Spot welding classification Within welding process families, is a spot weld considered a form of resistance welding (using electrode pressure and current to form a localized weld nugget)?

Difficulty: Easy

Correct Answer: Correct

Explanation:


Introduction / Context:
Processes are grouped so designers can choose appropriate methods for materials, thickness, and production rate. Spot welding is widely used in sheet-metal fabrication, notably in automotive body assemblies. Understanding its process family helps with symbol selection, equipment choice, and quality control.



Given Data / Assumptions:

  • Spot welds are small, discrete welds created at electrode contact points.
  • A power source delivers high current for a short time under electrode pressure.
  • No filler metal is assumed in typical resistance spot welding.


Concept / Approach:
Resistance welding processes (spot, seam, projection) generate heat by I^2 * R at the faying interface while clamp force consolidates the molten region into a nugget. Spot welding fits this definition precisely, distinguishing it from fusion processes such as gas metal arc welding, gas tungsten arc welding, or oxy-fuel welding which rely on an arc or flame and typically filler wire.



Step-by-Step Solution:

Place copper alloy electrodes on opposite sides of overlapped sheets.Apply force to ensure intimate contact at the faying surfaces.Pass a controlled high current for a set time to form a molten nugget.Hold force during solidification to complete the spot weld.


Verification / Alternative check:
Check process charts: if the primary heat source is electrical resistance with electrode pressure, the classification is resistance welding; spot welding clearly satisfies this.



Why Other Options Are Wrong:
Material-specific claims or cooling requirements do not define the process family. Shielding gas is not intrinsic to resistance spot welding.



Common Pitfalls:
Confusing spot welds with plug welds (holes filled by arc processes) and assuming visible weld beads define the process.



Final Answer:
Correct

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