A welder is interpreting a weld symbol for a square-groove butt joint. The symbol shows a square-groove preparation and the number '5' on top of the reference line, followed by '300'. Below the reference line, a 6 mm fillet weld symbol is indicated. What does the '5' and '300' above the reference line signify?

Question: A welder is interpreting a weld symbol for a square-groove butt joint. The symbol shows a square-groove preparation and the number '5' on top of the reference line, followed by '300'. Below the reference line, a 6 mm fillet weld symbol is indicated. What does the '5' and '300' above the reference line signify?

Answer options:

• The root opening is 5 mm, and the weld length is 300 mm. ✅ The groove weld penetration is 5 mm, and the weld length is 300 mm.
• The weld size is 5 mm, and the pitch of the intermittent weld is 300 mm.
• The throat thickness is 5 mm, and the length of each weld segment is 300 mm.

Correct answer: The groove weld penetration is 5 mm, and the weld length is 300 mm.

Explanation: For a square-groove weld, the number placed directly on the weld symbol (above the reference line for the arrow side) indicates the required depth of penetration or effective throat thickness. The '300' after the length dimension for a continuous weld denotes the overall length; for an intermittent weld, it would be the pitch.