Less heat is required to preheat a surface for piercing than is needed to start on an edge.

Less heat is required to preheat a surface for piercing than is needed to start on an edge.

• A. True
• B. False
• C. It depends on material
• D. Heat is never less

Answer: (B)

The idea being tested is how heat input differs between preheating a surface for piercing and starting a weld on an edge. Preheating aims to raise the workpiece to a specific, relatively high temperature across the area to be welded. That usually requires a substantial and sustained amount of heat input to bring and hold the metal at that target temperature, especially for thicker sections or tougher steels. Starting a weld on an edge, on the other hand, benefits from the geometry: the arc can be established at the edge and the molten metal can anchor and propagate with less overall preheat energy. Because of that, more heat is typically needed to preheat for piercing than to start on an edge. So the statement is false.

The idea being tested is how heat input differs between preheating a surface for piercing and starting a weld on an edge. Preheating aims to raise the workpiece to a specific, relatively high temperature across the area to be welded. That usually requires a substantial and sustained amount of heat input to bring and hold the metal at that target temperature, especially for thicker sections or tougher steels. Starting a weld on an edge, on the other hand, benefits from the geometry: the arc can be established at the edge and the molten metal can anchor and propagate with less overall preheat energy. Because of that, more heat is typically needed to preheat for piercing than to start on an edge. So the statement is false.