A keyhole shaped opening in the root of a butt weld indicates both pieces are melting and there is proper penetration.

A keyhole shaped opening in the root of a butt weld indicates both pieces are melting and there is proper penetration.

• A. True
• B. False
• C. Not Applicable
• D. Sometimes

Answer: (A)

Key idea: a keyhole at the root means the arc is melting metal from both sides and maintaining an opening that allows fusion through the thickness. When you see a keyhole-shaped opening in the root of a butt weld, it shows the molten metal from each piece is being drawn into that opening and the weld is penetrating all the way through the joint. That pattern indicates proper penetration because the root is fused from one side to the other, not just surfaces on one side. So, the statement is true: the presence of a keyhole-shaped root opening is evidence that both pieces are melting and the weld has achieved proper penetration. If the keyhole weren’t present, penetration could be shallow or incomplete, depending on process and settings.

Key idea: a keyhole at the root means the arc is melting metal from both sides and maintaining an opening that allows fusion through the thickness. When you see a keyhole-shaped opening in the root of a butt weld, it shows the molten metal from each piece is being drawn into that opening and the weld is penetrating all the way through the joint. That pattern indicates proper penetration because the root is fused from one side to the other, not just surfaces on one side. So, the statement is true: the presence of a keyhole-shaped root opening is evidence that both pieces are melting and the weld has achieved proper penetration. If the keyhole weren’t present, penetration could be shallow or incomplete, depending on process and settings.