GB/T 15748-2025 The method of galvanic corrosion test for metallic ship meterials English, Anglais, Englisch, Inglés, えいご
This is a draft translation for reference among interesting stakeholders. The finalized translation (passing through draft translation, self-check, revision and verification) will be delivered upon being ordered.
ICS 13.340.01
CCS H 57
National Standard of the People's Republic of China
GB/T 15748-2025
Replaces GB/T 15748-2013
The method of galvanic corrosion test for metallic ship meterials
Issue date: 2025-08-29 Implementation date: 2026-03-01
Issued by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China
the Standardization Administration of the People's Republic of China
Contents
Foreword
1 Scope
2 Normative References
3 Terms and Definitions
4 Test Equipment
5 Test Samples
6 Test Conditions
7 Test Procedure
References
The method of galvanic corrosion test for metallic ship meterials
1 Scope
This document specifies the electrochemical corrosion test method for marine metallic materials.
This document applies to the electrochemical corrosion testing of two different metals in an electrically connected state under laboratory conditions in artificial seawater, natural seawater, or a sodium chloride solution with a mass percentage concentration of 3.5%, as well as in real marine environments. It also serves as a reference for the electrochemical corrosion testing of metallic materials used in marine engineering and other industrial equipment.
2 Normative References
The following documents contain provisions that, through normative references in this document, constitute essential requirements. For dated references, only the editions cited apply. For undated references, the latest edition (including any amendments) applies.
GB/T 1031: Product Geometrical Specifications (GPS) – Surface Structure – Profile Method – Surface Roughness Parameters and Their Values
GB/T 6384: Test Method for Corrosion of Metallic Materials in Natural Seawater for Marine and Offshore Engineering
GB/T 10123: Corrosion of Metals and Alloys – Terminology
GB/T 42672: Test Method for Monitoring Environmental Factors in Surface Seawater Exposure
3 Terms and Definitions
The terms and definitions defined in GB/T 10123 apply to this document.
4 Test Equipment
4.1 Main Equipment: Zero-resistance ammeter, high-precision multimeter, or electrochemical corrosion measuring instrument, or electrochemical workstation; reference electrode; electronic balance; high-resolution camera and microscope; for laboratory conditions, additional equipment includes a constant-temperature water bath and glass container; for real marine environment conditions, additional equipment includes a multi-parameter water quality analyzer.
4.2 Zero-resistance ammeter: Minimum range ≤ 0.1 μA, measurement accuracy ±1%.
4.3 High-precision multimeter: Minimum range ≤ 0.1 mV, measurement accuracy ±1%.
4.4 Electrochemical corrosion measuring instrument or electrochemical workstation: Minimum range and measurement accuracy same as the zero-resistance ammeter and high-precision multimeter, with automatic continuous measurement function and minimum measurement interval < 1 h.
4.5 Reference electrode: Potential fluctuation < 5 mV, calibration required before use, stable during the test.
4.6 Electronic balance: Measurement accuracy ≥ 0.1 mg.
4.7 Camera: Resolution ≥ 1920 × 1080 pixels.
4.8 Microscope: Magnification ≥ 100×.
4.9 Constant-temperature water bath: Temperature control at 35 ± 0.5 ℃.
4.10 Multi-parameter water quality analyzer: Technical parameters and performance characteristics comply with GB/T 42672.
4.11 Glass container.
5 Test Samples
5.1 Sample dimensions: 100 mm × 30 mm × (2–4) mm. Other dimensions may be used if required.
5.2 Sample preparation: Mechanical machining method, surface roughness per GB/T 1031 (Ra ≤ 3.2 μm); degreased and dried per GB/T 6384.
5.3 Parallel samples: ≥3 pairs of coupled samples, ≥3 uncoupled control samples.
5.4 Marking: Mark sample ends with punched holes or steel lettering.
6 Test Conditions
6.1 Laboratory conditions: Test solution – natural seawater, artificial seawater (see Appendix A), or 3.5% (mass fraction) NaCl solution (pH 7–8). Artificial seawater and NaCl solution prepared from analytical-grade reagents and distilled/deionized water. Natural seawater must be settled/filtered, with salinity and pH measured before use. For real marine environment, measure salinity and pH per GB/T 42672 before testing.
6.2 Temperature: Laboratory – 35 ± 2 ℃; real marine environment – natural seawater temperature (measured per GB/T 42672).
6.3 Test duration: 15 d (or as agreed).
6.4 Customization: Solution composition and temperature may be adjusted as needed.
7 Test Procedure
7.1 Weighing: Weigh samples before and after testing (accuracy: 0.1 mg).
7.2 Cathode/anode area ratio: Match the ratio to the actual use condition; adjust by coating/sealing areas. Seal electrical connections with epoxy or silicone rubber (no gaps).
7.3 Coupling:
Laboratory: Place coupled samples in a glass container with test solution (≥20 mL/cm² per sample). Maintain sample spacing at 30 mm per group. Use a zero-resistance ammeter, multimeter, or electrochemical workstation. Reference electrode: saturated calomel electrode with salt bridge (positioned at sample center near anode). Uncoupled control samples tested simultaneously.
Real marine environment: Fix samples in the fully submerged zone (below lowest tide level). Maintain spacing at 30 mm per group. Use Ag/AgCl reference electrode (positioned at sample center near anode). Use a custom frame to ensure water flow and minimize sediment interference. Measure with an electrochemical corrosion measuring instrument. Uncoupled control samples tested simultaneously.
7.4 Under laboratory conditions, when using a zero-resistance ammeter and a high-precision multimeter, the galvanic potential and galvanic current of the coupled specimens shall be measured after 1 h, 4 h, 8 h, and 24 h of testing, while the corrosion potential of the control specimens is measured simultaneously. After 24 h, the measurement frequency shall be reduced to once in the morning and once in the afternoon at fixed times each day. When using a galvanic corrosion measuring instrument or electrochemical workstation with automatic continuous measurement functions, the measurement frequency is recommended to be once per hour. During the test, attention shall be paid to adding distilled or deionized water to the test solution to maintain the solution level at the same height as the original level. Under real marine environmental conditions, continuous measurements shall be performed by a galvanic corrosion measuring instrument or electrochemical workstation, with a recommended measurement frequency of once per hour, and a multi-parameter water quality analyzer shall be used to simultaneously measure the test temperature.
Standard
GB/T 15748-2025 The method of galvanic corrosion test for metallic ship meterials (English Version)
Standard No.
GB/T 15748-2025
Status
to be valid
Language
English
File Format
PDF
Word Count
6000 words
Price(USD)
180.0
Implemented on
2026-3-1
Delivery
via email in 1~3 business day
Detail of GB/T 15748-2025
Standard No.
GB/T 15748-2025
English Name
The method of galvanic corrosion test for metallic ship meterials
GB/T 15748-2025 The method of galvanic corrosion test for metallic ship meterials English, Anglais, Englisch, Inglés, えいご
This is a draft translation for reference among interesting stakeholders. The finalized translation (passing through draft translation, self-check, revision and verification) will be delivered upon being ordered.
ICS 13.340.01
CCS H 57
National Standard of the People's Republic of China
GB/T 15748-2025
Replaces GB/T 15748-2013
The method of galvanic corrosion test for metallic ship meterials
Issue date: 2025-08-29 Implementation date: 2026-03-01
Issued by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China
the Standardization Administration of the People's Republic of China
Contents
Foreword
1 Scope
2 Normative References
3 Terms and Definitions
4 Test Equipment
5 Test Samples
6 Test Conditions
7 Test Procedure
References
The method of galvanic corrosion test for metallic ship meterials
1 Scope
This document specifies the electrochemical corrosion test method for marine metallic materials.
This document applies to the electrochemical corrosion testing of two different metals in an electrically connected state under laboratory conditions in artificial seawater, natural seawater, or a sodium chloride solution with a mass percentage concentration of 3.5%, as well as in real marine environments. It also serves as a reference for the electrochemical corrosion testing of metallic materials used in marine engineering and other industrial equipment.
2 Normative References
The following documents contain provisions that, through normative references in this document, constitute essential requirements. For dated references, only the editions cited apply. For undated references, the latest edition (including any amendments) applies.
GB/T 1031: Product Geometrical Specifications (GPS) – Surface Structure – Profile Method – Surface Roughness Parameters and Their Values
GB/T 6384: Test Method for Corrosion of Metallic Materials in Natural Seawater for Marine and Offshore Engineering
GB/T 10123: Corrosion of Metals and Alloys – Terminology
GB/T 42672: Test Method for Monitoring Environmental Factors in Surface Seawater Exposure
3 Terms and Definitions
The terms and definitions defined in GB/T 10123 apply to this document.
4 Test Equipment
4.1 Main Equipment: Zero-resistance ammeter, high-precision multimeter, or electrochemical corrosion measuring instrument, or electrochemical workstation; reference electrode; electronic balance; high-resolution camera and microscope; for laboratory conditions, additional equipment includes a constant-temperature water bath and glass container; for real marine environment conditions, additional equipment includes a multi-parameter water quality analyzer.
4.2 Zero-resistance ammeter: Minimum range ≤ 0.1 μA, measurement accuracy ±1%.
4.3 High-precision multimeter: Minimum range ≤ 0.1 mV, measurement accuracy ±1%.
4.4 Electrochemical corrosion measuring instrument or electrochemical workstation: Minimum range and measurement accuracy same as the zero-resistance ammeter and high-precision multimeter, with automatic continuous measurement function and minimum measurement interval < 1 h.
4.5 Reference electrode: Potential fluctuation < 5 mV, calibration required before use, stable during the test.
4.6 Electronic balance: Measurement accuracy ≥ 0.1 mg.
4.7 Camera: Resolution ≥ 1920 × 1080 pixels.
4.8 Microscope: Magnification ≥ 100×.
4.9 Constant-temperature water bath: Temperature control at 35 ± 0.5 ℃.
4.10 Multi-parameter water quality analyzer: Technical parameters and performance characteristics comply with GB/T 42672.
4.11 Glass container.
5 Test Samples
5.1 Sample dimensions: 100 mm × 30 mm × (2–4) mm. Other dimensions may be used if required.
5.2 Sample preparation: Mechanical machining method, surface roughness per GB/T 1031 (Ra ≤ 3.2 μm); degreased and dried per GB/T 6384.
5.3 Parallel samples: ≥3 pairs of coupled samples, ≥3 uncoupled control samples.
5.4 Marking: Mark sample ends with punched holes or steel lettering.
6 Test Conditions
6.1 Laboratory conditions: Test solution – natural seawater, artificial seawater (see Appendix A), or 3.5% (mass fraction) NaCl solution (pH 7–8). Artificial seawater and NaCl solution prepared from analytical-grade reagents and distilled/deionized water. Natural seawater must be settled/filtered, with salinity and pH measured before use. For real marine environment, measure salinity and pH per GB/T 42672 before testing.
6.2 Temperature: Laboratory – 35 ± 2 ℃; real marine environment – natural seawater temperature (measured per GB/T 42672).
6.3 Test duration: 15 d (or as agreed).
6.4 Customization: Solution composition and temperature may be adjusted as needed.
7 Test Procedure
7.1 Weighing: Weigh samples before and after testing (accuracy: 0.1 mg).
7.2 Cathode/anode area ratio: Match the ratio to the actual use condition; adjust by coating/sealing areas. Seal electrical connections with epoxy or silicone rubber (no gaps).
7.3 Coupling:
Laboratory: Place coupled samples in a glass container with test solution (≥20 mL/cm² per sample). Maintain sample spacing at 30 mm per group. Use a zero-resistance ammeter, multimeter, or electrochemical workstation. Reference electrode: saturated calomel electrode with salt bridge (positioned at sample center near anode). Uncoupled control samples tested simultaneously.
Real marine environment: Fix samples in the fully submerged zone (below lowest tide level). Maintain spacing at 30 mm per group. Use Ag/AgCl reference electrode (positioned at sample center near anode). Use a custom frame to ensure water flow and minimize sediment interference. Measure with an electrochemical corrosion measuring instrument. Uncoupled control samples tested simultaneously.
7.4 Under laboratory conditions, when using a zero-resistance ammeter and a high-precision multimeter, the galvanic potential and galvanic current of the coupled specimens shall be measured after 1 h, 4 h, 8 h, and 24 h of testing, while the corrosion potential of the control specimens is measured simultaneously. After 24 h, the measurement frequency shall be reduced to once in the morning and once in the afternoon at fixed times each day. When using a galvanic corrosion measuring instrument or electrochemical workstation with automatic continuous measurement functions, the measurement frequency is recommended to be once per hour. During the test, attention shall be paid to adding distilled or deionized water to the test solution to maintain the solution level at the same height as the original level. Under real marine environmental conditions, continuous measurements shall be performed by a galvanic corrosion measuring instrument or electrochemical workstation, with a recommended measurement frequency of once per hour, and a multi-parameter water quality analyzer shall be used to simultaneously measure the test temperature.
