GB/T 15748: Evolution and historical versions
| Standard ID | Contents [version] | USD | STEP2 | [PDF] delivered in | Standard Title (Description) | Status | PDF |
| GB/T 15748-2025 | English | 199 |
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The method of galvanic corrosion test for metallic ship meterials
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GB/T 15748-2025
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| GB/T 15748-2013 | English | 169 |
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The method of galvanic corrosion test for metallic ship materials
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GB/T 15748-2013
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| GB/T 15748-1995 | English | 199 |
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The method of galvanic corrosion test for metallic ship materials
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GB/T 15748-1995
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Basic data | Standard ID | GB/T 15748-2025 (GB/T15748-2025) | | Description (Translated English) | The method of galvanic corrosion test for metallic ship meterials | | Sector / Industry | National Standard (Recommended) | | Classification of Chinese Standard | A29 | | Classification of International Standard | 47.020.05 | | Word Count Estimation | 10,173 | | Date of Issue | 2025-08-29 | | Date of Implementation | 2026-03-01 | | Older Standard (superseded by this standard) | GB/T 15748-2013 | | Issuing agency(ies) | State Administration for Market Regulation; Standardization Administration of China | GB/T 15748-2025: The method of galvanic corrosion test for metallic ship meterials---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/GBT15748-2025
ICS 47.020.05
CCSA29
National Standards of the People's Republic of China
Replaces GB/T 15748-2013
Test methods for galvanic corrosion of marine metallic materials
Published on 2025-08-29
Implemented on 2026-03-01
State Administration for Market Regulation
The State Administration for Standardization issued a statement.
Foreword
This document complies with the provisions of GB/T 1.1-2020 "Standardization Work Guidelines Part 1.Structure and Drafting Rules of Standardization Documents".
Drafting.
This document supersedes GB/T 15748-2013 "Test Method for Galvanic Corrosion of Marine Metallic Materials" and is consistent with GB/T 15748-2013.
Aside from structural adjustments and editorial changes, the main technical changes are as follows.
a) Some test equipment and technical requirements have been added (see Chapter 4);
b) Added real-world marine environmental conditions (see Chapter 6);
c) Added instructions for using the testing equipment under laboratory conditions (see 7.2);
d) The experimental procedures under actual sea conditions were added, and the reference electrode fixing position was increased (see 7.3);
e) The sample mounting method has been changed (see 7.3, 6.2 in the.2013 edition);
f) Increased testing requirements under actual marine environmental conditions (see 7.4);
g) The calculation of the average galvanic corrosion rate has been modified (see 8.2, 7.2 in the.2013 edition);
h) Corrosion morphology observation has been added (see 8.4).
Please note that some content in this document may involve patents. The issuing organization of this document assumes no responsibility for identifying patents.
This document was proposed and is under the jurisdiction of the National Technical Committee on Standardization of Marine Ships (SAC/TC12).
This document was drafted by. Luoyang Shipbuilding Materials Research Institute (China Shipbuilding Group Corporation No. 725 Research Institute).
The main drafters of this document are. Zhang Penghui, Guo Weimin, Peng Wenshan, Ding Kangkang, Liu Shaotong, Fan Lin, Cheng Wenhua, Sun Mingxian, and Lin Cunguo.
Xu Likun, Hou Jian, Liu Guangyi, Ma Li, Xing Shaohua, Zheng Guohua, Liu Zhaohui.
This document was first published in.1995, revised for the first time in.2013, and this is the second revision.
Test methods for galvanic corrosion of marine metallic materials
1.Scope
This document describes the galvanic corrosion test method for marine metallic materials.
This document applies to the use of two different metals in artificial seawater, natural seawater, or chlorinated water at a mass percentage concentration of 3.5% under laboratory conditions.
Galvanic corrosion tests in sodium solution and under electrical connection conditions in a real marine environment. Galvanic corrosion of metallic materials used in marine engineering and other industrial equipment.
For reference in corrosion testing.
2 Normative references
The contents of the following documents, through normative references within the text, constitute essential provisions of this document. Dated citations are not included.
For references to documents, only the version corresponding to that date applies to this document; for undated references, the latest version (including all amendments) applies.
This document.
GB/T 1031 Product Geometric Specification (GPS) - Surface Roughness Parameters and Their Values Using the Surface Structure Profile Method
GB/T 6384 Test methods for seawater corrosion of metallic materials used in marine engineering in natural environments
GB/T 10123 Corrosion Terminology for Metals and Alloys
GB/T 42672 Monitoring methods for environmental factors in seawater exposure tests for corrosion of metals and alloys.
3.Terms and Definitions
The terms and definitions defined in GB/T 10123 apply to this document.
4.Test Equipment
4.1 The main test equipment includes. a zero-resistance ammeter and a high-precision multimeter, or a galvanic corrosion measuring instrument, or an electrochemical workstation; a reference electrode;
Electronic balance; high-resolution camera and microscope; laboratory testing apparatus also includes a constant temperature water bath and glass container; real marine environment.
The testing equipment also includes a multi-parameter water quality analyzer.
4.2 Zero-resistance ammeter. minimum range not greater than 0.1μA, measurement accuracy can reach ±1%.
4.3 High-precision multimeter. minimum range not greater than 0.1mV, measurement accuracy can reach ±1%.
4.4 Galvanic corrosion measuring instrument or electrochemical workstation. Minimum range and measurement accuracy are the same as zero-resistance ammeters and high-precision multimeters, and it has self-...
It features continuous measurement function, with a minimum time interval of less than 1 hour for timed measurements.
4.5 Reference electrode. Potential fluctuation is less than 5mV, calibration is required before use, and the potential is stable during the test.
4.6 Electronic balance. Measurement accuracy not less than 0.1 mg.
4.7 Camera. Resolution 1920×1080 pixels and above.
4.8 Microscope. Magnification of 100x or higher.
4.9 Constant temperature water bath device. The temperature can be controlled at 35℃ with an accuracy of 0.5℃.
4.10 Multi-parameter water quality analyzer. Technical parameters and performance characteristics comply with the provisions of GB/T 42672.
4.11 Glass containers.
5.Test Samples
5.1 The sample size should preferably be 100mm × 30mm, with a thickness of 2mm to 4mm. Other sizes are acceptable if there are special requirements.
5.2 The specimens should preferably be prepared by mechanical processing, and the surface roughness should comply with the requirements of GB/T 1031, with a maximum permissible value of Ra of 3.2 μm.
The samples should be cleaned of oil and dried in accordance with GB/T 6384.
5.3 There should be at least 3 pairs of parallel test specimens, and at least 3 uncoupled control test specimens.
5.4 Mark one end of the sample, either by punching a marking hole or by marking with steel lettering.
6.Test conditions
6.1 Under laboratory conditions, the test solution is natural seawater, artificial seawater (see Appendix A), or a solution with a pH of 7-8 and a concentration of 3.5% (by mass).
(Fractional) Sodium chloride solution. Artificial seawater and sodium chloride solution are prepared from analytical grade reagents and distilled water (or deionized water). Natural seawater.
The test solution should be prepared after sedimentation or filtration, and the salinity and pH of the natural seawater should be measured and recorded before the test begins. Real-world marine environmental conditions.
Before the test begins, the salinity and pH of the seawater at the test site shall be measured in accordance with the provisions of GB/T 42672.
6.2 Under laboratory conditions, the solution temperature during the experiment should be 35℃±2℃. Under actual marine environmental conditions, the temperature during the experiment should be the natural seawater temperature.
The seawater temperature shall be measured in accordance with the provisions of GB/T 42672.
6.3 The test period should preferably be 15 days, but can be determined through negotiation as needed.
6.4 Under laboratory conditions, the composition of the test solution and the test temperature can also be determined through negotiation as needed.
7.Experimental Procedure
7.1 Weigh the sample before and after the test, accurate to 0.1 mg.
7.2 The ratio of the cathode to anode area of the test couple should be as consistent as possible with the operating condition. Alternatively, the area of the coating area on the cathode and anode can be changed.
The cathode/anode area ratio is adjusted for testing. The connection between the wire and the sample is sealed to ensure insulation. Epoxy sealant or silicone sealant can be used.
Rubber coating. Ensure there are no gaps between the coating and the sample substrate during coating.
7.3 Different metal samples were paired up, with the two samples in each pair facing each other and placed parallel to each other, to facilitate comparison of different materials.
To ensure the galvanic corrosion resistance of the specimens, the shape and size of the specimens, the spacing between the couples, and the test conditions should be kept consistent. If the specimen areas are different, the two...
The horizontal center lines of the specimens are at the same height. Tests are conducted according to different test conditions, specifically in the following two aspects.
a) Under laboratory conditions, place the prepared pair into a glass container, add the test solution, and place it in a heated constant-temperature water bath.
The ratio of liquid volume to the maximum sample area of the paired sample should not be less than 20 mL/cm², the distance between the two samples should preferably be 30 mm, and each pair of samples should be flat.
The distance between the samples remains constant. One pair of pairs is placed in each glass container. Electrically connect the pairs as shown in Figure 1, and configure the testing equipment.
Zero-resistance ammeters and high-precision multimeters can be used, or galvanic corrosion measuring instruments with automatic continuous testing functions, or electrochemical instruments.
The reference electrode is a saturated calomel electrode with a salt bridge. The electrode position is on the same horizontal plane as the center point of the pair, and as close as possible...
The sample is placed close to the coupled anode. The control sample is subjected to corrosion tests simultaneously under the same conditions in the uncoupled state.
b) Under actual marine conditions, the paired samples were fixed in the fully submerged seawater area of the test site to ensure that the test samples were always at the lowest tide level.
Below this position, the distance between two samples should be 30 mm, and the distance between each set of parallel samples should remain constant. Connect the electrical coupler as shown in Figure 2.
Yes. The reference electrode is an Ag/AgCl electrode. The reference electrode is located on the same horizontal plane as the center point of the pair and is as close as possible to it.
Coupled anode samples. A custom-made test frame can be used to fix the sample and electrode positions. The frame should ensure unobstructed seawater flow and should be lowered.
The influence of low-grade seawater sediment or foreign matter on the electrodes. A polymer material is recommended for the frame. A galvanic corrosion measurement instrument should be selected.
An instrument or electrochemical workstation can automatically and continuously monitor the process. Comparative samples were simultaneously subjected to corrosion testing under the same conditions in an uncoupled state.
test.
a) b)
Index number explanation.
1---Zero-resistance ammeter;
2---Switch;
3---High-precision multimeter;
4---Reference electrode;
5---Sample;
6---Glass beaker;
7---A galvanic corrosion measuring instrument or electrochemical workstation with automatic continuous testing function.
Note 1.Figure 1a) was measured using a zero-resistance ammeter and a high-precision multimeter.
Note 2.Figure 1b) uses a galvanic corrosion measuring instrument or electrochemical workstation with automatic continuous testing function for measurement.
Figure 1.Configuration and electrical connection of the thermocouple pair under laboratory conditions.
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