Crack Initiation and Growth Analysis by Direct Optical Observation during SSRT in High Temperature Water

CORROSION ◽  
1984 ◽  
Vol 40 (3) ◽  
pp. 120-126 ◽  
Author(s):  
Takashi Kawakubo ◽  
Mamoru Hishida
Keyword(s):  
High Temperature ◽  
Crack Initiation ◽  
Crack Growth ◽  
Optical Observation ◽  
Observation System ◽  
Slow Strain Rate Test ◽  
Cracking Behavior ◽  
High Temperature Water ◽  
Rate Test ◽  
Temperature Water

Abstract The stress corrosion cracking behavior during the slow strain rate test (SSRT) has been investigated in high temperature water. SSRTs were performed on center-notched thin plate specimens of sensitized Type 304 stainless steel. A direct optical observation system consisting of single crystal sapphire windows was employed to separate the SCC into an initiation and a growth stage, and to measure the crack growth rate. Effects of the extension rate, test temperature, and dissolved oxygen concentration on the crack initiation and growth were examined. The crack growth data were analyzed with different variables, including the elastic plastic fracture mechanics parameters. The best interpretation of the crack growth rates is obtained by plotting them vs the time differential of J-integral, which is an estimate of the crack tip deformation rate during SSRT.

CF/SCC Interaction on Structural Materials for LWR in High Temperature Water

2002 ◽  
Author(s):  
Yasuyuki Katada ◽  
Shigeo Ohashi
Keyword(s):  
High Temperature ◽  
Water Type ◽  
Loading Test ◽  
High Temperature Water ◽  
Rate Test ◽  
Loading Modes ◽  
Type 3 ◽  
Temperature Water

A test apparatus was developed to study the interaction between corrosion fatigue (CF) and stress corrosion cracking (SCC) in high-temperature water simulated boiling water reactor environment. Tests were conducted using 1/2T-CT samples of both low alloy and sensitized stainless steels under 3 different types of loading at 0.2–8 ppm in dissolved oxygen concentrations at 563 K in water. Type 1 was a normal cyclic loading test of constant amplitude, Type 2 a monotonic constant loading rate test, and Type 3 a combination of Type 1 + Type 2 loading modes. In the low alloy steel, no striking interaction was observed between CF and SCC, whereas in the case of Type 3 loading condition crack growth rates of the sensitized stainless steel were as much as 3 times higher than those for Type 1 + Type 2. The mechanism of the CF and SCC interaction is discussed.

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