Threshold for Stress Corrosion Cracking Initiation of Alloy X750 under Long-Term Uniaxial Constant Load Test in High-Temperature Water

CORROSION ◽  
2004 ◽  
Vol 60 (3) ◽  
pp. 229-236 ◽  
Author(s):  
M. Yamamoto ◽  
J. Kuniya ◽  
S. Uchida
Keyword(s):  
High Temperature ◽  
Crack Initiation ◽  
Stress Corrosion ◽  
Applied Stress ◽  
Stress Level ◽  
Stress Corrosion Cracking ◽  
Pure Water ◽  
Constant Load ◽  
Corrosion Cracking ◽  
Load Test

Abstract Uniaxial constant load (UCL) tests of the nickel-based alloy X750 (UNS N07550) were performed in high-temperature pure water (288°C, 8 ppm dissolved oxygen [DO]) to investigate stress corrosion cracking (SCC) fracture time and the crack initiation process. The SCC fracture was initiated at a stress level below the 0.2% offset yield stress and many small cracks were observed in the middle of the nonfractured test specimens. The distribution of the crack length for each observation time is shown by Weibull probability distributions. Crack initiation and propagation process had different behavior depending on the applied stress level and the stress intensity factor at the crack tip. SCC initiation at the minimum applied stress is discussed with respect to the grain size, which depended on the size of an initial crack.

Stress Corrosion Cracking of Inconel Alloys and Weldments in High-Temperature Water — the Effect of Sulfuric Acid Addition

CORROSION ◽  
1988 ◽  
Vol 44 (4) ◽  
pp. 239-247 ◽  
Author(s):  
A. McMinn ◽  
R. A. Page
Keyword(s):  
Sulfuric Acid ◽  
Strain Rate ◽  
Stress Corrosion ◽  
Crack Growth ◽  
Stress Corrosion Cracking ◽  
Pure Water ◽  
Water Environment ◽  
Constant Load ◽  
Corrosion Cracking ◽  
Weld Metals

Abstract The stress corrosion cracking (SCC) susceptibilities of Alloys 600 and 690, AISI 316 NG stainless steel (SS), ASTM A508 carbon steel, and a number of compatible weld metals have been evaluated at 288 C in pure water and in pure water containing sulfuric acid additions. The sulfuric acid was added to simulate the effects of a resin release from the demineralizer system of a boiling water reactor (BWR). A combination of creviced and noncreviced slow strain rate, constant load, and crack growth rate tests were used in the evaluation. The results indicated that all of the alloys tested in the uncreviced condition were immune to cracking in the pure water environment. The presence of crevices in the pure water environment produced a susceptibility to SCC in Alloy 600, in Inconel I-82 and I-182 weld metals, and ASTM A508 steel, but not in Alloy 690. Cracking was enhanced by the addition of 1 ppm H2SO4 in slow strain rate tests (SSRTs) and constant load tests, but crack growth rates were not enhanced. All of the alloys tested in the resin intrusion environment were susceptible to cracking, except for the high chromium weld metals R-135 and Inconel I-72.

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