Some standard content:
ICS25.220.60
National Standard of the People's Republic of China
GB/T 18593—2001
Anti-corrosive painting of fusion bonded epoxy coating powders2001-12-17 Issued
People's Republic of China
General Administration of Quality Supervision, Inspection and Quarantine
2002-06-01 Implementation
GB/T18593—2001
Cited Standards
Technical requirements that the purchaser should provide to the supplier
Coating classification
Process specification
Repair of fusion bonded epoxy coating
Performance requirements and test methods of fusion bonded epoxy coating 10 Inspection rules
Appendix A (Appendix to the standard)
Determination of the density of powder coatings by liquid displacement hydrometer method Appendix B (Appendix to the standard)
Appendix C (Appendix to the standard)
Appendix D (Appendix to the standard)
Supplementary explanation of coating impact resistance test (normal temperature test) Supplementary explanation of coating bending resistance test (normal temperature test), specified media and conditions for coating chemical corrosion resistance test GB/T18593—2001
Appendix A, B, C and D of this standard are all appendices to the standard. This standard is proposed by China Machinery Industry Federation. This standard is under the jurisdiction of the National Technical Committee for Standardization of Metal and Non-metallic Coverings. The responsible drafting unit of this standard: National Metal Corrosion Control Engineering Technology Research Center. Participating drafting units of this standard: China Petroleum Pipeline Technology Research Center, Institute of Building Structures, China Academy of Building Research. The main drafters of this standard: Zhang Lixin, He Zhiduan, Du Xiuling, Shi Zhihua, Li Jing, Li Xiaodong, Lu Weizhong. National Standard of the People's Republic of China
Anti-corrosive painting of fusion bonded epoxy coating powders1 Scope
GB/T18593—2001
This standard specifies the materials, process specifications, coating performance requirements and test methods for anti-corrosion coating of fusion bonded epoxy powder coatings for steel materials.
This standard does not apply to decorative coatings.
When this standard is applied to the coating of pipelines or structural parts in contact with food, the coating must comply with the provisions of GB9686 Hygienic Standard for Polyamide Epoxy Resin Coatings for the Inner Wall of Food Containers. 2 Cited Standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards are subject to revision, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T1408.1-1999 Test method for electrical strength of solid insulating materials Test under power frequency (eqvIEC60243-1:1988) GB/T1410—1989 Test method for volume resistivity and surface resistivity of solid insulating materials (eqvIEC93:1980) GB/T1713—1989
GB/T1771—1991
GB/T6329-1996
GB /T6554-1986
GB/T6682—1992
GB/T8923—1988
Determination of pigment density Pycnometer method (eqvISO787-10:1981)Determination of neutral salt spray resistance of paints and varnishes (egvISO7253:1984)Determination of tensile strength of adhesive butt joints (egvISO6922:1987)Test method for electrical insulating powder coatings (egvISO6922:1987) IEC60455-2-2: 1984) Specifications and test methods for water used in analytical laboratories (negISO3696: 1987) Rust grade and rust removal grade of steel surfaces before painting (eqyISO8501-1: 1988) GB9686-1988
8 Hygienic standard for polyamide epoxy resin coatings for the inner wall of food containers GB/T16592--1996
Determination of mass loss of powder coatings during baking (egvISO 8130-7:1992) GB/T16995--1997
Determination of gel time of thermosetting powder coating at a given temperature (eqvISO8130-6:1992) GB50152-1992 Standard for test methods of concrete structures JG3042--1997 Epoxy resin coated steel bars SY/T0315-1997 Technical standard for fusion bonded epoxy powder external coating of steel pipes 3 Definitions
This standard adopts the following definitions.
3.1 Fusion bonded epoxy coating powder Thermosetting fusion bonded powder coating with epoxy resin as the main film-forming material is also called "fusion bonded epoxy powder coating", referred to as "epoxy powder" in this standard.
3.2 Fusion bonded epoxy coating (layer) The film formed by curing epoxy powder coating through fusion bonding coating process, referred to as "fusion bonded epoxy coating" in this standard. Approved by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China on December 17, 2001 and implemented on June 1, 2002
GB/T18593-2001
3.3 Coated steel bar Fusion bonded epoxy painted steel bar Steel bar coated with fusion bonded epoxy powder coating. 3.4 Process pipes and fittings Processing pipes and fittings Pipes designed according to production process requirements, such as straight pipes, elbows, tees, reducers and other pipes of various shapes. 4 Technical requirements that the buyer should provide to the supplier
4.1 This standard number and name.
4.2 The grade, specification and surface state of the base steel and cast iron. 4.3 The thickness of the coating.
4.4 Sampling and inspection.
4.5 Application environment or medium conditions of coating products. 4.6 Select the type of coating (type 1, 2 or 3) and coating process. 4.7 Packaging of coating products.
5 Classification of coatings
5.1 Type 1 coatings
5.1.1 Anti-corrosion coatings for the outer wall of buried steel pipelines. 5.1.2 Anti-corrosion coatings for the inner wall of pipelines transporting oil, natural gas, fresh water or seawater. 5.2 Type 2 coatings
Anti-corrosion coatings for steel bars.
5.3 Type 3 coatings
5.3.1 Protective coatings for steel or cast iron process pipelines working in severe corrosion environments. 5.3.2 Protective coatings for steel or cast iron structural parts working in severe corrosion environments. 6 MaterialsbZxz.net
6.1 Iron and steel substrates
6.1.1 Each batch of iron and steel substrates to be painted shall have relevant material, manufacturing and specification certification documents that meet national standards or user requirements. 6.1.2 Each batch of iron and steel substrates to be painted shall be inspected for appearance and size piece by piece (batch), and parts that do not meet manufacturing standards or contract requirements shall be removed.
6.2 Fusion-bonded epoxy powder coatings
6.2.1 Fusion-bonded epoxy powder coatings should be thermosetting powders containing epoxy resins and curing agents, pigments, and fillers. 6.2.2 Epoxy powders shall have the manufacturer's product manual, factory inspection certificate, and relevant quality assessment technical documents. 6.2.3 Epoxy powders used for coating food-contact pipes and structural parts shall have food hygiene certificates, and their coatings must comply with the provisions of GB9686.
6.2.4 The label of each batch of epoxy powder products should indicate: manufacturer name, product model, batch number, weight, production date, storage conditions, and storage period.
6.2.5 The coating plant or workshop should store powder coatings in accordance with the conditions specified by the coating manufacturer. 6.2.6 The performance of epoxy powder used for spraying various products should meet the technical indicators listed in Table 1. Before spraying, each batch of epoxy powder coatings should be tested in the laboratory according to the items in Table 1. Only those that meet the acceptance quality requirements can be used. 6.3 Repair materials
Repair materials should be two-component coatings based on epoxy resin or modified epoxy resin or other materials that are compatible with the original coating and have equivalent performance.
Density\
Volatile matter
Test items
Particle size distribution, particle size>150μm
Gel time
GB/T18593-2001
Table 1 Technical indicators of fusion-bonded epoxy powder coatings Unit
Technical indicators
Uniform, no agglomeration
Class 1 coating
90(180C)
30230C)
1) The density value of epoxy powder for special purposes should be controlled within ±20% of the value provided by the manufacturer. 7 Process Specifications
7.1 Surface treatment of steel substrates
Type 2 coating
Values provided by manufacturers
Test standards
Appendix A (Appendix to the standard)
GB/T16592
GB/T6554
GB/T16995
7.1.1 Before coating, the edges and corners of the surface of the parts to be coated should be ground into a fillet of R ≥ 2mm. The welds should be free of sharp corners, lack of meat, pores, cracks, gaps and welding slag. The defects and flaws on the surface of the parts to be coated that are prone to cause pinholes and uneven coating thickness should be removed. 7.1.2 Cast iron parts to be coated must be pre-heated and baked (about 300°C) for a sufficient time to ensure that the moisture and other volatiles remaining in the tiny gaps and defects on the castings are fully removed. 7.1.3 Before coating, the dust, oil, grease and other pollutants on the surface of the parts to be coated must be cleaned by appropriate methods. 7.1.4 According to GB/T8923, the surface of the parts to be coated shall be sandblasted or shot blasted to remove rust, so that it can reach the range of Sa240~100μm.
7.1.5 Visually inspect the parts to be coated again and eliminate the defects and flaws found. 7.1.6 Use purified compressed air or a metal brush to remove the residues remaining on the surface of the substrate due to the above process. Grade standard, the anchor pattern depth should be
7.1.7 The surface of the purified steel bar should be inspected in accordance with the requirements of Appendix A of JG3042-1997. No vapors shall be attached to the surface, and the cleanliness shall not be less than 95% before Class 2 coating can be applied. 7.1.8 Cover and protect the parts to be coated that do not need to be coated. 7.1.9 After the surface treatment of the parts to be painted, they must be painted within 3 to 8 hours. No visible rust should appear on the surface of the parts to be painted before double painting, otherwise the surface treatment should be repeated. 7.2 Preheating
7.2.1 The parts to be painted can be preheated in different ways, such as heating by a heating furnace or a continuous induction coil. 7.2.2 The preheating temperature is determined according to the temperature recommended by each powder coating manufacturer, but it shall not exceed 275C. 7.2.3 If the surface of the workpiece appears dark blue or dark brown due to over-oxidation caused by excessive temperature or long preheating time, the surface treatment should be repeated.
7.3 Coating
7.3.1 Coating can be carried out by electrostatic spraying, friction electrostatic spraying, fluidized bed, electrostatic fluidized bed, etc., to ensure that the coating reaches the required thickness and uniformity.
7.3.2 Use an oil-free air compressor and equip it with an air dryer to ensure that the compressed air for powder supply is oil-free and water-free. 7.3.3 Coating should generally be completed in one operation. When the third type of coating needs to be re-coated under special circumstances, it should be carried out before the previous coating is completely cured.
7.4 Curing of coating
7.4.1 The curing of the first and second types of coatings is completed by using the residual heat of the preheated substrate. If there is no special need, no additional heating and curing is required. 7.4.2 The third type of coating needs to be heated and cured again after coating. The specific curing temperature and time shall be carried out according to the conditions recommended by the epoxy powder coating manufacturer.
8 Repair of fused epoxy coating
GB/T18593—2001
8.1 If a few pinholes (1 to 2/m*) or unqualified areas with an area of less than 25cm2 appear locally in the first-class coating, local repair is allowed; if the defect area of the second-class coating does not exceed 1% of the surface area of the 0.3m long steel bar, repair is allowed; if pinholes appear locally in the third-class coating, the coating with pinholes should be removed and re-coated according to the coating process in Chapter 7. 8.2 Before repairing or re-coating, all oil, rust, and impurities must be removed, loose coatings must be peeled off, and the area must be polished into a rough surface. The joint between the repair layer and the surrounding intact coating should be polished into a wing shape, and then the surface should be cleaned. 8.3 The repair agent can be a two-component polymer composite coating or a two-component epoxy resin coating that can be closely bonded to the original coating. 8.4 The coating thickness of the repaired area shall be 1.5 times that of the original coating, and the overlap width with the original coating shall not be less than 10mm. Performance requirements and test methods of fusion-bonded epoxy coatings 9
9.1 The coating thickness shall comply with the requirements of the engineering design. If there is no requirement in the design, it can be selected according to the requirements of Table 2 based on the coating use conditions. Table 2 Coating thickness
Coating type
Category 1
Category 2
Category 3
Coating grade
Ordinary grade
Reinforced grade
Ordinary grade
Reinforced grade
Extra strong grade
Minimum thickness
Note: The requirements for coating thickness do not include the area where the coating is repaired due to coating defects or damage. 9.2 Physical properties of coating
Reference thickness
300~400
400500
130~300
300~600
600~1000
1000~1500
9.2.1 Before coating construction, the coating performance test should be carried out in the laboratory. Its physical properties should meet the requirements of Table 3. The provisions for specimen preparation are shown in 9.2.2.
Physical performance indicators of coating
Test items
Impact resistance (Emperor temperature)
Impact resistance (-30C)
Bending resistance (3°, room temperature)
Bending resistance (3°-30℃)
Bending resistance (room temperature)
Abrasion resistance (sand falling method)
Adhesion (prying method)
Bond strength
Bond strength (coated steel bar and concrete) Concrete
between)
Cathode stripping (24 or 48h)
Category 1
Performance index
Category 2
Smooth, uniform color, no bubbles
1~2No cracks
No cracks
≥80% of the
bonding strength between bare steel bars and concrete
Category 3
Standard test method
Appendix B (Standard Appendix Appendix C (Appendix to the standard)
SY/T0315
JG3042
SY/T0315
SY/T0315
GB/T6329
GB50152
SY/T0315
Cathode peeling
Electrical strength
Test items|| tt||Volume resistivity
Cross-sectional porosity
Interface porosity
GB/T18593-2001
Table 3 (end)
Performance index
Category 1
>1×101s
9.2.2 The preparation of laboratory coating specimens shall comply with the following provisions:Category 2
9.2.2.1 The specimen substrate shall be low carbon steel or the same substrate as the piece to be coated.Category 3
9.2.2.2 The surface of the specimen shall be sandblasted, and the rust removal quality shall reach Sa240~100μm according to GB/T8923.
9.2.2.3 The temperature for substrate preheating and coating curing shall be selected according to the recommended values of the epoxy powder manufacturer. Standard test method
JG3042
GB/T1408.1
GB/T1410
SY/T0315
SY/T0315
Grade. Anchor depth should be
9.2.2.4 Thickness of test piece coating: 350um±50μm for Class 1 and Class 3 coatings: 250μm±50μm for Class 2 coatings
9.2.2.5 Tests on laboratory painted test pieces should comply with the provisions of Table 3. 9.2.2.6 After curing, the painted test pieces should be placed at 23℃±5C or room temperature for 24h before performance testing can be carried out according to the operating steps in each test method.
9.3 Chemical corrosion resistance of coating
9.3.1 The test methods for chemical corrosion resistance of various coatings shall be carried out in accordance with GB/T6554. It is required that no peeling, cracking, softening, powdering or deterioration occurs in a specified medium at a certain temperature and time. The specified medium and conditions are listed in Appendix D (Appendix to the standard) or in accordance with the provisions agreed upon by the supply and demand parties.
10 Inspection rules
10.1 The appearance of the coating is visually inspected piece by piece (batch). The surface is required to be flat, uniform in color, free of bubbles, cracks, shrinkage cavities, and slight orange peel patterns are allowed.
10.2 The thickness of the coating is measured by a coating thickness gauge. 10.2.1 Class 1 coating: Randomly select 3 positions along the length of the pipe, and measure the coating thickness of 4 points evenly distributed around the circumference at each position; the measurement results shall comply with the provisions of 9.1. 10.2.2 Type 2 coating: The thickness shall be measured on opposite sides of the steel bar. Each thickness record value shall be the average of the thickness values of three adjacent auxiliary spaces. At least five points with roughly uniform intervals shall be taken along the entire 12m long steel bar for measurement. Except for the coating on the surface of the 100mm length at both ends of the steel bar, no less than 90% of the thickness records shall be within the range of 150-300μm, and no thickness record value lower than 130μm shall be allowed. 10.2.3 Type 3 coating: The thickness shall be tested at no less than 25 points per square meter, and the measurement results shall comply with the provisions of 9.1. 10.3 Leakage point (micropore) inspection shall be carried out by electric spark leak detector, and the coating surface temperature shall be lower than 100C during the inspection. 10.3.1 The detection voltage of Type 1 coating is 5V/μm, and the average number of leakage points per square meter shall not exceed 1. If exceeded, it shall be repaired or removed in accordance with the provisions of Chapter 8.
10.3.2 The second type of coating is tested with a voltage of 67.5V, and the average number of micropores per meter should not exceed 5. 10.3.3 The test voltage of the third type of coating is 5V/um. When leakage occurs, it shall be repaired or re-coated according to the provisions of Chapter 8. 10.4 Before leaving the factory, the first type of coating shall be sampled for impact resistance test, bending resistance test, cathode stripping and adhesion test, and can only be shipped if it meets the provisions of 9.2.1.
10.5 Before leaving the factory, the second type of coating shall be sampled for bending resistance test, and can only be shipped if it meets the provisions of 9.2.1. 10.6 Before leaving the factory, the third type of coating shall be sampled for impact resistance test and adhesion test, and can only be shipped if it meets the provisions of 9.2.1. 5
GB/T18593—2001
Appendix A
(Appendix of the standard)
Determination of density of powder coatings by liquid displacement hydrometer method This Appendix A is not equivalent to ISO8130-3:1992 "Determination of density by liquid displacement hydrometer method". A1 Principle
The density of powder coatings is determined by liquid displacement hydrometer method. The liquid used should be able to completely wet the sample and not cause the sample to swell or dissolve.
A2 Instrument
A2.1 The specific gravity bottle should comply with the provisions of GB/T1713. A2.2 The vacuum pump is connected with a rubber pressure-resistant pipe accessory. A2.3 The maximum weighing capacity of the balance is 200g, and the accuracy is 1mg or higher. A3 Materials
A3.1 The technical indicators of newly distilled and cooled water should at least comply with the third-grade purity specified in GB/T6682. A3.2 The displacement liquid is an aliphatic hydrocarbon or a mixture of aliphatic hydrocarbons that does not contain aromatic compounds and has a boiling point in the range of 8140°C. In many cases, n-heptane has been found to be suitable for determining the density of thermosetting powder coatings. However, if n-heptane can react with the sample or one of its components, other suitable liquids may be used.
A3.3 Acetone of analytical grade.
A4 Operating steps
Carry out two repeated measurements at 23°C ± 0.5°C, with a weighing accuracy of 1 mg. A4.1 Determination of the density of the displacement liquid
First weigh a clean empty pycnometer (A2.1), fill it to the scale with the displacement liquid, weigh it again, empty the pycnometer, clean it with acetone three times, dry it in a vacuum, pour water into the pycnometer again, and weigh it again. Calculate the density of the replacement solution at 23°C using the following formula: p (g/mL) Pr
Where: m—the mass of an empty pycnometer, g; ml—the mass of a pycnometer filled with replacement solution, g; mi-mo
m2—the mass of a pycnometer filled with water·g;
P—the density of water (under the conditions of this method, the density of water at 23°C, i.e., 0.998 g/mL, can be used). A4.2 Determination of the density of powder coatings
Empty the pycnometer, clean it three times with acetone, and dry it under vacuum. Place 3 to 4 g of the sample in the pycnometer and weigh it. Add enough replacement solution to just cover the sample to wet the sample, and connect the outlet of the pycnometer to the pressure-resistant pipe of the vacuum pump (A2.2). Depressurize the pycnometer to a minimum of 1.2 kPa, vibrating it until no more gas comes out of the powder/liquid mixture. Carefully raise the pressure in the pycnometer to atmospheric pressure, then fill the pycnometer to the mark with the replacement fluid. Do not stir the precipitated powder. Be careful to prevent the powder from sticking to the neck of the pycnometer when filling. Reweigh the fully loaded pycnometer. 6
A5 Expression of results
A5.1 Calculation
GB/T18593—2001
Calculate the density of the powder coating at 23°C P (g/mL) mg-mo
Pp= (m-mo) -
Where: ma - mass of the pycnometer plus the sample, g; m
- mass of the pycnometer plus the sample and the replacement fluid, g, xe
If the error between the two measurements is greater than 0.04 g/mL, the determination should be repeated (A4.2). Calculate the average of two valid determinations and report the result with an accuracy of 0.01 g/mL.
A5.2 Accuracy
Currently, there is little data on accuracy, and the error range of repeated tests can be set at 0.05 g/mL. A6 Test Report
The test report should at least include the following: a) All necessary specific identification of the product being tested; b) Test method;
c) Type of specific gravity bottle and replacement fluid used; d) Test results (data and average value for each test); e) Changes to the terms in this method;
f) Test date.
Appendix B
(Appendix to the standard)
Coating impact resistance test (normal temperature test) Supplementary explanation The equipment, test pieces and test report content required for the coating impact resistance test at normal temperature are the same as those specified in Appendix G of China's petroleum and natural gas industry standard SY/T0315. Only the test steps are carried out according to the following provisions: a) The cured coated specimen is placed in the impact test machine for more than 24 hours, and the stand block is aligned. b) The specimen is impacted 3 times according to the normal temperature impact strength value specified in Table 3 of 9.2.1. The distance between each impact point is at least 50mm, and the distance between the impact point and the edge of the specimen is at least 38mm. The spherical punch should be turned to an unused position after being used for a maximum of 10 times. The punch should be replaced after the total number of times reaches 200.
c) Use an electric spark leak detector to check the pinholes of the specimen. The voltage used should be adjusted to 1750V ± 250V. Appendix C
(Appendix to the standard)
Coating bending resistance test (normal temperature test) Supplementary explanation The equipment, specimens and test report content required for the bending resistance test of Class 3 coating at normal temperature are the same as those specified in Appendix F of China Petroleum and Natural Gas Industry Standard SY/T0315. However, the test steps are as follows: a) The coating edge should be smooth to eliminate any potential stress riser points. The cured coated specimen is placed at room temperature for more than 24 hours before testing.
b) Place the specimen on a flat surface and measure the specimen thickness (t), which is the sum of the steel pipe wall thickness and the inner arc chord height of the specimen. GB/T18593—2001
c) Use the following formula to calculate the mandrel radius, which corresponds to the bending length of the unit pipe diameter of 2.5° or 3° angle: degree of bending
Where: R——radius of mandrel, mm;
radius of mandrel
tthickness of specimen, mm.
d) Place the specimen on the mandrel of the selected radius of curvature for bending test. The bending rate should ensure that the whole process is completed within 10s. e) Visually inspect the specimen for cracks.
Appendix D
(Appendix of standard)
Specified media and conditions for chemical corrosion resistance test of coatings Table D1
Steamed stuffing water
Dilute hydrochloric acid
Sodium hydroxide solution
Sodium fluoride solution
Sodium hydroxide solution
10% sodium fluoride plus dilute sulfuric acid
Equivalent peptides Magnesium carbonate and calcium carbonate solution
Distilled water
Calcium chloride solution
Sodium hydroxide solution Liquid
Oxygen calcium oxide solution
Specified media and conditions for the first type of coating test Concentration, %
Temperature, c
Specified media and conditions for the second type of coating test Concentration, %
Temperature, C
Time, d
Time, d
The second type of coating must also undergo chloride penetration resistance test (JG3042) and salt spray resistance test (GB/T1771). In addition to the tests according to the media and conditions specified in Table D1, the third type of coating must also undergo the tests of various media and conditions listed in Table D3. The coating can only leave the factory if it does not fall off, crack, soften or deteriorate. Table D3 Specified media and conditions for test of type 3 coating (supplementary part) Medium
Sodium chloride solution
Sodium hydroxide solution
Concentration, %
Time, d
GB/T18593-2001
National Standard of the People's Republic of China
Anti-corrosion coating of fusion-bonded epoxy powder coatings GB/T18593--2001
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