Magnetic Pulse Welding

8/17/2019 Magnetic Pulse Welding

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MAGNETIC PULSE

WELDING


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INTRODUCTION

• MPW is a modern day state of theart “o!d "e!din#$ %roess or more%reise!y a “so!id state "e!din#$

%roess ha&in# ana!o#y to E'%!osi&e"e!din# (E)W* +

• E)W ta,es he!% of ener#y d-e to the

detonation of e'%!osi&es to a-se theim%at of the "or,%iees+ The-nder!yin# %rini%!es of E)W and MPWare the same+


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• .o"e&er/ MPW is more !ean and%reise o%eration d-e to the -se ofe!etroma#neti dri&in# fores+

• It is one of the &ariants of im%at"e!din# tehno!o#ies "herein"e!din# of t"o simi!ar or dissimi!ar

materia!s o-r &ia hi#h0s%eedim%at of the meta!s +


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• MPW an a!so 2e termed as a sho,"e!din# %roess "here the -rrent %-!se%assin# thro-#h the e!etroma#neti oi!

s-rro-ndin# the "or,%iees %rod-e theneessary hi#h0%ress-re to attain as-essf-! "e!d+

• The MPW %roess is free form theemissions !i,e f-me/ s%atter/ heat that arety%ia!!y %rod-ed d-rin# the on&entiona!"e!din# tehni3-es+


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Working Principle

• In MPW/ a tremendo-s amo-nt ofener#y is om%ressed and dishar#edin an e'treme!y short %eriod of time+

• The 2asi %rini%!e is sho"n in the4#-re 2e!o"+

• The "or, %iees are %!aed inside a

oi!+ A !ar#e amo-nt of ener#y isom%ressed and dishar#ed in ane'treme!y short %eriod of time+


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• Some systems an dishar#e -% to

than 5 mi!!ions am%s in on!y 677miroseonds+

• The hi#h ener#y 8o"s in the oi!/ and

the dishar#e of e!etri ener#yind-es the so0a!!ed 9eddy -rrents9in the e'terna! "or, %iee+

•

:oth -rrents (in the oi! and in thee'terna! "or, %iee* ind-e ma#neti4e!ds/ "hih o%%ose eah other+


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• The reation fores 2et"een theo%%osin# ma#neti 4e!ds are forin#the e'terna! %art to"ards the interna!%art at hi#h &e!oity to a-se

"e!din#+• The im%atin# s%eed is more than

6777 ,m;h+

• This res-!ts in a %ermanentdistortion/ "itho-t s%rin#02a, of the"or,%iee+


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• The at-a! %roess !asts no !on#er then 677miroseonds+

• No %rotetin# atmos%here/ 4!!er materia!s or

other aidin# materia!s are neessary+• The ma#neti %-!se "e!din# %roess is a

9o!d9 "e!din# %roess/ the materia! does not#et "armer than eted ?one is reated/and the meta! is not de#raded+ The "e!d2eomes the stron#est %art of the assem2!y+


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MPW Parameters

• Discharge energy

• Stored ener#y in the a%aitor 2an, isdishar#ed into the oi! and this ener#y is

res%onsi2!e for the mo&ement of the 8yermeta!+

• Dishar#e ener#y ta,es %!ae in a &eryshort time in the ran#e of a fe"miroseonds in order to ae!erate the8yer meta! so that it im%ats the other %artat a hi#h &e!oity+


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• Inreasin# the har#in# &o!ta#e or thea%aitane of ondensers/ inreases the

dishar#e ener#y and th-s/ the shearin#stren#th of the "e!ds "i!! 2e enhaned +

• In fat/ there is a thresho!d &a!-e of thedishar#e ener#y to %rod-e the "e!d+

• .o"e&er/ the orret ener#y m-st 2e -sed toa&oid e'eedin# ritia! strain rate of themateria! that an tear them+

• It means that for eah materia! om2ination

there is a minim-m of ener#y neessary to @oin 2oth materia!s/ and there is a ma'im-mof ener#y 2efore tearin# or ra,s to the"e!din# %roess+


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• Standof Distance

The stando> distane is the distane2et"een %arts %rior to the dishar#e+

• This #a% m-st e'ist at eah "e!din#/2ea-se/ "hen ma#neti %ress-re is done

on the 8yer meta!/ it m-st ha&e s%ae to#ain &e!oity and a3-ire ,ineti ener#y thatis #oin# to 2e transformed into im%atener#y+

• In order to ha&e #ood "e!din# 2et"een 2othmeta!s/ there is an o%tim-m &a!-e ofstando> distane/ "hih &aries aordin# to

the "e!din# materia!s+


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• When stando> distane de&iates from that&a!-e/ the &e!oity and the ,ineti ener#yred-es/ !eadin# to a red-tion in theshearin# stren#th and the "idth of the "e!d

• If the stando> distane is !o"/ o!!ision ta,es

%!ae 2efore the 8yer meta! o-!d reah thema'im-m &e!oity+

• On the other hand/ for hi#her stando>distane/ the &e!oity dro%s to a !o"er &a!-e

at the time of o!!ision+• In terms of dishar#e ener#y/ the hi#her the

#a%/ the hi#her sho-!d 2e the dishar#eener#y in order to o2tain a #ood 3-a!ity "e!d +


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• Magnetic Pressure

Ma#neti %ress-re is one of the %arametersres%onsi2!e for dri&in# the 8yer meta! into the%arent meta!+

• D-e to the ind-ed Eddy C-rrent/ the ma#neti%ress-re "i!! o%%ose the ma#neti 4e!d from the oi!

and fore the 8yer meta! to #ain &e!oity -nti!o!!ision+

• In order to ha&e a s-essf-! 2ond/ the ma#neti%ress-re m-st 2e hi#h/ other"ise the 8yer meta! "i!!

rash into the %arent meta! "ith !o"er &e!oity andno 2ondin# "i!! o-r+

• .i#h ma#neti %ress-re an 2e o2tained "ith hi#hdishar#e ener#y or hi#h fre3-eny -rrent+


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• Impact Velocity

• The im%at &e!oity is in8-ened 2y the ener#yand the stando> distane+

• In ma#neti %-!se "e!din# the im%at %ress-re is&ery hi#h and onse3-ent!y/ the im%at &e!oity isa!so &ery hi#h/ a-sin# %!asti deformation at the

interfae 2et"een %arts to "e!d+

• The "e!din# re3-ires that 2oth s-rfaes that are#oin# to 2e @oined sho-!d 2e free ofontamination/ and th-s/ the hi#h &e!oity of the

8yer meta! %!ays an im%ortant ro!e/ 2ea-se it "i!!reate a @et that "i!! remo&e any ontaminants oro'idation %arti!es from 2oth ontat s-rfaes


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• The im%at &e!oity is diret!y

orre!ated "ith the ener#y anddishar#e time from the a%aitor/thro-#h the oi! into the 8yer meta!+

•

If the ener#y is transferred at !o"&e!oity/ the 8yer "or, %iee "i!!o!!a%se and no 2ondin# is %rod-ed+


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What MPW Can Weld

•

A!-min-m to a!-min-m+• A!-min-m to o%%er+

• A!-min-m to ma#nesi-m+

• A!-min-m to titani-m+

• Co%%er to o%%er+

• Co%%er to stee!+

• Co%%er to 2rass+

• Ni,e! to titani-m+• Ni,e! to ni,e!+

• Stee! to stee!+


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Advantages

• The "e!d is stron#er than the %arent materia! d-rin#

materia! testin# the ra, a%%ears o-tside the "e!d area+• A %rotetin# atmos%here/ 4!!er materia!s or other aid

materia!s are not neessary+

• Ma#neti %-!se "e!din# is a 9o!d9 "e!din# %roess/ the

%arts are not heated+ Therefore no heat a>eted ?one isreated/ and no !oss of materia! %ro%erties ta,es %!ae+

This a!so means that the "e!ded "or,%iees an 2e-n!am%ed immediate!y after "e!din# and an 2e f-rther%roessed immediate!y+

•

.i#h %rod-tion s%eed/ sometimes -% to 67 %iees %ermin-te+

• It is an eo!o#ia! "e!din# %roess/ sine no heat/radiation/ #as or "e!din# f-mes are %rod-ed+


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Limitations

• MPW is !imited to t-2-!ar #eometries and !a% @oints+

• :ea-se of the "ay the %roess "or,s/ it is not%ossi2!e to reate a 2-tt "e!d "ith MPW+

•

T-2-!ar is the easiest #eometry/ from 2oth theener#y ons-m%tion and oi! desi#n&ie"%oints+ As !on# as the t-2-!ar %art to 2emo&ed is !osed (for instane/ a retan#-!art-2e*/ a stron# eddy -rrent "i!! 2e #enerated2y the oi!+ A t-2e "ith a s!it in it "i!! not ha&ethe ond-ti&ity neessary and therefore "i!!not reat %ro%er!y+


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Applications Dissimi!ar meta! @oints

Aluminium-Stainlesssteel (c) : Pulsar Ltd

Aluminium to copper


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Parts from the a-tomoti&e ind-stry

MPW &sMIG;MAG "e!din# (aironditionin#%arts*


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B-e! 4!ters


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Dri&e a'is (a!-mini-m 0 stee! onnetion* and

%ress-re &esse! in an aironditionin# system


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Part from an e'ha-st system


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Referenes• Magnetic pulse elding: an e!cient and

environmentall" #riendl" multi-material $oining techni%ue (Angshuman &apil'Aha" Sharma' ) -

ournal o# Cleaner Production

• Magnetic pulse elding #or tuularapplications: *iscovering ne technolog"#or elding conductive materials+P - +, +./ 0 P1P 2.34AL5 MA3C,6777

.L8 69' 677 /8: /4-+;124 SP1+;'


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Magnetic Pulse Welding