[TheForge] warped 1" plate table

[Peter Fels and Phoebe Palmer]

I'm in over my head again and wish to beg some of you-all's expertese.
This 1"x8'x9' plate is warped and while I've been able to 
herd  the  warpage around, I've been unable to get it flat.
It is up on house jacks in the work yard and presently has a gentle 
diagonal crease about 3' long  so the thing is high on 2 corners.
The theory I had was that by spot heating and quenching, it would shrink a 
little at that spot and that if a line was heated and quenched,it would 
shrink along  the length of that line.
What seems to be happening instead is that the spot heated area bulges and 
only partially returns to flat when quenched and that the heated line seems 
to  cause a folding  along the line that draws the sides up perpendicular 
to the heated line.
So the theory is wrong.
Would someone be so kind as to explain this  and how to control it and fix 
the problem..or where to find the info?....thanks...Pete F