Filtern
Erscheinungsjahr
Dokumenttyp
- Zeitschriftenartikel (114) (entfernen)
Sprache
- Englisch (95)
- Deutsch (12)
- Russisch (5)
- Italienisch (1)
- Mehrsprachig (1)
Schlagworte
- Laser beam welding (34)
- Laser welding (15)
- Solidification cracking (10)
- Hybrid laser-arc welding (8)
- Laserstrahlschweißen (8)
- Microstructure (8)
- Electromagnetic weld pool control (6)
- Electromagnetic weld pool support (6)
- Hartmann effect (6)
- Lorentz force (6)
- Natural convection (6)
- Thick-walled steel (6)
- Hybrid laser arc welding (5)
- Laser hybrid welding (5)
- Laser metal deposition (5)
- Mechanical properties (5)
- Austenitic stainless steels (4)
- Critical strain (4)
- High power laser beam welding (4)
- Marangoni flow (4)
- 9%Ni steel (3)
- Additive manufacturing (3)
- Aluminium (3)
- Corrosion (3)
- Full penetration (3)
- Hardness (3)
- Marangoni stresses (3)
- Mechanical mismatching (3)
- Partial penetration (3)
- Pipeline (3)
- Post-weld heat treatment (3)
- Stress reduction (3)
- Weld defects (3)
- Weldability (3)
- CO2 lasers (2)
- Circumferential weld (2)
- Design of experiments (2)
- Duplex (2)
- Duplex AISI 2205 (2)
- Duplex stainless steels (2)
- Electromagnetically controlled laser beam welding (2)
- Electron beam welding (2)
- Elektronenstrahlschweißen (2)
- End crater (2)
- Fiber laser (2)
- Fibre-optic lasers (2)
- Fusion zone size (2)
- Gap bridgeability (2)
- Gas shielded arc welding (2)
- Heat treatment (2)
- High energy beam welding (2)
- High power (2)
- High strength steel (2)
- High-pressure pipelines (2)
- Hot cracking (2)
- Hot cracking test (2)
- Hybrid welding (2)
- Keyhole (2)
- Laser beam weliding (2)
- Laser keyhole welding (2)
- Laser scanner optics (2)
- Laser-hybrid welding (2)
- Laserhybridschweißen (2)
- Local critical strain (2)
- Longitudinal weld (2)
- Manganese (2)
- Marangoni effect (2)
- Matching ferritic welding electrode (2)
- Modified spray arc (2)
- Molten pool (2)
- Nickel (2)
- Numerical simulation (2)
- Optical flow (2)
- Orbital welding (2)
- Partial penetration welding (2)
- Pipe manufacturing (2)
- Porosity prevention (2)
- Preheating (2)
- Residual stresses (2)
- Rissbildung (2)
- Shielding gases (2)
- Simulation and calculation (2)
- Simulation und Berechnung (2)
- Single pass welding (2)
- Spannungen (2)
- Stainless steels (2)
- Stresses (2)
- Thermal cycles (2)
- Vapor plume (2)
- Weld pool shape (2)
- Werkstofffragen (2)
- Wärmebehandlung (2)
- YAG lasers (2)
- laser welding (2)
- 9% Ni Steel (1)
- AC magnetic field (1)
- Additive Fertigung (1)
- Aluminium alloys (1)
- Arc welding (1)
- Artificial Intelligence (1)
- As-shielded arc welding (1)
- Austenitic (1)
- Austenitic welding electrode (1)
- Beam attenuation (1)
- Beam welding (1)
- Bending test (1)
- Build-up strategy (1)
- Bulge effect (1)
- Bulging (1)
- Bulging effect (1)
- CFD model (1)
- CO2 laser (1)
- CO2- and Nd:YAG laser (1)
- Calculation (1)
- Carbon steels (1)
- Charpy impact toughness (1)
- Clad steels (1)
- Combined processes (1)
- Condensation (1)
- Control magnetic field (1)
- Controlled tensile weldability test (1)
- Convolutional neural network (1)
- Corrosion resistance (1)
- Crack formation (1)
- Cracks (1)
- Crater (1)
- Critical strain rate (1)
- Critical strains (1)
- Cryogenic steel (1)
- Deposition rate (1)
- Diagnostic of the torch (1)
- Drop out of bead (1)
- Duplex stainless steel (1)
- Duplex steels (1)
- Edge quality (1)
- Electromagnetic backing (1)
- Electromagnetic rectification (1)
- Electromagnetic stirring (1)
- Electromagnetic support (1)
- Electromagnetic weld control (1)
- Electromagnetic weld pool support system (1)
- Elektromagnetische Badstütze (1)
- Elektromagnetische Schmelzbadunterstützung (1)
- Element transport (1)
- Equivalent heat source (1)
- Ferromagnetic steel (1)
- Ferromagnetic steels (1)
- Festigkeit (1)
- Fibre lasers (1)
- Filler wire mixing (1)
- Fine-grained Steel (1)
- Finite element analysis (1)
- Finite element method (FEM) (1)
- Finite element simulation (1)
- Flow (1)
- Fresnel reflection (1)
- Full penetration laser welding (1)
- Full penetration welding (1)
- GMA welding (1)
- GTAW (1)
- Gas-shielded arc welding (1)
- Heat flow (1)
- Heat source models (1)
- High brightness (1)
- High power fibre laser (1)
- High-Power Welding (1)
- High-power fibre laser (1)
- High-power laser beam (1)
- High-power laser beam welding (1)
- High-strength low-alloy steel (1)
- Higher manganese content (1)
- Hot crack (1)
- Hybrid Laser Arc Welding (1)
- Hybrid Laser arc Welding (1)
- Hybrid Laser-Arc Welding (1)
- Hydrostatic force compensation (1)
- Imaging (1)
- Impact Absorbed Energy (1)
- Impact absorbed energy (1)
- In situ strain (1)
- Inconel 718 (1)
- Kaltzähe Stähle (1)
- Keyhole mode welding (1)
- Keyhole stability (1)
- Lamé curves approximation (1)
- Laser Beam Welding (1)
- Laser Metal Deposition (1)
- Laser Metal Deposition (LMD) (1)
- Laser Powder Bed Fusion (1)
- Laser beam Welding (1)
- Laser cutting (1)
- Laser metal fusion (1)
- Laser powder cladding (1)
- Laser surfacing (1)
- Laser-Pulver-Auftragschweißen (1)
- Liquid Metal Embrittlement (1)
- Local reduced pressure (1)
- Lokale Effekte (1)
- Lötrissigkeit (1)
- MRO (1)
- Magnetfelder (1)
- Magnetic bath support (1)
- Magnetic field (1)
- Magnetohydrodynamics (1)
- Maritime industry (1)
- Matching ferritic filler metal (1)
- Mathematical models (1)
- Mechanical Properties (1)
- Mechanical-technological properties (1)
- Melt pool dynamics (1)
- Metal mixing (1)
- Microstructure Tensile strength (1)
- Misalignment of edges (1)
- Mobile vacuum (1)
- Modeling of fluid flow (1)
- Modellierung (1)
- Multi-physical modeling (1)
- Multi-physical modelling (1)
- Multirun welding (1)
- Ni-based austenitic filler metal (1)
- Ni-based austenitic welding electrode (1)
- Novel metrology (1)
- Novel optical measurement (1)
- Numerical modeling (1)
- Numerical process simulation (1)
- Numerical simulations (1)
- Optical measurement (1)
- Optical measurment technique (1)
- Oscillating magnetic field (1)
- Particles (1)
- Pipe Welding (1)
- Pipe laying (1)
- Pipe welding (1)
- Pipeline steel of grade X120 (1)
- Plasma cutting (1)
- Plasma-cut samples (1)
- Plume (1)
- Plume heating (1)
- Poren (1)
- Pores (1)
- Position welding (1)
- Post-welding heat treatment (1)
- Process combinations (1)
- Process simulation (1)
- Process stability (1)
- Prozesskombinationen (1)
- Pufferschichten (1)
- Reference lists (1)
- Repair welding (1)
- Residual stress (1)
- Rissanfälligkeit (1)
- SMAW (1)
- Schutzgasschweißen (1)
- Schweißeignung (1)
- Schweißnahtfehler (1)
- Schweißnahtimperfektionen (1)
- Schweißunregelmäßigkeiten (1)
- Secondary heat source (1)
- Selective Laser Melting (1)
- Shielding atmosphere (1)
- Ship building (1)
- Shipbuilding steel (1)
- Simulating (1)
- Single-pass welding (1)
- Software (1)
- Solidification (1)
- Stainless Steel (1)
- Stainless austenitic and duplex steels (1)
- Stainless steel (1)
- Steels (1)
- Strain fields prediction (1)
- Strain measurement (1)
- Strain rate (1)
- Strain rates (1)
- Submerged arc welding (1)
- Surface roughness (1)
- Temperature distribution (1)
- Tensile Strength (1)
- Tensile strength (1)
- Thermal analysis (1)
- Thermo-fluid flow (1)
- Thick materials (1)
- Thick plate (1)
- Thick plate welding (1)
- Thick plates (1)
- Thick walled parts (1)
- Thick-Walled Steel (1)
- Thick-plate welding (1)
- Thick-walled Structures (1)
- Ti3Al2.5V (1)
- Tick plates (1)
- Titanium alloy (1)
- Toughness (1)
- Tube welding (1)
- Turbine blade (1)
- Two-run welding technique (1)
- Unalloyed steels (1)
- V-notch impact toughness (1)
- Vakuum (1)
- Vapor recondensation (1)
- Weld imperfections (1)
- Weld metal (1)
- Weld microstructure (1)
- Weld pool (1)
- Weld pool stabilization (1)
- Weld pool support (1)
- Weld root (1)
- Welding simulation (1)
- Welding thermal cycle (1)
- Werkstoffranking (1)
- Widerstandspressschweißen (1)
- Widerstandspunktschweißen (1)
- Windkraftanlagen (1)
- cryogenic steel (1)
- hardness (1)
- hochfeste Stähle (1)
- local effects (1)
- microstructure (1)
- tensile strength (1)
- vacuum (1)
- Ökonomische und ökologische Vorteile (1)
Organisationseinheit der BAM
During laser beam welding of aluminum alloys an electromagnetic field may favour pore outgassing through the top oxide layer. High frequencies cause a small penetration depth and thus exert a stabilizing effect on the weld surface. The point at which the laser beam between the two magnetic poles hits the workpiece surface is crucial to the influence of the magnetic field on the weld surface roughness. Using analyzed parameters for different laser points of application cause a change in weld surface roughness could be observed. The weld surface roughness could be reduced by 50%. The outgassing effect in terms of a reduction of pores could be observed for all parameter sets investigated.
Longitudinal residual stresses in beam welds ranging at the value of the local yield strength can diminish the lifespan of components. To extend the service life of welds special methods of welding residual stress reduction were developed earlier which are however not effective for beam welds in complex component geometries. Application of beam welding sources for postwelding heat treatment of components has become a flexible tool for reducing longitudinal stresses in beam welds. Such heat treatment in a specific transversal distance to the weld by a defocused beam results in huge stress reductions depending on the used process parameters. Experimental results for ferritic and austenitic steels reveal weld stress reductions to up to compressive stresses. For different materials and diverse material thicknesses special process parameter regions have to be used in this procedure. At a transmission component this procedure shows a stress reduction by >300 MPa.
Schweißzugeigenspannungen in Strahlschweißnähten auf Höhe der lokalen Werkstoffstreckgrenze können die Bauteileigenschaften sowie deren Lebensdauer beeinflussen. Die Nutzung der Schweißquelle für eine nachträgliche Behandlung der geschweißten Bauteile bietet eine kostengünstige und flexible Methode zur Reduzierung dieser Spannungen. Dabei wird durch einen oszillierenden defokussierten Elektronen- bzw. Laserstrahl der Werkstoff beidseitig der Schweißnaht auf mehrere hundert Grad Celsius erwärmt, um dort zusätzliche Zugspannungsbereiche hervorzurufen. Die so erzeugten Längszugspannungszonen führen zu einer mechanischen Entlastung der Schweißnaht. Experimentelle Messungen zeigen, dass die Längseigenspannungen in der Schweißnaht mit diesem Verfahren um bis zu 70% reduziert werden können. Hierbei wurde neben der experimentellen Untersuchung dieses Verfahrens an Linearnähten an 5 mm dicken Blechen des Werkstoffs S355J2+N auch eine umfassende Analyse der Einflüsse der Verfahrensparameter auf die Spannungsreduktion mittels FEMSimulation durchgeführt. Anhand der Ergebnisse wird der Entlastungsmechanismus diskutiert. ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Residual tensile welding stresses in beam welds at the level of the local yield strength of the material may influence the properties of components as well as their service lives. The utilisation of the welding source for the subsequent treatment of the welded components offers a cost-favourable and flexible method of reducing these stresses. In this respect, an oscillating defocused electron or laser beam serves to heat the material on both sides of the weld up to several hundred degrees Celsius in order to induce additional tensile stress regions there. The longitudinal tensile stress zones produced in this way lead to the mechanical relief of the weld. Experimental measurements show that the longitudinal residual stresses in the weld can be reduced by up to 70% with this process. In this case, not only was the experimental investigation into this process conducted on linear welds on 5 mm thick sheets made of the S355J2+N material but a comprehensive analysis of the influences of the process parameters on the stress reduction was also made by means of FEM simulation. The relief mechanism is discussed on the basis of the results.
Schweißzugeigenspannungen in Strahlschweißnähten auf Höhe der lokalen Werkstoffstreckgrenze können die Bauteileigenschaften sowie deren Lebensdauer negativ beeinflussen. Die Nutzung der Schweißquelle für eine nachträgliche Behandlung der geschweißten Bauteile bietet eine kostengünstige und flexible Methode zur Reduzierung dieser Spannungen. Dabei wird durch einen oszillierenden defokussierten Elektronen- bzw. Laserstrahl, der Werkstoff beidseitig der Schweißnaht auf mehrere hundert Grad Celsius erwärmt, um dort zusätzliche Zugspannungsbereiche hervorzurufen. Die so erzeugten Längszugspannungszonen führen zu einer mechanischen Entlastung der Schweißnaht. Experimentelle Messungen der Längseigenspannungen an linearen Elektronen- und Laserstrahlschweißnähten im ersten Teil des Beitrags zeigten, dass die Spannungen mit diesem Verfahren um bis zu 70% reduziert werden können. In weiteren experimentellen Untersuchungen wird dieses Verfahren für kompliziertere Schweißnahtgeometrien getestet. An axialen sowie radialen Rundnähten an ferritischen Werkstoffen konnten ebenfalls hohe Spannungsreduktionen von über 50% erzielt werden. Zudem wurde dieses Verfahren mit einer für das Schweißen üblichen Laserstrahlschweißoptik ohne Scan-Funktion geprüft. Hierbei zeigte das Wärmebehandeln in zwei Arbeitsschritten noch größere Spannungsreduktionen im Vergleich zur Anwendung einer Laserstrahlscanneroptik zur quasisimultanen Wärmebehandlung auf beiden Seiten der Schweißnaht. -------------------------------------------------------------------------------------------------------------------------------------------
Residual tensile welding stresses in beam welds at the level of the local yield strength of the material may influence the properties of components as well as their service lives. The utilisation of the welding source for the subsequent treatment of the welded components offers a cost-favourable and flexible method of reducing these stresses. In this respect, an oscillating defocused electron or laser beam serves to heat the material on both sides of the weld up to several hundred degrees Celsius in order to induce additional tensile stress regions there. The longitudinal tensile stress zones produced in this way lead to the mechanical relief of the weld. Experimental measurements of the longitudinal residual stresses on linear electron and laser beam welds in the first part of the article showed that the stresses can be reduced by up to 70% with this process. In further experimental investigations, this process is tested for more complicated weld geometries. It was also possible to achieve great reductions in the stresses (over 50%) on both axial and radial circular welds on ferritic materials. Moreover, this process was tested with laser beam welding optics which are customary for welding and do not perform a scanning function. In this respect, the heat treatment in two work steps showed even greater reductions in the stresses in comparison with the application of laser beam scanner optics for quasi-simultaneous heat treatment on both sides of the weld.
IIW-2326
Austenitic and austenitic-ferritic CrMnNi-stainless steels are suitable materials in the transport and automotive industry due to their high corrosion resistance and high strength that allows weight and cost savings. This study focuses on the laser weldability of a commercial lean duplex and an austenitic high manganese stainless steel. The impact of different laser sources, i.e. a 5 kW CO2- and a 4 kW Nd:YAG-laser, and of the main process parameters on the resulting weld quality will be investigated. One important aspect will concern the appearance of weld defects such as pores and hot cracks. The factors causing such internal imperfections will be analysed in order to find effective methods for preventing them. Weld microstructure and the associated corrosion and mechanical properties will be assessed with different techniques and adequate process parameters for high quality welds will be determined. The advantages and limitations of the applied welding processes will be evaluated for future applications.
A three-dimensional laminar steady-state numerical model was developed to investigate the influence of an alternating current (ac) magnetic field during high-power full-penetration laser welding on the weld pool dynamics and weld cross section of a 20 mm thick aluminium plate in flat position. Three-dimensional heat transfer, fluid dynamics including phase transition and electromagnetic field partial differential equations were solved iteratively with the commercial finite element software COMSOL Multiphysics using temperature-dependent material properties up to evaporation temperature. Thermocapillary convection at the weld pool surfaces, natural convection and latent heat of solid–liquid phase transition were taken into account in this model. Solidification was modelled by the Carman–Kozeny equation for porous media morphology. The ac magnet was mounted on the root side of the weld specimen. The magnetic field was aligned perpendicular to the welding direction. The flow pattern in the melt and thus also the temperature distribution were significantly changed by the application of oscillating magnetic fields. It was shown that the application of an ac magnetic field to laser beam welding allows for a prevention of the gravity drop-out. The simulation results are in good qualitative agreement with the experimental observations.
The results of an in-situ plume-laser interaction measurement during welding of mild steel with a 5 kW ytterbium fiber laser are reported. A measurement of the attenuation of probe laser beam passing through the plume has allowed to estimate the plume characteristics like the size of the extinction area and the spatial distribution of the extinction coefficient. The power loss of the fiber laser radiation propagating through the whole plume length was calculated. Together with a measured temporal characteristics of extinction the result indicates a significant decreasing of the laser radiation stability, which can lead to the formation of the macroscopic welding defects.
The residual stresses in narrow electron or laser beam welds with high stress gradients are decreased without any contact surfaces or additional equipment by applying the welding beam after welding in a defocused mode for heating the material regions in a certain distance from the weld on both sides. In case of electron beam application, the beam is positioned and focused by the electromagnetic coil with high frequency. In case of laser beam application a laser scanner optics enables fast positioning by an optomechanic beam deflection, while defocusing of the laser beam is obtained by increasing the distance between scanner optics and workpiece. Dependent on the component geometry and on the beam power different process parameters are used. The adjustable process parameters are the radius and the power of the defocused beam and the transversal and longitudinal distances between the welding and the defocused beam. The mechanism and the influence of the process parameters are investigated by FEM-simulation and a number of experiments on a ferritic steel S355J2+N with 5 mm thickness. FEM-simulation is used to reduce the matrix of process parameters for the experiments. The best experimental result shows a stress reduction of about 70%.