Development of Roll Formable Ultra High Strength Steels for Energy Efficient Manufacture of Lightweight Crash Resistant Automotive Structures

该项目涉及超高强度钢（UHSS -极限抗拉强度大于1000mpa的钢）的开发，特别设计为一种新型的低能量和柔性制造工艺，称为3D滚压成型，为汽车行业生产轻质抗碰撞结构。与传统的冲压工艺相比，滚压成形工艺是一种渐进的弯曲工艺，可以将平面板材转变为结构轮廓，而传统的冲压工艺则需要对板材进行严格的拉伸以创建所需的零件几何形状。3D滚压成形工艺非常灵活——该技术的领先开发人员声称，一套工具可用于制造多达四分之一的汽车结构，而冲压工艺则需要为每个单独的零件制造一套昂贵的工具。此外，与冲压生产线18个月的安装时间相比，一条滚压成型生产线只需要10到16周的安装时间。目前，超高强度汽车用钢通常采用能源密集型热冲压成形，因为要设计出达到所需的高室温均匀延展性和超过1000兆帕的极限拉伸强度的钢是非常困难和昂贵的。由于辊压成形只要求材料可弯曲，因此建议采用低加工硬化率和高屈服比（屈服强度/极限抗拉强度）的钢适合使用该工艺进行成形。用于辊压成形的超高压合金的发展允许更简单的成分，更精简，具有更低的合金成本，从而减少了对原材料供应问题（稀缺性）的暴露，与现有能力具有更好的兼容性，并且更加一致（更高的产量/更低的废品率）。这是一项潜在的颠覆性技术，可能会彻底改变汽车结构件的制造。它将：消除目前用于成形超高频钢的能源密集型热冲压的需要；大大减少模具的要求和能源相关的制造；提高材料利用率；避免使用Al， Mg和CFRP等能源密集型材料进行轻量化；同时生产的产品将在使用过程中产生大量的二氧化碳。据估计，如果轧制成形钢取代50公斤的热冲压部件在一辆车，那么在英国汽车制造业每年可以节省40,000吨二氧化碳。

This project is concerned with the development of Ultra High Strength Steels (UHSS - steels with a ultimate tensile strength greater than 1000 MPa) specifically designed to be formed by a novel low energy and flexible manufacturing process, known as 3D roll forming, to produce lightweight crash resistant structures for the automotive industry. The roll forming process is an incremental bending process that turns a flat sheet into a structural profile as compared to traditional stamping processes that involves severe stretching of the sheet to create the required part geometry. The 3D roll forming process is extremely flexible - leading developers of the technology claim a single set of tooling can be used to manufacture up to a quarter of the automotive structure, whereas the stamping process requires an expensive set of tools to be manufactured for each individual part. Furthermore a roll forming line only take 10 to 16 weeks to setup as compared to 18 months for a stamping line. Today ultra high strength automotive steels are usually formed using the energy intensive hot stamping as it is very difficult, and costly, to design steels that achieve the required high room temperature uniform ductility in combination with an ultimate tensile strength in excess of 1000 MPa. As roll forming only requires the material to be bendable, it is proposed that steels with low work hardening rates and a high yield ratio (yield strength /ultimate tensile strength) could be suitable for shaping using this process. The development of UHSS for roll forming allows simpler compositions that are leaner and have a lower alloy cost which reduces exposure to raw materials supply issues (scarcity), have better compatibility with existing capabilities and are more consistent (higher yield/lower scrap). This is potentially a disruptive technology that could revolutionise the manufacture of automotive structural members. It will: eliminate the need for energy intensive hot stamping currently used for shaping UHSS; dramatically reduce tooling requirements and the energy associated in their manufacture; increase material utilisation; avoid the need to use energy intensive materials for lightweighting such as Al, Mg and CFRP; all whilst producing a product that will yield significant CO2 savings during use. It is estimated that if roll formed steel replaced 50 kg of hot stamped components in a vehicle, then 40,000 tonnes of CO2 could be saved in the UK automotive manufacturing industry per annum.