Certified Welder Heat Input and Distortion Control 2 — Questions and Answers
Question 1: Which welding technique deposits short weld segments in the opposite direction of the overall welding progression?
- Skip welding
- Backstep welding (Correct answer)
- Balanced welding
- Cascade welding
Correct answer: Backstep welding
Backstep welding deposits each short segment in a direction opposite to the overall joint progression, distributing heat more evenly and reducing shrinkage distortion.
Question 2: Pre-setting (presetting) as a distortion control technique involves:
- Applying post-weld heat to straighten parts
- Positioning parts at an offset angle to compensate for expected distortion (Correct answer)
- Welding passes in a specific alternating sequence
- Peening the weld between passes
Correct answer: Positioning parts at an offset angle to compensate for expected distortion
Pre-setting positions the workpieces at an angle opposite to the expected distortion so that after welding and cooling, the parts return to the desired final position.
Question 3: How does peening a weld bead between passes help control distortion?
- It increases the cooling rate of the weld
- It stretches the weld metal to counteract contraction stresses (Correct answer)
- It adds filler metal volume to the joint
- It increases the hardness of the weld deposit
Correct answer: It stretches the weld metal to counteract contraction stresses
Peening mechanically stretches the weld metal, opposing the contraction that drives distortion, though it should never be applied to the root or final cap pass.
Question 4: Which distortion control method physically prevents movement by holding parts rigidly during welding?
- Balanced welding sequence
- Backstep welding
- Restraint and fixturing (Correct answer)
- Skip welding
Correct answer: Restraint and fixturing
Restraint and fixturing use clamps and jigs to hold parts in place during welding, physically resisting the shrinkage forces that would otherwise cause distortion.
Question 5: Alternating weld passes on both sides of a joint to equalize shrinkage forces is known as:
- Backstep welding
- Skip welding
- Balanced welding (Correct answer)
- Cascade welding
Correct answer: Balanced welding
Balanced welding alternates passes symmetrically on both sides of the joint so that shrinkage forces cancel each other out, minimizing angular and longitudinal distortion.
Question 6: Which type of distortion is caused by unequal transverse shrinkage through the thickness of a weld joint?
- Longitudinal shrinkage
- Angular distortion (Correct answer)
- Transverse bowing
- Buckling
Correct answer: Angular distortion
Angular distortion occurs when transverse shrinkage is greater at the face of the weld than at the root (or vice versa), rotating the plates about the weld axis.
Question 7: Compared to a few large passes, using more smaller passes in a multi-pass weld generally:
- Produces more total distortion due to repeated heating
- Reduces distortion by limiting peak temperature and heat input per pass (Correct answer)
- Has no effect on the total distortion
- Increases the HAZ size on each pass
Correct answer: Reduces distortion by limiting peak temperature and heat input per pass
More, smaller passes keep heat input per pass low, reducing peak temperatures and thermal gradients, which results in less cumulative distortion than fewer high-heat passes.
Certified Welder Heat Input and Distortion Control 2
Which welding technique deposits short weld segments in the opposite direction of the overall welding progression?