Stud Welding Technologies in Shipbuilding

Report
Copyright © Nelson Stud Welding, Inc.
Aluminum Stud Welding
Technologies
By Chris Hsu and Clark Champney
Nelson Stud Welding, Inc.
May 10-11, 2011
2011 AWS Conference and Exhibition Welding in Shipbuilding
1
Copyright © Nelson Stud Welding, Inc.
Challenges
 Low melting point
 High thermal
conductivity
 Tough oxide (3488F)
 Spatter
 Softening
May 10-11, 2011
2
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Drawn Arc Stud Welding 101
A.
Pilot
Arc
B.
C.
D.
Lift
Plunge Remove
Main Arc
Chuck
May 10-11, 2011
3
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Capacitor discharge
AWS Seattle May 10, 2011
4
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CD welding Process
 Weld time
 Timing tip
 Plunge speed
 Current
 Cap voltage
 Cable impedance
 Contact
 Gap
 Stored Arc
May 10-11, 2011
2011 AWS Conference and Exhibition Welding in Shipbuilding
5
Copyright © Nelson Stud Welding, Inc.
MIL specifications
 MIL-S-24149/2D:
aluminum stud and
ferrule for drawn arc
 MIL-S-24149/5C:
aluminum stud for
CD and stored arc
AWS Seattle May 10, 2011
6
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Gun accessories
 Gas foot
 Tranquil arc plunge
dampener
 Motorize gun
AWS Seattle May 10, 2011
7
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plate thickness to stud
diameter ratio
 Develop full strength
 Steel: 1/3
 Aluminum (Al is annealed in stud welding)
 ½ for drawn arc
 ¼ for CD
AWS Seattle May 10, 2011
8
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Weld strength: tensile/torque
AWS Seattle May 10, 2011
9
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Internally threaded studs
 Diameter ¼” to ½”
 Threads #10-24
thru ½-13
 5000 series alloy
used for stud
(Magnesium based)
 LNG tankers
AWS Seattle May 10, 2011
10
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Pulse cleaning and welding
 Cut oxide, rust, oil,
mill-scale
 Reduce heat input
 backside marking
 Stiffen arc
 Out of position
 Angle iron
 Aluminum
 Peak: cathodic clean
 Background: heat
May 10-11, 2011
Stud Welding Technologies – ShipTech 2011
11
Copyright © Nelson Stud Welding, Inc.
Process monitor & logger






Weld energy
Stud hang-up
Cold plunge
Cable overheat
Weld Pass / Fail
Production log
Normal
Cold
Hot
Hang-up
May 10-11, 2011
Welder, Gun and Cable
Stud Welding Technologies – ShipTech 2011
12
Copyright © Nelson Stud Welding, Inc.
Summary
 CD - contact, gap and stored arc
 Drawn arc
 Pulse
 AC
 Up to ½” can be welded down hand and plate vertical
 Inverter to weld 5/8” and ¾” in flat position
 Process monitor
 Drawn arc
 CD
May 10-11, 2011
2011 AWS Conference and Exhibition Welding in Shipbuilding
13

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