Application scope:
This standard stipulates the terms and definitions of breaking tensile test method for steel strands, test principles, sample preparation, test instruments, test procedures and test reports.
This standard applies to the determination of breaking tensile of various types of steel strands and wire ropes. If the relevant product standards have other provisions, they shall be implemented in accordance with their provisions.
Test principle:
At room temperature, a tensile force is applied to the sample, which is generally pulled until there is broken wire, broken strand, or broken rope, and the strand breaking tensile force or other mechanical properties are measured.
Test equipment selection:
Select ZCG-W steel strand tensile testing machine; steel strand tensile testing machine according to the national standard for verification, should be one or better than one; strand tension testing machine chuck distance should meet the following table.Strand nominal diameter d
Sample minimum effective length L
D≤6
300
6<d≤20
600
d>20
30d
Note: The length of the sample is the minimum length L of the sample, a length of clamping, and special circumstances should be stated in the report.
experiment procedure:
1. In general, the test should be conducted at room temperature of 10°C-35°C. For special requirements, the test temperature shall be 23°C ± 5°C.
2, the test should be a smooth stretch, when the tensile force is not greater than 80% of the minimum breaking force of the strand, the test force can be quickly applied, and then should be slowly increased, the stress rate is about 10 MPa / s
3, for the casting method, the cast sample is placed in the jaw seat, and the tensile test can be performed. For the strand tension tester, let the lower jaw hang, adjust the specimen so that it coincides with the axis of the jaw seat, adjust the zero point of the tester, and then perform the tensile test.
4. For the cuff method, the sample that has pressed the sleeve directly clamped in the jaws can be subjected to a tensile test.
5, for the direct clamping method, the two ends of the sample directly clamped in the jaw, you can implement the tensile test.
6. For the winding method, clamp one end of the specimen first, then wrap the specimen around the test wheel, tighten the specimen, and finally clamp the other end to perform the tensile test.
7, in the determination of broken strand breaking force, if the need to determine the elongation, it is recommended to use casting method, according to the agreement can also determine the initial broken wire tension or broken stock tension, fracture characteristics and other items.
8. If the specimen is broken within 1d (30 mm) from the chuck or cutting point, the test is invalid. When the measured breaking tensile force meets the relevant standards, the test is valid; otherwise, the test is invalid.
9. Judgment result: The tensile force of the sample when the strand is broken (single stranded broken wire) is used as the measured breaking tensile force.
10. For arbitration trials, if there are no provisions in the product standards, the test methods shall be determined by the parties to the dispute.
For specific details, please consult the technical department of Jinan Zhongchuang Industrial Test System Co., Ltd.
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