Process analysis for magnetic pulse welding of aluminium-copper - - PowerPoint PPT Presentation

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Process analysis for magnetic pulse welding of aluminium-copper - - PowerPoint PPT Presentation

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Process analysis for magnetic pulse welding of aluminium-copper joints Verena Psyk, Christian Scheffler, Maik Linnemann, Dirk Landgrebe I 2 FG workshop on impulse metalworking 2016 December 1 st -2 nd , 2016 Nantes, France 1 Agenda

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Process analysis for magnetic pulse welding of aluminium-copper joints

Verena Psyk, Christian Scheffler, Maik Linnemann, Dirk Landgrebe I2FG workshop on impulse metalworking 2016 December 1st-2nd, 2016 Nantes, France

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Agenda

  • Introduction to the JOIN’EM project
  • Process analysis for magnetic pulse welding of aluminium-copper joints
  • Setup and process parameters
  • Welding experiments
  • Characterisation of the joint
  • Correlation of adjustable process parameters and weld quality
  • Quantification of collision parameters via numerical simulation
  • Correlation of collision parameters and weld quality
  • Summary

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SLIDE 3

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*Word cloud designed using Tagxedo

JOIN’EM – facts and figures

  • Titel

JOINing of copper to aluminium by ElectroMagnetic fields

  • Acronym

JOIN’EM

  • Duration

01.09.2015 - 31.08.2018

  • Budget

4.7 Mio. €

  • Grant

4.1 Mio. €

  • Coordinator Fraunhofer IWU (Dr.-Ing. Verena Psyk)
  • Project partners

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SLIDE 4
  • Supplementing the heavy use of full copper

components in applications related to electrical and thermal conductivity by hybrid copper – aluminium solutions

Reduce material costs Reduce product weight

  • Development of a flexible, highly productive, and

cost effective joining process for high quality dissimilar material joints magnetic pulse welding (MPW)

  • Enabling the industrial implementation of MPW and

facilitating the exploitation of known process advantages in series production

Jan 2000 Jul 2002 Jan 2005 Jul 2007 Feb 2010 Nov 2013 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 Aluminium Price in €/lb

(Source: www.infomine.com)

Copper

JOIN’EM – overall aims

Copper Aluminium Electrical conductivity 58 MS/m 36 MS/m Thermal conductivity 401 W/mK 236 W/mK Density 8.9 g/cm³ 2.7 g/cm³ Price 4.478 €/ton* 1.550 €/ton*

(Source: http://www.boerse-online.de/rohstoffe; 2016-11-04)

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SLIDE 5
  • Experimental and numerical process

analysis and design

  • Development of validated process and

joint design concepts

  • Development of multiscale simulation

strategies

  • Development of optimized tools for

industrial implementation

  • Development and automation of non-

destructive testing and quality control

  • Design, realization, and evaluation of

industrial demonstrators

  • Economic process and product evaluation

via life cycle cost analysis

  • Source: Calyos

Source: Whirlpool

  • HVAC

Source: Refco Source: Cegasa

  • Source: Alke

Fields of application and suggested demonstrators

JOIN’EM – objectives

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SLIDE 6

Setup and process parameters

Capacitor charging energy E (10 up to 40 kJ) Flyer thickness tflyer (0.3 up to 1.5 mm) Initial gap between flyer and target ginitial (1.0 up to 3.0 mm) x-position of the flyer edge xflyer (-2 up to +2 mm) Fixed parameters Capacitance C (300 µF) Target thickness ttarget (2 mm) x-position of target edge xtarget (14 mm) Free length l (16 mm) Width of flyer and target wflyer = wtarget (100 mm) Parameters considered for detailed investigation

Experimental setup Tool coil

Lactive= 100mm

Flyer (Cu-DHP) Coil conductor Spacer Target (EN AW-1050) Support

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SLIDE 7

Welding experiments

Tool coil (housing) Fixture (adjustable in height) Flyer Cu-DHP Exemplary welded part EN AW-1050

5 10 15 20 25 30

  • 400
  • 200

200 400 600 800 Time t in µs Current I in kA

Capacitor charging energy 10 kJ 15 kJ 20 kJ 30 kJ 40 kJ

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SLIDE 8

Characterization of the joint

  • Electrical resistance

measurement

  • Lap shear test
  • Metallographic

analysis

weld

Position of specimens in the hybrid sheet

Target: EN AW-1050 Flyer: Cu-DHP 100 micrograph 2 Specimen no. 3 75 190 1 10

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Characterization of the joint

  • Electrical resistance

measurement

  • Measurement points
  • Lap shear test
  • Metallographic

analysis Imposed current: I=4 A Measurement of voltage drop U Resistance of the joining partners is negligible if measurement points are close to the joining zone. Calculated resistance corresponds to resistance of the joint. Resistance

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SLIDE 10
  • Electrical resistance

measurement

  • Lap shear test
  • Metallographic

analysis

Characterization of the joint

Failure cases Force in kN 1 2 3 10 20 30

Base material aluminium copper Hybrid Al-Cu part

Elongation in mm Failure in the joint (occurs for all flyer thicknesses) Cu-DHP EN AW-1050 1 2 10 20 30

Base material aluminium copper Hybrid Al-Cu part

3 Elongation in mm Failure in the alumi- nium base material (occurs for flyer thick- nesses ≥ 1 mm) Cu-DHP EN AW-1050 Elongation in mm 1 2 10 20 30

Base material aluminium copper Hybrid Al-Cu part

3 Failure in the copper base material (occurs for flyer thick- nesses of 0.5 mm only) Cu-DHP EN AW-1050

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All cases: Welding of copper flyers to aluminium targets

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SLIDE 11
  • Electrical resistance

measurement

  • Lap shear test
  • Metallographic

analysis

Characterization of the joint

Width of the weld Start of the weld End of the weld

EN AW-1050 Cu-DHP

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Correlation of adjustable process parameters and weld quality

Maximum transferable force in a lap shear test is considered for mechanical joint characterisation

5 15 25 35 45 1 2 3 2 1 Pre-selected value: =30 kJ E Pre-selected value: =1 mm tFlyer Pre-selected value: =3 mm ginitial Pre-selected value: =-2 mm xflyer 0.5 1.0 1.5 2.0 0.5 1.5 2.5 3.5 -3

  • 1

1 3 Capacitor charging energy in kJ E Flyer thickness in mm tFlyer Initial gap width between flyer and target in mm ginitial x-position of the flyer edge in mm xflyer 1.5 3.0 4.5 Weld width wweld in mm Joint resistance R in µΩ Transferable force F in kN

Reference value of a non-welded (clamped) connection

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Numerical modelling

Experiment Corresponding macroscopic simulations

V109: 30kJ, 544kA, 22.2kHz, tflyer=2, gap=3, x=-2

Flyer: AW1050A H14/24 Target: Cu-DHP R240

V109: 30kJ, 544kA, 22.2kHz, tflyer=2, gap=3, x=-2

12 20 15 12 0.5 Target (EN AW-1050) Coil conductor (CuCrZr) Flyer (Cu-DHP) Flyer: AW1050A H14/24 Support Flyer (Cu-DHP) Target (EN AW-1050) Coil conductor (CuCrZr) Support

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Numerical calculation of collision parameters

12 20 15 12 0.5 Target (EN AW-1050) Coil conductor (CuCrZr) Flyer (Cu-DHP) Support Flyer (Cu-DHP) Target (EN AW-1050) Coil conductor (CuCrZr) Support

2 4 6 8 10 12 14

100 200 300 400 500 Distance to flyer edge d in mm Target Flyer vimpact Coordinate d d=0 α α α αimpact Impacting velocity vimpact in m/s 2 4 6 8 10 20 30 40 50 Impacting angle αimpact in Process parameters Capacitor charging energy: 30 kJ Initial gap flyer / target: 3mm Flyer Material: Cu-DHP Thickness: 1 mm Edge position: -2 mm Target Material: EN AW-1050 Thickness: 2 mm Edge position: 14 mm Distance to flyer edge d in mm

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Correlation of adjustable process parameters and collision parameters

Collision parameters at a distance of 2 mm from the flyer edge are considered because typically this area is welded if welding occurs at all.

20 40 60 Impacting angle αimpact tflyer in mm xflyer in mm ginitial in mm E in kJ 5 25 35 45 0 2 1 1.5 0.5 15 0.5 3.5 2.5 1.5

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1 2 3 80 200 400 600 800 Impacting velocity vimpact

Pre-selected value: E=20 kJ Pre-selected value: tflyer =1 mm Pre-selected value: ginitial =2 mm Pre-selected value: xflyer =0 mm Target

α

vimpact

2 mm

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SLIDE 16

Correlation of collision parameters and joint quality

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200 300 400 500 2 4 6 1.5 1.0 Pre-selected value: vimpact=400 m/s Pre-selected value: αimpact=15 10 20 30 Impacting velocity vimpact in m/s Impacting angle in mm αimpact 40 3 2 1 0.5 Transferable Force F in kN Resistance R in µΩ Weld width wweld in mm

Maximum transferable force in a lap shear test is considered for mechanical joint characterisation

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Summary

  • JOIN’EM aims at reducing the heavy use of copper to reduce cost and weight.
  • Hybrid aluminium copper parts shall replace current full copper solutions.
  • MPW is a promising technology for manufacturing copper aluminium joints.
  • An experimental and numerical process analysis considering MPW of

aluminium copper joints has shown that high quality joints require by trend

  • high impacting velocity (i.e. >250 m/s for welding of Cu-DHP and EN AW-1050) and
  • low impacting angle (i.e. 5°-20° for welding of Cu-DHP and EN AW-1050).
  • The impacting velocity is higher if
  • high capacitor charging energy (and consequently higher force) is applied and
  • the flyer thickness (and consequently the flyer mass to be accelerated) is low.
  • The impacting angle is lower if
  • the initial gap width between flyer and target is small and
  • the overlap of flyer and tool is relatively long.

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SLIDE 18

Acknowledgement

The JOIN’EM project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement

  • No. 677660.

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