Electromagnetic casting has been tried as early as 1970s in China, but it has not been industrialized. In recent years, electromagnetic casting technology has been greatly developed, and 200mm oxygen-free Copper Ingot has been successfully cast with smooth surface. At the same time, the electromagnetic field can accelerate the degassing and slag removal, and the oxygen content of oxygen less than 0.001% oxygen free copper can be obtained.

The new technology of copper alloy casting is based on the solidification theory through directional solidification, rapid solidification, semi-solid forming, electromagnetic stirring, modification, automatic control of liquid level and so on, the structure of billet is refined, densified and purified, and continuous operation and near final forming are realized. In the long run, the casting technology of copper and copper alloy will be semi-continuous casting technology and full continuous casting technology, and the proportion of continuous casting technology will be increasing. Copper and copper alloy casting is generally divided into: Vertical semi-continuous casting, vertical full-continuous casting, horizontal continuous casting, upward continuous casting and other casting technology.

A vertical semi-continuous casting

Vertical semi-continuous casting has the characteristics of simple equipment and flexible production. It is suitable for casting round and flat ingots of various copper and copper alloys. Vertical semi-continuous casting machine drive mode is divided into hydraulic, screw and wire rope, because the hydraulic transmission is more stable, has been more used. The crystallizer can be vibrated with different amplitude and frequency according to the need. At present, semi-continuous casting is widely used to produce copper and copper alloy ingots.

B Vertical full continuous casting

Vertical full continuous casting has the characteristics of large output and high rate of finished products (about 98%) . It is suitable for large-scale continuous casting with a single type and specification, is becoming a modern large copper strip production line on the melting and casting process one of the main options. The vertical continuous casting mould adopts non-contact laser liquid level automatic control, and the casting machine generally adopts hydraulic clamping, mechanical transmission, on-line oil-cooled dry chip sawing and picking up, automatic marking and slanting ingot, the structure of equipment is complex and the degree of automation is high.

C level continuous casting

Horizontal continuous casting can produce strip billet and tube-bar-wire billet. Copper and copper alloy strips with thickness of l 4 ~ 20 mm can be produced by continuous horizontal casting of Strip billets. The strips in this thickness range can be cold rolled directly without hot rolling, therefore, it is often used in the production of hot-rolled difficult alloy varieties (such as tin phosphorus bronze, lead brass, etc.) , can also produce brass, white copper and low-alloy copper alloy strip billet. According to the casting strip width, L ~ 4 strip can be cast simultaneously by horizontal continuous casting. The commonly used horizontal continuous casting machine can simultaneously cast 2 strips, each strip width less than 450 mm, or CAST 1 strip, strip width 650 ~ 900 mm. The horizontal continuous casting strip is usually cast by pull-stop-reverse casting process with periodic crystallization lines on the surface, which should be eliminated by milling. There are some examples in our country that high surface copper strip can be produced by casting strip billet without milling surface. According to different alloy and specification, 1 ~ 20 billets can be cast at the same time by horizontal continuous casting. The diameter of Rod Blank or wire blank is 6 ~ 400mm, the outside diameter of tube blank is 25 ~ 300mm. The Wall thickness is 5 ~ 50 mm, the side length of square ingot is 20 ~ 300 mm. The advantages of horizontal continuous casting method are short working procedure, low manufacturing cost and high production efficiency. It is also a necessary mode of production for some alloy materials with poor hot workability. Recently, it is the main way of making billets of common copper products such as tin phosphorus bronze strip, zinc white copper strip, phosphorus deoxy copper air conditioning pipe, etc. . It is also the main mode of production of lead brass bar, Tin Phosphorus Bronze Bar, tin zinc lead copper bar, silicon bronze Bar, etc. .

The disadvantages of the horizontal continuous casting method are as follows: The suitable alloy variety is relatively simple, the material consumption in the mold is large, and the crystal structure of the billet cross section is difficult to control. The lower part of the billet is continuously cooled because of the action of gravity close to the inner wall of the mould, and the grains are fine, while the upper part is slowed down because of the formation of the air gap and the solidification lag of the billet due to the higher melt temperature, however, the crystal structure is coarse, which is especially obvious for large size billet. In view of the above disadvantages, people are developing the casting method of vertical bend with billet at present. DHP and Cusn6 Tin Bronze Strips (16 ~ 18) mm 680 mm were produced by vertical bending continuous casting machine in Germany.

Continuous casting with D top drawing

Continuous casting is a rapidly developed casting technology in the past 20 or 30 years. It is widely used in the production of polished copper wire Rod. It uses vacuum suction casting principle and stop-pull technology to realize continuous multi-head casting. The utility model has the advantages of simple equipment, small investment, little metal loss and low environmental pollution procedure, etc. . Upper drawing continuous casting is generally suitable for the production of red copper and oxygen-free copper wire blank. The new achievement in recent years is its application in large diameter tube blank, brass and cupronickel. Up to now, an up-drawing continuous casting machine with an annual output of 5000 t and a diameter of over 100 mm has been developed, and two-component common brass and zinc-white copper three-component alloy wire billets have been produced, and the yield of wire billets can reach over 90% .

E other foundry techniques

The technology of drawing continuous casting tube blank is being developed. The invention overcomes the defects such as the slub mark formed on the outer surface of the billet during stop-pull process in up-drawing continuous casting, and the surface quality is excellent. And because of its almost directional solidification characteristics, the internal organization is more uniform and pure, so the performance of the product is also more excellent. The production technology of continuous cast red copper wire billet with wheel belt has been widely used in large production lines with 3-ton grade or above. The sectional area of Slab is more than 2000mm2, and the continuous rolling mill with back pass has high production efficiency. 

Source: Web Collation

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