By doing so, weld current and force is focused into the small area of the projection, and heat is obtained from the resistance to the flow of the welding current. Due to this heat, the projections collapse and the parts are weld together. Another successful welding technique is capacitor discharge stud welding, which uses weld studs or specially formed bolts for welding instead of projections.
The definition of inert is slow or having no action or power to move. An example of inert is a slug that is standing still. having inertia; without power to move, act, or resist. tending to be physically or mentally inactive; dull; slow.
Both are filled with an inert gas. An inert gas is a gas that is generally non-reactive with other substances. The term inert means non-reactive. We refer to gases as being chemically inert if their atoms don't combine with other atoms in chemical reactions. If you are unfamiliar with the term 'inert,' it may make more sense with the following analogy.