Validation of the process stability of the manufacturing route for light metal structural components based on closed titanium alloy material cycles
Project TiReGo
New melting technology for sustainable Ti6Al4V miniingots
Goals
As part of the HWH sub-project, the melting metallurgical process route for the production of Ti6Al4 is to be fundamentally developed with the necessary processes of raw material compaction, melting and casting using a new and combined plasma-arc melting / cold-wall induction melting technology. This also includes adapting the chemical composition of the alloy with grain-reducing additives to the requirements of the aviation industry.
The new process is intended to enable the direct use of cast material as a forging starting material. The starting point of the innovation proposed here is a single-stage melting and casting technology for the production of small-scale Ti6Al4V ingots (diameter ≤ 200 mm), which are suitable for direct use as forging material due to their fine cast structure. By incorporating a closed Ti6Al4V recycling route, the material and resource efficiency of the manufacturing process can also be significantly increased. The focus here is on the development of a process route for the use of primary material and recycled material, the design of the plant concept, the coordination of the die design, the addition of grain refining agents and the adjustability of the material microstructure.
Brief description
Within the project, HWH is responsible for the production of the mini-ingots in the single-stage melting process and for the selection, definition and remelting of the available recycled material for direct recycling. This includes defining the entire process route for the use of primary material and recycled material for the production of aviation-certified semi-finished products with the project partners. To this end, concepts for melting and setting up the recycling route for series use are developed together with the project partners. Once the process route has been defined, the individual plant concepts will be designed, in particular the construction of a new cold mandrel induction mold with a diameter of approx. 200 mm for the production of the mini ingots. In addition, the feeding of lumpy recycling material into the melting furnace is designed. In the concept phase HAP1, the first mini ingots are produced on an existing mold design with a diameter of 120mm. This includes selecting the raw materials and adjusting the casting parameters in order to produce the most homogeneous and fine structure possible in the ingot. The standard casting microstructure in existing process routes is very coarse for the Ti6Al4V alloy. By using the new SinglePAM furnace technology with inductive continuous casting mold and by combining it with the addition of grain refining agents in HWH, the microstructure can be significantly influenced in order to achieve the necessary homogeneity and grain size in the microstructure. In the implementation phase HAP2, the findings of HAP1 are transferred to the industrially relevant ingot size (ᴓ 200mm). In WP2.1, ingots are initially produced from primary material. In addition, the feed for lumpy recycling material is implemented in WP2.5. The recycled material comes from the forging processes at Otto Fuchs and is cleaned and prepared accordingly by HWH in order to feed it back into the process. In WP2.6, ingots are then produced from recycled material. In HAP4, the new production route is evaluated in terms of the energy/CO2 balance and manufacturing costs. This evaluation will also include a plant concept created specifically for these applications.