Experimental Study of Heat Induced Deformation

Thermal stresses are frequently used to camber steel beams or repair damage caused by plastic deformation. A local concentration of heat is applied to part of the structure. The heated steel expands, but expansion is restricted by the surrounding unheated metal or other restraint. Large compressive stress develops and the steel yields, causing permanent deformations. This process is widely used and is known as flame cambering or heat straightening, but the process is not well understood by structural engineers. This paper describes a study which attempts to improve the scientific understanding of the method. It includes a brief historical review and a summary of the effects of elevated temperature on the material properties. An experimental program is then described. The parameters which have the greatest influence on the process are noted, and guidelines for using the method are provided.