Fatigue Strength and Fatigue Crack Initiation and Propagation of High Strength Steels.

Strength gradient enhances fatigue resistance of steels

Steels are heavily used in infrastructure and the transportation industry, and enhancing their fatigue resistance is a major challenge in materials engineering. In this study, by introducing a gradient microstructure into 304 austenitic steel, which is one of the most widely used types of stainless steel, we show that a strength gradient substantially enhances the fatigue life of the material. ...

High-Strength Bainitic Steels

With careful design, mixed microstructures consisting of fine plates of upper bainitic ferrite separated by thin films of stable retained austenite have exhibited impressive combinations of strength and toughness in highsilicon bainitic steels. The silicon suppresses the precipitation of brittle cementite leading to an improvement in toughness. The essential principles governing the optimisatio...

High Temperature Fatigue Crack Propagation in INCONEL718

Observations on the Stress-corrosion Crack Propagation Characteristics of High-strength Steels

The relationahip between streas-corroslon crftck velocity and cracktip stress intensity is discussed. In most high-strength steels there is a wide range of stress intensity over which crack velocity is essentially constant. Methods of estimating this velocity are described. Values for a variety of high-strength steels are presented and the effects of metallurgical variables are indicated. Impli...

Side Effects of Shot Peening on Fatigue Crack Initiation Life

Shot peening beneficial effects on fatigue life of mechanical components are well known. However, there are some reports in the literature that indicate inappropriate shot peening parameters tend to reduce the fatigue life. It is therefore, the purpose of this study to find a logical quantitative justification for these observations. Using finite element method, a dynamic elastic-plastic simula...