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The current study proposes to approach the fatigue behavior of stabilizer bars and specimens manufactured in quenched / tempered and as-received SAE5160 steels with and without a surface micro-notch. Some S-N specimens and stabilizer bars were shot-peened to improve the fatigue strength due to creation of compressive surface residue stresses and by surface plastic strain and others samples received a surface micro-notch of 0.3 mm depth introduced by EDM process. The crack growth evaluation at micro-notch was made comparatively with da/dN-ΔK curves in CT specimens. The proposed experimental study consists of comparative analysis of da/dN-ΔK and S-N curves, fractographic and, metallographic analysis, stabilizer bar bench tests, and after that, it is intended to show the relevant aspects of two microstructural classes currently specified for stabilizer bars, the beneficial effects obtained by shot peening and the bad influences of surface micro-notches.

The present work gives an overview of the current situation of failures that may occur in automotive components, showing their distribution in the vehicle and the causes that make them occur, trying to emphasize the different materials which are used in the manufacturing of these components. This work is a technical approach strictly supported by an engineering concept which aims to discuss the different factors which contribute to cause premature failures of automotive components, prior to their utilization in the field or when they are exposed to the most variable conditions of use. One of the most important objectives of this study is to call the attention of design engineers, research engineers and manufacturing people to the importance of the components integrity which shall be taken into primary consideration in the design phase as well as in the specification of the material and process of manufacturing.