THE PROFILE 2017/18

Automotive industry/Lightweight construction/Aluminium

Fotos: AIT/ Johannes Zinner

The LKR is researching new aluminium alloys with optimized properties, which can be formed even better at cryogenic temperatures.

ICE COLD

FORMING

OF ALUMINIUM

The cryogenic sheet metal forming allows complex parts which have hitherto been made of sheet steel to be produced using aluminium. This reduces the weight of vehicles, for example.

OUR SERVICES

Recording and development of specific material model maps for light-weight materials at different load rates (stretching rates) and in various application areas

Requirement-specific minimisation of the weight of components and assemblies in order to achieve structural optimisation.

Material-compatible lightweight design for material substitution

Optimisation of topology, topography and robustness

Additive manufacturing methods and simulation for light metals

Crash and process simulation

Joining technologies

Prototype construction

Material and micro-structural simulation

Material characterisation for thermomechanical processes

Casting, e.g. low-pressure casting, squeeze casting, continuous casting and strip casting

Massive forming, e.g. rolling, extrusion, forging

Sheet metal forming, e.g. deep drawing, bending, active media based forming

OUR APPROACH

To increase energy efficiency and reduce emissions, the weight of a vehi- cle is the decisive factor for future mobility solutions. However, lighter materials must continue to meet the highest requirements of crash ma- nagement and structural design in order to guarantee vehicle safety. The reduction in the vehicle‘s weight is therefore crucial to reduce CO2 emissi- ons and to increase the range of purely electric vehicles. The LKR Leicht- metallkompetenzzentrum Ranshofen of the AIT Austrian Institute of Tech- nology is one of the leading international institutes and is developing de- sign methods which pay particular attention to the property profiles of light metals as well as specific manufacturing methods and resulting his- tories (e.g. residual stress profiles, warpage, uncertainties, etc.). A materi- al group that is attributed a particularly great potential in this respect is that of aluminium alloys. The formability of aluminium sheets is limited at room temperature. The state of the art is to form aluminium at elevated temperatures. In doing so, the microstructure is changed so that additio- nal processes are necessary to produce the desired sheet state.

REDUCING MANUFACTURING COSTS

As part of the research project „KryoAlu“, LKR scientists have therefore pursued an entirely new approach: The aim is to be able to form alu- minium better at low temperatures. This effect is to be used to lower production costs, but also to achieve more flexibility in production. To- gether with well-known companies from the metal and mechanical en- gineering industries, a process has been developed which enables forming at temperatures as low as –150°C. The sheet-metal plates are pre-cooled in liquid nitrogen, inserted into the forming press by a robot and removed again after the deep drawing. The tools are also cooled during this process.


SIGNIFICANTLY REDUCED MATERIAL USE

Complex parts which can be manufactured in this way reduce the use of materials significantly. The possible applications are wide-ranging. In theory, any deep-drawn, automotive aluminium sheet metal component could also be produced by cryogenic forming. The process is economi- cal where high demands are placed on component complexity with high strength and surface quality. Thanks to the high savings potential, the more expensive nitrogen treatment becomes economical. The KryoAlu project won the 2015 Upper Austrian Award for Innovation. And January 2016 then saw the launch of the successor project „KryoAlu2“. The fo- cus here is in particular on the industrial implementation of the process and the expansion of the range of materials. In KryoAlu2, the LKR is researching new aluminium alloys with optimized properties which can be formed even better at cryogenic temperatures.


PROVING SERIES-ORIENTED PROCESSES

The cryogenic sheet metal forming allows complex parts which have hitherto been made of sheet steel to now be produced using alumini- um. For example, several parts of a car door could be combined and manufactured as one part in order to reduce joints. This results in a tangible benefit for supplier companies which can offer a new segment of bodywork components in aluminium – and for the vehicle industry which can take a step towards achieving their emissions targets.


The involvement of voestalpine (with a focus on steel production and processing) impressively demonstrates the potential of this innovative method for the forming of aluminium in vehicle construction. The fur- ther substitution of heavier steel sheets – with lower energy consump- tion in production – seems possible. The long-term experience of the scientists in the field of materials science and their characterisation as well as in the thermomechanical treatment of the light metals alumini- um and magnesium helps LKR to optimally adapt the process solutions to the needs of the customers and project partners.

DI Andreas Kraly, Managing Direktor LKR: „With the completion of the successor project KryoAlu2, the development of tool cooling, lubrication and the corresponding alloys should be completed.“