Numerical investigations on the influence of the weld surface and die geometry on the resulting tensile stresses in the joining zone during an extrusion process

Behrens, Bernd‐Arno; Duran, Deniz; Uhe, Johanna; Matthias, Thorsten

doi:10.25518/esaform21.919

Cited by 3 publications

(6 citation statements)

References 8 publications

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“…Thermo-mechanical material modelling. In order to describe the material behaviour of the used aluminium EN AW-6082, flow curves are taken from previous work [5]. For the 100Cr6, flow curves from Simufact Forming 16.0 database are used to model the steel.…”

Section: Methodsmentioning

confidence: 99%

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Modelling failure of joining zones during forming of hybrid parts

Wester¹

2023

Materials Research Proceedings

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Abstract. Combining diverse materials enables the use of the positive properties of the individual material in one component. Hybrid material combinations therefore offer great potential for meeting the increasing demand on highly loaded components. The use of hybrid pre-joined semi-finished products simplifies joining processes through the use of simple geometries. However, the use of pre-joined hybrid semi-finished products also results in new challenges for the following process chain. For example, the materials steel and aluminium may form brittle intermetallic phases in the joining zone, which can be damaged in the following forming process under the effect of thermo-mechanical loads and thus lead to a weak point in the final part. Due to their small thickness as well as their position in the component, the analysis of the joining zone is only possible by complex destructive testing methods. FE simulation therefore offers an efficient way to analyse the development of damage in the process design and to reduce damage by process modifications. Therefore, within this study a damage model based on cohesive zone elements is implemented in the FE software MSC Marc 2018 and calibrated using experimental local tensile tests performed under process relevant conditions.

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Section: Methodsmentioning

confidence: 99%

“…Therefore, it requires special consideration. Previous investigations show that during impact extrusion critical tensile stresses occur within the joining zone which can lead to local rupture [5]. However, the joining zone within the process as well as in the final component can only be analysed at great expense and in destructive tests.…”

Section: Introductionmentioning

confidence: 99%

Modelling failure of joining zones during forming of hybrid parts

Wester¹

2023

Materials Research Proceedings

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“…The required material properties for the 100Cr6 were taken from previous work [9]. Boundary conditions like current in the induction coil and the frequency were derived from experimental inductive heating tests, which are described in detail in [7]. During heating, only the steel is heated inductively, the aluminium is heated by thermal conduction.…”

Section: Methodsmentioning

confidence: 99%

Numerical Process Design for the Production of a Load-Adapted Hybrid Bearing Bushing

Uhe,

Wester,

Behrens

2023

KEM

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Due to increasing product requirements regarding lightweight, functional integration and resource efficiency, research into and use of hybrid parts are steadily increasing. Tailored Forming provides an innovative process chain for manufacturing hybrid parts by using pre-joined semi-finished products. In addition to the potentials, however, challenges also result in the production of hybrid components. In particular, the material combination of steel and aluminium is demanding due to strongly differing physical properties. An inhomogeneous temperature distribution within the pre-joined semi-finished part can be used to equalize flow properties during the forming process. However, processes are sensitive to temperature deviations resulting in critical stresses and failure of the final part. This study focuses on a process design of a hybrid bearing bushing consisting of the aluminium alloy EN-AW-6082 and the steel 100Cr6 using numerical simulation. First, a closed-die forging process is analysed regarding sensitivity to process fluctuations resulting in deviations in temperature distribution. To increase process stability, a new hollow forward-impact extrusion process is numerically designed and investigated regarding its potential to reduce critical stresses and thus the risk of part failure. Furthermore, a numerical model of inductive heating is used for the consideration of inhomogeneous temperature fields. Finally, hybrid bearing bushings are produced using closed-die forging and hollow-forward extrusion to evaluate numerical results.

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“…Friction joining leads to a thin and brittle intermetallic phase, which is formed between the monolithic materials steel and aluminium. Due to the significantly diverging flow behaviour of steel and aluminium critical tensile stresses can occur during the forming process, which can lead to damage or complete rupture of the joining zone [5]. To reduce or completely avoid tensile stresses, the flow stress levels need to be equalised as far as possible by targeted inhomogeneous heating by induction.…”

Section: Introductionmentioning

confidence: 99%

“…To reduce or completely avoid tensile stresses, the flow stress levels need to be equalised as far as possible by targeted inhomogeneous heating by induction. In addition, the occurrence of critical stresses can be resisted by the targeted application of counterforces [5]. However, the joining zone within the process as well as in the final component can only be analysed at great expense and in destructive tests.…”

Section: Introductionmentioning

confidence: 99%

Numerical Process Analysis of Forming Semi-Finished Hybrid Parts

Wester,

Behrens

2023

KEM

Self Cite

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Increasing demands on component functionality and weight, but also on the use of resources and cost-effectiveness, are leading to the increased use of hybrid components. The combination of diverse materials enables the use of positive properties of the individual material in one component. With regard to the production of hybrid components, the use of hybrid pre-joined semi-finished parts simplifies the joining process, as simple geometries can be used. A well-established process for joining dissimilar materials such as steel and aluminium is rotary friction welding. However, steel and aluminium form brittle intermetallic phases in the joining zone due to their low solubility. Therefore, in addition to the advantages, the use of pre-joined hybrid semi-finished parts also pose new challenges for the following process chain. As a result of thermomechanical stresses during forming, local failure of the joining zone may occur. Due to its small thickness and position within the component, the analysis of the joining zone is only possible by complex destructive testing methods. FE simulation therefore offers an efficient way to design and analyse forming processes for hybrid semi-finished parts, the development of damage in the process design and to reduce damage by process modifications. Therefore, within this study a numerical model of the forming process chain is developed considering inductive heating, transfer and forming. For a realistic description the flow behaviour of the monolithic materials as well as the bonding strength of the pre-joined semi-finished parts is determined in experimental tests. Based on the experiments a damage model is calibrated and used for the analysis of different process variants of hollow forward extrusion of pre-joined hybrid semi-finished parts of steel and aluminium.

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Numerical investigations on the influence of the weld surface and die geometry on the resulting tensile stresses in the joining zone during an extrusion process

Cited by 3 publications

References 8 publications

Modelling failure of joining zones during forming of hybrid parts

Modelling failure of joining zones during forming of hybrid parts

Numerical Process Design for the Production of a Load-Adapted Hybrid Bearing Bushing

Numerical Process Analysis of Forming Semi-Finished Hybrid Parts

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