Download - Shear-Strength Data
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Inspection and Testing
Radiography
[Drawbacks]
The time element in
developing the negative and
obtaining the necessary
information
Impracticability of taking the
welded parts to the X-ray
machine with the attendant
time element involved
Not all faults are revealed
Interpretation of radiographs
requires a highly skilled
technician
Peel Test Shown in the figure:
Visual Inspection
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Peel Test and Chisel Test
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Button Size as a Measure of
Weld Quality
Button
Diameter
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Modes of Failure in Spot Welds
Full Button Irregular Button
Interfacial Failure
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Long Life Test
-- on 1.3-mm Thick 6009-T4 Arc Cleaned/Conversion-Coated Sheet
with Truncated Cone Electrodes and Current Stepping
Percent
Heat(%)
Button
D
iameter(mm)
Undersized
Buttons/Strip
Number of Welds
[Reference: SAE
840291, Patrick,
Auhl, and Sun]
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Shear-Strength Data for Long
Life Test
-- on 6009-T4 Arc Cleaned/Conversion-Coated Sheet
Number of Welds
ShearStrength(kN/S
pot)
[Reference: SAE 840291,
Patrick, Auhl, and Sun]
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Minimum Tensile-Shear Strength
of Spot Welds in Aluminum Alloys
[Reference: Resistance Welding Manual, p.11-26, RWMA]
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Resistance Spot Weld
Radiographs 1 mm Sheet
[Reference: Joining of Aluminum Alloys 6009/6010, Hoch]
6009/6009 5182/5182 2036/2036
Small
Cracking
Large Center
Porosity
Large
Cracking
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Types of Defects Revealed by Radiography
Undersize nugget
Inadequate diameter
Inadequate penetration
Oversize nugget
Excessive diameter
Excessive penetration
Odd and misshapen nuggets
Extent of Alclad inclusion
into the nugget
Extrusion of the nugget
Cracking of the nugget
Porosity
Expulsion from faying
surfaces
Segregation of eutectic in
parent material
Electrode pickup Size or extent or granular
zone
Nugget penetration
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Setup Procedures and Suggested Schedules [Step 1] Insert electrode of
proper size and tip contour
for the gauge combination.
Align electrodes.
[Step 2] Set pressure gage
for suggested welding force,and check with an electrode
force gauge.
[Step 3] Adjust the control
to provide the approximate
suggested weld and
postheat time.
[Step 4] The welding
currents shown are
approximate and intended to
be a guide. The magnitude of
the welding current is usually
controlled by a heat dial orphase-shift control.
[Step 5] Check the machine
for consistency of operation
by making and testing twentysingle spot tension-shear
specimens and five
macroscopic examination
specimens.
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Typical Oscillograph Record during
Welding
Voltage
Force
Forge ForceWelding Force
Displacement
Current
1 V
1 kN
0.25 mm
5.0 kA rms
0.1 sec
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Typical Oscillograph Record
Current
Force
Displacement
Voltage
5.2 kA RMS
0.7 kN
0.2 mm
1.0 V (p-t-p)
Zero line
for force
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Resistance Spot Weld Data
[Reference: Guidelines
to Resistance SpotWelding Aluminum
Automotive Sheet,
p.9, The Aluminum
Association]
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Shunting Effect on 2024-T
AlcladFactors Influencing
Shunting
Effect Include: Thickness and
resistance of the alloy
being welded
Shunting effect
increases as the stock
thickness and
resistance decrease
Surface resistance of[Reference: Resistance Welding Manual, p.11-19, RWMA]
ShuntPathResistance,
Microohms
JointStrength,
lb/we
ld
Weld Spacing, in.
JointStrengthShuntResistance
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Suggested Minimum Weld Spacing
Edge and Flange Distance
[Reference: Resistance Welding Manual, p.11-20, RWMA]