This test method is applicable to the inspection of the bending performance of copper, aluminum and alloy rectangular cross-section conductors with a nominal size of 0.8 mm and above. This test method is to bend the test piece into a certain angle along the specified bending radius and observe the cracking of the tensile surface of the test piece after bending. GB 4909.6-1985 Bare wire test method Bending test Unidirectional bending GB4909.6-1985 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Test methods for bare wlres
Bend test
Single bend test
This standard adopts BS1639 (1964) ASTME290 (1981) with reference. 1 Scope of application
UDC 621.315.14
GB4909.6—85
1.1 This test method is applicable to the inspection of the bending performance of copper, aluminum and their alloy rectangular cross-section conductors with a nominal size of 0.8mm and above. 1.2 This test method is to bend the test piece into a certain angle along the specified bending radius and observe the cracking of the tension surface of the test piece after bending. 2 Test equipment
Figure 1a One-way bending test machine
Figure 2b One-way bending test device
D-bending cylinder diameter, D'a gauge and roller diameter; F-force 2.1 One-way bending test machine as shown in Figure 1. The bending function mechanism should ensure that the specimen can be evenly close to the bending cylinder surface during the bending process.
2.2 One-way bending test device as shown in Figure 2. The two supports should be able to rotate freely, and their diameters D are 30mm and 50mm. 2.3 The length of the bending cylinder and the length of the support roller or pressure roller should be greater than the width of the specimen, and have sufficient rigidity and finish. 3 Specimen preparation
Two specimens of appropriate length are cut from one end of the specimen that has passed the appearance inspection. The specimen should be straight and can be carefully straightened if necessary. 4 Test steps
4.1a-side unidirectional bending test
.1.1 Install the test piece on the test machine and fix one end of the test piece. 4.1.2 Select the bending cylinder according to the bending radius specified in the product standard and adjust the position of the pressure roller so that the test piece maintains good contact with the bending cylinder surface and does not twist when bending.
4.1.3 Start the test machine and bend the test piece steadily and slowly to the required angle. 4.2b Single-side bending test
National Bureau of Standards 1985-01-81 Issued
1985-12-01 Implementation
GB4909.6-85
4.2.1As shown in Figure 2, place the test piece on two horizontal supports of the test device. The distance between the supports is calculated according to the following formula
1=D+2.1a(mm)
Where: D. Diameter of the bending cylinder, mm
a—nominal size of side a of the test piece, mm.
4.2.2Select the bending pressure head according to the bending radius specified in the product standard, and adjust the relative position of the bending pressure head and the two supports so that the axis of the pressure head is perpendicular to the line connecting the centers of the two supports and is located at the midpoint. 4.2.3Start the testing machine, apply a force perpendicular to the plane of the test piece steadily and slowly, and bend the test piece to the required angle. 4.3 Check and record the tension surface state of the specimen after bending with normal vision. 5 Test results and calculations
The test results shall comply with the product standard Www.bzxZ.net
Additional notes:
This standard is proposed by the Ministry of Machinery Industry of the People's Republic of China. This standard is under the jurisdiction of the Shanghai Cable Research Institute of the Ministry of Machinery Industry. This standard was drafted by the Shanghai Cable Research Institute of the Ministry of Machinery Industry and others. The drafting persons of this standard are Wu Musheng and Shen Jianhua.
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