Study on strip crossbow correction for uniform coating weight control
Abstract
In coating process of continuous galvanizing line, transverse crossbow is frequently found in the case of thick gage or high strength steel processing. This transverse crossbow arises due to the unbalanced residual stress distribution along the thickness, which is made by the elasto-plastic behavior that the steel sheet experiences during roll to roll transportation under continuous steel strip processing like surface cleaning and annealing. Because this crossbow makes the air knife to strip gap distribution uneven, it is difficult to get the uniform coating weight distribution along the transverse direction. In order to correct the crossbow of steel strip at the zinc coating position, correction roll displacement is used. While the mathematical model that calculates the crossbow curvature with theoretical and experimental background is introduced for the proper crossbow correction roll displacement determination, it is very difficult to guarantee the accuracy of its calculation because of many uncertain parameters that govern the model. In this study, a model adaptation method was developed to enhance the steel strip crossbow estimation accuracy using coating weight data and coating weight estimation model. This estimation method was applied to the classified operation results of many high strength steel and thick gage strip to verify the model estimation performance. The analysis of this application results shows the improved accuracy of the estimation model. Furthermore, future works for refining the developed model as well as the achievement with it will be discussed in this paper.
Citation
Jee, C. (2015, June). A study on strip crossbow correction for uniform coating weight control. Paper presented at the Thirteenth International Conference on Web Handling (IWEB), Stillwater, OK.