A5018127443- Welding Techniques and Residual Stresses
- Advanced Welding Techniques Analysis
- Laser and Thermal Forming Techniques
- Laser Material Processing Techniques
- Additive Manufacturing Materials and Processes
- Hydrogen embrittlement and corrosion behaviors in metals
- Metal Forming Simulation Techniques
- Microstructure and Mechanical Properties of Steels
- Non-Destructive Testing Techniques
- Corrosion Behavior and Inhibition
- Aluminum Alloy Microstructure Properties
- Advanced Surface Polishing Techniques
- Ultrasonics and Acoustic Wave Propagation
- Metal Alloys Wear and Properties
- High-Temperature Coating Behaviors
- High Entropy Alloys Studies
- Advanced Machining and Optimization Techniques
- Manufacturing Process and Optimization
- Metallurgy and Material Forming
- Industrial Vision Systems and Defect Detection
- Engineering Technology and Methodologies
- Intermetallics and Advanced Alloy Properties
- Material Properties and Applications
- Advanced machining processes and optimization
- Surface Roughness and Optical Measurements
Laser Zentrum Hannover
2016-2025
Dissimilar joints of steel and aluminum are in great demand shipbuilding applications, such as connecting hulls to superstructures. For this welding application, an explosive-welded adapter is used, whose manufacturing complex cost-intensive. While searching for alternative processes, laser beam has emerged due its specific advantages. Compared other fusion joining enables a better control the weld metal mixing ratio and, thus, microstructure. To achieve constant homogeneous microstructure...
Abstract Laser beam welding is a commonly used technology for joining similar and dissimilar materials. In order to improve the mechanical properties of weld, introduction ultrasonic vibration into weld zone has been proposed [5]. The system consists an electronic control, power supply, piezoelectric converter sonotrode, which introduces zone. Its proper design great importance process performance. Furthermore, effects ultrasound in melt pool need be understood evaluate optimize parameters....
Laser beam welding is used in many areas of industry and research. There are strategies approaches to further improve the weld seam properties laser welding. Metallography often needed evaluate welded seams. Typically, images examined evaluated by experts. The evaluation process qualitatively provides welds. Particularly times when artificial intelligence being more processes, quantization that could previously only be determined gaining importance. In this contribution, we propose use deep...
Recent developments in laser beam sources expand the possibilities of welding similar and dissimilar copper joints. New methods shaping adjustable intensity profiles using two layer fibers create a center ring spot, which is newest state art fiber sources. In this study, influences on weldability steel lap joints with top side will be discussed. The results show that former problems spattering poor coupling can avoided through new technologies adjusted parameter settings. investigations...
Nowadays, there is a strong and growing ambition to switch from combustion technology battery-electric drives, energy storage spotlighted. Laser beam welding an appropriate favorable in battery production. Due the high speed, local heat input, contact freeness efficient, automatable processes can be established. Materials used batteries for electrodes that have connected are commonly copper aluminum. Specifically, highly reflective widely infrared laser wavelengths. Furthermore, thickness...
Lightweight construction plays an important role in meeting the increasing demands of automotive industry regarding weight reduction. In this work, two approaches have been chosen: reduction based on material and design. Steel aluminum are used for first approach, hydroforming is method design optimization by shaping. Mixed seams steel generated using laser soldering brazing to make steel-aluminum tailored hybrid tubes hydroforming. The seam has provide sufficient formability strength. main...
Abstract The Collaborative Research Center 1153 is investigating an innovative process chain for the production of hybrid components. workpieces are first joined and then formed by cross-wedge rolling. Pinion shafts were manufactured to investigate behavior joining zone under increased complexity forming process. For this purpose, six types produced three processes into pinion shafts. reference provides a shaft with smooth bearing seat. It was found that did not present any challenges...
Laser beam brazing is an established manufacturing process due to its low heat input and esthetically appealing seams. However, of materials with high oxygen affinity, such as aluminum alloys, requires the removal surface oxides prior process, commonly through application chemical fluxes that may be harmful environment health. The approach presented here dispenses use involves oxide layer by means ns-pulsed laser radiation within atmosphere adequate extreme vacuum (XHV) in regard content. By...
For joining of thick steel plates, commonly arc welding and partially laser-arc hybrid are used. Both techniques offer individual disadvantages besides their advantages. Arc processes typically characterized by low speeds, high heat inputs, distortions, filler material consumptions. Laser-arc limited to weldable thicknesses regarding weld imperfections as well the ability bridge gaps. Therefore, investigations presented about high-power diode laser beam with plate t between 15 30 mm using...
There are many reasons for influencing the laser beam induced weld pool. The manipulation of dynamics, solidification, resulting grain size, and in end, as a result aforementioned influencing, mechanical characteristics is aim different attempts to gain an impact on melt. Aluminum alloys tend porosity formation because solubility hydrogen solid liquid states. For reliable welds, has be limited. An ultrasound excitation one possibility allow fast degassing, especially considered round bars,...
Welding by laser beam is a method for creating deep and narrow welds with low influence on the surrounding material. Nevertheless, microstructure mechanical properties change, highly alloyed materials are prone to segregation. A new promising approach minimizing segregation its effects like hot cracks introducing ultrasonic excitation into specimen. The following investigations about of different amplitudes (2/4/6 µm) positions weld pool in resonant vibration distribution (antinode,...
Aluminium alloys, like AlMgSi1 and AlMg3, cannot be joined in industrial processes by laser beam brazing without the use of fluxes due to their resistant oxide layer. The aim this study is dispense with flux. For investigations, an oxygen-free atmosphere was created using highly reactive gas monosilane thus achieving O2 partial pressures 10−18 mbar. After removal oxides a source 1064 nm wavelength, pulse energies max. 0.3 µJ durations 45 ns, reoxidation prevented atmosphere, so that carried...
There are many different steel grades available for various purposes and applications. For semi-finished workpieces with different, specific local requirements regard to mechanical or chemical properties, a strong joint between the is necessary. Additionally, subject forming require sufficient plasticity in area of joint. In thermal welding metals, new alloy always appears weld itself. This means, example, that due grain growth interfaces graded transitions, induced negative restrictive...
An ever-increasing demand for more effective products with lower weight, compact design and extended functionality has led to the use of material combinations locally adapted properties instead mono-materials. The Collaborative Research Centre (CRC) 1153 "Tailored Forming" at LUH addresses this topic aim develop hybrid bulk-metal components on basis a new, tailored production process using joined semi-finished products. In contrast existing manufacturing processes where joining takes place...
The risk of weld defects increases when laser beam welding round bars is performed in a rotational process. reason heat accumulation, which changes process conditions. analysis pool shape and the course seam essential for being able to evaluate overall quality set up control measures. This study focuses on with partial welds various speeds. experiments are carried out 1.7035 30 mm diameter. For welds, power 6 kW speed 1 m/min used paths 1/4, 1/2, 3/4 circumference. Welding speeds conducted...
Fusion joining of stainless steel to copper without a filler material for pipe processing proves itself be challenging due the very different properties partners and heterogeneous characteristics in weld metal mixing ratios. One most common defects this combination is solidification cracking liquid accumulation between grain boundaries, which cannot withstand tensile tensions while cooling down. Consequently, these cracks can reduce mechanical properties, lead leakages or cause faster...
Adapted laser beam and intensity shapes realized by fiber design offer many opportunities, especially for welding. An adjustable ring mode source was used the investigations presented. Continuous pulsed are possible, so combinations temporal overlays of inner outer power feasible with a maximum 6 kW. This work shows several metallic materials combinations. For welding similar lap joints made aluminum-silicon coated hot forming manganese-boron steel influence different profiles is analyzed...
With increasing demand for pure copper welds in the production of electronic connections, various approaches were pursued to reduce challenging spatter and melt ejection susceptibility laser beam welding processes materials. One is use adjustable intensity profiles infrared sources with a combination core ring beam, which enables wider more stable keyhole deep penetration makes reduction spattering ejections possible. In order research influence different power distributions powers up 4000 W...