Approach for Increasing the Resource Efficiency for the Production Process of Titanium Structural Components

Abstract

Titanium structural components for the aircraft industry are usually manufactured from ingots of primary material. The process chain for the fabrication of these components consists of the production of titanium sponge, the melting process, the forging process and the milling process. High chip removal rates from up to 95% due to the milling process and a high energy demand in producing the titanium sponge of about 85% of the overall energy consumption characterize the process chain. This obviously leads to a high optimization potential under monetary and energetic aspects. Recycling titanium chips for the ingot production could help to dramatically improve the overall production process in terms of ecological aspects. However, process-induced contaminations of the chips prevent the use of high amounts of these in the melting procedure. Macroscopic impurities like residues of cooling lubricant can be removed in a complex cleaning process. Yet, contaminations like oxidization cannot be eliminated, hence only a small amount of titanium chips is usable in the melting process to achieve the required purity of the titanium alloy. This paper describes a novel method to decrease the energy consumption in fabricating titanium products. By reducing process-induced contaminations, the amount of titanium chips usable in the melting process can be significantly increased and consequently the necessary quantity of titanium sponge reduced. The described method contains the investigation of relevant influencing factors like the impact of tool and cooling concept on chip quality or manufacturing costs. The research of cause-effect relationships identifies the trade-off between ecological and economic targets. A mathematical description of this relationship is implemented within a simulation environment to find an optimum between ecological and economic targets. The paper describes this approach with samples of the titanium alloy Ti6Al4 V.