This standard specifies an experimental method for measuring the shear strength of the bond between the pipeline anti-corrosion layer and the metal. This standard is applicable to the determination of the shear strength of the bond between the pipeline anti-corrosion layer and the metal through the experiment of the standard single-sided overlap test piece under the specified preparation and experimental conditions. SY/T 0041-1997 Test method for shear strength of the bond between the pipeline anti-corrosion layer and the metal SY/T0041-1997 Standard download decompression password: www.bzxz.net

1 Scope
Petroleum and Natural Gas Industry Standard of the People's Republic of China
Shear Strength Test Method for Bonding of Pipeline Anticorrosion Coating to Metal
Approval Department: China National Petroleum Corporation Approval Date: 1997-12-31
Implementation Date: 1998-07-01
SY/T0041—1997
Replaces SYJ41---1989
This standard specifies a test method for measuring the shear strength of bonding between pipeline anticorrosion coating and metal. This standard is applicable to the determination of the shear strength of bonding between pipeline anticorrosion coating and metal by testing standard single-sided overlapped specimens under specified preparation and test conditions. 2 Referenced Standards
The provisions contained in the following standards constitute the provisions of this standard by 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/T700—1988 Carbon structural steel
GB/T2517-1981 Hot-rolled steel plates and strips for general structures JJG139-1991 Tensile, pressure and universal testing machines JJG157-1995 Non-metallic tensile, pressure and universal testing machines 3 Significance and purpose
3.1 This test method is relative. This test method can be used to determine the quality of the bonding surface treatment and the endurance after bonding. It can also be used to control the surface treatment, coating and bonding process to determine the strength performance of the tested system. 3.2 The strength value obtained from this test method cannot be used as the design allowable stress value of the structural joint, otherwise it may cause failure. 3.3 Even on small specimens, short-term environmental changes can cause changes in the internal stress and chemical properties of the anti-corrosion layer. And this change will affect the bonding strength of the anti-corrosion layer.
3.4 ​​This test method can be used to compare and select the sensitivity of the anti-corrosion layer or bonding process to fatigue and environmental changes. However, such comparisons should be made with caution, because different anti-corrosion layers may react differently in different joints. 3.5 The accuracy of the shear strength test results of the anti-corrosion layer and metal depends on the bonding process. Unless otherwise agreed by the supply and demand parties, the bonding process will be formulated by the anti-corrosion coating manufacturer. To ensure the completeness of the data guiding the test, the anti-corrosion coating manufacturer shall provide the parameters and data required for the test in accordance with Appendix A (Appendix to the standard). bzxZ.net
4 Equipment
4.1 The testing machine used in this test method shall comply with the requirements of the JJG157 or JJG139 testing machine verification regulations. At the same time, it must be regularly verified by the national metrology department.
4.2 Selection of testing machine: Make the specimen failure load between 15% and 85% of the full scale, and the indication error of the testing machine shall not exceed 1%; the testing machine fixture shall be able to maintain a constant speed of less than 10mm/min without load; the testing machine shall have a fixture that can be used to clamp the specimen, and the tooth plates of the upper and lower fixtures can firmly engage the specimen at each end by 25mm. 4.3 The clamps of the testing machine shall be in the same straight line to ensure that the tensile axis of the specimen is consistent with the center line of the clamp. 872
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4.4 The length of the specimen clamped can be changed as needed, but for all specimens, the distance from the end of the bonding part to the end of the clamp shall be 63mml.
5 Specimens
5.1 The specimens shall conform to the shape and size shown in Figure 1 and shall be prepared in accordance with the provisions of Chapter 6. The specimens are recommended to be 1.60mm±0.16mm thick steel plates in accordance with GB/T2517, and the overlap length is recommended to be 15.0mm±0.5mm. Unit: mm
Clamping area
Bonding area
Figure 1 Shape and size of specimens
Clamping area
5.2 In the tensile test, the metal tensile stress shall not exceed the service value of the test plate material. Therefore, the overlap length of the specimen will vary with the metal used, the thickness of the specimen, and the properties of the anti-corrosion layer. Based on the study of the strength of the anti-corrosion layer, the maximum allowable length of the overlap portion can be determined by formula (1).
Where: Lnax—lap length (mm); t-metal plate thickness (mm);
Fty·t
Fi—metal yield stress (or metal proportional limit stress) (MPa); t-150% of the estimated average bond shear strength of the anti-corrosion layer (MPa). (1)
5.3 Changes in metal test plate thickness and overlap length will affect the test values ​​and make direct comparison of values ​​unreliable. Therefore, in all tests, the test plate thickness can be 1.60mm±0.16mm, the overlap length can be 15.0mm±0.5mm, or not more than the value determined in Section 5.2. For research tests, this value can be different, but should be kept as constant as possible. 5.4 The recommended test plate material should comply with the provisions of Q235 hot-rolled steel plate in GB/T700. 5.5 The number of test pieces should not be less than 30, but the number of test pieces can be reduced when statistical analysis of data and deviations is performed. 6 Test piece preparation
6.1 Cut the steel plate into test plates of the required size according to the requirements of 5.1 and Figure 1. Before surface pretreatment and bonding, the three edges of the test plate within the lap joint range should be machined and polished. 6.2 The lap surface of the test plate should be surface pretreated. The anti-corrosion coating is prepared according to the method recommended by the manufacturer and then applied to the lap surface at the end of the test plate. The coating length should be 6mm longer than the specified lap length. Overlap the metal test plates so that the two test plates are firmly bonded together. According to 5.3, the error of the lap length should be controlled within the range of ±0.5mm. When overlapping, the sides of the two test plates should be parallel and aligned. Cure or harden the anti-corrosion layer according to the conditions specified by the anti-corrosion coating manufacturer. 6.3 After the specimen is cured or hardened, trim the excess coating on the edge of the bonding surface, measure the overlap length and width of the specimen to an accuracy of 0.1mm, and measure the thickness of the anti-corrosion layer. The average thickness should not exceed 0.25mm, accurate to 0.01mm. 873
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7 Test steps
7.1 After the specimen is prepared in accordance with the provisions of Chapter 6, the test should be carried out as soon as possible, but the state adjustment procedure stipulated by the anti-corrosion coating manufacturer before the test should be met.
7.2 Select the force measuring plate of the testing machine and adjust the speed of the fixture for no-load operation. 7.3 Clamp the specimen in the fixture of the testing machine. The upper and lower fixture teeth clamp the specimen with a length of 25mm, and make the long axis of the specimen coincide with the center line of the fixture loading. Load the specimen at a selected loading speed and continuously load until the specimen is destroyed: 7.4 Record the failure load and failure characteristics of each specimen (the percentage of the total overlap area occupied by the cohesive failure of the anti-corrosion coating and the failure of the bond with the metal).
8 Calculation
8.1 The shear strength of each specimen is calculated according to formula (2) (the calculation is accurate to 0.01MPa). F
Shear strength of the anti-corrosion layer bonding (MPa); where: t—-
F-load of specimen destruction (N)
b---—width of the specimen bonding surface (mm); L---length of the specimen overlap surface (mm). (2)
8.2 Calculate the arithmetic mean of the shear strength of each group of test specimens, and determine the valid test specimens within the deviation range of ±15%. The number of valid test specimens should not be less than 60% of the original number, otherwise the test should be repeated. Take the arithmetic mean of the valid test specimens as the test result. Note: Determination of valid test specimens: Take the arithmetic mean of each group of test results, discard the test data with a deviation exceeding ±15% of the mean value, and use the remaining data to re-take the arithmetic mean until the deviation of each data from the arithmetic mean meets the requirements. Test specimens whose test data meet the requirements are valid test specimens. 9 Test report
The test report should include the following:
A complete description of the anti-corrosion coating being tested, including the type, source, manufacturer, production date, production batch number, etc. of the anti-corrosion coating. 9.1
9.2 A complete description of the test specimen, including the test plate material, thickness, surface cleaning and pretreatment method before bonding. 9.3 Coating and bonding conditions when preparing the test specimen. 9.4 Average thickness of the anti-corrosion layer. Describe the steps and locations for measuring thickness. 9.5 Lap length of the specimen,
9.6 Conditioning procedure for the specimen before testing. Number of specimens to be tested (if any are discarded, this should be stated). 9.7
3 Maximum, minimum and average values ​​of shear strength. 9.8
Failure characteristics, including the estimated average percentage of the overlap area occupied by the cohesive failure of the anticorrosive coating and the adhesion failure with the metal. Appendix A
(Standard Appendix)
Parameters and information required for the test
Surface preparation procedures for the metal test panel before the anticorrosive coating is applied, such as surface cleaning and drying. A1
A2 Instructions for mixing anticorrosive coatings.
A3 Conditions for applying anticorrosive coatings, including coating rate or coating film thickness, number of coating layers, single-sided or double-sided coating, and the drying conditions required by 874
when multiple layers are applied.
SY/T 0041—1997
A4 Overlap conditions before pressurization, including room temperature, relative humidity, duration, and overlap operation mode adopted (open or closed). A5 Curing or hardening conditions, including the pressure applied, the time of pressurization, the method of pressurization, the heating rate (heating rate and constant temperature), and the temperature during pressurization (it should be stated whether the temperature at this time is the temperature of the bonding layer or the ambient temperature). A6 The conditioning procedure before the test should include the length of time, temperature and relative humidity. It can also be specified that a standard procedure is used. 875
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