I-CAR Welding Techniques and Processes 2

Question 1

What is the correct sequence for performing a MIG plug weld on a structural panel?

Accepted Answer

Weld around the perimeter of the hole, then fill the center

Answer

Starting around the perimeter ensures fusion to the lower panel before filling the center, producing a consistent nugget that mimics a factory spot weld.

Question 2

When using STRSW equipment, what parameter most directly determines weld nugget size?

Accepted Answer

Electrode tip diameter

Answer

The diameter of the electrode tip directly governs the contact area and thus the diameter of the resistance spot weld nugget produced.

Question 3

What is a 'destructive weld test' used to verify in collision repair?

Accepted Answer

That the weld settings produce a weld nugget of adequate size and penetration on scrap metal

Answer

A destructive weld test on scrap material confirms that current settings produce welds with proper nugget size and fusion before the same settings are applied to the vehicle.

Question 4

Which type of weld joint is most commonly used when installing a sectioned structural rail?

Accepted Answer

Butt weld joint with backing

Answer

A butt weld with a backing strip or backing support is preferred for sectioning structural rails because it provides full penetration and strength equivalent to the original joint.

Question 5

Why must aluminum welding use a dedicated MIG welder or torch liner, separate from steel equipment?

Accepted Answer

Steel contamination from shared liners causes porosity and weld defects in aluminum

Answer

Steel particles left in a shared liner contaminate aluminum welds, causing porosity, inclusions, and dramatically weakened joints.

I-CAR - Inter-Industry Conference on Auto Collision Repair Certified Practice Test

I-CAR - Inter-Industry Conference on Auto Collision Repair Certified Practice Test

I-CAR Welding Techniques and Processes 2