THE EFFECT OF DEOXIDATION PRACTICE ON NON-METALLIC INCLUSIONS AND THEIR EFFECT ON MECHANICAL PROPERTIES OF A LOW ALLOY STEEL

In the present work, the characterisation of a low alloy steel produced for structural applications is presented. The steel was fabricated via two different deoxidation practices; conventional Al killing and a proposed Si-Al killing technique. The casting method employed was continuous casting and material from different heats was analysed. Their respective inclusion contents were assessed in the as-cast and as-deformed conditions. The imaging methods included manual and automated imaging by optical microscopy and Scanning Electron Microscopy. Steel fabricated via the aluminium killing practice, contained less inclusions per mm2 but more alumina and calcium aluminates compared to the Si-Al killing practice, which contained more inclusions per mm2 but exhibited a higher percentage of manganese sulphide type inclusions. The mechanical properties of material in the as-deformed condition were assessed, according to standard specification requirements.