GB/T 42661-2023 English PDF (GBT42661-2023)

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GB/T 42661-2023: Corrosion of metals and alloys - Test method for determining susceptibility to stress corrosion of steel reinforcement in simulated marine environment
GB/T 42661-2023
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.060
CCS H 25
Corrosion of Metals and Alloys - Test Method for
Determining Susceptibility to Stress Corrosion of Steel
Reinforcement in Simulated Marine Environment
ISSUED ON: AUGUST 6, 2023
IMPLEMENTED ON: MARCH 1, 2024
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative References ... 4
3 Terms and Definitions ... 5
4 Principle ... 5
5 Test Solutions ... 5
6 Specimens ... 6
7 Stress Corrosion Test by Constant-load Uniaxially Loaded Tension ... 7
8 Stress Corrosion Test by Slow Strain Rate ... 11
9 Test Report ... 12
Bibliography ... 13
Corrosion of Metals and Alloys - Test Method for
Determining Susceptibility to Stress Corrosion of Steel
Reinforcement in Simulated Marine Environment
1 Scope
This document specifies the principle, test solutions, specimens, test procedures and test report
of the test method for determining susceptibility to stress corrosion of steel reinforcement in
simulated marine environment.
This document is applicable to the test of susceptibility to stress corrosion of steel reinforcement
in simulated marine environment, such as: atmospheric areas, splash areas, tidal range areas
(water-level change areas) and seawater immersion areas, etc., under concrete pore fluid
conditions, using constant-load uniaxially loaded tension and slow strain rate methods.
2 Normative References
The contents of the following documents constitute indispensable clauses of this document
through the normative references in the text. In terms of references with a specified date, only
versions with a specified date are applicable to this document. In terms of references without a
specified date, the latest version (including all the modifications) is applicable to this document.
GB/T 1499.1 Steel for the Reinforcement of Concrete - Part 1: Hot Rolled Plain Bars
GB/T 1499.2 Steel for the Reinforcement of Concrete - Part 2: Hot Rolled Ribbed Bars
GB/T 10123 Corrosion of Metals and Alloys - Vocabulary
GB/T 15970.1 Corrosion of Metals and Alloys - Stress Corrosion Testing - Part 1: General
Guidance on Testing Procedures
GB/T 15970.4 Corrosion of Metals and Alloys - Stress Corrosion Testing - Part 4: Preparation
and Use of Uniaxially Loaded Tension Specimens
GB/T 15970.7 Corrosion of Metals and Alloys - Stress Corrosion Testing - Part 7: Slow Strain
Rate Testing
GB/T 16825.1-2022 Metallic Materials - Calibration and Verification of Static Uniaxial Testing
Machines - Part 1: Tension / compression Testing Machines - Calibration and Verification of
the Force-measuring System
6 Specimens
6.1 General Requirements
6.1.1 Steel reinforcements that comply with the stipulations of GB/T 1499.1 and GB/T 1499.2
shall be adopted. Generally, the cross-section of the steel reinforcements is circular, the surface
of the steel reinforcements is smooth round or ribbed, and the specifications are 6 mm ~ 50 mm.
6.1.2 If the testing machine satisfies the requirements, it is recommended to use raw materials
of steel reinforcements for testing. The recommended specimen specifications are 16 mm, and
the length is 2,000 mm. The clamping ends of the steel reinforcements can be machined to
satisfy the requirements of the testing machine. The surface of the parallel lengths between the
clamping parts shall not be machined in any mode.
6.1.3 Through negotiation between two parties of the test, the surface of the steel reinforcements
can also be cut. During process, the effect of external stress concentration shall be avoided, and
the shape and size of the specimens shall comply with the requirements of GB/T 15970.4.
For example, after machining of the steel reinforcements with specifications of 16 mm, the
gauge length of the specimen size can be 50 mm, and the cross-sectional size is 10.0 mm. Small
cross-section specimens can also be used, with the gauge length greater than 10 mm and the
cross-sectional size less than 3.0 mm.
6.1.4 Before the test, the appearance of the specimen shall be inspected to ensure that there are
no visible cracks or other defects that may affect fracture.
6.1.5 The quantity of specimens is generally 3 ~ 5, or as specified in relevant product standards
or as negotiated between both parties of the test.
6.2 Specimen Preparation
For the treatment of the steel reinforcements, use 10% sulfuric acid to wash them for 10 min ~
15 min at room temperature of 10 C ~ 35 C, and use distilled water or deionized water to
rinse them, until the surface reveals the true metal color; use hot air from a hair dryer to blow-
dry them.
The raw material specimens of the steel reinforcements shall be protected by anti-corrosion
methods, for example, painting, for at least 50 mm long when they enter the container.
The specimens should be marked with a permanent identification mark or number. In order to
avoid affecting the test results, pay attention to the position of the mark on the specimens and
keep it as far away from the test area as possible.
During specimen preparation, overheating or overpressure shall be avoided, otherwise, it will
cause residual stress or metallurgical changes on the surface. Heat treatment, chemical polishing
or electropolishing can be used to overcome this effect under certain circumstances. Care shall
also be taken to reduce contamination of the surface by polishing residues.
Other requirements shall comply with the stipulations of GB/T 15970.1 and GB/T 15970.4.
7 Stress Corrosion Test by Constant-load Uniaxially Loaded
Tension
7.1 Selection of Corrosive Solution
In accordance with the purpose of the test, and the requirements of Chapter 5, select and prepare
the corresponding test solution. The test solution must be prepared immediately before use and
cannot be reused.
7.2 Test Procedures of Raw Material Specimens
7.2.1 Test devices
7.2.1.1 Test container
The material of the test container shall be resistant to corrosion by the test solution at 60  C.
Structural materials in contact with the test shall not be affected by corrosive agents, so as to
avoid contaminating the solution and changing the corrosiveness of the solution. When feasible,
the use of inert materials is recommended. The container shall remain closed during the test and
avoid the ingress of air.
The container shall be cylindrical, and the inner diameter shall be designed to ensure that the
specimen in contact with the solution contains at least 5 mL of solution per 100 mm2 of surface
area.
The container shall be of sufficient length, so that the test length immersed in the solution is not
less than 200 mm. The container shall be designed so that the specimen can pass through it,
meanwhile, the end of the specimen shall be thoroughly exposed outside the container, so as to
allow tensile force to be applied.
The schematic diagram of the test container is shown in Figure 1.
influence of the external stress.
7.2.6 Termination of test
When the specimen breaks, the test is completed. The specimen shall be removed in time, so as
to protect the fracture. If necessary, observe the fracture.
After the test has been proceeded to the specified time, even if the specimen is not broken, the
test can be terminated. At this moment, the specimen may contain cracks, but they have not yet
expanded to the extent of complete fra...