THE INFLUENCE OF DIFFERENT MELTING AND REMELTING ROUTES ON THE CLEANLINESS OF HIGH ALLOYED STEELS

摘要

The cleanliness of steel has an essential impact on many properties like corrosion resistance or toughness. Beside the deoxidation treatment, remelting or even multiple remelting strongly influences the cleanliness and can result in huge improvements. After a rough overview on measurement methods and the melting and remelting facility at Bohler Edelstahl, this work first shows typical cleanliness results according to the ASTM E4S measurement of two different steel types taken from standard production. The investigated steels range from hot work tool steel to austenitic stainless steel covering also different kinds of deoxidation procedures. Furthermore the differences of various melting and remelting routes are described and compared to each other, including the process routes EAF, EAF+ESR, EAF+PESR and EAF+VAR. Additionally, the morphology and composition of the different inclusion types found in the investigated material are described and compared.