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This standard specifies the scope, product classification and marking, materials, requirements, test methods, inspection rules, marking, packaging, transportation and storage of plastic-lined composite steel pipes for water supply.
This standard is applicable to plastic-lined steel pipes for water supply with a nominal diameter of not more than 500mm. It is mainly used for conveying domestic cold and hot water, and can be implemented with reference to this standard when conveying media for other purposes.
2 normative reference documents
The clauses in the following documents become the clauses of this standard by reference. All subsequent modifications (excluding errata) or revisions of dated reference documents are not applicable to this standard. However, parties who have reached an agreement according to this standard are encouraged to study whether the latest versions of these documents can be used. For undated reference documents, the latest edition is applicable to this standard.
GB/T 24 1 hydrostatic test method for metal pipelines
GB/T 244 bending test method for metal tubes
GB/T 246 metal tube flattening test method
GB/T 2 102- 1988 acceptance, packaging, marking and quality certificate of steel pipes.
GB/T 309 1 welded steel pipes for low-pressure fluid transportation
GB/T 7306.2 550 Sealing pipe thread Part 2: Tapered internal thread and tapered external thread
GB/T 8 163 seamless steel pipe for conveying fluid
GB/T 9 1 19 flat flat welded steel pipe flanges
GB/T 9 124 technical specification for steel pipe flanges
GB/T 97 1 1 technical delivery conditions for steel pipes for oil and gas industry.
GB/T 10002. 1 PVC-U pipe for water supply.
GB/T 126 1 1 technical requirements for quality control of metal parts before plating.
Ductile iron pipes, fittings and accessories for water pipes and gas pipes.
GB/T 13663 polyethylene pipe for water supply.
GB/T 15558. 1 buried polyethylene pipe for gas.
GB/T 172 19 safety evaluation standard for drinking water transmission and distribution equipment and protective materials.
GB/T 17395 dimensions, shapes, weights and allowable deviations of seamless steel pipes.
GB/T 18742.2 polypropylene piping system for cold and hot water part 2: piping
GB/T 18992.2 crosslinked polyethylene (PE-X) piping system for hot and cold water part 2: piping.
GB/T 18993.2 chlorinated polyvinyl chloride (PVC-C) piping system for hot and cold water part 2: piping.
CJ/T 120 Plastic coated composite steel pipe for water supply
CJ/T 156 Grooved Pipe Joint
CJ/T 175 heat-resistant polyethylene (PE-RT) hot and cold water piping system.
QB/T 3834 Test method for thickness of metal coating and chemical treatment layer of light industrial products-Magnetic method
SY/T 04 13 Technical Standard for Polyethylene Anticorrosion Coating of Buried Steel Pipeline
SY/T 5037 Spiral-seam Submerged Arc Welded Steel Pipe for Low-pressure Fluid Transportation Pipeline
Hygienic safety evaluation standard for drinking water transmission and distribution equipment and protective materials (200 1)No. 16 1.
3 product classification and labeling
3. 1 product classification
According to the temperature of water, it can be divided into plastic-lined steel pipes for cold water and plastic-lined steel pipes for hot water.
3.2 product marking
Product logo consists of plastic-lined steel pipe code, plastic-lined material code and nominal diameter.
□ —(□□)—DN□□
Nominal diameter mm;
Code of plastic lining material: polyethylene is PE; Heat-resistant polyethylene is PE-RT;
The crosslinked polyethylene is PE-x; Polypropylene is PP-r; Hard PVC is PVC-u;
Chlorinated polyvinyl chloride is PVC-c;
Code of plastic-lined steel pipe for cold water: SP-C;
Code of plastic-lined steel pipe for hot water: SP-Cr;
Code: PSP-C, plastic-coated steel pipe for cold water;
Code: PSP-CR, plastic-lined steel pipe for hot water.
3.2 Example of marking:
SP-CR—(PE-RT)—DN 100
Heat-resistant polyethylene lined composite steel pipe for hot water, nominal diameter 100 mm
4 materials
4. 1 base pipe (steel pipe lined with plastic):
If the foundation pipe is straight welded steel pipe, it shall meet the requirements of GB/T 309 1 for foundation pipe;
If the base pipe is spiral seam submerged arc welded steel pipe, it shall meet the requirements of SY/T 5037 for base pipe;
Seamless steel pipes shall meet the requirements of GB/T 8 163 and GB/T 17395.
When the foundation pipe is steel pipe for oil and gas industry, it shall meet the requirements of GB/T 97 1 1 for foundation pipe.
4.2 External anticorrosion
If the external anticorrosion of the base pipe is hot dip galvanized, it shall meet the requirements of GB/T 309 1 for galvanized coating;
If the external anticorrosion of the base pipe is plastic coating, it shall meet the requirements of CJ/T 120 for plastic coating;
If the external anticorrosive coating of the base pipe is covered with plastic, it shall meet the requirements of this standard and SY/T 04 13 for plastic coating;
4.3 Flange
The size of the steel flange welded to the flange on the foundation pipe shall conform to GB/T 9 1 19 or other corresponding standards;
The material of steel flange shall meet the requirements of GB/T9 124 or other corresponding standards.
4.4 socket
The size of the steel socket welded to the socket on the base pipe shall comply with GB/T 13295;
4.5 For the plastic-lined steel pipe with groove connection, the outside diameter of the base pipe shall comply with CJ/T 156.
4.6 lined with plastic
The lining plastic of polyethylene lined steel pipe for water supply shall meet the requirements of GB/T 13663 for plastics;
The polyethylene (PE) steel pipe lining plastic for gas shall meet the requirements of GB/T 1558+0 for plastics;
The lining plastic of PE-RT steel pipe for hot and cold water shall meet the requirements of CJ/T 175 for plastics;
The lining plastic of PE-X steel pipe for hot and cold water shall meet the requirements of GB/T 18992.2 for plastics;
The lining plastic of polypropylene (PP-R) steel pipe for hot and cold water shall meet the requirements of GB/T 18742.2 for plastics;
The plastic lining of rigid polyvinyl chloride (PVC-U) steel pipe for water supply shall meet the requirements of GB/T 10002.6438+0 for plastics;
The plastic lining of chlorinated polyvinyl chloride (PVC-C) steel pipes for hot and cold water shall meet the requirements of GB/T 18993.2 for plastics;
4.7 Plastic coating
The plastic coating of polyethylene-lined steel pipe should meet the requirements of SY/T 04 13 for plastics.
4.8 adhesive
The adhesive between the outer plastic coating and the steel pipe should meet the requirements of SY/T 04 13, and the adhesive between the plastic lining and the steel pipe should meet the adhesive performance requirements of the corresponding lining materials.
4.9 Surface Treatment of Base Pipe
4.9. 1 Before plastic lining, the rust, burr and dirt on the metal surface of the base should be removed by shot blasting, grinding and acid cleaning, and it should comply with GB/T 126 1 1.
4.9.2 Welded steel bars shall be removed from straight welded steel pipes, and the residual height shall not be greater than 0.5mm.. ..
5 requirements
5. 1 size
5. 1. 1 The thickness of plastic layer of plastic-lined steel pipe shall meet the requirements in Table 1.
Table 1 plastic layer thickness and allowable deviation mm
Minimum thickness of plastic layer outside plastic layer of nominal diameter DN plastic layer lining flange
Allowable deviation of thickness
151.5+0.2-0.21.0+unlimited -0.5 0.5
20 0.6
25 0.7
32 0.8
40 1.0
50 1. 1
65 1. 1
80 2.0 1.5 1.2
100 1.3
125 1.4
150 2.5 2.0 1.5
200+ Unlimited -0.5 2.0
250 3.0 2.5
300 2.2
350 3.5 3.0
celebrity
450
500 2.5
Note: See Appendix A for a comparison of the nominal diameters of metric system and English system.
5. 1.2 Generally, the length of plastic-lined steel pipe is 6m, and the allowable deviation of its total length is 20mm. Plastic-lined seamless steel pipes can be delivered according to the length agreed by both parties.
5.2 appearance
5.2. 1 The inner and outer surfaces of the plastic-lined steel pipe shall be smooth, and there shall be no bubbles, cracks, peeling, scars, depressions, uneven colors and decomposition discoloration lines.
5.2.2 Plastic-lined steel pipes shall be straight, and the sections at both ends shall be perpendicular to the pipe axis.
5.3 performance
5.3. 1 Bond strength: the bond strength between steel and plastic lining of plastic-lined steel pipe for cold water should not be less than 0.3 MPa(30N/cm2). The bond strength between steel and plastic-lined steel pipe for hot water should not be less than 1.0 MPa( 100N/cm2).
5.3.2 Bending performance: The plastic-lined steel pipe with a nominal diameter of not more than 50mm will not crack after bending, and the steel will not delaminate from the internal and external plastic layers.
Phenomenon.
5.3.3 Compressive performance: The plastic-lined steel pipe with a nominal diameter greater than 50mm will not crack after flattening, and there will be no delamination between steel and internal and external plastic layers.
Phenomenon.
5.3.4 Hygienic performance: The sanitary performance of plastic-lined steel pipes for drinking water should meet the requirements of GB/T 172 19, and the standard of Health Law Supervision and Development (200 1) 16 1 can also be implemented according to the requirements of health departments.
5.3.5 Cold and hot cycle resistance: After three cold and hot cycle tests, the plastic-lined steel pipe specimen used for conveying hot water has no defects such as deformation cracks, and its bonding strength is not lower than the value specified in Article 5.3. 1 of this standard.
hydraulic test
The foundation pipe shall be subjected to water pressure test according to the standards implemented by the foundation pipe, and the plastic-lined steel pipe shall be subjected to water pressure test during the type test. Hydrostatic test can be carried out on the whole pipeline, or on a section of pipeline together with pipe fittings. The hydrostatic test pressure and holding time shall be implemented according to the standards implemented by the base pipe.
5.3.7 Peeling strength of plastic coating: Peeling strength should not be less than 35N/cm.
6 test method
6. 1 appearance
You can visually check the appearance of the plastic-lined steel pipe.
6.2 dimensions
The dimension of plastic-lined steel pipe shall be measured with vernier caliper with accuracy of 0.02mm, and its dimension shall meet the requirements of Table 1. Measure the length with a steel tape. The thickness of plastic coating is measured by magnetic method according to QB/T3834.
6.3 adhesive strength test
Three sections of 20mm length were randomly cut from the sample tube as test pieces. For plastic-lined steel pipes with a diameter greater than DN 150, the cutting length can be changed to 10 mm, as shown in figure 1. At room temperature, the specimen is horizontally placed on the test platform, and pressure is gradually applied to the plastic-lined pipe, and the base pipe and the plastic-lined pipe are sheared, and the pressure value when the joint surface is separated is measured. According to the formula (/kloc-0
F=W/A - ( 1)
A=3. 14×D×L - (2)
Where: f-bond strength, n/cm2;
W-separation pressure, n;
A—— the area of the joint surface between steel and plastic of plastic-lined steel pipe, cm2；; ;
D—— average inner diameter of central pipe, cm;
L:- sample length, cm.
Figure 1 Bond strength test
6.4 Bending test
According to GB/T 244, cut an appropriate length on the sample tube as a test piece. At room temperature, put the sample on the mold, the sample bends 100, and the radius of curvature of the mold is 8 times the outer diameter of the sample. During the test, the sample has no filler. After the test, cut the sample from the middle of the arc and check whether there is any visible separation between the steel and the inner and outer plastic layers.
6.5 Crushing test
According to GB/T 246, cut a section with a length of not less than 50mm at any part of the finished pipe as a test piece.
At room temperature, the specimen is sandwiched between two parallel plates. As shown in Figure 2, the weld of straight welded steel pipe is 900% to the load. Then, press the sample to 3/4 of the outer diameter and check whether there is any visible separation between the steel and the inner and outer plastic layers.
Fig. 2 flattening test
6.6 Hygienic performance test
According to the test method specified in GB/T 172 19, it can also be implemented according to the test method specified in Health Law Supervision (200 1) 1.
6.7 Cold and Hot Cycle Resistance Test
Take a 200mm long pipe specimen, soak it in 950 C 20 C hot water for 30min, take it out, naturally cool it at room temperature 10min, then soak it in 50C 2°C cold water for 30 min, take it out and let it stand at room temperature 10min, that is, 1 cycle, and * * make three cycles. After that, the central part of the specimen is cut 20mm, and the bond strength test is carried out according to the provisions of Article 6.3 of this standard.
6.8 Hydraulic test
According to the test method specified in GB/T 24 1
6.9 Plastic coating peeling test
The peel strength was determined according to the test method specified in Appendix B. ..
7 inspection rules
The inspection of plastic-lined steel pipes is divided into factory inspection and type inspection.
7. 1 group batch and sampling
The assembly and sampling of plastic-lined steel pipes shall meet the requirements in Table 2.
Table 2 Provisions on Batch Setting and Sampling
Inspection Item Sampling Quantity Group Batch
When DN0mm is tested one by one, every 2000 roots will be a batch; if the remainder exceeds 200 roots, less than 200 roots will be merged into a batch; DN≥50mm, every 1000 is a batch, and the remainder is more than 100, and less than 100 is merged into one batch.
2 pieces in each batch.
Crushing test: each batch and specification 1 piece.
bending test
7.2 ex-factory inspection
7.2. 1 Each batch of products of plastic-lined steel pipes can only leave the factory after passing the inspection by the quality inspection department of the factory.
7.2.2 See Table 2 for the ex-factory inspection items and sampling quantity.
7.2.3 If one inspection item in each inspection item is unqualified, it shall be selected, and then double samples shall be taken for reinspection. If there is still one unqualified item, the batch is unqualified. However, the supplier can select the batch and accept it as a new batch.
7.3 Type inspection
7.3. 1 Type inspection shall be carried out under the following circumstances
A) When the product is finalized;
B) When the design, technology and materials of the product have changed greatly, which may affect the performance of the product;
C) When production is resumed after half a year of production suspension;
D) One year after normal production is completed;
E) When the national quality supervision and inspection organization requires type inspection.
7.3.2 Type inspection items:
The inspection items of plastic-lined steel pipes for hot water are other items except Article 5.3.7 in the "Requirements" of this standard.
The inspection items of plastic-lined steel pipes for cold water are other items except 5.3.5 and 5.3.7 in the "Requirements" of this standard.
In addition to the above two provisions, the plastic-coated lined steel pipe shall be tested in accordance with Article 5.3.7 of this standard.
In addition to the above three provisions, the plastic-lined steel pipe conveying drinking water needs to be tested as specified in Article 5.3.4 of this standard.
7.3.3 Samples for type inspection shall be randomly selected from products that have passed the ex-factory inspection.
7.3.4 If the sanitary performance of the type inspection is unqualified, the batch shall be judged unqualified, and re-inspection is not allowed.
The rest of the project inspection, if you find any one, any one is unqualified, you should double the sampling and reinspect the unqualified project. If it is still unqualified after re-inspection, it is judged that the type inspection is unqualified.
8 Marking, packaging, transportation and storage
8. 1 logo
8. 1. 1 The outer wall of the plastic-lined steel pipe shall be marked with the product mark, the name of the manufacturer, and the implementation standard number of the plastic-lined steel pipe and the base pipe.
8. 1.2 The plastic-lined steel pipe for conveying cold water adopts white (or natural) plastic-lined pipe. Plastic-lined steel pipes conveying hot water are made into red plastic-lined pipes.
8.2 packaging
Bundling and packaging shall be carried out according to Article 2. 1 02-1988, and both ends of each composite pipe shall be sealed. Each bundle of products shall be hung or pasted with two certificates, which shall include the following contents: product trademark, product name, product logo, quantity, batch number, implementation standard number of plastic-lined steel pipe and base pipe, production date, manufacturer's name, address and telephone number.
8.3 transportation
Steel pipes lined with plastic shall not be thrown or violently hit during transportation.
8.4 storage
Plastic-lined steel pipes should be stacked directly in the shade, away from heat sources and fire sources, and should not be stacked in outdoor direct sunlight or cold places for a long time.
Appendix a
500 20
Appendix b
(normative appendix)
Peel test of outer plastic coating
B. 1 This method is suitable for measuring the adhesion of plastic-coated steel pipes.
B.2 tools
B.2. 1 tubular dynamometer: the maximum range is 500N, and the minimum scale is 10N n.
B.2.2 steel ruler: the minimum scale is1mm.
B.2.3 Cutter: It can cut the plastic coating outside the pipeline.
B.2.4 surface thermometer: the accuracy is 65438 0℃.
B.3 testing
At room temperature, the outer surface temperature of the plastic coating outside the pipeline should be cut into strips with a width of 20 mm ~ 30mm and a length greater than 10mm along the circumferential direction. When cutting, cut through the plastic coating on the outside, and then pry one end up. Keep the dynamometer vertical to the surface of the steel pipe, slowly pull up the polyethylene layer and record the dynamometer value, as shown in Figure B 1.