At present, the taper values of high-efficiency copper mould tubes used by various steel mills are generally 0.6-0.9.
When the low-carbon steel and low-alloy steel are pulled, the taper value is taken as the middle and lower limit, and the drawn medium carbon steel and high carbon steel are the upper limit of the taper value.
In order to ensure that the inner cavity of the copper tube is consistent with the cooling shrinkage of the slab throughout the length of the crystallizer, the inner cavity of the crystallizer copper tube should be a parabolic continuous taper.
When casting low carbon steel and low alloy steel, the apex of the parabola should be designed at the lower end of the copper tube. At the same time, the taper distribution of the high-efficiency crystallizer should also match the other process parameters in the drawn steel.
The requirements for the taper of copper mold tubes for efficient continuous casting mainly involve the following aspects：
Importance of taper design
The taper design of copper mold tube is to ensure that the billet can be demoulded smoothly and maintain good surface quality during the continuous casting process.
Appropriate taper can reduce the friction between the billet and the wall of the crystallizer, and avoid cracks and other defects on the billet surface.
Taper range
Generally speaking, the taper range of copper mold tubes is usually between 0.5% and 1.5%. This means that the inner wall diameter of the mold tube gradually decreases from the top to the bottom.
The choice of specific taper depends on the type and size of the ingot and the specific requirements of the production process.
Factors affecting taper
- Bill type and size: Different billet types and sizes require different taper. For example, the taper of a slab and a billet may be different.
- Casting speed: High casting speeds usually require a larger taper to ensure that the billet can be demolded smoothly.
- Cooling efficiency: The design and efficiency of the cooling system will also affect the choice of taper. An efficient cooling system can remove heat faster and may require a different taper design.
- Material properties: Different metals and alloys have different thermal expansion coefficients and solidification characteristics, so the taper needs to be adjusted accordingly.
Examples of specific requirements
- Thin slabs: The taper is usually between 1.0% and 1.5% to ensure high surface quality and rapid cooling of thin slabs.
- Square and rectangular billets: The taper is usually between 0.5% and 1.0%, depending on the casting speed and cooling conditions.
The requirement for the taper of the copper mold tube for efficient continuous casting is to ensure that the ingot can be demoulded smoothly and has good surface quality and internal structure. This requires precise design and adjustment of the taper of the mold tube according to specific casting conditions and product requirements. By optimizing the taper design, the efficiency of continuous casting production and the quality of the ingot can be significantly improved.
