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

目的：了解电弧炉/薄板坯连铸生产适合高成形性钢规格（DX56+Z/DX57+Z）和包装钢应用的洁净钢的能力。背景：塔塔钢铁是全球领先的汽车和包装钢产品供应商之一，其未来的挑战之一将是使用新的炼钢、轧制和深加工技术生产具有良好成形性的涂层钢。新的工厂配置越来越多地通过电弧炉利用低碳炼钢，再加上使用薄板坯铸造技术的近净形铸造的进步。其优点是，它将开辟机会，充分回收废钢涂层回到新的涂层钢产品。因此，提高钢材的可回收性，这对综合工厂就渣中锌的影响提出了挑战。与传统厚板坯浇铸相比，该技术提供了许多经济和产品效益。缺点是板坯通常小于厚板坯连铸机厚度的25%，并且铸造速度快3-4倍，导致非金属夹杂物（nmi）被吸入钢中的风险更高。这些nmi对汽车和包装的高成形性涂层应用非常有害，其中产生的缺陷表现为分裂。这对我们的客户群来说是不可接受的。现有的技术可以通过显微镜和计算机断层扫描（CT）来评估钢基体。建议的活动：1)了解量化钢铁nmi的能力和技术。2)评估薄板坯铸造对钢材清洁度的影响。3)评估样品和工艺条件的影响。开发基于实验室的流程。5)评价nmi对涂层钢成形性的影响。6)评估nmi对涂层附着力的影响。7)评估使用高回收含量和先进铸造工艺制造高成形性涂层钢的可行性。

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.