Here's some information from the collision industry that explains that heat can be used to bend some structural steels such as Model A frames. It's interesting to note over heating (greater than 1200 degrees) will damage the metal properties.
http://www.i-car.com/pdf/fordfram.pdf
http://www.i-car.com/html_pages/tech...ml#Anchor-3800
http://genuinegmparts.com/pdf/techIn...ity_Matrix.pdf