| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 829745 | Materials & Design (1980-2015) | 2014 | 6 Pages |
•Low-cost automotive wheel-disc steel and wheel-rim steel are designed, respectively.•Microstructures and mechanical properties under two cooling processes are studied.•F–P steel acts lower strength but higher ductility and toughness than F–B steel.•F–P and F–B meet demand of wheel-disc and wheel-rim applications, respectively.•Designed steels are commercially available for reducing the automotive wheel weight.
For the purpose of developing Nb–V–Ti microalloyed, hot rolled, high strength automotive steel for usage in heavy-duty truck wheel-discs and wheel-rims, appropriate cooling processes were designed, and microstructures and comprehensive mechanical properties (tension, bending, hole-expansion, and Charpy impact) of the tested steels at two cooling schedules were studied. The results indicate that the steel consists of 90% 5 μm polygonal ferrite and 10% pearlite when subjected to a cooling rate of 13 °C/s and a coiling temperature of 650 °C. The yield strength, tensile strength, and hole-expansion ratio are 570 MPa, 615 MPa, and 95%, respectively, which meet the requirements of the wheel-disc application. The steel consists of 20% 3 μm polygonal ferrite and 80% bainite (granular bainite and a small amount of acicular ferrite) when subjected to a cooling rate of 30 °C/s and a coiling temperature of 430 °C. The yield strength, tensile strength, and hole-expansion ratio are 600 MPa, 655 MPa, and 66%, respectively, which meet the requirements of the wheel-rim application. Both the ferrite–pearlite steel and ferrite–bainite steel possess excellent bendability and Charpy impact property. The precipitation behavior and dislocation pattern are characterized and discussed.
