Numerical prediction of thermal aging and cyclic loading effects on fracture toughness of cast stainless steel CF8A: Experimental and numerical study

2019 ◽  
Vol 163 ◽  
pp. 105120 ◽  
Author(s):  
Gyo-Geun Youn ◽  
Hyun-Suk Nam ◽  
Yun-Jae Kim ◽  
Jin-Weon Kim
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Cyclic Loading ◽  
Thermal Aging ◽  
Numerical Study ◽  
Numerical Prediction ◽  
Loading Effects ◽  
Cast Stainless Steel

Fracture Toughness of Z3CN20.09M Cast Stainless Steel with Long-Term Thermal Aging

2017 ◽  
Vol 26 (9) ◽  
pp. 4442-4449 ◽  
Author(s):  
Weiwei Yu ◽  
Dunji Yu ◽  
Hongbo Gao ◽  
Fei Xue ◽  
Xu Chen
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Thermal Aging ◽  
Cast Stainless Steel

Effects of thermal aging on the fracture toughness of cast stainless steel CF8

2019 ◽  
Vol 173 ◽  
pp. 45-54 ◽  
Author(s):  
David A. Collins ◽  
Emily L. Barkley ◽  
Timothy G. Lach ◽  
Thak Sang Byun
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Thermal Aging ◽  
Cast Stainless Steel

Fracture Behavior of Aged CF8A Austenite Cast Stainless Steel Under Dynamic and Cyclic Loading Conditions

2017 ◽  
Author(s):  
Jin Weon Kim ◽  
Myung Rak Choi ◽  
Yun Jae Kim
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Cyclic Loading ◽  
Dynamic Loading ◽  
Thermal Aging ◽  
Fracture Behavior ◽  
Operating Temperature ◽  
Loading Conditions ◽  
Loading Effect ◽  
Loading Rates

This study conducted J-R fracture toughness tests using aged CF8A cast austenitic stainless steel (CASS) under dynamic and cyclic loading conditions at room temperature (RT) and 316°C and investigated the effect of seismic loading characteristics on the fracture behavior of age-related degraded material. For comparison, J-R fracture tests were also conducted on unaged CF8A CASS. CF8A CASS was made as a static casting, and it was aged thermally at 400°C for 175 days, which is equivalent to thermal aging at the operating temperature of nuclear power plants (NPPs) for 32 effective full power years (EFPYs). Monotonic J-R tests were conducted at both quasi-static and dynamic loading rates, and cyclic J-R tests were conducted at a quasi-static loading rate. The results showed that the fracture resistance of aged CF8A CASS under monotonic load was lower, by ∼35%, than that of unaged CF8A CASS, regardless of test temperatures and loading rates. The dynamic loading effect on fracture behavior was almost negligible for both unaged and aged CF8A CASSs at RT and 316°C. Cyclic loading reduced J-R fracture toughness of unaged CF8A CASS considerably at both test temperatures. Such a cyclic loading effect on fracture behavior was still observed from aged CF8A CASS. Thus, we conclude that the dynamic and cyclic loading effects on fracture behavior of CF8A CASS were not altered by thermal aging at the operating temperature of NPPs for 32 EFPYs.

An evaluation of cast stainless steel (CF8M) fracture toughness caused by thermal aging at 430°C

2002 ◽  
Vol 16 (7) ◽  
pp. 902-910 ◽  
Author(s):  
Jae Do Kwon ◽  
Jae Hyun Ihn ◽  
Joong Cheul Park ◽  
Sung Jong Choi ◽  
Yun Won Park
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Thermal Aging ◽  
Cast Stainless Steel

Fracture Toughness of Aged Stainless Steel Primary Piping and Reactor Vessel Materials

1987 ◽  
Vol 109 (4) ◽  
pp. 440-448 ◽  
Author(s):  
W. J. Mills
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Ductile Fracture ◽  
Thermal Aging ◽  
Fracture Resistance ◽  
Reactor Vessel ◽  
Initiation Toughness ◽  
Second Phase ◽  
Premature Failure ◽  
Fracture Properties

The ductile fracture toughness behavior of FFTF primary piping and reactor vessel construction materials was characterized using the multiple-specimen JR-curve technique before and after 10,000-hr thermal aging treatments. The test materials included Types 304 and 316 stainless steel (SS) and Types 308 and 16–8–2 SS welds. In the unaged condition, these alloys exhibited very high Jc initiation toughness and tearing modulus values at elevated temperatures (427–538°C). The fracture resistance for the 316 SS piping was found to be dependent on orientation; Jc values for the axial (C–L) direction were 60 to 70 percent lower than those for the circumferential (L–C) orientation. The lower fracture properties in the C–L orientation resulted from premature failure of stringers aligned in the axial direction. Thermal aging at 427° C caused no degradation in fracture resistance, while 482 and 566° C agings resulted in a modest 10 to 20 percent reduction in Jc for both base and weld metals. Residual toughness levels after aging are adequate for precluding any possibility of nonductile fracture. Hence, conventional stress and strain limits, such as those provided by the ASME Code, are sufficient to guard against ductile fracture for SS components that have accumulated 10,000-hr exposures at or below 566° C. Metallographic and fractographic examinations revealed that the degradation in fracture properties was associated with aging-induced second-phase precipitation.

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