[TheForge] scrap plate steel

[Gladish Family]

Is there a way to straighten steel plate?

I need to extend a welding table, so went to the local supplier and priced a
new 4x5, 1/2". For new steel it's ninety-some cents a pound, about $350...
But wait! There's a four by five chunk of 1/2" out back! About $100.
Unfortunately it must have had something sitting on it, because it's dished,
oh, maybe 3/8. Not that much, but the point is to have a dead flat surface
to do layout.
If it weren't so thick, I'd just build the frame and plug weld it, force it
to be straight, but 1/2" seems too burly.
Thanks for any suggestions,
Andy g.