Room Temperature Creep and Its Influence on Fatigue Crack Growth in a 304 Stainless Steel

2005 ◽  
Vol 297-300 ◽  
pp. 1083-1088 ◽  
Author(s):  
Jie Zhao ◽  
Tao Mo ◽  
Weixing Chen ◽  
Fu Gang Wang
Keyword(s):  
Stainless Steel ◽  
Fatigue Crack ◽  
Stress Intensity ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Room Temperature ◽  
304 Stainless Steel ◽  
Propagation Mode ◽  
Temperature Creep ◽  
Room Temperature Creep

The current paper investigated the phenomena of room temperature creep at the crack tip and its influence on fatigue crack growth behavior of a 304 stainless steel. From the experiments, a time-dependent deformation is obviously observed under various stress intensity factors. The deformation depends on stress intensity factor as well as load history. Both acceleration and retardation of fatigue crack growth are found after room temperature creep, which rest on load patterns. A distinct marking line was seen on the fracture surface following the holding period. It is proposed that the crack propagation mode changed after the hold time.

Room Temperature Creep and its Effect on Fatigue Crack Growth in a X70 Steel with Various Microstructures

2007 ◽  
Vol 353-358 ◽  
pp. 138-141 ◽  
Author(s):  
De Fu Nie ◽  
Jie Zhao
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Room Temperature ◽  
Pipeline Steel ◽  
Threshold Region ◽  
Single Wave ◽  
Temperature Creep ◽  
Crack Tips ◽  
Room Temperature Creep

Fatigue crack growth (FCG) tests have been performed in an X70 steel with various microstructures (respectively in the as-received and the normalized condition). The effect of room temperature creep (RTC) on FCG behavior has been investigated by comparing with single wave overloads (SWOL). The as-received X70 pipeline steel has high FCG rate at the near-threshold region. While at the Paris region, FCG rate seems insensitive to the microstructure. In both conditions, time-dependent deformation is observed at crack tips (i.e., RTC), which increases with increasing stress-intensity-factor. And this deformation has a high value in the normalized state, under identical testing conditions. Both RTC and SWOL can bring subsequent fatigue crack growth a very short initial acceleration before deceleration, whereas the former induces more serious deceleration and retardation, which attributes to more significant crack closures.

Results of High Stress Ratio and Low Stress Intensity on Fatigue Crack Growth Rates for 304 Stainless Steel in 288°C Water

2002 ◽  
Author(s):  
William M. E. Evans ◽  
G. L. Wire
Keyword(s):  
Growth Rate ◽  
Stainless Steel ◽  
Fatigue Crack ◽  
Stress Intensity ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
High Stress ◽  
304 Stainless Steel ◽  
Crack Growth Rates

Fatigue crack growth rate tests were performed on a 304 stainless steel compact tension (CT) specimen in water with 40–60 cc/kg H2. Data in the literature for CT tests show minor environmental effects in hydrogenated water, but higher effects in oxygenated water. However, the PWR data presented by Bernard, et al (1979) were taken at low stress ratios (R = 0.05) and high stress intensity levels (ΔK = 16–41 MPa√m). The purpose of these tests is to explore the crack growth rate characteristics of 304 SS in hydrogenated water at higher R values (0.7 and 0.83) and lower ΔK values (11.0 and 7.7 MPa√m) Each set of R, ΔK conditions were tested at frequencies of 0.1, 0.01 and 0.001 Hz. The results show a pronounced effect on crack growth rates when compared to available literature data on air rates.

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