9th ECCC European Continuous Casting Conference – ECCC 2017

Producers of cast products are in duty to their customers to document the inner quality of the product. The ultrasound measuring is a widely known and well-established technique for non-destructive analysis of the inside of a material used in medicine and many other fields. Every women being pregnant appreciates that very much being able to get the situation of her unborn baby without any big effort to be taken. In the steel industry, ultrasound testing is already used to evaluate the internal quality of as-rolled material. The ultrasound measurement technique of HD scan for the evaluation of internal quality defects in the cast product sample is environmental friendly and needs a less surface processing in comparison to the etching procedure. The clean and safe technology offers three-dimensional views into the sample, providing higher representative information for a better quality evaluation. The quality evaluation is done automatically and based on clear statistical rules. Size and distribution of the segregation are used for a segregation classification. Cracks statistics and narrow side profile contour determination are being realized too. The accuracy of this method is proven by parallel metallographic investigations. Automatic defect determination and classification is compared with macro-etching classification results on more than 100 samples of different cast products. Macrostructure visualization is possible even for samples that do not succeed by macro-etching. Areas of equiaxed and columnar crystallization can be distinguished and quantitatively determined. All this is beneficial for the optimization of cast parameters, such as strand shell cooling, soft reduction or mold and strand stirring. The ultrasound quality evaluation system offers reliable and objective quality results fully independent of etching parameters and subjective quality operator impressions. The hitherto existing etching method may be completely replaced or the number of etching tests will significantly be reduced.