Transcript Butt Joint with Backing - Utah Valley University

Weld Types – Butt Joint with Backing
Butt Joint with Backing
 A Butt Joint with
Backing is the
basis for many
automotive
structural
sectioning welds.
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Butt Joint With Backing Example
Rail ready for welding.
Right and left rail section
with plug holes and center
insert.
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Butt Weld with Backing
 You should now have an understanding
of what a butt joint weld is and where it
is used.
 The next step is to tune the welder and
perform a butt weld that will be
evaluated visually and destructively.
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Butt Joint with Backing
 Joins two pieces of
closely butted
metal with a
backing piece.
 Requires a Root
gap of 3 metal
thicknesses.
 Too small of a root
gap will limit
penetration.
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Fit Up and Clamping
 Root Gap
 Two Top Pieces
 Backing is out of
the same metal
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Butt Joint with Backing
1” to 1.5”
Root Gap 3x metal thickness
 Set two coupons
on top of the
backing
 Set the proper root
gap
 Mark 1” to 1.5” in
the center
 Secure coupons for
weld
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Gun Position
90
90
 The proper gun to
work piece for a
butt joint with
backing is 90
degrees to the
surface.
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Tune the Welder
 Make sure to “Tune the Welder” by
making practice welds on the same
material that will be used for the final
weld.
 Make the necessary voltage and wire
speed adjustments and check for proper
penetration before beginning the final
weld.
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Lab Assignment
 Print off the Butt Weld “Task
Performance Sheet”.
 Set up and tune the welder.
 Set up and mark the coupons for the
weld.
 Perform the Butt with Backing Weld.
 Visually inspect the weld.
 Destructively test the weld.
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Visual Inspection
Length = 1” to 1.5”
Melt Through = 1/16” max.
Bead width = 3/16” to 3/8”
Check for penetration on back of
coupons
Height = 0” to 1/8”
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Using I-Car’s WQT Gauge
 I-Car has provided
a gauge to help in
visually inspecting
welds for:
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bead length
width
height
penetration
defects
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Using gauge to check:
Bead length
Bead Height
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Gauge also checks:
Weld Penetration
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Record The Results
 After the visual inspection is complete
record the results on the task
performance sheet and have the
instructor verify your results.
 Now the destructive test will need to be
performed.
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Destructive Weld Test
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Bend the top pieces toward each other.
Clamp in Vise.
Chisel off backing piece.
There should be continuous fusion on all
three pieces.
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Destructive Test
Notice the torn section – This is a sign of a
good weld
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Final Weld
 When the welds pass the visual and
destructive test observe the final voltage
and wire speed setting.
 Record the destructive test results on
the task performance sheet.
 Complete your final weld series in the
flat vertical and overhead position.
 Turn these in for grading.
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References
 Miller Electric Mfg. Co. Education.
http://www.millerwelds.com/education/library.html,
2006.
 Lincoln Electric Co. Lincoln Welders.
http://www.lincolnelectric.com/, 2006.
 Inter Industry Conference on Automotive Collision
Repair. I-CAR Online Training. http://www.i-car.com/,
2006.
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