HEAT BALANCE
Heat Balance
Lesson Objectives
When you finish this lesson you will
understand:
• Factors Effecting Heat Balance
• Solve Heat Balance Problems
Learning Activities
1. View Slides;
2. Read Notes,
3. Listen to lecture
4. Do on-line
workbook
Keywords: Heat Generation, Heat Conductions, Electrode
Geometry, Resistivity, Thermal Conductivity
Factors Affecting Heat Balance
• Relative electrical and thermal conductivities of
the metals to be jointed
• Relative geometry of the parts at the joint
• Thermal and electrical conductivities of the
electrodes
• Geometry of the electrodes
Heat Balance in Projection Welds
Factors affecting uniform distribution of
heat are :
•
•
•
•
•
Projection design and location.
Thickness of the section.
Thermal and electrical conductivities.
Heating rate.
Electrode alloy.
Temperature Distribution
At the end of
welding time
After 20%
welding time
Workpiece
Electrode
Temperature
distribution at
various location
during projection
welding.
Temperature
Heat Dissipation
Water-Cooled Copper Alloy Electrode
Base Metal
Weld Nugget
Base Metal
Water-Cooled Copper Alloy Electrode
Improving Heat Balance Methods
for Spot Welding
(a)
(b)
Improving Heat Balance Methods
for Spot Welding
High Conductivity
Alloy
(a)
High Resistance
Electrode
Low Conductivity
Alloy
(b)
High Conductivity
Alloy
Low Conductivity
Alloy
(c)
(d)