Tailor-Made High-Performance Components: LZH Is Researching Laser Processes For Formable Hybrid Components

Only using expensive materials on high-performance components where they are really needed: That is the vision of the Collaborative Research Center 1153 "Tailored Forming". Scientists at the LZH are researching two laser-based processes.

Hybrid semi-finished products can save material and costs in production if only those parts of a component are made from a high-priced material that will be subject to high demands in later use and must therefore be particularly wear-resistant, for example. The Collaborative Research Center SFB 1153 "Tailored Forming" is developing a novel process chain for the production of load-adapted hybrid solid components, in which the semi-finished products are first joined and then formed. The LZH is researching two laser-based processes.

Formable semi-finished products manufactured by US laser beam welding
The joining and cutting of metals group was able to produce semi-finished products that can be formed without cracks using an ultrasound-assisted laser beam welding process. The scientists have welded shafts made of different mixed compounds such as steel-steel or steel-nickel and developed corresponding processes. The focus was on the question of how cracks can be avoided and which parameters in the welding process have which influence on quality features such as welding depth or seam elevation.

In the 3rd funding period of the Collaborative Research Center, the group would like to ensure more process stability through modulation of the laser power, among other things, and develop process control in order to achieve repeatable, reliable quality in the production of semi-finished products. In addition, the mechanical stresses in the component should be reduced by ultrasonic post-treatment.

Laser cladding takes into account local loads on components
The Machines and Controls group is continuing to research new types of components with local, load-adapted property profiles. To do this, the scientists used laser hot-wire build-up welding to apply a cost-intensive but high-strength material as a coating to component areas that are heavily used during operation. Tooth flanks of gears are just one example application. In this way, high-quality and hard coatings could be applied and the properties of the coating could be specifically influenced by the choice of materials.

In the next step, the group would like to develop process monitoring for quality assurance in build-up welding. For this purpose, the secondary radiation generated during the welding process is to be measured with a special sensor and analyzed using machine learning methods in order to be able to derive a prediction of the coating properties. The goal: Non-destructive quality control of the coatings directly during the process.

About The SFB
The work of the LZH is part of the Collaborative Research Center SFB 1153 "Process chain for the production of hybrid high-performance components through tailored forming", in which experts from nine institutes of the Faculty of Mechanical Engineering at Leibniz Universität Hannover, from the LZH and the Institute for Integrated Production Hannover (IPH) are working on developing new process chains for the production of hybrid components.

Within the SFB, the LZH is working on the sub-project A03 "Ultrasonic-assisted laser beam welding to produce formable mixed joints", together with the Institute for Dynamics and Vibrations (IDS) , and the sub-project A04 "Local adaptation of material properties on forming blanks by build-up welding to produce graded hybrid components", together with the Institute for Materials Science (IW) .

The SFB started work in July 2015. The 3rd funding period runs over 4 years and starts in July 2023. It is funded by the German Research Foundation under the funding number 252662854.

More information on the Collaborative Research Center 1153 is available on the Leibniz Universität Hannover website (https://www.sfb1153.uni-hannover.de/de/).