qualified.
7.5.3 The heat-resistant water immersion test method shall be implemented in accordance with the provisions of GB/T 23257, and shall meet the following provisions.
a) The heat-resistant water immersion test specimens of the electric fuse sleeve shall be taken from the electric fuse sleeve 24 hours after the welding is completed, and 3 samples shall be taken from the uniform position along the ring direction.
The sample size should be 300mm×80mm, of which 300mm is parallel to the axial direction of the insulation pipe; the integrated electric heating fuse should also
Take 3 samples evenly along the pipe's axial lap joint, of which 300mm is perpendicular to the axial direction of the insulated pipe. Heat resistance of electric melting tape
The water immersion test specimens shall be taken from the electric heating tape 24h after the welding is completed, and 3 test specimens shall be evenly taken along the ring direction. The size of the test specimens shall be
300mm×80mm, of which 300mm is parallel to the axial direction of the insulation pipe. The welding surface of the sample taken should be at the length of the sample
The middle position of the degree.
b) The sample should be tested after being placed in a standard laboratory environment for 8 hours.
c) Perform the state adjustment before the test according to the time specified in Table 8, and adjust the temperature to the test temperature.
d) After completing the sample adjustment, start the test timing. After the specified test time is reached, take out the test piece, wipe the test piece dry, and cool it to the room
temperature. Visually observe the test piece, there should be no bubbling on the surface of the electric fuse sleeve, and whether there is delamination or open welding on the welding lap surface.
8 Inspection rules and inspection items
8.1 Inspection classification
8.1.1 Product inspection is divided into factory inspection and type inspection.
8.1.2 The inspection items shall be implemented in accordance with the provisions of Table 9.
8.2 Factory inspection
8.2.1 The product shall be inspected and qualified before leaving the factory, and the inspection report shall be attached.
8.2.2 The factory inspection is divided into all inspections and sampling inspections.
8.2.3 For all inspections, all products shall be inspected piece by piece according to the inspection items.
8.2.4 Sampling inspection of electric heating fuse sleeves shall be carried out for every 300 pieces, and electric heating fuse sampling inspection shall be carried out once every 800m.
8.2.5 When there are unqualified samples, sampling should be doubled. If one of them is still unqualified, the batch of products shall be judged as unqualified.
8.3 Type inspection
8.3.1 Type inspection shall be carried out in any of the following situations.
a) Trial production, finalization and appraisal of new products or transfer of old products to factory production;
b) When raw materials and processes have undergone major changes, which may affect product performance;
c) When production resumes after stopping production for more than half a year;
d) Every 2 years of normal production.
8.3.2 Sampling shall meet the following requirements.
a) Each selected specification only represents an electric fuse sleeve (band) suitable for 0.5 times the outer diameter of the outer protective tube and upwards 2 times the outer diameter of the outer protective tube.
Specification range;
b) 1 piece for each selected specification.
8.3.3 The qualification judgment shall meet the following requirements.
a) When all the inspection items of all samples meet the requirements, the batch of products is determined to be qualified.
b) When there are unqualified items, sampling should be doubled for re-inspection. When the re-inspection meets the requirements, the product is determined to be qualified; when the re-inspection is still unqualified
Item, the batch of products is determined to be unqualified.
9 Marking and packaging
9.1 The following items should be marked on the product body.
a) Product specifications and models;
b) Product production date;
c) At least the product melt mass flow rate should be indicated.
9.2 The packaging materials should have moisture-proof performance, and the following items should be marked on the packaging.
a) Product name;
b) the number of products;
c) The name of the manufacturer;
d) Product conformity mark;
e) factory site;
f) Implementation standard (No. of this standard).
10 Transportation and storage
10.1 The product should be protected from sun and rain during transportation.
10.2 The products should be stored in a dry and ventilated warehouse, and should be stacked separately according to types and specifications, avoid heavy pressure, and keep away from sources of ignition and corrosiveness.
medium.
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