GB/T 21652-2017Copper and copper alloy wire (English PDF)

3.1 Product classification

3.2 Chemical composition

The chemical composition of each designation of the wire shall comply with the provisions of GB/T 5231.

3.3 External dimensions and their allowable deviation

3.4 Mechanical properties

3.4.1 The tensile strength at room temperature and the elongation after fracture of the wire shall meet the requirements in Table 4.

3.7 Torsion test

Wires can be subjected to the torsion test, where the requirements shall be negotiated between the supplier and the buyer.

3.8 Wrapping test

The silicon bronze and tin bronze wires used as springs shall be subjected to a wrapping test, where they shall be wound 10 times on a cylinder twice the diameter of the wire without cracking.

3.9 Residual stress

3.10 Fracture inspection

The fracture of the wire shall be dense, without shrinkage, while slight defects that do not affect the use are allowed. The size and quantity of the defects shall comply with the provisions of YS/T 336.

3.11 Grain size

Wires can be tested for grain size, where the requirements shall be negotiated between the supplier and the buyer.

3.12 Surface quality

The surface of the wire shall be smooth and clean, and there shall be no defects that affect its use.

3.13 Coil weight

4.1 Chemical composition

The chemical composition analysis method of the wire shall be carried out according to the provisions of GB/T 5121 (all parts), YS/T 482 or YS/T 483, and the arbitration shall be carried out according to the provisions of GB/T 5121 (all parts).

4.2 Dimensions and their allowable deviation

The measurement method of the outer dimension of the wire shall be carried out in accordance with the provisions of GB/T 26303.2.

4.3 Mechanical properties

4.4 Hydrogen embrittlement test

The hydrogen embrittlement test method of the wire shall be carried out according to the provisions of GB/T 23606 for closed bending test method.

4.5 Reverse bend test

The reverse bend test method of the wire shall be carried out according to the provisions of GB/T 238.

4.8 Residual stress

The residual stress test method of the wire shall be carried out according to the provisions of GB/T 10567.2.

4.9 Fracture

The fracture test method of the wire with diameter (or distance across sides) >= 5.0 mm shall be carried out according to the provisions of YS/T 336, and the fracture of the wire with diameter (or distance across sides) < 5.0 mm shall be sampled and inspected at the wire blank.

4.10 Grain size

The grain size test method of the wire shall be carried out according to the provisions of YS/T 347.

4.11 Surface quality

The surface quality of the wire shall be inspected visually.

5.1 Inspection and acceptance

5.1.1 The wire shall be inspected by the technical supervision department of the supplier to ensure that the product quality complies with the provisions of this Standard and the order form (or contract); the quality certificate shall be filled.

5.2 Batch

Wires shall be submitted in batches. Each batch shall consist of products of the same designation, state and specification, and the weight of each batch shall not exceed 1 500 kg.

5.3 Inspection items

5.3.1 Each batch of wires shall be inspected for chemical composition, external dimensions and deviation, tensile strength and elongation after fracture, fracture, surface quality and coil weight.

5.3.6 When required by the buyer, each batch of wires shall also be inspected for hardness, torsion test, and grain size.

5.4 Sampling

The sampling of the wires shall comply with the requirements in Table 7. The sampling method shall be carried out in accordance with the provisions of YS/T 668, and the preparation of samples for mechanical properties shall be carried out in accordance with the provisions of YS/T 815.

5.5 Determination of the test result

5.5.1 When the chemical composition is unqualified, judge the batch of wires as unqualified.

5.5.2 When the external dimension of the wire and its allowable deviation and surface quality are unqualified, judge the coil as unqualified. When the number of unqualified pieces in each batch exceeds the acceptance quality limit, judge the whole batch as unqualified; alternatively, the supplier shall inspect coil by coil, and deliver the qualified ones.