Which item is not typically a distortion-control method?

Which item is not typically a distortion-control method?

• A. Fixtures.
• B. Clamps.
• C. Preheating.
• D. Heat sinks.

Answer: (C)

Distortion comes from uneven heating and cooling, so distortion-control methods focus on restraining movement or managing heat input around the weld. Fixtures and clamps physically hold the workpieces in place, preventing movement that would lead to warping. Heat sinks pull heat away from the weld area, reducing the peak temperature and the heat-affected zone, which helps minimize distortion from differential cooling. Preheating raises the entire piece to a higher temperature before welding; while it can reduce cracking in some steels, it increases overall heat input and can widen heat gradients if not managed, making distortion control less direct. So, preheating is not typically considered a distortion-control method.

Distortion comes from uneven heating and cooling, so distortion-control methods focus on restraining movement or managing heat input around the weld. Fixtures and clamps physically hold the workpieces in place, preventing movement that would lead to warping. Heat sinks pull heat away from the weld area, reducing the peak temperature and the heat-affected zone, which helps minimize distortion from differential cooling. Preheating raises the entire piece to a higher temperature before welding; while it can reduce cracking in some steels, it increases overall heat input and can widen heat gradients if not managed, making distortion control less direct. So, preheating is not typically considered a distortion-control method.