Question

which shielding gas is the best choice for using spray transfer on carbon steel base metal?

argon + 2% to 5% oxygen
75% argon + 25% co2
80% argon + 20% co2
100% co2

Explanation:

Locate the target parameters in the reference table

Using the Spray Transfer Requirements and GMAW Shielding Gas Effects knowledge points

We need to find the best shielding gas for spray transfer on carbon steel base metal.
Looking at the reference table under the "Carbon Steel" section:

• Locate the column labeled "Spray Transfer".
• The table legend indicates:
• \(R =\) Required
• \(C =\) Capable
• \(NR =\) Not Recommended

Evaluate the options against the table data

Using the GMAW Shielding Gas Effects knowledge point

Let's check the rating for each of the given multiple-choice options under the "Spray Transfer" column for "Carbon Steel":

• Argon + 1% to 5% Oxygen: Rated as R (Required / Recommended / Best choice).
• 75% Argon + 25% CO2: Rated as NR (Not Recommended).
• 80% Argon + 20% CO2: Rated as C (Capable).
• 100% CO2: Rated as NR (Not Recommended).

Therefore, Argon + 1% to 5% Oxygen is the best choice (rated R).

Answer:

• (A) Argon + 2% to 5% Oxygen (Correct answer)
• (B) 75% Argon + 25% CO2
• (C) 80% Argon + 20% CO2
• (D) 100% CO2