Forum for Science, Industry and Business

Thick metal sheets? Laser welding!

The processes for joining maritime steel components have a great development potential in terms of production costs and productivity: the frequently used submerged arc welding is comparatively slow and involves significant workpiece distortion. Laser-arc hybrid welding, as an alternative process, requires labor-intensive edge preparation and is not very flexible.

The aim of the DIOMAR project is to establish new laser welding processes based on high-power lasers in the maritime sector. (Photo: © MEYER WERFT / I. Fiebak)

Particularly for large steel sheet thicknesses in the range of 12 millimeters to 30 millimeters, no method has been able to prevail against submerged arc welding.

The scientists at the LZH now want to change this together with their partners Meyer Werft GmbH & Co. KG, Held Systems Deutschland GmbH and Laserline GmbH.

Robust, pure laser welding processes

The scientists want to develop robust, pure laser welding processes, especially for thick metal sheet welding in the maritime sector. For this purpose, the project partner Laserline will realize new diode laser beam sources with a maximum output power of up to 60 kilowatts in continuous-wave mode.

The aim of the project is to achieve high-quality joints with high welding speeds. The partners want to reduce the costs for edge preparation and the amount of additional material compared to existing joining methods. In that way, the costs shall be reduced eventually. The new processes shall complement or even replace the existing ones.

The application-oriented development takes place in parallel in a laser laboratory and in a shipyard-like test environment. This makes it possible to quickly test, evaluate and optimize processes.

Focus on laser safety

The partners are particularly keen to develop concepts for ensuring laser safety for very high laser output powers of up to 60 kilowatts. This includes the handling of the expected large quantities of emitted hazardous substances. To this end, the LZH also comprehensively investigates the release of hazardous substances from the laser processing zone.

About DIOMAR

The joint project "Thick Metal Sheet Welding by High-Power Diode Lasers for Maritime Applications" (DIOMAR) is being carried out by Meyer Werft GmbH & Co. KG, Held Systems Germany GmbH, Laserline GmbH and the LZH. DIOMAR is funded by the Federal Ministry for Economic Affairs and Energy.

Lena Bennefeld | Laser Zentrum Hannover e.V.
Further information:
http://www.lzh.de/

Im Focus: A golden age for particle analysis

Process engineers at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) have developed a method which allows the size and shape of nanoparticles in dispersions to be determined considerably quicker than ever before. Based on gold nanorods, they demonstrated how length and diameter distributions can be measured accurately in just one step instead of the complicated series of electron microscopic images which have been needed up until now. Nanoparticles from precious metals are used, for example, as catalysts and contrast agents for diagnosing cancer. The results have been published in the renowned journal Nature Communications (doi: 10.1038/s41467-018-07366-9).

Even in the Middle Ages, gold particles were used to create vibrant red and blue colours, for example to illustrate biblical scenes in stained glass windows....

Im Focus: Successful second round of experiments with Wendelstein 7-X

The experiments conducted from July until November at the Wendelstein 7-X fusion device at the Max Planck Institute for Plasma Physics (IPP) in Greifswald have achieved higher values for the density and the energy content of the plasma and long discharge times of up to 100 seconds – record results for devices of the stellarator type. Meanwhile, the next round of the step-by-step upgrading of Wendelstein 7-X has begun. It is to equip the device for greater heating power and longer discharges. Wendelstein 7-X, the world’s largest fusion device of the stellarator type, is to investigate the suitability of this configuration for use in a power plant.

During the course of the step-by-step upgrading of Wendelstein 7-X, the plasma vessel was fitted with inner cladding since September of last year.

Im Focus: New process discovered: Mere sunlight can be used to eradicate pollutants in water

Advances in environmental technology: You don’t need complex filters and laser systems to destroy persistent pollutants in water. Chemists at Martin Luther University Halle-Wittenberg (MLU) have developed a new process that works using mere sunlight. The process is so simple that it can even be conducted outdoors under the most basic conditions. The chemists present their research in the journal “Chemistry - a European Journal”.

The chemists at MLU rely on electrons moving freely in water, so-called hydrated electrons, to degrade dissolved pollutants.

Im Focus: Ultracold quantum mix

The experimental investigation of ultracold quantum matter makes it possible to study quantum mechanical phenomena that are otherwise hardly accessible. A team led by the Innsbruck physicist Francesca Ferlaino has now succeeded for the first time in mixing quantum gases of the strongly magnetic elements Erbium and Dysprosium and creating a dipolar quantum mixture.

Only a few years ago it seemed unfeasible to extend the techniques of atom manipulation and deep cooling in the ultracold regime to many-valence-electron...

Im Focus: First diode for magnetic fields

Innsbruck quantum physicists have constructed a diode for magnetic fields and then tested it in the laboratory. The device, developed by the research groups led by the theorist Oriol Romero-Isart and the experimental physicist Gerhard Kirchmair, could open up a number of new applications.

Electric diodes are essential electronic components that conduct electricity in one direction but prevent conduction in the opposite one. They are found at the...