What is Resistance Welding?
Complete guide based on AWS and RWMA standards
Resistance Welding (RW) is a metal joining process that uses heat generated by electrical resistance and mechanical pressure. Heat is produced by passing electrical current through the workpieces being joined, concentrating at the contact point where resistance is highest. This process is fundamental in the automotive industry, appliances, and metal manufacturing.
Types of Resistance Welding
Spot Welding
Most common process. Two electrodes apply pressure and current at specific points, creating a weld "nugget". Used in automotive bodies, metal cabinets, and appliances.
Seam Welding
Continuous variant of spot welding. Disc-shaped electrodes rotate while applying current, creating a hermetic weld line. Ideal for fuel tanks, radiators, and pressurized containers.
Projection Welding
Projections (protrusions) on one workpiece concentrate current at specific points. Used to weld nuts, studs, and fastening components to sheet metal.
Electrical Contact Welding
Electrodes with tungsten or molybdenum inserts for welding copper terminals, silver contacts, braided wire, and electrical components. Industrial applications in contactors, circuit breakers, and switches.
Key Factors in Resistance Welding
Electrode electrical and thermal conductivity determines how heat is transferred. According to AWS J1.3, RWMA coppers are classified from 1 to 4 by increasing hardness and decreasing conductivity. ALCAVIL manufactures electrodes per these specifications.
Applied pressure affects contact resistance and nugget shape. Too much force reduces resistance; too little causes material expulsion.
Modern MFDC (Mid-Frequency DC) controls allow shorter cycles and better control than traditional AC systems, reducing electrode wear.
The cooling system (chiller) must deliver a minimum of 1.5 GPM per electrode. Poor cooling accelerates wear and causes sticking.
Why AWS J1.3?
AWS J1.3 (Specification for Materials Used in Resistance Welding Electrodes and Dies) is the American Welding Society standard that defines minimum properties of materials for resistance welding electrodes. All ALCAVIL technical information is backed by this standard, ensuring real data, not marketing claims.
Need help selecting the right electrode?
Our engineering team can advise you on material selection for your specific application.