Assessment of the Influence of Electro Slag Remelting on the Purity and Mechanical Properties of Structural Steel

Electro slag remelting steel is a technology of tertiary metallurgy that can be used in the production of special structural steels where high purity is required to influence the quality of the final products. This work deals with the evolution of steel purity comparing vacuum degassing (VD) and electro slag remelting (ESR) technologies in terms of the chemical composition of non-metallic inclusions and their morphology. The present work primarily studies the creep behavior of special structural steel at two different initial material states (VD and ESR steel) tested in the range from 450 to 650 °C. A rather unique plastometric experimental methodology of accelerated creep testing, which consists of a slow plastic deformation of a material under long-term stress at an elevated temperature, was used to study the behavior of the prepared specimens. The results show that, after remelting the steel, there was an increase in micropurity due to a reduction in the average size and, in particular, a reduction in the maximum size of non-metallic inclusions. The results of creep behavior show a particular difference at 600 °C, where ESR steel shows higher relaxation phase stress values as well as higher creep strength factor values compared with VD steel.