The spot welding process is used for joining sheet materials through heat and pressure.  Heat turns the metal into a molten pool which will be contained by the pressure applied by the electrode tip.  

• Spot welding is one of a group of resistance welding processes that involve the joining of two or more metal parts together in a localized area by the application of heat and pressure.
• High quality welds can also be made in stainless steels, nickel alloys, aluminum alloys and titanium for aerospace application.
• High strength steels, coated steels and aluminum alloys are of great interest to the automotive industry but can have weldability problems.
• Ultrasonic non-destructive testing has been proved and widely applied at vehicle manufacturers but still requires skill and training to achieve high accuracy.
• Spot welding offers a number of advantages over other techniques, including high speed, ease of automation and energy efficiency.
• There are some limitations on material weldability but attention to correct setting up and good process control can solve most production problems.

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