AWS Distortion Control & Residual Stress Flashcards

What effect does increasing heat input have on distortion in a welded joint?

Answer: It generally increases distortion by expanding a larger volume of metal

Higher heat input heats a larger volume of base metal, resulting in greater thermal expansion, more weld metal deposited, and thus more distortion.

Which type of distortion in a long weld causes the workpiece to bow along its length (like a banana shape)?

Answer: Longitudinal bowing

Longitudinal bowing occurs when the weld metal shortens along the weld axis during cooling, bending the workpiece lengthwise.

Stress relief annealing of a weldment is typically performed at what approximate temperature range for carbon steel?

Answer: 1100°F–1200°F (593°C–649°C)

Stress relief of carbon steel weldments is typically performed at 1100°F–1200°F (593°C–649°C), held for one hour per inch of thickness.

Which welding parameter change most effectively reduces angular distortion in a single-V groove weld?

Answer: Using a double-V groove to balance heat on both sides

Converting to a double-V groove and alternating passes on both sides balances transverse shrinkage, effectively eliminating angular distortion.

What does 'vibratory stress relief (VSR)' use to reduce residual stresses in a weldment?

Answer: Mechanical vibrations at resonant frequency to redistribute residual stresses

VSR uses mechanical vibration at resonant frequencies to cause local plastic flow, reducing and redistributing residual welding stresses without heat.

In a T-joint fillet weld, 'longitudinal shrinkage' acts in which direction relative to the weld?

Answer: Parallel to the weld axis (along the length of the weld)

Longitudinal shrinkage acts parallel to the weld axis, shortening the weld length and causing bowing or bending along the joint.