A bell-mouthed kerf is generally caused by

A bell-mouthed kerf is generally caused by

• A. Too much acetylene pressure
• B. Too much oxygen pressure
• C. An oxidizing flame
• D. A carburizing flame

Answer: (B)

Bell-mouthed kerf shows when the flame is too oxidizing, which happens when oxygen pressure is too high relative to the fuel. That excess oxygen makes the metal near the surface burn more aggressively as the cut begins, causing the kerf to widen outward at the top and form a bell-like shape. The fix is to reduce the oxygen pressure to bring the flame back into proper balance with the acetylene, and keep a steady torch height and feed so the cut progresses with a uniform kerf.

Bell-mouthed kerf shows when the flame is too oxidizing, which happens when oxygen pressure is too high relative to the fuel. That excess oxygen makes the metal near the surface burn more aggressively as the cut begins, causing the kerf to widen outward at the top and form a bell-like shape. The fix is to reduce the oxygen pressure to bring the flame back into proper balance with the acetylene, and keep a steady torch height and feed so the cut progresses with a uniform kerf.