Transition from small to long fatigue crack in C-Mn steel
- Dr. A.Q. Khan Research Labs., Rawalpindi (Pakistan). Metallurgy Div.
- Univ. of Sheffield (United Kingdom). Dept. of Mechanical and Process Engineering
Fracture mechanics is an effective mechanism for characterizing the fatigue crack propagation. Generally, fatigue crack growth rate (da/dN) is presented as a function of stress intensity range ([Delta]K). A conventional fatigue crack growth curve of da/dN versus [Delta]K can be divided into three regions, i.e. region 1 (near threshold), 2 (Paris) and 3 (fast) crack growth regions. Depending upon the region of crack growth, fatigue crack growth behavior can be sensitive to microstructure, environment and loading conditions. In the near threshold region, fatigue crack growth rates are very slow and the influencing of microstructure, environment and load ratio on the rates of crack propagation is very significant. In the Paris region, there is a linear relationship between log(da/dN) and log([Delta]K). In this region the crack growth properties are not so sensitive to microstructure and load ratio. In the fast crack propagation regime, the rate of crack growth is relatively sensitive to microstructure and load ratio. In the present study small fatigue crack behavior in the ferrite-bainite microstructure of C-Mn steel is investigated. The fatigue crack growth threshold is calculated with respect to barrier to crack growth and transition from microstructure sensitive (small crack) to microstructure insensitive (long crack) crack growth is estimated.
- OSTI ID:
- 5306130
- Journal Information:
- Scripta Metallurgica et Materialia; (United States), Journal Name: Scripta Metallurgica et Materialia; (United States) Vol. 30:1; ISSN 0956-716X; ISSN SCRMEX
- Country of Publication:
- United States
- Language:
- English
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