GB/T 4909.5-2009 English PDF (GBT4909.5-2009)

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GB/T 4909.5-2009: Test methods for bare wires -- Part 5: Bend test -- Reverse bend test
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 29.060.10 K 11
GB/T 4909.5-2009
Replacing GB/T 4909.5-1985
Test methods for bare wires -
Part 5. Bend test - Reverse bend test
Issued on. March 19, 2009 Implemented on. December 01, 2009 Issued by. General Administration of Quality Supervision, Inspection and Quarantine; Standardization Administration of PRC.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Test equipment ... 5
4 Preparation of test pieces ... 8
5 Test steps ... 9
6 Test results and assessment ... 10
Foreword
GB/T 4909 “Test methods for bare wires” is divided into twelve parts.
Part 1. General;
Part 2. Measurement of dimensions;
Part 3. Tensile test;
Part 4. Torsion test;
Part 5. Bend test - Reverse bend test;
Part 6. Bend test - Single bend test;
Part 7. Part 7. Mandrel winding test;
Part 8. Hardness test - Brinell hardness test;
Part 9. Test for continuity of coating - Sodium polysulfide solution method;
- Part 10. Test for continuity of coating -Ammonium persulfate solution method;
- Part 11. Test for adherence of coating;
- Part 12. Solderability test of coating - Solder globule method. This part is part 5 of GB/T 4909. This part replaces GB/T 4909.5-1985 “Test methods for bare wires -Part 5.
Bend test - Reverse bend test”.
As compared with GB/T 4909.5-1985, the main changes in this part are as
follows.
- According to the requirements of GB/T 1.1-2000 “Directives for standardization - Part 1. Rules for the structure and drafting of standards”, MODIFY the compilation format, MODIFY some texts;
-EXPAND the scope of application of the standard (clause 1 of the 1985 version; clause 1 of this version);
ADD the clause “Normative references” (not available in the 1985 version; clause 2 in this version);
ADD the requirements for the size and position of curved cylinders and
Test methods for bare wires -
Part 5. Bend test - Reverse bend test
1 Scope
This part of GB/T 4909 specifies the test equipment, test piece preparation, measurement procedure, test results and evaluation of the reverse bend test in the bend test of bare wires.
This part is applicable to the determination of reverse bend performance of the round-section conductors such as copper, aluminum and its alloys, bimetallic wires and so on which have a nominal diameter d of 0.3 mm ~ 10.0 mm as well as the specially-shaped section conductors with characteristic size α ≤ 20.0 mm (such as contact wires).
This part uses a bending test in which one end of the test piece is fixed and the free end is 90° bent in the forward and reverse directions along a cylindrical surface of a predetermined radius, it is bent to a specified number of times or until the test piece is broken.
This part shall be used in conjunction with GB/T 4909.1-2009.
2 Normative references
The provisions in following documents become the provisions of this part through reference in this part of GB/T 4909. For the dated references, the subsequent amendments (excluding corrections) or revisions do not apply to this part; however, parties who reach an agreement based on this part are encouraged to study if the latest versions of these documents are applicable. For undated references, the latest edition of the referenced document applies.
GB/T 4909.1-2009 Test methods for bare wires - Part 1. General
3 Test equipment
3.1 General requirements
3.1.1 Round-section conductor reverse bend tester
The schematic diagram of the working principle of the reverse bend tester for the round-section conductor is shown in Figure 1.
3.1.2 Specially-shaped conductor reverse bend tester
The schematic diagram of the working principle of the reverse bend tester for the specially-shaped section conductor is shown in Figure 2.
3.2 Curved cylinders and clamping block
The curved cylinder and the clamping block shall have sufficient hardness, its cylindrical surface in contact with the test piece shall be polished, the surface roughness Rα shall be 0.63 µm.
The radius of the curved cylinder shall not exceed the nominal dimensional tolerance given in Table 1.
The axis of the curved cylinder shall be perpendicular to the plane of curvature and parallel to each other, they are in the same plane, the deviation shall not exceed 0.1 mm.
The clamping surface of the clamping block shall protrude slightly from the curved cylinder but shall not exceed 0.1 mm, that is, the spacing between the specimen and the curved cylinder on the connection line of the curvature centers of the two curved cylinders shall not be greater than 0.1 mm.
The top surface of the clamping block shall be below the connection line of the curvature centers of the two curved cylinders. When the radius r of the curved cylinder is equal to or less than 2.5 mm, the distance y from the plane of the curved cylinder’s axis to the closest point in contact to the test piece shall be
1.5 mm; when the radius of the curved cylinder is greater than 2.5 mm, the distance y from the plane of the curved cylinder’s axis to the closest point in contact to the test piece shall be 3 mm.
3.3 Bending arms and levers
For curved cylinders of all sizes, the distance from the axis of rotation of the bending arm to the top of the curved cylinder shall be 1.0 mm.
The both ends of the lever hole shall be slightly larger, the hole diameter is in accordance with Table 1.