developments and applications of numerical simulation in ......projection welding of srew nuts...

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Developments and applications of numerical simulation in resistance welding

Greitmann, Martin; Nielsen, Chris Valentin; Zhang, Wenqi

Publication date:2013

Link back to DTU Orbit

Citation (APA):Greitmann, M. (Author), Nielsen, C. V. (Author), & Zhang, W. (Author). (2013). Developments and applications ofnumerical simulation in resistance welding. Sound/Visual production (digital)

https://orbit.dtu.dk/en/publications/af9db217-110a-4f90-a331-7ed182051c7c

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1IIW Essen 2013, C-III©2013 M. J. Greitmann, Hochschule Esslingen

Martin GreitmannHochschule Esslingen University of Applied SciencesGermany

Chris V. Nielsen and Wenqi ZhangSWANTEC Software and Engineering ApSDenmark

Developments and Applications of Numerical Simulation in

Resistance Welding

IIW-Doc. III-1680-13


Resistance spot welding (material: DC04; t1=0.8mm / t2=1.5 mm)

Quality assurance numerical process analysis

Spotwelder (1997)

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Numerical Simulationresistance welding

SYSWELD ® (FRAMASOFT S.A./FRAMATOME)

SPOTSIM ® (RWTH Aachen, Tula State University)

SPOTWELDER ® (MPA Stuttgart)

SORPAS ® (SWANTEC Software and Engineering ApS)

Software:


Resistance WeldingMODEL FOR NUMERICAL ANALYSIS

Geometry Material data ( Young’s modulus, µ, ... )

Electrode force

Structure mechanicModel

Stress distribution

Deformation

Temperature-

fieldDesign

Welding current Material data ( cp, Rk,, ... )

Electric-thermalModel

Temperature distribution

Numerical process analysis

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Mechanical Model - Machine



Data base

physical material properties

electrical resistivity thermal conductivity heat capacity cp


4


Data basemechanical material properties



Database

Material Resistance

and Contact Resistance

20

40

60

80

100

120

140

µ

180

Ele

ctric

al R

esis

tanc

e

0 400 800 1200 °C 2000

Temperature

RAlloy ( t1 = t2 = 1.25 mm; AlMg0.4Si1.2 )RContact Resistanc ( Model: MPA Stuttgart )RAlloy + RContact Resistanc

Temperature

Co

nta

ct

Re

sis

tan

ce


5


Measurement - transition resistance

ISO 18594


0 1 2 3 4 5 6 7 8

CuFe2P, t = 0,6 mmCuFe2P, t = 0,4 mmCuFe2P, t = 0,2 mm

CuNi3Si1Mg, t = 0,6 mmCuNi3Si1Mg, t = 0,4 mmCuNi3Si1Mg, t = 0,2 mm

CuNiCo1Si, t = 0,4 mmCuNiCo1Si, t = 0,2 mm

CuSn8, t = 0,6 mmCuSn8, t = 0,4 mmCuSn8, t = 0,2 mm

CuZn37, t = 0,6 mmCuZn37, t = 0,4 mmCuZn37, t = 0,2 mmE-Cu58, t = 0,6 mmE-Cu58, t = 0,4 mmE-Cu58, t = 0,2 mm

CuCrAgFeTiSi, t = 0,4 mmCuCrAgFeTiSi, t = 0,2 mm

Übergangswiderstand / m

Transition resistance (copper alloys)

(MPA Stuttgart)Transition resistance

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Numerical process analysisHot staking process

Resistance welding of commutator segments with hook geometry



Resistance welding of commutator segments

slot geometry hook geometry

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1984 R. Schwab (doctoral thesis): Numerical simulation of Hot Staking process

commutator segments with slot geometry

temperature field temperature-time-curve

(Schweißen und Schneiden, 38 (1986), Heft 8, S. 365-369)


Numerical process analysisHot staking process (2012)

(Lanier)


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Numerical process analysisHot staking process (2012)

(Lanier)



Numerical process analysiselectrotecnic application

wire termination

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W-Elektrode

W-Elektrode

CuSn6 -Gabel

CuL -Draht

Numerical process analysiselectrotechnic application

FEM Model & Process

(Dötzer)



(Dötzer)

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19IIW Essen 2013, C-III©2013 M. J. Greitmann, Hochschule Esslingen Projection Welding - Joint Geometry

Stress distribution(von Mises)


Projection welding



Calculated projection deformation and temperature distribution

(Kußmaul, Blind, Zeng, Greitmann, Schäfer, 1991)

Database: Temperature-dependent stress-strain behaviour of the used projection

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calculated movement and temperature distribution


(Vichniakov, Herold, Greitmann, Roos, 2002 in Mathematical modelling of the weld phenomena )

2001 Alexei Vichniakov (doctoral thesis): numerical simulation of projection welding


(Bschorr, Cramer, SLV München NL der GSI mbH)

Numerical process analysisprojection welding of srew nuts

Projection welding: srew nuts onto high strength steel sheet

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(Bschorr, Cramer, SLV München NL der GSI mbH)

Numerical process analysisprojection welding of srew nuts

Optimization of srew nut geometry

old new


• Square nut welding

Numerical process analysisprojection welding

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circular saw

stellite hard facing

1920 1960

Brazing (CuAg solder)

resistance welding Laser beam welding

1985 1992

band saw(grinded)

padsaw

padsaw

Numerical process analysisCarbide tipped saw blade


FE-Model (geometry)

FE-Model

ElektrodeTrägersegment

HartmetallElektrodenbacken

Experimental setup

Numerical process analysisCarbide tipped band saw

(Greitmann, Wink)

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Current distribution

A

A

Temperature field

time: 70 ms

Videoclip


(Greitmann, Wink)


Carbide tipped saw band

Hartmetall

Sägeband


(Greitmann, Wink)

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Längsschnitt

Realtime-Bildfolgezeit

5 ms

Konturabstand 100 °C

Temperatur-bereich

0°C bis 2000 °C

nach 70 msVideoclip


(Greitmann, Wink)


APPLICATION

Spot Welding

Numerical process analysisresistance spot welding

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Numerical process analysisresistance spot welding (1996)


Example: Variable sheet thickness


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100

200

300

400

µ

600

Res

ista

nce

0 10 20 30 40 50 60 ms 80

Time

Pickle: 12% NaOH/60°C/60s Pickle: 12% NaOH/60°C/60s; cleanednatural SurfacePickle: 25% NaOH/65°C/60s; cleanedbrushed surface

Alloy: AlMg0.4Si1.2; ( t = 1.25 mm )

Spot welding Aluminium


(Greitmann, Kessler, 1990)


Aluminium sheets with variable surface conditions (contact resistance)


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Temperature distribution


(Greitmann, Wink)


local temperature–time history

0

200

400

600

800

1000

1200

1400

1600

1800

0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0

Time

Tem

per

atu

re

Position 1 Position 2






Position 13

Sheet material: DX54D+Z100 Sheet thickness: 1,0 mmElektrode material: CuCrZrDome radius: 40 mmElektrode force: 2,5 kNWelding current: 8 kACurrent-flow time: 240 ms

s

°C

current flow time


(Greitmann, Wink)

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Spot welding 3-sheets



Microstructure and hardness distribution

Spot welding 1.5 mm DP600 steel sheets

Measured micro hardness comparing to simulated hardness near the weld nugget

Macrograph of real weld comparing to simulated weld nugget and martensite distribution


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Weldability Lobe Welding process window

Welding current

Fo

rce

Minimum weld size

Acceptable

weld size

Expulsion

Zone

TypicalNugget failures

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Weld process optimization

Undersizedweld

Acceptable

weld size

Expulsion

Zone

Sorpas®

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Weld Schedule Specifications with optimal welding parameters

Weld PlanningWeld Schedule Specification

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Spot welding – Electrode misalignmet

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43

Projection welding Longitudinal embossment

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Square nut projection welding

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3D simulation of weld strength testing

• Tensile shear test of weld strength after welding

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• Tensile shear test of weld strength with SORPAS® 3D

Tensile shear weld strength test curve simulated by SORPAS® 3D

Tensile shear weld strength curve in ISO 14273:2000.

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• Cross tension test of weld strength after welding

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• Cross tension test of spot weld strength

Cross tension weld strength test curve simulated by SORPAS® 3D

Cross tension weld strength curve in ISO 14272:2000.

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Resistance WeldingNumerical Simulation

• Process simulation – Weldability of materials, weld nugget sizes

– Electrode geometry and coatings

• Process optimisation – Weld growth curves

– Weldability lobes - welding process windows

• Process planning – Optimal welding process parameters

• Weld quality and properties after welding– Microstructures and hardness

– Weld strengths and fracture modes

• Welding with adhesives– Fluid adhesives

– Solid polymer or plastics

developments and applications of numerical simulation in ......projection welding of srew nuts...

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