Brings back memories of working in a heat treating facility in my youth. My part of the shop ran carb pots, and everything was 1500 to 1950 degrees F. One day as i walked through another part of the shop, a guy asked me to help him pick up a heavy shaft he had been straightening. I saw it was not glowing red or white, which to my world meant it was cool. So without thinking I picked it up bare handed. It was 500 F. That was the worse burn I ever suffered.
A roundabout way of saying, 500F is used to soften steel.