Dave Looman
Ansys Employee

Could you email me those images at dave.looman@ansys.com ?  They're hard to read in the forum.  I can't explain why solving in 2 or 3 steps would slow the heating.  The time integration might not be as accurate and if the loading is ramped it might be ramped over a longer time, but those two effects wouldn't make a huge difference.  A factor of 2 in the heating rate at most.