What is crater cracking, and how can you prevent it at the end of a weld?

What is crater cracking, and how can you prevent it at the end of a weld?

• A. Crater cracking occurs at the end of a weld as the crater cools; prevent by finishing with a crater fill or a short ramp and gradually stopping.
• B. Crater cracking occurs in the middle of the weld due to high current.
• C. Crater cracking is the same as porosity.
• D. Crater cracking can be prevented by stopping abruptly.

Answer: (C)

Crater cracking happens at the end of a weld in the crater where the last molten metal solidifies. As the weld cools and contracts, tensile stresses can form and a crack can grow from that crater into the weld if the end isn’t managed properly. The way to prevent it is to finish with a crater fill, or use a short ramp-down where you gradually reduce current and slow the travel so the crater closes smoothly instead of stopping abruptly. This helps relieve the stresses and avoids leaving a sharp, highly stressed end. You also want to keep shielding intact and control heat input to avoid rapid cooling that can promote cracking. The other statements aren’t correct because crater cracking isn’t something that occurs in the middle of the weld due to high current, it’s not the same as porosity, and stopping abruptly is more likely to cause—rather than prevent—crater cracking.

Crater cracking happens at the end of a weld in the crater where the last molten metal solidifies. As the weld cools and contracts, tensile stresses can form and a crack can grow from that crater into the weld if the end isn’t managed properly. The way to prevent it is to finish with a crater fill, or use a short ramp-down where you gradually reduce current and slow the travel so the crater closes smoothly instead of stopping abruptly. This helps relieve the stresses and avoids leaving a sharp, highly stressed end. You also want to keep shielding intact and control heat input to avoid rapid cooling that can promote cracking. The other statements aren’t correct because crater cracking isn’t something that occurs in the middle of the weld due to high current, it’s not the same as porosity, and stopping abruptly is more likely to cause—rather than prevent—crater cracking.