| Abstract |
| This study aims at evaluating fatigue properties of two high strength steels, i.e., a V-and Cr containing alloy steel and a 0.84%C steel, used for automotive diaphragm spring. Fatigue properties were investigated on microstructure and strength under the fixed hardness condition. The fatigue limits of the two steels were same when tensile strengths were nearly same (over 1400 MPa), and that they were linearly decreased in the alloy steel austenitized and tempered at higher temperatuies. These results were then interpreted based on microstructural parameters such as prior austenite grain size, amount of carbides and twinnings, and martensite lath width. The alloy steel having the higher tensile strength and the smalles amount of carbides showed better fatigue properties than the 0,84%C steel. Thus, the fatigue properties of the spring steels can be pre-estimated by tensile strength instead of hardness since tensile strength correlated well with the fatigue limit. |
|
|
| Key Words |
| Diaphragm spring, Fatigue, Fatigue Limit, Carbide, Hardness |
|
|
 |
|
