20th International Forgemasters Meeting - IFM 2017

The remelting behavior of the hot-work tool steel X37CrMoV5-1 / H11, was investigated with several experimental melts on a lab-scale ESR-plant. The investigated parameters comprised a variation of the slag compositions and the use of a protective nitrogen atmosphere. Variations of the slag composition included slags with different contents of CaF2, CaO and Al2O3 as well as a variation of the SiO2-content in the slag. The remelted ingots were forged and analyzed regarding their chemical composition as well as their distribution and composition of the non-metallic inclusions (NMI) by automated SEM-EDX method. The chemical composition of the slag after remelting was analyzed as well. The results clearly show a clear relationship mainly of Si and Al in the steel with SiO2 and Al2O3 in the slag as well as the effect of oxygen in open ESR operation. Associated with these reactions are changes in the oxygen content. NMI changed in their total amount and size distribution as well as in the chemical composition. The SiO2-content of the NMI is significantly affected by the SiO2-content of the slag. The protective atmosphere reduced the Si-losses during remelting, but changed the composition of the NMI only slightly. The majority of the NMI were of the MA-spinel type. Variations of the CaO- and MgO-content of the slag shifted the composition towards Al2O3- or MgO-typ-inclusions. In General Remelting leads to an almost complete removal of sulfides, a reduction of oxisulfides and a slight increase of oxides.