Square copper tube - the determining factor of the choice of crystal tube material

Since the inside of the copper tube is in contact with the high-temperature molten steel, the temperature difference between the inner and outer surfaces of the copper tube is large, the thermal stress is high, and the steel tube is highly susceptible to denaturation. The shape of the inner cavity of the copper tube is very important. To protect the shape of the inner cavity of the copper tube and the appearance of the crystal solidified shell, the air gap can be made small and uniform. Therefore, the copper tube material is required to have strong heat deformation resistance, that is, the requirement High recrystallization temperature, small thermal expansion coefficient, good thermal conductivity and high thermal fatigue strength.

The choice of copper tube material is developed along the direction of copper→phosphorus deoxidation copper→silver copper→chromium zirconium copper. Since the recrystallizer temperature of chromium zirconium copper is the highest among the above materials, its thermal deformation resistance is the strongest. However, due to its high cost, there are problems such as large amount of copper tube rebound in the extrusion process. At present, there are not many domestic copper tube manufacturing.