Which statement correctly contrasts oxy-fuel welding and arc welding in terms of heat source?

Which statement correctly contrasts oxy-fuel welding and arc welding in terms of heat source?

• A. Oxy-fuel uses a flame from burning gas for heating and cutting; arc welding uses an electric arc for welding.
• B. Oxy-fuel uses an electric arc for heating; arc welding uses a flame for welding.
• C. Oxy-fuel can weld structural steel as a sole method without preheating.
• D. Oxy-fuel uses a plasma jet for cutting; arc welding uses a torch flame.

Answer: (A)

The main idea is the source of heat in each process. Oxy-fuel welding uses a flame produced by burning fuel gas in oxygen to heat the metal (and can be used for cutting in some setups). Arc welding gets its heat from an electric arc created between an electrode and the workpiece, melting the metal to form a weld. This contrast—flame heat from combustion versus electric arc heat—is exactly what the correct statement conveys: oxy-fuel relies on a gas flame for heating and cutting, while arc welding relies on an electric arc for welding. The other options mix up the heat sources or add unrelated ideas (like plasma cutting). For example, saying arc welding uses a flame or that oxy-fuel can weld structural steel without preheating aren’t accurate descriptions of how the heat is produced in these processes.

The main idea is the source of heat in each process. Oxy-fuel welding uses a flame produced by burning fuel gas in oxygen to heat the metal (and can be used for cutting in some setups). Arc welding gets its heat from an electric arc created between an electrode and the workpiece, melting the metal to form a weld. This contrast—flame heat from combustion versus electric arc heat—is exactly what the correct statement conveys: oxy-fuel relies on a gas flame for heating and cutting, while arc welding relies on an electric arc for welding.

The other options mix up the heat sources or add unrelated ideas (like plasma cutting). For example, saying arc welding uses a flame or that oxy-fuel can weld structural steel without preheating aren’t accurate descriptions of how the heat is produced in these processes.