The development of CCS in China

Since 2001, it has been produced for copper casting, rolling and electroplating processes

Baotou steel has short length, uneven copper layer, wire drawing is easy to break, and pollution rings

and other defects, suitable for large length, high strength, large environment, corrosion-resistant composite

In 2001, it was independently developed by a company in Shanghai

The cladding copper production line is obtained.

Wrap the integrated circuit and weld it into a tube at the wrapped interface by fire welding.

Special rolling, brushing and varnishing processes combine copper and copper into one

Since 2003, all sales have been formed.

Global sales, product quality level in line with the world. Its characteristic is the product

The coating layer is thin and evenly long, especially suitable for communication, electronics,

Wire for power transmission; the price is insufficient, and it is difficult to combine bimetals

technical difficulties.

 

 

At the same time, various other processes such as horizontal continuous casting also came into being. Horizontal continuous casting is the continuous casting of copper liquid directly on the steel wire, in the mold cool to form a copper cladding. There is an alloy layer on the copper-steel contact surface, the alloy layers have an effect on conductivity. It is suitable for the production of large cross-section, large length complex The thickness of the composite layer can be selected arbitrarily and the bonding performance is good.The disadvantage is that the uniformity of the thickness of the composite layer is relatively poor, and there is an eccentric core, which is not suitable for small-sized composite wire with high electrical performance requirements.

This stage is three kinds of electroplating method, cladding method and horizontal continuous casting method The technology occupies the market. Before the development of domestic cladding copper-clad steel, the domestic high-end market is imported copper-clad steel wire from

Copperweld Bimetallics, LLC. There are agents. However, in 2003, after the domestic cladding method was put into production, the price ratio of Copperweld Bimetallics, LLC was low and had the same quality and performance. At that time, Copperweld Bimetallics, LLC’s copper price of clad steel wire drops again and again, the conductivity is 40%, the diameter is Φ0. 25 mm

The price of copper-clad steel wire is 80,000/t, and the price of domestic cladding method is

60,000/t; when the price of Copperweld Bimetallics, LLC in the United States drops to 60,000/t, domestic package recovered down to 56,000/t. By 2005, agents were unable to sell and withdrawn from the Chinese market. In 2007, the copper clad of Copperweld Bimetallics, LLC in the United States Steel production declined, and a domestic company bought the former world’s largest copper-clad steel company, American Kopwei Bimetals Co., Ltd. But the company’s sales volume of the products in China is not large, and the domestic market is basically dominated by  three major domestic products. Process occupation, the main reason for analysis is cost.

The following are some discussion of the main production processes, product quality, production cost and the development of new products.

2 Main copper-clad steel processes at home and abroad

Domestic applications are more electroplating method, coating method and horizontal connection.

Cast copper clad steel process. The hot-rolled double copper strip is used more abroad.

method, cladding method and hot dip plating method. First introduce the key to various processes

The process characteristics are convenient for the comparison of product quality and performance later.

2.1 Electroplating process

The electroplating process is used for copper-clad steel wires with a conductivity below 30%.

the most. The process flow of producing copper-clad steel wire by electroplating is shown in Figure 1.

Figure 1 Process flow chart of copper-clad steel wire production by electroplating

It can be seen from Figure 1 that the process is mainly composed of three parts. First, the surface of the steel wire is treated, the oil is removed and the oxide layer is removed, and then copper or nickel is pre-plated.

Thicken the copper layer, clean it later, and add antioxidants or surface passivators.

The basic principle of electroplating copper-clad steel [4]: ​​The steel wire that has been pre-treated and pre-plated with nickel is immersed in the electroplating solution, and the steel wire (cathode) and the copper plate are immersed in the electroplating solution.

A certain voltage is applied to (anode). On the anode, the copper plate continuously loses electrons and forms free copper ions under the action of electrolysis

Dissociated in the electroplating solution: Cu-2e →Cu2+, on the cathode, under the action of electrolysis of the steel wire, the bivalent copper ions regain electrons and sink

Accumulated on the surface of the steel wire to form a copper-clad steel wire: Cu2+ + 2e →Cu,
Cu2++ →  e Cu+,Cu++ → e Cu,2H++2e →H2。

To plate copper ions on the surface of the steel wire, it is necessary to prevent the direct redox reaction between iron and copper ions. The direct redox reaction between steel and copper ions is the most basic problem to be solved by iron-based copper electroplating. This process can be expressed as: Fe +Cu2 → + Fe2+ + Cu;Fe2

The steel wire itself provides electrons and is converted into ferrous ions, which means the dissolution of the steel wire, which forms the so-called rotten wire. The replaced copper layer formed by this process does not involve electrodeposition, and the bond is very weak. To prevent possible dissolution of the steel wire, pre-plating must be used.

Mature pre-plating processes are cyanide plating, copper nickel plating and high phosphorus ratio pyrophosphate copper plating. Cyanide copper plating solution has good dispersibility and good coating

Dense, strong adhesion and other characteristics. However, it is difficult for domestic equipment to solve the environmental protection problem of cyanide, and other formulas are generally used. In subsequent wire drawing add for the electroplating of workers, it is better to use nickel plating as a pre-plating base. The main plating (thickening) copper can be acid sulfate copper plating or fluoboric acid.

Therefore, the electroplating process must improve the adhesion, compactness, continuity and stability of the copper layer in order to obtain high-quality Copper-clad steel wire, this is the difficulty of electroplating, and it is more difficult to increase the thickness of the coating layer in electroplating. The general wire diameter is only 2.5 mm or less conductivity is below 20%.

cladding process

The process of producing copper-clad billet wire by cladding welding method is mainly composed of raw material pretreatment, cladding welding and copper-steel bonding. The pretreatment of raw materials is mainly to thoroughly clean the copper strip and steel wire before cladding, to remove the oil stains and oxides on the surface, so as to ensure the good adhesion of the copper clad steel wire. Overlap soldering is where the copper tape enters the soldered

After setting, it is gradually formed, and the steel wire is covered in the process of forming the round tube, and then the two parts of the longitudinal seam of the copper tube that is constantly moving forward are welded by argon tungsten arc welding.

The edges are welded together to form a uniformly clad copper-clad steel wire billet. Copper-steel bonding through specially developed special processes and equipment, using special rolling

Pulling process, the copper and steel are bonded together to form a good bond between atoms. Production process of copper-clad steel double gold wire by clad welding method

see Figure 2

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