GB/T 29197-2012Copper-clad aluminum wire (English PDF)

3.1 Classification

Copper-clad aluminum wires are divided into the following six categories according to the copper layer volume ratio (10%, 15%, 20%) and the soft or hard state (soft state A, hard state H):

10A – soft copper-clad aluminum wire with a copper layer volume ratio of 10%;

10H – hard copper-clad aluminum wire with a copper layer volume ratio of 10%;

15A – soft copper-clad aluminum wire with a copper layer volume ratio of 15%;

15H – hard copper-clad aluminum wire with a copper layer volume ratio of 15%;

20A – soft copper-clad aluminum wire with a copper layer volume ratio of 20%;

20H – hard copper-clad aluminum wire with a copper layer volume ratio of 20%.

3.2 Model and marker

3.2.1 Model

The model of copper-clad aluminum wire consists of type code (CCA), category code (10A, 10H, 15A, 15H, 20A, 20H) and nominal diameter (mm).

Represented as follows:

3.2.2 Product marker

The product marker consists of name, model and the number of this Standard.

Example: soft copper-clad aluminum wire with a nominal diameter of 2.50 mm and a copper layer volume ratio of 15% is represented as: copper-clad aluminum wire CCA-

15A-2.50 GB/T 29197-2012

4.1 Appearance

The surface of the copper-clad aluminum wire shall be smooth and round, and shall be free of dents, scratches, bamboo joints, bubbles, cracks, exposed aluminum, and any defects that affect use.

4.2 Diameter

The diameter of the copper-clad aluminum wire shall meet the requirements in Table 1.

4.3 Copper layer thickness

The copper layer thickness of the copper-clad aluminum wire shall meet the following requirements:

a) For 10A and 10H copper-clad aluminum wires, the thinnest thickness shall not be less than 1.75% of the nominal diameter;

b) For 15A and 15H copper-clad aluminum wires, the thinnest thickness shall not be less than 2.5% of the nominal diameter;

c) For 20A and 20H copper-clad aluminum wires, the thinnest thickness shall not be less than 3.5% of the nominal diameter.

4.4 Copper layer volume ratio

The copper layer volume ratio of the copper-clad aluminum wire shall meet the following requirements:

a) For 10A and 10H copper-clad aluminum wires, the copper layer volume ratio shall be no less than 8% and no more than 12%;

b) For 15A and 15H copper-clad aluminum wires, the copper layer volume ratio shall be no less than 13% and no more than 17%;

c) For 20A and 20H copper-clad aluminum wires, the copper layer volume ratio shall be no less than 18% and no more than 22%.

4.5 DC resistivity

The DC resistivity of the copper-clad aluminum wire at 20°C shall meet the requirements in Table 2.

mm, visually inspect the appearance quality; for copper-clad aluminum wires with a nominal diameter less than 1.50 mm, use a magnifying glass with a magnification of no more than 10 times to inspect the appearance quality. When necessary, use other appropriate methods agreed upon by the manufacturer and the user to check.

5.2 Diameter

The diameter of the copper-clad aluminum wire shall be measured according to the provisions of GB/T 4909.2.

5.3 Copper layer thickness

For copper-clad aluminum wires with a nominal diameter greater than or equal to 2.00 mm, use metallographic sandpaper to grind and polish the cross-section, to meet the mirror surface requirements; use a reading microscope greater than 20 times to measure the thinnest copper layer thickness.

For copper-clad aluminum wires with a nominal diameter of less than 2.00 mm, the thinnest copper layer thickness shall be measured in accordance with the provisions of

Appendix A.

5.4 Copper layer volume ratio

Measure the diameter of copper-clad aluminum wire according to the provisions of 5.2.

According to the provisions of 5.3, measure the copper layer thickness at the four mutually perpendicular positions shown in Figure 1, which shall include the thinnest part of the copper layer.

Use the average of the measurements at four locations to calculate the average thickness of the copper layer.

Figure 1 – Measurement of average copper layer thickness

Calculate the copper layer volume ratio according to Formula (1):

Where:

r – copper layer volume ratio;

d – diameter of the copper-clad aluminum wire, in millimeters (mm);

t – average copper layer thickness, in millimeters (mm).

5.5 DC resistivity

The DC resistivity of the copper-clad aluminum wire is calculated by measuring the

DC resistance.

DC resistance measurement shall be carried out according to the provisions of GB/T

3048.2-2007. When the test temperature is not 20 °C, it shall be corrected to the resistance value at 20 °C according to Formula (9) in GB/T 3048.2-2007, where the temperature coefficient of resistance at 20 °C is 0.004055/°C (10A, 10H), 0.004049/°C (15A, 15H), 0.004042/°C (20A, 20H).

The DC resistivity shall be calculated according to Formula (2):

Where:

rho – DC resistivity, in ohm square millimeters per meter (ohm·mm

2

/m);

R – DC resistance, in ohms (ohm);

S – cross-sectional area, in square millimeters (mm

2

);

l – length, in meters (m).

5.6 Tensile strength and elongation at break

The tensile strength and elongation at break of copper-clad aluminum wire shall be tested according to the provisions of Appendix B. When the elongation at break is less than the specified value and the break point appears within 25 mm from the chuck of the testing machine or the gauge length of the extensometer, the data is invalid and the test shall be repeated.

5.7 Torsion

The torsion test of the copper-clad aluminum wire shall be carried out in accordance with the provisions of IEC 61196-1-310.

5.8 Reverse bend

The reverse bend test of the copper-clad aluminum wire shall be carried out in accordance with the provisions of GB/T 4909.5, and the sample shall be repeatedly bent until the sample breaks. After the test, check whether there is delamination between the copper layer and the aluminum core.

5.9 Density

Measure the diameter and length of the copper-clad aluminum wire according to the provisions of GB/T 4909.2. When the nominal diameter is greater than or equal to 1.5 mm, the length of the sample shall not be less than 1 000 mm; when the nominal diameter is less than 1.5 mm, the length of the sample shall not be less than 4 000 mm.

Use a balance with an accuracy of not less than 1 mg to measure its mass, and then calculate the density according to Formula (3):

Where:

D – density, in grams per cubic centimeter (g/cm

3

);

W – mass, in grams (g);

d – diameter, in millimeters (mm);

l – length, in millimeters (mm).

5.10 Joints

Visually inspect the joints and their markers, and use a weighing instrument with an accuracy of not less than 0.1 kg to measure the weight between adjacent joints. The diameter of the joint shall be measured according to the provisions of 5.2, and the tensile strength and elongation at break shall be measured according to the provisions of 5.6.

When sampling, the joint shall be located in the middle of the sample as much as possible.

6.1 General

Finished copper-clad aluminum wires can only leave the factory after passing the inspection of the quality inspection department of the manufacturer. Each batch of products leaving the factory shall be accompanied by an exit-factory inspection certificate. Inspection is divided into exit-factory inspection and type inspection.

The samples for type inspection shall be randomly selected from the inspection batches that have passed the exit-factory inspection, and the sample size shall be 3 reels (shafts).

Samples shall be taken from each sample unit (reel or shaft).

6.3.3 Type inspection cycle

In any of the following cases, type inspection shall be carried out:

a) Inspection and identification of new products or old products which are transferred to the factory;

b) After formal production, when raw materials, formulations or process conditions are changed;

c) During normal production, once a year;

d) When the product is put back on production after a long time of suspension;

e) When the exit-factory inspection results are significantly different from the normal production inspection results;

f) When proposed by the national quality supervision and inspection agency.

6.3.4 Acceptance and failure of type inspection

When the items specified in Table 6 are all qualified, the type inspection is qualified.

When the type inspection is unqualified, the sampling shall be doubled for re-inspection.

If it is still unqualified, judge it as unqualified. Then, the product delivery shall be stopped, the reasons shall be analyzed at the same time, and corrective measures shall be taken to eliminate the unqualified reasons. The exit-factory inspection can only be resumed after the new type inspection is qualified.

7.1 Packaging

Copper-clad aluminum wires shall be supplied in reels (shafts), neatly coiled, and properly packaged to prevent contamination, oxidation, and damage.

Copper-clad aluminum wire packaging shall be accompanied by an exit-factory inspection certificate of the product. Packaging materials shall meet environmental protection requirements, and there shall be corresponding marking on the outer packaging.

7.2 Marking

Each reel (shaft) of copper-clad aluminum wire shall be attached with a label or a tag indicating the following:

a) name or trademark of the manufacturer;

b) model;

c) production date;

d) gross weight and net weight;

e) product batch number;

f) inspector’s mark;

g) number of this Standard;

h) joint information;

i) others.

7.3 Transportation

During transportation, copper-clad aluminum wires shall be protected from moisture and corrosion, to prevent damage caused during loading, unloading, lifting, stacking and transportation.

7.4 Storage

Copper-clad aluminum wires shall be properly stored in a warehouse that is dry and ventilated (humidity not greater than 65%), rainproof, waterproof, and does not contain acid-base substances or harmful gases.

A.1 Test principle

In this test, after grinding and polishing the sample of the copper-clad aluminum wire to make the cross-section meet the requirements of the mirror surface, use a metallographic microscope to measure the thinnest copper layer thickness of the copper-clad aluminum wire with a nominal diameter of less than 2.00 mm.

A.2 Test device

Use a metallographic microscope with a magnification of not less than 100 times and a scale on the eyepiece.

A.3 Sample preparation

A.3.1 Sample cutting

Cut 6 samples with a length of about 15 mm from the extracted copper-clad aluminum wire sample. When cutting, the cross-sectional deformation of the wire shall be minimized.

A.3.2 Sample mounting

Stick the sample parallel to the tape with a width of about 10 mm at intervals of 2 mm

~ 3 mm. Stick the tape together with the sample on an aluminum rod with a diameter of about 5 mm and a length of about 15 mm. Stand the aluminum rod and sample vertically in an aluminum tube or plastic aluminum tube with a diameter of about 15 mm and a height of about 15 mm. Fill the gap between the two with epoxy resin, and set it aside after curing; alternatively, use bakelite powder on the mosaic machine for later use.

A.3.3 Grinding, polishing and etching of samples

Grind the mounted sample perpendicular to metallographic sandpaper. Grind on the coarser sandpaper first; when the direction of the wear marks is consistent, change to the finer sandpaper. Every time the sandpaper is replaced, the dust from the previous grinding must be removed, and the grinding direction of the sample must be turned 90°.

The grades of the sandpaper used are from coarse to fine: No. 280, No. 400, No. 800,

No. 1 000 and No. 1 500.

Appendix B (Normative)

Tensile strength and elongation at break test

B.1 Test principle

In this test, the tensile strength and elongation at break of the copper-clad aluminum wire are determined by applying a tensile force to a section of the sample.

Unless otherwise specified, this test shall be carried out at an ambient temperature of

10 °C ~ 35 °C.

B.2 Test device

The indication error of the force measuring system of the testing machine shall not be greater than 1%.

An extensometer with a gauge length greater than 250 mm or other suitable elongation measuring device shall be used. The device shall have a scale with a resolution better than 0.25 mm.

B.3 Sample

The original gauge length (L0 ) of the sample is 250 mm, and the total length of the sample is about 300 mm.

The sample shall be straightened manually or by other suitable means.

B.4 Test procedure

B.4.1 Determination of the original cross-sectional area (S0 )

Measure the diameter of the copper-clad aluminum wire according to the provisions of

GB/T 4909.2, and calculate the original cross-sectional area according to Formula (B.1):

Where:

S 0 – original cross-sectional area, in square millimeters (mm

2

);

d – diameter, in millimeters (mm).