End view of all three pieces.

I annealed two pieces by heating them to dull red. One I cooled in air, the other I dropped into water. I then rolled all three of them through my hand rollers, and at each step down I checked if there was any cracking. 

The un-annealed piece cracked badly at 3.8 mm.

The water quenched piece cracked at the sides and ends at 3.0 mm.

The air cooled piece didn't crack at all, down to 2.6 mm, but my sixth sense told me to stop.

Side view of the 2 annealed pieces.