Shouldn't be an issue, metal tubers surrounding the motor never cause problems. I still would suggest going with aluminum though. A bit lighter, and if you get good grade aluminum like 6061, very strong, and a lot easier to work with than steel.
I will be going with aluminum eventually, I just wanna get this damn thing going. And I am not just doing a simple plate, it is going to stabilize the sides of the chassis and double as a mounting plate for my ESC. So bends are involved.