Weldability

1
Weldability
2
Spot weldability

• Lesson Objectives
• When you finish this lesson you will understand
• Concept of Spot Weldability
• Electrode arrangements

• Learning Activities
• View Slides
• Read Notes,
• Listen to lecture
• Do on-line workbook

Keywords Current Level, Current Range, Lobe
Curve, Electrode Life, Peel Test, Nugget Size,
Button Size, Interfacial Failure, Shunting
Effect, Multiple Direct Electrodes, Series
Electrodes, Electrode Tooling
3
Process Characteristics as a Measure of
Weldability

• Current Level
• Current Range Weldability Lobe
• Process Deterioration
• Characterization of the loss in weld size at
  constant welding conditions
• Characterization of the variation in process
  requirements for maintaining welds of an adequate
  quality

Peel Test Used As Measure
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(No Transcript)
5
Button Size as a Measure of Weld Quality
Button Diameter
6
Modes of Failure in Spot Welds
Full Button Irregular Button
Interfacial Failure
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8
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9
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10
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11
Process Characteristics as a Measure of
Weldability

• Current Level
• Current Range Weldability Lobe
• Process Deterioration
• Characterization of the loss in weld size at
  constant welding conditions
• Characterization of the variation in process
  requirements for maintaining welds of an adequate
  quality

Peel Test Used As Measure
12
Nugget Diameter vs. Weld Current
Expulsion
Acceptable Nuggets
Nugget Diameter
Minimum Nugget Diameter
Small Nuggets
Weld Current
Nominal Current
13
(No Transcript)
14
Process Characteristics as a Measure of
Weldability

• Current Level
• Current Range Weldability Lobe
• Process Deterioration
• Characterization of the loss in weld size at
  constant welding conditions
• Characterization of the variation in process
  requirements for maintaining welds of an adequate
  quality

Peel Test Used As Measure
15
Current Range Weldability Lobe
Expulsion
Acceptable Nuggets
Nugget Diameter
Minimum Nugget Diameter
Time A
Small Nuggets
Weld Current
Lobe Curve
Time A
Weld Time
Smaller Brittle Nuggets
Expulsion Level
Acceptable Nuggets
Weld Current
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Questions
19
Process Characteristics as a Measure of
Weldability

• Current Level
• Current Range Weldability Lobe
• Process Deterioration
• Characterization of the loss in weld size at
  constant welding conditions
• Characterization of the variation in process
  requirements for maintaining welds of an adequate
  quality

Peel Test Used As Measure
20
Process Deterioration
Minimum Acceptable Diameter
Weld Diameter
Number of Welds
21
Shunting Effect
IB
IA
A
B
Itotal IA IB IARA IBRB IB/Itotal 1 -
RB/(RA RB)
Reference Resistance Welding Manual, p.1-7,
RWMA
22
Multiple Direct Electrodes
Series Electrode
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Tooling for Multiple Welding
Welding Pressure Adjustment Screw
Stud and Jam Nuts
Equalizing Bar
Compression Spring
Split and Clamped to Electrode
Flexible Conductors
Flexible Conductors
Slip-Fit
Slip-Fit
Workpiece
Lower Electrode
(a) (b)
Reference Resistance Welding Manual, p.17-8,
RWMA
24
Questions