Datei im Netzwerk der BAM verfügbar ("Closed Access")
Filtern
Erscheinungsjahr
Dokumenttyp
- Zeitschriftenartikel (45)
- Vortrag (43)
- Beitrag zu einem Tagungsband (18)
- Posterpräsentation (3)
- Corrigendum (2)
- Beitrag zu einem Sammelband (1)
- Forschungsbericht (1)
Schlagworte
- Residual stress (29)
- Eigenspannungen (20)
- Welding (19)
- Residual stresses (16)
- Schweißen (11)
- LTT (10)
- Martensite (9)
- Restraint (9)
- Additive manufacturing (8)
- High-strength steels (8)
- Hochfester Stahl (8)
- Neutron diffraction (8)
- Phase transformation (8)
- MAG-Schweißen (6)
- Process parameters (6)
- Additive Fertigung (5)
- High strength steel (5)
- Solidification cracking (5)
- Synchrotron (5)
- Additive Manufacturing (4)
- DED-arc (4)
- Dilatometry (4)
- High-strength steel (4)
- IN718 (4)
- Low transformation temperature (4)
- Residual Stress (4)
- Schwingfestigkeit (4)
- Selective laser melting (4)
- Stress relief cracking (4)
- Transformation (4)
- Varestraint-Test (4)
- Creep-resistant steel (3)
- Kaltrisssicherheit (3)
- MAG welding (3)
- Microstructure and texture (3)
- Post weld heat treatment (3)
- Residual Stresses (3)
- Selective Laser Melting (3)
- Wasserstoff (3)
- AISI D2 (2)
- Austenite (2)
- Bauteilprüfung (2)
- Cold cracking (2)
- Cracking (2)
- Creep resistant steel (2)
- EDXRD (2)
- GMA welding (2)
- Heißrisse (2)
- Hochfeste Feinkornbaustähle (2)
- Hot cracking (2)
- LTT-Zusatzwerkstoff (2)
- Large scale test (2)
- Large-scale test (2)
- Laser implantation (2)
- Martensit (2)
- Phase Transformation (2)
- Phasenumwandlung (2)
- SLM (2)
- Schweißprozessparameter (2)
- Submerged arc welding (2)
- Surface texturing (2)
- Synchrotron X-ray diffraction (2)
- Synchrotron diffraction (2)
- TRIP steel (2)
- Temperature (2)
- TiB2 (2)
- Varestraint test (2)
- Weldability (2)
- Windenergie (2)
- Wärmeführung (2)
- X-ray diffraction (2)
- hochfester Stahl (2)
- 13CrMoV9-10 (1)
- ADXRD (1)
- Aluminium alloys (1)
- Austenite stability (1)
- Bauteiltest (1)
- Bauteilversuch (1)
- Beanspruchungen (1)
- Bragg-edge neutron 2D imaging (BENI) (1)
- Brittle fracture (1)
- CCT diagrams (1)
- Carbon arc-air gouging (1)
- Component test (1)
- Component welding (1)
- Coordinate measurement machine (1)
- Crystallographic texture control (1)
- Diffraction (1)
- Digital image correlation (1)
- Dilution (1)
- Duplex Stainless Steel (1)
- Einspanngrad (1)
- Einspannung (1)
- Electron back-scattered diffraction (1)
- Electron backscatter diffraction (EBSD) (1)
- Energy dispersive X-ray diffraction (EDXRD) (1)
- Energy dispersive synchrotron X-ray diffraction (1)
- Erstarrungsriss (1)
- Erstarrungsrisse (1)
- Fatigue (1)
- Fatigue improvement (1)
- Fatigue strength (1)
- Fatigue testing (1)
- Ferrite (1)
- Filler materials (1)
- GMAwelding (1)
- GTA welding (1)
- Girders (1)
- Heat (1)
- Heat Control (1)
- Heat-affected zone (1)
- Heißriss (1)
- High energy synchrotron diffraction (1)
- High energy synchrotron radiation (1)
- High strength steels (1)
- High strength structural steels (1)
- High-strength structural steels (1)
- Hochdruck (1)
- Hydrogen (1)
- Hydrogen assisted cracking (1)
- Hydrogen embrittlement (1)
- Hydrogen-assisted cracking (1)
- Höherfester Feinkornbaustahl (1)
- IN718 PBF-LB/M (1)
- In situ synchrotron X-ray diffraction (1)
- In-situ diffraction (1)
- In-situ synchrotron X-ray diffraction (1)
- In718 (1)
- Influence (1)
- Interpass temperature (1)
- Kaltriss (1)
- Kaltrissbildung (1)
- LTT filler material (1)
- LTT filler materials (1)
- LTT weld filler materials (1)
- Laboratory X-ray diffraction (1)
- Laser powder bed fusion (1)
- Localized laser dispersing (1)
- Low (1)
- Low Transformation Temperature (1)
- Low temperature (1)
- Low temperature transformation (1)
- Low themperature (1)
- Low transformation (1)
- Low transformation temperature filler material (1)
- Low transformation temperature filler materials (1)
- MAG Welding (1)
- Martensite transformation (1)
- Martensitic stainless steel (1)
- Martensitic transformation (1)
- Martensitumwandlung (1)
- Materialprüfung (1)
- Metal additive manufacturing (MAM) (1)
- Microalloyed Steels (1)
- Mill scale (1)
- Modifizierter Sprühlichtbogen (1)
- Multi-pass welding (1)
- Multi-run weld (1)
- Multilayer Welding (1)
- Neutronenbeugung (1)
- Neutronenstreuung (1)
- Nickel-based superalloy (1)
- Nickel-based superalloys (1)
- Numerical Simulation (1)
- Offshore (1)
- Offshore steel (1)
- Offshore wind turbine (1)
- Phase transformation temperature (1)
- Pipeline (1)
- Probengeometrie (1)
- Prüfung (1)
- Radiography (1)
- Reaction force (1)
- Real-time operation (1)
- Reheat cracking (1)
- Repair welding (1)
- Reparatur (1)
- Retained Austenite (1)
- Retained austenite (1)
- Reversed austenite (1)
- Röntgendiffraktometrie (1)
- Scan strategies (1)
- Schweißeigenspannungen (1)
- Schweißzusatzwerkstoff (1)
- Sectioning method (1)
- Selektives Laserschmelzen (1)
- Shrinkage restraint (1)
- Spannungsrelaxationsrisse (1)
- Stress (1)
- Structural stiffness (1)
- Sub-Merged Arc Welding (1)
- Support configurations (1)
- Synchrotron Diffraction (1)
- Temperature alloys (1)
- Tensile tests (1)
- Testing (1)
- TiC (1)
- TiN (1)
- Transformation-induced plasticity (TRIP) (1)
- Varestraint testing (1)
- Vickers hardness (1)
- WRC 92 (1)
- Warmfester Stahl (1)
- Weld Filler Materials (1)
- Weld filler (1)
- Welded joints (1)
- Welding residual stress (1)
- Welding residual stresses (1)
- Welding simulation (1)
- Wire (1)
- Wire Arc Additive Manufacturing (1)
- X-Ray Diffraction (XRD) (1)
- XRD (1)
- μCT-analysis (1)
Organisationseinheit der BAM
- 9 Komponentensicherheit (65)
- 9.4 Integrität von Schweißverbindungen (65)
- 9.2 Versuchsanlagen und Prüftechnik (23)
- 8 Zerstörungsfreie Prüfung (10)
- 8.5 Röntgenbildgebung (9)
- 5 Werkstofftechnik (8)
- 5.0 Abteilungsleitung und andere (8)
- 9.0 Abteilungsleitung und andere (7)
- 9.3 Schweißtechnische Fertigungsverfahren (2)
- 5.1 Mikrostruktur Design und Degradation (1)
Eingeladener Vortrag
- nein (43)
Next to chemical composition, metallurgy and welding parameters, the intensity of restraint is one of the variables influencing solidification cracking. Tests like the Houldcroft Test, rate the hot cracking susceptibility indirectly on the amount of restraint the welding can endure without cracking. Modern lightweight steel construction welds can be subject to a larger amount of restraint due to their high-strength nature compared to classical use cases. By varying the plate thickness of Controlled Thermal Severity (CTS) tests produced out of S1100 QL, it was possible to vary the intensity of restraint on fillet welds at a high level. Testing was conducted with four different filler wires for Metal Active Gas (MAG) welding, including three solid and one metal-cored wire. In addition, two sets of welding parameters were tested. The first set with high heat input and high welding speed was shown to be more prone to solidification cracking compared to the second set with lower heat input and welding speed. The results show an increase in solidification cracking with increasing restraint severity.
This article focuses on the selective placement of additional LTT layers to generate compressive residual stresses in fatigue-critical areas of conventional weld joints. This enables an economical solution without effecting the integrity of welded joints. For this, longitudinal stiffeners made of high-strength steel were gas metal arc welded using conventional welding consumable in the first layer. Afterwards, a chromium-nickel alloyed LTT welding consumable was deposit on front sides of the stiffeners. By varying the welding parameters, different weld geometries of the LTT filler metal could be analyzed. The effects of additional LTT layers were investigated with regards to residual stresses, microstructure and strength. X-ray residual stresses measurements show that the residual stresses at the failure critical weld toe are significantly reduced by using additional LTT layers. While the conventional weld is characterized by tensile residual stresses, compressive residual stresses can be detected at the LTT weld. The level of residual stresses is influenced by the geometry of the LTT layer. Additional LTT layers with a high offset to the conventional weld generate more compressive residual stress in the HAZ than with a low offset. Therefore, the weld geometry has a considerable impact on the residual stress profile.
Influence of machining on residual stresses in additive manufactured high-strength steel components
(2024)
This study focuses on the effect of machining on the residual stresses and distortion of WAAM specimens. Defined specimens were welded fully automatically with a special WAAM solid wire (yield strength >820 MPa) with different geometric designs. The residual stresses state before and after cutting of the AM structure from the substrate plate were analyzed by means of X-ray diffraction on the specimen surface and complementary by 3d deformation analyses using photogrammetry. The results reveal significant influences of the geometry on the relaxation and redistribution of residual stresses.
MVT testing was conducted in Transvarestraint mode in multiple welding conditions and under a range of bending speeds. The materials observed were high strength filler metals used in GTAW namely DIN EN ISO 16834-A G 69 4 M21 Mn3Ni1CrMo (G69), 16834-A G 89 6 M21 Mn4Ni2CrMo (G89 6), 16834-A G 89 5 M21 Mn4Ni2,5CrMo (G89 5) and a filler wire 18276-A T 89 4 ZMn2NiCrMo M M21 1 H5 (T89). For evaluation light optical microscope pictures were used. Pixels containing cracks were manually segmented using a self-written program. Out of the segmented images data including crack length, position and area can be calculated for every crack. The results show dependencies of solidification cracking on the test parameters.
Diese Studie konzentriert sich auf den Einfluss der Bearbeitung auf die Eigenspannungen und den Verzug von WAAM-Proben. Definierte Proben wurden vollautomatisch mit einem speziellen WAAM-Massivdraht (Streckgrenze >820 MPa) mit unterschiedlichen geometrischen Designs geschweißt. Der Eigenspannungszustand vor und nach dem Abtrennen der AM-Struktur von der Substratplatte wurde mittels Röntgenbeugung an der Probenoberfläche analysiert und durch 3D-Verformungsanalysen mittels Photogrammetrie ergänzt. Die Ergebnisse zeigen einen signifikanten Einfluss der Geometrie auf die Relaxation und Umverteilung der Eigenspannungen.
Der Vortrag befasst sich mit der gezielten Einbringung zusätzlicher LTT-Lagen zur Erzeugung von Druckeigenspannungen in ermüdungskritischen Bereichen von konventionellen Schweißverbindungen. Dies ermöglicht eine wirtschaftliche Lösung, ohne die Integrität der Schweißverbindungen zu beeinträchtigen. Dazu wurden Längssteifen aus hochfestem Stahl in der ersten Lage mit konventionellem Schweißzusatzwerkstoff mittels Metall-Lichtbogenschweißen geschweißt. Anschließend wurde ein Chrom-Nickel-legierter LTT-Schweißzusatz auf die Stirnseiten der Steifen aufgebracht. Durch Variation der Schweißparameter konnten verschiedene Schweißnahtgeometrien des LTT-Zusatzwerkstoffs analysiert werden.
The weldability of stainless steels is largely controlled by the chemical composition, and alloys with ferritic or ferritic-austenitic solidification show the highest resistance to hot cracking. As the resulting phase balance also
affects the final properties, it may be beneficial to both foresee and measure the weld metal ferrite content. The WRC ’92 constitution diagram is currently the most accurate prediction tool available, but it does not take the cooling rate into consideration and the precision may be less accurate for stainless steels with high ferrite numbers (FN). This study aims to validate the reliability of the WRC ’92 diagram for weld metals with FN > 50. The chemical composition was altered through gas tungsten arc welding (GTAW) of UNS S32205 with ER347 filler wire that had been PVD-coated with either niobium (Nb), copper (Cu), nickel (Ni), manganese (Mn), carbon (C), or silicon (Si). The actual ferrite content was assessed using image analysis, FERITSCOPE® and X-ray diffraction (XRD). While the WRC ’92 diagram predictions were deemed accurate to acceptable for Ni, Si, and Mn, notable deviations were observed for Nb, Cu, and C. The FeriteScope exhibited a consistent trend with image analysis, though the values were higher, and scatter was wider, and the conversion factor is open for discussion. The lowest accuracy and largest spread were obtained using non-contact XRD, rendering it unsuitable for ferrite measurements of welds.
Large scale hydrogen assisted cracking test for thick walled SAW joints for offshore applications
(2023)
Offshore wind turbines continuously increase in size and weight and demand adequate offshore foundations concepts like monopiles, tripods or jackets. These components are typically submerged arc welded (SAW) high-strength thick steel plates like the S420ML. During welding, the occurrence of delayed hydrogen assisted cracking (HAC) must be anticipated. HAC is a critical combination of the local hydrogen concentration within a susceptible microstructure under certain mechanical load, i.e., the occurring (welding) residual stresses. The welding sequence of the thick-walled plates complicate the residual stress distribution due to the necessary repeated thermal cycling, i.e., welding seam / layer deposition to fill the joint. For that purpose, SAW with two-wire-technique was used to weld a specially designed and prototype-like mock-up of a real component with a thickness of 50 mm, filled more than 20 passes and a seam length of 1,000 mm. Additional welded stiffeners simulated the effect of a high restraint, to stimulate critical HAC conditions. The necessity of a minimum waiting time (MWT) before the NDT can be conducted (to exclude HAC) was critically verified by the application of ultrasonic testing of the welded joint at different time-steps of the NDT of 48 h after welding. The residual stresses were determined by a robot XRD goniometer. Tensile residual stresses up to the yield limit are found both in the weld metal and in the heat-affected zone. Numerical modelling allowed the qualitative estimation of the hydrogen diffusion in the weld. A remarkable HAC occurrence was not identified and proves both, a certain resistance of the weld joint to HAC and the (questionable) duration of the MWT.
Die schädigende Wirkung von Wasserstoff auf die mechanischen Eigenschaften von Stählen ist zwar bekannt, aber noch immer nicht ausreichend erforscht. Die schnelle und sichere Markteinführung von Wasserstofftechnologien macht es erforderlich, dieses Thema genauer zu untersuchen. Im Allgemeinen wird dies oft als Wasserstoffversprödung bezeichnet. Daher ist es wünschenswert, eine Prüfmethode zu entwickeln, die auf einfache Weise die Materialeigenschaften unter Wasserstoffatmosphäre ermitteln kann. Derzeit werden mechanische Prüfungen unter Wasserstoffatmosphäre in Autoklaven durchgeführt. Für diese Technik ist eine aufwendige Hardware erforderlich, daher sind die Prüfungen teuer und die Prüfkapazitäten nur in geringem Umfang verfügbar. Die hier vorgestellte Prüfmethode verspricht einen zukunftsweisenden Ansatz zur Reduzierung von Kosten und Bearbeitungszeiten durch die Verwendung von Hohlkörpern, d.h. die Probe selbst stellt den Autoklav dar.