Resistance Welding — What It Is and Why It Matters
Resistance welding is a family of welding processes that generate heat through electrical resistance at the interface between two overlapping metal pieces clamped under pressure. No filler metal or shielding gas is required — the weld is formed entirely by the combination of heat and pressure.
The main resistance welding variants include spot welding (RSW), seam welding (RSEW), projection welding, and flash welding. All share the same principle: electrical resistance at the workpiece interface generates localized heat, and applied force consolidates the joint.
Resistance welding dominates high-volume manufacturing — automotive, appliance, and electronics industries rely on it for fast, repeatable, automatable joints. Cycle times measured in fractions of a second and no consumables (other than electrode tip dressing) make it the most cost-effective joining method for sheet metal assemblies at production volumes.
Frequently Asked Questions
What metals can be resistance welded?
Most common metals can be resistance welded, with low-carbon and galvanized steel being the easiest. Stainless steel and aluminum require higher current and more precise parameter control. Copper and brass are difficult because their high conductivity makes it hard to concentrate heat at the joint.
Why is resistance welding used in car factories?
Speed, consistency, and automation. A robotic spot welder can make a weld in under a second with repeatable quality. No filler metal or gas means no consumables cost per joint. A single car body requires thousands of spot welds, making this process essential for automotive production volumes.