Effective balancing of materials and costs
Overall reductions in aircraft weight are critical to the EU's green aircraft goals, since decreasing the weight of an aircraft has significant impact on fuel consumption and emissions. Titanium is the material of choice for critical aero engine components, but the high cost financially limits weight-reduction solutions for other parts of the aircraft. The use of thinner steel components is one way to reduce the cost of aero engine components without comprising quality. This frees up money for lightweight but more expensive materials in other places. However, conventional casting methods are not well-suited to producing large, thin-walled pieces. The EU-funded project 'Development of light-weight steel castings for efficient aircraft engines' (LEAN) investigated the use of an ancient and recently revived casting method, the investment casting or lost wax process. Investment casting is a complex, multi-step process. Wax is used to make a mould, which is melted and removed and then replaced by molten metal. After the metal hardens, the mould is broken to remove the final component. It enables the manufacture of complex geometries, very thin sections and very tight resolutions, making it particularly appropriate for the aerospace sector. Researchers carried out numerous casting trials to evaluate one common and several uncommon materials, two different geometries and two types of casting systems. The team assessed processing parameters and their effects on the fluidity of thin-walled investment castings. Scientists also evaluated the porosity and strength of cast products and compared experimental results to those of simulations. LEAN has significantly increased EU knowledge of the investment casting process for the production of thin-walled durable steel castings. Currently, the expertise regarding investment castings for the aerospace sector is much greater outside the EU than in it and, as such, the majority of such castings are produced outside as well. LEAN has laid the experimental and theoretical foundations for capturing an important share of that market sector.
