Wissenschaftliche Artikel der BAM
Filtern
Dokumenttyp
Sprache
- Englisch (151)
Referierte Publikation
- ja (151) (entfernen)
Schlagworte
- Additive manufacturing (20)
- Laser beam welding (18)
- Welding (13)
- Mechanical properties (9)
- Microstructure (9)
- Residual stresses (9)
- Hydrogen (8)
- Residual stress (8)
- Additive Manufacturing (7)
- Laser powder bed fusion (7)
- Creep-resistant steel (6)
- Solidification cracking (6)
- Ultrasonic-assisted milling (6)
- Process monitoring (5)
- Resistance spot welding (5)
- Thermography (5)
- AISI 316L (4)
- Diffusible hydrogen (4)
- Fatigue (4)
- Friction (4)
- Heat accumulation (4)
- High-strength steel (4)
- Laser Powder Bed Fusion (4)
- Neutron diffraction (4)
- Numerical modeling (4)
- Selective laser melting (SLM) (4)
- Stress relief cracking (4)
- Surface integrity (4)
- Wear (4)
- AGIL (3)
- Alloy 36 (3)
- Hybrid laser arc welding (3)
- In situ monitoring (3)
- Inconel 718 (3)
- Infrared thermography (3)
- Laser metal deposition (3)
- Laser powder bed fusion (L-PBF) (3)
- Polymers (3)
- Post weld heat treatment (3)
- Steel (3)
- Submerged arc welding (3)
- TIG welding (3)
- Ti-6Al-4V (3)
- Varestraint test (3)
- AISI 304L (2)
- Additive manufacturing (AM) (2)
- Alloy modification (2)
- Artificial neural network (2)
- Atomic force microscopy (2)
- Computed Tomography (2)
- Computed tomography (2)
- Crack (2)
- Cracking (2)
- Crystallographic texture (2)
- Deep penetration (2)
- Deuterium (2)
- EBSD (2)
- Electron backscattered diffraction (2)
- Finite element simulation (2)
- Fracture (2)
- Full penetration (2)
- GMA welding (2)
- Gas metal arc welding (2)
- Grain refinement (2)
- Hardmetal (2)
- Hardness (2)
- Heat control (2)
- High entropy alloy (2)
- High strength steels (2)
- High-power laser beam welding (2)
- High-strength structural steel (2)
- Hybrid laser-arc welding (2)
- Hydrogen assisted cracking (2)
- Hydrogen embrittlement (2)
- Hydrogen-assisted cracking (2)
- Implant test (2)
- LPBF (2)
- Laser beam melting (LBM) (2)
- Laser energy distribution (2)
- Liquid metal embrittlement (2)
- Mechanical Engineering (2)
- Mechanics of Materials (2)
- Metals and Alloys (2)
- Microstructure characterization (2)
- Numerical simulation (2)
- Offshore (2)
- Plasma-transferred arc welding (2)
- Porosity (2)
- Post-weld heat treatment (2)
- Quality assurance (2)
- Ray tracing (2)
- Refill friction stir spot welding (2)
- Representative specimens (2)
- Residual Stress (2)
- Residual stress analysis (2)
- Selective Laser Melting (2)
- Selective Laser Melting (SLM) (2)
- Simulation (2)
- Software (2)
- Texture (2)
- Thermal history (2)
- ToF-SIMS (2)
- WAAM (2)
- Wire arc additive manufacturing (2)
- X-ray diffraction (2)
- 2101 duplex stainless steel (1)
- 316L (1)
- 3D Scanning (1)
- 3D printing (1)
- 9%Ni steel (1)
- AC magnetic field (1)
- AFM (1)
- AHSS (1)
- AM feature integration (1)
- ASTM E647 (1)
- Accoustic emission (1)
- Additive Manufacturing (AM) (1)
- Advanced high strength steels (1)
- Advanced high-strength steel (1)
- Aging (1)
- AlMg0.7SiTiB filler wire (1)
- Alkyd resin-based coating (1)
- Aluminum alloys (1)
- Aluminum bronze (1)
- Analytical calculation (1)
- Artificial Intelligence (1)
- Artificial intelligence (1)
- As-built LPBF IN718 alloy (1)
- Austenite-to-martensite transformation (1)
- Automated manufacturing (1)
- Automotive (1)
- Bayesian technique (1)
- Bending test (1)
- Binders (1)
- Bismuth titanates (1)
- Bragg-edge imaging (1)
- Bulge effect (1)
- Bulge formation (1)
- Bulging effects (1)
- CFD model (1)
- Carbide (1)
- Carbon (1)
- Carbon dioxide footprint (1)
- Carbon steel (1)
- Catalysis (1)
- Cellular substructure (1)
- Cermet (1)
- Characterization (1)
- Characterization of corrosion layers (1)
- Charakterisierung (1)
- Chemical composition (1)
- Chunky graphite (1)
- Clustering (1)
- Co-Cr-alloy (1)
- Cobalt-chromium alloy (1)
- Cold cracking (1)
- Cold cracking safety (1)
- Columnar crystal growth (1)
- Component test (1)
- Component-like test (1)
- Composites (1)
- Computed tomography (CT) (1)
- Computer vision (1)
- Condensed Matter Physics (1)
- Contact resonance (1)
- Convolutional neural network (1)
- Convolutional neural networks (CNN) (1)
- Core-shell structures (1)
- Creep (1)
- Creep behavior (1)
- Creep-resisting materials (1)
- Cryogenic temperature (1)
- Crystal branch development (1)
- Crystal plasticity (1)
- Cutting forces (1)
- Cutting tool (1)
- Cyclic R-curve (1)
- Cyclic loading (1)
- DED (1)
- DED-EB (1)
- DED-arc (1)
- Damage prediction (1)
- Data evaluation methods (1)
- Data fusion (1)
- Data preparation (1)
- Data-driven quality assurance (1)
- Debye–Waller factor (1)
- Deep learning (1)
- Deep penetration laser beam welding (1)
- Defect detection (1)
- Defects (1)
- Dental materials (1)
- Dichtungen (1)
- Diffraction (1)
- Diffraction-elastic constants (1)
- Diffusion (1)
- Diffusion/diffusivity (1)
- Digital image correlation (1)
- Digitalization (1)
- Direct laser deposition (1)
- Dislocation density (1)
- Dispersive XAS (1)
- Displacement (1)
- Dissimilar joints (1)
- Dissimilar materials (1)
- Dissimilar metal weld (1)
- Distortion (1)
- Distortion upon baseplate removal (1)
- Ditigtal image correlation (1)
- Dual phase steel (1)
- Duplex AISI 2205 (1)
- Duplex steels (1)
- Dwell-time (1)
- EBAM (1)
- Edge quality (1)
- Effect of scanning strategies (1)
- Elastic modulus (1)
- Elastomers (1)
- Electrochemical permeation (1)
- Electromagnetic field (1)
- Electromagnetic forces (1)
- Electromagnetic stirring (1)
- Electron backscatter diffraction (1)
- Electron beam welding (1)
- Electron microscopy (1)
- Emisssivity (1)
- Energy Engineering and Power Technology (1)
- Environmental impact categories (1)
- Experimental determination (1)
- FAIR data (1)
- FAT class (1)
- FEM (1)
- Fatigue Strength (1)
- Fatigue crack propagation threshold (1)
- Fatigue damage (1)
- Fatigue limit (1)
- Fatigue tests (1)
- Femtosecond laser (1)
- Femtosecond laser processing (1)
- Ferritic spheroidal graphite cast iron (1)
- Ferroelectricity/ferroelectric materials (1)
- Filler wire mixing (1)
- Finish milling (1)
- Finite element (FE) (1)
- Finite element analysis (1)
- Finite element method (1)
- Finite element method (FEM) (1)
- Flange width (1)
- Flaw detection (1)
- Flüssigmetallinduzierte Rissbildung (1)
- Force-distance curves (1)
- Formation (1)
- Fractography (1)
- Fracture Mechanics (1)
- Frequency domain (1)
- Friction stir welding (1)
- Fuel Technology (1)
- Galvanized steel (1)
- Gap bridgeability (1)
- Gas tungsten arc welding (GTAW) (1)
- General analytical solutions (1)
- HAZ-softening (1)
- HSLA steel (1)
- Hardly separable problem (1)
- Hastelloy X (1)
- Heat source models (1)
- Heat treatment (1)
- Heat-affected zone (1)
- High process speeds (1)
- High-entropy alloy (1)
- High-entropy alloys (1)
- High-pressure hydrogen environment (1)
- High-strength filler metals (1)
- High-strength steel filler metal (1)
- High-strength steels (1)
- Hochfester Stahl (1)
- Hollow Specimen Technique (1)
- Hot cracking (1)
- Hot tensile test (1)
- Hybrid repair (1)
- Hydrogen Embrittlement (1)
- Hydrogen Transfer Film (1)
- Hydrogen diffusion (1)
- Hydrogen measurement (1)
- IBESS (1)
- IBESS Approach (1)
- IN 718 (1)
- IN725 (1)
- ISO 12108 (1)
- Image processing (1)
- Image registration (1)
- Implants (1)
- In situ (1)
- In-situ process monitoring (1)
- Inconel 625 (1)
- Instumented indentation test (1)
- Integrated alignment features (1)
- Inter layer time (1)
- Inter-layer time (1)
- Joining dissimilar materials (1)
- Joining technology (1)
- Kernel average misorientation (1)
- Keyhole collapse (1)
- Keyhole dynamics (1)
- L-PBF (1)
- L-PBF IN718 material (1)
- LIBS (1)
- LMD (1)
- LTT filler metal (1)
- LTT weld filler materials (1)
- Lack-of-fusion (1)
- Lamé curves (1)
- Large-scale test (1)
- Laser Powder Bed Fusion (L-PBF) (1)
- Laser Powder Bed Fusion (LPBF) (1)
- Laser Powder Bed Fusion (PBF-LB/M, L-PBF) (1)
- Laser beam melting (1)
- Laser cutting (1)
- Laser energy absorption (1)
- Laser powder-based directed energy deposition (1)
- Laser welding (1)
- Laser-based additive manufacturing (1)
- Laser-induced oxide layer (1)
- Laser-induced periodic surface strctures (LIPSS) (1)
- Lead-free ceramics (1)
- Life cycle assessment (1)
- Lifetime (1)
- Liquid Metal Embrittlement (1)
- Liquid phase sintering (1)
- Local Weld Geometry (1)
- Lorentz force (1)
- Lorentz forces (1)
- Low transformation temperature (LTT) steel (1)
- Low-cycle fatigue (1)
- Lubricants (1)
- L‐PBF (1)
- MVT (1)
- MWIR (1)
- Machine learning (1)
- Machine vision (1)
- Machining (1)
- Magnesium Alloy (1)
- Magnesium alloy (1)
- Magnetic field (1)
- Martensite (1)
- Matching ferritic filler metal (1)
- Mechanical anisotropy (1)
- Mechanical mismatching (1)
- Mechanical property (1)
- Medium entropy alloy (1)
- Melt pool dynamics (1)
- Metal (1)
- Metal mixing (1)
- Microalloying influences (1)
- Microbiologically influenced corrosion (1)
- Microcracking (1)
- Microfocus X-ray computer tomography (μCT) (1)
- Mild steels (1)
- Minimum Waiting Time (1)
- Mining head gear (1)
- Model calibration (1)
- Model order reduction (1)
- Modellierung (1)
- Modelling studies (1)
- Modification of structural morphology (1)
- Molten pool (1)
- Multi-materials joining (1)
- Multi-physical modelling (1)
- Multi-principal element alloy (1)
- Multi-principal element alloys (1)
- Multiple principal element alloy (1)
- NIR (1)
- Nanotribology (1)
- Natural silver wires (1)
- Near-surface X-ray diffraction (1)
- Neutron Diffraction (1)
- Neutron and X-ray diffraction (1)
- Neutron radiography (1)
- Ni alloy (1)
- Ni-based austenitic filler metal (1)
- Nickel (1)
- Niobium carbide (1)
- Niobium carbide (NbC) (1)
- Notch stress approach (1)
- Numerical investigation (1)
- Numerical process simulation (1)
- Numerical welding simulations (1)
- Offshore steel grade (1)
- Online Process Monitoring (1)
- Online monitoring (1)
- Open science (1)
- Open source (1)
- Optical Tomography (1)
- Optical tomography (1)
- Oscillating magnetic field (1)
- Oscillating vapor plume (1)
- Oxidation (1)
- PBF-LB/M/316L (1)
- Parabolic flight (1)
- Path planning (1)
- Peak stress method (1)
- Peak stress method (PSM) (1)
- Periodic solidification pattern (1)
- Pipe weld preparation (1)
- Plasma cutting (1)
- Plastic deformation (1)
- Polymere (1)
- Polyurethan (1)
- Position detection (1)
- Post Weld Heat Treatment (PWHT) (1)
- Potential drop technique (1)
- Potentiodynamic measurements (1)
- Precipitation hardening aluminum alloys (1)
- Preheating (1)
- Pressure-dependent solubility (1)
- Prevention (1)
- Probabilistic assessment (1)
- Process simulation (1)
- Projekt AGIL - Alterung additiv gefertigter metallischer Materialien und Komponenten (1)
- Proper generalized decomposition (1)
- Properties (1)
- Prostheses (1)
- Quality monitoring (1)
- Ray teacing (1)
- Ray-tracing methods (1)
- Reactor conditions (1)
- Reference data (1)
- Reference standards (1)
- Renewable Energy, Sustainability and the Environment (1)
- Repair welding (1)
- Repair-welding (1)
- Research data management (1)
- Residual Stresses (1)
- Residual stress in AM (1)
- Residual stress state (1)
- Roughness (1)
- S-N curve (1)
- S-Phase (1)
- SEM (1)
- SIMS (1)
- SWIR (1)
- SWIR thermography (1)
- Sample random results (1)
- Scan strategy influence (1)
- Shear modulus (1)
- Ship building (1)
- Shipbuilding steel (1)
- Single asperity (1)
- Sliding wear (1)
- Solidification (1)
- Solubility (1)
- Spark plasma sintering (1)
- Stainless Steel (1)
- Stainless steel (1)
- Stainless steels (1)
- Staircase method (1)
- Steel and aluminium (1)
- Stochastic sample functions (1)
- Strain fields prediction (1)
- Strain-free lattice references (1)
- Strain-free lattice spacing (1)
- Stress Relief Cracking (SRC) (1)
- Stress balance (1)
- Stress balance condition (1)
- Structural stress approach (1)
- Structure analysis (1)
- Sub-oxide (1)
- Surface preparation (1)
- Surface processing (1)
- Synchrotron radiation (1)
- TEKKEN (1)
- Temperature (1)
- Temperature dependence (1)
- Tensile loading (1)
- Tensile properties (1)
- Tensile resistance spot welding experiment (1)
- Tensile strength (1)
- Tensile testing (1)
- Thermal analysis (1)
- Thermodynamic modelling (1)
- Thermodynamic simulation (1)
- Thick materials (1)
- Thick-walled (1)
- Thick-walled steel (1)
- Titanium (1)
- Trapping (1)
- Tribologie (1)
- Tribology (1)
- Tubular X-joints (1)
- Two-dimensional solidification (1)
- Two-run welding technique (1)
- UV-blocker addition (1)
- Upscaling (1)
- Varestraint testing (1)
- Weathering tests (1)
- Weld metal cracking (1)
- Weld pool (1)
- Weld pool dynamics (1)
- Weld pool shape (1)
- Weldability (1)
- Welded Joints (1)
- Welded joint (1)
- Welded joints (1)
- Welding simulation (1)
- Weldx (1)
- Widerstandspunktschweißen (1)
- Wind energy (1)
- Wire electron beam additive manufacturing (1)
- Wire feed laser beam welding (1)
- Wire-based additive manufacturing (1)
- X-ray Diffraction (1)
- X-ray and Neutron Diffraction (1)
- X-ray and neutron diffraction (1)
- X-ray computed tomography (XCT) (1)
- X-ray refraction (1)
- Young's modulus (1)
- Zink (1)
- i-TRIBOMAT (1)
- infrared Thermography (1)
- µ-gravity (1)
- µCT (1)
- μCT-analysis (1)
Organisationseinheit der BAM
- 9 Komponentensicherheit (151) (entfernen)
Paper des Monats
- ja (9)
One of the main factors affecting the use of lasers in the industry for welding thick structures is the process accompanying solidification cracks. These cracks mostly occurring along the welding direction in the welding center, and strongly affect the safety of the welded components. In the present study, to obtain a better understanding of the relation between the weld pool geometry, the stress distribution and the solidification cracking, a three-dimensional computational fluid dynamic (CFD) model was combined with a thermo-mechanical model. The CFD model was employed to analyze the flow of the molten metal in the weld pool during the laser beam welding process. The weld pool geometry estimated from the CFD model was used as a heat source in the thermal model to calculate the temperature field and the stress development and distributions. The CFD results showed a bulging region in the middle depth of the weld and two narrowing areas separating the bulging region from the top and bottom surface. The thermo-mechanical simulations showed a concentration of tension stresses, transversally and vertically, directly after the solidification during cooling in the region of the solidification cracking.
The performance and safety of welded high-strength low-alloyed steel (HSLA) components are substantially affected by the stresses occurring during and after welding fabrication, especially if welding shrinkage and distortion are severely restrained. The surrounding structure of the whole component affects loads in the far-field superimposing with welding stresses in the near-field of the weld. In this study a unique testing facility was used to restrain shrinkage and bending while analyse multiaxial far-field loads (max. 2 MN) during assembly of thick-walled component. A novel approach for the assessment of the in-situ-measured far-field data in combination with the actual weld geometry was elaborated. For the first time, analyses of the global bending moments of restrained welds based on the neutral axis of the actual weld load bearing section were achieved. Hence, far-field measurements offered the possibility to determine critical near-field stresses of the weld crosssections for the entire joining process. This work presents the approach for far-to-near field in-situ determination of stresses in detail for the 2-MN-testing system based on an extensive experimental work on HSLA steel welds, which demonstrates sources and consequences of these high local welding stresses. Thus, it was clarified, why the first weld beads are crucial regarding welding stresses and cold cracking, which is well known, but has never been measured so far. Accompanying analyses using X-ray diffraction (XRD) after welding show effects on local residual stress distributions. These analyses indicated viable prospects for stress reduction during assembly of thick-walled HSLA steel components.
Additive Manufacturing (AM) through the Selective Laser Melting (SLM) route offers ample scope for producing geometrically complex parts compared to the conventional subtractive manufacturing strategies. Nevertheless, the residual stresses which develop during the fabrication can limit application of the SLM components by reducing the load bearing capacity and by inducing unwanted distortion, depending on the boundary conditions specified during manufacturing. The present study aims at characterizing the residual stress states in the SLM parts using different diffraction methods. The material used is the nickel based superalloy Inconel 718. Microstructure as well as the surface and bulk residual stresses were characterized. For the residual stress analysis, X-ray, synchrotron and neutron diffraction methods were used. The measurements were performed at BAM, at the EDDI beamline of -BESSY II synchrotronand the E3 line -BER II neutron reactor- of the Helmholtz-Zentrum für Materialien und Energie (HZB) Berlin. The results reveal significant differences in the residual stress states for the different characterization techniques employed, which indicates the dependence of the residual state on the penetration depth in the sample. For the surface residual stresses, longitudinal and transverse stress components from X-ray and synchrotron agree well and the obtained values were around the yield strength of the material. Furthermore, synchrotron mapping disclosed gradients along the width and length of the sample for the longitudinal and transverse stress components. On the other hand, lower residual stresses were found in the bulk of the material measured using neutron diffraction. The longitudinal component was tensile and decreased towards the boundary of the sample. In contrast, the normal component was nearly constant and compressive in nature. The transversal component was almost negligible. The results indicate that a stress re-distribution takes place during the deposition of the consecutive layers. Further investigations are planned to study the phenomenon in detail.
Submerged arc welded (SAW) components of creep-resistant low-alloyed Cr-Mo-V steels are used for thick-walled heavy petrochemical reactors (wall-thickness up to 475 mm) as well as employed in construction of modern high-efficient fossil fired power plants. These large components are accompanied by significant restraints during welding fabrication, especially at positions of different thicknesses like welding of nozzles. As a result, residual stresses occur, playing a domi-nant role concerning so-called stress relief cracking (SRC) typically during post weld heat treat-ment (PWHT). Besides specific metallurgical factors (like secondary hardening due to re-precipitation), high tensile residual stresses are a considerable influence factor on SRC. For the assessment of SRC susceptibility of certain materials mostly mechanical tests are applied which are isolated from the welding process. Conclusions regarding the influence of mechanical factors are rare so far. The present research follows an approach to reproduce loads, which occur during welding of real thick-walled components scaled to laboratory conditions by using tests designed on different measures. A large-scale slit specimen giving a high restraint in 3 dimensions by high stiffness was compared to a medium-scale multi-pass welding U-profile specimen showing a high degree of restraint in longitudinal direction and a small-scale TIG-re-melted specimen. The small-scale specimens were additionally subjected to mechanical bending to induce loads that are found during fabrication on the real-scale in heavy components. Results show for all three cases compa-rable high tensile residual stresses up to yield strength with high gradients in the weld metal and the heat affected zone. Those high tensile stresses can be significant for cracking during further PWHT.
Due to the increasing global demand for pure silver, native wire silver aggregates in very high purities are gaining more industrial attention. Up to the present, no substantial metallurgical Investigation of natural wire silver exists in the accessible literature. To convey urgently needed cross-disciplinary fundamental knowledge for geoscientists and metallurgical engineers, twenty natural wire silver specimens from eight different ore deposits have been investigated in detail for the first time by EBSD (Electron Back Scattering Diffraction), supported by light microscopy and micro-probe analyses. The improved understanding of the natural silver wire microstructure provides additional Information regarding the growth of natural silver aggregates in comparison to undesired artificial growth on electronic devices. Clear evidence is provided that natural silver curls and hairs exhibit a polycrystalline face-centered cubic microstructure associated with significant twinning. Although the investigated natural wire silver samples have relatively high purity (Ag > 99.7 wt.-%), they contain a variety of trace elements such as, S, Cu, Mn, Ni, Zn, Co and Bi, As and Sb. Additionally, Vickers micro-hardness measurements are provided for the first time which revealed that natural silver wires and curls are softer than it might be expected from conversion of the general Mohs hardness of 2.7.
Commercial grade-1 titanium samples (Ti, 99.6%) were treated using three alternative methods, (i) femtosecond laser processing, (ii) thermal heat treatment, and (iii) electrochemical anodization, respectively, resulting in the formation of differently conditioned superficial titanium oxide layers. The laser processing (i) was carried out by a Ti:sapphire laser (pulse duration 30 fs, central wavelength 790 nm, pulse repetition rate 1 kHz) in a regime of generating laser-induced periodic surface structures (LIPSS). The experimental conditions (laser fluence, spatial spot overlap) were optimized in a sample-scanning setup for the processing of several square-millimeters large surface areas covered homogeneously by these nanostructures. The differently oxidized titanium surfaces were characterized by optical microscopy, micro Raman spectroscopy, variable angle spectroscopic ellipsometry, and instrumented indentation testing. The tribological performance was characterized in the regime of mixed friction by reciprocating sliding tests against a sphere of hardened steel in fully formulated engine oil as lubricant. The specific tribological performance of the differently treated surfaces is discussed with respect to possible physical and chemical mechanisms.
Among the various welding technologies, resistance spot welding (RSW) and laser beam welding (LBW) play a significant role as joining methods for the automobile industry. The application of RSW and LBW for the automotive body alters the microstructure in the welded areas. It is necessary to identify the mechanical properties of the welded material to be able to make a reliable statement about the material behavior and the strength of welded components. This study develops a method by which to determine the mechanical properties for the weldment of RSW and LBW for two dual phase (DP) steels, DP600 and DP1000, which are commonly used for the automotive bodies. The mechanical properties of the resistance spot weldment were obtained by performing tensile tests on the notched tensile specimen to cause an elongation of the notched and welded area in order to investigate its properties. In order to determine the mechanical properties of the laser beam weldment, indentation tests were performed on the welded material to calculate its force-penetration depth-curve. Inverse numerical simulation was used to simulate the indentation tests to determine and verify the parameters of a nonlinear isotropic material model for the weldment of LBW. Furthermore, using this method, the parameters for the material model of RSW were verified. The material parameters and microstructure of the weldment of RSW and LBW are compared and discussed. The results show that the novel method introduced in this work is a valid approach to determine the mechanical properties of welded high-strength steel structures. In addition, it can be seen that LBW and RSW lead to a reduction in ductility and an increase in the amount of yield and tensile strength of both DP600 and DP1000.
Hybrid laser-arc welding offers many advantages, such as deep penetration, good gap bridge-ability, and low distortion due to reduced heat input. The filler wire which is supplied to the process is used to influence the microstructure and mechanical properties of the weld seam.
A typical problem in deep penetration high-power laser beam welding with filler wire and hybrid laser-arc welding is an insufficient mixing of filler material in the weld pool, leading to a non-uniform element distribution in the seam. In this study, oscillating magnetic fields were used to form a non-conservative component of the Lorentz force in the weld pool to improve the element Distribution over the entire thickness of the material. Full penetration hybrid laser-arc welds were performed on 20-mm-thick S355J2 steel plates with a nickel-based wire for different arrangements of the oscillating magnetic field. The Energy-dispersive X-ray spectroscopy (EDS) data for the distribution of two tracing elements (Ni and Cr) were used to analyze the homogeneity of dilution of the filler wire.
With a 30° turn of the magnetic field to the welding direction, a radical improvement in the filler material distribution was demonstrated. This would lead to an improvement of the mechanical properties with the use of a suitable filler wire.
The advantage of selective laser melting (SLM) is its high accuracy and geometrical flexibility.
Because the maximum size of the components is limited by the process chamber, possibilities must be found to combine several parts manufactured by SLM. An application where this is necessary, is, for example, the components of gas turbines, such as burners or oil return pipes, and inserts, which can be joined by circumferential welds. However, only a few investigations to date have been carried out for the welding of components produced by SLM. The object of this paper is, therefore, to investigate the feasibility of laser beam welding for joining SLM tube connections made of nickel-based alloys.
For this purpose, SLM-manufactured Inconel 625 and Inconel 718 tubes were welded with a Yb:YAG disk laser and subsequently examined for residual stresses and defects. The results showed that the welds had no significant influence on the residual stresses. A good weld quality could be achieved in the seam circumference. However, pores and pore nests were found in the final overlap area, which meant that no continuous good welding quality could be accomplished. Pore formation was presumably caused by capillary instabilities when the laser power was ramped out.