Galvanized steel sheets have a zinc coating to prevent corrosion. The coating is effective as long as it’s not breached. Unfortunately, one of the most common methods of sheet metal assembly—resistance spot welding—does just that. Clinching, on the other hand, does not. 

Clinching produces a round, button-like connection between two to four layers of sheet metal. The process can join metal sheets of different thicknesses. It can join dissimilar materials, such aluminum and copper, without creating an isolating intermetallic phase. The process can even be used on stainless steel.