I was actually thinking of an actual heat wave akin to this aspect of wall of fire:
"One side of the wall, selected by you, sends forth waves of heat, dealing 2d4 points of fire damage to creatures within 10 feet and 1d4 points of fire damage to those past 10 feet but within 20 feet."
Atop that, add in the heat metal aspect for something like...
Heat Wave (Su): Once every x rounds, a dwarf crusher can emit a wave of volcanic heat. All creatures within x feet suffer xdx points of fire damage to creatures, while those x to x feet from the construct take xdx points of fire damage. All metal equipment carried by creatures within the area is also subject to a heat metal effect (caster level 12th, Will DC X negates). The save DC is Constitution-based.