AWS AWS Weld Metallurgy & Heat Treatment 2 — Questions and Answers
Question 1: Heat input in welding is calculated using which formula?
- (Voltage × Amperage) / Travel Speed
- (Amperage × Travel Speed) / Voltage
- (Voltage × Amperage × 60) / Travel Speed (Correct answer)
- Amperage × Time × Resistance
Correct answer: (Voltage × Amperage × 60) / Travel Speed
Heat input (J/in) is calculated as (Voltage × Amperage × 60) / Travel Speed in inches per minute.
Question 2: Increasing travel speed in welding generally:
- Increases heat input and widens the HAZ
- Decreases heat input and narrows the HAZ (Correct answer)
- Has no effect on heat input
- Increases penetration but decreases bead width
Correct answer: Decreases heat input and narrows the HAZ
Faster travel speed reduces heat input per unit length, resulting in a narrower HAZ and less distortion.
Question 3: Weld distortion is primarily caused by:
- Incorrect filler metal selection
- Uneven heating and cooling creating differential thermal expansion and contraction (Correct answer)
- Using too low a welding current
- Inadequate shielding gas coverage
Correct answer: Uneven heating and cooling creating differential thermal expansion and contraction
Distortion results from uneven expansion during heating and contraction during cooling, which creates internal stresses that deform the workpiece.
Question 4: Backstep welding is a technique used to:
- Repair defective welds
- Reduce distortion by controlling the sequence of weld deposits (Correct answer)
- Increase penetration in thick materials
- Improve welder efficiency
Correct answer: Reduce distortion by controlling the sequence of weld deposits
Backstep welding involves making short weld segments in a direction opposite to the overall progress, which helps distribute heat more evenly and reduce distortion.
Question 5: Peening a weld bead is done to:
- Test for weld soundness
- Introduce compressive stresses to counteract tensile shrinkage stresses (Correct answer)
- Improve the surface appearance of the weld
- Remove slag inclusions
Correct answer: Introduce compressive stresses to counteract tensile shrinkage stresses
Peening plastically deforms the weld bead, introducing compressive stresses that help offset the tensile residual stresses caused by weld shrinkage.
Question 6: Which welding sequence is MOST effective for minimizing angular distortion in a butt weld?
- Completing all passes on one side before welding the other side
- Using a balanced welding sequence, alternating passes on each side (Correct answer)
- Welding all passes in one direction only
- Using the highest possible heat input
Correct answer: Using a balanced welding sequence, alternating passes on each side
Balanced welding, alternating passes between both sides of the joint, distributes shrinkage forces symmetrically and minimizes angular distortion.
AWS AWS Weld Metallurgy & Heat Treatment 2
Heat input in welding is calculated using which formula?