Effects of Guide Arc Radius in a Continuous Casting Machine
The continuous casting machine is the dominant production process for manufacturing steel and other alloys. The arc radius of the guide has a great influence on the quality of the product and the process performance. The guide arc radius influences several variables and it will be discussed in this paper.
The guide arc radius influences the speed of the solidification process affecting the surface quality. A larger radius will lead to slower solidification and, therefore, smoother and stronger material. Slower solidification will also increase the chances of an inclusions free product. With a smaller arc radius, the solidification rate will be higher and the product will be lighter and more prone to porosity.
The arc radius also affects the time of contact with the moving strand. This influence will directly affect the temperature of strand during the solidification process. With a smaller radius, the contact time with the moving strand will be shorter and, therefore, the temperature potential difference will be higher. A larger radius will mean a longer contact time of the strand with the moving hot strand, thus reducing the temperature potential difference between the cold strand and the hot strand and the opportunities of creating a quality product.
The arc radius affects the accuracy of the guide. Smaller radii, because of their curvature, create more side force that generates higher resistance to the guide. This generates the need for more adjustments, due to the pressure of the guide on the strand, affecting the accuracy of the guide. Bigger radii reduce the amount of side force, reducing the pressure of the guide on the strand, thus improving the accuracy of the guide.
The arc radius affects the thermal balance of the strand. Smaller radii will create colder points in the strand due to the contact of the guide with the strand. This will affect the top temperature of the strand, leading to colder top temperatures and, therefore, more material movements. Bigger radii reduce the amount of contact with the guide, reducing the differences in temperature along the strand and assuring a more thermal balance along the strand.
Finally, the arc radius affects the loss of enthalpy of the strand. Alloys and metals come with a certain level of enthalpy that is lost during the solidification process. A larger arc radius will lead to a slower process and, therefore, a lower loss of enthalpy. Smaller radii, on the other hand, will lead to a faster process and a greater loss of enthalpy.
To conclude, the arc radius of the guide will have a direct impact on several variables of the solidification process, such as the speed of solidification, the temperature potential difference between the strand and the guide, the accuracy of the guide, the thermal balance of the strand and the amount of enthalpy lost during the process. Adjusting the arc radius to the required values will assure a better quality product and a better process performance.
