Can the extreme heat from powder coating influence frame integrity of older bikes? I just got an older frame powder coated.  The shop that I took it to doesn't specialize in bikes.  They mainly do industrial grade powder coating and perhaps a car wheel here and there, so I wouldn't consider them the most knowledgeable people when it comes to handling frames.  The frame is lugged steel.  Could the heating process influence the frame's integrity?
No, 400F will not affect frame integrity.