Belgian Welding Institute

Gent, Belgium

Belgian Welding Institute

Gent, Belgium
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Huysmans S.,Engie Laboratory Laborelec | Vekeman J.,Belgian Welding Institute | Hautfenne C.,Engie Laboratory Laborelec
Welding in the World | Year: 2017

Modern and future power plants will use more complex materials to withstand the higher steam temperatures and pressures as well as thermal cycling. As such, dissimilar metal welds (DMWs) will be more widespread in new design than before and will need to demonstrate resistance to combinations of severe creep, corrosion/oxidation, and low cycle fatigue. The DMWs between different steels or alloys are an underestimated topic. Experienced and documented premature failures reveal the criticality of DMWs. This study focused on the DMWs between 9Cr martensitic creep strength enhanced ferritic steels and advanced austenitic stainless steels. Two collaborative projects related to 18%Cr and 25%Cr austenitic creep resisting stainless steel delivered data concerning base metal characterization and weldability of similar and dissimilar welding. The specific features of dissimilar welding are further approached in more detail in this analysis. Two main methodologies, i.e., direct welding and buttering techniques using different filler metals were investigated and characterized via uniaxial creep rupture testing and metallographic examination particularly focusing on the fusion line carbide formation and morphology. For the limited exposure times of 10 kh in this project, the results show that aligned and coarse type I carbide formation is occurring at the 9Cr fusion line between A617 type weld metal. The selection of P87 or A82 type filler metals demonstrated isolated to partly aligned carbides, respectively, at the fusion line. To mitigate the risk to corrosion and achieve a marginal increase in creep performance, buttering techniques are recommended. © 2016, International Institute of Welding.


Kwee I.,Belgian Welding Institute | Faes K.,Belgian Welding Institute
Welding and Cutting | Year: 2017

The current trend to reduce weight and fuel consumption within the automotive industry has resulted in multi-material designs, which allow to exploit the optimal material with desired properties for each part of the automotive component. However, the next generation of novel hybrid me - tal-composite components poses major challenges regarding the joints between metals and composites. This was the driving force behind the "MetalMorphosis" research project, which addressed different joint design concepts for metal-composite tubular and sheet joints, using the electromagnetic pulse technology. The acquired knowledge was validated at an industrial level by manufacturing a hybrid metal-composite brake pedal.


Coppieters S.,Catholic University of Leuven | Zhang H.,Catholic University of Leuven | Xu F.,Catholic University of Leuven | Vandermeiren N.,Belgian Welding Institute | And 2 more authors.
Materials and Design | Year: 2017

Lightweight and high strength sheet metal such as aluminum alloy sheets are used in a variety of industrial applications. Due to the limited weldability of these materials, mechanical joining techniques such as clinching are of interest. The challenge in this regard is that conventional round clinch forming locally induces large plastic deformations which potentially cannot be accommodated by materials with limited ductility. Ductile damage models are used to predict the occurrence of bottom cracks during conventional round clinch forming of EN AW-6082 T6 sheet. It is shown that cracks in the bottom of a clinched joint and the final static strength of a single lap shear specimen can be numerically reproduced provided that the post-necking strain hardening behavior and damage behavior of the base material are properly identified. The observed bottom cracks did not have a detrimental effect on the static strength and fatigue life of single shear lap specimens. It is hypothesized that fatigue cracks in single shear lap tests initiate due to fretting. © 2017 Elsevier Ltd


Verleysen P.,Ghent University | Peirs J.,Ghent University | Van Slycken J.,Ghent University | Faes K.,Belgian Welding Institute | Duchene L.,University of Liège
Journal of Materials Processing Technology | Year: 2011

The strain rate dependence of plastic yield and failure properties displayed by most metals affects energies, forces and forming limits involved in high speed forming processes. This paper investigates the influence of the strain rate on the forming properties of one laboratory made and three commercial steel grades: a CMnAl TRIP steel, the ferritic structural steel S235JR, the drawing steel DC04 and the ferritic stainless steel AISI 409. First, split Hopkinson tensile bar (SHTB) experiments are carried out to assess the influence of the strain rate on the materials' stress-strain curves. Subsequently, the obtained SHTB results, together with static tensile test results, are used to model the constitutive behaviour of the investigated steels using the phenomenological Johnson-Cook (JC) model and the Voce model, thus allowing dynamic modelling of forming processes. Finally, forming limit diagrams (FLDs) are calculated using the Marciniak-Kuczynski method. The results clearly show that the effect of the strain rate on forces and energies involved in a forming process, and the forming limits is non-negligible and strongly material dependent. © 2011 Elsevier B.V. All rights reserved.


Faes K.,Belgian Welding Institute | Zaitov O.,Belgian Welding Institute | De Waele W.,Ghent University
ASM Proceedings of the International Conference: Trends in Welding Research | Year: 2013

In magnetic pulse welding, electromagnetic forces are used to deform, accelerate and weld workpieces. The process is mostly used for tubular specimens. In this study, experiments were performed to investigate the weldability of various material combinations. The weld quality was assessed based on metallographic examinations, scanning electron microscopy and hardness measurements. The weld interface morphology, the intermetallic phases and the most common weld defects are described. Copyright © 2013 ASM International® All rights reserved.


Zaitov O.,Belgian Welding Institute | Kolchuzhin V.A.,TU Chemnitz
Journal of Manufacturing Processes | Year: 2014

Electromagnetic pulse metal processing techniques (EPMPT) such as welding, forming and cutting have proven to be an effective solution to specific manufacturing problems. A high pulse magnetic field coil is a critical part of these technologies and its design is a challenging task. This paper describes a Bitter coil design using a newly developed methodology for a simplified analytical calculation of the coil and complementary finite element models (FE) of different complexity. Based on the methodology a Belgian Welding Institute (BWI) Bitter coil has been designed and tested by means of short circuit experiments, impedance and B-field measurements. A good agreement between the calculated and the experimental design parameters was found. © 2014 The Society of Manufacturing Engineers.


Vekeman J.,Belgian Welding Institute | Huysmans S.,GDF SUEZ | Hautfenne C.,GDF SUEZ
Welding in the World | Year: 2016

The modern Ultra Super Critical Power Plants (USC PP) applying the 600 °C technology require advanced stainless steels in superheater/reheater systems in order to cope with the increased steam parameters. Different grades of stainless steels have been developed by increasing Cr-contents, alloying with stabilizing and precipitating elements as well as thermomechanical heat treatments resulting in high creep rupture strengths and improved oxidation/corrosion resistance. In the context of a collaborative research project, X6CrNiNbN25-20 (DMV310N/HR3C) has been investigated. The main focus of the research project was on characterization and weldability assessment. As a result, the base metal under investigation was compared with governing code cases and specifications. Base metal chemical composition, microstructures, mechanical properties, reheat cracking sensitivity, and hot ductility as well as creep rupture strengths have been investigated. A weldability assessment, including thermal simulation and welding procedure qualifications, has been performed to establish parameter windows for similar and dissimilar welding. Dissimilar welding between grade 92 and austenitic steel tubes has been performed. The project also took the opportunity to investigate the behavior of a recently developed gas tungsten arc welding (GTAW) P87 consumable for dissimilar welding. Cross-weld creep rupture tests have been conducted for both similar and dissimilar welding, while aging tests addressed microstructural stability. © 2016, International Institute of Welding.


Vekeman J.,Belgian Welding Institute | Huysmans S.,GDF SUEZ | De Bruycker E.,GDF SUEZ
Welding in the World | Year: 2014

The modern (USC PP) applying the 600 °C technology require advanced austenitic stainless steels in superheater/reheater systems in order to cope with the increased steam parameters. Different grades of austenitic stainless steels have been developed by increasing Cr contents, alloying with stabilizing and precipitating elements as well as thermomechanical heat treatments resulting in high creep rupture strengths and improved oxidation/corrosion resistance. In the context of a collaborative research project, DMV304HCu (X10CrNiCuNb18-9-3) has been selected. The main focus of the research project was on characterization and weldability assessment. As a result, the base metal under investigation was compared with governing code cases and specifications. Base metal chemical composition, microstructures, mechanical properties, reheat cracking sensitivity, hot ductility as well as creep rupture strengths have been investigated. A weldability assessment, including thermal simulation and welding procedure qualifications, has been performed to establish parameter windows for similar and dissimilar welding. Dissimilar welding between Grade 92 and austenitic stainless steel tubes has been performed. The project also took the opportunity to investigate the behavior of a recently developed gas tungsten arc welding (GTAW) P87 consumable for dissimilar welding. Cross-weld creep rupture testing has been conducted for both similar and dissimilar welding, and aging tests addressed microstructural stability. © 2014, International Institute of Welding.


Kwee I.,Belgian Welding Institute | Faes K.,Belgian Welding Institute
Key Engineering Materials | Year: 2016

This study investigated joining of Al to Cu sheets by electromagnetic pulse welding, which is a solid-state welding process that uses electromagnetic forces to join materials. The interfacial morphology and mechanical properties of the Al/Cu joints were analysed and related to the welding process parameters and weld properties. The centre section of the Al/Cu joints evolved from a non-welded to a welded zone. The welded zone started with a wavy interface, consisting of thick interfacial layers with defects and evolved to a relatively flat interface without an interfacial layer. The interfacial layer thickness is determined by both the discharge energy and the stand-off distance. A higher tensile force, up to 4.9 kN, was achieved at a higher energy and a lower stand-off distance of 2 mm. The tensile force is directly related to the weld width, since a higher tensile force is achieved for a higher weld width. In addition, the presence of interfacial layers can contribute to a small extent to a higher tensile force. © 2016 Trans Tech Publications, Switzerland.


Deplus K.,Catholic University of Louvain | Simar A.,Catholic University of Louvain | Haver W.V.,Belgian Welding Institute | Meester B.D.,Catholic University of Louvain
International Journal of Advanced Manufacturing Technology | Year: 2011

Residual stresses are detrimental to the fatigue, fracture and corrosion resistance of welds. The literature on residual stress measurements in aluminium alloy friction stir welds is reviewed. The results of a large number of longitudinal residual stress measurements performed by the slitting method on friction stir welds in 2024-T3, 6082-T6 and 5754-H111 aluminium alloys are compared and their origin discussed. From the current investigation, it can be derived that the type of machine used for welding has only little influence on the residual stress profile. The influence of alloy type and welding parameters on the magnitude of the residual stresses and the shape of their distribution across the weld is investigated. Their magnitude is far below the room temperature yield strength of the base material. A distribution with an "M-shape" is always found on age hardenable structural alloys (albeit more pronounced in 6082-T6 alloy than in 2024-T3 alloy), while a "plateau" is found in the case of the strain hardenable 5754 H111 alloy. The low magnitude and the differences in distribution of the longitudinal residual stress are attributed mainly to the microstructural changes in the weld centre and are discussed based on the hardness profiles performed across the welds. The paper also discusses the reasons why those results are in disagreement with a number of numerical simulations from the literature that do not account for the influence of the welding thermomechanical history on the material microstructure and properties. © 2011 Springer-Verlag London Limited.

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