The grating noise is caused by the windings of the voice coil rubbing
against the outside of the airgap (pole plate).

With due care you can check if the woofer is misaligned by softly moving the
cone.
Place four fingers at 90 degree intervals on an imaginary circle on the cone
and push gently so the cone moves perfectly straight. If the woofer is
well-centered, no grating should be heard. When you push with one finger
only the cone is tilted to that side. Then at some point the voice coil will
touch the pole plate and produce noise.

In your case what you'd find is that moving the cone without making noise
will actually require you to push it asymetrically. Trying at different
spots will tell you in what direction it is misaligned.

Apparently you weren't afraid to replace the surround once so I suggest you
remove it again and redo the job. With the surround removed, the cone
normally returns to its center position when the woofer is placed flat on
its back (can be checked with the above trick), so if you manage not to tilt
it while fixing the surround all should be fine.

Good luck,

Bruno