Automatic measurement of Centreline segregation in continuously cast line pipe steel slabs
Additional Publication Information
Centreline segregation appears as a positive segregation of alloying elements like C, Mn and P in the mid thickness region of continuously cast slabs. It is an intrinsic phenomenon for the casting process and it is almost impossible to mitigate through post processing. Centreline segregation can be harmful to the weldability and integrity of any fabricated steel product, especially line pipe. At present, there is no international consensus on evaluation methods of centreline segregation. A repeatable and objective method for evaluation of centreline segregation is highly desirable for both steelmaking process improvement and also for the prediction of final product performance. In the current work, a MATLAB program based on image analysis was developed to evaluate the images of centreline segregation by automatic measurement of segregation features. The original grey scale images of the centre line segregation were reduced to black and white images for automatic measurement. The black features of the image, representing areas of element segregation, were identified according to predefined criteria. The degree of segregation was evaluated based on equations which were developed by considering different parameters of the segregation segments, and also was evaluated by rules gleaned from experienced steelmakers.