WarmAp – Subproject: Investigation of Friction and Wear in the Hot Forming of high-strength Aluminium Alloys
The research project described below is part of the SME collaborative project WarmAp within LOEWE's ALLEGRO focus and is being carried out as a dual PhD position with Filzek TRIBOtech.
Aluminium has made important contributions to resource-efficient lightweight construction for decades. Applications can be found in the aerospace and automotive industries as well as in high-quality equipment for cycling, outdoor and alpine sports. The trend towards electromobility is currently creating new challenges in terms of weight reduction and suitability for mass production. These challenges cannot be solved satisfactorily with existing alloy and production concepts.
This is where the “WarmAp” project comes in: The core of the project is to further develop the limited know-how on hot forming of aluminium and to implement it in an industry-oriented environment. Hot stamping generally promises increased forming capabilities and thus the possibility of producing highly complex aluminium components. Research is also being conducted to locally adjust the material properties (e.g. strength and hardness) within a component. This adjustment is optimally energy-efficient by means of a locally controlled cooling process in the forming die (also called cold die quenching, see Fig. 01).
Tribology is a central research topic in the further development of aluminium hot forming processes. The analysis and prediction of friction and tool wear under various tribological conditions is essential for the successful industrial implementation of these processes. With the test benches used so far, no satisfactory investigation of friction and tool wear in the hot forming of aluminium is possible.
The aim of the project is to carry out process-related strip drawing tests in order to obtain information on the friction and wear behaviour during hot forming of high-strength aluminium alloys. Based on the test results, the construction and validation of a wear model is planned, which can be used in FE simulations of forming processes.
A strip drawing machine is already in use at PtU for process-related friction and wear measurement in cold forming (see Fig. 02).
The further development of this facility is planned until the end of 2019 in order to use it for the above-mentioned investigations. For this purpose, the system is extended by the elements and functions shown in principle in Figure 03. After completion of the system expansion, different lubricants are tested under different process conditions (temperature, normal contact stress, tool coating, etc.). A suitable wear model is derived from the gained knowledge. This wear model is validated in real forming tests in associated work packages of the Allegro overall project.
As part of the plant expansion and test implementation, a number of challenging student projects are offered. Thematically, the focus of the work can be adapted to the strengths and interests of the students. Furthermore, the overall project offers potential for “HiWi” activities with experimental and constructive activities, as well as literature research and theoretical considerations.
This project (HA project no. 548/17-30) is funded in the framework of Hessen ModellProjekte, financed with funds of LOEWE – Landes-Offensive zur Entwicklung Wissenschaftlich-ökonomischer Exzellenz, Förderlinie 3: KMU-Verbundvorhaben (State Offensive for the Development of Scientific and Economic Excellence).
We thank the Hessenagentur for financing the research project. We would also like to thank the companies involved in the WarmAp collaborative project, in particular Filzek TRIBOtech, and all those involved at ALLEGRO for their excellent cooperation.