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Welding in Shipbuilding May 10-11, 2011Seattle, Washington

Projection Welding: An Overview

Chonghua (Cindy) Jiang

AET Integration, Inc.

50388 Dennis Ct.Wio!, "I #83$3

Cindy.%iang&aet'int.co!


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Definition

“Projection welding is an electric resistance welding process that

produces welds by the heat obtained from the resistance to the flow

of the welding current. The resulting welds are localized at

predetermined points by projections, embossments, or intersections

!Welding "andboo#, $ol. %, Part &, p'()


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Typical Projection Designs

a. *mbossed b. +tudtoPlate c. -nnular


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*amples of Projection Design

*amples of $arious Projection Designs /efore and -fter Welding

!Welding "andboo#, $ol. %, Part &, p'0)


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*amples of -nnular Projections



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Typical 2ommercially -3ailable 4asteners 5sed

in Projection Welding



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7edium 4re8uency !74D2) 7achine

-2 7achine

2apacitor Discharge !2D) 7achine

Projection Welding *8uipment


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Projection Welding *8uipment !2ont9d)


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Welding in Shipbuilding May 10-11, 2011

Seattle, Washington

Design and location of the projection

Thic#ness of the sections

Thermal and electrical conducti3ity of the materials

"eating rate

*lectrode geometry and alloy Tooling alignment

Weld force

4actors -ffecting "eat /alance


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Seattle, Washington

Welding 2urrent Welding current must be at least high enough to create fusion before the

projection has completely collapsed

Weld Time Weld time is dependent on the welding current and projection rigidity

Depending on the type of base metal and its surface conditions, multiplepulses can be applied to yield the desired weld performance

*lectrodeDies Proper electrode design and alloy is a major factor in ma#ing projection

welds

*lectrode 4orce *lectrode force is critical for proper projection collapse without epulsion

and formation of a sound weld

;ey Process $ariables


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Seattle, Washington

4ormation of Projection Welds

-nnular Projection Weld

!solid state bonding de3elops)

*mbossed Projection Weld!fused nugget forms)


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Seattle, Washington


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Welding Trials on >.0 mm 7agnesium -?%>, -*T

7aterials +uitable for Projection Welding*ample


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Seattle, Washington

*ample of Project Weld Property

7icrohardness


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Parts preparation

Weld area clean of grease, rust, scale, dirt or shearing burrs


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Assue: Weld did not pass dye penetrant test and pull test

Boot 2auses: Tooling misalignment

Ansufficient forging force at the faying surface

-ctions Ta#en: 2hec# tooling misalignment by using carbon imprints between faying surfaces

Ancrease applied forging force

-djust welding parameters to get sufficient weld bonding area

Projection Weld Performance Ampro3ement:

Example 1

4racture surface =o /onding


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Example 2

Intergranu*ar +racture "ode o a -ro%ection We*d +ai*ed during er/ice


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Seattle, Washington

/ase 7etal/ase 7etal

"-? "-?

ro1en 2art ith Intergranu*ar +racture

4on'ro1en -art

The ro1en 2art ith I6 racture shos 2ri!ary errite a*ong grain oundary. This genera**y resu*ts in

*o ducti*ity and racture toughness. The ase !eta* !icrostructure o the ro1en 2art ith I6 racture is a resu*t o i!2ro2er heat treat!ent

o the ase !eta* eore it as e*ded.


Example 2 (Cont’d)


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Seattle, Washington

-d3antages

$ersatility

+peed

*ase of automation

-bility to ma#e multiple welds simultaneously


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Tuu*ar connections

Projection Welding -pplications


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Seattle, Washington

Projection Welding -pplications !2ont9d)


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-ttaching nuts and stud

+heet metal assemblies

Tan# fittings and ferrules

4usites

Projection Welding -pplications !2ont9d)


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S ttl W hi t

4abricate the metal sandwich plate of large area

Projection welding

-dhesi3e assisted projection welding

!+T+ +hipbuilding, +outh ;orea)

(Welding in the World , 3 '%, n C1, p '>>, &((6)

-ttach nuts and stud

Potential Projection Welding -pplications

for +hipbuilding

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