Laser Welding Will Revolutionize Steel Structures

Energy and resource efficiency are becoming more and more important, which is why Germany's Fraunhofer Institute for Materials and Beam Technology (Fraunhofer IWS), together with partners, is developing an alternative to conventional steel construction, which not only constitutes a process technology solution but also Forms the foundation of hardware and laser safety. This solution facilitates gentler processing of high-strength materials, significantly reduces energy consumption and costs, and increases processing speed. Compared to conventional joining processes, the energy input required by the components can be reduced by up to 80%. In addition, the parts made by the new process do not need to be straightened during subsequent processing.

Many technical structures employ some form of steel construction. Whether it's a container ship, a rail vehicle, a bridge or a wind turbine tower, any of these structures has hundreds of meters of welds. In the past, most of these welds used conventional processes such as metal active gas welding or submerged arc welding. But due to the low arc strength, most of the energy dissipated is not used in the welding process, but is lost to the component in the form of heat.

The energy required for post-weld processing is often similar to the energy required for the welding process itself. In this regard, Dr. Dirk Dittrich, head of the laser beam welding group at Fraunhofer IWS, emphasizes that this energy-intensive process can cause severe thermal damage to the material and lead to severe deformation of the structure, after which the part can only be restored by a costly straightening process .

Powerful laser welding process

A team of researchers led by Dr. Dittrich and partners have developed an energy-efficient alternative as part of the project "VE-MES - Energy Efficient Low Distortion Laser Multipass Narrow Gap Welding". Laser Multi-Pass Narrow Gap Welding (Laser MPNG) uses a commercially available high-power laser and differentiates itself from traditional methods due to the reduced number of layers and a significantly reduced number of welds.

Depending on the component, we can reduce energy consumption during welding by up to 80%, compared to filler material consumption by up to 85%. Dr. Dittrich said. As a result, this process can reduce production time and costs, process high-strength steel and achieve low-carbon production. Given that Germany and around the world will still require large amounts of steel in the future, this process will appear very There are advantages.

Because the high intensity of the laser beam ensures that the energy input is highly concentrated on the weld point, the surrounding area of the component remains relatively cool. Welding time is reduced by 50-70%. The new process is also equally good in terms of weld quality, with thinner welds and almost parallel edges, compared to the V-shaped seam in conventional welding processes. If laser welding is used in the steel structure process, it will become a unique selling point for German medium-sized companies and consolidate their market position in international competition.

The research team is providing the industry with an efficient welding technology that will revolutionize steel construction due to its cost-effective application and resource-efficient production process.

Using a practical example of an indoor crane component, researchers at Fraunhofer IWS demonstrate the newly developed performance. They deploy new welding techniques using special system technology and integrated beam protection. According to the experimental design, the four-meter-long rectangular profile of the indoor crane meets the design and manufacturing requirements of conventional production components. Produces typical application welds: butt joint on 30mm board and fully connected T-joint (15mm).

For a 1m weld, the cost of 30mm plate thickness can be reduced by 50% compared to submerged arc welding, including the subsequent straightening process. For sheet thicknesses less than 20mm, the potential cost savings can even be as high as 80% compared to the metal active gas welding process. For large companies, welding filler material alone can save more than €100,000 per year in costs. Furthermore, the laser sources used have a great potential to prevent rising energy costs due to their high efficiency (about 50%) and good process efficiency (80% reduction in energy consumption). With this evidence of practical applicability, the method can now be extended to other applications.