REMOVING TILT LATCHES

Sash are welded together at edges. The only visable way to remove tilt latch is on the top edge and tried removing with vise grips and would not budge. Are these sash mfg to be disposable sash when latches break?? Is there a replacement part for this??,if so i would need a right and a left.Please advise on what is avail. Would I be able to cut in a top mount latch if avail??

Thank you,
Rich