GOST 31448-2012
GOST 31448−2012 steel Tubes with a protective outer coating for main gas and oil pipelines. Specifications
GOST 31448−2012
Group В62
INTERSTATE STANDARD
STEEL TUBES WITH A PROTECTIVE OUTER COATING FOR MAIN GAS AND OIL PIPELINES
Specifications
Steel pipes with defensive coverings for main gas and oil pipelines. Specifications
ISS 23.040.10
OKP 13 9000
Date of introduction 2014−01−01
Preface
Goals, basic principles and main procedure of works on interstate standardization have been established in GOST 1.0−92 «interstate standardization system. Basic provisions» and GOST 1.2−2009 «interstate standardization system. Interstate standards, rules and recommendations on interstate standardization. Rules of development, adoption, application, renewal and cancellation"
Data on standard
1 PREPARED by the Technical Committee for standardization TC 357 «Steel and cast iron pipes and cylinders», Open joint stock company «Russian scientific research Institute of pipe industry» (JSC «RosNITI»)
2 SUBMITTED by the Technical Committee for standardization TC 357 «Steel and cast iron pipes and cylinders"
3 ACCEPTED by the Interstate Council for standardization, Metrology and certification (Protocol of 15 March 2012 No. 49)
The standard was accepted by voting:
| Short name of the country on MK (ISO 3166) 004−97 |
Country code, pomc (ISO 3166) 004−97 | Abbreviated name of the national authority for standardization |
| Azerbaijan |
AZ | Azstandart |
| Belarus |
BY | Gosstandart Of The Republic Of Belarus |
| Kazakhstan |
KZ | Gosstandart Of The Republic Of Kazakhstan |
| Kyrgyzstan |
KG | Kyrgyzstandard |
| Russia |
EN | Rosstandart |
4 this standard is prepared based on the application of national standard of Russian Federation GOST R 52568−2006 «steel Tubes with a protective outer coating for main gas and oil pipelines. Technical conditions"
5 by Order of the Federal Agency for technical regulation and Metrology of June 5, 2013 N 143-St inter-state standard GOST 31448−2012 introduced as a national standard of the Russian Federation from January 1, 2014
6 INTRODUCED FOR THE FIRST TIME
Information about the changes to this standard is published in the annual reference index «National standards», and the text changes and amendments — in monthly information index «National standards». In case of revision (replacement) or cancellation of this standard a notification will be published in the monthly information index «National standards». Relevant information, notification and lyrics are also posted in the information system of General use — on the official website of the Federal Agency for technical regulation and Metrology on the Internet
Introduction
The need for the development of this standard due to the lack of inter-state standard for welded pipe with protective coatings taking into account the specifics of oil and gas main pipelines, oil-products pipelines with increased regulatory requirements to ensure reliability and safety in operation.
In this standard, see modern achievements in the field of quality pipe coatings, as reflected in international, regional, national regulations, scientific and technical and technological solutions.
Standard indicators technical level and quality of pipe coatings comply with foreign standards or exceed them.
1 Scope
This standard applies to seamless steel, longitudinally welded and spiral-welded pipes with a diameter of 114−1420 mm with an outer protective coating applied at the factory, used for construction and repair of trunk gas pipelines, oil pipelines and oil product pipelines.
2 Normative references
This standard uses the regulatory references to the following international standards:
GOST 9.049−91 unified system of protection from corrosion and ageing. Polymeric materials and their components. Methods of laboratory testing for resistance to fungi
GOST 9.050−75 unified system of corrosion protection and aging. Coating of paint. Methods of laboratory testing for resistance to fungi
GOST 12.1.005−88 standards System of labor safety. General hygiene requirements for working zone air
GOST 12.3.002−75 System safety standards. The process of production. General safety requirements
GOST 12.3.005−75 System safety standards. Work painting. General safety requirements
GOST 12.3.016−87 standards System of labor safety. Construction. Work corrosion. Safety requirements
GOST
GOST 411−77 rubber and glue. Methods for the determination of bond strength with metal at peeling
GOST 427−75 Rulers measuring metal. Specifications
GOST 8696−74 electric resistance welded steel Pipes with spiral seam General purpose. Specifications
GOST 10692−80 Pipe steel, cast iron and fittings to them. Acceptance, marking, packing, transportation and storage
GOST 11262−80 Plastics. Test method tensile
GOST 11645−73 Plastic. The method of determining the melt flow index of thermoplastics
GOST 13518−68 Plastic. A method of determining the resistance of polyethylene to stress cracking
GOST 14192−96 Marking of cargo
GOST 15140−78 Materials. Methods for determining the adhesion
GOST 16337−77 high-pressure Polyethylene. Specifications
GOST 17299−78 ethyl Alcohol technical. Specifications
GOST 18299−72 Materials. The method of determining the limit of the tensile strength, elongation at break and modulus of elasticity
GOST 20295−85 steel welded Pipes for main gas and oil pipelines. Specifications
GOST 25812−83 steel pipe mains. General requirements for corrosion protection
_______________On the territory of the Russian Federation GOST R 51164−98 «steel pipe mains. General requirements for corrosion protection».
GOST 28498−90 Thermometers liquid-in-glass. General technical requirements. Test methods
GOST 31447−2012 steel welded Pipes for trunk gas pipelines, oil pipelines and oil product pipelines. Specifications
Note — When using this standard appropriate to test the effect of reference standards in the information system of General use — on the official website of the Federal Agency for technical regulation and Metrology on the Internet or in the annual information index «National standards» published as on January 1 of the current year, and the editions of the monthly information index «National standards» for the current year. If the reference standard is replaced (changed), when using this standard should be guided by replacing (amended) standard. If the reference standard is cancelled without replacement, then the situation in which the given link applies to the extent that does not affect this link.
3 Classification of coatings
3.1 Outer protective coating are classified according to design, purpose and the operating temperature.
3.2 Classification of coatings according to the construction, purpose and operation temperature are given in table 1.
Examples of symbols:
Pipe electrically welded steel pipes with diameter of 530 mm, a wall thickness of 10 mm made of steel of strength class K52, manufactured according to GOST 20295−85, with three-layer polyethylene coating of the normal execution according to GOST 31448−2012:
Pipe — 530х10 — K52 GOST 20295−85, coating 3ПЭ-N, GOST 31448−2012
Welded steel pipe spiral-welded with a diameter of 820 mm, a wall thickness of 12 mm of steel grade Ст3сп2 made by the group In GOST 8696−74, double-layer polypropylene coating of the normal execution according to GOST 31448−2012:
Pipe — 820x12 — Ст3сп2 — GOST 8696−74, coating 2PP-N, GOST 31448−2012
Pipe electrically welded steel pipes with diameter of 530 mm, wall thickness 5 mm made of steel of strength class K48, manufactured according to GOST 31447−2012, with three-layer polyethylene-coated special designs according to GOST 31448−2012:
Pipe — 530x5 — K48 GOST 31447−2012, coating 3ПЭ, GOST 31448−2012
Table 1
| Room coverage | Design of the coating (designation) |
Type of coating (symbol) | Appointment | Pipe diameter in mm | Operating temperature, °C |
| 1 | Three-layer polyethylene (3ПЭ) | Normal (N) | For underground pipelines laid in the climatic areas I, II, III and has a product temperature less than 60 °C |
114−1420 | From minus 40 to plus 60 |
| 2 | Three-layer polyethylene (3ПЭ) | Heat Resistant (T) | For underground pipelines laid in the climatic areas in IV or having a product temperature of 60 °C |
114−1420 | From minus 50 to plus 80 |
| 3 | Three-layer polyethylene (3ПЭ) | Special (S) | For sections of pipe laid by directional drilling, microtunnelling and pulling |
114−1420 | From minus 60 to plus 60 |
| 4 | Two-layer polyethylene (2ПЭ) | Normal (N) | For non-critical piping assignments |
114−820 | From minus 50 to plus 60 |
| 5 | Three-layer polypropylene (3ПП) |
Normal (N) | For underwater and underground pipelines | 114−1420 | From minus 10 to plus 80 |
| 6 | Three-layer polypropylene (3ПП) |
Hardy (M) | For the far North | 114−1420 | From minus 20 to plus 80 |
| 7 | Three-layer polypropylene (3ПП) | Special (S) | For sections of pipe laid by directional drilling, microtunnelling and pulling |
114−1420 | From minus 20 to plus 110 |
| 8 | Double-layer polypropylene (2PP) | Normal (N) | For pipelines of underground gasket with high temperature product |
114−820 | From minus 10 to plus 110 |
| 9 | Single layer epoxy (e) |
Normal (N) | For pipelines of underground gasket | 114−820 | From minus 20 to plus 80 |
* Climatic regions are shown in accordance with the sanitary norms and rules [1]. Note — it is permitted to use coatings of other types, if it is caused by the pipeline project, provided that the technical characteristics of the protective coating to be not less than the requirements of this standard to most similar type coatings. | |||||
4 Technical requirements
4.1 Requirements for pipes intended for coating
4.1.1 the Coating is applied to seamless and welded steel pipes with diameter from 114 to 1420 mm, meets the requirements of normative documents (ND).
4.1.2 Outer surface of the pipe is subjected to visual inspection to detect surface defects.
On the surface of the pipe should be free of cracks, dents, cavities, delaminations, and other defects, bringing the wall thickness beyond the maximum permissible value.
If you cannot eliminate the above defects, the pipes are rejected and shall not be further processed by cleaning and applying a protective coating.
4.1.3 Outer surface of the pipe must be cleaned of dirt, oil and salt contamination, and conservation cover (if available) with appropriate solvent or alkaline solutions, steam or open flame.
4.1.4 On the pipe surface, the salt content should be not more than 30 µg/cm
.
As the acceptable level of salt contamination should be considered as a negative value test ferrocyanide potassium in accordance with the methods of instrument control. In the case of excessive amounts of salts pipe surface should be washed with a solution of phosphoric acid or distilled (deionized) water.
4.1.5 recommended surface temperature of the pipe before carrying out shot-blasting (shot blasting) cleaning is from 50 °C to plus 70 °C.
4.1.6 surface of the pipe treated with the method of shot-blasting or shot blasting. The degree of cleanliness shall be Sa 2 ½ and surface roughness of 40−80 microns. After cleaning the surface of the pipe must be cleaned of dust.
Dust particles should have a diameter of less than 100 microns.
4.1.7 All external defects after cleaning should be removed.
Repaired areas with an area of more than 100 cmmust have a surface roughness in accordance with the requirement specified
4.1.8 Time between end of treatment and the beginning of the coating should not be more than 2 hours at a humidity of over 80% and 3 hours at a humidity of less than 80%. In case of failure of the above requirements, the mechanical treatment should be repeated.
4.1.9 To increase coating adhesion in addition to mechanical cleaning can be carried out chemical treatment (passivation) of the surface of the pipes chromate, phosphate or chromatopathia solutions.
4.1.10 When coating the surface temperature of the coated pipes shall conform to the requirements of the technological regulation of the developer coating.
4.2 material Requirements for the application of protective pipe coating
4.2.1 the Materials included in the coating composition should meet the regulatory requirements for these materials and to ensure that external coating of pipe in accordance with the requirements of this standard.
4.2.2 the Compliance properties of insulation materials the technical requirements nominees must be confirmed by the quality certificate and the input control of the enterprise, causing coating.
4.2.3 Labeling materials should include:
— name,
— stamp
— the batch number,
the date of production.
4.3 Requirements for protective coating of pipes
4.3.1 three-layer polyethylene coating shall consist of:
— the adhesion sublayer on the basis of epoxy powder and liquid paints; minimum dry film thickness: not less than 60 µm for powder coatings, 20 microns for liquid paints. Thickness agreed with the customer;
— adhesive sublayer based on hot-melt polymer compositions; minimum thickness: not less than 150 mm — powder when applied, not less than 200 µm when applied by extrusion;
— the outer layer is based on extruded polyethylene.
4.3.2 two-layer polyethylene coating shall consist of:
— adhesive sublayer based on hot-melt polymer compositions;
— outer layer-based termoventilatore polyethylene.
4.3.3 three-layer polypropylene coating shall consist of:
— the adhesion sublayer on the basis of epoxy powder and liquid paints; minimum dry film thickness: not less than 60 µm for powder coatings, 20 microns for liquid paint;
— adhesive sublayer based on hot-melt polymer compositions; minimum thickness: not less than 150 mm — powder when applied, not less than 200 µm when applied by extrusion;
— the outer layer is based on extruded polypropylene.
4.3.4 double-layer polypropylene coating shall consist of:
— adhesive sublayer based on hot-melt polymer composition; minimum thickness: not less than 150 mm — powder when applied, not less than 200 µm when applied by extrusion;
— the outer layer is based on extruded polypropylene.
4.3.5 single-layer epoxy coating consists of a single insulating layer.
4.3.6 the Thickness of the coatings depending on tube diameters and types of performance coatings shall conform to the requirements of table 2.
Table 2
In millimeters
| The number and kind of coverage | Minimum total coating thickness pipe diameter | |||
| from 114 to 273 incl. | St. 273 up to 530 incl. | St. 530 to 820 incl. |
St. 820 | |
| 1 three-layer polyethylene coating of the normal performance |
Of 2.00 | 2,20 | 2,50 | Of 3.00 |
| 2 three-layer polyethylene coating of the normal performance heat resistant | ||||
| 3 three-layer polyethylene coating of special design |
2,20 | 2,50 | Of 3.00 | 3,50 |
| 4 two-layer polyethylene coating of the normal performance |
Of 2.00 | 2,20 | 2,50 | - |
| 5 three-layer polypropylene coating of the normal performance |
1,80 | Of 2.00 | 2,20 | 2,50 |
| 6 three-layer polypropylene coating of the normal performance with a high resistance to frost | ||||
| 7 three-layer polypropylene coating special design |
Of 2.00 | 2,20 | 2,50 | Of 3.00 |
| 8 double-layer polypropylene coating of the normal performance | ||||
| 9 single layer epoxy coating normal performance |
0,35 | - | ||
| Notes 1 At the request of the customer minimum thickness of the coating normal and special performances can be increased. 2 the thickness of the coating special designs over the weld reinforcement shall be not less than 2 mm — for pipes up to 530 mm inclusive, not less than 2.5 mm — for pipes with diameter up to 820 mm inclusive, and not less than 3 mm — for tubes with a diameter of 820 mm. 3 coating Thickness of the normal performance over the weld reinforcement shall be not less than 1.7 mm — for pipes up to 530 mm inclusive, at least 2 mm — for pipes with diameter up to 820 mm inclusive, and not less than 2.5 mm — for pipes with a diameter of 820 mm. | ||||
4.3.7 the pipe Ends on the length of (140±40) mm from the end should be free from coating. At the request of the customer may increase or decrease in the length-free coating of pipe ends and the application of a protective conservation coating for the period of transportation and storage of insulated pipes.
4.3.8 the angle of the bevel of the coating to the pipe surface should be no more than 30°.
4.3.9 the Coating should have a uniform smooth surface without gaps and defects. Allowed the presence of small nodules — the local thickening (not more than 2 mm above the level of the main surface) and the «waviness» of the coating without bringing the coating thickness for the values given in table 2.
If there is a local non-through defects of the coating can be repaired.
4.3.10 Technical requirements for external coating of pipes are given in table 3.
Table 3 — specifications for the external coating
| Name of the indicator | The norm | Test method | Room coverage at the table 1 |
| 1 appearance | Homogeneous surface free of defects and omissions |
Visually | 1, 2, 3, 4, 5, 6, 7, 8, 9 |
| 2 Dielectric continuity, kV, no less | No breakdown cover at an electric voltage of 5 kV per 1 mm of coating thickness + 5 kV additionally. |
Using a spark flaw detector | 1, 2, 3, 4, 5, 6, 7, 8 |
| No breakdown cover at an electric voltage of 5 kV per 1 mm coating thickness |
9 | ||
| 3 strength of the coating upon impact, j/mm actual thickness, not less, at temperature: |
According to GOST 25812 (Annex A) | ||
| plus (20±5) °C: | |||
| for pipes with diameter up to 820 mm incl. | 5 | 1, 2, 4, 8, 3 | |
| 8 (full thickness) | 9 | ||
| 6 | 5, 6, 7 | ||
| for pipe diameters of St. 820 to 1420 mm | 6 | 1, 2, 3 | |
| 8 | 5, 6, 7 | ||
| plus (60±3) °C: | |||
| for pipes with diameter up to 820 mm incl. | 3 | 1, 2, 3, 4, 8 | |
| 6 | 5, 6, 7 | ||
| for pipe diameters of St. 820 to 1420 mm | 4 | 1, 2, 3 | |
| 6 | 5, 6, 7 | ||
| minus (10±2) °C |
5 | 5, 7, 8 | |
| minus (30±2) °C |
5 | 6 | |
| 4, the Adhesion of the coating to the steel after ageing in water for 1000 h at temperatures from plus (20±5) °C plus (80±3) °C, points, no more |
1 | According to GOST 15140 | 9 |
| 5, the Adhesion of the coating to steel at a test temperature: | |||
| plus (20±5) °C: | |||
| for pipes with diameter up to 820 mm, incl., N/cm, not less |
70 | According to GOST 411 (method A) | 4, 8 |
| 100 | 1 | ||
| 150 | 2, 3 | ||
| 200 | 5, 6, 7 | ||
| points, not more |
1 | According to GOST 15140 | 9 |
| for pipe diameters of St. 820 to 1420 mm, N/cm, not less |
100 | According to GOST 411 (method A) | 8 |
| 150 | 1 | ||
| 200 | 2, 3, 5, 6 | ||
| 250 | 7 | ||
| plus (60±3) °C: |
Application And | ||
| for pipes with diameter up to 820 mm, incl., N/cm, not less |
30 | 4, 8 | |
| 50 | 1, 3 | ||
| 75 | 2 | ||
| 100 | 5, 6 | ||
| 120 | 7 | ||
| for pipe diameters of St. 820 to 1420 mm, N/cm, not less |
50 | 8 | |
| 75 | 1, 3 | ||
| 100 | 2, 5, 6 | ||
| 120 | 7 | ||
| plus (80±3) °C: |
Application And | ||
| for pipes with diameter up to 820 mm, incl., N/cm, not less |
20 | 8 | |
| 50 | 2 | ||
| for pipe diameters of St. 820 to 1420 mm, N/cm, not less |
30 | 8 | |
| 75 | 2 | ||
| plus (110±2) °C: |
Application And | ||
| for pipes with diameter from 114 to 1420 mm, N/cm, not less |
50 | 5, 6 | |
| 60 | 7 | ||
| 6 Reduction in adhesion to steel, % of original value after 1000 hours of testing in water at a temperature not more than: |
In Appendix B | ||
| plus (20±5) °C |
30 | 1, 2, 3, 4, 5, 6, 7 | |
| plus (60±3) °C |
33 | 1, 2, 3, 4 | |
| 30 | 5, 6, 7 | ||
| plus (80±3) °C |
50 | 2 | |
| 30 | 5, 6, 7 | ||
7 the area of the cathodic flaking of the coating, see |
According to GOST 25812 (Appendix C) | ||
| plus (20±5) °C |
4 | 1, 2, 5, 6, 9 | |
| 3 | 3, 7 | ||
| 5 | 4, 8 | ||
| plus (60±3) °C |
10 | 1, 2, 5, 6 | |
| 7 | 3, 7 | ||
| 15 | 4, 8 | ||
| plus (80±3) °C |
15 | 2, 5, 6, 8 | |
| 10 | 7 | ||
8 contact resistance of the coating in 3% strength solution |
According to GOST 25812 (Annex G) | ||
| source plus (20±5) °C |
10 |
1, 2, 3, 4, 5, 6, 7, 8 | |
10 |
9 | ||
| after 100 days of exposure plus (20±5) °C |
10 |
1, 2, 3, 4, 5, 6, 7, 8 | |
10 |
9 | ||
| after 100 days of exposure plus (80±3) °C |
10 |
2, 5, 6, 7 | |
| 9 penetration (resistance to indentation), mm, not with temperature: |
According to GOST 25812 (Annex E) | ||
| plus (20±5) °C |
0,2 | 1, 4, 8 | |
| 0,15 | 2, 3 | ||
| 0,1 | 5, 6, 7, 9 | ||
| plus (60±3) °C |
0,3 | 1,4 | |
| 0,2 | 2, 3 | ||
| plus (80±3) °C |
0,4 | 2 | |
| 0,3 | 8 | ||
| plus (110±3) °C |
0,4 | 5 | |
| 0,3 | 6, 7 | ||
| 10 Resistance to cracking at a temperature of (50±3) °C, hour, not less |
1000 | According to GOST 13518 | 1, 2, 3, 4, 5, 6, 7, 8 |
| 11 Resistance to ultraviolet (UV) radiation flux 600 kWh/m at a temperature of (50±3) °C, hour, not less |
500 | According to GOST 16337 | 1, 2, 3, 4, 5, 6, 7, 8 |
| 12 of the Mould cover, points, not more | According to GOST 9.049 | 1, 2, 3, 4, 5, 6, 7, 8 | |
| 2 | According to GOST 9.050 | 9 | |
| 13 tensile Strength of the delaminated coatings, MPa, not less at a temperature of: |
According to GOST 11262 | ||
| plus (20±5) °C |
12 | 1, 2, 4, 8 | |
| 18 | 3 | ||
| 15 | 5, 6 | ||
| 20 | 7 | ||
| plus (60±3) °C |
10 | 1, 2, 4, 8 | |
| 15 | 3 | ||
| 14 elongation at tear delaminated coating, %, not less, at temperature: | |||
| plus (20±5) °C |
350 | According to GOST 11262 | 1, 2, 3, 5, 6, 7 |
| 200 | According to GOST 11262 | 4, 8 | |
| 5 | According to GOST 18299 | 9 | |
| minus (40±3) °C |
100 | According to GOST 11262 | 1, 2, 3, 4 |
| 15 Stability, % of the original values: | |||
| a) the change in the melt flow index of the delaminated coating when exposed to air at a temperature of: |
According to GOST 11645 | ||
| plus (110±3) °C, not more | |||
| for 100 days |
35 | 1, 3, 4 | |
| 25 | 2 | ||
| plus (150±3) °C, not more | |||
| over 1000 hours |
50 | 5, 6, 7 | |
| b) a reduction in elongation at break after aging in air at a temperature of: |
According to GOST 11262 | ||
| plus (110±3) °C, not more | |||
| over 1000 hours |
25 | 1, 3, 4, 5, 6, 7, 8 | |
| for 100 days |
25 | 2 | |
| 16 resistance of the coating to thermal Cycling, the number of cycles without delamination and cracking of the coating, not less, at temperature: |
The application In | ||
| from minus (50±3) °C to (20±5) °C |
Ten | 1, 2, 3, 4 | |
| from minus (20±2) °C to (20±5) °C |
10 | 5, 7, 8 | |
| from minus (60±3) °C to (20±5) °C |
10 | 9 | |
| from minus (40±2) °C to (20±5) °C |
10 | 6 |
5 safety Requirements
5.1 security Requirements for the application of protective coating on the pipe should correspond to GOST 12.3.002, GOST
5.2 during the chromate treatment of the surface of the pipe in the working zone air vapours and aerosols containing the active ions should not exceed the maximum permissible concentration (MPC) 0.05 mg/m
.
During application of epoxy primer in the polymerization process the concentration of harmful substances in the air (MPC) of the working area must not exceed:
— epichlorohydrin — 1 mg/m;
— formaldehyde — 0,5 mg/m;
— toluene — 50 mg/m;
— phenol is 0.3 mg/m.
In the process of drawing polyethylene and adhesive at temperatures above 150 °C the release of harmful substances (MPC) shall not exceed:
vinyl acetate and 10.0 mg/m;
acetic acid, 5.0 mg/m;
— acetaldehyde — 5.0 mg/m.
The concentration of harmful substances in the air of working zone shall not exceed their MPC according to GOST
5.3 application Works on the pipe protective coating shall be conducted in the premises, equipped with local and General exchange ventilation, providing clean air in accordance with the requirements of GOST
6 Requirements of environmental protection
6.1 Monitoring of compliance with maximum permissible emissions into the atmosphere during application of the protective coating must be exercised according to GOST
6.2 special events to prevent harm to the environment, health and genetic Fund of the person under test, storage, transportation and operation of pipes with protective coatings is not required.
7 acceptance Rules
7.1 a quality control inspection of pipes with an external coating is conducted by the office of technical control of the manufacturer.
Acceptance of coated pipes can be held by a user, as well as the specialized organization at the request of the consumer.
7.2 Pipe with external coating applied to the receiving parties. The party consists of pipes of the same size, made of steel of the same brand with the same external coating applied according to the established technology with the use of insulating materials of the same brand. The number of tubes in a batch must not exceed 100 pieces for pipe diameters up to 530 mm and 50 pieces for pipes of diameter over 530 mm.
7.3 each batch of coated pipes and transport unit issued a document on the quality according to GOST 10692, which shall include data on the quality of coating and insulation materials used.
7.4 quality Control of the coating for compliance with the requirements of this standard includes the following tests:
— control of compliance of insulation materials documents about the quality;
— acceptance;
— periodicals.
7.5 acceptance tests performed on each lot of insulated pipes. Tests include:
7.5.1 length Measurement-free coating of pipe ends (hold each tube).
7.5.2 measurement of the bevel angle of the coating to the surface of the pipe (hold at each end of each pipe).
7.5.3 quality assurance external coating of pipes, including:
control the appearance of the coating (performed on each tube);
— coating thickness measurement (conducted not less than 10% tube party);
— testing coating on the dielectric continuity (control subject the entire outer surface of the pipe, except the scatter from the coating end sections and chamfers; is carried out on each tube);
— determination of the strength of the coating upon impact at a temperature of (20±5) °C (conduct on at least two of the pipes from the party);
— determination of coating adhesion to the steel at a temperature of (20±5) °C (conduct on at least two of the pipes from the party).
7.5.4 Checking the markings on the pipe coating (performed on each tube).
7.6 In case of unsatisfactory results of acceptance testing of coating at least one of the indicators it is carried out re-tests on twice the number of tubes taken from the same batch. In case of unsatisfactory results, re-testing is allowed by the piece delivery of coated pipes with the control in terms with unsatisfactory results.
7.7 At the request of the customer, the volume of the acceptance tests can be increased.
7.8 Periodic testing carried out during the development of the technology of the factory coating of pipes, changing the brand of insulation materials, as well as changing basic parameters of the technological process specified by the manufacturers of materials and equipment, but not less than once per year. Periodic tests may be carried out also according to customer’s requirement.
7.9 Periodic tests include:
— determination of the strength of the coating upon impact at a temperature of minus (30±2) °C, minus (10±2) °C plus (60±3) °C;
— determination of coating adhesion to the steel at a temperature of (60±3) °C plus (80±3) °C and plus (110±2) °C;
— definition of reduce the adhesion of the coating to the steel after 1000 h of aging in water at a temperature of (20±5) °C, plus (60±3) °C plus (80±3) °C;
— determine the area of flaking of the coating during the cathodic polarization after 30 days of exposure in 3% strength solution at a temperature of (20±5) °C, plus (60±3) °C plus (80±3) °C;
— determining the transition resistance of the coating after 100 days of exposure in 3% strength solution at a temperature of (20±5) °C plus (80±3) °C;
— determination of resistance to penetration (indentation) of the coating at a temperature of (20±5) °C, plus (60±3) °C plus (80±3) °C, plus (110±3) °C;
— determination of the resistance of coating to cracking at a temperature of (50±3) °C;
— determination of the resistance of coatings to ultraviolet (UV) radiation flux 600 kWh/m at a temperature of (50±3) °C;
— determination of the resistance of the coating to fungal infections;
— determination of the strength at break of the delaminated coating at a temperature of (20±5) °C, plus (60±3) °C;
— determination of the elongation at break of the delaminated coating at a temperature of minus (40±3) °C, plus (20±5) °C;
— detection of changes of the melt flow index of the delaminated coating after exposure in air for 100 days at a temperature of (110±3) °C and for 1000 h at a temperature of (150±3) °C;
— definition of the reduction of the elongation at break of the delaminated coating after exposure in air at a temperature of (110±3) °C for 100 days and 1000 hours;
— determination of the resistance of coatings to thermal Cycling at a temperature of from minus (50±3) °C to (20±5) °C, from minus (60±3) °C to (20±5) °C, from minus (20±2) °C to (20±5) °C and from minus (40±2) °C to (20±5) °C.
7.10 Periodic tests carried out on specimens cut from pipes (at least three samples for each indicator properties of the coating or in accordance with the standard for test method).
Samples cut from two sections of the pipe (start and end) remote from the end face of the protective coating of not less than 100 mm. the Sampling carried out on two pipes from the party. In the manufacture of samples is not allowed the heating of the material samples to a temperature of over plus 80 °C.
7.11 If there are unsatisfactory results of the periodic tests cover repeat tests are carried out at twice the number of pipes, except the pipe does not stand the test. When you re obtaining negative results of the technological process of the factory coating of pipes must be suspended pending clarification and elimination of causes of non-compliance cover the requirements.
7.12 Pipe, which coverage does not meet the requirements of this standard, is rejected and sent for repair or re-coating.
8 Methods of control
8.1 surface appearance evaluated visually.
8.2 measuring the length of the uninsulated ends of the pipes is performed using a template or metal ruler according to GOST 427 with tolerance of ±1 mm.
8.3 the angle of the bevel of the coating is measured using a template-protractor made in the prescribed manner with an accuracy of ±1°.
8.4 the Thickness of the coating is determined by any thickness gauge designed for measuring the thickness of non-ferromagnetic coatings on ferromagnetic substrate with an accuracy of 0.1 mm. thickness Control is carried out in at least three sections, evenly spaced along the length of the pipe, and not less than four points of each section.
8.5 Testing a dielectric coating on the continuity of conduct spark flaw detector, constant current measurement error no more than 5%. The testing shall be the entire outer surface of the pipe with coating, with the exception of the non-insulated end sections and chamfers.
8.6 the strength of the coating at impact in the range of temperatures determined by the method described in GOST 25812 (Appendix A). Tests carried out on coated pipes or on samples from coated pipes. The recommended sample size — 200 x 100 mm.
When tested at a temperature different from room, the coated specimens are placed in termobarocamerr providing automatic maintenance of the set temperature. Samples are heated or cooled to temperatures above or below the test temperature is set to a device for determining the shock strength and conducting follow-up blow. Measuring the temperature of the sample is carried out using a digital contact thermometer (thermocouple) with a measurement accuracy of ±1 °C.
8.7 adhesion of the polyethylene or polypropylene coating to steel at a temperature of (20±5) °C, determined according to GOST 411 (test method A, the angle of peel is 90°).
The adhesion of the polyethylene or polypropylene coating to steel at a temperature of (60±3) °C plus (80±3) °C and plus (110±2) °C, determined according to the method of application A.
The adhesion of epoxy coating to steel at a temperature of (20±5) °C, determine the churchyard 15140.
8.8 the adhesion of the polyethylene or polypropylene coating to steel after 1000 hours of testing in water at a temperature of (20±5) °C, plus (60±3) °C plus (80±3) °C, determined on samples cut from coated pipes, according to the method of application B.
The adhesion of epoxy coatings to steel after 1000 hours of testing in water at a temperature of (20±5) °C plus (80±3) °C, determined on samples cut from the coated pipes, the graveyard 15140.
8.9 assessment of the robustness of the coating to cathodic disbondment is carried out in accordance with GOST 25812 (Appendix C). For testing select samples of pipes of size not less than 100x100 mm, without visible damage and tested for dielectric integrity of the spark detector at a voltage of 20 kV.
8.10 the contact resistance of the coating is determined in accordance with the method GOST 25812 (Appendix G). For testing select samples of a size not less than 100x100 mm, without visible damage and tested for dielectric integrity of the spark detector at a voltage of 20 kV.
For testing at a temperature of (20±5) °C plus (80±3) °C using an oven for maintaining a predetermined temperature with an accuracy of ±3 °C.
8.11 Resistance of the coating penetration (indentation) is determined by the method GOST 25812 (Appendix E). For tests using samples cut from coated pipes, size of 100x100 mm.
For testing at elevated temperature (60±3) °C plus (80±3) °C and plus (110±3) °C using an oven for maintaining a predetermined temperature with an accuracy of ±3 °C.
8.12 Resistance to cracking at a temperature of (50±3) °C determined by the method GOST 13518. For testing selected samples of the delaminated coating (without epoxy primer and adhesive sublayer) with the surface of the polyethylene or polypropylene layer that meets the requirements
8.13 Resistance to UV radiation flux of 600 kW·h/m at a temperature of (50±3) °C is estimated according to the method GOST 16337. For testing selected samples of the delaminated coating (without epoxy primer and adhesive sublayer) with the surface of the polyethylene or polypropylene layer that meets the requirements
The coating is considered to be satisfactory if the change in relative elongation at break of the delaminated coating after exposure in the chamber UV radiation for 500 hours does not exceed 25% of the original value.
Allowed evaluation of resistance of coatings to UV radiation to carry out according to GOST 11645. The coating is considered to be satisfactory if the change in the melt index of the coating after exposure in the chamber UV radiation for 500 hours does not exceed 35% of the original value.
8.14 Resistance of polyethylene and polypropylene coatings to fungal infections is determined according to the method 2 GOST 9.049. According to customer demand for pipelines, the operation of which is planned in a warm, humid climate (tropical zone), in which the environment contains a large number of active debate allowed the testing by method 3 GOST 9.049.
The durability of epoxy coatings to fungal lesions is determined according to GOST 9.050.
8.15 tensile Strength and elongation under tension of the delaminated polyethylene or polypropylene coating is determined in accordance with GOST 11262. The tests are carried out on a tensile testing machine with measurement error not more than 2%. For testing use samples in the form of «blade» — type 1 according to GOST 11262 with lengths of 33 mm and a width of 6 mm, made from delaminated (readhesion) coating using a standard knife.
For testing at temperatures different from room, use termobarocamerr providing automatic maintenance of the set temperature with an accuracy of ±3 °C. To normalize the temperature inside the working space of thermocryochamber must be equipped with a fan. Exposure of samples in the chamber at a predetermined temperature prior to testing shall not be less than 30 min.
The rate of stretching of samples: 100 mm/min when tested at a temperature of (20±5) °C and plus (60±3) °C, 50 mm/min at a temperature of minus (40±3) °C.
Elongation at break of the delaminated epoxy coating at a temperature of (20±5) °C, determined according to GOST 18299. The speed of tensile specimens of 2.5 mm/min.
8.16 Determination of thermal stability of the coating to change the melt flow index and change of elongation at break of the coating delaminated after thermostate in air at a temperature of (110±3) °C and plus (150±3) °C is carried out in accordance with GOST 11645 and GOST 11262.
To conduct tests to determine changes in the melt flow index of polyethylene or polypropylene selected samples of the delaminated coating (without epoxy primer and adhesive sublayer), which is placed in air thermostat maintained at a temperature of (110±3) °C for 100 days or 1000 hours (depending on the type of coating pipes), after which the test carried out according to the method GOST 11645.
To conduct tests to determine changes in relative elongation at break of the delaminated coating use samples of the delaminated coating (without epoxy primer and adhesive sublayer) in the form of «blades» type 1 according to GOST 11262. The samples aged for 100 days or 1000 hours (depending on the type of coating pipes) in an oven at a temperature of (110±3) °C, followed by tests to determine the elongation at break on a tensile testing machine at a speed of stretching of 100 mm/min.
8.17 resistance of the coating to thermal Cycling at a temperature testing from minus (50±3) °C to (20±5) °C, from minus (20±2) °C to (20±5) °C, from minus (60±3) °C to (20±5) °C and from minus (40±2) °C to (20±5) °C is estimated according to the method set out in Annex V.
9 Labelling, transportation and storage
9.1 marking applied to the outer or inner surface of the pipe coated in accordance with GOST 10692 and GOST 14192 at a distance of not more than 1000 mm and not less than 150 mm from the pipe end.
In addition to data on the uncoated pipe, provided corresponding LP, labeling contains:
is a trademark or enterprise name, causing the coating (if the pipe production and coating is carried out at different enterprises);
— designation of the coating;
— the designation of this standard;
— the batch number of the coated pipes;
— the date of coating application;
— the mark of the technical control of the product acceptance.
Marking can be performed with a stencil or printing resistant inks of contrasting color. Place marking shall if necessary be subjected to additional processing:
— surface treatment by corona discharge, flame or chemical treatment;
— the metal surface of the primer or subsequent paint.
Permitted by agreement with the customer to affix on self-adhesive labels which are pasted on the surface of the metal or coating. While personal identification number pipe should be applied to the surface of the coating or metal pipes by marking, resistant paint or permanent marker, guaranteed to ensure its safety.
For pipes with a diameter of 219 mm and less allowed the markings to put on the metal label to each package in the shipment of tubes in packages.
9.2 Packing
After coating on the pipe must be restored to their original packaging (protective flanges, protective caps or protection rings).
All the pipes with epoxy coating as packaging wear protective ring of rubber or synthetic rope. The thickness of the rings is at least 20 mm. the Number of rings must be at least three pipe diameters from 530 to 820 mm and not less than four pipe diameters less than 530 mm.
Packaging pipes with diameter of 325 mm and less into magazines or packages. Magazine design or package must ensure the safety coating of pipes.
Pipe with a three — or two-layer polyethylene and polypropylene coatings at the customer’s supply without additional packaging.
9.3 Pipes stored in the stacks. The bottom row of pipe should be laid on special pads covered with soft material or cushions of sifted sand, coated with a film of polymeric material.
Between the rows of pipes if necessary, place a strip of elastic material (a rubber plait, a rubber or rubber tape). Between spiral-welded pipes are required to establish the gaskets if the pipes have no packing in the form of elastic rings. When warehousing longitudinally welded pipes, the seam must be oriented in the gap between the pipes.
9.4 handling and storage of insulated pipes should be conducted in conditions that prevent mechanical damage to the coating. The use of steel ropes, slings that can lead to failure of the coating and damage of pipe ends is prohibited.
9.5 Transportation of insulated pipes shall be made by trucks equipped with special devices that exclude the movement of pipes and coating damage.
9.6 Storage must not lead to violation of continuity of coverage.
Pipes with polyethylene coating, which is planned more than 6 months should be protected from exposure to ultraviolet radiation with covers, canopies and other appropriate methods.
Tubes with polypropylene coating must be protected from UV radiation if they are storing more than 90 days.
For pipes with epoxy coating special measures for protection from ultraviolet radiation are required.
Annex a (mandatory). Method of determining coating adhesion to steel at various temperatures tests in the laboratory
Appendix A
(required)
A. 1 Purpose of the method
The method is intended for evaluating the adhesion of the factory protective coating to steel at the test temperature plus (60±3) °C plus (80±3) °C and plus (110±2) °C during the peeling of the coating at an angle of 90°±10°.
A. 2 Requirements for samples and accessories
A. 2.1 the Samples for testing are samples cut from coated pipes. The samples with the coating defects do not. The thickness and dielectric continuity of the coating on the test specimens shall conform to the requirements of this standard.
Recommended sizes of samples for testing (150−180)x (80−100) mm in accordance with figure A. 1 (the first dimension coincides with the direction of coating). The number of parallel samples for the specified test conditions shall not be less than three.
Figure A. 1 — example for determining the adhesion of a coating when the peel angle of 90°±10°
1 — cover; 2 — propyl; 3 — the main area of exfoliation; 4 — a sample of the peelable coating;5 — steel substrate
Figure A. 1 — example for determining the adhesion of a coating when the peel angle of 90°±10°
A. 2.2 For the tests using the following devices, materials, tools and equipment:
— breaking machine with the price of division of the meter not more than 0.1 N (kgf 0,01), providing a rate of movement of the gripper (10±1) mm/min;
— fixture (clamp in accordance with figure A. 2 or the other clamp providing the predetermined test conditions) for mounting the specimen in the grips of the machine, wherein the fixture is fixed to the capture machine, and a sample of the peelable coating to a movable terminal;
— cutting tools (special knife, double saw with two cutting elements at a distance of 20 mm);
— a heat chamber, automatically maintaining the required temperature with accuracy of ±3 °C;
— metal ruler according to GOST 427;
— ethyl alcohol according to GOST 17299.
Figure A. 2 — Clamp for fixing samples
1 — protective coating; 2 — metal substrate (sample pipe); 3 — clamps; 4 — hole for mounting the clamp to capture the bursting machine; 5 — mounting screw
Figure A. 2 — Clamp for fixing samples
A. 3 Preparation for testing
With the help of cutting tool coating perform the notches in accordance with figure A. 1. Cuts carried out over the entire thickness of the coating to the metal of a width not less than 1 mm. cutting Edges inspect and test for any signs of flaking of the coating. Testing allowed samples with no signs of flaking of the coating.
Prior to testing at the end portions of the samples peeled in three bands covering a width of 20 mm each length (30±5) mm. the Width of each break-away strip is measured using a metal ruler with an accuracy of ±1 mm.
A. 4 testing
The sample is placed in a heat chamber, which provides automatic maintenance of the set temperature with an accuracy of ±3 °C, and allowed to stand for 30 min.
Then the coated sample is inserted into the clamp in accordance with figure A. 2. The clamp is fixed in a stationary grip machine, and the free end of the delaminated strip in the movable grip, and then include the breaking machine, and is carried out the peeling of the coating from the steel at a speed of the movable gripper 10 mm/min.
A. 5 Handling of test results
The adhesion of the coating to steel , N/cm when the test temperature plus (60±3) °C plus (80±3) °C and plus (110±2) °C during the peeling of the coating at an angle of 90°±10° at each sample is calculated by the formula
where the adhesion of the coating to the steel
-th sample, N/cm;
the average peel force, N (determined by the middle line on the chart or as the arithmetic mean value of the efforts of exfoliation);
— the average width of strips, cm (defined as the arithmetic mean value of the results of the three measurements).
The test results of the parallel samples is calculated by the formula
where the adhesion of the coating to the steel
-th sample, N/cm;
— the number of samples.
________________
* Formula conforms to the original. — Note the manufacturer’s database.
When processing test results for the rate of adhesion of the coating to steel take the average value of the rate of adhesion of the coating to the steel, obtained for three parallel measurements.
