ABSTRACT: Electrical Copper Bar is a kind of high current conductive copper, used for high and low voltage electrical appliances, switch contacts, distribution equipment, bus slot and other electrical equipment, also widely used in metal smelting, electrochemical plating, chemical caustic soda and other ultra-high current smelting or electrolytic equipment; cross-section shape of 4 rounded corners have technical requirements of the rectangular section; with mechanical properties and conductive properties. 1. Copper bar electrical copper bar is a high current conductive copper, used for high and low voltage electrical appliances, switch contacts, distribution equipment, bus slot and other electrical equipment, also widely used in metal smelting, electrochemical plating, chemical caustic soda and other ultra-high current smelting or electrolytic equipment; cross-section shape of 4 rounded corners have technical requirements of the rectangular section; with mechanical properties and conductive properties. 2. Copper bar production technology copper bar production technology is mainly divided into the traditional rolling and extrusion two processes, process flow, complex procedures, energy consumption, low material utilization. A. Large Ingot hot rolling coil-high precision cold rolling method: LARGE INGOT hot rolling coil, mature technology, hot rolling can fully change the casting structure, but the process flow is long, equipment investment is big. B. Horizontal continuous casting coil-high precision cold rolling method: Horizontal or upward continuous casting coil, short process flow, less equipment investment, residual cast structure after cold rolling, low yield due to milling. Continuous extrusion process: The new continuous extrusion process can combine the advantages of the above two processes, product Grain Organization (comparable to Hot Rolling Organization) , short process, high yield, equipment plant investment, reduce the threshold into the industry. 3. Advantages of continuous extrusion process: Using continuous casting and rolling wire rod as raw material, convenient supply, no extrusion surplus, high material utilization, generally up to 95% , good uniformity of microstructure and properties. Continuous extrusion uses the heat generated by friction to increase temperature without heating, thus saving energy. Less working procedure, high production efficiency and high rate of finished products. Continuous production of products without interval of time. The traditional processing methods for super-long products usually do not exceed 30-50m, while the continuous extrusion method can be used for long products ranging from several kilometers to tens of thousands of meters. 4. Typical application of continuous extrusion:-Manufacture of cooling pipe for Cable Television coaxial Cable Outer Conductor, Communication Cable Sheath for aluminum-clad Steel Wire manufacture-manufacture of copper alloy contact wire for high-speed railway manufacture of flat copper wire and copper bar for oxygen-free copper bars, ultra-wide row continuous extrusion production: continuous extrusion width is limited, the main reason width range is 300mm, key technical problems: how to fill the cavity, how to ensure the uniformity of flow velocity in the process of Strip extrusion. 5. The Solution: Start with the preheating temperature of the billet, the setting of the die parameters and the rational selection of the power of the extruder to explore the design of the die cavity, the microstructure and properties after extrusion:-The structure after continuous extrusion is recrystallized and has no flowing line structure in plastic forming; the structure is uniform and small, the surface is smooth and smooth without oxidation, and it can be directly processed by subsequent rolling without surface treatment; The hardness of copper after extrusion is about HV60-70, which belongs to soft state and suitable for subsequent large deformation calendering. 6. The recommended technological process is as follows: Top drawing → extrusion → rolling → annealing → drawing blank rolling quantity is limited, the thickness of rolled semi-product is more than 2 mm, it can be satisfied by using two-high rolling mill, and the function waste can be avoided. Hollow cross-section Conductor Bar (profile) continuous extrusion manufacturing: Hollow cross-section Copper Bar (profile) widely used in electronics, power and other fields, multi-air cross-section bar production difficult, expensive, difficult to see the market. Traditional-hollow billet piercing extrusion method: Can only produce a simple shape, large size (diameter of 50mm or more) ; for thin-walled, small hole, long profile production difficulties. Traditional-stretching method: mainly produces the wall thickness uniformity of the hetero-tube, to the wall thickness non-uniformity hetero-tube, is difficult to realize, also is not economical. International leading production technology: Wide Row continuous extrusion-straight row extrusion, first bending straight and hollow row continuous extrusion. 

Source: SMM PUBLISHER: Xiesh