Which statement about ERW is true?

Which statement about ERW is true?

• A. One principle is that there is no external heat source, filler metal, or flux; any desired properties must be provided by the material being welded
• B. ERW requires filler metal for all welds
• C. ERW uses external heat sources to provide heat
• D. ERW cannot join dissimilar metals

Answer: (A)

ERW relies on electric resistance heating of the metal itself, with the edges welded together under pressure, and no filler metal or flux is added. Because there’s no external heat source and no filler to contribute alloying elements, the weld’s properties come entirely from the base material and the welding parameters (current, pressure, speed, edge preparation). In other words, the weld is formed by fusing the metal that you start with, so any desired strength, hardness, or corrosion resistance must be provided by choosing the right base material and controlling the process—there’s nothing to tailor with additional welding consumables. While ERW can sometimes join different metals, the defining point is that it does not rely on filler or external heat to shape the weld, which makes the statement true.

ERW relies on electric resistance heating of the metal itself, with the edges welded together under pressure, and no filler metal or flux is added. Because there’s no external heat source and no filler to contribute alloying elements, the weld’s properties come entirely from the base material and the welding parameters (current, pressure, speed, edge preparation). In other words, the weld is formed by fusing the metal that you start with, so any desired strength, hardness, or corrosion resistance must be provided by choosing the right base material and controlling the process—there’s nothing to tailor with additional welding consumables. While ERW can sometimes join different metals, the defining point is that it does not rely on filler or external heat to shape the weld, which makes the statement true.