Welding Techniques and Processes Flashcards

Which welding process is most commonly specified by vehicle manufacturers for structural collision repair?

Answer: Squeeze-type resistance spot welding (STRSW)

Squeeze-type resistance spot welding (STRSW) is the OEM-preferred process because it most closely replicates the factory spot welds used in vehicle assembly.

When performing MIG plug welds as a substitute for factory spot welds, what drill bit size is typically used to prepare the plug weld hole?

Answer: 8 mm (5/16 inch)

An 8 mm (5/16 inch) hole is the standard size for MIG plug welds to ensure adequate weld nugget size matching factory spot welds.

What is the primary reason oxyacetylene welding is generally prohibited on modern high-strength steel (HSS) structural components?

Answer: The heat-affected zone is too large and degrades HSS properties

Oxyacetylene welding creates an excessively large heat-affected zone that anneals and destroys the strength properties of high-strength steel.

In MIG (GMAW) welding for collision repair, which shielding gas mixture is most widely recommended?

Answer: 75% argon / 25% CO2

A 75% argon / 25% CO2 mixture provides the optimal balance of arc stability, penetration, and spatter control for automotive steel welding.

What does the term 'heat-affected zone' (HAZ) refer to in welding?

Answer: The region of base metal that was not melted but had its properties altered by welding heat

The HAZ is the area of base metal adjacent to the weld that was not melted but experienced temperatures high enough to change its microstructure and mechanical properties.

When welding ultra-high-strength steel (UHSS), why must weld wire selection match the base metal strength?

Answer: To ensure the weld joint meets or exceeds the base metal's tensile strength

Using weld wire matched to UHSS base metal strength ensures the completed joint meets the original design tensile requirements for structural integrity.

Which personal protective equipment (PPE) is specifically required to protect a welder's eyes from UV and IR radiation?

Answer: A welding helmet with the appropriate shade lens

A welding helmet with an appropriate shade number (typically shade 10–13 for MIG) is required to protect eyes from the intense UV and IR radiation produced by the welding arc.