What is burn-through?

What is burn-through?

• A. Melt-through of base metal from excessive heat or poor joint design.
• B. A decorative finish.
• C. A measurement of weld strength.
• D. A type of slag deposition.

Answer: (A)

Burn-through happens when the weld causes the base metal to melt completely through, creating a hole. This is usually the result of too much heat input or a joint design that allows excessive penetration, especially on thinner materials. In practice, if the heat is too high, the arc lingers too long in one area or the base metal can’t support the weld without puncturing through to the far side. That’s why this option—describing melt-through of the base metal caused by excessive heat or a poor joint design—best captures the mechanism and causes of burn-through. Decorative finishes, weld strength measurements, and slag deposition relate to other welding concerns and do not describe what burn-through is. To avoid burn-through, reduce heat input, adjust travel speed, or modify joint design and fit-up so the weld does not penetrate through the entire thickness of the base metal.

Burn-through happens when the weld causes the base metal to melt completely through, creating a hole. This is usually the result of too much heat input or a joint design that allows excessive penetration, especially on thinner materials. In practice, if the heat is too high, the arc lingers too long in one area or the base metal can’t support the weld without puncturing through to the far side. That’s why this option—describing melt-through of the base metal caused by excessive heat or a poor joint design—best captures the mechanism and causes of burn-through.

Decorative finishes, weld strength measurements, and slag deposition relate to other welding concerns and do not describe what burn-through is. To avoid burn-through, reduce heat input, adjust travel speed, or modify joint design and fit-up so the weld does not penetrate through the entire thickness of the base metal.