Steps towards sustainability and decarbonisation - impact of high recycled content and advanced casting on high formability products

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Objectives: To understand capability of EAF/Thin Slab Casting to produce clean steel suitable for high formability steel specifications (DX56+Z/DX57+Z) and Packaging steels applications. Background:Tata Steel is one of the leading global suppliers of automotive and packaging steel products and one of its future challenges will be to produce coated steels with good formability using new steelmaking, rolling and further processing technology. There is growing movement for new plant configurations to utilise low carbon steelmaking via an EAF coupled with the advancement of near net shape casting using thin slab casting technology. The advantage is it will open up opportunities to fully recycle coated steel scrap back into new coated steel products. Thus improving the recyclability of steels which pose challenges to integrated plants with regards to the impact of zinc in slag waste. This technology offers a number of economic and product benefits over traditional thick slab casting. The downside is the slab is typically less than 25% of the thickness of a thick slab caster and casting speeds are 3-4 times faster leading to a higher risk of non-metallic inclusions (NMIs) being drawn into the steel. These NMIs are highly detrimental to high formability coated applications for automotive and packaging where the resultant defect manifests as splitting. This is unacceptable to our customer base. Techniques exist to evaluate the steel substrate through microscopy and computerised tomography (CT) scans.Proposed Activities: 1) Understand capability and techniques to quantify NMIs in steel.2) Evaluate impact of steel cleanliness from thin slab casting.3) Evaluate samples and impact of process conditions.4) Develop lab based process.5) Evaluate impact of NMIs on formability of coated steels.6) Evaluate impact of NMIs on coating adhesion. 7) Evaluate feasibility to make high formability coated steels using high recycled content and advanced casting processes.