Certified Welder Base Metal Preparation 2

Question 1

When preparing stainless steel for welding, which cleaning agent should be avoided to prevent contamination?

Accepted Answer

Chlorinated solvents

Answer

Chlorinated solvents can leave residues that cause porosity and stress corrosion cracking in stainless steel welds.

Question 2

What is the primary purpose of beveling the edges of thick base metal before welding?

Accepted Answer

To ensure full penetration and fusion

Answer

Beveling creates a groove joint geometry that allows the weld to achieve full fusion and penetration through the entire joint thickness.

Question 3

Which condition on a base metal surface will most directly cause hydrogen-induced cracking in the weld?

Accepted Answer

Moisture or water

Answer

Moisture introduces hydrogen into the weld pool, and hydrogen diffusing into the heat-affected zone can cause delayed cracking.

Question 4

For a butt joint in ¾-inch carbon steel plate, a double-V groove is preferred over a single-V groove primarily because:

Accepted Answer

It reduces total weld metal required and distortion

Answer

A double-V groove requires less filler metal than a single-V and distributes weld shrinkage on both sides, reducing angular distortion.

Question 5

A welder notices blue-gray discoloration on the surface of carbon steel plate. This most likely indicates:

Accepted Answer

Heat tinting from prior thermal cutting

Answer

Blue-gray oxidation is characteristic of heat tinting that occurs when steel is exposed to elevated temperatures during flame or plasma cutting.

Certified Welder Practice Test