Which process is typically used to join a sheet metal part to a fastening device such as bolts or nuts?

Which process is typically used to join a sheet metal part to a fastening device such as bolts or nuts?

• A. Projection Welding
• B. Upset Welding
• C. Flash Welding
• D. Gas Welding

Answer: (A)

Projection welding uses small raised projections on the sheet or on the fastener to concentrate electric current and heat at the weld interface, creating a localized weld that securely attaches a sheet metal part to a bolt or nut. This resistance-welding method is fast, energy-efficient, and ideal for high-volume production because it delivers strong joints with controlled heat input without melting through the parts. Upset welding is typically used for joining ends of pieces by deforming them under pressure, not for attaching a separate fastener. Flash welding also creates welds through high current and deformation but is more suited to butt joints along longer interfaces rather than fastening a bolt or nut to sheet metal. Gas welding relies on flame heating and filler metal and lacks the speed and repeatability needed for attaching fasteners to sheet metal.

Projection welding uses small raised projections on the sheet or on the fastener to concentrate electric current and heat at the weld interface, creating a localized weld that securely attaches a sheet metal part to a bolt or nut. This resistance-welding method is fast, energy-efficient, and ideal for high-volume production because it delivers strong joints with controlled heat input without melting through the parts. Upset welding is typically used for joining ends of pieces by deforming them under pressure, not for attaching a separate fastener. Flash welding also creates welds through high current and deformation but is more suited to butt joints along longer interfaces rather than fastening a bolt or nut to sheet metal. Gas welding relies on flame heating and filler metal and lacks the speed and repeatability needed for attaching fasteners to sheet metal.