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General test method for copper clad aluminum wire copper layer
- Feb 01, 2018 -

The copper clad aluminum wire is a bimetallic wire with a carefully coated copper layer on the aluminum core.

Compared with pure copper wire, it has many advantages: first, the density of aluminum is much lower than copper, so that the density of copper clad aluminum wire is far lower than that of pure copper wire, this means that under the condition of same weight, the length of the copper clad aluminum wire is much longer than pure copper wire, this greatly saves copper resources.

Second, the same length of copper clad aluminum cable is lighter than the pure copper wire, so it is convenient to transport and install, reducing the laying cost.

In addition, copper clad aluminum wires are more malleable than pure copper wires, and unlike aluminum, which produces insulating oxides, it is easier to process.

Copper clad aluminum is much less valuable to larceny than pure copper because it is almost impossible to separate the copper clad layer from the aluminum conductor.

Therefore, additional anti-theft effect can be received.

Due to many advantages of copper clad aluminum wire, production began in developed countries in the 1970s and has been widely used.

Due to the shortage of copper resources, in order to reduce the cost, more and more enterprises in China began to produce this kind of copper clad aluminum wire which can replace copper wire.


Due to the widespread application of copper clad aluminum wire, electronics industry, formulate the relevant industry standard SJ/T 11223-11223, which established a copper clad aluminum wire product classification, requirements, test methods, inspection rules, packaging, mark, transportation, storage, etc.

The uniformity of copper layer along circumference and longitudinal distribution of copper clad aluminum wire has a great influence on electromagnetic wave transmission performance.

The volume ratio of the copper layer is an important economic indicator.

Accordingly, standard pair of copper layer thickness and copper volume ratio have corresponding regulation.

According to the analysis of the structure of the copper clad aluminum wire and copper layer along the circumferential direction should be evenly distributed outside the aluminum conductor, good concentricity and standards according to its structure characteristics, the copper clad aluminum wire copper layer thickness of the thin point or the determination of copper layer volume made the test method of "section polishing method".

From the sample end intercepting the appropriate length of copper clad aluminum wire samples, the conductor cross section after grinding, polishing, with enough accuracy of reading microscope of perpendicular shown below four position determination of copper layer thickness, the four positions should be included in the copper layer is the thinnest part.

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Determination of copper thickness.


The copper layer thickness is calculated by the mean value of four position measurements, and the copper layer volume ratio is calculated according to the formula.


S = [1 - (D - 2 t) 2 / D2] * 100%...

(1)


In the formula: s-copper layer volume ratio;


D - copper clad aluminum wire diameter (mm);


T - average thickness of copper layer (mm).