For numerous seam and joint configurations, laser welding represents the most productive and reliable method for high-strength-substance bonds of metallic components. The Fraunhofer Institute for Laser Technology ILT develops tailor-made processes, tools and systems for laser beam welding applications.
The spectrum of laser welding extends from heat conduction welding to deep-penetration welding, a keyhole process in which aspect ratios of up to 10:1 are attained. High power densities permit a concentrated energy input, achieving high welding speeds as well as significantly reduced heat influence and distortion. Compared with arc welding, it allows a much wider range of materials to be welded, and material thicknesses of up to approximately 20 mm can be welded in one pass.
Hybrid welding efficiently combines the deep-penetration mode of laser beam welding with the advantages of arc welding. The laser beam and arc work together in one process zone. The welding speeds, that are characteristic of laser welding, are complemented by high gap-filling ability. Optimal adjustment of the process to the material being welded produces welds with excellent fatigue strength.
The combi-head enables cutting and welding to be performed in one setup. The parameters are adapted for the change in process by numerical control. The use of auxiliary energy (heat, ultrasound, electric or magnetic fields) makes it possible to join materials which normally are presumed not to be suitable for welding and to produce weld seams with particular characteristics.
Fraunhofer ILT conducts research not only into the behavior of steels and aluminum alloys but also into laser beam welding of titanium and titanium alloys. Our research scientists possess extensive experience in the laser welding of nickel-based alloys and advanced austenitic and martensitic high-temperature steels. Current research work is focused amongst others on chromium steels with martensitic microstructure, aluminide-based alloys and non-ferrous metals, as well as the welding of dissimilar materials.
To reduce the occurrence of defects in welds and failures in welding processes, we conduct damage investigations as well as fault tracing and examine production processes. If it is not possible to remedy defects on the customer’s installation, the fault mechanisms are determined by experimental replication in our laboratory and the process is readjusted and optimized. A metallography laboratory, optical and interference microscopes and two scanning electron microscopes are available for ad hoc analyses. We undertake extensive materials testing in conjunction with specialist partners.
We provide our customers with comprehensive support in the procurement, installation and conversion of laser systems, with a particular emphasis on the development and optimization of processes and techniques. Our range of services in laser welding extends from the verification of weldability and the manufacture of test samples to prototype production.
Fraunhofer Institute for Laser Technology ILT
