A test program has been carried out in order to evaluate the effect of increased pressure on the sensitivity towards HISC for welded 22% Cr and 25% Cr pipe material. The testing has been performed at two crack tip opening displacement (CTOD) levels in four point bend at 1 bar and 100 bars pressure at -1 °C in 3.5% NaCl in distilled water. The applied cathodic potential was -1050 mVsce. In addition hydrogen charging experiments have been conducted on the 25Cr material at 1 bar and 100 bars.

The results show that both the 22% Cr and the 25% Cr material have poor crack growth resistance for surface breaking, fatigue sharpened cracks. The crack growth started at a CTOD level of 0.01 mm. It appears as there is an increased sensitivity at 100 bars compared to 1 bar. The hydrogen level measured after 324 days of charging was only marginally higher at 100 bars than at 1 bar.

Subject
Test methods, Crack growth, Materials, Hydrogen concentration, Hydrostatic pressure, Stress cracking, Hydrogen charging, Cracking, Fatigue, Cracks, Weld metal, Hydrogen, Samples
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2006
Association for Materials Protection and Performance (AMPP)
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