Further application of the cleavage fracture stress model for estimating theT0of highly embrittled ferritic steels

2016 ◽  
Vol 107 (2) ◽  
pp. 123-132
Author(s):  
P. R. Sreenivasan
Keyword(s):  
Cleavage Fracture ◽  
Fracture Stress ◽  
Ferritic Steels ◽  
Stress Model ◽  
Cleavage Fracture Stress

On the Microstructural Basis of Cleavage Fracture Initiation in Ferritic and Bainitic Steels

1984 ◽  
Vol 106 (2) ◽  
pp. 173-177 ◽  
Author(s):  
T. Saario ◽  
K. Wallin ◽  
K. To¨rro¨nen
Keyword(s):  
Cleavage Fracture ◽  
Fracture Stress ◽  
Fracture Initiation ◽  
Ferritic Steels ◽  
Statistical Nature ◽  
Brittle Crack ◽  
Stress Criterion ◽  
Bainitic Steels ◽  
Bainitic Microstructure ◽  
Cleavage Fracture Stress

The microstructural basis of the critical tensile stress criterion of cleavage fracture is discussed. It is shown that cleavage can be carbide induced in bainitic steels as well as in ferritic steels. The plastic work expended in brittle crack propagation is shown to be somewhat smaller for bainitic steels than for ferritic steels. This is proposed to be caused by the much higher dislocation density of the bainitic microstructure. The statistical nature of the cleavage fracture initiation process is shown to result in a test piece geometry dependent cleavage fracture stress.

The Weibull Stress Model for Predicting Cleavage Fracture in the Ductile-to-Brittle Transition Region

2008 ◽  
Author(s):  
Xiaosheng Gao ◽  
Jason P. Petti ◽  
Robert H. Dodds
Keyword(s):  
Fracture Toughness ◽  
Transition Region ◽  
Cleavage Fracture ◽  
Model Parameters ◽  
Ferritic Steels ◽  
Stress Model ◽  
Brittle Transition ◽  
Ductile To Brittle Transition ◽  
Constraint Effects ◽  
Weibull Stress

Transgranular cleavage fracture in the ductile-to-brittle transition region of ferritic steels often leads to spectacular and catastrophic failures of engineering structures. Due to the strongly stochastic effects of metallurgical scale inhomogenieties together with the nonlinear mechanical response from plastic deformation, the measured fracture toughness data exhibit a large degree of scatter and a strong dependence on constraint. This has stimulated an increasing amount of research over the past two decades, among which the Weibull stress model originally proposed by the Beremin group has gained much popularity. This model is based on weakest link statistics and provides a framework to quantify the relationship between macro and microscale driving forces for cleavage fracture. It has been successfully applied to predict constraint effects on cleavage fracture and on the scatter of macroscopic fracture toughness values. This paper provides a brief review of the research conducted by the authors in recent years to extend the engineering applicability of the Weibull stress model to predict cleavage fracture in ferritic steels. These recent efforts have introduced a threshold value in the Weibull stress model, introduced more robust calibration methods for determination of model parameters, predicted experimentally observed constraint effects, demonstrated temperature and loading rate effects on the model parameters, and expanded the original Beremin model to include the effects of microcrack nucleation.

Effects of microstructure on cleavage fracture stress in steel

Metal Science ◽  
1978 ◽  
Vol 12 (11) ◽  
pp. 511-514 ◽  
Author(s):  
D. A. Curry ◽  
J. F. Knott
Keyword(s):  
Cleavage Fracture ◽  
Fracture Stress ◽  
Cleavage Fracture Stress
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