Thermal control and uncertainty evaluation of thermo-mechanical properties of materials for industrial hot stamping productions

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Almost one third of the UK's major contributions to net greenhouse emissions are from the automotive industry and road transport, and a quarter of the carbon footprint is from the materials sector. Lightweight design of vehicles is crucial in contributing to reducing CO2 emissions, by using materials appropriately, developing intelligent manufacturing technologies, and improving production practices, such as in hot stamping. The data-driven manufacturing industry requires multi-directional performance of materials to be measured by a specialised method, called multi-axial testing, to stretch a piece of material under real life conditions until fracture, given that most of engineering materials are anisotropic. By using material multi-axial data and virtual prototyping - the typical integrated simulation technology used for designing/manufacturing lightweight car parts, enables a reduction in cost and time in low carbon manufacturing.Existing material multi-axial thermo-mechanical testing methods are complicated, costly, and cannot be readily applied for testing at high temperature. New measurement instrumentation, algorithms, and methods for material characterisation under real manufacturing conditions, have been developed at Multi-X, a spin-off of Imperial College London, to overcome the bottleneck of the lack of material formability data to quantify complicated straining states under hot stamping conditions, and to improve the energy efficiency of product design and manufacture.Within the project, contactless measurement of the temperature distribution delivered by the state-of-the-art equipment at NPL will be implemented in the Multi-X's testing process. It will enable monitoring of the thermal history and spatial uniformity of temperature field for accurate characterisation of material multi-axial thermo-mechanical properties. An uncertainty analysis of the measured temperature and material properties will be performed to demonstrate the reliability and robustness of the Multi-X's innovative testing method. Multi-X has conducted a range of multi-axial tests for end-users, covering boron steel and aluminium alloys that are commonly used in hot stamping production of lightweight car parts. This project will concentrate on the thermal assessment of aluminium alloys up to a temperature of 550 °C.A successful project outcome will improve the quality assurance of the leading material thermo-mechanical testing technology, with the ultimate aim to exploit this UK-invented technology to enable cost-effective manufacture of lightweight car components. Multi-X's technology has the potential to be applied in a wide range of other sectors, including aerospace, train, bioengineering, etc., to further develop the market. Additionally, it can be applied to measure multi-axial properties of other materials, e.g., titanium, magnesium, composite, tissue, textile.