Fatigue-Proof and Stressproof steel bars are melted as a modification of AISI 1144 steel. Fatigue-Proof is made by various combinations of mechanical working and thermal treatments including LaSalle’s e.t.d. (elevated-temperature drawing) process. Similarly, Stressproof is made by a process that consists of drawing the bar though a special die under heavy draft, then stress relieving it in a precisely controlled furnace. This datasheet provides information on composition, hardness, and tensile properties as well as fatigue. It also includes information on forming and machining. Filing Code: CS-31. Producer or source: Niagara LaSalle. Originally published November 1969, revised June 1989, revised June 2006.