Extremely Slow Strain Rate Stress-Corrosion Testing Machine and Some Experimental Results
1979 Volume 65 Issue 2 Pages 212-218
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1979 Volume 65 Issue 2 Pages 212-218
An extremely slow strain rate testing machine for stress-corrosion cracking (SCC), which can be continuously controlled with cross-head speeds over the range of 1.5×10-5cm/s to 7.7×10-9cm/s, has been newly devised and constructed.
Stress corrosion behavior of Type 304 stainless steel in 143°C 42%MgCl2 at the potential of-0.34 V (SCE), and of Inconel 600 and Incoloy 800 in 140°C 50%NaOH at the potential of 0 V (SCE) was examined by the newly devised testing machine.
SCC was observed to occur most severely at a strain rate of 3.3×10-6 s-1 for 304 stainless steel and 1.7×10-6 s-1 for Inconel 600 and Incoloy 800, and the susceptibility decreased at strain rates faster or slower than those for all specimens tested. For 304 stainless steel transgranular cracking was formed at the region of slower strain rates and intergranular at faster strain rates but the reverse was the case for Inconel 600 and Incoloy 800.
