Examination of Friction Coefficient in Friction Welding Process of Tubular Steel Elements

Ambroziak, Andrzej; Winnicki, Marcin; Laska, P.; Lachowicz, M.; Zwierzchowski, M.; Leśniewski, J.

doi:10.2478/v10172-011-0107-8

Cited by 4 publications

(5 citation statements)

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“…Where M < refers to the friction torque in Nm, P < is the pressure force in N and r is the radius of the cylindrical welded specimen, considered as 8 mm in the study [34]. It was concluded that the friction coefficient was maximised in the low temperature range and was stabilised at 0.3 after reaching above 400°C.…”

Section: Boundary Conditionsmentioning

confidence: 98%

“…The coefficient of friction is a significant component in calculating the heat generation between two surfaces. Different researchers have estimated different values for different material interactions under specific conditions [33,34]. Nandan et al [33] computed the friction coefficient by considering the relative velocity between rotating tool and workpiece and used a value of 0.4.…”

Section: Boundary Conditionsmentioning

confidence: 99%

“…Nandan et al [33] computed the friction coefficient by considering the relative velocity between rotating tool and workpiece and used a value of 0.4. Furthermore, Ambroziak et al [34] determined the friction coefficient "µ" for steel S235 from equation 7:…”

Section: Boundary Conditionsmentioning

confidence: 99%

“…It was concluded that the friction coefficient was maximised in the low temperature range and was stabilised at 0.3 after reaching above 400°C. The value of friction coefficient slightly decreased with increasing temperature [34]. Consequently, a constant friction coefficient value of 0.3 has been used in this study for both weld models.…”

Section: Boundary Conditionsmentioning

confidence: 99%

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Advanced numerical modelling of friction stir welded low alloy steel

Ahmad

Galloway

Toumpis

2018

Journal of Manufacturing Processes

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The development of advanced joining processes such as friction stir welding (FSW) is necessary to maintain manufacturing competitiveness in any industrial nation. Substantial research that has been carried out on FSW of aluminium alloys has demonstrated considerable benefits; this has led to greater interest in FSW of steel and other high melting temperature alloys. In this context, numerical modelling can provide costeffective development of steel FSW. Due to the limitations associated with the Johnson Cook model when employed in high melting temperature metals, a three-dimensional thermo-mechanical simulation of FSW featuring low alloy steel with previously generated experimental temperature dependant properties has been successfully solved in Abaqus/Explicit. Unlike any previous research in which either the workpiece is assumed as a high viscous body or the tool is modelled as a moving heating source, the Coupled Eulerian Lagrangian approach has been innovatively applied to model the FSW process on steel. All stages of FSW (plunge, dwell and traverse) have been modelled for slow and fast process parameters and their results compared with previous experimental work on the same grade of steel. In each model, the weld shape and weld surface flash were found to be in exceptionally close alignment with previous experimental results.Recently, the Coupled Eulerian Lagrangian (CEL) approach has been used to successfully model FSW of aluminium with minimum assumptions (solid tool instead of virtual heat source and solid workpiece instead of viscous fluid body) in order to visualise more realistic results [25,26]. In both ALE and CEL approaches, Johnson Cook's (JC) material properties of aluminium have been used in the literature to model the FSW process. Johnson Cook's model calculates several constants for monitoring the material's behaviour. When using the JC model, the welding process is initiated after the material temperature is raised to a theoretically calculated JC melting temperature that is different from the actual melting temperature of the material. For the case of aluminium, the JC model yields approximately realistic results as the JC melting temperature for aluminium lies in the range of 75-85% of its actual melting temperature

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Section: Boundary Conditionsmentioning

confidence: 98%

Section: Boundary Conditionsmentioning

confidence: 99%

Section: Boundary Conditionsmentioning

confidence: 99%

Section: Boundary Conditionsmentioning

confidence: 99%

See 2 more Smart Citations

Advanced numerical modelling of friction stir welded low alloy steel

Ahmad

Galloway

Toumpis

2018

Journal of Manufacturing Processes

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“…All model settings were replicated from the model FSW -1, also referred as the fast weld model in the previous research [26]. The entire workpiece was assigned a fixed initial temperature of 25 o C. A frictional coefficient of 0.3 was used to provide a feasible contact property definition between all surfaces, as discussed in previous studies [26,31]. To transfer the heat from workpiece to the surrounding, convective coefficients of 10 and 2000 W/m 2 K were applied on the top/sides and bottom surfaces of the workpiece, respectively.…”

Section: Initial and Boundary Conditionsmentioning

confidence: 99%

Numerical optimisation of laser assisted friction stir welding of structural steel

Ahmad

Galloway

Toumpis

2019

Science and Technology of Welding and Joining

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Significant progress has been made on the implementation of friction stir welding (FSW) in the industry for aluminium alloys. However, steel FSW and other high temperature alloys is still the subject of considerable research, mainly because of the short life and high cost of the FSW tool. Different auxiliary energies have been considered as a means of optimising the FSW process and reducing the forces on the tool during the plunge and traverse stages, but numerical studies on steel are particularly limited. Building on the state-of-art, laser assisted steel FSW has been numerically developed and analysed as a viable process amendment. Laser assisted FSW increased the traverse speed up to 1500 mm/min, significantly higher than conventional steel FSW. The application of laser assistance with a distance of 20 mm from the rotating tool reduced the reaction force on the tool probe tip up to 55% as compared to standard FSW.

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