Environmental Fatigue Crack Propagation Behavior of Cast Stainless Steels under PWR Condition

2005 ◽  
Vol 297-300 ◽  
pp. 968-973 ◽  
Author(s):  
Ill Seok Jeong ◽  
Sang Jai Kim ◽  
Taek Ho Song ◽  
Jong Jooh Kwon ◽  
Sung Yul Hong ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Nuclear Power ◽  
Power Plants ◽  
Pressurized Water Reactor ◽  
Pressurized Water ◽  
Fatigue Crack Propagation Behavior ◽  
Propagation Behavior ◽  
Crack Propagation Behavior

Environmental fatigue crack propagation of CF8M and CF8A steels used in the domestic nuclear power plants (NPPs) were investigated on the simulated pressurized water reactor (PWR) condition (temperature: 316°C, pressure: 15MPa). The test equipment for environmental fatigue (high temperature-high pressure loop, autoclave, load frame, and measurement system) was designed. As-received and 60-year aged specimens were used in the test. To compare with environmental fatigue test, another test in the air condition was performed. The fracture surfaces of specimens were difficult to verify the fracture modes such as striation, inter-granular crack and cleavage and so on. As the ferrite content of CF8M is increased, more particles on the fracture surface were peeled.

Effect of Biaxial Static Loads on Fatigue Crack Propagation Behavior under Cyclic Tensile and Torsional Loading

2006 ◽  
Vol 321-323 ◽  
pp. 720-723
Author(s):  
Yong Hak Huh ◽  
Philip Park ◽  
Dong Jin Kim ◽  
Jun Hyub Park
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Growth Rates ◽  
Biaxial Loading ◽  
Torsional Loading ◽  
Static Loads ◽  
Fatigue Crack Propagation Behavior ◽  
Propagation Behavior ◽  
Crack Propagation Behavior

Fatigue crack propagation behavior under cyclic tensile or torsional loading with biaxial static loads has been investigated. Two different biaxial loading systems, i.e. cyclic tensile loading with static torsional load and cyclic torsional loading with static tensile load, were employed to thin-walled tubular specimens. The crack propagation was measured by two crack gages mounted near the notch and crack opening level was measured by unloading compliance method. The directions of the fatigue crack propagated under respective biaxial loading conditions were examined and the growth rates were evaluated by using several cyclic parameters, including equivalent stress intensity factor range, Keff, crack tip opening displacement range, CTD, minimum strain energy density factor range, Smin. Furthermore, the growth rates were evaluated by effective cyclic parameters considering crack closure. It was found that the biaxial static stress superimposed on the cyclic tensile or torsional loading tests has no influence on the propagation directions of the cracks. Furthermore, it was shown that the fatigue crack growth rates under biaixial faigue loading were well expressed by using the cyclic fatigue parameters, Keq,eff, CTDeff, Smin,eff considering crack closure effect.

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