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GB/T 23257-2017 English PDF

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GB/T 23257-2017: Polyethylene coating for buried steel pipeline
Status: Valid

GB/T 23257: Historical versions

Standard IDUSDBUY PDFLead-DaysStandard Title (Description)Status
GB/T 23257-2017348 Add to Cart 1 days Polyethylene coating for buried steel pipeline Valid
GB/T 23257-2009RFQ ASK 6 days Polyethylene coating for buried steel pipeline Obsolete

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Basic data

Standard ID: GB/T 23257-2017 (GB/T23257-2017)
Description (Translated English): Polyethylene coating for buried steel pipeline
Sector / Industry: National Standard (Recommended)
Classification of Chinese Standard: E98
Classification of International Standard: 75.200
Word Count Estimation: 41,477
Date of Issue: 2017-05-12
Date of Implementation: 2017-12-01
Older Standard (superseded by this standard): GB/T 23257-2009
Quoted Standard: GB/T 1040.2; GB/T 1408.1; GB/T 1410; GB/T 1633; GB/T 1725; GB/T 1842; GB/T 3682; GB/T 4472; GB/T 5470; GB 6514; GB/T 6554; GB/T 7124; GB 7692; GB/T 8923.1; GB/T 13021; GB/T 15332; GB/T 18570.3; GB/T 18570.9; GB/T 50087; GB 50369
Issuing agency(ies): General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China, Standardization Administration of the People's Republic of China
Summary: This standard specifies the minimum technical requirements for steel pipe extruded polyethylene coating and radiation crosslinked polyethylene heat shrinkable tape (sets). This standard is applicable to the design, production and inspection of extruded polyethylene anticorrosive coatings for buried steel pipes, and the design, construction and inspection of the site filling. Other laying of the pipe in the form of extruded polyethylene coating can refer to the implementation. Extruded polyethylene coating can be divided into the highest design temperature does not exceed 60 �� under normal temperature (N) and the maximum design temperature does not exceed 80 �� high temperature type (H) two categories.

GB/T 23257-2017: Polyethylene coating for buried steel 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.
Polyethylene coating for buried steel pipeline ICS 75.200 E98 National Standards of People's Republic of China Replace GB/T 23257-2009 Buried steel pipeline polyethylene anti-corrosion layer Released on.2017-05-12 2017-12-01 implementation General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China China National Standardization Administration issued

Content

Foreword III 1 Scope 1 2 Normative references 1 3 Terms and Definitions 1 4 anti-corrosion layer structure 2 5 Material 3 5.1 Steel pipe 3 5.2 Anti-corrosion material 3 5.3 Process Evaluation Test 6 6 coating coating 7 7 Quality Inspection 8 8 signs, stacking and handling 9 9 mouth and injury 9 9.1 Filling material 9 9.2 Filling construction preparation 12 9.3 Filling construction 12 9.4 Filling quality inspection 13 9.5 Repair 13 10 Ditch backfill 14 11 Safety, health and environmental protection 14 12 Handling documents 14 Appendix A (Normative) Test Method for Curing Time of Epoxy Powders 15 Appendix B (Normative) Test methods for thermal properties of epoxy powders and their coatings 17 Appendix C (Normative) Method for determination of adhesion of anti-corrosion coatings 20 Appendix D (Normative Appendix) Anti-corrosion layer cathodic disbonding test method 21 Appendix E (Normative Appendix) Anti-corrosion test method for anti-corrosion layer 23 Appendix F (Normative Appendix) Method for determination of oxidation induction period 25 Appendix G (Normative Appendix) Test Method for Determination of Moisture Content of Plastics 26 Appendix H (Normative) Determination of indentation hardness 27 Appendix I (Normative) Test Method for Chemical Resistance of Polyethylene to Chemicals 28 Appendix J (Normative Appendix) Test Method for Ultraviolet Light Aging Resistance of Polyethylene 29 Appendix K (normative appendix) Method for determination of peel strength of anti-corrosion layer 30 Appendix L (normative appendix) Test method for impact strength of anti-corrosion layer 32 Appendix M (Normative) Test method for hot water immersion of polyethylene anti-corrosion layer 33 Appendix N (Normative Appendix) Heat Shrink Tape (Set) Thermal Shock Test Method 34 Appendix O (Normative) Test method for embrittlement temperature of hot melt adhesives 35 Appendix P (normative appendix) Test method for hot water immersion of joint anti-corrosion layer 36 Appendix Q (normative appendix) Test method for heat aging of joint anti-corrosion layer 37

Foreword

This standard was drafted in accordance with the rules given in GB/T 1.1-2009. This standard replaces GB/T 23257-2009 "buried steel pipeline polyethylene anti-corrosion layer". Compared with GB/T 23257-2009, mainly The technical changes are as follows. --- Adjusted the definition of the highest temperature for the classification of extruded polyethylene anti-corrosion layer, adjusted from "maximum use temperature" to "highest design temperature" Degree", the temperature value is adjusted from 50 ° C to 60 ° C, 70 ° C adjusted to 80 ° C (see Chapter 1); --- Added terms and definitions (see Chapter 3); --- Revised the thermal characteristics of epoxy powder coatings (see Table 2); --- Revised the tensile performance requirements of polyethylene special materials (see Table 5); --- Supplementary modification of the performance requirements of polyethylene anti-corrosion layer (see Table 7); --- Supplementary modification of the performance requirements of heat shrinkable tape joint materials (see Table 11); --- Increased the requirements for repair preparation and filling process assessment (see 9.2); --- Revised some of the appendix test methods (see Appendix B, Appendix K); --- Added appendix test method (see Appendix G, Appendix M, Appendix Q). This standard was proposed by China National Petroleum Corporation. This standard is under the jurisdiction of the National Oil and Gas Standardization Technical Committee (SAC/TC355). This standard is drafted by. China Petroleum Group Engineering Technology Research Institute, China National Petroleum Corporation Ocean Engineering Co., Ltd. Participated in the drafting of this standard. Baoji Petroleum Pipe Co., Ltd., Daqing Oilfield Engineering Construction Co., Ltd. Tianyu Design Institute. The main drafters of this standard. Zhang Qibin, Liu Jinxia, He Lian Jianfeng, Wen Hongwei, Chen Shouping, Shi Huihui. The previous versions of the standards replaced by this standard are. ---GB/T 23257-2009. Buried steel pipeline polyethylene anti-corrosion layer

1 Scope

This standard specifies the minimum technical requirements for steel pipe extrusion polyethylene anti-corrosion layer and radiation cross-linked polyethylene heat shrinkable tape (set). This standard is applicable to the design, production and inspection of extruded polyethylene pipe anti-corrosion layer, and the design, construction and on-site filling test. Other laying forms of extruded polyethylene anti-corrosion coatings can be referred to. Extrusion polyethylene anti-corrosion layer can be divided into normal temperature type (N) with maximum design temperature not exceeding 60 °C and maximum design temperature not exceeding 80 °C High temperature type (H) two types.

2 Normative references

The following documents are indispensable for the application of this document. For dated references, only dated versions apply to this article. Pieces. For undated references, the latest edition (including all amendments) applies to this document. Determination of tensile properties of plastics - Part 2. Test conditions for moulding and extruded plastics GB/T 1408.1 Test methods for electrical strength of insulating materials - Part 1 GB/T 1410 solid insulating material volume resistivity and surface resistivity test method GB/T 1633 Determination of Vicat softening temperature (VST) of thermoplastics GB/T 1725 Determination of non-volatile content of paints, varnishes and plastics GB/T 1842 plastic polyethylene environmental stress cracking test method GB/T 3682 Thermoplastic melt mass flow rate and melt volume flow rate determination GB/T 4472 Determination of density and relative density of chemical products Determination of embrittlement temperature of GB/T 5470 plastic impact method GB 6514 Painting operation safety regulations Painting process safety and ventilation purification GB/T 6554 - Resin-based composites for electrical insulation - Part 2. Test method GB/T 7124 Determination of tensile shear strength of adhesives (rigid materials to rigid materials) GB 7692 Painting operation safety regulations Pre-painting process safety and ventilation purification GB/T 8923.1.Determination of surface cleanliness of steels - Part 1 . Uncoated steel Corrosion grade and treatment grade of the surface of the steel after surface and overall removal of the original coating GB/T 13021 Determination of carbon black content of polyethylene pipes and fittings (thermal weight loss method) GB/T 15332 Determination of softening point of hot melt adhesives GB/T 18570.3.Determination of surface cleanliness of steels -- Part 3. Surface dust evaluation (pressure sensitive tape method) GB/T 18570.9 Evaluation of surface cleanliness of steels before coatings -- Part 9. Conductivity measurement GB/T 50087 industrial enterprise noise control design specification GB 50369 Oil and Gas Long Distance Pipeline Engineering Construction and Acceptance Specifications

3 Terms and definitions

The following terms and definitions apply to this document. 3.1 Extruded polyethylene coating with extrudedpolyethylenecoating In the extruder, by heating and pressurizing, the polyethylene is continuously flowed through the extrusion die to form a coating on the pipe. The coating layer comprises a longitudinal extrusion coating and a lateral wrapping coating. 3.2 Maximum design temperature maximumdesigntemperature The maximum temperature that the coating may reach during pipeline transportation, handling, construction, and operation. 3.3 Maximum operating temperature maximumoperationtemperature The highest temperature reached by a pipe or pipeline system during operation. Note. The maximum operating temperature does not exceed the maximum design temperature. 3.4 Low temperature coated epoxy powder coating lowtemperatureappliedepoxypowdercoating It is used as the bottom layer of the three-layer polyethylene anti-corrosion layer specified in this standard, and can be applied to epoxy powder coatings below.200 °C. 3.5 Fracture nominal strain nonlineartensilestrainatbreak Tensile nominal strain corresponding to tensile fracture stress. 3.6 Cohesive failure cohesivefailure The adhesive layer itself ruptures and adhesive bonds exist on both surfaces of the adherend. 3.7 Interface destruction interfacialfailure A visually visible damage occurs at the interface between the adhesive layer and the adherend. 4 anti-corrosion layer structure 4.1 Extruded polyethylene anti-corrosion layer is divided into two layers and two layers. The bottom layer of the two-layer structure is an adhesive layer, and the outer layer is a polyethylene layer; The bottom layer of the three-layer structure is usually an epoxy powder coating, the middle layer is an adhesive layer, and the outer layer is a polyethylene layer. Pipes above DN500 are not suitable A two-layer polyethylene anti-corrosion layer is used. 4.2 The minimum thickness of the coating shall comply with the requirements of Table 1. The thickness of the anti-corrosion layer at the weld site shall not be less than 80% of the value specified in Table 1. should According to the pipeline construction environment and operating conditions, select the grade of the anti-corrosion layer. Table 1 Thickness of anti-corrosion layer Steel pipe nominal diameter DN Epoxy coating a Mm Adhesive layer Mm Minimum thickness of coating Mm Ordinary (G) Enhanced (S) DN≤100 100 \u003cDN≤250 250 \u003cDN\u003c500 500≤DN< 800 800≤DN≤1200 DN >1200 ≥120 ≥150 ≥170 1.8 2.5 2.0 2.7 2.2 2.9 2.5 3.2 3.0 3.7 3.3 4.2 a Not applicable to two-layer polyethylene anti-corrosion coating.

5 materials

5.1 Steel pipe 5.1.1 Steel pipes shall comply with the current relevant steel pipe standards or technical requirements for ordering, and have a factory certificate. 5.1.2 The visual inspection of steel pipes shall be carried out one by one. Appearance quality should comply with the current relevant standards or technical requirements for ordering, unqualified Steel pipes should not be coated with an anti-corrosion layer. 5.2 Anti-corrosion material 5.2.1 General regulations 5.2.1.1 Anti-corrosion layer All raw materials shall have the factory quality certificate and inspection report, the instruction manual, the safety data sheet, the factory certificate, Production date and expiration date. Epoxy powder coating suppliers should provide information such as the thermal characteristics of the product. 5.2.1.2 All kinds of raw materials of anti-corrosion layer should be packed well and should be stored according to the requirements of the product manual. 5.2.1.3 Each brand (type) of epoxy powder coatings, adhesives and special materials for polyethylene shall be recognized by the state before use. The inspection agency of the certificate shall be tested according to the corresponding performance items specified in 5.2. The performance test results can meet the requirements of the requirements of this standard. use. 5.2.2 Epoxy powder coating The properties of epoxy powder coatings and their coatings are to comply with Tables 2 and 3. Coating plant for each production batch (not more than 20t) epoxy Powder coatings shall be re-examined according to the requirements of Tables 2 and 3 (excluding 65 ° C, 30 d cathodic disbonding). The third item of Table 3 shall be irregular. Review. When the steel pipe has low temperature coating requirements, it should be coated with epoxy powder coating at low temperature, and the performance should meet the requirements of Table 2 and Table 3. Table 2 Performance indicators of epoxy powder coatings Project performance index test method Particle size distribution 150μm sieve powder ≤3.0 250μm sieve powder ≤0.2 GB/T 6554 Non-volatile content (105 ° C) ≥99.4 GB/T 6554 density g/cm3 1.30~1.50 and meet the manufacturer's given value ±0.05 GB/T 4472 Gel time ≥12 and meet the manufacturer's given value ±20% GB/T 6554 Curing time Min ≤3 Appendix A Thermal characteristics ΔH J/g ≥45 Tg2 ≥98

Appendix B

Note. The test temperature for the gelation time and curing time of the epoxy powder coating is the coating temperature specified in the product specification. Normal temperature coating powder test when not specified The test temperature is.200 ° C, and the low temperature coated powder test temperature is lower than.200 ° C. Table 3 Performance indicators of sintered epoxy coating Project performance index test method Adhesion

1 Appendix C

Cathodic disbondment (65 ° C, 48 h) Mm ≤5 Appendix D Cathodic disbondment (65 ° C, 30d) Mm ≤15 Appendix D Anti-bending (-20 ° C, 2.5 °) No crack Appendix E Note. The coating thickness of the laboratory sprayed test piece should be 300μm~400μm, and the coating temperature is the temperature specified in the product specification. When not specified, normal temperature coating The powder application temperature was.200 ° C, and the low temperature coating powder coating temperature was lower than.200 ° C. 5.2.3 Adhesive The properties of the adhesive shall comply with the requirements of Table 4. The coating factory shall, in accordance with the provisions of Table 4, apply adhesives for each production batch (not exceeding 30 tons). Conduct a quality re-examination. When the two-layer polyethylene anti-corrosion layer is made of hot-melt adhesive, the appropriate technical performance should be determined according to the engineering requirements. index. Table 4 Adhesive performance indicators Project performance index test method density g/cm3 0.920~0.950 GB/T 4472 Melt flow rate (190 ° C, 2.16 kg) g/10min ≥0.7 GB/T 3682 Vicat softening point (A50, 9.8N) ≥90 GB/T 1633 Embrittlement temperature ≤-50 GB/T 5470 Oxidation induction period (200 ° C) Min ≥10 Appendix F Moisture content ≤0.1 Appendix G Tensile strength a MPa ≥17 GB/T 1040.2 Fracture nominal strain a ≥600 GB/T 1040.2 a Stretching speed 50mm/min. 5.2.4 Polyethylene The properties of polyethylene special materials and their pressed sheets shall comply with the requirements of Tables 5 and 6. The coating plant gathers for each production batch (not more than 500t) Ethylene special materials shall be re-tested for the first 4 items specified in Table 5 and the first 4 items specified in Table 6. If necessary, other properties may be applied. Carry out a retest. Table 5 Performance indicators of polyethylene special materials Project performance index test method density g/cm3 0.940~0.960 GB/T 4472 Melt flow rate (190 ° C, 2.16 kg) g/10min ≥0.15 GB/T 3682 Carbon black content ≥2.0 GB/T 13021 Moisture content ≤0.1 Appendix G Oxidation induction period (220 ° C) Min ≥30 Appendix F Heat aging a (100 ° C, 4800h) ≤35 GB/T 3682 a Heat aging indicator is the rate of change of melt flow rate before and after the test. Table 6 Compressed sheet performance indicators of polyethylene special materials Project performance index test method Tensile yield strength a MPa ≥15 GB/T 1040.2 Tensile strength a MPa ≥22 GB/T 1040.2 Fracture nominal strain a ≥600 GB/T 1040.2 Vicat softening point (A50, 9.8N) ≥110 GB/T 1633 Embrittlement temperature ≤-65 GB/T 5470 Electrical strength MV/m ≥25 GB/T 1408.1 Volume resistivity Ω·m ≥1×1013 GB/T 1410 Environmental stress cracking resistance (F50) ≥1000 GB/T 1842 Table 6 (continued) Project performance index test method Indentation hardness Mm (23 ° C) (60 ° C or 80 ° C) b ≤0.2 ≤0.3

Appendix H

Chemical resistant corrosion c (soaked 7d) 10% HCl 10% NaOH 10% NaCl ≥85 ≥85 ≥85 Appendix I UV resistant aging c (336h) ≥80 Appendix J a Stretching speed 50mm/min. b Normal temperature type, test condition is 60 °C; high temperature type, test condition is 80 °C. c Resistance to chemical media and UV aging is the tensile strength after the test and the retention of the nominal strain at break. 5.3 Process evaluation test 5.3.1 Coating plant application The selected anti-corrosion layer material shall be subjected to process qualification test on the coating production line, and the performance of the anti-corrosion layer shall be inspected. Measurement. When the manufacturer of the anti-corrosion layer material or the brand (type) or the diameter of the steel pipe changes or the wall thickness increases, the process qualification test shall be repeated. work After the art evaluation test is passed, the coating plant shall carry out the coating production of the anti-corrosion layer according to the process parameters determined by the process evaluation test. 5.3.2 The performance of the polyethylene layer and the anti-corrosion layer shall comply with the requirements of Tables 7 and 8. 5.3.2.1 Apply polyethylene layer according to the determined process parameters and perform performance test. The polyethylene layer used for performance testing shall be free of glue and epoxy. Powder layer, the results should meet the requirements of Table 7. Table 7 Performance indicators of polyethylene layer Project performance index test method Tensile strength a Axial MPa ≥20 Circumference MPa ≥20 Deviation b ≤15 GB/T 1040.2 Fracture nominal strain a ≥600 GB/T 1040.2 Indentation hardness Mm (23 ° C) (60 ° C or 80 ° C) c ≤0.2 ≤0.3

Appendix H

Table 7 (continued) Project performance index test method Environmental stress cracking resistance (F50) ≥1000 GB/T 1842 Thermal stability d∣ΔMFR∣ ≤20 GB/T 3682 a Stretching speed 50mm/min. b Deviation is the ratio of the difference between axial and circumferential tensile strength to the lower of the two. c Normal temperature type, test condition is 60 ° C; high temperature type, test condition is 80 ° C. d The rate of change of melt flow rate before and after extrusion of polyethylene. 5.3.2.2 Except the test piece from the anti-corrosion pipe or the test pipe section coated under the same process conditions to test the overall performance of the anti-corrosion layer, and test The results should be in accordance with Table 8. Table 8 Performance indicators of the anti-corrosion layer project Performance Two-layer structure experiment method Peel strength N/cm (20 °C ± 5 °C) (60 ° C ± 5 ° C) ≥70 ≥35 ≥100 (cohesive failure) ≥70 (cohesive failure) Appendix K Cathodic disbondment (65 ° C, 48 h) Mm ≤15 ≤5 Appendix D Cathodic disbondment (maximum operating temperature, 30d) Mm ≤25 ≤15 Appendix D Thermal properties of epoxy powder Glass transition temperature change value ∣ΔTg∣ - ≤5 Appendix B Impact strength J/mm ≥8 Appendix L Anti-bending (-30 ° C, 2.5 °) Polyethylene without cracking Appendix E Soaking with hot water (80°C, 48h) The average depth of the warp is ≤2mm and the maximum is ≤3mm. Appendix M 6 coating of anti-corrosion coating 6.1 The surface treatment of steel pipes shall meet the following requirements. a) Before applying the anti-corrosion layer, remove the grease and dirt ......
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