Instead of completely exchanging expensive components after wear and tear, these can be repaired using deposition welding. Up to now, a gas metal arc welding (GMAW) process has usually been used for deposition welding, with an average feed rate of five kilos per hour.
Since the dilution level is around 30 percent, several layers must be deposited, one on the other, until the protective covering is pure enough. Scientists at the Laser Zentrum Hannover e.V. (LZH) have now, as part of the project HoDopp, developed a laser-supported, light arc process, which achieves this in a single layer.
In the conventional process, the light arc burns between the wire electrode and the workpiece, and fuses both. For large area and multi-layer coatings, the process can take up to 24 hours per square meter. On the other hand, in the process used by the LZH, a light arc burns between two wires and melts them simultaneously.
The deposition rate can thus be increased to around 7.5 kg per hour. The laser beam, which is used in addition to this, assures layer adherence, and improves the form of the seam.
Low thermal stress on the components
Due to the support by the laser beam, the layer is deposited with a low penetration depth, and the dilution rate is thus under five percent. A further advantage of the process is low heat input. Component deformation is notably lower than with deposition welding using conventional GMAW, and the deposition rate can be increased by around 50%.
Since one layer replaces two or three conventionally deposited layers, time and material can be saved for inhomogeneous materials, by half to two-thirds. Thus, productivity and simultaneously the quality of the welding process can be drastically increased.
The project HoDopp: “High-power laser cladding using the twin-wire technique without light-arc transmission and with laser-assisted weld-penetration control” was financed by the Federal Ministry of Education and Research (BMBF). The project was completed at the end of 2014.
The LZH is presenting the process setup and finished components at the Hannover Messe 2015, at the joint stand of the State of Lower Saxony, hall 2, stand A08.
http://www.lzh.de/en/publications/pressreleases/2015/hodopp-high-power-depositio... - website of the press release with video
Lena Bennefeld | Laser Zentrum Hannover e.V.
Dresdner scientists print tomorrow’s world
08.02.2017 | Fraunhofer-Institut für Werkstoff- und Strahltechnik IWS
New technology for mass-production of complex molded composite components
23.01.2017 | Evonik Industries AG
In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport
Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...
The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.
The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...
Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...
Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".
Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...
13.02.2017 | Event News
10.02.2017 | Event News
09.02.2017 | Event News
24.02.2017 | Life Sciences
24.02.2017 | Life Sciences
24.02.2017 | Trade Fair News