In the given circuit switch is closed. In steady state the current will be :

6 A

In Steady state the inductor is short circuited hence no potential difference across inductor.

In this situation all the three resistors are in parallel.

$\Rightarrow R_{eq} = \frac{R}{3} = 3\Omega$ $\Rightarrow I = \frac{\xi}{3} = \frac{18}{3} = 6A$