Researchers at the University of Toledo, Toledo, OH, recently compared the fatigue performance forged steel, cast iron, and cast aluminum steering knuckles. The study is drawing a lot of attention in the automotive industry because it shows:
- Yield strength of forged steel to be 140% higher than cast aluminum and 85% higher than cast iron
- Ductility of forged steel to be 270% higher than cast aluminum and 48% higher than cast iron
- Fatigue strength (at 106 cycles) of forged steel to be 190% higher than cast aluminum and 40% higher than cast iron
- Forged steel to be superior with respect to cyclic plastic deformation--a major concern for automotive suspension components\
- Forged steel knuckles to give about 100 times longer fatigue life than cast aluminum knuckles at the same stress level.
The study was conducted by Dr. Ali Fatemi and Research Assistant Mehrdad Zoroufi with funding by the Forging Industry Educational & Research Foundation (FIERF) in cooperation with the American Iron and Steel Institute.
Research Assistant Mehrdad Zoroufi, left, and Dr. Ali Fatemi check their laboratory setup at the University of Toledo for comparative fatigue testing of steering knuckles.
The researchers will discuss results of their study at the Great Designs in Steel Seminar on February 18 in Livonia, MI, at the SAE 2004 World Congress March 8-11 in Detroit, and at the Forging Industry Technical Conference April 19-21 in Detroit.