PowerShell - replace is not working with variable

I want to get word from sam5.txt file and remove that from test.txt BUT even though the variable $SD is taking correct value, it is not replaced with bank in test.txt

Experts help is most appreciated.

-----------------------------------------------------------------------------------------------------------------------script start-------------------

$SD = GC "C:\Users\hdelwadiaadmin\sam5.txt"
echo $SD
(Get-Content "\\192.168.0.203\it\IT\PROJECT\AD-Users-Info-Update\test.txt") -replace '$SD' , ' ' | Set-Content "\\192.168.0.203\it\IT\PROJECT\AD-Users-Info-Update\test.txt"

------------------------------------------------------------------------------------------script ends-----------------------------------------------

Regards,

HirenDel