current control

Dear,

What you see the metal is nothing but a magnet core. Having high magnetism, & requires low magnetising power. This is measured by inductance L. Higher the value of L, better will be the current limit action.

If you remove the metal magnet, all left is just a coil with an air medium. This shall require very high ( beyond the rating of welding m/c ) theoritically, & current limit operation will not be possible in practical terms. As inductance L value vwill be very low.