I have witnessed the use of heat on the hub, followed up with quenching the screw with dry ice. This method causes extreme expansion and contraction of the parts, creating a gap between the stuck parts, allowing them to be separated. Don't worry if you can't keep the dry ice from getting on both parts. You are only looking to cause expansion and contraction to break the bond (not make one part smaller than the other).
Carl

1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission