What is crater cracking in TIG welding and how can it be prevented?

• A. Crater cracking happens in the middle of a weld due to excessive shielding gas.
• B. Crater cracking occurs at the end of a weld due to rapid cooling and high thermal stress; prevent by filling the crater, finishing with a small filler tail, or using a cold-start/finish technique and proper travel speed.
• C. Crater cracking is a porosity issue caused by moisture in filler wire.
• D. Crater cracking is only a cosmetic surface defect and does not affect joint strength.

Answer: (B)